Power converter control device, program, and power converter control method

Abstract

Provided is a power converter control device (60) applied to a system provided with a power storage unit (10), a rotary electric machine (20) having a plurality of phases of armature windings (24U -24W) and a rotor (21), and a power converter (30) that electrically connects the power storage unit and the armature windings and has upper and lower arm switches (SUH-SWL), the power converter control device comprising: a determination unit (100) that determines whether there is a temperature increase request for a part (10) subject to a temperature increase; and a switch control unit (101) that, when it is determined there is a temperature increase request, performs temperature increase control more than when it is determined there is no temperature increase request, and performs control so that the torque generated by the rotary electric machine is a command torque (Trq*), the switch control unit performing a ripple suppression process for reducing the magnetic flux of the rotor so as to reduce the magnitude of the angle formed by the q-axis of a dq coordinate system and the current vector flowing through the armature windings when it is determined in the temperature increase control that the torque ripple of the rotary electric machine is greater than a threshold value.

Description

Control device, program, and method for controlling a power converter CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2024-051094, filed on March 27, 2024, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a control device for a power converter, a program, and a control method for a power converter.

[0003] Conventionally, there has been known a control device that is applied to a system including a power converter and a rotating electric machine having an armature winding electrically connected to the power converter. One such control device raises the temperature of an object to be heated while driving the rotating electric machine. An example of such a control device is the control device disclosed in Patent Document 1.

[0004] Japanese Patent Application Laid-Open No. 2023-016559

[0005] There is still room for improvement in the technology for raising the temperature of an object to be heated while driving a rotating electric machine.

[0006] A primary object of the present disclosure is to provide a control device, a program, and a control method for a power converter that can raise the temperature of a temperature-raising target while driving a rotating electric machine.

[0007] The present disclosure relates to a power converter control device that is applied to a system including: a power storage unit; a rotating electric machine having a multi-phase armature winding and a rotor; and a power converter that electrically connects the power storage unit and the armature winding and has upper and lower arm switches, the power converter comprising: a determination unit that determines whether or not there is a temperature increase request for a part to be heated; and a switch control unit that, when it is determined that there is the temperature increase request, performs temperature increase control to increase the magnitude of a current vector flowing in the armature winding compared to when it is determined that there is no temperature increase request, and performs switching control of the upper and lower arm switches to control the torque generated by the rotating electric machine to a command torque, wherein, when it is determined in the temperature increase control that the torque ripple of the rotating electric machine is larger than a threshold value, the switch control unit performs ripple suppression processing to reduce the magnetic flux of the rotor to reduce the magnitude of the angle between the q-axis of a dq coordinate system and the current vector flowing in the armature winding.

[0008] In the temperature rise control, the control device increases the magnitude of the current vector flowing through the armature winding to raise the temperature of the temperature-raising target part, and controls the torque generated by the rotating electric machine to the command torque. When the temperature rise control is executed, the angle between the q-axis of the dq coordinate system and the current vector flowing through the armature winding (hereinafter referred to as the current advance angle) may be larger than when the temperature rise control is not executed. In this case, for example, there is a concern that the d-axis magnetic path including the stator and rotor of the rotating electric machine may become magnetically saturated, resulting in increased torque ripple in the rotating electric machine.

[0009] Therefore, when the switch control unit of the present disclosure determines that the torque ripple of the rotating electric machine is greater than a threshold value, it executes a ripple suppression process in the temperature rise control to reduce the magnetic flux of the rotor in order to reduce the magnitude of the current advance angle.

[0010] In the ripple suppression process, the magnetic flux of the rotor is reduced, thereby reducing the magnet torque. This makes it possible to reduce the magnitude of the current advance angle while controlling the torque generated by the rotating electric machine to the command torque. As a result, it is possible to suppress the occurrence of a situation in which the torque ripple of the rotating electric machine increases due to the execution of temperature rise control.

[0011] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which Fig. 1 is an overall configuration diagram of a system according to a first embodiment, Fig. 2 is a diagram showing an overview of a cooling system, Fig. 3 is a diagram showing changes in three-phase AC current and torque during normal control and temperature rise control, Fig. 4 is a diagram showing current vectors during temperature rise control in a dq coordinate system according to a comparative example, Fig. 5 is a diagram showing equal torque lines during temperature rise control in a dq coordinate system according to the first embodiment, Fig. 6 is a functional block diagram showing processing by a control device, Fig. 7 is a flowchart showing a processing procedure for temperature rise control, Fig. 8 is a flowchart showing a processing procedure for calculating torque ripple, Fig. 9 is a flowchart showing a processing procedure for a low magnetic flux mode, and Fig. 10 is a diagram showing changes in three-phase AC current, d-axis and q-axis currents, field current, and torque during normal control and temperature rise control. 11 is a diagram showing simulation results, FIG. 12 is a flowchart showing the processing procedure for temperature rise control according to the second embodiment, FIG. 13 is a flowchart showing the processing procedure for the low magnetic flux mode, FIG. 14 is a flowchart showing the processing procedure for the second mode, FIG. 15 is a flowchart showing the processing procedure for temperature rise control according to the third embodiment, FIG. 16 is a diagram showing the transitions of three-phase AC current, d-axis and q-axis currents, field current, and torque according to the comparative example, FIG. 17 is a diagram showing current vectors in a dq coordinate system according to the comparative example, FIG. 18 is a diagram showing the transitions of three-phase AC current, d-axis and q-axis currents, field current, and torque according to the fourth embodiment, FIG. 19 is a diagram showing current vectors in a dq coordinate system, and FIG. 20 is an overall configuration diagram of a system according to the fifth embodiment.

[0012] A control device according to a first embodiment of the present disclosure will now be described with reference to the drawings. A system including the control device of the present embodiment is mounted on a vehicle such as an electric vehicle or a hybrid vehicle.

[0013] As shown in Fig. 1, the system includes a storage battery 10 (corresponding to an "electricity storage unit"), two power converters, and a rotating electric machine 20. In this embodiment, the rotating electric machine 20 is a wound-field rotating electric machine. The rotating electric machine 20 is also a salient-pole machine, and has a forward salient pole characteristic in which the d-axis inductance Ld is larger than the q-axis inductance Lq.

[0014] The storage battery 10 is an assembled battery configured as a series connection of battery cells, which are single cells. The battery cells are, for example, secondary batteries such as lithium ion batteries.

