JP6790760B2 - Variable flux motor current control method and current control device - Google Patents

Description

The present invention relates to a current control method for a variable magnetic flux motor and a current control device.

Conventionally, in a permanent magnet synchronous motor having two or more permanent magnets having different holding forces in a rotor, the induced voltage is measured during operation of the permanent magnet synchronous motor, and the magnetic flux of the permanent magnet is estimated based on the measured induced voltage. However, a technique for stabilizing the current controllability of a permanent magnet synchronous motor by changing the control gain based on the estimated magnetic flux is disclosed (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2005-304204

Here, when calculating the estimated value of the magnet magnetic flux, the inductance value is used as a parameter of the calculation formula. In the permanent magnet synchronous motor of Patent Document 1, only the magnet magnetic flux changes, so that the magnet magnetic flux can be estimated using a fixed inductance value.

However, in a variable magnetic flux motor equipped with a permanent magnet that can change the amount of magnetization according to the current applied to the stator winding, not only the magnet magnetic flux but also the inductance changes significantly, control for stabilizing the current controllability. An estimated value of inductance is also required when adjusting the gain, but the estimation method has not been reported.

An object of the present invention is to provide a current control method capable of estimating the inductance of a variable magnetic flux motor in which the magnet magnetic flux and the inductance change and adjusting the control gain based on the estimated inductance.

The current control method for a variable magnetic flux motor according to the present invention includes a stator having a stator winding and a rotor having a plurality of permanent magnets, and a current applied from the inverter to the stator winding is formed. This is a current control method for a variable magnetic flux motor that can change the magnetizing rate of the permanent magnet by the action of a magnetic field. The q current command value for generating the current supplied to the stator windings to the inverter, and the q-axis PI control. The q-axis voltage command value given to the inverter is calculated based on the gain, and the d-current command value for generating the current supplied to the stator winding to the inverter, and the d-axis PI control gain are used for the inverter. The d-axis voltage command value to be given to is calculated, the q-axis inductance is estimated based on the q-axis current command value, and the rotation speed of the variable magnetic flux motor is obtained. Then, the d-axis inductance is estimated based on the d-axis current command value, the q-axis current command value, the d-axis voltage command value, the rotation speed, the estimated q-axis inductance, and the previous estimated value of the d-axis inductance. Then, the d-axis PI control gain is adjusted according to the estimated d-axis inductance, and the q-axis current and d-axis current corresponding to the q-axis voltage command value and the d-axis voltage command value are coiled from the inverter. Supply to. Further, the magnetizing d-axis current command value and the magnetizing q-axis current command value for changing the magnetizing rate of the permanent magnet are calculated based on the magnetizing rate command value, and the magnetizing d-axis current command value and the magnetizing The magnetizing PI control gain is calculated according to the magnetic q-axis current command value, and when changing the magnetizing rate of the permanent magnet, the current control using the d-axis PI control gain and the q-axis PI control gain is used. , Switch to current control using the magnetizing PI control gain.

According to the present invention, the inductance of the variable magnetic flux motor in which the magnet magnetic flux and the inductance change can be estimated, and the control gain can be adjusted based on the estimated value of the inductance, so that the control stability can be improved. ..

FIG. 1 is a control block diagram of the current control device of the variable magnetic flux type rotary electric machine of the first embodiment. FIG. 2 is a diagram for explaining a method of adjusting the PI control gain. FIG. 3 is a control block diagram of the current control device of the variable magnetic flux type rotary electric machine of the second embodiment. FIG. 4 is a diagram illustrating linear interpolation of the q-axis inductance Lq. FIG. 5 is a diagram for explaining nonlinear interpolation of the q-axis inductance Lq. FIG. 6 is a diagram showing the rate of change of the magnet magnetic flux with respect to the q-axis current, and is a diagram for explaining the execution timing of the initialization sequence. FIG. 7 is a diagram showing the rate of change of the magnet magnetic flux with respect to the q-axis current, and is a diagram for explaining the execution timing of the initialization sequence. FIG. 8 is a diagram illustrating an upper limit value of the d-axis inductance Ld. FIG. 9 is a diagram for explaining the lower limit value of the d-axis inductance Ld. FIG. 10 is a diagram illustrating a maximum value of PI control gain. FIG. 11 is a floater showing the flow of the initialization sequence. FIG. 12 is a control block diagram of the current control device for the variable magnetic flux motor of the sixth embodiment. FIG. 13 is a diagram showing the followability of the actual current with respect to the magnetizing d-axis current command value before and after adjusting the magnetizing PI control gain. FIG. 14 is a diagram showing the followability of the actual current with respect to the magnetizing d-axis current command value before and after adjusting the time change rate of the magnetizing d-axis current command value.

[First Embodiment]
FIG. 1 is a control block diagram showing a configuration of a current control device 100 (hereinafter, simply referred to as a current control device 100) of the variable magnetic flux type rotary electric machine according to the first embodiment. The current control device 100 of the present embodiment includes a q-axis PI controller 101, a d-axis PI controller 102, a q-axis inductance estimator 103, a d-axis inductance estimator 104, and a q-axis PI control gain adjuster 105. The d-axis gain adjuster 106, the d-axis gain (N + 1) estimator 107, the rotation speed estimator 108, the inverter 109, the q-axis subtractor 111, and the d-axis subtractor 112 are provided, and the variable magnetic flux is provided. This is a current control device that controls the motor 110.

However, among the above configurations included in the current control device 100, each configuration other than the inverter 109 is provided with one or a plurality of controllers as functional units, and is programmed to execute each function described later. Although the inverter 109 and the variable magnetic flux motor 110 are shown separately for convenience of explanation, they are actually one.

First, the variable magnetic flux motor 110 will be described. In the variable magnetic flux motor 110 (hereinafter, also simply referred to as the motor 110) which is the control target of the present invention, the amount of magnetization of the permanent magnet (low coercive magnet) included in the rotor is changed to the current applied from the inverter to the motor 110. It is configured to be changeable according to the situation. More specifically, the motor 110 is composed of a stator having a stator winding and a rotor having a plurality of permanent magnets, and a current applied from the inverter 109 to the stator winding is formed. By changing the magnetizing amount (magnetization rate) of the permanent magnet by the action of the magnetic field, the magnetic force (magnetic flux) of the permanent magnet itself can be changed. Therefore, by controlling the magnetic force of the permanent magnet according to the operating state (operating point) of the motor, the efficiency of the motor in a wide operating range can be improved. The control method for changing the magnetizing amount of the permanent magnet will be described later with reference to FIG.

When the variable magnetic flux motor as described above is current-controlled, if the control gain of the current control is constant, the current does not follow the change of the operating point, and the control becomes unstable.

Here, in the current control of the motor, as described above in the background technique, a gain adjusting technique in the motor in which only the magnetic flux of the magnet changes is known. However, a gain adjustment technique for a motor in which both the magnetic flux of a magnet and the inductance change has not been reported prior to the present invention.

The present invention stabilizes the current controllability of a motor in which the magnet magnetic flux and the inductance change by estimating the inductance of the motor in which the magnet magnetic flux and the inductance change and adjusting the control gain based on the estimated inductance. Providing technology that can be used. Hereinafter, the description will be continued by returning to FIG.

