JP5807524B2 - Control device for voltage converter - Google Patents

Description

  The present invention relates to a technical field of a control device for a voltage conversion device mounted on, for example, a vehicle.

  2. Description of the Related Art In recent years, as an environmentally-friendly vehicle, an electric vehicle that is mounted with a power storage device (for example, a secondary battery or a capacitor) and travels using a driving force generated from electric power stored in the power storage device has attracted attention. Examples of the electric vehicle include an electric vehicle, a hybrid vehicle, and a fuel cell vehicle.

  In these electric vehicles, a motor generator for generating driving force for traveling by receiving electric power from the power storage device when starting or accelerating, and generating electric power by regenerative braking during braking to store electric energy in the power storage device May be provided. Thus, in order to control a motor generator according to a driving | running | working state, an inverter is mounted in an electric vehicle.

  In such a vehicle, a voltage conversion device (converter) may be provided between the power storage device and the inverter in order to stably supply power used by the inverter that varies depending on the vehicle state. With this converter, the inverter input voltage can be made higher than the output voltage of the power storage device to increase the output of the motor and reduce the motor current at the same output, thereby reducing the size and cost of the inverter and motor. Can be achieved.

  In the configuration including the converter described above, for example, a current sensor that detects a current value of power input from the power storage device or the like is provided in order to control the operation of the device. In such a current sensor, for example, a value is detected based on a reference offset value (that is, the origin). However, if a deviation occurs in the origin, it is difficult to detect an accurate value. For this reason, for example, Patent Document 1 proposes a technique of performing offset correction of the current sensor in a state where the current is interrupted.

JP 2006-246564 A

  However, in the technique described in Patent Document 1 described above, offset correction can be performed only in a state where the current is completely cut off. Therefore, offset correction cannot be performed during the operation of the converter. Therefore, for example, when the driving state continues for a long time as in an automobile application, the opportunity to perform the offset correction is limited to immediately after activation, and the offset correction cannot be performed periodically. For this reason, if a deviation of the origin occurs due to, for example, a change in temperature characteristics during operation, an incorrect value may continue to be detected until the operation ends.

  As described above, the technique described in Patent Document 1 described above has a technical problem in that the accuracy of the detection value may be significantly reduced because the opportunity for offset correction of the current sensor is limited. Have.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a control device for a voltage conversion device capable of accurately detecting the current value of the current supplied to the voltage conversion device. .

  In order to solve the above-described problem, a control device for a voltage converter according to the present invention is supplied to a first switching element and a second switching element that are connected in series with each other, and to the first switching element and the second switching element. A control device for a voltage conversion device including current detection means for detecting a current value of a current, wherein the duty command signal generation means generates a duty command signal corresponding to a duty ratio of the first switching element and the second switching element. A carrier signal generating means for generating a carrier signal corresponding to a switching frequency of the first switching element and the second switching element, and comparing the duty command signal and the carrier signal with each other, And on / off of each of the second switching elements. Switching control signal generation means for generating a switching control signal for switching each of the switching control signal generation means, and the switching control signal generation means to selectively turn on the first switching element and the second switching element, One-arm drive control means for realizing one-arm drive by only one of the first arm including the first switching element and the second arm including the second switching element, and the one-arm by the first arm A duty command signal generating means for generating a duty command signal for turning off the first switching element and the second switching element for a predetermined period when the driving and the one-arm driving by the second arm are switched to each other; Duty control means for controlling, and the current detection means within the predetermined period And a starting learned means to train as an offset origin detected current value.

  The voltage converter according to the present invention is a converter mounted on a vehicle, for example, and includes a first switching element and a second switching element connected in series with each other. As the first switching element and the second switching element, for example, an IGBT (Insulated Gate Bipolar Transistor), a power MOS (Metal Oxide Semiconductor) transistor, or a power bipolar transistor can be used.

  For example, a diode is connected in parallel to each of the first switching element and the second switching element to form a first arm and a second arm, respectively. In other words, the first switching element forms a first arm, and the switching operation of the first arm can be switched on and off. Similarly, the second switching element forms a second arm, and on / off of driving in the second arm can be switched by the switching operation.

  The voltage conversion device according to the present invention further includes a current detection means for detecting a current value of a current supplied to the first switching element and the second switching element. The current detection means is provided, for example, in a front stage portion of the reactor arranged in a path for supplying current to the first switching element and the second switching element. The current detection means detects a current value based on a difference between a preset offset origin and the detected value.

  A control device for a voltage conversion device according to the present invention is a device that controls the operation of the voltage conversion device described above. For example, one or a plurality of CPUs (Central Processing Units), MPUs (Micro Processing Units), various processors, Various controllers, or various types such as a single or a plurality of ECUs (Electronic Controlled Units), which may appropriately include various storage means such as ROM (Read Only Memory), RAM (Random Access Memory), buffer memory or flash memory. It can take the form of various computer systems such as processing units, various controllers or microcomputer devices.