[0015] The rotating electric machine 20 includes a rotor 21. The rotor 21 includes a rotor core and a plurality of field salient poles extending radially from the rotor core. A field winding 22 is wound around each of the field salient poles. The rotating shaft of the rotor 21 is capable of transmitting power to drive wheels 12 of the vehicle via a power transmission mechanism 11 provided in the vehicle. Torque generated when the rotating electric machine 20 functions as an electric motor is transmitted to the drive wheels 12 via the power transmission mechanism 11, causing the drive wheels 12 to rotate. This causes the vehicle to travel. The power transmission mechanism 11 includes, for example, a transmission and a shaft. The rotating electric machine 20 may be, for example, an in-wheel motor integrally provided with the drive wheels 12 of the vehicle, or an on-board motor provided on the vehicle body.

[0016] The rotating electric machine 20 includes a stator 23. The stator 23 includes an armature core and an armature winding. The armature core includes an annular back yoke portion and a plurality of teeth extending radially from the back yoke portion toward the rotor 21. The armature winding includes U-, V-, and W-phase windings 24U, 24V, and 24W that are star-connected with a 120° electrical angle offset from one another.

[0017] The system includes an inverter 30 (corresponding to a "first power converter") and a field energization circuit 40 (corresponding to a "second power converter"). The inverter 30 converts DC current from the storage battery 10 into AC current and supplies the AC current to the armature windings. The inverter 30 includes a series-connected arrangement of U-, V-, and W-phase upper-arm switches SUH, SVH, and SWH and U-, V-, and W-phase lower-arm switches SUL, SVL, and SWL. In this embodiment, the switches SUH, SVH, SWH, SUL, SVL, and SWL are N-channel MOSFETs. The switches SUH, SVH, SWH, SUL, SVL, and SWL include body diodes DUH, DVH, DWH, DUL, DVL, and DWL.

[0018] The drains, which are high-potential terminals of the U-, V-, and W-phase upper-arm switches SUH, SVH, and SWH, are connected to the positive terminal of the storage battery 10 via a high-potential electrical path Lp. The sources, which are low-potential terminals of the U-, V-, and W-phase lower-arm switches SUL, SVL, and SWL, are connected to the negative terminal of the storage battery 10 via a low-potential electrical path Ln. Each electrical path Lp, Ln is a conductive member such as a bus bar. The inverter 30 includes a first capacitor 31, which is a smoothing capacitor. The first capacitor 31 may be provided outside the inverter 30.

[0019] The field energization circuit 40 supplies current from the storage battery 10 to the field winding 22. In this embodiment, the field energization circuit 40 is a full-bridge circuit and includes a series connection of a first upper arm switch SH1 and a first lower arm switch SL1, and a series connection of a second upper arm switch SH2 and a second lower arm switch SL2. In this embodiment, the switches SH1, SH2, SL1, and SL2 are N-channel MOSFETs. The switches SH1, SH2, SL1, and SL2 include body diodes DH1, DH2, DL1, and DL2. When turned on, the switches SH1, SH2, SL1, and SL2 are bidirectional switching elements that allow current to flow from drain to source and from source to drain.

[0020] The drains, which are high-potential terminals of the first and second upper-arm switches SH1 and SH2, are connected to the positive terminal of the storage battery 10 via a high-potential electrical path Lp. The sources, which are low-potential terminals of the first and second lower-arm switches SL1 and SL2, are connected to the negative terminal of the storage battery 10 via a low-potential electrical path Ln. A first end of the field winding 22 is connected to the connection point between the first upper-arm switch SH1 and the first lower-arm switch SL1 via a brush (not shown). A second end of the field winding 22 is connected to the connection point between the second upper-arm switch SH2 and the second lower-arm switch SL2 via a brush (not shown). The field energization circuit 40 includes a second capacitor 41, which is a smoothing capacitor. The second capacitor 41 may be provided outside the field energization circuit 40. Furthermore, instead of the configuration in which the second capacitor 41 is provided individually in the field energizing circuit 40 and the first capacitor 31 is provided individually in the inverter 30, a configuration in which a common capacitor is provided in the inverter 30 and the field energizing circuit 40 may be adopted. In this case, for example, the second capacitor 41 may not be provided.

[0021] As shown in FIG. 2 , the system includes a device for cooling the inverter 30, the field energization circuit 40, the rotating electric machine 20, and the storage battery 10 when switching control of the inverter 30 is being performed to run the vehicle. Specifically, the system includes a circulation path 200 through which coolant circulates, an electric water pump 201, a radiator 202, and an electric fan 203. The water pump 201 is powered and driven to circulate the coolant. In the example shown in FIG. 2 , the inverter 30, the field energization circuit 40, the rotating electric machine 20, and the storage battery 10 are arranged in this order downstream of the water pump 201 in the circulation path 200. Note that the arrangement order of the components in the circulation path 200 is not limited to the order shown in FIG. 2 .

[0022] A radiator 202 is provided in circulation path 200 between water pump 201 and storage battery 10. Radiator 202 cools the coolant flowing in through circulation path 200 and supplies the cooled coolant to water pump 201. The coolant flowing into radiator 202 is cooled by wind blown against radiator 202 as the vehicle travels and wind blown against radiator 202 by rotating fan 203.

[0023] The water pump 201 and the fan 203 may be driven by a control device separate from the control device 60. However, in this embodiment, for convenience, it is assumed that the water pump 201 and the fan 203 are driven by the control device 60 provided in the system.

[0024] Returning to the description of FIG. 1 , the system includes a voltage sensor 50, a phase current sensor 51, a field current sensor 52, an angle sensor 53, a battery temperature sensor 54, a rotor temperature sensor 55, a stator temperature sensor 56, and a coolant temperature sensor 57. The voltage sensor 50 detects the voltage of the storage battery 10. The phase current sensor 51 detects phase currents flowing through at least two of the U-, V-, and W-phase windings 24U, 24V, and 24W. The field current sensor 52 detects a field current (hereinafter, field current Ifr) flowing through the field winding 22. The angle sensor 53 detects the rotation angle (specifically, the electrical angle) of the rotor 21. The battery temperature sensor 54 detects the temperature of the storage battery 10. The rotor temperature sensor 55 detects the temperature of the rotor 21. The stator temperature sensor 56 detects the temperature of the stator 23. The coolant temperature sensor 57 detects the temperature of the coolant flowing through the circulation path 200.

[0025] The system includes a control device 60 and a host control device 80 that is higher in level than the control device 60. The detection values ​​of the sensors 50 to 57 are input to the control device 60.

[0026] The control device 60 is an electronic control unit and includes a processor 60a and a storage unit 60b as hardware. The upper control device 80 is also an electronic control unit and includes a processor (not shown) and a storage unit (not shown) as hardware. The control device 60 and the upper control device 80 are capable of exchanging information.