The q-axis subtractor 111 subtracts the q-axis current detection value Iq (N-1) acquired from the three-phase alternating current input to the variable magnetic flux motor 110 from the q-axis current command value Iq ^* (N). The q-axis current command value Iq ^* , together with the d-axis current command value Id ^* described later, is a current (q-axis current Iq) supplied to the stator winding of the motor 110 in order to output a desired torque to the motor 110. It is a value set by a current command value setting means (not shown) to be generated in the inverter 109. The current command value setting means may have a configuration in which the above controller is provided as one functional unit in the same manner as each configuration of the current control device 100, or a controller different from the controller having each configuration of the current control device 100. It may be a functional unit provided in. The output value of the q-axis subtractor 111 is output to the q-axis PI controller 101.

Note that the detection, calculation, or estimation of each value used in the current control device described here is performed at regular intervals during system startup. The value (N) at the end of the values shown below indicates the value at the current control timing, and (N-1) indicates the value at the previous control timing (previous value).

The q-axis PI controller 101 is subjected to proportional integration (PI) control calculation from the input output value of the q-axis subtractor 111 and the q-axis PI control gain input from the q-axis PI control gain adjuster 105 described later. The q-axis voltage command value Vq ^* (N) is calculated and output to the inverter 109.

The d-axis subtractor 112 subtracts the d-axis current detection value Id (N-1) acquired from the three-phase alternating current input to the variable magnetic flux motor 110 from the current command value Id ^* (N). The d-axis current command value Id ^* , together with the q-axis current command value Iq ^* described above, is a current (d-axis current Id) supplied to the stator winding of the motor 110 in order to output a desired torque to the motor 110. It is a value set by a current command value setting means (not shown) to be generated in the inverter 109. The output value of the d-axis subtractor 112 is output to the d-axis PI controller 102.

The d-axis PI controller 102 is d-axis by proportional integration (PI) control calculation from the input current command value Id ^* and the d-axis PI control gain input from the d-axis gain (N + 1) estimator 107 described later. The voltage command value Vd ^* (N) is calculated and output to the inverter 109.

The q-axis inductance estimator 103 estimates the q-axis inductance Lq. Specifically, a map defining the relationship between the q-axis current and d-axis current and the q-axis inductance Lq is acquired in advance, and the q-axis current command value Iq ^* (N) and the d-axis current command value Id ^{* are obtained.} Based on (N), the q-axis inductance Lq is estimated by referring to the map. The estimated q-axis inductance Lq is input to the q-axis PI control gain adjuster 105.

The q-axis PI control gain adjuster 105 calculates the q-axis PI control gain according to the q-axis inductance Lq and outputs it to the q-axis PI controller 101. As shown in FIG. 2, for example, the q-axis PI control gain is calculated so as to increase as the q-axis inductance Lq increases.

The d-axis inductance estimator 104 estimates the d-axis inductance Ld. Specifically, according to the following equation (1) derived from the voltage equation, the d-axis voltage command value Vd ^* (N), which is the output value of the d-axis PI controller 102, and the output value of the rotation speed estimator 108. The motor rotation speed ω (N), the d-axis current command value Id ^* (N), the q-axis current command value Iq ^* (N), and the winding resistance Ra of the stator winding provided in the motor 110 acquired in advance. , The d-axis inductance Ld is estimated from the q-axis inductance Lq estimated by the q-axis inductance estimator 103 and the d-axis inductance Ld (N-1) estimated at the previous control timing. The estimated d-axis inductance Ld is output to the d-axis gain adjuster 106.

The d-axis gain adjuster 106 calculates the d-axis PI control gain according to the d-axis inductance Ld and outputs it to the d-axis gain (N + 1) estimator 107. As shown in FIG. 2, for example, the d-axis PI control gain is calculated so as to increase as the d-axis inductance Ld increases. As described above, according to the current control device 100 of the first embodiment, the d-axis inductance Ld can be estimated, and the d-axis PI control gain can be adjusted according to the estimated d-axis inductance Ld.

The d-axis gain (N + 1) estimator 107 estimates the d-axis PI control gain (N + 1) predicted to be calculated at the next control timing by the d-axis gain adjuster 106 from the d-axis PI control gain (N). To do. The calculated d-axis PI control gain (N + 1) is output to the d-axis PI controller 102. As a result, at the control timing following the timing at which the d-axis PI control gain (N + 1) is estimated, when the d-axis current command value Id ^* (N) is input to the d-axis PI controller 102, the d-axis voltage command is issued. The value Vd ^* (N) can be estimated more accurately. The method of estimating the value at the next control timing based on the current value or the transition from the past value to the current value is not particularly limited, and a known method may be used.

The rotation speed estimator 108 calculates the rotation speed ω (N) from the rotation speed ω (N-1) at the previous control timing calculated based on the detection values of rotation sensors such as resolvers and encoders (not shown). Estimate and output to the d-axis inductance estimator 104. As a result, in the d-axis inductance estimator 104, the delay element is eliminated, so that a more correct d-axis inductance Ld without delay can be estimated. The method of estimating the current value from the past value is not particularly limited, and a known method can be used in the same manner as in the case where the d-axis PI control gain (N + 1) is estimated by the d-axis gain (N + 1) estimator 107. Good.

Then, the inverter 109 has a q-axis current Iq corresponding to the q-axis voltage command value Vq ^* input from the q-axis PI controller 101 and a d-axis voltage command value Vd ^* input from the d-axis PI controller 102. The d-axis current Id corresponding to the above is output to the motor 110.

The above is the details of the current control in this embodiment. With such a control configuration, the PI control gain can be adjusted according to the operating point even in a variable magnetic flux motor in which both the d-axis inductance Ld and the magnet magnetic flux Ψa change. As a result, the current followability with the change of the operating point is improved, and the control stability of the current control can be improved, so that the efficiency of the motor 110 can be improved in a wide operating range.

As described above, the current control device 100 of the variable magnetic flux motor of the first embodiment includes a stator having a stator winding and a rotor having a plurality of permanent magnets, and is applied from the inverter to the stator winding. The current control device 100 realizes a current control method for a variable magnetic flux motor capable of changing the magnetizing rate of a permanent magnet by the action of a magnetic field formed by a current. The current control device 100 gives the q-axis voltage command value Vq to the inverter 109 based on the q-axis current command value Iq ^* for generating the current supplied to the stator winding to the inverter and the q-axis PI control gain. ^* is calculated, and the d-axis current command value Id ^* for generating the inverter 109 the current supplied to the stator windings, and the d-axis PI control gain, the d-axis voltage command value Vd to be applied to the inverter 109 based on the ^* Is calculated, the q-axis inductance Lq is estimated based on the q-axis current command value Iq ^*, and the rotation speed of the variable magnetic flux motor 110 is obtained. Then, the d-axis current command value Id ^{*, the} q-axis current command value Iq ^* , the d-axis voltage command value Vd ^* , the rotation speed, the estimated q-axis inductance Lq, and the previous estimated value of the d-axis inductance Ld (N). -1), the d-axis inductance Ld is estimated based on the above, and the d-axis PI control gain is adjusted according to the estimated d-axis inductance Ld, and the q-axis voltage command value Vq ^* and the d-axis voltage command value Vd ^* The q-axis current Iq and the d-axis current Id corresponding to the above are supplied from the inductance 109 to the inductor winding.