  During the operation of the control device of the voltage converter according to the present invention, the duty command signal generation means generates a duty command signal corresponding to the duty ratio of the first switching element and the second switching element. The duty command signal is determined based on, for example, a voltage value or a current value to be output.

  Further, when the control device of the voltage converter according to the present invention operates, a carrier signal corresponding to the switching frequency of the first switching element and the second switching element is generated by the carrier signal generation means. The carrier signal is generated as a signal having a preset frequency.

  The duty command signal and the carrier signal are compared with each other by the switching control signal generation means, and as a result, a switching control signal for switching on / off of each of the first switching element and the second switching element is generated. The switching control signal is supplied to the first switching element and the second switching element. Thereby, the drive of the 1st arm and the 2nd arm of a voltage converter is controlled.

  The switching control signal generation means described above may be controlled by the one-arm drive control means so as to selectively turn on the first switching element and the second switching element. According to such control, one-arm driving by only one of the first arm including the first switching element and the second arm including the second switching element is realized.

  When the one-arm drive control means selects the first arm and the second switching element including the first switching element, the first arm and the second arm are selected based on, for example, a voltage value or a current value to be output. It is determined which one of the arms should be driven with one arm. More specifically, for example, when the motor generator connected to the voltage converter performs a regenerative operation, the single arm drive control means performs the one-arm drive by the first arm and performs the power running operation. One arm drive by the second arm is performed. Thus, the one-arm drive control means performs control so that the one-arm drive by the first arm and the one-arm drive by the first arm are appropriately switched.

  Here, in the present invention, in particular, when the one-arm driving by the first arm and the one-arm driving by the second arm are switched to each other, the duty that turns off both the first switching element and the second switching element by the duty control means. The duty command signal generation means is controlled so as to generate a command signal (for example, a signal having a duty ratio of 100% or 0%) for a predetermined period. Here, the “predetermined period” means that the current value of the current detected by the current detection means becomes sufficiently low (preferably zero) in the origin learning of the current detection means described later. This is a required period, and is determined and set in advance theoretically, experimentally or empirically.

  Further, in the present invention, the current value detected by the current detection means by the origin learning means is used as the offset origin within a predetermined period in which the duty command signal that turns off both the first switching element and the second switching element is generated. To learn. That is, the origin learning means performs correction so as to replace the offset origin stored so far with a value obtained within a predetermined period.

  As described above, when the first switching element and the second switching element are both controlled to be turned off, the value detected by the current detection means is attenuated toward zero during that period. Therefore, if the value detected within the predetermined period (preferably immediately before the end of the predetermined period) is used as the offset origin, the accuracy of the current value detected by the current detecting means can be improved. More specifically, for example, the offset origin value that has changed due to a change in temperature characteristics or the like can be updated to an accurate value each time the arm is switched.

  Note that origin learning does not always have to be performed each time the arm is switched, and there is a possibility that the offset origin may change (for example, when a predetermined time has elapsed since the previous learning, or when the environmental temperature has changed by a predetermined value since the previous learning) If it is done).

  In addition, when the arm is switched, by providing a predetermined period during which both the first switching element and the second switching element are turned off, one of the first switching element and the second switching element is turned off, and the other is turned on. It is preferable to prevent a short circuit between the first switching element and the second switching element due to a shorter period until the switch is turned on (that is, the switching timings of the first switching element and the second switching element are close to each other). can do.

  As described above, according to the control device for a voltage converter according to the present invention, the two switching elements in the voltage converter are prevented from being short-circuited, and the current value of the current supplied to the voltage converter is accurately detected. Is possible.

  The effect | action and other gain of this invention are clarified from the form for implementing invention demonstrated below.

It is the schematic which shows the whole structure of the vehicle by which the control apparatus of the voltage converter which concerns on embodiment is mounted. It is a block diagram which shows the structure of ECU which concerns on embodiment. It is a flowchart which shows the whole operation | movement of the control apparatus of the voltage converter which concerns on embodiment. It is a flowchart which shows the origin learning operation | movement of the control apparatus of the voltage converter which concerns on embodiment. It is a timing chart which shows the change of various parameters at the time of origin learning of the control device of the voltage converter concerning an embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, an overall configuration of a vehicle in which a control device for a voltage converter according to the present embodiment is mounted will be described with reference to FIG. FIG. 1 is a schematic diagram showing the overall configuration of a vehicle in which the control device for a voltage conversion device according to this embodiment is mounted.

  In FIG. 1, a vehicle 100 on which a control device for a voltage converter according to this embodiment is mounted is configured as a hybrid vehicle using an engine 40 and motor generators MG1 and MG2 as power sources. However, the configuration of the vehicle 100 is not limited to this, and the vehicle 100 can be applied to a vehicle (for example, an electric vehicle or a fuel cell vehicle) that can be driven by electric power from the power storage device. Moreover, although this embodiment demonstrates the structure mounted in the vehicle 100 by the control apparatus of a voltage converter, it is applicable if it is an apparatus driven by an AC motor other than a vehicle.

  The vehicle 100 includes a DC voltage generator 20, a load device 45, a smoothing capacitor C2, and an ECU 30.