[0027] The memory unit 60b includes memory and storage as hardware. The memory is a storage device for storing data used in the processing of the control device 60. The memory provides the processor 60a with a working area for temporary use when the processor 60a performs processing, for example. The memory includes, for example, ROM or RAM. The storage is a storage device for storing various programs and data to be read and executed by the processor 60a, and is a non-transitory tangible storage medium. The storage includes, for example, an HDD or flash memory. The storage stores program information and the like for the processing shown in Figures 7 to 9 and 12 to 15, which will be described later.

[0028] The control device 60 performs switching control of each switch constituting the field energization circuit 40 to excite the field winding 22. More specifically, the control device 60 performs switching control so that a first state and a second state alternately occur in order to control the field current Ifr detected by the field current sensor 52 to the field target current If*. The first state is a state in which the first upper arm switch SH1 and the second lower arm switch SL2 are turned on, and the second upper arm switch SH2 and the first lower arm switch SL1 are turned off. The second state is a state in which the first upper arm switch SH1 and the second lower arm switch SL2 are turned off, and the second upper arm switch SH2 and the first lower arm switch SL1 are turned on.

[0029] While the field winding 22 is excited, the control device 60 performs switching control of each switch constituting the inverter 30 based on the detection values ​​of the sensors 50 to 57 to feedback control the control variable of the rotating electric machine 20 to a command value. In this embodiment, the control variable is torque. In each phase, the upper arm switch and the lower arm switch are alternately turned on. This feedback control causes the rotor 21 to rotate.

[0030] Next, the temperature rise control of the temperature rise target part executed by the control device 60 will be described. Note that in this embodiment, the temperature rise target part is the storage battery 10. The temperature rise control is a control that generates heat by controlling the switching of the inverter 30 and the field current circuit 40 when the temperature Tr of the storage battery 10 falls below the target temperature T* while normal control is being executed. Here, normal control is a control that is executed to control the torque generated by the rotating electric machine 20 (hereinafter, the generated torque Trqr) to the command torque Trq*. The heat generated by the temperature rise control is transferred to the storage battery 10 via the coolant circulating through the circulation path 200 by driving the water pump 201. The temperature rise control is continued, for example, until the temperature Tr of the storage battery 10 reaches the target temperature T*. Furthermore, the water pump 201 continues to be driven at least while the temperature rise control is being executed.

[0031] During temperature rise control, the control device 60 controls the generated torque Trqr to the command torque Trq*, while performing switching control of the inverter 30 so that the magnitude of the current vector (hereinafter referred to as the current vector) flowing through the U, V, and W phase windings 24U, 24V, and 24W is larger than that of normal control.

[0032] Incidentally, torque ripple may be larger in the temperature rise control shown in Fig. 3(B) than in the normal control shown in Fig. 3(A). In Fig. 3, the upper part shows the transition of the three-phase AC current flowing through the U-, V-, and W-phase windings 24U, 24V, and 24W, and the lower part shows the transition of the generated torque Trqr.

[0033] In the temperature rise control, the magnitude of the current vector is increased, and therefore the amplitude of the three-phase AC current is increased compared to when normal control is performed, as shown in the upper part of Figure 3(B). In this case, as shown in the lower part, the width of the torque ripple (hereinafter referred to as ripple Ripr), which is the fluctuation of the generated torque Trqr, increases and exceeds the ripple allowable value Ripth (corresponding to the "threshold value"). Here, the ripple allowable value Ripth is the width of the torque ripple allowable with respect to the average value of the generated torque Trqr, and is set to be larger, for example, as the average value of the generated torque Trqr increases.

[0034] In order to prevent the ripple Ripr from exceeding the allowable ripple value Ripth, the AC signal Sac is superimposed on a d-axis target current Id*, which is a target value for the d-axis current (hereinafter referred to as the d-axis current Idr) flowing through the U-, V-, and W-phase windings 24U, 24V, and 24W, or a q-axis target current Iq*, which is a target value for the q-axis current (hereinafter referred to as the q-axis current Iqr). As a result, as shown in FIG. 3C , the amplitude of the three-phase AC current can be maintained while the ripple Ripr is kept below the allowable ripple value Ripth.

[0035] Here, even when the AC signal Sac is superimposed on the d-axis target current Id* or the q-axis target current Iq*, the ripple Ripr may become larger than the allowable ripple value Ripth. This point will be described with reference to FIG.

[0036] The horizontal axis of Figure 4 represents the d-axis current Idr, and the vertical axis represents the q-axis current Iqr. Ltcr represents an equal torque line formed by a combination of the d- and q-axis currents Idr and Iqr when the generated torque Trqr is the same. Lic represents a current limit circle, which is the upper limit of the magnitude of the current vector.

[0037] In normal control, the current operating point of the rotating electric machine 20 is controlled to, for example, the most efficient point on the equal torque line Ltcr. For example, in normal control, the current operating point is the first operating point OP1, and the current vector is the first current vector Vt1. On the other hand, in temperature increase control, the current operating point is controlled to be on the equal torque line Ltcr, and the magnitude of the current vector is greater than the magnitude of the first current vector Vt1. For example, in temperature increase control, the current operating point is the second operating point OP2. In this case, the current vector is the second current vector Vt2, and the magnitude of the second current vector Vt2 is greater than the magnitude of the first current vector Vt1. This allows the control device 60 to increase the temperature of the storage battery 10 while suppressing fluctuations in the generated torque Trqr.

[0038] When the magnitude of the current vector is increased beyond the magnitude of the second current vector Vt2 while maintaining the generated torque Trqr, the angle between the q-axis and the current vector (hereinafter, the current advance angle θr) increases. Here, the larger the current advance angle θr, the larger the d-axis current Idr flowing through the U-, V-, and W-phase windings 24U, 24V, and 24W. In this case, for example, the d-axis magnetic path including the stator 23 and the rotor 21 becomes magnetically saturated, and the ripple Ripr increases. In FIG. 4 , the maximum angle θmax corresponds to the ripple allowable value Ripth. When the current advance angle θr is greater than the maximum angle θmax, the ripple Ripr exceeds the ripple allowable value Ripth.

[0039] For this reason, for example, when the current operating point is controlled to the third operating point OP3, there is a concern that the ripple Ripr will become larger than the allowable ripple value Ripth. In this case, to suppress the ripple Ripr, for example, the current operating point is moved from the third operating point OP3 to the second operating point OP2. This reduces the heat generated by the temperature rise control, which may limit the temperature rise control, such as making it impossible to raise the temperature Tr of the storage battery 10 to the target temperature T*. Therefore, in this embodiment, the magnetic flux of the rotor 21 is reduced during the temperature rise control, thereby preventing the temperature rise control from being limited.

