JP5495029B2 - Control device for motor drive device - Google Patents

Description

  The present invention includes a voltage conversion unit that converts a power supply voltage from a DC power source to generate a desired system voltage, a DC / AC conversion unit that converts DC power having the system voltage into AC power and supplies the AC power to an AC motor; The present invention relates to a control device that controls an electric motor drive device including

  As an electric motor drive device for driving an AC motor, a DC / AC converter such as an inverter that converts DC power from a DC power source into AC power and supplies the AC motor, and a DC voltage supplied to the DC / AC converter are boosted. A configuration including a voltage conversion unit such as a converter is already known. In such a motor drive device, PWM (pulse width modulation) control and maximum torque control based on vector control are performed in order to efficiently generate torque by supplying a sinusoidal AC voltage to the coils of each phase of the AC motor. A lot has been done. By the way, the induced voltage of the electric motor increases as the rotational speed increases, and the AC voltage (hereinafter referred to as “required voltage”) required to drive the electric motor also increases. When this required voltage exceeds the maximum AC voltage that can be output from the DC / AC converter (hereinafter referred to as “maximum output voltage”), it becomes impossible to pass the necessary current to the coil, and the motor is controlled appropriately. Can not do it. Therefore, the maximum output voltage that can be output from the DC / AC converter is increased by boosting the DC voltage by the voltage converter and supplying it to the DC / AC converter. In order to reduce the induced voltage generated by the motor, field weakening control is also performed to adjust the current command value supplied to the motor so as to weaken the field magnetic flux of the motor. Further, as the induced voltage generated by the electric motor becomes higher, the control of the voltage waveform output from the DC / AC converter is shifted from sine wave PWM control to overmodulation PWM control, and further to rectangular wave control.

  The following Patent Document 1 describes a technology of a control device that determines a value of a DC voltage boosted by a voltage converter and supplied to a DC / AC converter based on a map of target torque and rotational speed of the AC motor. ing. The control device sets the gradient of the DC voltage that increases with the increase in the rotational speed of the AC motor in the map so that the gradient of the DC voltage becomes gentler after the start of field weakening control than that before the start of field weakening control. The region where the wave control is performed can be expanded.

JP 2009-136141 A

  By the way, when field-weakening control is performed, since the current flowing through the coil increases to generate the same torque in the motor, the copper loss increases, while the magnetic flux of the permanent magnet of the AC motor is substantially decreased. Iron loss generated in the core is reduced. Accordingly, by appropriately controlling the field weakening current amount in the field weakening control according to the ratio of the copper loss and the iron loss that changes depending on the operation state of the motor, the efficiency of the entire system including the motor and the motor driving device is improved. It is possible. However, with the technique of the above-mentioned Patent Document 1, the field-weakening current amount is not always an appropriate value.

  Therefore, the field adjustment value for adjusting the direction in which the field magnetic flux is weakened with respect to the command value of the current supplied from the DC / AC converter to the AC motor is an appropriate value according to the operating state of the AC motor. It is desired to realize a control device for an electric motor drive device that can be controlled.

  According to the present invention, a voltage converter that converts a power supply voltage from a DC power supply to generate a desired system voltage, and a DC that converts DC power supplied from the voltage converter into AC power and supplies the AC power to an AC motor The characteristic configuration of the control device that controls the motor driving device including the AC conversion unit is a command value of a current supplied from the DC / AC conversion unit to the AC motor based on a target torque of the AC motor. A current command determination unit for determining a current command value; and the AC motor with respect to the current command value such that the current command value falls within a possible output range determined based on the system voltage and the rotational speed of the AC motor. A field adjustment unit that determines a field adjustment command value that is a command value of a field adjustment value that performs adjustment in a direction to weaken the field magnetic flux, and a current supplied from the DC / AC conversion unit to the AC motor The actual field adjustment value that is the actual field adjustment value detected based on the current command value, or the target field adjustment value acquisition unit that acquires the field adjustment command value as the target field adjustment value. A target field adjustment value determining unit that determines a target field adjustment value that is a control target value of the target field adjustment value based on a target torque of the AC motor and a rotation speed of the AC motor; and the target A system voltage determination unit that determines a system voltage command value that is a command value of the system voltage so that a field adjustment value matches the target field adjustment value.

  According to this characteristic configuration, by performing feedback control that determines the system voltage command value so that the target field adjustment value matches the target field adjustment value, the target field adjustment value depends on the operating state of the AC motor. And can be controlled to an appropriate value. Here, the target field adjustment value is a field adjustment value for adjusting the direction in which the field magnetic flux is weakened so that the current command value falls within the output possible range. The output range of the current command value includes the system voltage and the alternating current. It is determined based on the rotation speed of the electric motor. Therefore, by appropriately controlling the system voltage according to the operating state of the AC motor such as target torque and rotational speed, the target field adjustment value is adjusted to an appropriate value according to the operating state of the AC motor. can do. Thereby, it becomes possible to raise the efficiency of the whole system including an AC motor and a motor drive device.

  Here, based on the current command value and the rotational speed of the AC motor, a voltage command determination unit that determines an AC voltage command value that is a command value of an AC voltage supplied from the DC / AC converter to the AC motor; An actual modulation rate deriving unit for deriving an actual modulation rate representing the magnitude of the AC voltage command value with respect to the system voltage, and the system voltage determination unit sets the target field adjustment value to the target field adjustment value. It is preferable that the system voltage command value is determined so as to match the value and to match the actual modulation rate with a predetermined target modulation rate.

  According to this configuration, the target field adjustment value is matched with the target field adjustment value and the system voltage command value is determined so as to match the actual modulation rate with the predetermined target modulation rate. While controlling the field adjustment value to be an appropriate value according to the operating state of the AC motor, it is possible to control the actual modulation rate so as to quickly match the target modulation rate. Here, the control mode to be executed by the DC / AC converter may be changed according to the actual modulation rate, and the efficiency of the system may vary depending on the actual modulation rate even within one control mode. According to this configuration, since the target field adjustment value can be controlled to be an appropriate value according to the operating state of the AC motor, the actual modulation rate can be controlled to be an appropriate value quickly. Further, the efficiency of the entire system including the AC motor and the motor drive device can be further increased.

  Further, the apparatus further comprises a mode control unit that selects one of a plurality of control modes including a pulse width modulation control mode and a rectangular wave control mode based on the actual modulation rate and causes the DC / AC conversion unit to execute the mode control unit, The target modulation rate is preferably the value of the actual modulation rate that is a condition for starting the rectangular wave control mode.

  According to this configuration, the target field adjustment value can be matched with the target field adjustment value, and the actual modulation rate can be controlled so as to quickly match the value that is a condition for starting the rectangular wave control mode. Here, in the rectangular wave control mode, since the number of times of switching of the switching element in the DC / AC converter can be significantly reduced as compared with the pulse width modulation control mode, the switching loss can be reduced. Therefore, according to this configuration, the switching loss in the DC / AC converter can be reduced while controlling the target field adjustment value to be an appropriate value according to the operating state of the AC motor. It becomes possible to further increase the efficiency of the entire system including the apparatus.

  Further, the apparatus further comprises a mode control unit that selects one of a plurality of control modes including a pulse width modulation control mode and a rectangular wave control mode based on the actual modulation rate and causes the DC / AC conversion unit to execute the mode control unit, The target modulation rate is a constant value set within the range of the actual modulation rate that is a condition for executing the pulse width modulation control mode when the system voltage is less than the upper limit value of the system voltage command value. In a state where the system voltage is the upper limit value of the system voltage command value, it is preferable that the system voltage is a value that matches the actual modulation rate.

  Usually, the actual modulation rate increases as the rotational speed and torque of the AC motor increase. The pulse width modulation control mode is executed with a relatively low actual modulation rate, and the rectangular wave control mode is executed with a relatively high actual modulation rate. According to this configuration, it is possible to perform field-weakening control that weakens the field magnetic flux even in the pulse width modulation control mode that is executed in a state where the actual modulation rate is relatively low. It can be matched with the adjustment value. Therefore, the target field adjustment value can be adjusted to an appropriate value according to the operating state of the AC motor, and the efficiency of the entire system including the AC motor and the motor driving device can be increased.

  Further, the system voltage command value is obtained by adjusting the current command value determined by the current command determination unit with the target field adjustment value, and a value on the outer edge of the output possible range. It is preferable that it is determined to be.

  According to this configuration, in the configuration in which the field adjustment command value is determined so that the current command value falls within the output possible range, the system voltage command is appropriately set so that the target field adjustment value matches the target field adjustment value. The value can be determined.

  The target field adjustment value is preferably determined so as to increase as one or both of the rotational speed of the AC motor and the target torque of the AC motor increase.

  Normally, in an electric motor, the change in magnetic flux density increases as the rotational speed increases, so the iron loss increases. As the output torque increases, the current flowing through the coil increases and the magnetic flux density increases, so the iron loss increases. To increase. Therefore, as in this configuration, the target field adjustment value is determined to increase as the rotational speed of the AC motor increases, and is determined to increase as the target torque of the AC motor increases. Alternatively, by determining that both the rotation speed and the target torque become higher, the target field adjustment value becomes larger as the situation where the iron loss tends to increase proceeds. Can be controlled. Since the field magnetic flux of the AC motor is weakened as the target field adjustment value becomes larger, the generation of iron loss caused by the field magnetic flux can be suppressed. Thereby, it becomes possible to raise the efficiency of the whole system including an AC motor and a motor drive device.

  The motor driving device includes a plurality of the DC / AC converters corresponding to each of the plurality of AC motors, and one voltage converter common to the plurality of DC / AC converters, and the voltage The converter is configured to generate the system voltage common to the plurality of DC / AC converters, and corresponding to each of the plurality of DC / AC converters, a plurality of the current command determining units, and a plurality of A plurality of voltages that determine an AC voltage command value that is a command value of an AC voltage supplied from the DC / AC converter to the AC motor based on the field adjustment unit and the current command value and the rotational speed of the AC motor. A command determining unit; and a plurality of actual modulation rate deriving units for deriving an actual modulation rate representing the magnitude of the AC voltage command value with respect to the system voltage, the target field adjustment value acquiring unit, the target field Adjustment The determination unit and the system voltage determination unit include the DC / AC conversion unit in which the actual modulation rate derived by the corresponding actual modulation rate deriving unit is the largest among the plurality of DC / AC conversion units. It is preferable that the system voltage command value that operates as a target and is common to the plurality of DC / AC converters is determined.

  According to this configuration, even when the motor drive device includes a plurality of DC / AC conversion units corresponding to the plurality of AC motors, an appropriate system voltage can be generated by controlling one voltage conversion unit. . That is, the iron loss is greatest in the DC / AC converter and the AC motor having the largest actual modulation rate among the plurality of sets of DC / AC converters and AC motors. Therefore, by appropriately adjusting the target field adjustment value in such a DC / AC converter and an AC motor to suppress the occurrence of iron loss, an electric motor drive having a plurality of AC motors and a plurality of DC / AC converters The efficiency of the entire system including the device can be increased.

It is a circuit diagram which shows the structure of the electric motor drive device which concerns on embodiment of this invention. It is a skeleton figure which shows the structure of the vehicle drive device which concerns on embodiment of this invention. It is a functional block diagram of the inverter control command determination unit with which the control apparatus which concerns on 1st embodiment of this invention is provided. It is a functional block diagram of the voltage conversion instruction | command determination unit with which the control apparatus which concerns on 1st embodiment of this invention is provided. It is a figure which shows the example of the control mode selection map which concerns on embodiment of this invention. It is a figure which shows the example of the electric current command value map which concerns on embodiment of this invention. It is a figure which shows the example of the target field adjustment value map which concerns on embodiment of this invention. It is explanatory drawing of the determination process of the system voltage command value using the current command value map based on 1st Embodiment of this invention. It is a time chart which shows the operation example of the control apparatus based on 1st embodiment of this invention. It is explanatory drawing of the determination process of the system voltage command value using the current command value map based on 2nd embodiment of this invention. It is a time chart which shows the operation example of the control apparatus based on 2nd embodiment of this invention. It is a functional block diagram of the voltage conversion command determination unit with which the control apparatus which concerns on 3rd embodiment of this invention is provided. It is a flowchart which shows the target modulation factor determination process which concerns on 3rd embodiment of this invention. It is explanatory drawing of the determination process of the system voltage command value using the current command value map based on 3rd embodiment of this invention. It is a time chart which shows the operation example of the control apparatus based on 3rd embodiment of this invention.

1. First Embodiment First, a first embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 2, in this embodiment, the case where the electric motor drive device 2 is configured as a device for driving two electric motors MG1 and MG2 used as a drive force source of the hybrid vehicle drive device 80. This will be described as an example. Therefore, as shown in FIG. 1, the electric motor drive device 2 according to the present embodiment includes two inverters 5 and 6 corresponding to the two electric motors MG1 and MG2, and one common to the two inverters 5 and 6, respectively. The voltage converter 4 is configured to generate a system voltage Vdc common to the two inverters 5 and 6. Here, the voltage conversion unit 4 can be configured to either increase or decrease the power supply voltage Vb, or can be configured to increase or decrease the voltage, but in this embodiment, the voltage conversion unit 4 A case will be described in which is configured to only boost the power supply voltage Vb.

1-1. Schematic Configuration of Vehicle Drive Device First, a schematic configuration of a vehicle drive device 80 according to the present embodiment will be described with reference to FIG. The vehicle drive device 80 includes an internal combustion engine E and a pair of electric motors MG1 and MG2 as a driving force source. And for the so-called two-motor split type hybrid vehicle provided with a differential gear device 81 for power distribution that distributes the output of the internal combustion engine E to the first electric motor MG1 side and the wheels W and the second electric motor MG2 side. It is comprised as a drive device.

  This vehicle drive device 80 has a drive force applied to an input shaft 82 connected to the internal combustion engine E, a power distribution differential gear device 81, a counter gear mechanism 83, and a plurality of wheels W as a power transmission system. And an output differential gear device 84 for distributing the power. Here, the power distribution differential gear device 81 is configured by a single pinion type planetary gear mechanism. The power distribution differential gear device 81 outputs the output (driving force) of the internal combustion engine E transmitted to the carrier via the input shaft 82 to the first motor MG1 coupled to the sun gear and the counter coupled to the ring gear. Distribute to drive gear 85. The counter drive gear 85 meshes with the gear of the counter gear mechanism 83 and is drivingly connected to the counter gear mechanism 83. Second motor MG2 is drivingly connected to counter gear mechanism 83 with second motor output gear 86 meshing with the gear of counter gear mechanism 83. The counter gear mechanism 83 meshes with the input gear 87 of the output differential gear device 84 and is drivingly connected to the output differential gear device 84. As a result, the driving force of the internal combustion engine E and the first electric motor MG1 and the driving force of the second electric motor MG2 output from the power distribution differential gear device 81 are transmitted to the wheels W.