As a result, the d-axis inductance Ld of the variable magnetic flux motor 110 in which the magnet magnetic flux and the inductance change can be estimated. Therefore, control stability is achieved by adjusting the PI control gain based on the estimated value of the d-axis inductance Ld. It is possible to improve the efficiency of the motor 110 in a wide operating range.

Further, according to the current control device 100 of the variable magnetic flux type rotary electric machine of the first embodiment, the q-axis inductance Lq stores the relationship between the d-axis current Id and the q-axis current Iq and the q-axis inductance Lq in advance. It is estimated from the q-axis current command value Iq ^* and the d-axis current command value Id ^* using a map. As a result, the q-axis inductance Lq can be estimated accurately.

[Second Embodiment]
The current control device 200 of the second embodiment mainly differs from the first embodiment in the method of estimating the q-axis inductance Lq.

FIG. 3 is a control block diagram showing the configuration of the current control device 200 of the second embodiment. The same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 3, unlike the first embodiment, the d-axis current command value Id ^* (N) is not input to the q-axis inductance estimator 223 of the present embodiment, and the q-axis current command value Iq ^* ( The q-axis inductance Lq is estimated from N).

Specifically, the q-axis inductance estimator 223 is an interpolation formula that interpolates between a predetermined maximum value Lq_max and a minimum value Lq_min of the q-axis inductance Lq based on the q-axis current command value iq ^* (N). Is used to calculate the q-axis inductance Lq. The interpolation formula is composed of a linear or non-linear function having a maximum value Lq_max and a minimum value Lq_min as coefficients, and any one of a plurality of patterns exemplified in FIGS. 4 and 5 is used.

FIG. 4 is a diagram illustrating a method of calculating the q-axis inductance Lq by linearly interpolating the maximum value Lq_max and the minimum value Lq_min. As shown in FIG. 4, in linear interpolation, the q-axis inductance Lq is calculated based on the linear function of the q-axis current Iq connecting two points of the maximum value Lq_max and the minimum value Lq_min with a straight line. As a result, unlike the q-axis inductance estimator 103 of the first embodiment, it is not necessary to store the map, so that the amount of memory used in the current control device 200 can be reduced.

5 (a) and 5 (b) are diagrams for explaining a method of calculating the q-axis inductance Lq by non-linearly interpolating the maximum value Lq_max and the minimum value Lq_min. As shown in FIGS. 5A and 5B, in the nonlinear interpolation, the q-axis inductance Lq is calculated based on the nonlinear function of the q-axis current Iq connecting the two points of the maximum value Lq_max and the minimum value Lq_min. To. The nonlinear interpolation formulas shown in FIGS. 5A and 5B are examples and are adjusted in advance according to the characteristics of the motor to be controlled. As a result, the amount of memory used in the current control device 200 can be reduced as compared with storing the map as in the q-axis inductance estimator 103 of the first embodiment.

As described above, according to the current control device 200 of the variable magnetic flux motor 110 of the second embodiment, the q-axis inductance Lq uses an interpolation formula that interpolates between a predetermined maximum value and minimum value of the q-axis inductance Lq. , Q-axis current command value Iq ^* . The interpolation is a linear or non-linear interpolation. As a result, it is not necessary to prepare a map that stores the relationship between the d-axis current Id and the q-axis current Iq and the q-axis inductance Lq, so that the amount of memory used by the current control device 200 can be reduced. it can.

[Third Embodiment]
The current control device 300 of the third embodiment uses the following equation (2) in which a fixed value Ld (0) is set as an initial value at the first control timing when estimating the d-axis inductance Ld. There is a feature. As the fixed value Ld (0) set as the initial value, a value acquired in advance according to the characteristics of the controlled motor is used.

The first control timing here is the first control timing after the vehicle is started, and the control system of the vehicle is started and the current is first applied to the stator winding provided in the motor 110. It refers to the control timing at that time.

Further, when resetting the d-axis inductance Ld estimated in the subsequent current control to the initial value, Ld (N) = Ld (0) is set by using the above fixed value Ld (0). In the following, resetting the d-axis inductance Ld estimated in the current control to the initial value is referred to as an initialization sequence.

This makes it possible to accurately estimate the d-axis inductance Ld from the start of the vehicle system in a motor in which both the d-axis inductance and the magnet magnetic flux change, so that the mode efficiency of the motor 110 can be further improved. Can be done.

Further, since the fixed value Ld (0) acquired in advance is used instead of calculating with reference to a map or the like, the amount of memory used in the current control device 300 can be reduced.

As described above, according to the current control device 300 of the variable magnetic flux motor 110 of the third embodiment, a predetermined fixed value Ld (0) is used as the initial value of the d-axis inductance Ld. As a result, in a motor in which both the magnetic flux of the magnet and the inductance change, the d-axis inductance Ld can be accurately estimated from the start of the vehicle system.

Further, according to the current control device 300 of the variable magnetic flux motor 110 of the third embodiment, when executing the initialization sequence for initializing the estimated d-axis inductance Ld, the estimated d-axis inductance Ld value is fixed. Set to Ld (0). As a result, the d-axis inductance Ld can be estimated more accurately in a motor in which both the magnetic flux of the magnet and the inductance change.

[Fourth Embodiment]
The current control device 400 of the fourth embodiment is different from the third embodiment in that the initial value Ld (0) is calculated during the current control. Hereinafter, the calculation method will be described with reference to figures and the like.

6 and 7 are diagrams showing the relationship between the q-axis current Iq and the d-axis magnetic flux λd when the d-axis current Id is substantially 0 in the motor 110. The dotted line in the figure shows the d-axis magnetic flux λd with respect to the q-axis current Iq in the motor 110 controlled by the present invention. The solid line in the figure is a normal motor characteristic that is not the subject of the present invention, and indicates a d-axis magnetic flux λd that does not change with respect to the q-axis current Iq. That is, in the motor 110, when the d-axis current Id is approximately 0, the magnet magnetic flux Ψa changes by approximately 10% or more due to the q-axis current Iq.

The calculation of the initial value Ld (0) in the present embodiment is performed when the rate of change dΨa / dId of the magnet magnetic flux with respect to the q-axis current Iq is approximately 0. More specifically, when the q-axis current Iq is approximately 0 (circled area in FIG. 6) or when the q-axis current Iq is near the maximum value (circled area in FIG. 7), such as when the vehicle is stopped. ), At least small currents Id1 (first d-axis current) and Id2 (second d-axis current) that can calculate the induced voltage generated in the stator winding are passed through the stator winding twice by pulse. , Get the induced voltage at that time. Then, when the d-axis magnetic fluxes λd1 and λd2 are obtained based on the acquired induced voltage, they can be expressed as the following equation (3). The induced voltage may be measured by a measuring instrument or calculated by a known method.

At this time, since the rate of change dΨa / dIq of the magnet magnetic flux Ψa with respect to the q-axis current Iq is approximately 0, the magnet magnetic flux Ψa can be regarded as a constant value. Therefore, the d-axis inductance Ld can be calculated from the equation (3). Then, the calculated d-axis inductance Ld is set to the initial value Ld (0). Further, in the present embodiment, the d-axis inductance Ld calculated based on the equation (3) is set as the initial value Ld (0) in the d-axis inductance Ld (N) even when the initialization sequence is executed. As a result, in a motor in which both the d-axis inductance and the magnet magnetic flux change, the d-axis inductance Ld can be estimated more accurately, and the mode efficiency of the motor 110 can be further improved.