[0040] 5 shows first equal torque lines Ltc1 and second equal torque lines Ltc2, which represent the same torque. The first equal torque lines Ltc1 are lines obtained when the magnetic flux φfr generated in the field winding 22 is equal to the first magnetic flux φf1, and the second equal torque lines Ltc2 are lines obtained when the magnetic flux φfr is equal to the second magnetic flux φf2. Here, the second magnetic flux φf2 is smaller than the first magnetic flux φf1.

[0041] When the current operating point is controlled to lie on the first constant torque contour Ltc1, even if the magnitude of the current vector is equal to or smaller than the current limit circle Lic, the current advance angle θr may be greater than the maximum angle θmax, for example, in the region indicated by the dashed line. This raises concerns that temperature rise control may be restricted. Therefore, the control device 60 reduces the magnetic flux φfr from the first magnetic flux φf1 to the second magnetic flux φf2. This causes the control device 60 to move the first constant torque contour Ltc1 to the second constant torque contour Ltc2. When the current operating point is controlled to lie on the second constant torque contour Ltc2 and the magnitude of the current vector is equal to or smaller than the current limit circle Lic, the current advance angle can be prevented from being greater than the maximum angle θmax.

[0042] The relationship between the generated torque Trqr, the magnetic flux φfr, and the current vector will be described in detail below.

[0043] The generated torque Trqr is made up of a magnet torque TM and a reluctance torque TR, as expressed by the following equation (eq1).

[0044] Trqr=TM+TR (eq1) From the above equation (eq1), when the generated torque Trqr is constant, the reluctance torque TR can be increased by reducing the magnet torque TM. Here, the magnet torque TM is expressed by the following equation (eq2).

[0045] TM=P·φfr·Iqr (eq2) In the above equation (eq2), P represents the number of pole pairs of the rotating electric machine 20. Here, the magnetic flux φfr is the magnetic flux generated when the field current Ifr flows through the field winding 22. When the coupling inductance Lmf is used, the magnetic flux φfr is expressed as "φfr=Lmf×Ifr". The coupling inductance Lmf (>0) is the inductance of the d-axis magnetic path including the back yoke portion and teeth portion of the stator 23 and the rotor core and field salient pole portion of the rotor 21.

[0046] From the above equations (eq1) and (eq2), it is possible to increase the reluctance torque TR by reducing the magnetic flux φfr. Here, the reluctance torque TR is expressed by the following equation (eq3).

[0047] TR=P·(Ld−Lq)·Idr·Iqr (eq3) In the above equation (eq3), Ld represents the d-axis inductance, and Lq represents the q-axis inductance.

[0048] From equation (eq3) above, when the reluctance torque TR increases, the magnitude of the current vector can be increased and the ratio of the q-axis current Iqr to the d-axis current Idr (=Iqr / Idr) can be increased. In this way, by reducing the magnetic flux φfr, the magnitude of the current vector can be increased and the current advance angle θr can be reduced while maintaining the generated torque Trqr.

[0049] FIG. 6 shows a block diagram of the temperature increase control executed by the control device 60.

[0050] The control device 60 includes a determination unit 100 and a switch control unit 101. The determination unit 100 determines whether or not there is a temperature increase request for the storage battery 10 during execution of normal control. The determination unit 100 determines that there is a temperature increase request, for example, on the condition that it determines that a temperature increase command has been input from the upper control device 80. The upper control device 80, for example, acquires the temperature Tr of the storage battery 10, and inputs the temperature increase command to the control device 60 when it determines that the temperature Tr of the storage battery 10 is lower than the target temperature T*. The temperature Tr of the storage battery 10 used in the upper control device 80 is, for example, a value detected by the battery temperature sensor 54.

[0051] If the judgment unit 100 determines that a temperature increase command has been input and that the heat generated by normal control is insufficient to increase the temperature Tr of the storage battery 10 to the target temperature T*, it determines that a temperature increase request exists.

[0052] The switch control unit 101 receives the determination result of the determination unit 100. In addition, the command torque Trq* and the temperature Tr of the storage battery 10 are input from the higher-level control device 80. When performing temperature rise control, the switch control unit 101 determines whether to perform the temperature rise control in a high magnetic flux mode or a low magnetic flux mode (corresponding to "ripple suppression processing"). In this case, the switch control unit 101 calculates a ripple allowable value Ripth and an estimated ripple Ripc.

[0053] The switch control unit 101 calculates, for example, an allowable value of the generated torque Trqr based on the rotation speed Nr of the rotor 21, and calculates an allowable ripple value Ripth such that the generated torque Trqr does not exceed the allowable value.

[0054] The estimated ripple Ripc can be calculated, for example, by the following method. The switch control unit 101 calculates the d-axis target current Id* and the q-axis target current Iq* based on the magnetic flux φfr, the command torque Trq*, and the temperature difference ΔTr (=T*-Tr) between the target temperature T* and the temperature Tr of the storage battery 10. The switch control unit 101 may calculate the magnetic flux φfr based on the field current Ifr. The field current Ifr is, for example, a detection value of the field current sensor 52. The switch control unit 101 calculates the d-axis target current Id* and the q-axis target current Iq* so that the current vector increases as the temperature difference ΔTr increases. The switch control unit 101 may calculate the d-axis target current Id* and the q-axis target current Iq* based on, for example, map information that associates the command torque Trq*, the magnetic flux φfr, the temperature difference ΔTr, and the d-axis and q-axis target currents Id* and Iq*.

[0055] The switch control unit 101 adds an AC signal Sac to the calculated d-axis target current Id* or q-axis target current Iq* to suppress torque ripple in the rotating electric machine 20. The AC signal Sac is a signal added to suppress, for example, the sixth-order harmonic component of the torque ripple. Specifically, the AC signal Sac is an AC signal having an opposite phase to the phase of the waveform of the predicted torque ripple. Hereinafter, for convenience, it is assumed that the AC signal Sac is added to the d-axis target current Id*. The switch control unit 101 calculates the generated torque Trqr based on the above equations (eq1) to (eq3), the magnetic flux φfr, the d-axis target current Id* to which the AC signal Sac has been added, and the q-axis target current Iq*. The switch control unit 101 calculates the estimated ripple Ripc based on the calculated generated torque Trqr. The switch control unit 101 may calculate the estimated ripple Ripc based on, for example, map information in which the generated torque Trqr and the ripple Ripr are associated with each other.

[0056] The switch control unit 101 determines whether the calculated estimated ripple Ripc is equal to or less than the ripple allowable value Ripth. If the switch control unit 101 determines that the estimated ripple Ripc is equal to or less than the ripple allowable value Ripth, the switch control unit 101 selects the high flux mode. On the other hand, if the switch control unit 101 determines that the estimated ripple Ripc is greater than the ripple allowable value Ripth, the switch control unit 101 selects the low flux mode.

