JP3183356B2 - Method and apparatus for driving brushless DC motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless DC motor control method and apparatus, and more particularly, to a brushless DC motor control method and apparatus.
Brushless D having a rotor having a permanent magnet provided on a rotor core and an armature having a three-phase winding provided on an armature core
A method and apparatus for controlling a C motor.

[0002]

2. Description of the Related Art Conventionally, as a motor for driving a compressor,
Focusing on the advantages of being able to be driven by AC voltage at the commercial frequency, being able to easily achieve robustness as a whole, and being able to change the number of revolutions by simultaneously changing the frequency and voltage of the power supply applied to the motor using an inverter. In general, an induction motor is used. However, it is known that the ratio of the mechanical output to the secondary input is (1-s) due to its configuration. Cannot do it. Here, s is a slip, and indicates a ratio of a secondary copper loss, which is a loss caused by a current flowing on the secondary side (rotor).

In recent years, there has been a strong demand for driving a compressor using a motor having a higher efficiency than an induction motor. In addition, ferrite magnets having a large coercive force and being inexpensive have been required. In order to satisfy the above demand, since a rare earth magnet has been provided, an armature provided with a permanent magnet on a rotor core and an armature provided with a three-phase winding on an armature core have been developed. Attempts have been made to employ a brushless DC motor having the following and control the frequency and voltage of a power supply applied to the brushless DC motor by an inverter to achieve variable speed operation. That is, unlike an induction motor, a brushless DC motor has no rotor and no current flows on the rotor side, so the secondary copper loss becomes zero and the secondary copper loss becomes zero. Higher efficiency can be achieved by the same amount.

[0004]

The above brushless DC
When the motor control method is adopted, the compressor cannot be operated because the output sharply drops in a high-speed rotation region where the induced voltage approaches the maximum output voltage of the inverter due to the characteristics of the brushless DC motor. In particular, when driving the compressor of an air conditioner, since not only high efficiency but also rapid warming performance and maximum capacity are strongly demanded, the compressor is driven in the high speed rotation range of the brushless DC motor. Must.

Therefore, in consideration of these points, the induced voltage of the brushless DC motor must be set low. If the induced voltage is set low, the current of the brushless DC motor increases, and the rated point is reduced. However, there is an inconvenience that the efficiency of the method is reduced. More specifically, the characteristics of a brushless DC motor having a rotor in which a permanent magnet is attached to the periphery of the rotor core are as shown in FIG. 22, the vertical axis represents the induced voltage and output of the motor, and the horizontal axis represents the motor. The axis is the rotation speed of the motor. The heating rating and the cooling rating are shown in consideration of the case where the compressor of the air conditioner is driven.

As is apparent from FIG. 22, the induced voltage of the motor increases in proportion to the rotation speed, but the output of the motor is
Until the induced voltage of the motor approaches the rotation speed at which it becomes equal to the maximum voltage of the inverter (hereinafter, referred to as the maximum rotation speed), the voltage increases substantially in proportion to the rotation speed, and thereafter decreases rapidly. Therefore, the heating rating must be set to a lower rotation speed than the rotation speed at which the motor output starts to decrease. However, since the brushless DC motor can only operate up to the maximum rotation speed, it is not possible to perform temporary high-speed operation by inverter control, and the operating range is narrowed. In order to eliminate such inconvenience, FIG.
When the maximum rotation speed is set high as shown in FIG. 3, the induced voltage of the motor at the same rotation speed becomes lower than that of the characteristic shown in FIG. FIG.
Is a diagram showing the efficiency of the motor corresponding to the fluctuation of the rotation speed. It can be seen that the efficiency decreases when the maximum rotation speed is set high and the operation range is expanded.

Although the above description has been given of the case where the compressor is driven by using the brushless DC motor, the same disadvantage occurs when the brushless DC motor is used for other purposes.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and provides a brushless DC motor control method and apparatus capable of achieving high efficiency of a brushless DC motor and achieving high speed rotation. It is an object.

[0009]

According to a first aspect of the present invention, there is provided a brushless DC motor control method, wherein an output current of an inverter is increased so that a phase of an armature current of the brushless DC motor is advanced over an induced voltage. Alternatively, it is a method of controlling the voltage. A brushless DC motor control method according to a second aspect is a method using a brushless DC motor having a rotor having a permanent magnet embedded in a rotor core.

A brushless DC motor control method according to a third aspect is a method of driving a compressor by a brushless DC motor. The brushless DC motor control device according to claim 4 is
An inverter control means for controlling the output current or voltage of the inverter so as to advance the phase of the armature current of the brushless DC motor beyond the induced voltage is included.

According to a fifth aspect of the present invention, there is provided a brushless DC motor control device, wherein the inverter control means includes a rotor position / speed detection means for detecting a rotation position and a rotation speed of a rotor of the brushless DC motor; A leading phase angle holding means for outputting a corresponding leading phase angle, a switching command for outputting a switching command to be supplied to the inverter with a voltage command determined based on a rotation speed command for the brushless DC motor and the outputted leading phase angle being input. And output means.

According to a sixth aspect of the present invention, there is provided a brushless DC motor driving device, wherein the inverter control means includes a rotor position / speed detection means for detecting a rotation position and a rotation speed of a rotor of the brushless DC motor; Advanced phase angle holding means for outputting a corresponding advanced phase angle, advanced phase angle correction means for correcting the output advanced phase angle based on a deviation of the actual rotational speed from the rotational speed command, and a corrected advanced phase An advanced phase angle limiting means for limiting the angle so as not to exceed a predetermined advanced phase angle; a voltage command determined based on a rotational speed command for the brushless DC motor and a corrected advanced phase angle limited as necessary. Using switching command output means for outputting a switching command to be supplied to the inverter as an input. That.

According to a seventh aspect of the present invention, the brushless DC motor driving device further includes a current drooping necessity judging means for judging the necessity of the current droop based on the current supplied to the converter. The output phase correction unit corrects the output advance phase angle based on the deviation of the actual rotation speed from the speed command and the result of the necessity determination of the current droop.

The brushless DC motor driving device according to the present invention further includes a rotation speed command correction means for determining whether or not current droop is necessary based on the current supplied to the converter and correcting the rotation speed command. As the angle correction means, a means for correcting the output advance phase angle based on the deviation of the actual rotation speed from the rotation speed command and the current supplied to the converter is used.

According to a ninth aspect of the present invention, there is provided a brushless DC motor driving device, wherein, as inverter control means, a leading phase angle holding means for outputting a leading phase angle corresponding to a rotation speed command, and a voltage command determined based on the rotation speed command and output. And a switching command output means for outputting a switching command to be supplied to the inverter with the advanced phase angle as an input.

According to a tenth aspect of the invention, the brushless DC motor driving device is determined based on an advance phase angle holding unit for outputting an advance phase angle corresponding to the rotation speed command as the inverter control unit, and an output frequency of the inverter in response to the rotation speed command. Leading phase angle correction means for correcting the output leading phase angle based on the deviation of the rotational speed, leading phase angle limiting means for limiting the corrected leading phase angle so as not to exceed a predetermined leading phase angle, A switching command output means for outputting a switching command to be supplied to the inverter with a rotation speed command and a corrected and limited advance phase angle as required as input is used.