Although the current phase is not considered in the relationship between the q-axis current Iq and the d-axis magnetic flux λd shown in FIGS. 6 and 7, the current phase also affects depending on the characteristics of the motor, so the current phase is considered. The rate of change of the magnet magnetic flux with respect to the q-axis current Iq may be calculated as dΨa / dId.

As described above, when the current control device 400 of the variable magnetic flux motor 110 of the fourth embodiment measures or calculates the induced voltage generated in the stator winding and executes the initialization sequence for initializing the estimated d-axis inductance Ld. Sets a value calculated based on the magnetic flux of the magnet obtained from the induced voltage as an initial value. As a result, the initial value is calculated during the operation of the motor 110, so that the d-axis inductance Ld can be estimated more accurately.

Further, the current control device 400 of the variable magnetic flux motor 110 of the fourth embodiment is initially used when the variable magnetic flux motor operates in an operating range in which the rate of change of the magnetic flux dψa / dIq with respect to the q-axis current Iq is approximately 0. Execute the conversion sequence. As a result, the initialization is executed at an appropriate timing during the operation of the motor 110, so that the d-axis inductance Ld can be continuously estimated more accurately.

Further, according to the current control device 400 of the variable magnetic flux motor 110 of the fourth embodiment, in the initialization sequence, when the q-axis current is substantially 0, the first d-axis current is passed through the stator winding. A value calculated based on the calculated d-axis magnetic flux λd1 and the d-axis magnetic flux λd2 calculated by passing a second d-axis current through the stator winding is set as an initial value. As a result, the initial value is calculated during the operation of the motor 110, so that the d-axis inductance Ld can be estimated more accurately.

Alternatively, according to the current control device 400 of the variable magnetic flux motor 110 of the fourth embodiment, in the initialization sequence, when the q-axis current is substantially the maximum value, the first d-axis current is passed through the stator winding. A value calculated based on the d-axis magnetic flux λd1 calculated by the above and the d-axis magnetic flux λd2 calculated by passing a second d-axis current through the stator winding is set as an initial value. As a result, the initial value is calculated during the operation of the motor 110, so that the d-axis inductance Ld can be estimated more accurately.

[Fifth Embodiment]
The current control device 500 of the fifth embodiment is different from each of the above-described embodiments in that the upper and lower limits are set between the estimated d-axis inductance Ld and the d-axis PI control gain calculated based on the d-axis inductance Ld. Is different. Hereinafter, description will be made with reference to figures and the like.

FIG. 8 is a diagram for explaining the upper limit value of the estimated d-axis inductance Ld. The upper limit value Ld_max of the d-axis inductance Ld is set in advance according to the motor characteristics. Then, when the estimated d-axis inductance Ld exceeds the upper limit value Ld_max, the estimated value of the d-axis inductance Ld is set to Ld_max. In other words, when Ld ≧ Ld_max, Ld = Ld_max.

FIG. 9 is a diagram for explaining the lower limit value of the estimated d-axis inductance Ld. The lower limit value Ld_min of the d-axis inductance Ld is set in advance according to the motor characteristics. Then, when the estimated d-axis inductance becomes the lower limit value Ld_min or less, the estimated value of the d-axis inductance Ld is set to Ld_min. In other words, when Ld ≦ Ld_min, Ld = Ld_min.

By setting the limit on the estimated value of the d-axis inductance Ld in this way, it is possible to prevent the current control from diverging in relation to the d-axis PI control gain.

Here, when the value of the d-axis inductance Ld becomes small, the rate of change of the current becomes large, so that the control is particularly easy to diverge. Therefore, even when the d-axis inductance Ld becomes Ld = Ld_min, the maximum gain value Gain_max at which control does not diverge is set in advance.

FIG. 10 is a diagram for explaining the maximum value of the d-axis PI control gain. When the d-axis PI control gain becomes equal to or higher than the maximum gain value Gain_max, the d-axis PI control gain is set to Gain_max. In other words, when the d-axis PI control gain ≥ Gain_max, the d-axis PI control gain = Gain_max. As a result, no matter how small the estimated d-axis inductance Ld becomes, it is possible to prevent the control from diverging.

Further, in the current control device 500 of the present embodiment, when the d-axis inductance Ld estimated as described above reaches the upper and lower limit values, the initialization sequence is executed at the timing that can be initialized next. For example, when the initialization sequence is executed using the initial value Ld (0) acquired in advance as described in the third embodiment, the motor after the estimated d-axis inductance Ld reaches the upper and lower limit values. It is executed at the timing when 110 is stopped. Further, when the initialization sequence is executed using the initial value Ld (0) calculated during the current control as described in the fourth embodiment, the estimated d-axis inductance Ld becomes the upper and lower limit values. After that, the execution is performed at the timing when the rate of change dΨa / dIq of the magnet magnetic flux with respect to the q-axis current Iq becomes substantially 0 (see FIGS. 6 and 7).

FIG. 11 is a flowchart illustrating the flow of the initialization sequence. The flow is programmed so that the controller provided with each configuration of the current control device 500 repeatedly executes the flow at predetermined intervals while the vehicle system is activated.

In step S1101, the d-axis inductance Ld is estimated.

In step S1102, it is determined whether or not the d-axis inductance estimated in step S1101 has reached the upper and lower limit values. When it is determined that the d-axis inductance is the upper limit value Ld_max or the lower limit value Ld_min, the process of step S1103 is executed in order to set the initialization flag to ON. If it is determined that the d-axis inductance is not the upper limit value Ld_max or the lower limit value Ld_min, the process of step S1104 following is executed to determine the state of the initialization flag.

In step S1103, the initialization flag indicating that the estimated value of the d-axis inductance Ld needs to be initialized is set to ON. Then, the process of step S1105 that follows is executed in order to determine whether the initialization sequence can be executed in the current flow.

In step S1104, it is determined whether or not the initialization flag is set to ON in the flow up to the previous time. If the d-axis inductance Ld reaches the upper and lower limit values even once, the estimation error may be large and the value cannot be trusted, so initialization needs to be performed. Therefore, even if the d-axis inductance Ld reaches the upper and lower limit values in the previous flow, if the initialization sequence is not executed, the initialization flag remains ON until the initialization is executed. If the initialization flag is set to ON, the process of step S1105 that follows is executed to determine whether the initialization sequence can be executed in the current flow. If the initialization flag is not set to ON, the initialization sequence execution flow related to this timing is terminated.

In step S1105, it is determined whether or not the initialization sequence can be executed. As described above, when the initialization sequence is executed using the initial value Ld (0) acquired in advance, it is determined whether or not the motor 110 has stopped. When the initialization sequence is executed using the initial value Ld (0) calculated during the current control, it is determined whether or not the rate of change dΨa / dIq of the magnet magnetic flux with respect to the q-axis current Iq is approximately 0. To. When the motor 110 is stopped, or when it is determined that the rate of change dΨa / dIq of the magnet magnetic flux with respect to the q-axis current Iq is substantially 0, the process of step S1106 for executing the initialization sequence is executed.