[0057] When the high magnetic flux mode is selected, the switch control unit 101 inputs switching signals to each of the switches SUH, SUL, SVH, SVL, SWH, and SWL of the inverter 30 to pass the d-axis target current Id* to which the AC signal Sac has been added and the q-axis target current Iq* through the U-, V-, and W-phase windings 24U, 24V, and 24W.

[0058] When the low magnetic flux mode is selected, the switch control unit 101 controls the generated torque Trqr to the command torque Trq*, while reducing the field target current If* to reduce the magnetic flux φfr. Specifically, the switch control unit 101 reduces the field target current If* under the conditions that the magnitude of the current vector is made equal to that in the high magnetic flux mode and the current advance angle θr is made smaller than that in the high magnetic flux mode.

[0059] The switch control unit 101 calculates the d- and q-axis target currents Id* and Iq* in the low magnetic flux mode based on the above equations (eq1) to (eq3) and the reduced field target current If*. The switch control unit 101 may calculate the d- and q-axis target currents Id* and Iq* based on, for example, map information that correlates the command torque Trq*, the field target current If*, the temperature difference ΔTr, and the d- and q-axis target currents Id* and Iq*.

[0060] The switch control unit 101 inputs switching signals to the switches SH1, SL1, SH2, and SL2 of the field energization circuit 40 so as to pass the reduced field target current If* through the field winding 22. The switch control unit 101 also inputs switching signals to the switches SUH, SUL, SVH, SVL, SWH, and SWL of the inverter 30 so as to pass the calculated d- and q-axis target currents Id* and Iq* through the U-, V-, and W-phase windings 24U, 24V, and 24W.

[0061] 7 is a flowchart showing the procedure for the temperature rise control executed by the control device 60. This process is repeatedly executed at a predetermined control cycle during execution of normal control. The calculation method in each of the following steps is the same as that described with reference to FIG. 6 and the like.

[0062] In steps S10 and S11, the determination unit 100 determines whether there is a request to increase the temperature of the storage battery 10. In step S10, it determines whether a temperature increase command has been input from the upper control device 80. In step S11, the determination unit 100 determines whether the temperature Tr of the storage battery 10 can be increased to the target temperature T* by the heat generated by normal control. If the determination in steps S10 and S11 is affirmative, it is determined that there is a request to increase the temperature of the storage battery 10, and the process proceeds to step S12. The following processing is executed by the switch control unit 101.

[0063] In step S12, a ripple tolerance value Ripth is calculated. In step S13, an estimated ripple Ripc is calculated. This process will be described below with reference to FIG.

[0064] In step S30, the command torque Trq* is obtained from the upper level control device 80. In step S31, the temperature Tr of the storage battery 10 is obtained from the upper level control device 80. In step S32, the magnetic flux φfr is calculated.

[0065] In step S33, the d-axis target current Id* and the q-axis target current Iq* are calculated based on the command torque Trq* obtained in step S30, the temperature Tr of the storage battery 10 obtained in step S31, and the magnetic flux φfr calculated in step S32.

[0066] In step S34, an AC signal Sac is calculated, and the calculated AC signal Sac is added to the d-axis target current Id* or the q-axis target current Iq* calculated in step S33. Here, if the q-axis target current Iq* is greater than the d-axis target current Id*, the AC signal Sac should be added to the q-axis target current Iq* to prevent a negative d-axis current Idr from flowing. On the other hand, if the d-axis target current Id* is greater than the q-axis target current Iq*, the AC signal Sac should be added to the d-axis target current Id*. For convenience, it will be assumed below that the AC signal Sac is added to the d-axis target current Id*.

[0067] In step S35, an estimated ripple Ripc is calculated.

[0068] 7, in step S14, it is determined whether the estimated ripple Ripc is equal to or less than the ripple allowable value Ripth. If it is determined in step S14 that the estimated ripple Ripc is equal to or less than the ripple allowable value Ripth, the process proceeds to step S15. In step S15, the high magnetic flux mode is selected, and the process proceeds to step S16.

[0069] In step S16, the switching of each switch SUH, SUL, SVH, SVL, SWH, and SWL of the inverter 30 is controlled so that the d-axis target current Id* to which the AC signal Sac has been added in step S34 of FIG. 8 and the q-axis target current Iq* calculated in step S33 flow through the U-, V-, and W-phase windings 24U, 24V, and 24W.

[0070] In step S17, it is determined whether the motor temperature Tmotr is equal to or lower than the motor temperature threshold value Tmotth. Here, the motor temperature Tmotr is, for example, the higher of the temperature of the rotor 21 and the temperature of the stator 23. The temperature of the rotor 21 is, for example, a value detected by the rotor temperature sensor 55. The temperature of the stator 23 is, for example, a value detected by the stator temperature sensor 56. If it is determined in step S17 that the motor temperature Tmotr is equal to or lower than the motor temperature threshold value Tmotth, the process proceeds to step S18.

[0071] In step S18, it is determined whether the coolant temperature Tcolr is greater than the water temperature threshold value Tcolth. Here, the coolant temperature Tcolr is, for example, a value detected by the coolant temperature sensor 57. Note that the coolant temperature Tcolr may be the temperature of a refrigerant other than water that cools the system, such as oil. If it is determined in step S18 that the coolant temperature Tcolr is equal to or less than the water temperature threshold value Tcolth, the process proceeds to step S16, where switching control continues.

[0072] If it is determined in step S17 that the motor temperature Tmotr is greater than the motor temperature threshold Tmotth, or if it is determined in step S18 that the coolant temperature Tcolr is greater than the water temperature threshold Tcolth, the process proceeds to step S19, where normal control is executed.

[0073] If it is determined in step S14 that the estimated ripple Ripc is greater than the allowable ripple value Ripth, the process proceeds to step S20, where the low flux mode is selected. The process when the low flux mode is selected will be described below with reference to FIG.

[0074] In step S40, the generated torque Trqr is controlled to the command torque Trq*, while the magnitude of the current vector is made equal to that in the high magnetic flux mode and the current advance angle θr is made smaller than that in the high magnetic flux mode, thereby reducing the field target current If*.

[0075] In step S41, the d-axis and q-axis target currents Id* and Iq* in the low magnetic flux mode are calculated based on the command torque Trq*, the reduced field target current If*, and the temperature difference ΔTr.

[0076] 7, in step S16, the switches SH1, SL1, SH2, and SL2 of the field energization circuit 40 are switched and controlled so that the field target current If* reduced in step S40 flows through the field winding 22. Also, the switches SUH, SUL, SVH, SVL, SWH, and SWL of the inverter 30 are switched and controlled so that the d- and q-axis target currents Id* and Iq* calculated in step S41 flow through the U-, V-, and W-phase windings 24U, 24V, and 24W.