The brushless DC motor driving device according to the eleventh aspect of the present invention further includes a current droop necessity judging means for judging the necessity of the current droop based on the current supplied to the converter. A device for correcting the output advance phase angle based on the deviation of the rotation speed determined based on the output frequency of the inverter with respect to the speed command and the result of the necessity determination of the current droop is used.

A brushless DC motor driving apparatus according to a twelfth aspect of the present invention further includes a rotation speed command correction means for determining whether or not current droop is necessary based on the current supplied to the converter and correcting the rotation speed command. As the angle correcting means, a means for correcting the output advance phase angle based on a rotational speed deviation determined based on an output frequency of the inverter with respect to the rotational speed command and a current supplied to the converter is used.

According to a thirteenth aspect of the present invention, the brushless DC motor driving device uses a brushless DC motor having a rotor in which a permanent magnet is embedded in a rotor core. The brushless DC motor driving device according to claim 14 uses a brushless DC motor that drives a compressor.

[0020]

According to the brushless DC motor control method of the present invention, there is provided a brushless DC motor having a rotor having a permanent magnet provided on a rotor core and an armature having a three-phase winding provided on an armature core. When controlling the three-phase alternating current supplied to the three-phase winding by the inverter, the output current or the voltage of the inverter is controlled so that the phase of the armature current of the brushless DC motor advances beyond the induced voltage. The induced voltage can be reduced, and as a result, high-speed rotation can be achieved.

According to the brushless DC motor control method of the present invention, since the brushless DC motor has the rotor in which the permanent magnet is embedded in the rotor core, the induced voltage can be greatly reduced. As a result, higher speed rotation can be achieved. According to the brushless DC motor control method of the third aspect, since the brushless DC motor drives the compressor, the rated rotation speed can be made 60% or more of the maximum rotation speed by the conventional control, and the high speed of the compressor drive can be achieved. Efficiency can be achieved.

According to a fourth aspect of the present invention, there is provided a brushless DC motor control device including a rotor having a permanent magnet provided on a rotor core and an armature having a three-phase winding provided on an armature core. When the three-phase alternating current supplied to the three-phase winding is controlled by an inverter, a brushless D
Since the output current or voltage of the inverter is controlled by the inverter control means so that the phase of the armature current of the C motor advances beyond the induced voltage, the induced voltage can be reduced, and as a result, high-speed rotation can be achieved.

According to the brushless DC motor control device of the present invention, the brushless DC motor control device can be used as an inverter control means.
Rotor position / speed detection means for detecting the rotation position and rotation speed of the rotor of the motor; advance phase angle holding means for outputting an advance phase angle corresponding to the rotation speed of the brushless DC motor; and rotation speed for the brushless DC motor And a switching command output unit that outputs a switching command to be supplied to the inverter with a voltage command determined based on the command and an output advanced phase angle as an input, so that the rotation speed of the brushless DC motor is controlled. A correspondingly predetermined advance phase angle is output from the advance phase angle holding means, and a switching command is output from the switching command output means in consideration of the output advance phase angle and supplied to the inverter, Brushless DC
The induced voltage can be reduced by advancing the phase of the armature current of the motor beyond the induced voltage, and as a result, high-speed rotation can be achieved.

According to the brushless DC motor driving device of the present invention, the brushless DC motor can be used as the inverter control means.
Rotor position / speed detection means for detecting the rotation position and rotation speed of the rotor of the motor; advance phase angle holding means for outputting an advance phase angle corresponding to the rotation speed of the brushless DC motor; Leading phase angle correction means for correcting the output leading phase angle based on the deviation of the rotational speed, leading phase angle limiting means for limiting the corrected leading phase angle so as not to exceed a predetermined leading phase angle, A switching command output means for outputting a switching command to be supplied to the inverter with a voltage command determined on the basis of a rotation speed command for the brushless DC motor and a corrected and restricted advance phase angle as required as an input. Therefore, the advance phase angle determined in advance corresponding to the rotation speed of the brushless DC motor In addition to the output from the angle holding means, the advance phase angle is corrected by the advance phase angle correction means in consideration of whether the deviation of the rotational speed is positive or not. In order not to exceed the angle, the leading phase angle is limited by the leading phase angle limiting means as necessary, and the switching command is output from the switching command output means in consideration of the corrected and limited leading phase angle as necessary. Is output and supplied to the inverter, the phase of the armature current of the brushless DC motor can be advanced more than the induced voltage, and the induced voltage can be reduced. As a result, high-speed rotation can be achieved. As apparent from the above description, even if the advanced phase angle held by the advanced phase angle holding means is not accurate, the advanced phase angle correction means corrects the phase to be an accurate advanced phase angle. In addition, the phase of the armature current of the brushless DC motor can be reliably advanced beyond the induced voltage to reduce the induced voltage, and as a result, high speed rotation can be achieved.

According to the brushless DC motor driving device of the present invention, the device further includes a current drooping necessity judging means for judging the necessity of current drooping based on the current supplied to the converter, and as a lead phase angle correcting means. Based on the deviation of the actual rotation speed with respect to the rotation speed command and the result of the current droop necessity determination result, the output advance phase angle is corrected, so that the current droop is unnecessary by the current droop necessity determination means. When it is determined that there is, the same operation as in claim 6 can be achieved. Conversely, when it is determined that the current droop is necessary, the lead phase angle correction means corrects the lead phase angle to be small. The current droop at high speed,
And can be achieved with high accuracy.

In the brushless DC motor driving apparatus according to the present invention, the apparatus further includes a rotation speed command correction means for determining whether or not current droop is necessary based on the current supplied to the converter and correcting the rotation speed command. As the advance phase angle correction means, which corrects the output advance phase angle based on the deviation of the actual rotation speed with respect to the rotation speed command and the energizing current of the converter, it is necessary that the current droop is necessary. The rotational speed command can be corrected by the rotational speed command correcting means to lower the rotational speed command based on the discrimination result shown, and the advance phase angle is corrected based on the converter energizing current in addition to the function of claim 6, so that the converter Inverter control is performed to minimize the energizing current, and a more efficient drive of the brushless DC motor can be achieved.

According to the brushless DC motor control device of the ninth aspect, as the inverter control means, an advanced phase angle holding means for outputting an advanced phase angle corresponding to the rotational speed command;
A switching command output unit that outputs a switching command to be supplied to the inverter with a voltage command determined based on the rotation speed command and an output advance phase angle as input is used. A predetermined advance phase angle is output from the advance phase angle holding means, and a switching command is output from the switching command output means in consideration of the output advance phase angle and supplied to the inverter, so that the brushless The induced voltage can be reduced by advancing the phase of the armature current of the DC motor beyond the induced voltage, and as a result, high-speed rotation can be achieved. A mechanism for detecting the rotational position and rotational speed of the rotor,
Since an electric circuit or the like can be eliminated, the configuration can be simplified.