  In the present embodiment, each of the first motor MG1 and the second motor MG2 is an AC motor that operates by three-phase AC, and is a synchronous motor (IPMSM) having an embedded magnet structure. These electric motors MG1 and MG2 are configured to operate as a generator as required. The first electric motor MG1 includes a stator St1 fixed to a case (not shown) and a rotor Ro1 that is rotatably supported on the radially inner side of the stator St1. The second electric motor MG2 includes a stator St2 fixed to a case (not shown), and a rotor Ro2 that is rotatably supported on the radially inner side of the stator St2.

1-2. Configuration of Electric Motor Drive Device Next, the configuration of the electric motor drive device 2 according to the present embodiment will be described with reference to FIG. In the present embodiment, the electric motor drive device 2 is configured as a device that drives the two electric motors MG1 and MG2. Therefore, the electric motor drive device 2 includes two inverters, a first inverter 5 corresponding to the first electric motor MG1 and a second inverter 6 corresponding to the second electric motor MG2. In the present embodiment, each of these two inverters 5 and 6 corresponds to a DC / AC converter in the present invention. Further, the electric motor drive device 2 includes one voltage conversion unit 4 common to the two inverters 5 and 6. The voltage converter 4 is configured to generate a system voltage Vdc common to the two inverters 5 and 6. The electric motor drive device 2 also includes a DC power source 3, a first smoothing capacitor Q 1 that smoothes the power source voltage Vb from the DC power source 3, and a second smoothing that smoothes the system voltage Vdc that has been boosted by the voltage converter 4. And a capacitor Q2. The DC power source 3 is configured to be able to supply electric power to the electric motors MG1 and MG2 via the voltage conversion unit 4 and the two inverters 5 and 6, and to be able to store electric power obtained by the electric power generation by the electric motors MG1 and MG2. ing. As such a DC power source 3, for example, various secondary batteries such as a nickel hydride secondary battery and a lithium ion secondary battery, a capacitor, or a combination thereof is used. A power supply voltage Vb, which is a voltage of the DC power supply 3, is detected by the power supply voltage sensor 61 and output to the control device 1.

  The voltage converter 4 is configured as a DC-DC converter that converts the power supply voltage Vb from the DC power supply 3 to generate a desired system voltage Vdc. In the present embodiment, the voltage converter 4 is a boost converter that boosts the power supply voltage Vb. When the electric motors MG1 and MG2 function as a generator, the system voltage Vdc from the inverters 5 and 6 is stepped down and supplied to the DC power source 3 to charge the DC power source 3. The voltage conversion unit 4 includes a reactor L1 and voltage conversion switching elements E1 and E2. Here, the voltage conversion unit 4 includes a pair of upper arm element E1 and lower arm element E2 connected in series as voltage conversion switching elements. In these examples, IGBTs (insulated gate bipolar transistors) are used as the voltage conversion switching elements E1 and E2. The emitter of the upper arm element E1 and the collector of the lower arm element E2 are connected to the positive terminal of the DC power supply 3 via the reactor L1. The collector of the upper arm element E1 is connected to a system voltage line 67 to which the voltage boosted by the voltage converter 4 is supplied, and the emitter of the lower arm element E2 is a negative line 68 connected to the negative terminal of the DC power supply 3. It is connected to the. Free-wheel diodes D1 and D2 are connected in parallel to the voltage conversion switching elements E1 and E2, respectively. As the voltage conversion switching elements E1 and E2, in addition to the IGBT, power transistors having various structures such as a bipolar type, a field effect type, and a MOS type can be used.

  Each of the voltage conversion switching elements E1 and E2 operates according to the voltage conversion control signals S1 and S2 output from the control device 1. In the present embodiment, the voltage conversion control signals S1 and S2 are switching control signals for controlling the switching of the switching elements E1 and E2, more specifically, gate driving signals for driving the gates of the switching elements E1 and E2. As a result, the voltage conversion unit 4 boosts the power supply voltage Vb supplied from the DC power supply 3 to a desired system voltage Vdc and supplies the boosted voltage to the first inverter 5 and the second inverter 6 via the system voltage line 67. The system voltage Vdc generated by the voltage conversion unit 4 is detected by the system voltage sensor 62 and output to the control device 1. When voltage boosting by voltage converter 4 is not performed, system voltage Vdc is equal to power supply voltage Vb.

  The first inverter 5 is a device for converting DC power having the system voltage Vdc into AC power and supplying it to the first electric motor MG1. The first inverter 5 is configured by a bridge circuit and includes a plurality of sets of switching elements E3 to E8. Here, the first inverter 5 includes a pair of switching elements for each phase (three phases of U phase, V phase, and W phase) of the first electric motor MG1, specifically, an upper arm element E3 for U phase and A U-phase lower arm element E4, a V-phase upper arm element E5, a V-phase lower arm element E6, a W-phase upper arm element E7, and a W-phase lower arm element E8 are provided. In these examples, IGBTs (insulated gate bipolar transistors) are used as the switching elements E3 to E8. The emitters of the upper arm elements E3, E5, and E7 for each phase and the collectors of the lower arm elements E4, E6, and E8 are connected to the coils of the respective phases of the first electric motor MG1. The collectors of the upper arm elements E3, E5, E7 for each phase are connected to the system voltage line 67, and the emitters of the lower arm elements E4, E6, E8 for each phase are connected to the negative line 68. Free wheel diodes D3 to D8 are connected in parallel to the switching elements E3 to E8, respectively. As the switching elements E3 to E8, power transistors having various structures such as a bipolar type, a field effect type, and a MOS type can be used in addition to the IGBT.

  Each of switching elements E3 to E8 operates in accordance with first inverter control signals S3 to S8 output from control device 1. In the present embodiment, the first inverter control signals S3 to S8 are switching control signals for controlling the switching of the switching elements E3 to E8, more specifically, gate driving signals for driving the gates of the switching elements E3 to E8. . Thereby, the first inverter 5 converts the system voltage Vdc into an AC voltage and supplies it to the first electric motor MG1, and causes the first electric motor MG1 to output a torque corresponding to the target torque TM. At this time, each of the switching elements E3 to E8 enters a control mode such as a pulse width modulation control mode (hereinafter referred to as “PWM control mode”) CP or a rectangular wave control mode C4, which will be described later, according to the first inverter control signals S3 to S8. Performs the corresponding switching operation. Further, when the first electric motor MG1 functions as a generator, the first inverter 5 converts AC power obtained by power generation into DC power and supplies it to the voltage converter 4 via the system voltage line 67. .

  The second inverter 6 is a device for converting DC power having the system voltage Vdc into AC power and supplying it to the second electric motor MG2. The second inverter 6 has substantially the same configuration as the first inverter 5 described above. That is, the second inverter 6 is configured by a bridge circuit and includes a plurality of sets of switching elements E9 to E14. The emitters of the upper arm elements E9, E11, E13 for each phase and the collectors of the lower arm elements E10, E12, E14 are connected to the coils of the respective phases of the second electric motor MG2. The collectors of the upper arm elements E9, E11, E13 for each phase are connected to the system voltage line 67, and the emitters of the lower arm elements 10, E12, E14 for each phase are connected to the negative line 68. Further, free wheel diodes D9 to D14 are connected in parallel to the switching elements E9 to E14, respectively. And each of switching element E9-E14 operate | moves according to 2nd inverter control signal S9-S14 output from the control apparatus 1. FIG. Thereby, the second inverter 6 converts the system voltage Vdc into an AC voltage and supplies it to the second electric motor MG2, and causes the second electric motor MG2 to output a torque corresponding to the target torque TM.

  The actual current Ir1 flowing between the first inverter 5 and each phase coil of the first electric motor MG1 is detected by the first current sensor 63, and between the second inverter 6 and each phase coil of the second electric motor MG2. The flowing actual current Ir2 is detected by the second current sensor 64 and output to the control device 1 respectively. Here, the actual currents Ir1 and Ir2 include an actual U-phase current, an actual V-phase current, and an actual W-phase current corresponding to three phases. In this example, a configuration is shown in which all three-phase currents are detected. However, since the three phases are in an equilibrium state and the sum of instantaneous current values is zero, only two-phase currents are detected by a sensor. In the control device 1, the remaining one-phase current may be obtained by calculation. The magnetic pole position θ1 at each time point of the rotor Ro1 of the first electric motor MG1 is detected by the first rotation sensor 65, and the magnetic pole position θ2 at each time point of the rotor Ro2 of the second electric motor MG2 is detected by the second rotation sensor 66. And output to the control device 1 respectively. The rotation sensors 65 and 66 are constituted by, for example, a resolver. Here, the magnetic pole positions θ1 and θ2 represent the rotation angles of the rotors Ro1 and Ro2 on the electrical angle. The target torque TM1 of the first motor MG1 and the target torque TM2 of the second motor MG2 are input to the control device 1 as request signals from other control devices such as a vehicle control device (not shown).

1-3. Configuration of Control Device Next, the configuration of the control device 1 that controls the electric motor drive device 2 will be described in detail with reference to FIGS. Each functional unit of the control device 1 described below is based on hardware and / or software (program) or both for performing various processes on input data using a logic circuit such as a microcomputer as a core member. It is configured. In the present embodiment, the control device 1 performs current feedback control using the vector control method of the electric motors MG1 and MG2 via the inverters 5 and 6. In addition, the control device 1 performs DC voltage conversion control for controlling the voltage converter 4 to generate a desired system voltage Vdc. As described above, the control device 1 has the two inverters 5 and 6 corresponding to the two electric motors MG1 and MG2 as control targets. Therefore, two inverter control command determination units 7 (FIG. 3), which are a first inverter control command determination unit 71 for controlling the first inverter 5 and a second inverter control command determination unit 72 for controlling the second inverter 6. See). Moreover, since the control apparatus 1 has one voltage conversion part 4 as control object, it is provided with the one voltage conversion command determination unit 8 (refer FIG. 4) corresponding to it.

  The control device 1 generates and outputs voltage conversion control signals S1 and S2 for driving the voltage conversion unit 4, converts the power supply voltage Vb (in this case, boosts it), and supplies it to the two inverters 5 and 6 The system voltage is controlled to be generated. The control device 1 generates and outputs first inverter control signals S3 to S8 for driving the first inverter 5 and second inverter control signals S9 to S14 for driving the second inverter 6, Drive control of the two electric motors MG1 and MG2 is performed via the inverters 5 and 6, respectively. At this time, the control device 1 selects one of a plurality of control modes and causes the inverters 5 and 6 to execute it. In the present embodiment, as shown in FIG. 5, the control device 1 causes the inverters 5 and 6 to perform normal PWM control together with normal field control (maximum torque control) in accordance with an actual modulation rate M described later. Control mode C1, first overmodulation PWM control mode C2 in which each inverter 5 and 6 performs overmodulation PWM control together with normal field control, and second overmodulation PWM in which each inverter 5 and 6 performs overmodulation PWM control together with field weakening control The control mode C3 and each of the inverters 5 and 6 are selectively caused to execute any one of four control modes of a rectangular wave control mode C4 in which rectangular wave control is performed together with field weakening control. Details of each control mode will be described later.

1-3-1. Next, the configuration of the inverter control command determination unit 7 will be described. As described above, the control device 1 includes the two inverter control command determination units 71 and 72 corresponding to the two inverters 5 and 6, respectively. Here, since the functions of the first inverter control command determination unit 71 and the second inverter control command determination unit 72 are almost the same as each other, hereinafter, only the “inverter control command determination unit 7” is used unless particularly distinguished. Will be described. At this time, values that are input to and output from the inverter control command determination units 71 and 72 are also expressed using common symbols. Specifically, the first magnetic pole position θ1 which is the magnetic pole position of the first electric motor MG1 and the second magnetic pole position θ2 which is the magnetic pole position of the second electric motor MG2 are “magnetic pole position θ”, which is an actual current flowing through the first electric motor MG1. The first actual current Ir1 and the second actual current Ir2 that is the actual current flowing through the second motor MG2 are “actual current Ir”, the first target torque TM1 that is the target torque of the first motor MG1, and the target of the second motor MG2. The second target torque TM2 that is the torque is expressed as “target torque TM”. The first rotation speed ω1 that is the rotation speed of the first electric motor MG1 and the second rotation speed ω2 that is the rotation speed of the second electric motor MG2 are “rotation speed ω”, which is the basic output from the first inverter control command determination unit 71. The first basic d-axis current command value Id1 that is the d-axis current command value and the second basic d-axis current command value Id2 that is the basic d-axis current command value output from the second inverter control command determination unit 72 are “d-axis current”. Command value Id ”, the first actual d-axis current Idr1 that is the actual d-axis current output from the first inverter control command determination unit 71, and the second actual d-axis current that is output from the second inverter control command determination unit 72. The d-axis current Idr2 is “actual d-axis current Idr”, the first actual modulation factor M1 that is the actual modulation factor output from the first inverter control command determination unit 71, and the second inverter control command. Second actual modulation factor M2 is a real modulation rate to be output from the constant unit 72 is referred to as "actual modulation factor M".

  FIG. 3 shows a functional block diagram of the inverter control command determination unit 7. The inverter control command determination unit 7 performs current feedback control using a current vector control method. In the current vector control method, the magnetic flux direction of the rotating field is set as the d-axis, and the direction advanced by π / 2 in electrical angle with respect to the direction of the field is set as the q-axis. Then, based on the target torque TM of the electric motors MG1 and MG2 to be controlled, the current command values for the d-axis and the q-axis are determined, and the current actually supplied to the electric motors MG1 and MG2 is detected and feedback control is performed. This causes the electric motors MG1 and MG2 to output the target torque TM. Hereinafter, processing in the inverter control command determination unit 7 will be described.

  As shown in FIG. 3, the target torque TM of the electric motors MG <b> 1 and MG <b> 2 to be controlled is input to the current command determination unit 11. Based on the target torque TM, the current command determination unit 11 determines a current command value that is a command value of a current supplied from the inverters 5 and 6 to the electric motors MG1 and MG2. Here, the current command value includes a d-axis current command value Id and a q-axis current command value Iq. The current command values Id and Iq should be referred to as basic current command values, and when performing basic field control (hereinafter referred to as normal field control) in which field adjustment such as field weakening is not performed, the target torque TM Is a command value for d-axis current and q-axis current derived to output. Hereinafter, in order to differentiate from the adjusted current command values Ida and Iqa, which are current command values after adjustment based on a field adjustment command value ΔId, which will be described later, the current command value when performing normal field control is the basic current command value Id. , Iq (basic d-axis current command value Id and basic q-axis current command value Iq). The basic current command values Id and Iq correspond to the current command values in the present invention. In the present embodiment, maximum torque control is performed as the normal field control. Here, the maximum torque control is a control for adjusting the current phase so that the output torque of the electric motors MG1 and MG2 is maximized with respect to the same current. In this maximum torque control, torque can be generated most efficiently with respect to the current flowing through the armature coils of the electric motors MG1 and MG2. The current phase is a phase with respect to the q-axis of a combined vector of the d-axis current command value and the q-axis current command value. The normal field control is control in which field adjustment is not performed on the basic current command values Id and Iq, and a field adjustment command value ΔId described later becomes zero (ΔId = 0) during the normal field control.