If the motor 110 is stopped or the rate of change dΨa / dId of the magnet magnetic flux with respect to the q-axis current Iq is not determined to be approximately 0, the current flow is not the timing to execute the initialization sequence. The initialization sequence execution flow related to the timing is terminated.

In step S1106, since it is determined that the timing can be initialized in the previous step, the initialization sequence is executed. After the initialization sequence is executed, the initialization flag is set to OFF in the subsequent processing of step S1107, and the process returns to step S1101 to estimate the d-axis inductance Ld again. By repeating the above flow while the vehicle control system is activated, the d-axis inductance Ld is monitored, and when the d-axis inductance Ld reaches the upper and lower limit values, initialization is executed. The accuracy of the d-axis inductance Ld is ensured. As a result, divergence of control can be prevented and current controllability is stabilized, so that mode efficiency can be improved.

As described above, in the current control device 500 of the variable magnetic flux motor 110 of the fifth embodiment, when the estimated d-axis inductance Ld is equal to or larger than the predetermined d-axis inductance upper limit value Ld_max, the d-axis inductance Ld is changed to the d-axis inductance upper limit value Ld_max. When the estimated d-axis inductance Ld is equal to or less than the predetermined d-axis inductance lower limit value Ld_min, the d-axis inductance Ld is set to the d-axis inductance lower limit value Ld_min. As a result, the upper and lower limits of the d-axis inductance Ld are set, so that it is possible to prevent the current control from diverging.

Further, the current control device 500 of the variable magnetic flux motor 110 of the fifth embodiment obtains the maximum gain at which the current control does not diverge even when the estimated d-axis PI control gain is the d-axis inductance lower limit value Ld_min. When the gain maximum value Gain_max or more is set in advance, the d-axis PI control gain is set to the gain maximum value Gain_max, whereby the divergence of the current control can be suppressed regardless of the value of the d-axis inductance Ld. Therefore, the current controllability can be made more stable.

Further, in the current control device 500 of the variable magnetic flux motor 110 of the fifth embodiment, when the d-axis inductance Ld is equal to or more than the d-axis inductance upper limit value Ld_max, or the d-axis inductance Ld is equal to or less than the d-axis inductance lower limit value, After that, the initialization sequence is executed when the rate of change dΨa / dIq of the magnet magnetic flux with respect to the q-axis current Iq first becomes approximately 0. In this way, when the d-axis inductance Ld reaches the upper and lower limit limits, the initialization sequence is executed at the next timing that can be initialized, and the error added in the integral calculation in PI control is reset. Therefore, the d-axis inductance Ld can be continuously estimated with high accuracy.

[Sixth Embodiment]
The current control device 600 of the variable magnetic flux motor 110 of the sixth embodiment executes a magnetic force control sequence that changes the magnetizing rate of the motor 110 by the action of a magnetic field generated by a current (winding current) applied to the stator windings. It is characterized by the fact that it does. Hereinafter, a configuration for executing the magnetic force control sequence and a method for adjusting the PI control gain (PI control gain for magnetizing) when the magnetic force control sequence is executed will be described with reference to figures and the like.

FIG. 12 is a control block diagram showing the configuration of the current control device 600 of the variable magnetic flux motor 110 according to the sixth embodiment.

A torque command value Tr ^* according to the operating state of the vehicle and an estimated magnetization amount Ψa of the magnet of the motor 110 estimated by the magnetic flux observer 24 are input to the magnetizing state holding control unit 11. Then, the magnetizing state holding control unit 11 is a d-axis containing a fundamental wave component for rotationally driving the motor 110 and a maintaining component necessary for maintaining the magnetizing rate of the magnet based on these input values. The current command value Id1 ^* and the q-axis current command value Iq1 ^* are calculated.

Then, the magnetized state holding control unit 11 outputs the d-axis current command value Id1 ^* to the d-axis calculator 12d, and outputs the q-axis current command value Iq1 ^* to the q-axis calculator 12q. Further, the magnetized state holding control unit 11 outputs the d-axis current command value Id1 ^* and the q-axis current command value Iq1 ^* to the non-interference control unit 15.

The d-axis current command value Id1 ^* and the d-axis current value Id of the motor 110 output from the three-phase-dq conversion unit 21 are input to the d-axis calculator 12d. Then, the d-axis calculator 12d calculates the d-axis current command value Id2 ^* by subtracting the d-axis current value Id from the d-axis current command value Id1 ^* . The d-axis calculator 12d outputs the d-axis current command value Id2 ^* to the PI-dq current controller 13.

Similarly, the q-axis current command value Iq1 ^* and the q-axis current value Iq of the motor 110 output from the three-phase −dq conversion unit 21 are input to the q-axis calculator 12q. Then, the q-axis calculator 12q calculates the q-axis current command value Iq2 ^* by subtracting the q-axis current value Iq from the q-axis current command value Iq1 ^* . The q-axis calculator 12q outputs the q-axis current command value Iq2 ^* to the PI-dq current controller 13.

The d-axis current command value Id2 ^* and the q-axis current command value Iq2 ^* are input to the PI-dq current controller 13. The PI-dq current controller 13 has been described in the first to fifth embodiments with the deviation between the command value and the measured value obtained during the calculation in the d-axis calculator 12d and the q-axis calculator 12q. From the PI control gain for current control (d-axis PI control gain, q-axis PI control gain) set in the same manner as in the above, the d-axis voltage command value vd1 and the q-axis voltage command value vq1 are calculated by the PI control calculation. .. Then, the PI-dq current controller 13 outputs the d-axis voltage command value vd1 to the d-axis adder 14d, and outputs the q-axis voltage command value vq1 to the q-axis adder 14q.

In addition to the d-axis voltage command value vd1 and the d-axis interference voltage command value vd'output from the non-interference control unit 15, the d-axis adder 14d receives the magnetism output from the magnetizing PI control unit 601. The magnetic d-axis voltage command value Vdm ^* is input. The d-axis adder 14d adds the d-axis voltage command value vd1, the d-axis interference voltage command value vd', and the magnetizing d-axis voltage command value Vdm ^*, and obtains the d-axis voltage command value vd which is the addition result. Output to the dq-3 phase conversion unit 16.

In addition to the q-axis voltage command value vq1 and the q-axis interference voltage command value vq'output from the non-interference control unit 15, the q-axis adder 14q receives the magnetism output from the magnetizing PI control unit 601. The magnetic q-axis voltage command value Vqm ^* is input. The q-axis adder 14q adds the q-axis voltage command value vq1, the q-axis interference voltage command value vq', and the magnetizing q-axis voltage command value Vqm ^*, and obtains the q-axis voltage command value vq which is the addition result. Output to the dq-3 phase conversion unit 16.

The non-interference control unit 15 suppresses interference between the d-axis current and the q-axis current based on the d-axis current command value Id1 ^* , the q-axis current command value Iq1 ^* , and the electric angular velocity ω of the motor 110. The d-axis interference voltage command value vd'and the q-axis interference voltage command value vq'are obtained. Then, the non-interference control unit 15 outputs the d-axis interference voltage command value vd'to the d-axis adder 14d, and outputs the q-axis interference voltage command value vq'to the q-axis adder 14q.