According to a tenth aspect of the present invention, as the brushless DC motor drive device, the inverter control means outputs a leading phase angle corresponding to the rotational speed command, and a leading phase angle holding means for outputting the leading phase angle corresponding to the rotational speed command. Leading phase angle correction means for correcting the output leading phase angle based on the deviation of the rotation speed determined in advance, and leading phase angle limiting means for limiting the corrected leading phase angle so as not to exceed a predetermined leading phase angle. And a switching command output unit that outputs a switching command to be supplied to the inverter with the rotation speed command and the corrected and advanced phase angle limited as necessary as input. In addition to outputting a predetermined advance phase angle corresponding to the speed command from the advance phase angle holding means, the deviation of the rotational speed is The advance phase angle is corrected by the advance phase angle correction means in consideration of whether or not the state is in the above state, and the advance phase angle is limited as necessary so that the corrected advance phase angle does not exceed the predetermined advance phase angle. Means for outputting a switching command from the switching command output means and supplying it to the inverter in consideration of the corrected and, if necessary, the advanced phase angle. The induced voltage can be reduced by advancing the phase of the armature current beyond the induced voltage, and as a result, high-speed rotation can be achieved. As apparent from the above description, even if the advanced phase angle held by the advanced phase angle holding means is not accurate, the advanced phase angle correction means corrects the phase to be an accurate advanced phase angle. , Brushless D
The phase of the armature current of the C motor can be reliably advanced beyond the induced voltage to reduce the induced voltage, and as a result, high speed rotation can be achieved. Further, a mechanism for detecting the rotational position and the rotational speed of the rotor, an electric circuit, and the like can be eliminated, so that the configuration can be simplified.

According to the eleventh aspect of the present invention, the brushless DC motor driving device further includes a current drooping necessity judging means for judging the necessity of current drooping based on a current supplied to the converter, and as a lead phase angle correcting means. Based on the deviation of the rotation speed determined based on the output frequency of the inverter with respect to the rotation speed command and the result of the current drooping necessity determination,
Since the output lead phase angle is used to correct the output phase angle, when the current drooping necessity determining means determines that the current drooping is unnecessary, the same operation as in claim 10 can be achieved. If it is determined that the current droop is necessary, the lead phase angle correction means performs correction so as to reduce the advance phase angle, so that the current droop can be achieved at high speed and with high accuracy.

According to the twelfth aspect of the present invention, the brushless DC motor drive device further includes a rotation speed command correction means for determining whether current droop is necessary based on the current supplied to the converter and correcting the rotation speed command. As the lead phase angle correction means, a means for correcting the output lead phase angle based on the rotation speed deviation determined based on the output frequency of the inverter with respect to the rotation speed command and the energizing current of the converter is used. Can be corrected by the rotation speed command correction means to reduce the rotation speed command based on the determination result indicating that the phase angle is necessary. Compensation is also performed, so inverter control is performed to minimize converter conduction current, resulting in a more efficient brushless The drive of the C motor can be achieved.

According to the brushless DC motor driving device of the thirteenth aspect, since the brushless DC motor has the rotor in which the permanent magnet is embedded in the rotor core, the induced voltage can be greatly reduced. , Can achieve higher speed rotation. According to the brushless DC motor driving device of the present invention, since the brushless DC motor drives the compressor, the rated rotation speed can be made 60% or more of the maximum rotation speed by the conventional control. Efficiency can be achieved.

[0032]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a block diagram schematically showing an embodiment of a brushless DC motor control device according to the present invention. A DC voltage is obtained by supplying an AC power supply 1 to a converter 2 and a DC voltage is further supplied to an inverter 3. The phase AC voltage is obtained and supplied to the armature winding of the brushless DC motor 4. Then, the induced voltage of the brushless DC motor is detected by the induced voltage detecting unit 5 to indirectly detect the magnetic pole position, and the inverter control unit 6 receives the operating frequency command value and the detection signal from the induced voltage detecting unit 5 as inputs, and controls the inverter. 3 is supplied with an inverter control signal for performing current control, voltage control, speed control, and the like.

FIG. 2 is a schematic vertical sectional view showing an example of the configuration of the brushless DC motor 4. An armature 41 formed by winding a three-phase armature winding around an armature core, and a rotor core 42a
And a rotor 42 provided with at least one pair of permanent magnets 42b on the outer periphery of the armature, and by supplying power of frequency f to the armature winding, 120f / P (where P is the number of magnetic poles) The rotor 42 can be rotated at a speed determined by the following. The permanent magnet 42b may be a ferrite magnet, but is preferably a rare earth magnet.

The inverter control unit 6 includes a brushless D
The output current or voltage of the inverter 3 is controlled so that the phase of the armature current of the C motor 4 is advanced from the induced voltage. The operation of the brushless DC motor control device having the above configuration is as follows. When a predetermined control signal is supplied to the inverter 3 by the inverter control unit 6, the inverter 3 performs a switching operation in response to the control signal to supply predetermined AC power to the armature winding of the brushless DC motor 4, The rotor 42 of the DC motor 4 can be driven to rotate. In this case, the phase of the armature current ia supplied to the armature winding of the brushless DC motor 4 by the inverter 3 controlled by the inverter control unit 6 is advanced from the phase of the induced voltage of the brushless DC motor 4. Since the brushless DC motor 4 is driven by the inverter 3, the induced voltage is reduced, and the number of revolutions at which the induced voltage is equal to the maximum voltage of the inverter is increased. Can be achieved.

This will be described in more detail. It is known that the voltage equation of a brushless DC motor is represented by Equation 1.

[0036]

(Equation 1)

Where R is the armature winding resistance, id is the current of the armature current in the direct axis direction, iq is the current of the armature current in the horizontal axis direction, vd and vq are the corresponding voltages, Ld and Lq, respectively.
Is the corresponding inductance, ω is the rotational angular velocity,
ψa is the effective value of the armature linkage flux by the permanent magnet,
Indicates the coefficient of the induced voltage. Further, the generated torque τ is represented by Expression 2.

[0038]

(Equation 2)

Here, P is the number of pole pairs. The maximum output current of the inverter is Iomax, and the maximum output voltage is Vom.
If ax is used, the armature winding current ia and the terminal voltage va of the brushless DC motor 4 are limited as shown in Expressions 3 and 4, respectively.

[0040]

(Equation 3)

[0041]

(Equation 4)

However, brushless D for high efficiency
Since R is set to be as small as possible for the C motor, Equation 4 can be approximated as shown in Equation 5.