  In addition, the current command determination unit 11 adjusts the d-axis current command value Ida after adjustment and the post-adjustment after the field command value ΔId is applied to the basic current command values Id and Iq. The q-axis current command value Iqa is also determined. The field adjustment command value ΔId is a field adjustment value command value for adjusting the direction in which the field magnetic flux of the electric motors MG1, MG2 is weakened with respect to the basic current command values Id, Iq. A method for deriving the field adjustment command value ΔId will be described later.

  The current command determination unit 11 determines a basic d-axis current command value Id and a basic q-axis current command value Iq based on a current command value map as shown in FIG. In FIG. 6, a thin solid line is an equal torque line 101 indicating values of d-axis current and q-axis current for outputting torques TM-1 to TM-5, and a thick solid line is a maximum torque as normal field control. It is the maximum torque control line 102 which shows the value of d-axis current and q-axis current for performing control. In FIG. 6, the thick alternate long and short dash line is a voltage limiting ellipse 103 indicating a range of values that can be taken by the d-axis current and the q-axis current limited by the rotational speed ω of the motors MG1 and MG2 and the system voltage Vdc at that time. is there. The diameter of the voltage limiting ellipse 103 is inversely proportional to the rotational speed ω of the electric motors MG1 and MG2, and is proportional to the system voltage Vdc. That is, the diameter of the voltage limiting ellipse 103 decreases as the rotational speed ω increases, and increases as the system voltage Vdc increases. When the adjusted current command values Ida and Iqa take values on the voltage limit ellipse 103, the actual modulation rate M is the target modulation rate MT corresponding to the maximum value of the actual modulation rate M that can be taken at that time. Become. In the present embodiment, the target modulation rate MT is set to the theoretical maximum modulation rate Mmax (= 0.78) that can be realized in a system including the motors MG1 and MG2 and the motor drive device 2. Therefore, when the adjusted current command values Ida and Iqa take values on the voltage limit ellipse 103, the control device 1 causes the inverters 5 and 6 to execute the rectangular wave control mode C4. This voltage limiting ellipse 103 is the outer edge of the current command value output possible range in the present invention.

  Based on the current command value map shown in FIG. 6, the current command determination unit 11 determines the d-axis and q corresponding to the coordinates of the intersection of the equal torque line 101 and the maximum torque control line 102 corresponding to the input target torque TM. The axis values are determined as the basic d-axis current command value Id and the basic q-axis current command value Iq. In the example illustrated in FIG. 6, when a value “TM-2” is input as the target torque TM, the current command determination unit 11 determines that the target torque TM = TM−2 equal torque line 101 and the maximum torque control line 102. (Id1, Iq1) are determined as the basic d-axis current command value Id and the basic q-axis current command value Iq. Since (Id1, Iq1) is inside the voltage limiting ellipse 103 and field-weakening control is not performed, the field adjustment command value ΔId is zero (ΔId = 0), and the field for the basic current command values Id, Iq is Magnetic adjustment is not performed. Therefore, in this case, the adjusted current command values Ida and Iqa are the same values as the basic current command values Id and Iq. In this case, the control device 1 causes the inverters 5 and 6 to execute the normal PWM control mode C1.

On the other hand, when a value of “TM-5” is input as the target torque TM, the current command determination unit 11 is an intersection of the equal torque line 101 and the maximum torque control line 102 of the target torque TM = TM-5 ( Id2, Iq2) are determined as the basic d-axis current command value Id and the basic q-axis current command value Iq. Since (Id2, Iq2) is outside the voltage limiting ellipse 103 and such a current command value cannot be obtained, the field adjustment command value ΔId is used to weaken the field magnetic flux of the motors MG1 and MG2 to be weakened. Field control is performed. In the illustrated example, “ΔId1” (ΔId1 <0) is input from the integrator 23 described later as the field adjustment command value ΔId. Therefore, the current command determination unit 11 calculates “ΔId1” in the negative direction along the d-axis along the equal torque line 101 of the target torque TM = TM-5 from the basic current command values Id and Iq (Id2, Iq2). The d-axis and q-axis values (Id3, Iq3) corresponding to the coordinates on the voltage limit ellipse 103 moved by "are determined as the adjusted d-axis current command value Ida and the adjusted q-axis current command value Iqa. In this case, the control device 1 causes the inverters 5 and 6 to execute the rectangular wave control mode C4. The adjusted d-axis current command value Ida corresponds to a value obtained by adding the field adjustment command value ΔId to the basic d-axis current command value Id, and is expressed by the following equation (1).
Ida = Id + ΔId (1)

  By the way, in the present embodiment, the control device 1 is configured to execute the second overmodulation PWM control mode C3 in which the inverters 5 and 6 perform overmodulation PWM control together with field weakening control. Therefore, as will be described later, even when the actual modulation rate M is less than the target modulation rate MT and the basic current command values Id and Iq are inside the voltage limit ellipse 103, the field weakening control by the field adjustment command value ΔId is performed. May be executed. For example, as illustrated in FIG. 6, when a value “TM-4” is input as the target torque TM, the current command determination unit 11 determines that the equal torque line 101 and the maximum torque control line with the target torque TM = TM-4. (Id4, Iq4), which is an intersection with 102, is determined as a basic d-axis current command value Id and a basic q-axis current command value Iq. This (Id4, Iq4) is inside the voltage limit ellipse 103, but is located very close to the voltage limit ellipse 103. In such a case as well, field weakening control by the field adjustment command value ΔId is performed. In the illustrated example, “ΔId2” (ΔId2 <0) is input from the integrator 23 described later as the field adjustment command value ΔId. Therefore, the current command determination unit 11 calculates “ΔId2” in the negative direction along the d axis along the equal torque line 101 of the target torque TM = TM-4 from the basic current command values Id and Iq (Id4, Iq4). The d-axis and q-axis values (Id5, Iq5) moved by “are determined as the adjusted d-axis current command value Ida and the adjusted q-axis current command value Iqa. In this case, the control device 1 causes the inverters 5 and 6 to execute the second overmodulation PWM control mode C3.

  The adjusted d-axis current command value Ida and the adjusted d-axis current command value Ida derived as described above are input to the current control unit 16. Furthermore, the actual d-axis current Idr and the actual q-axis current Iqr are input to the current control unit 16 from the three-phase to two-phase conversion unit 19, and the rotation speed ω of the target motors MG1 and MG2 is determined from the rotation speed deriving unit 20. Entered. The actual d-axis current Idr and the actual q-axis current Iqr are detected by the actual currents Ir (Ir1, Ir2) detected by the current sensors 63 and 64 (see FIG. 1) and the rotation sensors 65 and 66 (see FIG. 1). Based on the magnetic pole position θ (θ1, θ2), the three-phase to two-phase converter 19 performs three-phase to two-phase conversion. Further, the rotational speed ω (ω1, ω2) of the electric motors MG1, MG2 is derived by the rotational speed deriving unit 20 based on the magnetic pole position θ (θ1, θ2) detected by the rotation sensors 65, 66.

  The current control unit 16 calculates a d-axis current deviation δId that is a deviation between the adjusted d-axis current command value Ida and the actual d-axis current Idr, and a deviation between the adjusted d-axis current command value Ida and the actual q-axis current Iqr. A certain q-axis current deviation δIq is derived. Then, the current control unit 16 performs a proportional integration control calculation (PI control calculation) based on the d-axis current deviation δId to derive a basic d-axis voltage command value Vzd, and also performs proportional integration based on the q-axis current deviation δIq. A control calculation is performed to derive a basic q-axis voltage command value Vzq. Note that it is also preferable to perform a proportional integral derivative control calculation (PID control calculation) instead of these proportional integral control calculations.

Then, as shown in the following equation (2), the current control unit 16 performs adjustment to subtract the q-axis armature reaction Eq from the basic d-axis voltage command value Vzd to derive the d-axis voltage command value Vd. To do.
Vd = Vzd-Eq
= Vzd-ω · Lq · Iqr (2)
As shown in this equation (2), the q-axis armature reaction Eq is derived based on the rotational speed ω, the actual q-axis current Iqr, and the q-axis inductance Lq of the electric motors MG1 and MG2.

Furthermore, the current control unit 16 adds the induced voltage Em caused by the d-axis armature reaction Ed and the armature interlinkage magnetic flux of the permanent magnet to the basic q-axis voltage command value Vzq as shown in the following equation (3). Thus, the q-axis voltage command value Vq is derived.
Vq = Vzq + Ed + Em
= Vzq + ω · Ld · Idr + ω · Mif (3)
As shown in Equation (3), the d-axis armature reaction Ed is derived based on the rotational speed ω, the actual d-axis current Idr, and the d-axis inductance Ld of the electric motors MG1 and MG2. The induced voltage Em is derived based on the induced voltage constant MIf determined by the effective value of the armature linkage magnetic flux of the permanent magnet and the rotational speed ω of the electric motors MG1 and MG2.

  In the present embodiment, the d-axis voltage command value Vd and the q-axis voltage command value Vq correspond to the AC voltage command value in the present invention. The adjusted current command values Ida, Iqa after the field adjustment by the field adjustment command value ΔId with respect to the basic current command values Id, Iq, the rotational speed ω of the motors MG1, MG2, and the actual d axis AC voltage command values Vd and Vq are determined based on current Idr and actual q-axis current Iqr. Therefore, the current command determination unit 11 and the current control unit 16 constitute a voltage command determination unit 13 in the present invention.

The actual modulation rate deriving unit 14 receives the d-axis voltage command value Vd and the q-axis voltage command value Vq derived by the current control unit 16. Further, the value of the system voltage Vdc detected by the system voltage sensor 62 is input to the actual modulation factor deriving unit 14. Based on these values, the actual modulation rate deriving unit 14 derives the actual modulation rate M according to the following equation (4).
M = √ (Vd ² + Vq ² ) / Vdc (4)
This actual modulation factor M is the ratio of the effective value of the fundamental wave component of the output voltage waveform of the inverters 5 and 6 to the system voltage Vdc. Here, the effective value of the three-phase line voltage is divided by the value of the system voltage Vdc. Is derived as a value. That is, the actual modulation factor M is a voltage index representing the magnitudes of the AC voltage command values Vd and Vq with respect to the system voltage Vdc at that time. The maximum modulation rate Mmax, which is the maximum value of the actual modulation rate M, is “0.78” corresponding to the actual modulation rate M when rectangular wave control is executed as voltage waveform control described later.

The actual modulation rate M derived by the actual modulation rate deriving unit 14 and the target modulation rate MT are input to the subtractor 21. The subtractor 21 derives a modulation factor deviation ΔM obtained by subtracting the target modulation factor MT from the actual modulation factor M, as shown in the following equation (5).
ΔM = M−MT (5)
In the present embodiment, the modulation factor deviation ΔM represents the degree to which the AC voltage command values Vd and Vq exceed the maximum AC voltage value that can be output by the system voltage Vdc at that time. Therefore, the modulation factor deviation ΔM substantially functions as a voltage shortage index that represents the degree of shortage of the system voltage Vdc.

  The integral deviation adjusting unit 22 receives the modulation factor deviation ΔM derived by the subtractor 21. The integral input adjustment unit 22 performs a predetermined adjustment on the value of the modulation factor deviation ΔM, and outputs an adjustment value Y that is the adjusted value to the integrator 23. As shown in FIG. 3, in this embodiment, the integral input adjustment unit 22 is in a state (ΔM ≦ ΔMs) in which the modulation factor deviation ΔM is equal to or less than the field weakening threshold value ΔMs (ΔMs <0) (ΔM ≦ ΔMs). = 0), zero (Y = 0) is output as the adjustment value Y, and in a state where the modulation factor deviation ΔM is larger than the predetermined field-weakening start threshold value ΔMs (ΔMs ≦ ΔM), the negative adjustment value Y (Y < 0) is output. More specifically, the integral input adjustment unit 22 outputs an adjustment value Y that decreases as the modulation factor deviation ΔM increases in a state where the modulation factor deviation ΔM is greater than the field weakening start threshold value ΔMs (ΔMs ≦ ΔM). . In this example, the relationship between the modulation factor deviation ΔM and the adjustment value Y at this time can be expressed by a linear function. Thus, by setting the conversion map region in which the adjustment value Y decreases as the modulation factor deviation ΔM increases, the absolute value of the field adjustment command value ΔId increases as the actual modulation factor M increases, and field weakening control is performed. Control for increasing the field-weakening current amount for execution can be appropriately performed. At this time, by setting the field weakening start threshold value ΔMs to a negative value, the field adjustment command value ΔId is output before the actual modulation rate M reaches the target modulation rate MT to start field weakening control. Thus, the second overmodulation PWM control mode C3 is realized. This field weakening start threshold value ΔMs constitutes a starting condition for field weakening control together with the target modulation factor MT. In the present embodiment, the field weakening start threshold value ΔMs is set to “−0.04”. Therefore, as will be described later, when the actual modulation rate M is “Mmax + ΔMs = 0.78−0.04 = 0.74” or more, the second overmodulation PWM control mode C3 for performing field-weakening control is selected. Yes. Note that the value of the field weakening start threshold value ΔMs is merely an example, and can naturally be set to another value. In the present embodiment, the field weakening start threshold value ΔMs is set to “−0.073 in order to start field weakening control when the actual modulation rate M is any value between“ 0.707 and 0.78 ”. It is preferable to set a value between “0” and “0”.