  DC voltage generation unit 20 includes a power storage device 28, system relays SR1 and SR2, a smoothing capacitor C1, and a converter 12.

  The power storage device 28 includes a secondary battery such as nickel hydride or lithium ion, and a power storage device such as an electric double layer capacitor. Further, the DC voltage VB output from the power storage device 28 and the input / output DC current IB are detected by the voltage sensor 10 and the current sensor 11, respectively. Then, the voltage sensor 10 and the current sensor 11 output detected values of the detected DC voltage VB and DC current IB to the ECU 30.

  System relay SR1 is connected between the positive terminal of power storage device 28 and power line PL1, and system relay SR2 is connected between the negative terminal of power storage device 28 and ground line NL. System relays SR <b> 1 and SR <b> 2 are controlled by a signal SE from ECU 30, and switch between supply and interruption of power from power storage device 28 to converter 12.

  Converter 12 is an example of the “voltage converter” of the present invention, and includes a reactor L1, switching elements Q1 and Q2, and diodes D1 and D2. The switching elements Q1 and Q2 are examples of the “first switching element” and the “second switching element” of the present invention, and are connected in series between the power line PL2 and the ground line NL. Switching elements Q1 and Q2 are controlled by a switching control signal PWC from ECU 30.

  As the switching elements Q1 and Q2, for example, an IGBT, a power MOS transistor, a power bipolar transistor, or the like can be used. Anti-parallel diodes D1 and D2 are arranged for switching elements Q1 and Q2. Reactor L1 is provided between a connection node of switching elements Q1 and Q2 and power line PL1. Smoothing capacitor C2 is connected between power line PL2 and ground line NL.

  The current sensor 18 is an example of the “current detection means” in the present invention, detects the reactor current flowing through the reactor L1, and outputs the detected value IL to the ECU 30.

  Load device 45 includes an inverter 23, motor generators MG <b> 1 and MG <b> 2, an engine 40, a power split mechanism 41, and drive wheels 42. Inverter 23 includes an inverter 14 for driving motor generator MG1 and an inverter 22 for driving motor generator MG2. As shown in FIG. 1, it is not essential to provide two sets of inverters and motor generators. For example, only one set of inverter 14 and motor generator MG1 or inverter 22 and motor generator MG2 may be provided.

  Motor generators MG1 and MG2 receive AC power supplied from inverter 23 and generate rotational driving force for vehicle propulsion. Motor generators MG1 and MG2 receive rotational force from the outside, generate AC power according to a regenerative torque command from ECU 30, and generate regenerative braking force in vehicle 100.

  Motor generators MG1 and MG2 are also coupled to engine 40 via power split mechanism 41. Then, the driving force generated by engine 40 and the driving force generated by motor generators MG1, MG2 are controlled to have an optimal ratio. Alternatively, either one of motor generators MG1 and MG2 may function exclusively as an electric motor, and the other motor generator may function exclusively as a generator. In the present embodiment, it is assumed that motor generator MG1 functions as a generator driven by engine 40, and motor generator MG2 functions as an electric motor that drives drive wheels 42.

  For the power split mechanism 41, for example, a planetary gear mechanism (planetary gear) is used in order to distribute the power of the engine 40 to both the drive wheels 42 and the motor generator MG1.

  Inverter 14 receives the boosted voltage from converter 12, and drives motor generator MG1 to start engine 40, for example. Inverter 14 also outputs regenerative power generated by motor generator MG <b> 1 by mechanical power transmitted from engine 40 to converter 12. At this time, converter 12 is controlled by ECU 30 to operate as a step-down circuit.

  Inverter 14 is provided in parallel between power line PL2 and ground line NL, and includes U-phase upper and lower arms 15, V-phase upper and lower arms 16, and W-phase upper and lower arms 17. Each phase upper and lower arm is composed of a switching element connected in series between power line PL2 and ground line NL. For example, the U-phase upper and lower arms 15 are composed of switching elements Q3 and Q4, the V-phase upper and lower arms 16 are composed of switching elements Q5 and Q6, and the W-phase upper and lower arms 17 are composed of switching elements Q7 and Q8. Antiparallel diodes D3 to D8 are connected to switching elements Q3 to Q8, respectively. Switching elements Q3 to Q8 are controlled by a switching control signal PWI from ECU 30.

  For example, motor generator MG1 is a three-phase permanent magnet type synchronous motor, and one end of three coils of U, V, and W phases is commonly connected to a neutral point. Further, the other end of each phase coil is connected to a connection node of switching elements of upper and lower arms 15 to 17 for each phase.

  Inverter 22 is connected to converter 12 in parallel with inverter 14.

  Inverter 22 converts the DC voltage output from converter 12 into three-phase AC and outputs the same to motor generator MG2 that drives drive wheels. Inverter 22 also outputs regenerative power generated by motor generator MG2 to converter 12 along with regenerative braking. At this time, converter 12 is controlled by ECU 30 to operate as a step-down circuit. Although the internal configuration of the inverter 22 is not shown, it is the same as that of the inverter 14 and will not be described in detail.