[0043]

(Equation 5)

Conventionally, an id = 0 control method has been generally adopted as a control method for a brushless DC motor. In this case, Equations 2, 3, and 4 are as follows. τ = Pψaiq | ia | = | iq | ≦ Iomax | va | = ω {(ψa) 2 + (Lqiq) 2} 1/2 ≦ Vomax Then, in a general brushless DC motor .phi.a
>> Lqiq, the rotational speed increases, and when the induced voltage ωψa approaches the maximum output voltage Vomax of the inverter 3, the generated torque τ rapidly decreases as shown in FIG.
Driving becomes impossible (here, ωψa = Vomax
Is assumed to be ω0). Therefore, when a brushless DC motor is used for driving the compressor of the air conditioner, the rated cooling / heating speed is set to ω0 as shown in FIG.
Value (generally less than about 60% of ω0), and even though the brushless DC motor itself can operate with high efficiency, it is practically near the cooling / heating rated point. Then, it was not possible to perform a highly efficient operation.

However, in this embodiment, since the phase of the armature current ia is advanced from the phase of the induced voltage,
id becomes negative, and as can be seen from Equation 5, (ψa + Ldi
d) <ψa, and the rotation speed at which | va | = Vomax can be made larger than ω0. Therefore, the operation range of the brushless DC motor 4 can be extended to the high-speed rotation region, and the rated rotation speed for cooling / heating can be set to be larger than about 60% of ω0, and high-speed rotation at startup can be achieved.

FIG. 3 is a schematic longitudinal sectional view showing another example of the configuration of a brushless DC motor to which the control method of the present invention is applied. The difference from the brushless DC motor of FIG. 2 is that a permanent magnet 42b is connected to a rotor core 42a. It is only the point embedded inside. In the brushless DC motor having the configuration shown in FIG. 3, the air gap can be reduced because the permanent magnet 42b is embedded in the rotor core 42a, and the inductance L
d becomes larger than that of the brushless DC motor having the configuration of FIG. Therefore, the induced voltage can be further reduced, and the high-speed operation region can be further expanded.

FIG. 4 shows a case where id = 0 control is applied to a brushless DC motor having a permanent magnet disposed on the surface of a rotor {see FIG. 4A}, and a case where id <0 control is applied {(B FIG. 7B is a diagram showing a change in torque with respect to the number of rotations when id <0 control is applied to a brushless DC motor having a permanent magnet embedded inside a rotor {see FIG. It can be seen that high-speed rotation is enabled by applying <0 control, and that even higher speed is enabled by embedding permanent magnets. Incidentally, as is apparent from (C), since the inductance is increased due to the embedded permanent magnet, the torque in the low-speed rotation region is significantly increased.

However, in the brushless DC motor having the rotor 42 in which the permanent magnet 42b is embedded in the rotor core 42a as shown in FIG. 3, the slot ripple is large as shown in FIG. It is known that a considerable amount of noise is generated. In order to reduce the slot ripple, the rotor core 42a having the laminated structure and the embedded permanent magnets 42b are divided into a plurality in the laminating direction, and the rotor 42 is skewed by being shifted by a predetermined angle for each division unit. It is effective to adopt a configuration in which the air gap 4 is generally used to prevent a short circuit of the magnetic flux.
2c is set to be considerably small (permanent magnet 42
The skew angle must be set to a relatively small value because the existence range of the rotor core 42a corresponding to b is as large as possible to achieve the good characteristics of the brushless DC motor.) As a result, the number of divisions of the rotor 42 is significantly increased, and the configuration of the rotor 42 itself is complicated, which makes the manufacturing difficult and increases the cost.

FIG. 6 is a longitudinal sectional view schematically showing a rotor 42 which can solve such inconvenience, can increase the skew angle, and can simplify the structure. The rotor core 42a is embedded in the rotor iron core 42a so as to face a right angle, and a gap 42c is formed in the radial direction to prevent a short circuit of the magnetic force lines so as to communicate with the end face of the permanent magnet. Then, one end of the gap 42c is made to coincide with the outer edge of the end face of the permanent magnet 42b, and the other end of the gap 42c is made to correspond to a predetermined position inward from the inner edge of the end face of the permanent magnet 42b. I have.

Therefore, the skew angle of each divided portion of the rotor core 42a can be increased, and the number of divisions can be reduced, so that the configuration of the rotor 42 can be simplified and the manufacturing can be facilitated. In addition, as shown in FIG. 7, if the gap 42c is formed so that the end facing the outer edge of the end face of the adjacent permanent magnet 42b coincides, the width of the gap 42c can be further increased, so that the skew angle can be further increased. The size can be increased, and the number of divisions can be further reduced.

FIG. 8 is a perspective view showing a specific example in which the rotor core 42a is divided into five parts, and FIG. 9 is a view showing each divided part. An end plate 42d made of a non-magnetic material is provided at both ends of the rotor core 42a. Arrange and fix all the divided parts with fixing members 42 such as pins and bolts.
e. In this specific example, the number of pole pairs is 2 and the skew angle is 3.75 °,
The skew angle between the first divided portion and the fifth divided portion is 15 °, and when the number of slots is 24, it is equivalent to electrically rotating 360 ° with respect to one slot. FIG.
0 is a diagram showing a change in air gap magnetic flux density corresponding to 1 corresponding to the rotational position of the rotor 42, and it can be seen that the slot ripple was significantly reduced as compared with FIG. Further, by selecting a position where the change in the magnetic flux of the rotor core 42a is small as the disposition position of the fixing member 42e, the change in the flow of the magnetic flux can be reduced, and the iron loss is reduced to further increase the efficiency of the brushless DC motor. Can be achieved. In this case, the fixing member 42e may be a non-magnetic material or a magnetic material. Further, a reinforcing plate made of a non-magnetic material may be interposed between the divided portions.

Further, the rotor 42 generally needs to form a hole for passing the refrigerant. However, by making the gap 42c formed as described above function as a hole for passing the refrigerant, the rotor 42 is formed. Special processing is unnecessary. Furthermore, when a hole for refrigerant passage is separately formed, the gap 42c is filled with a filling adhesive obtained by mixing a filler made of a non-magnetic material into the epoxy adhesive, and the permanent magnet is fixed with the epoxy adhesive. By doing so, the fixing member 42e can be omitted. It is of course possible to use both the adhesive fixation with the filling adhesive and the fixation with the bind wire and the non-magnetic metal tube. In this case, it is possible to reduce the diameter of the bind wire and to make the metal tube thinner.

FIG. 11A is a perspective view showing the structure of the permanent magnet, and FIG. 11B is a longitudinal sectional view of the rotor 42.
The only difference from the configuration example is that the end of the permanent magnet 42b facing the other permanent magnet 42b is formed in a convex curved surface. Therefore, in this configuration example, the permanent magnet 4
Since stress concentration on the end of 2b can be reduced and permanent magnets can be prevented from being damaged during high-speed rotation, there is no need to provide special reinforcement, and the configuration of the rotor 42 can be simplified.

FIG. 12A is a perspective view showing another configuration example of the permanent magnet, and FIG. 12B is a longitudinal sectional view of the rotor 42. The difference from the configuration example of FIG. The only point is that it is curved and the central portion is embedded in the rotor core 42a in a state of being pushed into the central axis side of the rotor. Accordingly, in this configuration example, the stress concentration can be reduced not only at the end of the permanent magnet 42b but also over almost the entire range, and the permanent magnet can be more reliably prevented from being damaged during high-speed rotation.