[0077] In contrast to the normal control shown in FIG. 10A , in the high flux mode heating control shown in FIG. 10B , the initial amplitude Iini, which is the amplitude of the three-phase current in the normal control, is set to the heating amplitude Ih, thereby increasing the heat generated from the U-, V-, and W-phase windings 24U, 24V, and 24W. Furthermore, the heat generated from the U-, V-, and W-phase windings 24U, 24V, and 24W is transferred to the storage battery 10, thereby raising the temperature of the heating target. Compared to the normal control, the high flux mode heating control results in a larger torque ripple. In contrast, in the low flux mode heating control shown in FIG. 10C , the field current Ifr is reduced from the initial field current Ifini to the low field current Iflow. The high flux mode and the low flux mode have the same heating amplitude Ih and average torque Tini of the three-phase current. Therefore, in the low magnetic flux mode, it is possible to raise the temperature of the object to be heated while maintaining the average torque Tini, and also to reduce the torque ripple.

[0078] Figure 11 shows simulation results of the generated torque Trqr in each mode. Figure 11(A) shows the time transition of the generated torque Trqr when temperature rise control is performed in high magnetic flux mode. Figure 11(B) shows the time transition of the generated torque Trqr when temperature rise control is performed in low magnetic flux mode. Compared to the high magnetic flux mode, the torque ripple of the rotating electric machine 20 is smaller in the low magnetic flux mode.

[0079] As described above, in this embodiment, in the low magnetic flux mode, the magnetic flux φfr of the rotor 21 is reduced, thereby reducing the magnet torque TM. Therefore, the control device 60 can increase the reluctance torque TR while controlling the generated torque Trqr to the command torque Trq*. In this case, the control device 60 can reduce the magnitude of the current advance angle θr while maintaining the magnitude of the current vector flowing through the U-, V-, and W-phase windings 24U, 24V, and 24W. This makes it possible to maintain the heat generated by the temperature rise control while suppressing the occurrence of situations in which the torque ripple becomes large.

[0080] Second Embodiment A second embodiment will be described below with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, the temperature of the stator 23 and the temperature of the rotor 21 are used as the temperature of the rotating electrical machine 20 in the temperature increase control. In addition, in the low magnetic flux mode, switching is performed between a first mode and a second mode. The magnetic flux of the rotor 21 in the first mode is made smaller than the magnetic flux of the rotor 21 in the second mode.

[0081] 12, after steps S10 to S16 are executed, in step S50, it is determined whether the stator temperature Tstar, which is the temperature of the stator 23, is equal to or lower than the stator temperature threshold Tstat. The stator temperature threshold Tstat is, for example, the upper allowable temperature limit of the stator 23. The stator temperature Tstar may be, for example, a value detected by the stator temperature sensor 56, or may be a value calculated based on the field current Ifr. If it is determined that the stator temperature Tstar is equal to or lower than the stator temperature threshold Tstat, the process proceeds to step S51.

[0082] In step S51, it is determined whether the rotor temperature Trotr, which is the temperature of the rotor 21, is equal to or lower than the rotor temperature threshold Trotth. The rotor temperature threshold Trotth is, for example, the upper allowable temperature limit of the rotor 21. The rotor temperature Trotr may be, for example, a value detected by the rotor temperature sensor 55, or may be a value calculated based on the d-axis and q-axis currents Idr and Iqr. If it is determined that the rotor temperature Trotr is equal to or lower than the rotor temperature threshold Trotth, the process proceeds to step S18.

[0083] If it is determined in step S50 that the stator temperature Tstar is greater than the stator temperature threshold value Tstath, or if it is determined in step S51 that the rotor temperature Trotr is greater than the rotor temperature threshold value Trotth, the process proceeds to step S19.

[0084] Next, a process when it is determined in step S14 that the estimated ripple Ripc is larger than the permissible ripple value Ripth and the low magnetic flux mode is selected will be described with reference to FIG.

[0085] After steps S40 and S41 are executed, the first mode is executed in step S60. In this embodiment, the field target current If* reduced in step S40 is referred to as the first field target current If1*. In the first mode, the switches SH1, SL1, SH2, and SL2 of the field energization circuit 40 are switched and controlled so that the first field target current If1* flows through the field winding 22. Furthermore, the switches SUH, SUL, SVH, SVL, SWH, and SWL of the inverter 30 are switched and controlled so that the d- and q-axis target currents Id* and Iq* calculated in step S41 flow through the U-, V-, and W-phase windings 24U, 24V, and 24W.

[0086] In step S61, the controller 60 determines the required state of the temperature rise control. Specifically, it determines whether the temperature rise efficiency is prioritized between the efficiency of the temperature rise control and the amount of heat generated by the temperature rise control (specifically, the amount of heat generated per unit time). A case in which the temperature rise efficiency is prioritized occurs, for example, when it is necessary to raise the temperature of the object to be heated in a short period of time. A case in which the amount of heat generated by the temperature rise control is prioritized occurs, for example, when the temperature Tr of the storage battery 10 is lower than the target temperature T*. The controller 60 determines that the temperature rise efficiency is prioritized when, for example, a command to prioritize the temperature rise efficiency is input from the upper controller 80.

[0087] If it is determined that the temperature rise efficiency has priority, the process proceeds to step S50. If a negative determination is made in step S50 or step S51, the normal control of step S19 in Fig. 12 is executed. On the other hand, if a positive determination is made in steps S50 and S51 and a negative determination is made in step S18, the process proceeds to step S60, where the first mode is continued.

[0088] In the low magnetic flux mode, the magnetic flux φfr of the rotor 21 is reduced. In this case, at least one of the d-axis current Idr and the q-axis current Iqr is increased to maintain the generated torque Trqr. This increases the temperature of the stator 23 to which the U-, V-, and W-phase windings 24U, 24V, and 24W are assembled. Therefore, by continuing the first mode when the stator temperature Tstar is equal to or lower than the stator temperature threshold Tstath, it is possible to prevent the stator 23 from overheating.

[0089] On the other hand, if it is determined in step S61 that the amount of heat generated by the temperature increase control is prioritized over the efficiency of the temperature increase control, the process proceeds to step S62, where the second mode is executed. This process will be described below with reference to FIG. 14.

[0090] In step S70, a second field target current If2* is calculated, which is larger than the first field target current If1*. The second field target current If2* has a value smaller than the field current Ifr in normal control.

[0091] In step S71, the d-axis and q-axis target currents Id* and Iq* are calculated based on the command torque Trq* and second field target current If2* acquired in step S30 of FIG.