  Converter 12 is basically controlled such that switching elements Q1 and Q2 are turned on and off in a complementary manner in each switching period. During boosting operation, converter 12 boosts DC voltage VB supplied from power storage device 28 to DC voltage VM (this DC voltage corresponding to the input voltage to inverter 14 is also referred to as “system voltage” hereinafter). This boosting operation is performed by supplying the electromagnetic energy accumulated in the reactor L1 during the ON period of the switching element Q2 to the power line PL2 via the switching element Q1 and the antiparallel diode D1.

  Further, converter 12 steps down DC voltage VM to DC voltage VB during the step-down operation. This step-down operation is performed by supplying the electromagnetic energy accumulated in the reactor L1 during the ON period of the switching element Q1 to the ground line NL via the switching element Q2 and the antiparallel diode D2.

  The voltage conversion ratio (ratio between VM and VB) in these step-up and step-down operations is controlled by the on-period ratio (duty ratio) of the switching elements Q1 and Q2 in the switching period. Note that if the switching elements Q1 and Q2 are fixed to ON and OFF, respectively, VM = VB (voltage conversion ratio = 1.0) can be obtained.

  Smoothing capacitor C <b> 2 smoothes the DC voltage from converter 12 and supplies the smoothed DC voltage to inverter 23. The voltage sensor 13 detects the voltage across the smoothing capacitor C2, that is, the system voltage VM, and outputs the detected value to the ECU 30.

  When the torque command value of motor generator MG1 is positive (TR1> 0), inverter 14 responds to switching control signal PWI1 from ECU 30 when a DC voltage is supplied from smoothing capacitor C2, and switching elements Q3-Q8 The motor generator MG1 is driven so as to convert a DC voltage into an AC voltage and output a positive torque by the switching operation. Further, when the torque command value of motor generator MG1 is zero (TR1 = 0), inverter 14 converts the DC voltage into the AC voltage and the torque becomes zero by the switching operation in response to switching control signal PWI1. In this manner, motor generator MG1 is driven. Thus, motor generator MG1 is driven to generate zero or positive torque designated by torque command value TR1.

  Furthermore, during regenerative braking of vehicle 100, torque command value TR1 of motor generator MG1 is set negative (TR1 <0). In this case, inverter 14 converts the AC voltage generated by motor generator MG1 into a DC voltage by a switching operation in response to switching control signal PWI1, and converts the converted DC voltage (system voltage) to smoothing capacitor C2. To the converter 12. The regenerative braking here refers to braking with regenerative power generation when the driver operating the electric vehicle performs a footbrake operation, or regenerative braking by turning off the accelerator pedal while driving, although the footbrake is not operated. This includes decelerating (or stopping acceleration) the vehicle while generating electricity.

  Similarly, inverter 22 receives switching control signal PWI2 from ECU 30 corresponding to the torque command value of motor generator MG2, receives a switching control signal PWI2, and converts the DC voltage into an AC voltage to a predetermined torque by a switching operation. The motor generator MG2 is driven so that

  Current sensors 24 and 25 detect motor currents MCRT1 and MCRT2 flowing through motor generators MG1 and MG2, and output the detected motor currents to ECU 30. Since the sum of the instantaneous values of the currents of the U-phase, V-phase, and W-phase is zero, the current sensors 24 and 25 are arranged to detect the motor current for two phases as shown in FIG. All you need is enough.

  Rotation angle sensors (resolvers) 26 and 27 detect rotation angles θ1 and θ2 of motor generators MG1 and MG2, and send the detected rotation angles θ1 and θ2 to ECU 30. ECU 30 can calculate rotational speeds MRN1, MRN2 and angular speeds ω1, ω2 (rad / s) of motor generators MG1, MG2 based on rotational angles θ1, θ2. Note that the rotation angle sensors 26 and 27 may not be arranged by directly calculating the rotation angles θ1 and θ2 from the motor voltage and current in the ECU 30.

  The ECU 30 is an example of a “voltage conversion device control device” of the present invention, and includes a CPU (Central Processing Unit), a storage device, and an input / output buffer (not shown), and controls each device of the vehicle 100. Note that these controls are not limited to software processing, and can be constructed and processed by dedicated hardware (electronic circuit).

  As representative functions, the ECU 30 includes the input torque command values TR1 and TR2, the DC voltage VB detected by the voltage sensor 10, the DC current IB detected by the current sensor 11, and the system voltage detected by the voltage sensor 13. Based on the motor currents MCRT1 and MCRT2 from the VM and current sensors 24 and 25, the rotation angles θ1 and θ2 from the rotation angle sensors 26 and 27, etc., the motor generators MG1 and MG2 generate torques according to the torque command values TR1 and TR2. The operations of the converter 12 and the inverter 23 are controlled so as to output. That is, switching control signals PWC, PWI1, and PWI2 for controlling converter 12 and inverter 23 as described above are generated and output to converter 12 and inverter 23, respectively.