[0055]

Embodiment 2 FIG. 13 is a block diagram showing another embodiment of the brushless DC motor driving apparatus according to the present invention, wherein a DC voltage is obtained by supplying an AC power supply 1 to a converter 2 and further supplied to an inverter 3. To obtain a three-phase AC voltage, and a brushless DC for driving the compressor 4a.
It is supplied to the armature winding of the motor 4. The rotational position detector 51 detects the estimated rotational position of the rotor based on the armature current of the brushless DC motor 4, and the rotational speed calculator 52 detects the rotational speed of the brushless DC motor 4 based on the estimated rotational position detection signal. Is calculated. The input current detection unit 61 detects the current flowing through the converter 2, and the current droop necessity determination unit 62 compares the detected input current with a predetermined reference current to determine whether the current droop is necessary. The rotation speed command is reduced by the rotation speed command reduction unit 63 based on the determination result indicating that the current droop is necessary. Then, by the rotation speed deviation calculation unit 64,
A difference between the reduced rotation speed command and the actual rotation speed calculated by the rotation speed calculation unit 52 is calculated, and a voltage command corresponding to the calculated difference is obtained in the PI control unit 65 and the PWM control unit 66 obtains the voltage command. Supply. Further, based on the rotation speed calculated by the rotation speed calculation unit 52, an advanced phase angle table 6 in which a plurality of advanced phase angles are stored in advance.
7 is read from the PWM control unit 6
6 and the estimated rotation position of the rotor detected by the rotation position detection unit 51 is supplied to the PWM control unit 66 as a reference signal for PWM control. The PWM control unit 66 gives a switching command to the inverter (3) to make the phase of the armature current of the brushless DC motor (4) advance beyond the induced voltage.

The advance phase angle stored in advance in the advance phase angle table 67 is set so that, for example, as shown in FIG. 14, the advance phase angle gradually increases in a region where the rotational speed is low. It is preferable that the phase angle is set so as to rapidly increase in a region where the rotation speed is high to some extent, and is set so that the phase angle is substantially saturated in a region where the rotation speed is extremely high. If the advancing phase angle is set in this way, in a low rotation speed region where the induced voltage of the brushless DC motor 4 does not cause much problem, the advancing phase angle is made sufficiently small to perform almost normal inverter control, and the rotation speed is reduced. In the high rotation speed region where the motor speed has increased to some extent, the leading phase angle is made sufficiently large to sufficiently exhibit the effect of reducing the induced voltage of the brushless DC motor 4, and the operating range can be expanded to the high rotation speed region. In the higher rotation speed region, the advance phase angle is substantially saturated in order to eliminate the inconvenience associated with the excessive advance phase angle. Specifically, for example, it corresponds to the rotation speed on the basis of the generated torque required for the brushless DC motor 4, the armature current in the direct axis direction id, and the relationship of the horizontal axis direction current iq in Equation 6. The advance phase angle can be calculated. However, Va
m is the upper limit of the terminal voltage of the brushless DC motor 4, and p is the salient pole coefficient.

[0057]

(Equation 6)

In this embodiment, not only the voltage command output from the PI controller 65 but also the advance phase angle read from the advance phase angle table 67 corresponding to the rotation speed of the brushless DC motor 4 is used as an input for PWM. Control unit 6
6 outputs the switching command, the phase of the output voltage of the inverter 3 can be advanced by the read advance phase angle, and the armature current supplied to the armature winding of the brushless DC motor 4 can be increased. The phase can be advanced from the phase of the induced voltage of the brushless DC motor 4 by a predetermined phase angle. As a result, the current in the direct axis direction of the armature current becomes negative, and as a result, the induced voltage of the brushless DC motor 4 is reduced, so that the operation range of the brushless DC motor 4 can be expanded. Also, the phase of the output voltage of the inverter 3 and the brushless DC motor 4
Since the phase of the armature current is known in advance in accordance with the rotation speed of the brushless DC motor 4, the advance phase angle corresponding to the rotation speed is determined in advance by the advance phase angle table 67.
In the inverter 3 based on the advance phase angle.
By simply performing PWM control on the armature current, the phase of the armature current can be advanced by a predetermined phase angle with respect to the phase of the induced voltage of the brushless DC motor 4. Therefore, brushless DC
There is no need to detect the phase of the armature current of the motor 4, and the configuration of the brushless DC motor driving device can be simplified.

Further, if the current supplied to converter 2 becomes equal to or greater than a predetermined limit current, a determination result indicating that current droop is necessary is output from current droop necessity judging section 62 and rotation speed command reducing section 63 outputs Reduce the rotation speed command.
Therefore, it is possible to prevent an abnormal increase in the energizing current of converter 2 and to maximize the inverter capacity.

[0060]

Embodiment 3 FIG. 15 is a block diagram showing still another embodiment of the brushless DC motor driving apparatus according to the present invention.
The difference from the embodiment of FIG.
Phase deviation correction calculation unit 68 which calculates a correction amount for the advance phase angle by using the deviation of the rotational speed calculated by the above as an input.
An advanced phase angle correction unit 69 that corrects the advanced phase angle read from the advanced phase angle table 67 based on the calculated correction amount, and the corrected advanced phase angle exceeds a predetermined limit advanced phase angle. The only difference is that it further includes a leading phase angle limiting unit 70 that supplies the PWM signal to the PWM control unit 66 while limiting it so that it does not exist.

Therefore, in the case of this embodiment, when the rotational speed command is higher than the actual rotational speed, a correction is made to increase the advanced phase angle read from the advanced phase angle table 67, and conversely, When the rotation speed command is equal to or less than the actual rotation speed, the correction amount output from the advance phase angle correction calculation unit 68 is reduced, and the advanced phase angle after correction is changed to the advanced phase angle read from the phase angle table 67. Get closer.
Further, in the case of this embodiment, the advance phase angle correction calculating section 6
Since the advanced phase angle after correction may become too large depending on the correction amount obtained in step 8, the excessively advanced phase angle is limited by the advanced phase angle limiting unit 70, and the driving of the brushless DC motor 4 without inconvenience is achieved. I do.

As is apparent from the above description, since the advance phase angle read from the advance phase angle table 67 is corrected, the advance phase angle table 67
Even if the content of
Control based on the leading phase angle without error can be achieved.

[0063]

Embodiment 4 FIG. 16 is a block diagram showing still another embodiment of the brushless DC motor driving apparatus according to the present invention.
The difference from the embodiment of FIG.
Are omitted, and the advance phase angle correction calculation unit 68 receives the rotation speed deviation calculated by the rotation speed deviation calculation unit 64 and the determination result from the current droop necessity determination unit 62 as inputs and corrects the advance phase angle. The only difference is that a device for calculating the amount is employed.