In addition to the d-axis voltage command value vd and the q-axis voltage command value vq, the rotor phase angle θ of the motor 110 output from the phase velocity calculation unit 22 is input to the dq-3 phase conversion unit 16. .. Then, the dq-3 phase conversion unit 16 calculates the three-phase voltage command values vu, vv, and vw based on the rotor phase angle θ with respect to the command value. Then, the dq-3 phase conversion unit 16 outputs the calculated three-phase voltage command values vu, vv, vw to the modulation rate calculation unit 17.

The modulation rate calculation unit 17 modifies the modulation used for generating the PWM signal based on the three-phase voltage command values vu, vv, vw and the DC voltage Vdc which is the reference voltage in the inverter 19 which generates the applied voltage to the motor 110. The rates mu, mv, and mw are calculated, and their modulation rates are output to the triangular wave comparison unit 18.

The triangular wave comparison unit 18 generates a PWM signal by comparing the input modulation factors mu, mv, mw with the triangular wave, and outputs the PWM signal to the inverter 19.

The inverter 19 generates a three-phase AC signal from a DC voltage by controlling a switch circuit (not shown) including an upper arm and a lower arm based on the PWM signal. Then, the inverter 19 outputs those three-phase AC signals to the motor 110. As a result, the motor 110 can be rotationally driven.

The current sensor 20 is provided between the inverter 19 and the motor 110, and measures the u-phase current Iu and the w-phase current Iw. Then, the current sensor 20 outputs the measured current value to the three-phase −dq conversion unit 21.

The u-phase current Iu and the w-phase current Iw are input to the three-phase-dq conversion unit 21, and the rotor phase angle θ is input from the phase velocity calculation unit 22. Then, the three-phase-dq conversion unit 21 calculates the d-axis current value Id, which indicates the current value flowing through the motor 110 on the dq axis, and the q-axis current value Iq, based on these inputs. Then, the three-phase-dq conversion unit 21 outputs the d-axis current value Id to the d-axis calculator 12d and outputs the q-axis current value Iq to the q-axis calculator 12q. At the same time, the three-phase-dq conversion unit 21 outputs the d-axis current value Id and the q-axis current value Iq to the inductance estimation unit 602, the magnetic flux observer 24, and the magnetizing PI control unit 601.

The phase velocity calculation unit 22 obtains the rotor phase angle θ of the motor 110 based on the signal detected by the rotation angle sensor 23 such as a resolver provided in the motor 110. The phase velocity calculation unit 22 outputs the rotor phase angle θ to the dq-3 phase conversion unit 16 and the three-phase −dq conversion unit 21. Further, the phase velocity calculation unit 22 obtains the electric angular velocity ω of the motor 110 by calculation, and outputs the obtained electric angular velocity ω to the magnetic flux observer 24.

In the magnetic flux observer 24, the d-axis current value Id, the q-axis current value Iq, and the electric angular velocity ω of the motor 110 are input. The magnetic flux observer 24 calculates the magnetized amount estimated value Ψa based on these inputs, and applies the calculated magnetized amount estimated value Ψa to the magnetizing state holding control unit 11 and the magnetizing PI control unit 601. Output. Here, the magnetized amount estimated value Ψa is an estimated value of the magnetized amount (magnetic flux number) representing the magnet magnetic flux Ψa of the magnet, and indicates the total number of magnetic fluxes interlinking with the magnetic flux generated by the stator coil. The value.

Specifically, the magnetic flux observer 24 stores the motor voltage equation in advance based on the d-axis current value Id, the q-axis current value Iq, and the electric angular velocity ω. Then, the magnetic flux observer 24 calculates the magnetized amount estimated value Ψa using the motor voltage equation.

The d-axis current value Id, the q-axis current value Iq, and the d-axis voltage command value vd are input to the inductance estimation unit 602. Then, the inductance estimation unit 602 uses the same method as the q-axis inductance estimator 103 and 223 and the d-axis inductance estimator 104 described in the first to fifth embodiments to perform the d-axis inductance Ld and the q-axis inductance Lq ( Collectively, these are also referred to as dq-axis inductance estimates). The dq-axis inductance estimated value is output to the magnetizing PI control unit 601.

A subtractor 27 is provided in front of the magnetizing PI control unit 601. In the subtractor 27, the magnetizing amount deviation ΔΨa is obtained by subtracting the magnetizing amount estimated value Ψa output from the magnetic flux observer 24 from the magnetizing amount command value Ψa ^* output from the host system (not shown). calculate. In the host system, a magnetizing amount command value Ψa ^* is required so that the magnetizing amount of the magnet is optimum according to the operating state.

The magnetizing amount deviation ΔΨa, the d-axis current value Id, the q-axis current value Iq, and the dq-axis inductance estimated value are input to the magnetizing PI control unit 601.

The magnetizing PI control unit 601 calculates the magnetizing d-axis current command value Idm ^* and the magnetizing q-axis current command value Iqm ^* according to the magnetizing amount deviation ΔΨa. Specifically, a map or a relational expression that defines the relationship between the magnetizing amount deviation ΔΨa and the magnetizing d-axis current command value Idm ^* and the magnetizing q-axis current command value Iqm ^* is stored in advance. By referring to the map or the relational expression, the magnetizing d-axis current command value Idm ^* and the magnetizing q-axis current command value Iqm ^* are generated from the input magnetism amount deviation ΔΨa.

Further, the magnetizing PI control unit 601 has the deviation between the generated magnetizing d-axis current command value Idm ^* and the d-axis current value Id, and the generated magnetizing q-axis current command value Iqm ^* and q-axis. The magnetizing current PI is controlled according to the deviation from the current value iq. As a result, from the magnetizing d-axis current command value Idm ^{*, the} magnetizing q-axis current command value Iqm ^*, and the magnetizing PI control gain described later, the magnetizing d-axis voltage command value Vdm ^* and the magnetizing q The shaft voltage command value Vqm ^* is calculated. The calculated d-axis voltage command value Vdm ^{* for} magnetism is output to the d-axis adder 14d, and the q-axis voltage command value Vqm ^* for magnetism is output to the q-axis adder 14q.

The magnetizing PI control gains used in this magnetizing current PI control are the magnetizing d-axis current command value Idm ^* and the magnetizing q-axis current command value Iqm ^* calculated from the magnetizing amount deviation ΔΨa. It is obtained by storing a map or relational expression that defines the relationship with the magnetizing PI control gain in advance and referring to the map or relational expression. When magnetizing the permanent magnet, the magnetizing PI is based on the current control performed by the PI-dq current controller 13 using the PI control gain (d-axis PI control gain, q-axis PI control gain). The control unit 601 switches to the current control performed by using the magnetizing PI control gain.

In this way, by adjusting the magnetizing PI control gain according to the deviation between the magnetizing amount command value Ψa ^* and the magnetizing amount estimated value Ψa, the magnetizing current (magnetic force control current) is transmitted to the motor 110. Before being energized, the current amplitude and phase of the magnetizing current can be determined. As a result, the PI control gain can be appropriately set according to the inductance that fluctuates depending on the current and the operating conditions of the motor.