  During the boosting operation of converter 12, ECU 30 feedback-controls system voltage VM and generates switching control signal PWC so that system voltage VM matches the voltage command value.

  Further, when vehicle 100 enters the regenerative braking mode, ECU 30 generates switching control signals PWI1 and PWI2 so as to convert the AC voltage generated by motor generators MG1 and MG2 into a DC voltage, and outputs it to inverter 23. Thus, inverter 23 converts the AC voltage generated by motor generators MG1 and MG2 into a DC voltage and supplies it to converter 12.

  Further, when vehicle 100 enters the regenerative braking mode, ECU 30 generates a switching control signal PWC so as to step down the DC voltage supplied from inverter 23 and outputs it to converter 12. Thus, the AC voltage generated by motor generators MG1 and MG2 is converted into a DC voltage, and is further stepped down and supplied to power storage device 28.

  Next, a specific configuration of the ECU 30 that is a control device of the voltage conversion device according to the present embodiment will be described with reference to FIG. FIG. 2 is a block diagram showing the configuration of the ECU according to this embodiment.

  2, the ECU 30 according to the present embodiment includes a voltage command generation unit 200, a voltage control unit 210, a duty command switching unit 230, a carrier comparison comparator 250, a sampling hold unit 240, and a carrier signal generation unit 250. , A reference value calculation unit 260, a one-arm drive determination unit 270, a duty command switching determination unit 281, a duty command switching holding unit 282, an origin learning necessity determination unit 285, and an origin value holding unit 290. It is configured.

  Voltage command generation unit 200 receives input of required torques TR1, TR2 to motor generators MG1, MG2 and rotational speeds MRN1, MRN2 of motor generators MG1, MG2. Based on these pieces of information, voltage command generation unit 200 generates voltage command VREF for the output voltage of converter 12 (that is, the input voltage of inverter 14).

  The voltage control unit 210 is an example of the “duty command signal generation unit” of the present invention, and includes a current command generation unit 213 including a subtraction unit 211 and a voltage control calculation unit 212, a subtraction unit 221 and a current control calculation unit 222. And a current control unit 220.

  The subtraction unit 211 in the current command generation unit 213 calculates a voltage deviation between the voltage command VREF received from the voltage command generation unit 200 and the feedback value VM of the system voltage of the converter 12 detected by the voltage sensor 13. The result is output to the voltage control calculation unit 212.

  The voltage control calculation unit 212 calculates the reactor current command value ILREF flowing through the reactor L1 by performing PI calculation on the voltage deviation calculated by the subtraction unit 211.

  Thus, current command generation unit 213 calculates reactor current command value ILREF by performing feedback control of the system voltage of converter 12.

  The voltage control calculation unit 212 outputs the reactor current command value ILREF to the current control unit 220, the one-arm drive determination unit 270, and the duty command switching determination unit 281.

  The subtraction unit 221 in the current control unit 220 has a current deviation between the reactor current command value ILREF from the voltage control calculation unit 212 and the feedback value of the reactor current IL in which the detection value is held for each switching period by the sampling hold unit 240. Is output to the current control calculation unit 222.

  The current control calculation unit 222 calculates the duty of the switching elements Q1, Q2 by performing PI calculation on the current deviation calculated by the subtraction unit 221. It should be noted that the current control calculation unit 222 only selects the switching element on the selected side when the one-arm driving control of the switching element Q1 or Q2 is selected by the selection flag SEL from the one-arm driving determination unit 270 described later. To calculate the duty so that the reactor current command value ILREF is output.

  The duty command switching unit 230 is an example of the “duty control means” of the present invention, and the duty and the duty ratio from the current control calculation unit 222 are set to a predetermined duty and the duty ratio set to 0%. The duty signal DUTY is output to the carrier comparison comparator 235.

  The carrier comparison comparator 235 is an example of the “switching control signal generation unit” of the present invention, and based on a comparison between the duty signal DUTY and the carrier CR from the carrier signal generation unit 250, the upper and lower arms of each phase of the converter 12 The switching control signal PWC for controlling on / off of the switching elements Q1, Q2 is generated. At this time, the carrier comparison comparator 235 selects the switching elements Q1 and Q2 to be driven according to the selection flag SEL from the one-arm drive determination unit 270.

  With this switching control signal PWC, when motor generators MG1, MG2 are in power running, the output voltage from power storage device 28 is boosted to the desired input voltage of inverter 23. When motor generators MG1 and MG2 are regenerative, DC power generated by motor generators MG1 and MG2 and converted by inverter 23 is stepped down to a voltage that power storage device 28 can charge.

  The carrier signal generation unit 250 is an example of the “carrier signal generation unit” in the present invention, and outputs a carrier signal CR having a frequency corresponding to the carrier frequency command to the carrier comparison comparator 235. Further, the carrier signal generation unit 250 outputs the sampling signal SMP to the sampling hold unit 240 for each cycle of the carrier signal CR. The sampling hold unit 240 detects and holds the reactor current IL detected by the current sensor 18 when each sampling signal SMP is input, and outputs the detected current value to the subtraction unit 245.