  The adjustment value Y derived by the integration input adjustment unit 22 is input to the integrator 23. The integrator 23 integrates the adjustment value Y using a predetermined gain, and derives the integration value as a field adjustment command value ΔId. The field adjustment command value ΔId is a field adjustment value command value for adjusting the direction in which the field magnetic flux of the electric motors MG1, MG2 is weakened with respect to the basic current command values Id, Iq. Field adjustment command value ΔId is within an output possible range in which adjusted current command values Ida, Iqa after adjustment with respect to basic current command values Id, Iq are determined based on system voltage Vdc and rotation speed ω of electric motors MG1, MG2. To be determined. Here, the output possible range of the current command values (basic current command values Id and Iq and adjusted current command values Ida and Iqa) is a range in which the outer edge is defined by the voltage limit ellipse 103 shown in FIG. 6, that is, the voltage limit ellipse. 103 is limited to the area inside 103. The voltage limit ellipse 103 is a line indicating the values of the d-axis current and the q-axis current at which the actual modulation factor M matches the target modulation factor MT. Therefore, the output possible range of the adjusted current command values Ida and Iqa defined by the voltage limit ellipse 103 is also defined by the target modulation factor MT. The field adjustment command value ΔId is determined by the actual modulation factor deriving unit 14, the subtractor 21, the integral input adjusting unit 22, and the integrator 23. Therefore, in the present embodiment, the field modulation unit 12 is configured by the actual modulation rate derivation unit 14, the subtractor 21, the integral input adjustment unit 22, and the integrator 23. When the field adjustment command value ΔId is zero (ΔId = 0), normal field control (maximum torque control) is performed. In the state where the field adjustment command value ΔId is a negative value (ΔId <0), field weakening control for weakening the field magnetic flux of the electric motors MG1, MG2 is executed.

  The mode control unit 15 is selected by selecting one of a plurality of control modes based on the actual modulation rate M and operating the three-phase command value deriving unit 17 and the inverter control signal generating unit 18 accordingly. The control mode is executed by the inverters 5 and 6. Therefore, the actual modulation rate M is input to the mode control unit 15. In the present embodiment, as shown in FIG. 5, a predetermined control mode is selected according to the actual modulation rate M derived by the actual modulation rate deriving unit 14. At this time, the mode control unit 15 controls the normal PWM control mode C1, the first overmodulation PWM control mode C2, the second overmodulation PWM control mode C3, and the rectangular wave control mode C4 in this order as the actual modulation rate M increases. Transition modes. In the present embodiment, modes C1 to C3 correspond to the PWM control mode CP in the present invention. In the present embodiment, the control device 1 is configured to be able to execute PWM control (normal PWM control, overmodulation PWM control) and rectangular wave control with respect to voltage waveform control performed by controlling switching patterns in the inverters 5 and 6. With respect to the field control for adjusting the field magnetic fluxes of MG1 and MG2, normal field control and field weakening control can be executed. The plurality of control modes C1 to C4 are configured by combining these voltage waveform control and field control.

  In PWM control, the switching elements E3 to E8 (E9 to E14) of the inverter 5 (6) are turned on / off based on the three-phase AC voltages Vu, Vv, and Vw (see FIG. 3) based on the AC voltage command values Vd and Vq. Control. Specifically, the PWM waveform, which is the output voltage waveform of the inverter 5 (6) for each phase of U, V, and W, is high when the upper arm elements E3, E5, E7 (E9, E11, E13) are turned on. It is composed of a set of pulses composed of a level period and a low level period in which the lower arm elements E4, E6, E8 (E10, E12, E14) are turned on, and its fundamental component is substantially constant over a certain period. The duty ratio of each pulse is controlled so as to have a sine wave shape. In the present embodiment, the PWM control includes two control methods of normal PWM control and overmodulation PWM control.

  The normal PWM control is PWM control in which the AC voltage waveforms Vu, Vv, and Vw are less than or equal to the amplitude of the carrier waveform (triangular wave). As such normal PWM control, sine wave PWM control is typical, but in this embodiment, a space vector PWM (applying a neutral point bias voltage to the fundamental wave of each phase of sine wave PWM control. Space Vector PWM (hereinafter referred to as “SVPWM”) control is used. In the SVPWM control, the PWM waveform is directly generated by digital calculation without being compared with the carrier, but even in this case, the AC voltage waveforms Vu, Vv, and Vw are less than the amplitude of the virtual carrier waveform. In the present invention, such a method of generating a PWM waveform without using a carrier is also included in normal PWM control or overmodulation PWM control in comparison with the amplitude of a virtual carrier waveform. In the SVPWM control as the normal PWM control, the actual modulation factor M can be changed in the range of “0 to 0.707”.

  The overmodulation PWM control is PWM control in which the amplitude of the AC voltage waveforms Vu, Vv, and Vw exceeds the amplitude of the carrier waveform (triangular wave). In overmodulation PWM control, the waveform of the fundamental wave component of the output voltage waveform of inverters 5 and 6 is distorted by making the duty ratio of each pulse large on the peak side of the fundamental wave component and smaller on the valley side than in normal PWM control. However, the amplitude is controlled so as to be larger than the normal PWM control. In the overmodulation PWM control, the actual modulation rate M can be changed in a range of “0.707 to 0.78”.

  In the rectangular wave control, the switching elements E3 to E8 (E9 to E14) are turned on and off once per electrical angle cycle of the motors MG1 and MG2, and one pulse per electrical angle half cycle for each phase. This is the rotation synchronization control that is output. In other words, in the rectangular wave control, the output voltage waveforms of the inverters 5 and 6 of the U, V, and W phases appear alternately in the high level period and the low level period once per cycle. Control is performed so that the ratio of the level period to the low level period is a rectangular wave of 1: 1. At this time, the output voltage waveforms of the respective phases are outputted with a phase shift of 120 °. Thus, the rectangular wave control causes the inverters 5 and 6 to output a rectangular wave voltage. In the rectangular wave control, the actual modulation rate M is fixed at “0.78” which is the maximum modulation rate Mmax. That is, when the actual modulation rate M reaches the maximum modulation rate Mmax, rectangular wave control is executed.

  The field control by the field adjustment value in the present embodiment includes normal field control and field weakening control. Here, the field control is a control for adjusting the field magnetic flux of the electric motors MG1 and MG2 by the field adjustment command value ΔId for adjusting the basic current command values Id and Iq determined by the current command determination unit 11 as described above. is there. As described above, the current command determination unit 11 determines the basic current command values Id and Iq so as to perform maximum torque control. In the normal field control, the field adjustment command value ΔId is set to zero (ΔId = 0) so as not to adjust the basic current command values Id and Iq. That is, in this embodiment, the normal field control is maximum torque control. On the other hand, field weakening control is field control that adjusts the basic current command values Id and Iq so as to weaken the field magnetic flux of the electric motors MG1 and MG2 as compared with normal field control (maximum torque control). That is, the field weakening control is a control for adjusting the current phase so that a magnetic flux in a direction of weakening the field magnetic flux of the electric motors MG1 and MG2 is generated from the armature coil. Here, in the field weakening control, the field adjustment command value ΔId is set so that the current phase is advanced as compared with the normal field control. Specifically, in the field weakening control, the field adjustment command value ΔId is set to a negative value (ΔId <0) so as to change (decrease) the basic d-axis current command value Id in the negative direction.

  Each of the plurality of control modes selected by the mode control unit 15 includes voltage waveform control such as normal PWM control, overmodulation PWM control, and rectangular wave control as described above, and field control such as normal field control and field weakening control. It is comprised by the combination of. Specifically, the normal PWM control mode C1 is a mode for executing normal PWM control together with normal field control (maximum torque control), and the first overmodulation PWM control mode C2 is for executing overmodulation PWM control together with normal field control. The second overmodulation PWM control mode C3 is a mode for executing overmodulation PWM control together with field weakening control, and the rectangular wave control mode C4 is a mode for executing rectangular wave control together with field weakening control. As shown in FIG. 5, the mode control unit 15 selects the normal PWM control mode C1 in the range where the actual modulation rate M is “0 to 0.707”, and the actual modulation rate M is “0.707 to 0.74”. The first overmodulation PWM control mode C2 is selected in the range of “”, the second overmodulation PWM control mode C3 is selected in the range where the actual modulation rate M is “0.74 to 0.78”, and the actual modulation rate M is When “0.78”, the rectangular wave control mode C4 is selected. Then, the mode control unit 15 performs control to operate the three-phase command value deriving unit 17 and the inverter control signal generating unit 18 according to the selected control mode. Note that the value of the actual modulation factor M that serves as a threshold value for switching between the control modes is merely an example, and can naturally be set to other values.

  The three-phase command value deriving unit 17 receives the d-axis voltage command value Vd and the q-axis voltage command value Vq. The three-phase command value deriving unit 17 also receives the magnetic pole positions θ (θ1, θ2) detected by the rotation sensors 65 and 66 (see FIG. 1). The three-phase command value deriving unit 17 performs two-phase / three-phase conversion on the d-axis voltage command value Vd and the q-axis voltage command value Vq using the magnetic pole position θ, thereby obtaining a three-phase AC voltage command value, that is, a U-phase. A voltage command value Vu, a V-phase voltage command value Vv, and a W-phase voltage command value Vw are derived. However, since the waveforms of these AC voltage command values Vu, Vv, and Vw are different for each control mode, the three-phase command value deriving unit 17 determines the AC voltage command values Vu, Vv, and Vw having different voltage waveforms for each control mode. Is output to the inverter control signal generator 18. Specifically, when the three-phase command value deriving unit 17 receives a normal PWM control execution command from the mode control unit 15, the AC voltage command values Vu and Vv of the AC voltage waveform corresponding to the normal PWM control. , Vw is output. Here, since the normal PWM control is SVPWM control, AC voltage command values Vu, Vv, and Vw are output according to the AC voltage waveform for the SVPWM control. Further, when the three-phase command value deriving unit 17 receives an overmodulation PWM control execution command from the mode control unit 15, the AC voltage command values Vu, Vv, Vw is output. Further, when the three-phase command value deriving unit 17 receives a rectangular wave control execution command from the mode control unit 15, the three-phase command value deriving unit 17 obtains AC voltage command values Vu, Vv, and Vw of an AC voltage waveform corresponding to the rectangular wave control. Output. Here, the AC voltage command values Vu, Vv, and Vw when executing the rectangular wave control are set as command values for the on / off switching phases of the switching elements E3 to E8 (E9 to E14) of the inverter 5 (6). it can. This command value corresponds to the on / off control signal of each of the switching elements E3 to E8 (E9 to E14), and indicates the magnetic pole position θ1 (θ2) representing the timing for switching on or off of each of the switching elements E3 to E8 (E9 to E14). Is a command value representing the phase of.

  The inverter control signal generator 18 receives the U-phase voltage command value Vu, the V-phase voltage command value Vv, and the W-phase voltage command value Vw generated by the three-phase command value deriving unit 17. The inverter control signal generation unit 18 controls the switching elements E3 to E8 (E9 to E14) of the inverter 5 (6) shown in FIG. 1 according to the AC voltage command values Vu, Vv, and Vw. S8 (S9 to S14) is generated. The inverter 5 (6) performs on / off operations of the switching elements E3 to E8 (E9 to E14) according to the inverter control signals S3 to S8 (S9 to S14). Thereby, PWM control (normal PWM control or overmodulation PWM control) or rectangular wave control of the electric motors MG1 and MG2 is performed.

1-3-2. Configuration of Voltage Conversion Command Determination Unit Next, the configuration of the voltage conversion command determination unit 8 will be described. In the present embodiment, a case will be described in which a real field adjustment value ΔIdr is used as a target field adjustment value that becomes a control variable in feedback control for determining the system voltage command value Vdct. By providing the voltage conversion command determination unit 8, the control device 1 is based on the target torque TM (TM1, TM2) and the rotational speed ω (ω1, ω2) of either the first electric motor MG1 or the second electric motor MG2. A system that is a command value of the system voltage Vdc is determined so as to determine a target field adjustment value ΔIdt that is a control target value of the real field adjustment value ΔIdr and to match the real field adjustment value ΔIdr with the target field adjustment value ΔIdt. It is characterized in that the voltage command value Vdct is determined.

  As described above, the control device 1 includes only one voltage conversion command determination unit 8 in order to perform control for causing the two inverters 5 and 6 to generate a common system voltage Vdc by one voltage conversion unit 4. . Therefore, the voltage conversion command determination unit 8 selects the inverters 5 and 6 having the larger actual modulation rate M (M1, M2) derived by the corresponding actual modulation rate deriving unit 14 among the two inverters 5 and 6. It operates as a target and determines a system voltage command value Vdct common to the two inverters 5 and 6. More specifically, the voltage conversion command determination unit 8 includes the first actual modulation rate M1 derived by the actual modulation rate deriving unit 14 of the first inverter control command determination unit 71 corresponding to the first inverter 5 and the second inverter 6. Is compared with the second actual modulation factor M2 derived by the actual modulation factor deriving unit 14 of the second inverter control command determining unit 72 corresponding to The system voltage command value Vdct is determined based on the information of 5, 6 and the motors MG1, MG2 corresponding thereto. In order to select the inverters 5 and 6, the voltage conversion command determination unit 8 includes a modulation rate comparison unit 44, a first switch 41, a second switch 42, and a third switch 43.

  The modulation factor comparison unit 44 compares the first actual modulation factor M1 derived by the first inverter control command determination unit 71 with the second actual modulation factor M2 derived by the second inverter control command determination unit 72, The first switching device 41, the second switching device 42, and the third switching device 43 are controlled so as to target the inverters 5 and 6 and the electric motors MG1 and MG2 having the larger value. The first switch 41 is output from the first actual d-axis current Idr1 and the first basic d-axis current command value Id1 output from the first inverter control command determination unit 71, and from the second inverter control command determination unit 72. Which one of the second actual d-axis current Idr2 and the second basic d-axis current command value Id2 is input to the real field adjustment value detection unit 45 is selectively switched. In other words, the first switch 41 determines that the first actual d-axis current Idr1 and the first basic d-axis current command value Id1 are in real world when the modulation factor comparison unit 44 determines that the first actual modulation factor M1 is large. When input to the magnetic adjustment value detection unit 45 and it is determined that the second actual modulation factor M2 is large, the second actual d-axis current Idr2 and the second basic d-axis current command value Id2 are used as the real field adjustment value detection unit. 45.

  Similarly, the second switch 42 includes the first target torque TM1 of the first electric motor MG1, the first rotational speed ω1 of the first electric motor MG1 output from the first inverter control command determination unit 71, and the second electric motor MG2. The second target torque TM2 and the second rotation speed ω2 of the second electric motor MG2 output from the second inverter control command determination unit 72 are selectively switched to be input to the target field adjustment value determination unit 32. . That is, the second switch 42 determines that the first target torque TM1 and the first rotation speed ω1 are the target field adjustment value determination unit 32 when the modulation factor comparison unit 44 determines that the first actual modulation factor M1 is large. When the second actual modulation factor M2 is determined to be large, the second target torque TM2 and the second rotation speed ω2 are input to the target field adjustment value determination unit 32. Further, the third switch 43 includes a first actual modulation factor M1 output from the first inverter control command determination unit 71 and a second actual modulation factor M2 output from the second inverter control command determination unit 72. Which is input to the subtractor 50 is selectively switched. That is, the third switch 43 inputs the first actual modulation rate M1 to the subtractor 50 when the modulation rate comparison unit 44 determines that the first actual modulation rate M1 is large, and the second actual modulation rate M2 Is determined to be large, the second actual modulation factor M2 is input to the subtractor 50.