Further, the magnetizing PI control unit 601 adjusts the magnetizing PI control gain according to the input dq-axis inductance estimated value. When the amount of magnetic flux is increased by magnetizing the permanent magnet included in the motor 110, the inductance tends to decrease due to magnetic saturation. When the inductance decreases, the current control tends to diverge. Therefore, by adjusting the magnetizing PI control gain according to the inductance, the followability of the actual current with respect to the magnetizing d-axis current command value Idm ^* and the magnetizing q-axis current command value Iqm ^* in current control. Is improved, so that the control stability can be further improved.

FIG. 13 is a diagram showing the followability of the actual current with respect to the magnetizing d-axis current command value Idm ^* before and after adjusting the magnetizing PI control gain. FIG. 13 (a) shows the followability of the actual current before adjusting the magnetizing PI control gain, and FIG. 13 (b) shows the followability of the actual current after adjusting the magnetizing PI control gain. Shown. The solid line in the figure represents the magnetizing d-axis current command value Idm ^* , and the dotted line represents the actual current (d-axis current). As shown in the figure, it can be seen that the followability of the actual current is improved by adjusting the magnetizing PI control gain.

In this way, by actively adjusting the magnetic field PI control gain according to the estimated dq-axis inductance value, it is possible to stably control the magnetic force even in a transient state where the operating conditions of the motor are changing. You can.

The magnetizing PI control unit 601 controls the magnetizing current PI using the magnetizing PI control gain adjusted as described above, thereby performing the magnetizing d-axis voltage command value Vdm ^* and the magnetizing q. Generates the shaft voltage command value Vqm ^* . The generated magnetizing d-axis voltage command value Vdm ^* is output to the d-axis adder 14d, and the magnetizing q-axis voltage command value Vqm ^* is output to the q-axis adder 14q.

Further, the magnetizing PI control unit 601 can also adjust the time change rate of the magnetizing d-axis current command value Idm ^* and the magnetizing q-axis current command value Iqm ^* . In current control, the responsiveness (followability) of the actual current to the current command value changes depending on the magnitude of the inductance. Therefore, the upper limit of the time change rate of the magnetizing d-axis current command value Idm ^* and the magnetizing q-axis current command value Iqm ^* is set according to the estimated dq-axis inductance value. For example, when the inductance is small and the current control is likely to diverge, the d-axis current command value for magnetism Idm ^* and the q-axis current command value for magnetization Iqm ^* can be raised by lowering the upper limit of the current change rate. Make it more gradual. As a result, it is possible to improve the followability of the actual current with respect to the magnetizing d-axis current command value Idm ^* and the magnetizing q-axis current command value Iqm ^* . This upper limit value is set to a current change rate within a range in which the actual current can follow the magnetizing d-axis current command value Idm ^* and the magnetizing q-axis current command value Iqm ^* .

Figure 14 is a diagram showing the followability of the actual current for magnetizing the d-axis current command value Idm ^* before and after adjusting the magnetizing d-axis current command value Idm ^* time rate of change of. FIG. 14 (a) shows the followability of the actual current before adjusting the time change rate of the magnetizing d-axis current command value Idm ^* , and FIG. 14 (b) shows the magnetizing d-axis current command value Idm. ^It shows the followability of the actual current after adjusting the time change rate of ^* . The solid line in the figure represents the magnetizing d-axis current command value Idm ^* , and the dotted line represents the actual current (d-axis current).

As shown, the magnetizing d-axis current command value Idm ^* rate of change is limited by adjusting the magnetizing d-axis current command value Idm ^* time rate of change of, magnetizing d-axis current command value Idm It can be seen that the followability of the actual current is improved because the rise and fall of ^* become gentle.

As described above, the current control device 600 of the variable magnetic flux motor 110 of the sixth embodiment has a magnetizing d-axis current command value Idm ^* for changing the magnetizing rate of the permanent magnet based on the magnetizing rate command value Ψa ^* and magnetizing. The q-axis current command value Iqm ^* for magnetism is calculated, and the PI control gain for magnetism is calculated according to the d-axis current command value Idm ^{* for} magnetism and the q-axis current command value Iqm ^* for magnetism. When changing the magnetizing rate of the permanent magnet, the current control using the d-axis PI control gain and the q-axis PI control gain is switched to the current control using the magnetizing PI control gain. .. As a result, when executing a magnetic force control sequence that requires a response different from that of normal current control, a PI control gain suitable for the magnetic force control sequence is selected, so that even when executing the magnetic force control sequence. The current can be controlled stably.

Further, the current control device 600 of the variable magnetic flux motor 110 of the sixth embodiment estimates the magnetizing rate of the permanent magnet, and the magnetizing PI control gain according to the magnetizing rate command value Ψa ^* and the magnetizing amount estimated value Ψa. To adjust. This makes it possible to appropriately set the PI control gain according to the inductance that fluctuates depending on the current and the operating conditions of the motor while the magnetic force control sequence is executed.

Further, the current control device 600 of the variable magnetic flux motor 110 of the sixth embodiment adjusts the magnetizing PI control gain according to the estimated d-axis inductance Ld and the estimated q-axis inductance Lq. .. As a result, even in a transient state in which the responsiveness of the current control changes according to the change in the inductance, the PI control gain for magnetizing can be changed according to the change in the inductance, so that the magnetic force control sequence is executed. During the period, magnetic force control can be performed stably.

Further, the current control device 600 of the variable magnetic flux motor 110 of the sixth embodiment adjusts the rate of change of the magnetizing dq-axis current command value according to the estimated d-axis inductance Ld and q-axis inductance Lq. As a result, even if the followability of the actual current with respect to the magnetizing dq-axis current command value changes according to the change in inductance, the rate of change of the magnetizing dq-axis current command value can be adjusted according to the change in inductance. Is possible. As a result, the followability of the actual current can be further improved, so that the stability of the current control can be further improved as compared with adjusting only the magnetizing PI control gain.

The present invention is not limited to one embodiment described above. For example, the adjustment of the magnetic PI control gain according to the estimated dq-axis inductance and the adjustment of the time change rate of the magnetizing d-axis current command value Idm ^* and the magnetizing q-axis current command value Iqm ^* are all performed. It is not always necessary to execute it, and it can be omitted. The configurations described in each embodiment may be appropriately combined as long as there is no contradiction.

101 ... q-axis PI controller (q-axis PI controller)
102 ... d-axis PI controller (d-axis PI controller)
103 ... Lq estimation unit (q-axis inductance estimator)
104 ... Ld estimation unit (d-axis inductance estimator)
106 ... d-axis PI control gain adjuster (d-axis gain adjuster)
108 ... Rotation speed acquisition unit (rotation speed estimator)
109 ... Inverter

Claims (18)