  The origin value holding unit 290 holds an origin value for detecting an accurate current value by offset, and outputs the origin value to the subtracting unit 245. The subtraction unit 245 performs a subtraction process on the value input from the sampling hold unit 245 using the origin value input from the origin value holding unit 290, and outputs a value obtained as a calculation result to the subtraction unit 221. Note that the origin value held in the origin value holding unit 290 can be rewritten by a learning operation described later.

  Reference value calculation unit 260 receives input of output voltage VB of power storage device 28 and system voltage VM. Then, from these pieces of information, a current reference value IL1 at which the direction of the reactor current IL is switched from positive to negative or from negative to positive during one cycle of the carrier wave CR is calculated, and the one-arm drive determining unit 270 is calculated. Output.

  Single arm drive determination unit 270 receives input of reactor current command value ILREF from voltage control calculation unit 212 and current reference value IL1 from reference value calculation unit 260. The single arm drive determination unit 270 selects a switching element to be driven based on these pieces of information. Then, the one-arm drive determination unit 270 outputs a selection flag SEL that is a selection result to the carrier comparison comparator 235.

  Duty command switching determination unit 281 receives reactor current command value ILREF from voltage control calculation unit 212 as an input, and determines to which switch the duty command switching unit 230 is switched. That is, the duty command switching unit 230 outputs the duty from the current control calculation unit 222, a predetermined duty with a duty ratio of 100%, and a predetermined duty with a duty ratio of 0% as the duty signal DUTY. Determine whether. The determination result in the duty command switching unit 230 is output to the duty command switching holding unit 282.

  The origin learning necessity determination unit 285 determines that the origin learning should be performed when it is estimated that the origin value held in the origin holding unit 290 is not accurate. The origin learning necessity determination unit 285 determines that the origin learning should be performed when, for example, a predetermined time has elapsed since the previous learning or when the environmental temperature changes by a predetermined value or more. The determination result in the origin learning necessity determination unit 285 is output to the duty command switching holding unit 282.

  The duty command switching holding unit 282 receives the determination result in the duty command switching unit 230 and the determination result in the origin learning necessity determination unit 285 as inputs, and based on these determination results, the switch switching control in the duty command switching unit 230 is performed. And the learning of the origin value in the origin value holding unit 290 is executed. That is, the duty command switching holding unit 282 here is an example of the “origin learning unit” in the present invention. The detailed operation of the duty command switching holding unit 282 will be described in detail later.

  ECU30 comprised including each part mentioned above is an electronic control unit comprised integrally, and it is comprised so that all the operation | movement concerning each said part may be performed by ECU30. However, the physical, mechanical, and electrical configurations of the above-described parts according to the present invention are not limited thereto. For example, each of these parts includes various ECUs, various processing units, various controllers, microcomputer devices, and the like. It may be configured as a computer system or the like.

  Next, operation | movement of the control apparatus of the voltage converter which concerns on this embodiment is demonstrated with reference to FIG. FIG. 3 is a flowchart showing the overall operation of the control device of the voltage converter according to this embodiment. Note that each step in the flowchart shown in FIG. 3 excludes the process at the time of duty command switching and the process at the time of learning the origin for convenience of explanation. These excluded processes will be described later with reference to FIG. 4, and the overall process flow of the apparatus will be described here.

  In FIG. 3, when the control device of the voltage converter according to the present embodiment operates, the ECU 30 calculates the voltage command VREF by the voltage command generator 200 (step S101).

  Subsequently, the ECU 30 calculates the reactor current command value ILREF by the voltage control calculation unit 212 (step S102).

  Next, ECU 30 determines whether or not reactor current command ILREF is positive, that is, whether or not motor generators MG1 and MG2 are controlled in a power running state (step S103).

  Here, when reactor current command ILREF is positive (step S103: YES), ECU 30 sets by single arm drive determination unit 270 to perform single arm drive control of switching element Q2, which is the lower arm (step S104). ).

  On the other hand, when reactor current command ILREF is zero or negative (step S103: NO), motor generators MG1 and MG2 are controlled in a regenerative state, and thus ECU 30 performs one-arm drive control of switching element Q1, which is the upper arm. (Step S105). When reactor current command ILREF is zero, voltage conversion by converter 12 is not performed, so neither the upper and lower arms are actually driven.

  Next, the ECU 30 calculates the duty of the switching elements Q1, Q2 by the current control calculation unit 222 based on the drive arm set in step S104 or step S105 and the reactor current command value ILREF (step S106).

  ECU 30 generates switching control signals PWC1 and PWC2 for driving switching elements Q1 and Q2 of converter 12 by carrier comparison comparator 235 based on the comparison between duty DUTY of switching elements Q1 and Q2 and carrier signal CR. Output to the converter 12.