Based on the actual d-axis current Idr (Idr1, Idr2) selected by the first switch 41 and the basic d-axis current command value Id (Id1, Id2), the real field adjustment value detection unit 45 The real field adjustment value ΔIdr is detected and acquired. That is, the real field adjustment value detection unit 45 selects the first inverter 5 and the first electric motor when the first actual d-axis current Idr1 and the first basic d-axis current command value Id1 are selected by the first switch 41. When the real field adjustment value ΔIdr1 of MG1 is detected and the second actual d-axis current Idr2 and the second basic d-axis current command value Id2 are selected by the first switch 41, the second inverter 6 and the second electric motor The real field adjustment value ΔIdr2 of MG2 is detected. Here, the actual d-axis current Idr is a value based on the actual current Ir (Ir1, Ir2) detected by the current sensors 63, 64 (see FIG. 1) and is actually supplied to the motors MG1, MG2. Represents the d-axis component. The basic d-axis current command value Id is a command value for the d-axis current based on normal field control before adjustment by the field adjustment command value ΔId. Accordingly, a value obtained by subtracting the basic d-axis current command value Id from the actual d-axis current Idr is an actual field adjustment value ΔIdr (ΔIdr1, ΔIdr2) which is an actual field adjustment value. Therefore, the real field adjustment value detector 45 detects and acquires the real field adjustment value ΔIdr according to the following equation (6).
ΔIdr = Idr−Id (6)
In the present embodiment, the actual field adjustment value ΔIdr acquired in this way is the target field adjustment value. Therefore, the target field adjustment value acquisition unit 31 according to the present invention is configured by the first switch 41 and the real field adjustment value detection unit 45 for acquiring the real field adjustment value ΔIdr. The actual field adjustment value ΔIdr detected in this way is a value according to the field adjustment command value ΔId determined by the field adjustment unit 12 of the inverter control command determination unit 7.

  The target field adjustment value determination unit 32 selects the actual field adjustment value ΔIdr based on the target torque TM (TM1, TM2) selected and input by the second switch 42 and the rotational speed ω (ω1, ω2). The target field adjustment value ΔIdt, which is the control target value of, is determined. That is, the target field adjustment value determination unit 32 adjusts the target field adjustment of the first inverter 5 and the first electric motor MG1 when the first target torque TM1 and the first rotation speed ω1 are selected by the second switch 42. The value ΔIdt1 is determined, and when the second target torque TM2 and the second rotation speed ω2 are selected by the second switch 42, the target field adjustment value ΔIdt2 of the second inverter 6 and the second electric motor MG2 is determined. Here, the target field adjustment value ΔIdt (ΔIdt1, ΔIdt2) is determined so as to increase as one or both of the rotational speed ω and the target torque TM of the electric motors MG1, MG2 increase. In the present embodiment, the target field adjustment value determination unit 32 determines the target field adjustment value ΔIdt based on the target field adjustment value map 46.

  FIG. 7 shows an example of the target field adjustment value map 46. The target field adjustment value map 46 defines a target field adjustment value ΔIdt associated with the target torque TM and the rotational speed ω. In this figure, the area surrounded by the solid line is the operable area of the electric motors MG1 and MG2, and the alternate long and short dash line shows the equal target field adjustment value line 104 where the target field adjustment value ΔIdt has the same value. In the example shown in FIG. 7, the target field adjustment value map 46 stipulates that the target field adjustment value ΔIdt increases as both the rotational speed ω and the target torque TM increase. As a result, the target field adjustment value ΔIdt is determined so as to gradually increase as the iron loss increases as the rotational speed increases and the output torque increases. As will be described later, the voltage conversion command determination unit 8 performs control to determine the system voltage command value Vdct so that the actual field adjustment value ΔIdr matches the target field adjustment value ΔIdt. Therefore, by determining the target field adjustment value ΔIdt as described above, the actual field adjustment value ΔIdr can be controlled to become a large value as the situation where the iron loss easily increases proceeds. . As the actual field adjustment value ΔIdr becomes larger, the field magnetic flux of the electric motors MG1 and MG2 is weakened, so that the occurrence of iron loss caused by the field magnetic flux can be suppressed. . Thereby, the efficiency of the whole system including the electric motors MG1 and MG2 and the electric motor drive device 2 can be increased.

  The voltage conversion command determination unit 8 determines a system voltage command value Vdct that is a command value of the system voltage Vdc so that the actual field adjustment value ΔIdr matches the target field adjustment value ΔIdt. Therefore, the voltage conversion command determination unit 8 includes a subtractor 47, an integrator 48, and an amplifier 49. The subtractor 47 receives the actual field adjustment value ΔIdr acquired by the actual field adjustment value detection unit 45 and the target field adjustment value ΔIdt determined by the target field adjustment value determination unit 32. The subtractor 47 derives a difference value obtained by subtracting the target field adjustment value ΔIdt from the real field adjustment value ΔIdr and outputs the difference value to the integrator 48. The integrator 48 integrates the difference value and outputs the integrated value to the amplifier 49. The amplifier 49 multiplies this integral value by a predetermined gain k. In this manner, the field adjustment voltage command value Vta is derived by the subtractor 47, the integrator 48, and the amplifier 49. This field adjustment voltage command value Vta is an adjustment command value of the system voltage Vdc for making the actual field adjustment value ΔIdr coincide with the target field adjustment value ΔIdt. The derived field adjustment voltage command value Vta is output to the adder 52. Here, when the actual field adjustment value ΔIdr is larger than the target field adjustment value ΔIdt, a positive field adjustment voltage command value Vta is output, which acts to increase (boost) the system voltage command value Vdct. . On the other hand, when the actual field adjustment value ΔIdr is smaller than the target field adjustment value ΔIdt, a negative field adjustment voltage command value Vta is output, which acts in the direction of lowering (decreasing) the system voltage command value Vdct.

  The voltage conversion command determination unit 8 also determines the system voltage command value Vdct so that the actual modulation factor M matches the target modulation factor MT. For this reason, the voltage conversion command determination unit 8 includes a subtractor 50 and an amplifier 51. The actual modulation rate M (M1, M2) selected and input by the third switch 43 and the target modulation rate MT are input to the subtracter 50. As described above, in the present embodiment, the voltage conversion command determination unit 8 uses the same target modulation rate MT that is used in the inverter control command determination unit 7 to derive the modulation rate deviation ΔM. That is, the target modulation factor MT is the theoretical maximum modulation factor Mmax (= 0.78) that can be realized in the system including the electric motors MG1, MG2 and the electric motor drive device 2, in other words, starts (executes) the rectangular wave control mode C4. Is set to the value of the actual modulation factor M, which is a condition for The subtracter 50 derives a difference value obtained by subtracting the actual modulation rate M from the target modulation rate MT, and outputs the difference value to the amplifier 51. The amplifier 51 multiplies this difference value by a predetermined gain j. In this way, the modulation factor adjusting voltage command value Vtb is derived by the subtractor 50 and the amplifier 51. This modulation factor adjustment voltage command value Vtb is an adjustment command value of the system voltage Vdc for making the actual modulation factor M coincide with the target modulation factor MT. The derived modulation rate adjustment voltage command value Vtb is output to the adder 52. Here, when the actual modulation rate M is larger than the target modulation rate MT, a positive modulation rate adjustment voltage command value Vtb is output, which acts to increase (boost) the system voltage command value Vdct. On the other hand, when the actual modulation rate M is smaller than the target modulation rate MT, a negative modulation rate adjustment voltage command value Vtb is output, which acts in the direction of lowering (decreasing) the system voltage command value Vdct.

The adder 52 derives a value obtained by adding the field adjustment voltage command value Vta and the modulation factor adjustment voltage command value Vtb, and outputs the value to the system voltage determination unit 33. Therefore, the addition value of the field adjustment voltage command value Vta and the modulation factor adjustment voltage command value Vtb is input to the system voltage determination unit 33. The system voltage determination unit 33 holds the previously determined system voltage command value Vdct (O). Then, as shown in the following equation (7), the system voltage determination unit 33 uses the field adjustment voltage command value Vta and the modulation factor adjustment voltage command for the previously determined system voltage command value Vdct (O). The next system voltage command value Vdct (N) is determined by adding the value added to the value Vtb.
Vdct (N) = Vdct (O) + Vta + Vtb (7)
Thus, system voltage determination unit 33 determines system voltage command value Vdct so that actual field adjustment value ΔIdr matches target field adjustment value ΔIdt and actual modulation factor M matches target modulation factor MT. be able to.

  The system voltage command value Vdct determined by the system voltage determination unit 33 is input to the voltage conversion control unit 53. Further, the voltage conversion control unit 53 also receives the power supply voltage Vb detected by the power supply voltage sensor 61. The voltage conversion control unit 53 performs the operation of converting the power supply voltage Vb into the system voltage command value Vdct in accordance with the input system voltage command value Vdct. Voltage conversion control signals S1 and S2 for controlling the conversion switching elements E1 and E2 are generated. The voltage conversion unit 4 performs on / off operations of the voltage conversion switching elements E1 and E2 in accordance with the voltage conversion control signals S1 and S2. As a result, the power supply voltage Vb is converted to generate a system voltage Vdc according to the system voltage command value Vdct, which is supplied to the first inverter 5 and the second inverter 6.

  The system voltage command value Vdct determined by the system voltage determination unit 33 as described above is used to set the basic current command values Id and Iq to the target values by feedback control in which the actual field adjustment value ΔIdr matches the target field adjustment value ΔIdt. The adjusted current command value adjusted by the field adjustment value ΔIdt is determined to be a value on the voltage limit ellipse 103. This point will be described with reference to FIG. FIG. 8 is a current command value map similar to FIG. 6, but a thick broken line in the figure indicates a target field adjustment value line indicating a target field adjustment value ΔIdt that gradually increases as the target torque TM increases. 105.

  If the control device 1 does not include the voltage conversion command determination unit 8 which is a feature of the present invention, as shown in FIG. 6, for example, when a value of “TM-5” is input as the target torque TM, the inverter The control command determination unit 7 determines the d-axis and q-axis values (Id3, Iq3) on the voltage limiting ellipse 103 at that time as the adjusted current command values Ida, Iqa. Since the magnitude of the field adjustment command value ΔId at this time does not take into account the target field adjustment value ΔIdt, the actual field adjustment value ΔIdr is not an appropriate value.

  On the other hand, according to the configuration of the present embodiment, since the control device 1 includes the voltage conversion command determination unit 8, the actual field adjustment value ΔIdr matches the target field adjustment value ΔIdt by feedback control. The system voltage command value Vdct is determined. At this time, the size of the voltage limiting ellipse 103 changes depending on the system voltage Vdc. Further, the field adjustment command value ΔId that becomes the command value of the actual field adjustment value ΔIdr is the current adjustment values Ida and Iqa after the adjustment based on the field adjustment command value ΔId as described above. To be determined. Therefore, as indicated by the white arrow 106 in FIG. 8, the voltage limit ellipse 103 is large so that the actual field adjustment value ΔIdr matches the target field adjustment value ΔIdt by adjusting the system voltage command value Vdct. Is adjusted. For example, when a value of “TM-5” is input as the target torque TM, the adjusted current command values Ida and Iqa based on the field adjustment command value ΔId (Id6, Iq6) are the basic current command values Id, Iq. (Id2, Iq2) is equal to the adjusted current command value adjusted by the target field adjustment value ΔIdt. That is, the system voltage command value Vdct is determined so that the adjusted current command value obtained by adjusting the basic current command values Id and Iq with the target field adjustment value ΔIdt becomes a value on the voltage limit ellipse 103. Thus, the actual field adjustment value ΔIdr can be adjusted to an appropriate value according to the operating state of the electric motors MG1 and MG2, and the efficiency of the entire system including the electric motors MG1 and MG2 and the electric motor drive device 2 is increased. It is possible. In the state where the system voltage command value Vdct is larger than the power supply voltage Vb, the voltage is limited so that the actual field adjustment value ΔIdr coincides with the target field adjustment value ΔIdt by adjusting the system voltage command value Vdct to be lowered. It is also possible to adjust the size of the ellipse 103 in the reduction direction.

  In the present embodiment, since the voltage conversion unit 4 performs only boosting, the lower limit of the system voltage command value Vdct is the power supply voltage Vb. Therefore, in the state where the system voltage command value Vdct matches the power supply voltage Vb, the system voltage command value Vdct is further lowered even if the actual field adjustment value ΔIdr is made to match the target field adjustment value ΔIdt. I can't. Further, the range that can be boosted by the voltage conversion unit 4 is determined in advance, and there is a boost upper limit Vmax (see FIG. 9). Therefore, the system voltage determination unit 33 determines the system voltage command value Vdct so that the actual field adjustment value ΔIdr matches the target field adjustment value ΔIdt. The system voltage command value Vdct is equal to or higher than the power supply voltage Vb. It is performed within a range of Vmax or less (Vb ≦ Vdct ≦ Vmax). In the present embodiment, the boost upper limit Vmax is set to “n · Vb”. For example, when the power supply voltage Vb is “200 [V]” and the maximum boost ratio n is “2”, the boost upper limit Vmax is “400 [V]”.

1-4. Operation of Control Device Next, an example of the operation of the control device 1 that controls the electric motor drive device 2 will be described with reference to the time chart shown in FIG. This time chart is for one set of the two electric motors MG1, MG2 and the inverters 5 and 6, in this example, the first electric motor MG1 and the first inverter 5, and rotates with the target torque TM held constant. It represents the operating state of the control device 1 when the speed ω is gradually increased.

  In the example of FIG. 9, the rotational speed ω gradually increases at a constant acceleration after time T1. As the rotational speed ω increases in this way, the induced voltage and the armature reaction in the electric motor MG1 increase, and the AC voltage command values Vd and Vq gradually increase. Therefore, the actual modulation factor M also gradually increases after time T1. To do. The actual modulation rate M becomes “0.707” at time T2, reaches “0.74” at time T3, and reaches “0.78”, which is the maximum modulation rate Mmax, at time T4. At this time, before the time point T1 and before the time points T1 to T2, the actual modulation rate M is “0.707” or less, so the control device 1 executes the normal PWM control mode C1. At time points T2 to T3 when the actual modulation factor M falls within the range of “0.707 to 0.74”, the control device 1 executes the first overmodulation PWM control mode C2, and the actual modulation factor M is “0.74”. At time points T3 to T4 that fall within the range of “˜0.78”, the control device 1 executes the second overmodulation PWM control mode C3. Then, after time T4 after the actual modulation rate M becomes “0.78”, which is the maximum modulation rate Mmax, the control device 1 executes the rectangular wave control mode C4.