Therefore, in the case of this embodiment, in addition to the operation of the third embodiment, when the current drooping is necessary, the leading phase angle correction calculating section 68 calculates the negative leading phase correction amount, and Can be reduced, and the fact that the current droop is required in the PWM control unit 66 without passing through the PI control unit 65 can be reflected, so that the PWM control when the current droop is required can be performed at high speed. And can be achieved with high accuracy.

[0065]

Embodiment 5 FIG. 17 is a block diagram showing still another embodiment of the brushless DC motor driving apparatus according to the present invention.
The difference from the embodiment of FIG.
8, the only difference is that a correction value for the phase angle is calculated by using the rotation speed deviation calculated by the rotation speed deviation calculation unit 64 and the input current detection signal from the input current detection unit 61 as inputs.

Therefore, in the case of this embodiment, in addition to the operation of the third embodiment, when the deviation of the rotation speed calculated by the rotation speed deviation calculation section 64 is almost zero, the current flowing through the converter 2 is minimized. And the phase angle can be corrected so that the brushless DC motor 4 can be operated with higher efficiency.

[0067]

Embodiment 6 FIG. 18 is a block diagram showing still another embodiment of the brushless DC motor driving apparatus according to the present invention.
A DC voltage is obtained by supplying the AC power supply 1 to the converter 2, and a three-phase AC voltage is obtained by supplying the AC power supply 1 to the inverter 3, and is supplied to the armature winding of the brushless DC motor 4 for driving the compressor 4 a. are doing. Then, the input current detection unit 61 detects the current flowing through the converter 2, and the current droop necessity determination unit 62 compares the detected input current with a predetermined reference current to determine whether the current droop is necessary. The rotation speed command is reduced by the rotation speed command reduction unit 63 based on the determination result indicating that the current droop is necessary. Further, an output voltage is calculated by the output voltage calculation unit 71 based on the rotation speed command reduced by the rotation speed command reduction unit 63 and the energizing current in the inverter 3, and a plurality of advance phase angles are determined in advance based on the rotation speed command. The corresponding advance phase angle is read from the stored advance phase angle table 67, the output voltage is corrected by the output voltage correction calculation unit 72, a voltage command is obtained, and supplied to the PWM control unit 66. This PWM control unit 66 supplies a switching command determined based on the voltage command to the inverter 3.

The operation of the brushless DC motor driving device having the above configuration is as follows. Since the rotation speed command is supplied to the output voltage calculation unit 71 via the rotation speed command reduction unit 63, the rotation speed command is directly used as the output voltage calculation unit 71 when the current flowing through the converter 2 is not excessive.
When the current flowing through the converter 2 is excessive, a new rotation speed command obtained by reducing the rotation speed command is supplied to the output voltage calculation unit 71. Since the current flowing through the inverter 3 is also supplied to the output voltage calculation unit 71, the rotation of the brushless DC motor 4 is controlled by controlling the calculation of the output voltage by the output voltage calculation unit 71 based on the current flow. An output voltage calculation result based on the estimated position of the child can be obtained. In addition, the rotational speed command can be supplied to the advanced phase angle table 67 to read the advanced phase angle corresponding to the rotational speed command, and supplied to the output voltage correction calculator 72 together with the output voltage calculation result. The output voltage correction calculation unit 72 calculates a voltage command to advance the phase of the output voltage of the inverter 3 by a predetermined phase angle from the phase of the induced voltage of the brushless DC motor 4 by the read advance phase angle. Therefore, a switching command is given to the inverter 3 to advance the phase of the output voltage of the inverter 3 by a predetermined phase angle with respect to the phase of the induced voltage of the brushless DC motor 4. it can.

As is apparent from the above description, the rotational position detecting section 51 and the rotational speed calculating section 52 for detecting the estimated rotational position of the armature of the brushless DC motor 4 can be omitted. The output voltage calculation unit 71 is controlled based on the current flowing through the inverter 3 to achieve processing equivalent to processing based on detection of the estimated rotational position of the rotor. As a result, the induced voltage of the brushless DC motor 4 is reduced. Therefore, the operation range of the brushless DC motor 4 can be expanded.

[0070]

Embodiment 7 FIG. 19 is a block diagram showing still another embodiment of the brushless DC motor driving apparatus according to the present invention.
18 is different from the embodiment of FIG. 18 in that a difference between the rotation speed command and the output frequency of the inverter 3 is calculated and the rotation speed deviation calculation unit 73 outputs the difference as a rotation speed deviation. A leading phase angle correction calculating unit 68 for calculating a correction amount; a leading phase angle correction unit 69 for correcting a leading phase angle read from the leading phase angle table 67 based on the calculated correction amount; The only difference is that it further includes a leading phase angle limiting unit 70 that limits the leading phase angle so as not to exceed a predetermined limit leading phase angle and supplies it to the output voltage correction calculation unit 72.

Therefore, in the case of this embodiment, when the rotational speed command is higher than the actual rotational speed, a correction is made to increase the advanced phase angle read from the advanced phase angle table 67, and conversely, When the rotation speed command is equal to or less than the actual rotation speed, the correction amount output from the advance phase angle correction calculation unit 68 is reduced, and the advanced phase angle after correction is changed to the advanced phase angle read from the phase angle table 67. Get closer.
Further, in the case of this embodiment, the advance phase angle correction calculating section 6
Since the advanced phase angle after correction may become too large depending on the correction amount obtained in step 8, the excessively advanced phase angle is limited by the advanced phase angle limiting unit 70, and the driving of the brushless DC motor 4 without inconvenience is achieved. I do.

As is clear from the above description, since the advance phase angle read from the advance phase angle table 67 is corrected, the advance phase angle table 67
Even if the content of
Control based on the leading phase angle without error can be achieved.

[0073]

Eighth Embodiment FIG. 20 is a block diagram showing still another embodiment of the brushless DC motor driving apparatus according to the present invention.
The difference from the embodiment of FIG.
Are omitted, and the advance phase angle correction calculation unit 68 receives the rotation speed deviation calculated by the rotation speed deviation calculation unit 73 and the determination result from the current droop necessity determination unit 62 as input and corrects the advance phase angle. The only difference is that a device for calculating the amount is employed.

Therefore, in this embodiment, in addition to the operation of the seventh embodiment, when the current drooping is required, the leading phase angle correction calculating section 68 calculates the negative leading phase correction amount, and Can be reduced, and the fact that the current droop is required in the output voltage correction calculation unit 72 without passing through the output voltage calculation unit 71 can be reflected. Can be achieved quickly and accurately.

[0075]

Embodiment 9 FIG. 21 is a block diagram showing still another embodiment of the brushless DC motor driving apparatus according to the present invention.
The difference from the embodiment of FIG.
No. 8 is only the point that the deviation of the rotation speed calculated by the rotation speed deviation calculation unit 73 and the input current detection signal from the input current detection unit 61 are input and the correction amount for the phase angle is calculated.