[0092] In step S72, the switches SH1, SL1, SH2, and SL2 of the field energization circuit 40 are switched and controlled so that the second field target current If2* calculated in step S70 flows through the field winding 22. Also, the switches SUH, SUL, SVH, SVL, SWH, and SWL of the inverter 30 are switched and controlled so that the d- and q-axis target currents Id* and Iq* calculated in step S71 flow through the U-, V-, and W-phase windings 24U, 24V, and 24W.

[0093] In step S73, it is determined whether the stator temperature Tstar is equal to or less than the stator temperature threshold value Tstath. If it is determined that the stator temperature Tstar is equal to or less than the stator temperature threshold value Tstath, the process proceeds to step S51. On the other hand, if it is determined that the stator temperature Tstar is greater than the stator temperature threshold value Tstath, the process proceeds to step S70, where the second field target current If2* is increased. In this case, the second field target current If2* is increased so that it is smaller than the field current Ifr under normal control.

[0094] As described above, the magnitude of the current flowing through the field winding 22 and the magnitude of the current flowing through the U-, V-, and W-phase windings 24U, 24V, and 24W differ between the first mode and the second mode. Specifically, in the first mode, the current flowing through the field winding 22 is smaller than in the second mode. Also, in the first mode, the current flowing through the U-, V-, and W-phase windings 24U, 24V, and 24W is larger than in the second mode. Therefore, when the first mode is executed, the temperature of the stator 23 is raised preferentially between the stator 23 and the rotor 21, and when the second mode is executed, the temperature of the rotor 21 is raised preferentially between the stator 23 and the rotor 21.

[0095] In this way, by switching between the first mode and the second mode, in which different currents are passed through the field winding 22, the ratio of heat generated by the stator 23 to heat generated by the rotor 21 can be changed. Here, the heat recovery efficiency from the stator 23 differs from the heat recovery efficiency from the rotor 21. Specifically, for example, heat generated from the U-, V-, and W-phase windings 24U, 24V, and 24W is recovered through a cooling passage provided in the housing of the stator 23 to which the U-, V-, and W-phase windings 24U, 24V, and 24W are assembled. On the other hand, heat generated from the rotor 21 is recovered, for example, through oil that cools the field winding 22. Therefore, the heat recovery efficiency from the stator 23 is higher than that from the rotor 21. Furthermore, because the resistance of the field winding 22 is higher than the resistance of the U-, V-, and W-phase windings 24U, 24V, and 24W, the amount of heat generated by the rotor 21 is greater than the amount of heat generated by the stator 23.

[0096] Therefore, when priority is given to the efficiency of the temperature rise control, the control device 60 executes a first mode in which the stator 23, which has a high heat recovery efficiency, is heated preferentially. Furthermore, when priority is given to the amount of heat generated by the temperature rise control, the control device 60 executes a second mode in which the rotor 21, which generates a large amount of heat, is heated preferentially. This improves the efficiency of the temperature rise control.

[0097] Third Embodiment A third embodiment will be described below with reference to the drawings, focusing on differences from the second embodiment. In this embodiment, as shown in Fig. 15 , the first mode and the second mode are switched based on the temperature of the stator 23.

[0098] Specifically, after steps S40, S41, and S60 are executed, in step S50, it is determined whether the stator temperature Tstar is equal to or less than the stator temperature threshold Tstat. If it is determined that the stator temperature Tstar is equal to or less than the stator temperature threshold Tstat, the process proceeds to step S51. On the other hand, if it is determined that the stator temperature Tstar is greater than the stator temperature threshold Tstat, the process proceeds to step S62, where the second mode is executed.

[0099] As described above, overheating of the stator 23 can be prevented by switching between a first mode in which the stator 23 is heated preferentially and a second mode in which the rotor 21 is heated preferentially based on the stator temperature Tstar.

[0100] Fourth Embodiment A fourth embodiment will be described below with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, when the command torque Trq* changes by a predetermined amount during execution of the temperature rise control in the low magnetic flux mode, the temperature rise control is paused. For convenience, the following description will be given taking as an example a case where the command torque Trq* increases by the predetermined amount.

[0101] FIG. 16 illustrates the transitions of parameters in a comparative example different from this embodiment. Specifically, FIG. 16 illustrates the transitions of the three-phase currents, d-axis current Idr and q-axis current Iqr, field current Ifr, and generated torque Trqr when command torque Trq* is increased during low-flux mode temperature rise control. To change generated torque Trqr from pre-change torque Tfor to post-change torque Tlat, field current Ifr is increased from pre-change field current Iffor to post-change field current Iflat. Here, to maintain the magnitude of the current vector before and after the change in generated torque Trqr, pre-change d-axis current Idfor is decreased to post-change d-axis current Idlat. Furthermore, pre-change q-axis current Iqfor is increased to post-change q-axis current Iqlat. This point will be described in more detail with reference to FIG. 17 .

[0102] 17, LIfor indicates a pre-change torque line which is an equal torque line when the field current Ifr is the pre-change field current Ifor, and LIflat indicates a post-change torque line which is an equal torque line when the field current Ifr is the post-change field current Iflat.

[0103] Here, before the command torque Trq* is changed, the current operating point is assumed to be a pre-change operating point OPfor. In this case, when the command torque Trq* is changed and the generated torque Trqr is changed from the pre-change torque Tfor to the post-change torque Tlat, the current operating point is controlled to a post-change operating point OPlat. As a result, the magnitudes of the pre-change current vector Vtfor and the post-change current vector Vtlat are made equal, and the current operating point is controlled to be on the post-change torque line LIflat. In this case, for example, there is a concern that a torque shock may occur due to a large amount of change in the d-axis current Idr.

[0104] Therefore, in this embodiment, when the command torque Trq* is increased during the execution of the temperature rise control in the low magnetic flux mode, the temperature rise control is first stopped and normal control is executed. Next, in the normal control, the generated torque Trqr is increased. Then, the temperature rise control in the low magnetic flux mode is resumed. This process will be described with reference to FIGS. 18 and 19.

[0105] 18, temperature rise control in the low magnetic flux mode is executed in the range from timing θ0 to timing θ1. Here, when the control device 60 determines that the command torque Trq* has been increased, it stops the temperature rise control at timing θ1 and executes normal control. In this case, the control device 60 increases the field current Ifr from the pre-change field current Iffor to the first field current Ifm1.

[0106] 19, Lmtpa denotes a maximum efficiency line formed by a combination of d- and q-axis currents Idr and Iqr corresponding to minimum current maximum torque control (MTPA). Furthermore, LIfm1 denotes a first intermediate torque line, which is an equal torque line when the field current Ifr is the first field current Ifm1. LIfm2 denotes a second intermediate torque line, which is an equal torque line when the field current Ifr is the second field current Ifm2.