  During this time, the target field adjustment value ΔIdt determined by the target field adjustment value determination unit 32 gradually increases as the rotational speed ω increases. On the other hand, the actual field adjustment value ΔIdr changes according to the field adjustment command value ΔId, and the field adjustment command value ΔId is determined by the field modulation unit 12 of the inverter control command determination unit 7 and the actual modulation rate M. It is determined according to the modulation factor deviation ΔM which is the difference from the modulation factor MT (see FIG. 3). Specifically, as described above, when the modulation rate deviation ΔM is equal to or less than the field weakening start threshold value ΔMs, the field adjustment command value ΔId is set to zero, and the modulation rate deviation ΔM is set to the field weakening start threshold value. The field adjustment command value ΔId gradually increases from when it becomes larger than ΔMs. In this embodiment, since the field weakening start threshold value ΔMs is set to “−0.04”, the field adjustment command is set after time T3 when the actual modulation rate M becomes larger than “Mmax + ΔMs = 0.74”. The value ΔId gradually increases. Along with this, the actual field adjustment value ΔIdr also gradually increases. The field weakening control is started when the actual field adjustment value ΔIdr is greater than zero, and the control mode shifts from the first overmodulation PWM control mode C2 to the second overmodulation PWM control mode C3.

  At time T4, the actual modulation rate M becomes “0.78”, which is the maximum modulation rate Mmax, and the real field adjustment value ΔIdr increases as the rotational speed ω increases even after the rectangular wave control mode C4 is started. At time T5, the actual field adjustment value ΔIdr matches the target field adjustment value ΔIdt. After time T5, in order to suppress the increase in the real field adjustment value ΔIdr and keep the state matching the target field adjustment value ΔIdt, the voltage conversion command determination unit 8 uses the real field adjustment value ΔIdr and the target field adjustment value. A field adjustment voltage command value Vta is derived based on ΔIdt, and a system voltage command value Vdct is determined based on the field adjustment voltage command value Vta (see FIG. 4). Thus, system voltage command value Vdct gradually increases from power supply voltage Vb as rotation speed ω and target field adjustment value ΔIdt increase. By adjusting the system voltage command value Vdct in this way, as described above, the state where the actual field adjustment value ΔIdr matches the target field adjustment value ΔIdt is maintained. After that, after the system voltage command value Vdct reaches the boost upper limit Vmax at time T6, the system voltage command value Vdct cannot be increased any further, so the actual field adjustment value ΔIdr exceeds the target field adjustment value ΔIdt. Rise.

  By the way, before the time T5, since the actual field adjustment value ΔIdr is smaller than the target field adjustment value ΔIdt, the field adjustment voltage command value Vta derived by the voltage conversion command determination unit 8 becomes a negative value, and the system voltage It acts in the direction of lowering (decreasing) the command value Vdct. However, in the present embodiment, the voltage conversion unit 4 performs only boosting and does not lower the voltage. Therefore, in the state where the system voltage command value Vdct matches the power supply voltage Vb and is not boosted, such negative field adjustment is performed. Depending on the voltage command value Vta, the system voltage command value Vdct does not change and is maintained constant (power supply voltage Vb). On the other hand, after time T5, the actual field adjustment value ΔIdr tends to be larger than the target field adjustment value ΔIdt, so that the field adjustment voltage command value Vta becomes a positive value, and the system voltage command value Vdct is increased (boosted). ) Acts in the direction of. As a result, the system voltage command value Vdct increases. After the system voltage command value Vdct becomes larger than the power supply voltage Vb, both the positive and negative field adjustment voltage command values Vta function to make the actual field adjustment value ΔIdr coincide with the target field adjustment value ΔIdt. Thus, the system voltage command value Vdct can be increased or decreased.

  Prior to time T4, since the actual modulation factor M is smaller than the target modulation factor MT, the modulation factor adjustment voltage command value Vtb derived in the voltage conversion command determination unit 8 is a negative value, and the system voltage command value Vdct is It acts in the direction of descending (decreasing pressure). However, in the present embodiment, the voltage conversion unit 4 performs only boosting and does not step down. Therefore, in the state where the system voltage command value Vdct matches the power supply voltage Vb and is not boosted, such negative modulation rate adjustment is performed. Depending on the voltage command value Vtb, the system voltage command value Vdct does not change and is maintained constant (power supply voltage Vb). On the other hand, after time T4, the inverter control command determination unit 7 performs control to maintain the actual modulation rate M at the target modulation rate MT (= 0.78), and therefore the modulation rate adjustment voltage command value Vtb is zero (Vtb = 0) and does not act on the system voltage command value Vdct. After the time point T5, after the system voltage command value Vdct becomes larger than the power supply voltage Vb, the negative modulation factor adjustment voltage command value Vtb functions to make the actual modulation factor M coincide with the target modulation factor MT. The system voltage command value Vdct can be adjusted.

  In the present embodiment, as described above, the target field adjustment value ΔIdt is determined so as to increase as both the rotational speed ω and the target torque TM increase. Therefore, even when the target torque TM is gradually increased while the rotational speed ω is kept constant, or even when both the rotational speed ω and the target torque TM are gradually increased, the operation of the control device 1 is as follows. This is almost the same as described above.

2. Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIGS. 10 and 11. The present embodiment is different from the first embodiment in that the voltage converter 4 is a step-up / down converter that not only boosts the power supply voltage Vb but also steps down the voltage. Due to the difference in the configuration of the voltage conversion unit 4, the operation of the control device 1 is also different from that in the first embodiment. Below, the control apparatus 1 which concerns on this embodiment is demonstrated centering around difference with said 1st embodiment. Note that points not particularly described are the same as those in the first embodiment.

2-1. Method for Determining System Voltage Command Value First, a method for determining the system voltage command value Vdct in this embodiment will be described. The configuration of the voltage conversion command determination unit 8 provided in the control device 1 and the processing inside thereof are the same as those in the first embodiment. However, in this embodiment, since the voltage conversion unit 4 performs both boosting and stepping down, the lower limit of the system voltage command value Vdct is set to a value smaller than the power supply voltage Vb. That is, the system voltage command value Vdct for controlling the voltage conversion unit 4 can be changed between the step-down lower limit Vmin (<Vb) and the step-up upper limit Vmax (> Vb). Therefore, the system voltage determining unit 33 determines the system voltage command value Vdct so that the actual field adjustment value ΔIdr matches the target field adjustment value ΔIdt. The system voltage command value Vdct is greater than or equal to the step-down lower limit Vmin. It is performed within a range of Vmax or less (Vmin ≦ Vdct ≦ Vmax). In this embodiment, the step-down lower limit Vmin is set to “(1 / n) Vb”, and the step-up upper limit Vmax is set to “n · Vb”. For example, when the power supply voltage Vb is “200 [V]” and the maximum step-up / step-down ratio n is “2”, the step-down lower limit Vmin is “100 [V]” and the step-up upper limit Vmax is “400 [V]”.

  As in the first embodiment, the system voltage command value Vdct determined by the system voltage determination unit 33 is obtained by performing feedback control that matches the actual field adjustment value ΔIdr with the target field adjustment value ΔIdt. The adjusted current command value obtained by adjusting the command values Id and Iq with the target field adjustment value ΔIdt is determined to be a value on the voltage limit ellipse 103. This point will be described with reference to FIG. FIG. 10 is a view similar to FIG. 8 according to the first embodiment.

  In the configuration of the first embodiment in which the voltage conversion unit 4 only boosts and does not step down, for example, when a value of “TM-3” is input as the target torque TM, the inverter control command determination unit 7 sets the target torque. (Id7, Iq7), which is the intersection of the equal torque line 101 of TM = TM-3 and the maximum torque control line 102, is determined as the basic current command values Id, Iq. This (Id7, Iq7) is inside the voltage limiting ellipse 103, and since the diameter of the voltage limiting ellipse 103 cannot be reduced by lowering (decreasing) the system voltage Vdc, field weakening control is not performed and the field The adjustment command value ΔId is zero (ΔId = 0). Accordingly, the actual field adjustment value ΔIdr that changes in accordance with the field adjustment command value ΔId is also zero (ΔIdr = 0), and cannot match the target field adjustment value ΔIdt represented by the target field adjustment value line 105.

  On the other hand, according to the configuration of the present embodiment, since the voltage conversion unit 4 can perform both step-up and step-down, when the basic current command values Id and Iq are inside the voltage limit ellipse 103, By decreasing (decreasing) the system voltage Vdc, the diameter of the voltage limiting ellipse 103 can be reduced, and the field adjustment command value ΔId can be set to a negative value (ΔId <0). Here, the size of the voltage limiting ellipse 103 changes depending on the system voltage Vdc. Further, the field adjustment command value ΔId that becomes the command value of the actual field adjustment value ΔIdr is the current adjustment values Ida and Iqa after the adjustment based on the field adjustment command value ΔId as described above. To be determined. For this reason, as shown by the white arrow 107 in FIG. 10, by adjusting the system voltage command value Vdct in the decreasing direction, the voltage limit ellipse is set so that the actual field adjustment value ΔIdr matches the target field adjustment value ΔIdt. The size of 103 can be adjusted in the reduction direction. Thereby, for example, when a value of “TM-3” is input as the target torque TM, the adjusted current command values Ida and Iqa (Id8, Iq8) based on the field adjustment command value ΔId are the basic current command values. Id and Iq (Id7, Iq7) coincide with the adjusted current command value adjusted by the target field adjustment value ΔIdt. That is, the system voltage command value Vdct is determined so that the adjusted current command value obtained by adjusting the basic current command values Id and Iq with the target field adjustment value ΔIdt becomes a value on the voltage limit ellipse 103. Therefore, even when the target torque TM and the rotational speed ω of the electric motors MG1 and MG2 are low, the actual field adjustment value ΔIdr can be adjusted to an appropriate value according to the operating state of the electric motors MG1 and MG2. It is possible to increase the efficiency of the entire system including MG1, MG2 and the electric motor drive device 2. As in the first embodiment, the actual field adjustment value ΔIdr matches the target field adjustment value ΔIdt by adjusting the system voltage command value Vdct so as to increase as indicated by the white arrow 106. Of course, it is also possible to adjust the size of the voltage limiting ellipse 103 in the enlargement direction.

2-2. Operation of Control Device Next, an example of the operation of the control device 1 that controls the electric motor drive device 2 will be described with reference to a time chart shown in FIG. This time chart shows one set of two electric motors MG1, MG2 and inverters 5, 6 as in FIG. 9 according to the first embodiment, in this example, the first electric motor MG1 and the first inverter 5. This shows the operating state of the control device 1 when the rotational speed ω is gradually increased while the target torque TM is kept constant.

  In the example of FIG. 11, the rotational speed ω gradually increases at a constant acceleration after time T1. On the other hand, at the time T1, the actual modulation rate M is a value that is significantly smaller than the maximum modulation rate Mmax (= 0.78), which is the target modulation rate MT. A small state continues with respect to the target modulation rate MT. Therefore, the modulation factor adjustment voltage command value Vtb derived in the voltage conversion command determination unit 8 becomes a negative value, and acts in the direction of lowering (decreasing) the system voltage command value Vdct. Further, at time T1, the real field adjustment value ΔIdr is zero, which is significantly smaller than the target field adjustment value ΔIdt, and thereafter, the real field adjustment value ΔIdr remains at the target field until time T5. A small state continues with respect to the magnetic adjustment value ΔIdt. Therefore, the field adjustment voltage command value Vta derived in the voltage conversion command determination unit 8 is a negative value, and acts in the direction of lowering (decreasing) the system voltage command value Vdct. Therefore, at time points T1 to T5, the system voltage command value Vdct decreases due to the negative modulation factor adjustment voltage command value Vtb and the field adjustment voltage command value Vta. The actual modulation rate M increases faster than the case shown in FIG. 9 due to the increase in the rotational speed ω and the decrease in the system voltage Vdc corresponding to the decrease in the system voltage command value Vdct. The actual modulation rate M becomes “0.707” at time T2, reaches “0.74” at time T3, and reaches “0.78”, which is the maximum modulation rate Mmax, at time T4. At this time, before the time point T1 and before the time points T1 to T2, the actual modulation rate M is “0.707” or less, so the control device 1 executes the normal PWM control mode C1. At time points T2 to T3 when the actual modulation factor M falls within the range of “0.707 to 0.74”, the control device 1 executes the first overmodulation PWM control mode C2, and the actual modulation factor M is “0.74”. At time points T3 to T4 that fall within the range of “˜0.78”, the control device 1 executes the second overmodulation PWM control mode C3. Then, after time T4 after the actual modulation rate M becomes “0.78”, which is the maximum modulation rate Mmax, the control device 1 executes the rectangular wave control mode C4.

  During this time, the target field adjustment value ΔIdt determined by the target field adjustment value determination unit 32 gradually increases as the rotational speed ω increases. On the other hand, the actual field adjustment value ΔIdr changes according to the field adjustment command value ΔId, and the field adjustment command value ΔId has an actual modulation factor M of “Mmax + ΔMs = 0. If it is less than 74 ”, the field adjustment command value ΔId is set to zero, and the field adjustment command value ΔId increases after time T3 when the actual modulation factor M becomes greater than“ 0.74 ”. Along with this, the actual field adjustment value ΔIdr also increases. At this time, the actual field adjustment value ΔIdr also rises faster than in the case shown in FIG. 9 due to both the increase in the rotational speed ω and the decrease in the system voltage Vdc. The field weakening control is started when the actual field adjustment value ΔIdr is greater than zero, and the control mode shifts from the first overmodulation PWM control mode C2 to the second overmodulation PWM control mode C3.