Therefore, in this embodiment, in addition to the operation of the seventh embodiment, when the deviation of the rotation speed calculated by the rotation speed deviation calculation unit 73 is almost 0, the current flowing through the converter 2 is minimized. And the phase angle can be corrected so that the brushless DC motor 4 can be operated with higher efficiency. Note that the present invention is not limited to the above embodiment. For example, the phase of the armature current or the phase of the output voltage of the inverter 3 may be set as long as the current in the direct axis direction of the armature current can be made negative. Can be applied to a method other than the method of advancing the phase of the induced voltage, and it can be applied to a brushless DC motor that drives a load other than the compressor. In addition, the gist of the present invention is changed. Various design changes can be made within a range not to be performed.

[0077]

As described above, according to the first aspect of the present invention, the induced voltage can be reduced only by making the phase of the armature current advance from the induced voltage by the inverter, and as a result, high speed rotation can be achieved. To play. The invention of claim 2 is
Since the permanent magnet is embedded in the rotor core and the inductance is set to be large, the induced voltage can be greatly reduced, and as a result, a specific effect that higher speed rotation can be achieved is achieved.

According to a third aspect of the present invention, in addition to the effects of the first or second aspect, the rated speed of the compressor can be set to 60% or more of the maximum speed by the conventional control, and the efficiency of driving the compressor is increased. Is achieved. According to the invention of claim 4, the induced voltage can be reduced only by making the phase of the armature current advance from the induced voltage by the inverter.
This has a specific effect that high-speed rotation can be achieved.

According to a fifth aspect of the present invention, a predetermined advance phase angle corresponding to the rotation speed of the brushless DC motor is output from the advance phase angle holding means, and the switching is performed in consideration of the output advance phase angle. By outputting the switching command from the command output means and supplying it to the inverter, the phase of the armature current of the brushless DC motor can be advanced more than the induced voltage to reduce the induced voltage, and as a result, high speed rotation can be achieved. Has the effect of

According to a sixth aspect of the present invention, even if the advanced phase angle held by the advanced phase angle holding means is not accurate, the advanced phase angle corrected by the advanced phase angle correction means and limited as necessary. By outputting the switching command from the switching command output unit in consideration of the angle and supplying the switching command to the inverter, the phase of the armature current of the brushless DC motor can be advanced from the induced voltage to reduce the induced voltage. This has a specific effect that high-speed rotation can be achieved.

According to the seventh aspect of the present invention, in addition to the effect of the sixth aspect, when it is determined that the current droop is necessary, correction is performed by the advanced phase angle correcting means so that the advanced phase angle is reduced. This has a unique effect that current droop can be achieved at high speed and with high accuracy. According to the invention of claim 8, in addition to the effect of claim 6, the current droop can be achieved at high speed and with high accuracy by correcting the rotational speed command to be lowered based on the determination result indicating that the current droop is necessary. ,
Since the advance phase angle is also corrected based on the converter energizing current, the inverter control is performed to minimize the converter energizing current, thereby achieving a unique effect that a more highly efficient drive of the brushless DC motor can be achieved.

According to a ninth aspect of the present invention, the switching command output means outputs a predetermined advance phase angle corresponding to the rotational speed command from the advance phase angle holding means, and also considers the output advance phase angle. By outputting a switching command to the inverter and supplying it to the inverter, the phase of the armature current of the brushless DC motor can be advanced from the induced voltage to reduce the induced voltage. As a result, high-speed rotation can be achieved.
Since a mechanism for detecting the rotational position and rotational speed of the rotor, an electric circuit, and the like can be dispensed with, a unique effect that the configuration can be simplified can be achieved.

According to a tenth aspect of the present invention, even if the advanced phase angle held by the advanced phase angle holding means is not accurate, the advanced phase angle corrected by the advanced phase angle correction means and limited as required. By outputting the switching command from the switching command output unit in consideration of the angle and supplying the switching command to the inverter, the phase of the armature current of the brushless DC motor can be advanced from the induced voltage to reduce the induced voltage. Since a high-speed rotation can be achieved, and a mechanism for detecting the rotational position and the rotational speed of the rotor, an electric circuit, and the like can be eliminated, a unique effect that the configuration can be simplified can be achieved.

According to the eleventh aspect of the present invention, in addition to the effect of the tenth aspect, when it is determined that the current droop is necessary, the correction is performed by the advanced phase angle correcting means so that the advanced phase angle is reduced. This has a unique effect that current droop can be achieved at high speed and with high accuracy. According to the twelfth aspect of the present invention, in addition to the effect of the tenth aspect, the current droop can be achieved at high speed and with high accuracy by correcting the rotational speed command to be lowered based on the determination result indicating that the current droop is necessary. Since the advance phase angle is also corrected on the basis of the converter energizing current, inverter control is performed to minimize the converter energizing current, thereby achieving a unique effect that a more efficient brushless DC motor can be driven.

According to the thirteenth aspect of the present invention, since the permanent magnet is embedded in the rotor core and the inductance is set large, the induced voltage can be greatly reduced, and as a result, higher speed rotation can be achieved. It works. Claim 1
According to the invention of claim 4, in addition to the effect of any one of claims 4 to 13, the rated speed is set to 60 times the maximum speed by the conventional control.
%, And achieves a unique effect that high efficiency of compressor drive can be achieved.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing an embodiment of a brushless DC motor control device according to the present invention.

FIG. 2 shows a brushless D to which the control method of the present invention is applied.
FIG. 3 is a schematic longitudinal sectional view illustrating an example of a configuration of a C motor.

FIG. 3 is a brushless D to which the control method of the present invention is applied.
FIG. 9 is a schematic vertical sectional view showing another configuration example of the C motor.

FIG. 4 shows a case where id = 0 control is applied to a brushless DC motor having a permanent magnet disposed on the surface of a rotor.
When id <0 control is applied, id <0 is applied to a brushless DC motor having a permanent magnet embedded inside the rotor.
FIG. 9 is a diagram illustrating a change in torque with respect to the number of rotations when control is applied.

FIG. 5 is a diagram showing a change in air gap magnetic flux density equivalent to one corresponding to a rotation position of a rotor of a brushless DC motor having a rotor having a skew angle of 0 °.

FIG. 6 is a schematic longitudinal sectional view showing an example of a rotor capable of setting a large skew angle.

FIG. 7 is a schematic vertical sectional view showing another example of a rotor capable of setting a large skew angle.

FIG. 8 is a perspective view showing a specific example in which a rotor core is divided into five parts.

FIG. 9 is a diagram showing each division unit in the specific example of FIG. 8;

FIG. 10 is a diagram showing a change in air gap magnetic flux density corresponding to one corresponding to a rotational position of a rotor in the specific example of FIG. 8;

FIG. 11 is a schematic longitudinal sectional view showing still another example of the configuration of the brushless DC motor to which the control method of the present invention is applied.

FIG. 12 is a schematic vertical sectional view showing another configuration example of the brushless DC motor to which the control method of the present invention is applied.

FIG. 13 is a block diagram showing another embodiment of the brushless DC motor driving device of the present invention.

FIG. 14 is a schematic diagram showing a relationship between an advance phase angle and a rotation speed stored in advance in an advance phase angle table.