Stator with stator windings and
With a rotor with multiple permanent magnets,
In the current control method of a variable magnetic flux motor in which the magnetizing rate of the permanent magnet can be changed by the action of a magnetic field formed by a current applied from an inverter to the stator winding.
The q-axis voltage command value given to the inverter is calculated based on the q-axis current command value for generating the current supplied to the stator winding to the inverter and the q-axis PI control gain.
The d-axis voltage command value to be given to the inverter is calculated based on the d-axis current command value for generating the current supplied to the stator winding to the inverter and the d-axis PI control gain.
The q-axis inductance is estimated based on the q-axis current command value.
Obtaining the rotation speed of the variable magnetic flux motor,
The d-axis current command value, the q-axis current command value, the d-axis voltage command value, the rotation speed, the estimated q-axis inductance, and the previously estimated value of the d-axis inductance. Estimate the shaft inductance and
The d-axis PI control gain is adjusted according to the estimated d-axis inductance.
The q-axis current and the d-axis current corresponding to the q-axis voltage command value and the d-axis voltage command value are supplied from the inverter to the stator winding .
Based on the magnetizing rate command value, the magnetizing d-axis current command value and the magnetizing q-axis current command value for changing the magnetizing rate of the permanent magnet are calculated.
The magnetizing PI control gain is calculated according to the magnetizing d-axis current command value and the magnetizing q-axis current command value.
When changing the magnetizing rate of the permanent magnet, the current control using the d-axis PI control gain and the q-axis PI control gain is switched to the current control using the magnetizing PI control gain.
A current control method for a variable magnetic flux motor. In the current control method for a variable magnetic flux motor according to claim 1,
The q-axis inductance is estimated from the q-axis current command value and the d-axis current command value using a map in which the relationship between the d-axis current and the q-axis current and the q-axis inductance is stored in advance. ,
A current control method for a variable magnetic flux motor. In the current control method for a variable magnetic flux motor according to claim 1,
The q-axis inductance is estimated from the q-axis current command value using a predetermined interpolation formula that interpolates between the maximum value and the minimum value of the q-axis inductance.
A current control method for a variable magnetic flux motor. In the current control method for a variable magnetic flux motor according to claim 3,
The interpolation is linear interpolation,
A current control method for a variable magnetic flux motor. In the current control method for a variable magnetic flux motor according to claim 3,
The interpolation is a non-linear interpolation,
A current control method for a variable magnetic flux motor. In the current control method for a variable magnetic flux motor according to any one of claims 1 to 5,
A predetermined fixed value is used as the initial value of the d-axis inductance.
A current control method for a variable magnetic flux motor. In the current control method for a variable magnetic flux motor according to claim 6,
When executing the initialization sequence for initializing the estimated d-axis inductance, the estimated d-axis inductance value is set to the fixed value.
A current control method for a variable magnetic flux motor. In the current control method for a variable magnetic flux motor according to claim 6,
The induced voltage generated in the stator winding is measured or calculated, and
When executing the initialization sequence for initializing the estimated d-axis inductance, the d-axis inductance calculated value calculated based on the magnet magnetic flux obtained from the induced voltage is set as the initial value.
A current control method for a variable magnetic flux motor. In the current control method for a variable magnetic flux motor according to claim 8,
The initialization sequence is executed when the variable magnetic flux motor operates in an operating range in which the rate of change of the magnetic flux of the magnet with respect to the q-axis current is substantially 0.
A current control method for a variable magnetic flux motor. In the current control method for a variable magnetic flux motor according to claim 9,
In the initialization sequence,
When the q-axis current is substantially 0, the first d-axis magnetic flux calculated by passing the first d-axis current through the stator winding and the second d-axis current are passed through the stator winding. The d-axis inductance calculated value calculated based on the second d-axis magnetic flux calculated by flowing the current into the d-axis is set as the initial value.
A current control method for a variable magnetic flux motor. In the current control method for a variable magnetic flux motor according to claim 9,
In the initialization sequence,
When the q-axis current is substantially the maximum value, the first d-axis magnetic flux calculated by passing the first d-axis current through the stator winding and the second d-axis current are passed through the stator winding. The d-axis inductance calculated value calculated based on the second d-axis magnetic flux calculated by flowing in a line is set as the initial value.
A current control method for a variable magnetic flux motor. In the current control method for a variable magnetic flux motor according to any one of claims 1 to 11.
When the estimated d-axis inductance is equal to or greater than the predetermined d-axis inductance upper limit value, the d-axis inductance is set to the d-axis inductance upper limit value.
When the estimated d-axis inductance is equal to or less than the predetermined d-axis inductance lower limit value, the d-axis inductance is set to the d-axis inductance lower limit value.
A current control method for a variable magnetic flux motor. In the current control method for a variable magnetic flux motor according to claim 12,
When the estimated d-axis PI control gain is equal to or greater than a predetermined gain maximum value at which the current control does not diverge even when the d-axis inductance is the d-axis inductance lower limit value, the d-axis PI control gain. To the maximum gain value,
A current control method for a variable magnetic flux motor. In the current control method for a variable magnetic flux motor according to claim 12,
When the estimated d-axis inductance is equal to or higher than the d-axis inductance upper limit value or the estimated d-axis inductance is equal to or lower than the d-axis inductance lower limit value, the rate of change of the magnet magnetic flux with respect to the q-axis current is first observed. When becomes approximately 0, an initialization sequence for initializing the estimated d-axis inductance is executed.
A current control method for a variable magnetic flux motor. In the current control method for a variable magnetic flux motor according to claim 1 ,
The magnetizing rate of the permanent magnet is estimated and
The magnetizing PI control gain is adjusted according to the magnetizing rate command value and the estimated magnetizing rate.
A current control method for a variable magnetic flux motor. In the current control method for a variable magnetic flux motor according to claim 15 ,
The magnetizing PI control gain is further adjusted according to the estimated d-axis inductance and the q-axis inductance.
A current control method for a variable magnetic flux motor. The method for controlling a current of a variable magnetic flux motor according to any one of claims 1 to 16 .
The rate of change of the magnetizing d-axis current command value and the magnetizing q-axis current command value is adjusted according to the estimated d-axis inductance and the q-axis inductance.
A current control method for a variable magnetic flux motor. Stator with stator windings and
With a rotor with multiple permanent magnets,
In the current control device of a variable magnetic flux motor in which the amount of magnetization of the permanent magnet can be changed by the action of a magnetic field formed by a current applied from an inverter to the stator winding.
Q-axis PI control that calculates the q-axis voltage command value given to the inverter based on the q-axis current command value for generating the current supplied to the stator winding to the inverter and the q-axis PI control gain. Department and
D-axis PI control that calculates the d-axis voltage command value given to the inverter based on the d-axis current command value for generating the current supplied to the stator winding to the inverter and the d-axis PI control gain. Department and
An Lq estimation unit that estimates the q-axis inductance based on the q-axis current command value,
A rotation speed acquisition unit that acquires the rotation speed of the variable magnetic flux motor,
The d-axis current command value, the q-axis current command value, the d-axis voltage command value, the rotation speed, the estimated q-axis inductance, and the previously estimated value of the d-axis inductance. Ld estimation unit that estimates shaft inductance and
A d-axis PI control gain adjusting unit that adjusts the d-axis PI control gain according to the estimated d-axis inductance, and a d-axis PI control gain adjusting unit .
The magnetizing d-axis current command value and the magnetizing q-axis current command value for changing the magnetizing rate of the permanent magnet are calculated based on the magnetizing rate command value, and the magnetizing d-axis current command value and the magnetizing A magnetizing PI control unit that calculates the magnetizing PI control gain according to the magnetic q-axis current command value,
With
The q-axis current and the d-axis current corresponding to the q-axis voltage command value and the d-axis voltage command value are supplied from the inverter to the stator winding .
When changing the magnetizing rate of the permanent magnet, the current control using the d-axis PI control gain and the q-axis PI control gain is switched to the current control using the magnetizing PI control gain.
A motor current control device characterized by this.