  After the actual modulation rate M becomes “0.78” which is the maximum modulation rate Mmax at time T4, the inverter control command determination unit 7 maintains the actual modulation rate M at the target modulation rate MT (= 0.78). Since the control is performed, the modulation factor adjusting voltage command value Vtb is basically zero (Vtb = 0) and does not act on the system voltage command value Vdct. On the other hand, even after the rectangular wave control mode C4 is started at time T4, the real field adjustment value ΔIdr increases due to both the increase in the rotational speed ω and the decrease in the system voltage Vdc, and the real field adjustment is performed at time T5. The value ΔIdr matches the target field adjustment value ΔIdt. After time T5, the voltage conversion command determination unit 8 is used for positive field adjustment in order to suppress the increase in the real field adjustment value ΔIdr accompanying the increase in the rotational speed ω and keep the state matching the target field adjustment value ΔIdt. The voltage command value Vta is derived, and the field adjustment voltage command value Vta acts in the direction of increasing the system voltage command value Vdct. As a result, the system voltage command value Vdct gradually increases as the rotational speed ω and the target field adjustment value ΔIdt increase. By adjusting the system voltage command value Vdct in this way, as described above, the state where the actual field adjustment value ΔIdr matches the target field adjustment value ΔIdt is maintained. In this state, both positive and negative field adjustment voltage command values Vta function, and the system voltage command value Vdct can be raised or lowered so that the actual field adjustment value ΔIdr always matches the target field adjustment value ΔIdt. Become. After that, after the system voltage command value Vdct reaches the boost upper limit Vmax at time T6, the system voltage command value Vdct cannot be increased any further, so the actual field adjustment value ΔIdr exceeds the target field adjustment value ΔIdt. Rise.

  In this embodiment as well, as in the first embodiment, the target field adjustment value ΔIdt is determined so as to increase as both the rotational speed ω and the target torque TM increase. Therefore, even when the target torque TM is gradually increased while the rotational speed ω is kept constant, or even when both the rotational speed ω and the target torque TM are gradually increased, the operation of the control device 1 is as follows. This is almost the same as described above.

3. Third Embodiment Next, a third embodiment of the present invention will be described with reference to FIGS. In the present embodiment, as in the second embodiment, the voltage converter 4 is a step-up / down converter that not only boosts the power supply voltage Vb but also steps it down. On the other hand, the control device 1 according to the present embodiment actively starts field-weakening control during execution of the PWM control mode CP, particularly the normal PWM control mode C1, and shifts to the second PWM control mode C5. This is different from the first and second embodiments in that the value ΔIdr can be matched with the target field adjustment value ΔIdt. For this reason, in the control device 1 according to the present embodiment, the configuration of the portion for determining the target modulation factor MT in the voltage conversion command determination unit 8 and the inverter control command determination unit 7 (71, 72) is the first and second. This is different from the embodiment. Here, the second PWM control mode C5 is a mode in which normal PWM control is executed together with field weakening control. Below, the control apparatus 1 which concerns on this embodiment is demonstrated centering around difference with said 2nd embodiment. Note that points that are not particularly described are the same as in the second embodiment.

3-1. Configuration of Control Device 1 First, the configuration of the control device 1 in the present embodiment will be described. In this embodiment, the voltage conversion command determination unit 8 includes a target modulation factor determination unit 56 in addition to the same configuration as in the first and second embodiments. The target modulation factor determination unit 56 receives the actual modulation factor M (M1, M2) selected and input by the third switch 43 and the system voltage command value Vdct determined by the system voltage determination unit 33. Is done. The target modulation factor determination unit 56 determines the target modulation factor MT based on the actual modulation factor M and the system voltage command value Vdct. Here, the target modulation rate MT is an actual modulation rate that is a condition for executing the PWM control mode CP (C1 to C3) in a state where the system voltage Vdc is less than the boost upper limit Vmax that is the upper limit value of the system voltage command value Vdct. A constant intermediate target value MM set within the range of M is set, and in a state where the system voltage Vdc is the boost upper limit Vmax, the value is equal to the actual modulation factor M. In the present embodiment, the intermediate target value MM is set to “0.707”, which is the upper limit actual modulation rate M at which the normal PWM control mode C1 is executed. The intermediate target value MM is within the range of the actual modulation rate M which is a condition for executing the PWM control mode CP (C1 to C3 and C5), that is, greater than “0” and the maximum modulation rate Mmax “0.78”. An arbitrary value within the range of “<” can be set.

  The target modulation factor determination process in the target modulation factor determination unit 56 will be described with reference to the flowchart of FIG. As shown in this figure, the target modulation factor determination unit 56 first determines whether or not the system voltage command value Vdct, which is the command value of the system voltage Vdc, is the boost upper limit Vmax (step # 01). When the system voltage command value Vdct does not reach the boost upper limit Vmax (step # 01: No), the target modulation factor determination unit 56 sets the target modulation factor MT to “0.707”, which is the intermediate target value MM. (Step # 02). On the other hand, if the system voltage command value Vdct has reached the boost upper limit Vmax (step # 01: Yes), it is next determined whether or not the actual modulation factor M is greater than the intermediate target value MM (step # 03). ). When the actual modulation rate M is equal to or less than the intermediate target value MM (step # 03: No), the target modulation rate determination unit 56 determines the target modulation rate MT to be “0.707” that is the intermediate target value MM. (Step # 02). When the actual modulation factor M is larger than the intermediate target value MM (step # 03: Yes), the target modulation factor determination unit 56 makes the target modulation factor MT coincide with the actual modulation factor M. This actual modulation factor M is a value input to the target modulation factor determination unit 56 via the third switch 43. When the target modulation rate MT is matched with the actual modulation rate M in this way, the modulation rate adjustment voltage command value Vtb becomes zero, so that the voltage conversion command determination unit 8 substantially sets the actual modulation rate M to the target modulation rate. The process of determining the system voltage command value Vdct so as to coincide with the rate MT is stopped.

  Although not shown, in the present embodiment, the two inverter control command determination units 71 and 72 also include a target modulation factor determination unit similar to the voltage conversion command determination unit 8. The actual modulation factor M and the system voltage command value Vdct are also input to this target modulation factor determination unit. The target modulation factor determination unit determines the target modulation factor MT based on the actual modulation factor M and the system voltage command value Vdct. However, the target modulation factor MT used in the inverter control command determination unit 7 is the above-described intermediate target value MM (= 0.707) when the system voltage Vdc is less than the boost upper limit Vmax that is the upper limit value of the system voltage command value Vdct. When the system voltage Vdc is the boost upper limit Vmax, the maximum modulation rate Mmax (= 0.78) is set. That is, it is the same as the above-described voltage conversion command determination unit 8 except that the target modulation rate MT in a state where the system voltage Vdc is the boost upper limit Vmax is different. Therefore, the determination process of the target modulation rate MT of the inverter control command determination unit 7 is performed except that step # 04 in the flowchart shown in FIG. 13 becomes “target modulation rate MT = maximum modulation rate Mmax = 0.78”. It is the same.

3-2. Next, a method for determining the system voltage command value Vdct in this embodiment will be described. In the present embodiment, during execution of the PWM control mode CP, in particular, the normal PWM control mode C1, the field weakening control is started to shift to the second PWM control mode C5, and the actual field adjustment value ΔIdr is set to the target field adjustment value. Processing for determining the system voltage command value Vdct so as to coincide with ΔIdt is performed. Therefore, as described above, the voltage conversion command determination unit 8 sets the target modulation rate MT to “0.707”, which is the intermediate target value MM, until the system voltage command value Vdct reaches the boost upper limit Vmax. The modulation rate adjustment voltage command value Vtb is derived so that the modulation rate M matches the intermediate target value MM (target modulation rate MT). At this time, the target modulation rate MT used in the inverter control command determination unit 7 is also set to “0.707” which is also the intermediate target value MM, and the actual modulation rate M is basically set to the intermediate target value MM (target modulation value MM). The field adjustment command value ΔId is derived so as to coincide with the rate MT). Therefore, as shown in FIG. 14, until the system voltage command value Vdct reaches the boost upper limit Vmax, the voltage limit ellipse that is the outer edge of the adjustable output range of the current command values Ida and Iqa is the intermediate target value MM. An intermediate voltage limiting ellipse 108 corresponding to a certain “0.707” is obtained. In the state where system voltage command value Vdct reaches boost upper limit Vmax, target modulation factor MT used in inverter control command determination unit 7 is set to “0.78” which is maximum modulation factor Mmax. The voltage limit ellipse is the voltage limit ellipse 103 corresponding to “0.78” which is the maximum modulation rate Mmax, as in the first and second embodiments. In the following description, this voltage limit ellipse 103 is referred to as a final voltage limit ellipse for differentiation from the intermediate voltage limit ellipse 108.

  On the other hand, in this embodiment as well, as in the first and second embodiments, the system voltage command value Vdct determined by the system voltage determination unit 33 changes the actual field adjustment value ΔIdr to the target field adjustment value ΔIdt. By the feedback control for matching, the adjusted current command value obtained by adjusting the basic current command values Id and Iq by the target field adjustment value ΔIdt is the Has been determined to be. Since the determination method of the system voltage command value Vdct when the final voltage limit ellipse 103 is applied is the same as that in the second embodiment, FIG. 14 is shown here when the intermediate voltage limit ellipse 108 is applied. It explains using.

  Even in the configuration of the present embodiment, since the voltage conversion unit 4 can perform both step-up and step-down, when the basic current command values Id and Iq are inside the intermediate voltage limit ellipse 108, the system voltage Vdc is lowered. By stepping down, the diameter of the intermediate voltage limiting ellipse 108 can be reduced and the field adjustment command value ΔId can be set to a negative value (ΔId <0). Here, the size of the intermediate voltage limiting ellipse 108 varies depending on the system voltage Vdc. In addition, the field adjustment command value ΔId that becomes the command value of the actual field adjustment value ΔIdr is the value on the intermediate voltage limiting ellipse 108 after the adjusted current command values Ida and Iqa based on the field adjustment command value ΔId as described above. To be determined. Therefore, as shown by the white arrow 109 in FIG. 14, by adjusting the system voltage command value Vdct to decrease, the intermediate voltage limit is set so that the actual field adjustment value ΔIdr matches the target field adjustment value ΔIdt. The size of the ellipse 108 can be adjusted in the reduction direction. Thereby, the system voltage command value Vdct is determined such that the adjusted current command value obtained by adjusting the basic current command values Id and Iq by the target field adjustment value ΔIdt becomes a value on the intermediate voltage limit ellipse 108. . Further, as indicated by the white arrow 110, by adjusting the system voltage command value Vdct to increase, the size of the intermediate voltage limiting ellipse 108 is adjusted so that the actual field adjustment value ΔIdr matches the target field adjustment value ΔIdt. It is of course possible to adjust the height in the enlargement direction.

3-3. Operation of Control Device Next, an example of the operation of the control device 1 that controls the electric motor drive device 2 will be described with reference to the time chart shown in FIG. This time chart shows one set of two electric motors MG1, MG2 and inverters 5, 6 as in FIG. 11 according to the second embodiment, in this example, the first electric motor MG1 and the first inverter 5 This shows the operating state of the control device 1 when the rotational speed ω is gradually increased while the target torque TM is kept constant.

  In the example of FIG. 15, the rotational speed ω gradually increases at a constant acceleration after time T1. On the other hand, at the time point T1, the actual modulation rate M is a value that is significantly smaller than the intermediate target value MM (= 0.707) that is the target modulation rate MT. Therefore, the modulation factor adjustment voltage command value Vtb derived in the voltage conversion command determination unit 8 becomes a negative value, and acts in the direction of lowering (decreasing) the system voltage command value Vdct. Further, at time T1, the real field adjustment value ΔIdr is zero, which is significantly smaller than the target field adjustment value ΔIdt, and thereafter, until the time T2, the real field adjustment value ΔIdr remains at the target field. A small state continues with respect to the magnetic adjustment value ΔIdt. Therefore, the field adjustment voltage command value Vta derived in the voltage conversion command determination unit 8 is a negative value, and acts in the direction of lowering (decreasing) the system voltage command value Vdct. Therefore, at time T1 to T2, the system voltage command value Vdct decreases due to the negative modulation factor adjustment voltage command value Vtb and the field adjustment voltage command value Vta. The actual modulation factor M increases due to the decrease in the system voltage Vdc and the increase in the rotational speed ω according to the decrease in the system voltage command value Vdct. Then, actual modulation factor M reaches intermediate target value MM (= 0.707), which is target modulation factor MT when system voltage command value Vdct is lower than boost upper limit Vmax at time T2.

  During this time, the target field adjustment value ΔIdt determined by the target field adjustment value determination unit 32 gradually increases as the rotational speed ω increases. On the other hand, the actual field adjustment value ΔIdr changes according to the field adjustment command value ΔId, and the field adjustment command value ΔId is determined by the field modulation unit 12 of the inverter control command determination unit 7 and the actual modulation rate M. It is determined according to the modulation factor deviation ΔM which is the difference from the intermediate target value MM (= 0.707) which is the modulation factor MT. Specifically, as described above, when the modulation rate deviation ΔM is equal to or less than the field weakening start threshold value ΔMs, the field adjustment command value ΔId is set to zero, and the modulation rate deviation ΔM is set to the field weakening start threshold value. The field adjustment command value ΔId gradually increases from when it becomes larger than ΔMs. In this embodiment, since the field weakening start threshold value ΔMs is set to “−0.04”, the field adjustment command is executed after the actual modulation rate M becomes larger than “MM + ΔMs = 0.667”. The value ΔId gradually increases. Along with this, the actual field adjustment value ΔIdr also gradually increases. In the example of FIG. 15, the real field adjustment value ΔIdr increases from time T1. At this time, the actual field adjustment value ΔIdr rises relatively quickly due to both the lowering of the system voltage Vdc and the increase of the rotational speed ω. The field weakening control starts when the actual field adjustment value ΔIdr is greater than zero, and the control mode shifts from the normal PWM control mode C1 to the second PWM control mode C5.

  After the actual modulation rate M becomes the intermediate target value MM (= 0.707), which is the target modulation rate MT, at time T2, the inverter control command determination unit 7 sets the actual modulation rate M as the target target modulation rate MT. Since control to maintain the value MM (= 0.707) is performed, the modulation factor adjustment voltage command value Vtb is basically zero (Vtb = 0), and does not act on the system voltage command value Vdct. On the other hand, the actual field adjustment value ΔIdr coincides with the target field adjustment value ΔIdt at time T2. After time T2, in order to suppress the increase of the real field adjustment value ΔIdr accompanying the increase in the rotational speed ω and keep the state coincident with the target field adjustment value ΔIdt, the voltage conversion command determination unit 8 performs positive field adjustment. The voltage command value Vta is derived, and the field adjustment voltage command value Vta acts in the direction of increasing the system voltage command value Vdct. As a result, the system voltage command value Vdct gradually increases as the rotational speed ω and the target field adjustment value ΔIdt increase. By adjusting the system voltage command value Vdct in this way, as described above, the state where the actual field adjustment value ΔIdr matches the target field adjustment value ΔIdt is maintained. In this state, both positive and negative field adjustment voltage command values Vta function, and the system voltage command value Vdct can be raised or lowered so that the actual field adjustment value ΔIdr always matches the target field adjustment value ΔIdt. Become. After that, after the system voltage command value Vdct reaches the boost upper limit Vmax at time T3, the system voltage command value Vdct cannot be increased any further, so that the intermediate target value MM whose actual modulation factor M is the target modulation factor MT. It begins to rise above (= 0.707). As a result, the system voltage command value Vdct reaches the boost upper limit Vmax (step # 01: Yes in FIG. 13), and the actual modulation factor M becomes larger than the intermediate target value MM (step # 03 in FIG. 13). Therefore, the target modulation factor determination unit 56 matches the target modulation factor MT with the actual modulation factor M, and stops the adjustment of the system voltage command value Vdct using the modulation factor adjustment voltage command value Vtb. Then, when the actual modulation rate M exceeds the intermediate target value MM (= 0.707), overmodulation PWM control is started, and the control mode shifts from the second PWM control mode C5 to the second overmodulation PWM control mode C3. To do.