FIG. 15 is a block diagram showing another embodiment of the brushless DC motor driving device of the present invention.

FIG. 16 is a block diagram showing another embodiment of the brushless DC motor driving device of the present invention.

FIG. 17 is a block diagram showing another embodiment of the brushless DC motor driving device of the present invention.

FIG. 18 is a block diagram showing another embodiment of the brushless DC motor driving device of the present invention.

FIG. 19 is a block diagram showing another embodiment of the brushless DC motor driving device of the present invention.

FIG. 20 is a block diagram showing another embodiment of the brushless DC motor driving device of the present invention.

FIG. 21 is a block diagram showing another embodiment of the brushless DC motor driving device of the present invention.

FIG. 22 is a diagram illustrating characteristics of a brushless DC motor having a rotor in which a permanent magnet is attached to the periphery of a rotor core.

FIG. 23 is a diagram illustrating characteristics of the brushless DC motor when the maximum rotation speed is set high.

FIG. 24 is a diagram showing the efficiency of a brushless DC motor corresponding to a change in the number of rotations.

[Explanation of symbols]

3 Inverter 4 Brushless DC motor 6
Inverter controller 41 Armature 42 Rotor 42a Rotor core 42b Permanent magnet 51 Rotational position detector 52 Rotational speed calculator 6
Reference Signs List 1 input current detection unit 62 current droop necessity determination unit 63 rotation speed command reduction unit 66 PWM control unit 67 advance phase angle table 68 advance phase angle correction calculation unit 69 advance phase angle correction unit 70 advance phase angle limit unit 71 output voltage calculation Unit 72 Output voltage correction calculation unit 73 Rotation speed deviation calculation unit

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A 1-248987 (JP, A) JP-A 3-215184 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02P 6/00

Claims (14)

(57) [Claims] A permanent magnet (42) is attached to a rotor core (42a).
b) a brushless D having a rotor (42) provided with an armature (41) provided with a three-phase winding on an armature core;
A driving method for controlling a three-phase alternating current supplied to the three-phase winding of a C motor (4) by an inverter (3),
A method of driving a brushless DC motor, comprising controlling an output current or a voltage of an inverter (3) so as to advance a phase of an armature current of the brushless DC motor (4) beyond an induced voltage. 2. The brushless DC motor drive according to claim 1, wherein the brushless DC motor (4) has a rotor (42) in which a permanent magnet (42b) is embedded in a rotor core (42a). Method. 3. The brushless DC motor driving method according to claim 1, wherein the brushless DC motor (4) drives a compressor. 4. A permanent magnet (42) is attached to a rotor core (42a).
b) a brushless D having a rotor (42) provided with an armature (41) provided with a three-phase winding on an armature core;
A drive device for controlling a three-phase alternating current supplied to the three-phase winding of a C motor (4) by an inverter (3),
A brushless DC motor driving device including inverter control means (6) for controlling an output current or voltage of an inverter (3) so as to advance a phase of an armature current of the brushless DC motor (4) beyond an induced voltage. . 5. Inverter control means (6) for detecting a rotational position and a rotational speed of a rotor of a brushless DC motor (4).
Leading phase angle holding means (67) for outputting a leading phase angle corresponding to the rotation speed of the brushless DC motor (4);
A switching command output means (66) for outputting a switching command to be supplied to the inverter (3) with a voltage command determined based on a rotation speed command for the brushless DC motor (4) and the output advance phase angle as inputs. The brushless DC motor driving device according to claim 4. 6. Inverter control means (6) for detecting a rotational position and a rotational speed of a rotor of a brushless DC motor (4).
Leading phase angle holding means (67) for outputting a leading phase angle corresponding to the rotation speed of the brushless DC motor (4);
Advanced phase angle correction means (68) and (69) for correcting the output advanced phase angle based on the deviation of the actual rotational speed with respect to the rotational speed command, wherein the corrected advanced phase angle exceeds a predetermined advanced phase angle A leading phase angle limiting means (70) for limiting the voltage command and a voltage command determined based on a rotational speed command for the brushless DC motor (4);
5. The brushless DC motor driving device according to claim 4, further comprising switching command output means (66) for outputting a switching command to be supplied to the inverter (3) with the limited advance phase angle as input. . 7. A current drooping necessity judging means (6) for judging the necessity of current droop based on the current flowing through the converter (2).
1) In addition to (62), the advance phase angle correcting means (68) (69) outputs the advance based on the deviation of the actual rotational speed with respect to the rotational speed command and the result of the current droop necessity determination. 7. The brushless DC motor driving device according to claim 6, which corrects a phase angle. 8. A rotation speed command correcting means (61), (62), (63) for determining whether current droop is necessary or not based on the current flowing through the converter (2) and correcting the rotation speed command. , Advanced phase angle correction means (68) (6)
9. The brushless DC motor drive device according to claim 6, wherein the output phase correction is performed based on a deviation of an actual rotation speed with respect to the rotation speed command and a current supplied to the converter. 9. An inverter control means (6) for outputting a leading phase angle corresponding to a rotor speed command, a leading phase angle holding means (67), and a voltage command determined based on the rotating speed command and an output leading. The brushless DC motor driving device according to claim 4, further comprising switching command output means (66) and (72) for outputting a switching command to be supplied to the inverter (3) with the phase angle as an input. 10. An inverter control means (6) for determining a leading phase angle holding means (67) for outputting a leading phase angle corresponding to a rotation speed command, and an output frequency of the inverter (3) for the rotation speed command. Advanced phase angle correction means (68), (69), and (73) for correcting the output advanced phase angle based on the deviation of the rotational speed; and preventing the corrected advanced phase angle from exceeding a predetermined advanced phase angle. Leading phase angle limiting means (70) for restricting, and switching command output means for outputting a switching command to be supplied to the inverter (3) with the rotational speed command and the corrected and limited advanced phase angle as required as inputs. (66) (71) (7
5. The brushless DC motor driving device according to claim 4, comprising: 11. A current drooping necessity judging means (61) (62) for judging necessity of current droop based on a current flowing through the converter (2), and a lead phase angle correcting means (68). (69) and (73) correct the output leading phase angle based on the deviation of the rotation speed determined based on the output frequency of the inverter (3) with respect to the rotation speed command and the result of the necessity determination of the current droop. The brushless DC motor driving device according to claim 10. 12. A rotating speed command correcting means (61), (62), (63) for determining whether or not current droop is necessary based on the current flowing through the converter (2) and correcting the rotating speed command. Lead phase angle correction means (68)
(69) and (73) correct the output leading phase angle based on the rotation speed deviation determined based on the output frequency of the inverter (3) with respect to the rotation speed command and the energizing current of the converter (2). The brushless DC motor driving device according to claim 10. 13. A brushless DC motor (4) having a rotor (42) having a permanent magnet (42b) embedded in a rotor core (42a).
A brushless DC motor driving device according to any one of the above. 14. The brushless DC motor driving device according to claim 4, wherein the brushless DC motor (4) drives a compressor.