By controlling converter 12 according to switching control signal PWC generated by the above processing, when motor generators MG1 and MG2 are in power running, only lower arm (switching element Q2) is driven, and motor generators MG1 and MG1 are driven. When MG2 is regenerative, control is executed so that only the upper arm (switching element Q1) is driven.
Next, the operation at the time of origin learning by the control device of the voltage converter according to the present embodiment will be described with reference to FIG. FIG. 4 is a flowchart showing the origin learning operation of the control device of the voltage converter according to the embodiment.

  In FIG. 4, when the control device of the voltage converter according to the present embodiment operates, first, the origin learning necessity determination unit 285 determines whether or not origin learning should be performed (step S201). Here, “origin learning” refers to a process of correcting the origin value held in the origin value holding unit 290 in order to make the IL value detected by the current sensor 18 more accurate. Pointing.

  When it is determined that the origin learning should be performed (step S201: YES), the duty command switching determination unit 281 determines whether or not the lower arm is selected in the one-arm drive determination unit 270 (that is, the switching element Q2 is turned on). It is determined whether or not it is selected (step S202).

  When the one-arm drive determining unit 270 determines that the lower arm is selected (step S202: YES), the duty command switching holding unit 282 sets the switch switching control holding time in the duty command switching unit 230 to “T1”. At the same time, the origin learning flag is set to “necessary” (step S203). On the other hand, when the one-arm drive determining unit 270 determines that the lower arm is not selected (in other words, the upper arm is selected) (step S202: NO), the duty command switching holding unit 282 determines the duty command. The switch switching control holding time in the switching unit 230 is set to “T2”, and the origin learning flag is set to “necessary” (step S204). The holding times “T1” and “T2” here are set in advance as the time required for the current value detected by the current sensor 18 to decay to zero.

  On the other hand, when the origin learning necessity determination unit 285 determines that the origin learning should not be performed (step S201: NO), the duty command switching holding unit 282 holds the switch switching control holding time in the duty command switching unit 230. Is set to “T0”, and the origin learning flag is set to “unnecessary” (step S205). Unlike the above-described holding times “T1” and “T2”, the holding time “T0” is set as a time for preventing a short circuit between the upper and lower arms, and typically T1, T2 >> The relationship is T0.

  When the holding time and the origin learning flag are set in steps S203 to S205, duty command switching determination unit 281 determines whether motor generators MG1 and MG2 are switched from the power running state to the regenerative state (step S206). . When duty command switching determination unit 281 determines that motor generators MG1 and MG2 cannot be switched from the power running state to the regenerative state (step S206: NO), motor generators MG1 and MG2 switch from the regenerative state to the power running state. It is determined whether or not (step S207).

  The duty command switching holding unit 282 switches the switch of the duty command switching unit 230 based on the determination results of steps S206 and S207 described above. Specifically, when motor generators MG1 and MG2 are switched from the power running state to the regenerative state (step S206: YES), duty signal is set to 0% and duty signal DUTY is output (step S208). When motor generators MG1 and MG2 are switched from the regenerative state to the power running state (step S207: YES), duty signal is set to 100% and duty signal DUTY is output (step S209). Further, when motor generators MG1 and MG2 do not switch the operation state (step S207: NO), the duty command from current control calculation unit 222 is output as duty signal DUTY (step S210).

  When the duty command from the current control calculation unit 222 is output as the duty signal DUTY (that is, when the motor generators MG1 and MG2 do not switch the operating state), a series of processing is performed without performing the learning operation described later. Ends.

  On the other hand, when the duty command is set to 0% and the duty signal DUTY is output, the duty command switching holding unit 282 determines whether or not the holding time “T1” or “T2” has elapsed since the start of output (step S2). S211). Similarly, when the duty command is set to 100% and the duty signal DUTY is output, the duty command switching holding unit 282 determines whether or not the holding time “T1” or “T2” has elapsed since the output was started. (Step S212).

  When the holding time “T1” or “T2” elapses after the duty signal DUTY is switched (steps S211, S212: YES), the duty command switching holding unit 282 determines whether or not the origin learning flag is set to “necessary”. Determination is made (step S213). Here, when the origin learning flag is “unnecessary” (step S213: NO), the origin learning operation is omitted and a series of processing ends. On the other hand, when the origin learning flag is “necessary” (step S213: YES), the duty command switching holding unit 282 instructs the origin value holding unit 290 to perform origin learning (step S214). ).

  The origin value holding unit 290 instructed to perform origin learning newly holds the value detected at that time as the origin value (that is, rewrites the origin value). Here, in particular, the value that becomes the new origin value is the holding time “T1” or “T2 in a state where the duty command is 0% or 100% (that is, the state where both of the switching elements Q1 and Q2 are turned off). Since it is a value detected when "" has elapsed, it is considered to be a value very close to zero. Therefore, if the origin value is corrected in this way, the current value can be accurately detected even when the origin value is shifted during operation due to, for example, a change in temperature characteristics.

  Even when the origin learning is not performed, when the arm is switched, the switching elements Q1 and Q2 are both temporarily turned off, so that one of the switching elements Q1 and Q2 is turned off. Further, it is possible to suitably prevent short-circuiting of the switching elements Q1 and Q2 due to a shorter period until the other is turned on (that is, the on / off switching timings of the switching elements Q1 and Q2 are close to each other).