  Even after time T3, the actual modulation rate M gradually increases as the rotational speed ω increases, and at time T4, the actual modulation rate M reaches “0.78”, which is the maximum modulation rate Mmax. Between this time T3 and T4, the system voltage command value Vdct is maintained at the boost upper limit Vmax, but the actual field modulation value ΔIdr is set to the target by changing the actual modulation factor M as the rotational speed ω increases. A state matching the field adjustment value ΔIdt is maintained. Then, after time T4 after the actual modulation rate M becomes “0.78”, which is the maximum modulation rate Mmax, the control device 1 executes the rectangular wave control mode C4. After the time point T4, both the system voltage command value Vdct and the actual modulation factor M have reached the upper limit and cannot be adjusted even when the rotational speed ω increases. It rises above ΔIdt.

  According to the configuration of the present embodiment as described above, the field-weakening control is performed even during the execution of the PWM control mode CP executed in a state where the actual modulation rate M is relatively low (here, during the execution of the normal PWM control). The actual field adjustment value ΔIdr at that time can be made to coincide with the target field adjustment value ΔIdt. Accordingly, the actual field adjustment value ΔIdr can be adjusted to an appropriate value according to the operating state of the electric motors MG1 and MG2, and the efficiency of the entire system including the electric motors MG1 and MG2 and the electric motor driving device 2 can be improved. Is possible.

  In this embodiment as well, as in the first embodiment, the target field adjustment value ΔIdt is determined so as to increase as both the rotational speed ω and the target torque TM increase. Therefore, even when the target torque TM is gradually increased while the rotational speed ω is kept constant, or even when both the rotational speed ω and the target torque TM are gradually increased, the operation of the control device 1 is as follows. This is almost the same as described above.

4). Other Embodiments (1) In the above embodiment, the target field adjustment value acquisition unit 31 uses the actual field adjustment value as the target field adjustment value to be a control variable in the feedback control for determining the system voltage command value Vdct. A configuration in which ΔIdr is detected and acquired has been described as an example. However, the embodiment of the present invention is not limited to this. That is, feedback control for determining the system voltage command value Vdct is performed using the field adjustment command value ΔId determined by the field adjustment unit 12 of the inverter control command determination unit 7 as the target field adjustment value. Is also one preferred embodiment of the present invention. In this case, the actual field adjustment value detection unit 45 in FIG. 4 is replaced with a field adjustment command value acquisition unit that acquires the field adjustment command value ΔId from the inverter control command determination unit 7. Further, when the motor drive device 2 includes a plurality of DC / AC conversion units (for example, inverters 5 and 6) corresponding to the plurality of motors (for example, the motors MG1 and MG2), the first switching unit 41 performs actual modulation. It is preferable that the field adjustment command value ΔId from the inverter control command determination unit 7 corresponding to the DC / AC conversion unit having the highest rate M is input to the field adjustment command value acquisition unit.

(2) In each of the above embodiments, the case where the target field adjustment value ΔIdt is determined so as to increase as both the rotational speed ω and the target torque TM of the electric motors MG1, MG2 increase is described as an example. did. However, the embodiment of the present invention is not limited to this, and the target field adjustment value ΔIdt is set to one of the rotational speed ω (ω1, ω2) and the target torque TM (TM1, TM2) of the electric motors MG1, MG2. It is also one of the preferred embodiments of the present invention that the configuration is determined based only on one side. For example, the target field adjustment value ΔIdt can be determined to increase as the rotational speed ω of the electric motors MG1 and MG2 increases. In this case, only the rotational speed ω of either the first electric motor MG1 or the second electric motor MG2 is input to the target field adjustment value determination unit 32 of the voltage conversion command determination unit 8. Further, the target field adjustment value ΔIdt can be determined so as to increase as the target torque TM of the electric motors MG1 and MG2 increases. In this case, only the target torque TM of either the first motor MG1 or the second motor MG2 is input to the target field adjustment value determination unit 32 of the voltage conversion command determination unit 8.

(3) In the above embodiments, the configuration in which the target field adjustment value determination unit 32 determines the target field adjustment value ΔIdt based on the target field adjustment value map 46 has been described as an example. However, the embodiment of the present invention is not limited to this. The target field adjustment value determination unit 32 may be configured to calculate an appropriate target field adjustment value ΔIdt based on a predetermined arithmetic expression and variables such as the rotational speed ω and the target torque TM. This is one of the embodiments.

(4) In the above embodiments, the configuration in which the target field adjustment value determination unit 32 determines the target field adjustment value ΔIdt based on the target torque TM and the rotational speed ω of the electric motors MG1 and MG2 has been described as an example. However, the embodiment of the present invention is not limited to this. The target field adjustment value determination unit 32 may determine the target field adjustment value ΔIdt based on at least the target torque TM and the rotational speed ω of the AC motor. For example, in addition to the target torque TM and the rotational speed ω of the AC motor In another preferred embodiment of the present invention, the target field adjustment value ΔIdt is determined based on other information such as the temperature and operating time of the AC motor.

(5) In each of the embodiments described above, the voltage conversion command determination unit 8 matches the actual field adjustment value ΔIdr with the target field adjustment value ΔIdt and matches the actual modulation rate M with the target modulation rate MT. The case where the system voltage command value Vdct is determined has been described as an example. However, the embodiment of the present invention is not limited to this. The voltage conversion command determination unit 8 does not perform the process of determining the system voltage command value Vdct based on the actual modulation factor M, and simply sets the system voltage command value so that the actual field adjustment value ΔIdr matches the target field adjustment value ΔIdt. A configuration in which processing for determining Vdct is performed is also one preferred embodiment of the present invention. In this case, the voltage conversion command determination unit 8 can be configured not to include the third switch 43, the subtractor 50, and the amplifier 51 (the target modulation factor determination unit 56 in the third embodiment).

(6) In the first and second embodiments, the case where the target modulation rate MT is fixed to the maximum modulation rate Mmax (= 0.78) has been described as an example. However, the embodiment of the present invention is not limited to this. It is also a preferred embodiment of the present invention to set a different target modulation factor MT according to at least one of the rotational speed ω and the target torque TM of the AC motor. For example, in order to suppress the generation of torque ripple of the motor by executing the rectangular wave control mode C4 in the region where the rotational speed ω is low, the target modulation factor MT is set to the intermediate target value when the rotational speed ω is less than a predetermined threshold value. One of the preferred embodiments of the present invention is to set MM (= 0.707) and set the target modulation rate MT to the maximum modulation rate Mmax (= 0.78) above the threshold value. Further, the present invention is not limited to such an example, and it is also preferable to set a different target modulation factor MT according to the rotational speed ω, or to set a different target modulation factor MT according to the target torque TM.

(7) In each of the above-described embodiments, the case where the electric motor drive device 2 has two electric motors MG1 and MG2 as driving targets has been described as an example. However, the embodiment of the present invention is not limited to this. For example, it is one of the preferred embodiments of the present invention that the motor driving device 2 has a configuration in which only one AC motor is driven, or a configuration in which three or more AC motors are driven. . In any case, the motor drive device 2 includes a DC / AC converter (inverter) corresponding to each motor, and the control device 1 includes an inverter control command determination unit 7 corresponding to each DC / AC converter (inverter). A configuration is preferable. In the configuration in which only one AC motor is driven, the switches 41 to 43 and the modulation rate comparison unit 44 can be omitted from the configuration of the voltage conversion command determination unit 8 in each of the above embodiments. Conversely, in a configuration in which three or more AC motors are driven, it is necessary to increase the number of switching points in the switches 41 to 43. Also in this case, the voltage conversion command determination unit 8 is a DC AC that has the largest actual modulation factor M derived by the corresponding inverter control command determination unit 7 among the plurality of DC / AC conversion units (inverters). It is preferable that the converter operates as a target. As a vehicle drive device that drives three or more AC motors, for example, there is an in-wheel motor type drive device for an electric vehicle provided with one electric motor for each wheel.

(8) In each of the above-described embodiments, the case where the electric motor drive device 2 is configured as a device for driving the electric motors MG1 and MG2 used as the driving force source of the hybrid vehicle drive device has been described as an example. However, the embodiment of the present invention is not limited to this. For example, a control device for an electric motor drive device used in a drive device for an electric vehicle that does not include an internal combustion engine and uses one or a plurality of electric motors as a driving force source, a control device for an electric motor drive device targeted for an electric motor other than the vehicle, etc. In addition, the present invention is applicable.

  The present invention includes a voltage conversion unit that converts a power supply voltage from a DC power source to generate a desired system voltage, a DC / AC conversion unit that converts DC power having the system voltage into AC power and supplies the AC power to an AC motor; Can be suitably used for a control device that controls an electric motor drive device including

1: Control device 2: Motor drive device 3: DC power supply 4: Voltage conversion unit 5: First inverter (DC AC conversion unit)
6: Second inverter (DC / AC converter)
11: current command determination unit 12: field adjustment unit 13: voltage command determination unit 14: actual modulation factor derivation unit 15: mode control unit 31: target field adjustment value acquisition unit 32: target field adjustment value determination unit 33: System voltage determination unit MG1: first motor (AC motor)
MG2: Second motor (AC motor)
Vb: power supply voltage Vdc: system voltage Vdct: system voltage command value ω: rotational speed TM: target torque Id: basic d-axis current command value (current command value)
Iq: Basic q-axis current command value (current command value)
Ida: d-axis current command value after adjustment (= Id + ΔId)
Iqa: q-axis current command value after adjustment ΔId: field adjustment command value (target field adjustment value)
ΔIdr: real field adjustment value (target field adjustment value)
ΔIdt: Target field adjustment value R: Output possible range Vd: d-axis voltage command value (AC voltage command value)
Vq: q-axis voltage command value (AC voltage command value)
M: actual modulation rate MT: target modulation rate CP: PWM (pulse width modulation) control mode C4: rectangular wave control mode

Claims (7)

A voltage conversion unit that converts a power supply voltage from a DC power source to generate a desired system voltage; a DC / AC conversion unit that converts DC power supplied from the voltage conversion unit into AC power and supplies the AC power to the AC motor; A control device for controlling an electric motor drive device comprising:
Based on the target torque of the AC motor, a current command determination unit that determines a current command value that is a command value of a current supplied from the DC / AC conversion unit to the AC motor;
A field for adjusting the direction in which the field magnetic flux of the AC motor is weakened with respect to the current command value so that the current command value falls within a possible output range determined based on the system voltage and the rotational speed of the AC motor. A field adjustment unit that determines a field adjustment command value that is a command value of the magnetic adjustment value;
The actual field adjustment value, which is the actual field adjustment value detected based on the current supplied to the AC motor from the DC / AC converter and the current command value, or the field adjustment command value, A target field adjustment value acquisition unit that acquires the target field adjustment value;
A target field adjustment value determination unit that determines a target field adjustment value that is a control target value of the target field adjustment value based on the target torque of the AC motor and the rotational speed of the AC motor;
A system voltage determination unit that determines a system voltage command value that is a command value of the system voltage so as to match the target field adjustment value with the target field adjustment value;
The control apparatus of the electric motor drive device provided with. Based on the current command value and the rotational speed of the AC motor, a voltage command determination unit that determines an AC voltage command value that is a command value of an AC voltage supplied from the DC / AC converter to the AC motor;
An actual modulation rate deriving unit for deriving an actual modulation rate representing the magnitude of the AC voltage command value with respect to the system voltage;
The system voltage determining unit determines the system voltage command value so that the target field adjustment value is matched with the target field adjustment value and the actual modulation rate is matched with a predetermined target modulation rate. A control device for an electric motor drive device according to claim 1. A mode control unit that selects one of a plurality of control modes including a pulse width modulation control mode and a rectangular wave control mode based on the actual modulation rate and causes the DC / AC conversion unit to execute the mode control unit;
The motor drive device control device according to claim 2, wherein the target modulation rate is a value of the actual modulation rate that is a condition for starting the rectangular wave control mode. A mode control unit that selects one of a plurality of control modes including a pulse width modulation control mode and a rectangular wave control mode based on the actual modulation rate and causes the DC / AC conversion unit to execute the mode control unit;
The target modulation rate is a constant value set within the range of the actual modulation rate that is a condition for executing the pulse width modulation control mode when the system voltage is less than the upper limit value of the system voltage command value. 3. The motor drive device control device according to claim 2, wherein in a state where the system voltage is an upper limit value of the system voltage command value, a value that matches the actual modulation rate is set.   The system voltage command value is adjusted such that the current command value after adjustment of the current command value determined by the current command determination unit with the target field adjustment value becomes a value on the outer edge of the output possible range. The control device for the electric motor drive device according to any one of claims 1 to 4, wherein the control device is determined as follows.   6. The target field adjustment value is determined so as to increase as one or both of a rotational speed of the AC motor and a target torque of the AC motor become higher. 6. The control device for the electric motor drive device. The motor drive device includes a plurality of the DC / AC converters corresponding to each of the plurality of AC motors, and one voltage converter common to the plurality of DC / AC converters, and the voltage converter Is configured to generate the system voltage common to the plurality of DC-AC converters,
Corresponding to each of the plurality of DC / AC conversion units, the plurality of current command determination units, the plurality of field adjustment units, the DC command conversion based on the current command value and the rotational speed of the AC motor A plurality of voltage command determining units that determine an AC voltage command value that is a command value of an AC voltage supplied to the AC motor from a unit, and an actual modulation factor that represents a magnitude of the AC voltage command value with respect to the system voltage A plurality of actual modulation rate derivation units,
The target field adjustment value acquisition unit, the target field adjustment value determination unit, and the system voltage determination unit are derived by the corresponding actual modulation rate deriving unit among the plurality of DC / AC conversion units. The system voltage command value common to a plurality of the DC / AC converters is determined by operating on the DC / AC converter having the largest actual modulation rate, and the system voltage command value is determined according to any one of claims 1 to 6. The control device for the electric motor drive device.

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