  Next, the operation during the above-described origin learning will be described more specifically with reference to FIG. FIG. 5 is a timing chart showing changes in various parameters during the origin learning of the control device of the voltage converter according to the embodiment.

  In FIG. 5, a case where motor generators MG1 and MG2 are switched from the power running state to the regenerative state will be taken as an example. As shown in the figure, it is assumed that the origin learning flag at the start of the chart is “necessary”, and the origination control execution timing is the peak and valley of the carrier signal CR.

  In this case, at the timing when motor generators MG1, MG2 are switched from the power running state to the regenerative state, first, the duty command is switched to 0%. When the duty command is 0%, the holding time “T1” is held as described above.

  When the duty command is switched to 0%, both the switching elements Q1, Q2 are turned off, and the output value of the current sensor 18 attenuates toward zero. In addition, the value of di / dt which is the deceleration speed at this time is expressed by the following formulas (1) and (2) using the output voltage VB of the power storage device 28, the system voltage VM, and the reactor value L of the reactor L1. Can be represented.

When lower arm is selected: di / dt = (VB−VM) / L (1)
When upper arm is selected: di / dt = VB / L (2)
Therefore, if the holding times “T1” and “T2” are set based on di / dt expressed by the above formula and the estimated value of IL at that time, the time until the current value decays to zero can be obtained. Accurate estimation can be performed, and origin learning can be performed more preferably. Note that it is preferable to estimate the estimated value of IL to be large in order to surely attenuate the current value to zero. However, inconvenience may occur even if the value is too large. For example, a value obtained by adding the worst error amount to the maximum rated current of the converter 12 or the output value of the current sensor 18 before correction may be used.

  When the holding time T1 elapses, offset correction (origin learning) is performed assuming that the output value of the current sensor 18 at that time is zero. Thereby, even if the output value of the current sensor 18 before correction includes an offset error, the output value of the current sensor 18 after correction becomes a true IL value.

  After the offset correction is performed, the duty command is returned to the original value from the current control calculation unit 222 to start driving the upper arm. Here, as can be seen from the figure, at least the holding time “T1” is released from when the lower arm is turned off to when the upper arm is turned on, so that the switching elements Q1 and Q2 are short-circuited. It can be surely prevented.

  As described above, according to the control device of the voltage converter according to the present embodiment, the two switching elements in the converter 12 are prevented from being short-circuited, and the current value of the current supplied to the converter 12 is accurately detected. It is possible.

  The present invention is not limited to the above-described embodiments, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification. These control devices are also included in the technical scope of the present invention.

  DESCRIPTION OF SYMBOLS 12 ... Converter, 18 ... Current sensor, 20 ... DC voltage generation part, 22, 23 ... Inverter, 28 ... Power storage device, 30 ... ECU, 40 ... Engine, 41 ... Power split mechanism, 42 ... Drive wheel, 45 ... Load device , 100 ... vehicle, 200 ... voltage command generation unit, 210 ... voltage control unit, 211 ... subtraction unit, 212 ... voltage control calculation unit, 213 ... current command generation unit, 220 ... current control unit, 221 ... subtraction unit, 222 ... Current control calculation unit, 230 ... duty command switching unit, 235 ... carrier comparison comparator, 240 ... sampling hold unit, 245 ... subtraction unit, 250 ... carrier signal generation unit, 260 ... reference value calculation unit, 270 ... one arm drive determination unit , 281 ... Duty command switching determination unit, 282 ... Duty command switching holding unit, 285 ... Origin learning necessity determination unit, 290 ... Origin value holding unit C2 ... smoothing capacitor, D1, D2 ... diodes, L1 ... reactor, MG1, MG2 ... motor-generator, Q1, Q2 ... switching device, SR1, SR2 ... system relay.

Claims (1)

A control device for a voltage converter, comprising: a first switching element and a second switching element connected in series to each other; and a current detection means for detecting a current value of a current supplied to the first switching element and the second switching element. Because
Duty command signal generating means for generating a duty command signal corresponding to a duty ratio of the first switching element and the second switching element;
Carrier signal generating means for generating a carrier signal corresponding to a switching frequency of the first switching element and the second switching element;
Switching control signal generating means for respectively generating a switching control signal for switching on and off of each of the first switching element and the second switching element by comparing the duty command signal and the carrier signal;
The first arm including the first switching element and the second switching are controlled by controlling the switching control signal generation unit so as to selectively turn on the first switching element and the second switching element. One-arm drive control means for realizing one-arm drive by only one of the second arms including the element;
When the one-arm driving by the first arm and the one-arm driving by the second arm are switched to each other, a duty command signal for turning off both the first switching element and the second switching element is generated for a predetermined period. Duty control means for controlling the duty command signal generating means;
A control device for a voltage converter, comprising: origin learning means for learning the current value detected by the current detection means within the predetermined period as an offset origin.

Images