[0107] 19A , at timing θ1, the control device 60 controls the current operating point of the rotary electric machine 20 to a first intermediate operating point OPm1, which is the intersection of the first intermediate torque line LIfm1 and the maximum efficiency line Lmtpa. In this case, the control device 60 reduces the d-axis current Idr from the pre-change d-axis current Idfor to the first d-axis current Idm1. In addition, the control device 60 reduces the q-axis current Iqr from the pre-change q-axis current Iqfor to the first q-axis current Iqm1.

[0108] The control device 60 changes the generated torque Trqr from the pre-change torque Tfor to the post-change torque Tlat at timing θ2 in Fig. 18. In this case, the control device 60 increases the field current Ifr from the first field current Ifm1 to the second field current Ifm2.

[0109] 19B , at timing θ2, the control device 60 controls the current operation point to a second intermediate operating point OPm2, which is the intersection of the second intermediate torque line LIfm2 and the maximum efficiency line Lmtpa. In this case, the control device 60 reduces the d-axis current Idr from the first d-axis current Idm1 to the second d-axis current Idm2. The control device 60 also reduces the q-axis current Iqr from the first q-axis current Iqm1 to the second q-axis current Iqm2.

[0110] The control device 60 resumes the temperature increase control in the low flux mode at timing θ3 in Fig. 18. In this case, the control device 60 reduces the field current Ifr from the second field current Ifm2 to the changed field current Iflat.

[0111] 19C, the control device 60 controls the current operating point to the changed operating point OPlat at timing θ3. In this case, the control device 60 reduces the d-axis current Idr from the second d-axis current Idm2 to the changed d-axis current Idlat. Also, the control device 60 increases the q-axis current Iqr from the second q-axis current Iqm2 to the changed q-axis current Iqlat.

[0112] Here, the following are all smaller than the decrease from the pre-change d-axis current Idfor to the post-change d-axis current Idlat (= Idfor - Idlat): the decrease from the pre-change d-axis current Idfor to the first d-axis current Idm1 (= Idfor - Idm1), the decrease from the first d-axis current Idm1 to the second d-axis current Idm2 (= Idm1 - Idm2), and the decrease from the second d-axis current Idm2 to the post-change d-axis current Idlat (= Idm2 - Idlat). Therefore, the occurrence of torque shock can be suppressed compared to when the generated torque Trqr is increased while executing the low magnetic flux mode.

[0113] As described above, when the generated torque Trqr fluctuates, the temperature increase control in the low magnetic flux mode is paused, thereby making it possible to suppress the occurrence of torque shock.

[0114] <Modification of the Fourth Embodiment> When at least one of the field current Ifr and the d- and q-axis currents Idr and Iqr is changed, at least one of the field current Ifr and the d- and q-axis currents Idr and Iqr may be changed gradually. Specifically, for example, when increasing the field current Ifr from the pre-change field current Iffor to the first field current Ifm1, the control device 60 may gradually increase the field target current If*. This makes it possible to suppress the occurrence of torque shock.

[0115] Fifth Embodiment A fifth embodiment will be described below with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, as shown in Fig. 20, the rotating electrical machine 20 is a memory motor.

[0116] The rotor 21 of the rotating electric machine 20 has permanent magnets 25 (e.g., neodymium magnets) as field poles instead of the field winding 22 of the first embodiment. Therefore, the system of this embodiment does not have a field current supply circuit 40 or a field current sensor 52.

[0117] Next, an outline of the temperature rise control of this embodiment will be described.

[0118] The torque Trqr generated by the permanent magnet field type rotating electric machine 20 is made up of a magnet torque TM and a reluctance torque TR, as expressed by the following equation (eq4): In the following equation (eq4), φmr represents the magnetic flux generated by the permanent magnet 25.

[0119] Trqr=TM+TR =P・φmr・Iqr+P・(Ld−Lq)・Idr・Iqr…(eq4)

[0120] In this embodiment, the low flux mode shown in Fig. 9 is executed. In step S40, the control device 60 controls the generated torque Trqr to the command torque Trq* while imposing conditions that the magnitude of the current vector is made equivalent to that in the high flux mode and the current advance angle θr is made smaller than that in the high flux mode, thereby reducing the magnetic flux φm. In this case, the magnetic flux φm is reduced by flowing field-weakening currents that demagnetize the permanent magnet 25 through the U-, V-, and W-phase windings 24U, 24V, and 24W.

[0121] According to this embodiment, the same effects as those of the first embodiment can be obtained.

[0122] Other Embodiments The above-described embodiments may be modified as follows.

[0123] The low magnetic flux mode described in the second to fourth embodiments may be applied to the fifth embodiment.

[0124] The target to be heated by the temperature rise control may be, for example, the coolant in the circulation path 200. If the vehicle is equipped with an air conditioning system that uses the coolant as a heat source for heating the passenger compartment, the temperature of the heating heat source can be quickly raised by the temperature rise control. In this case, the upper control device 80 may input a temperature rise command to the control device 60 when, for example, it determines that the detected value of the coolant temperature sensor 57 is lower than the target temperature.

[0125] The rotating electric machine 20 may have a reverse saliency characteristic in which the d-axis inductance Ld is smaller than the q-axis inductance Lq. Furthermore, the rotating electric machine 20 is not limited to a salient-pole machine, and may be a non-saliency-pole machine in which the q-axis inductance Lq and the d-axis inductance Ld are equal (Lq = Ld). In this case, the control device 60 calculates the q-axis target current Iq* based on the following equation (eq5) in step S33 of FIG. 8 and step S41 of FIG. 9 .

[0126] Trqr=P・φfr・Iqr…(eq5)

[0127] The rotating electric machine is not limited to a synchronous machine, and may be an asynchronous machine such as an induction machine.

[0128] The rotating electric machine is not limited to a radial type in which the rotor and the stator face each other in the radial direction, but may be an axial type in which the rotor and the stator face each other in the axial direction of the rotating shaft.

[0129] The rotating electric machine is not limited to a star-connected one, but may be a delta-connected one.Furthermore, the rotating electric machine and the inverter are not limited to a three-phase one, but may be a two-phase one, or a four-phase or more phase one.

[0130] The heat transfer unit is not limited to a unit that uses cooling water as a cooling fluid, but may be, for example, an air-cooled unit that uses gas (air) as a cooling fluid, or a metal heat sink. When a heat sink is used as the heat transfer unit, for example, it is sufficient that a power converter such as an inverter and a storage battery are provided on the heat sink.

[0131] The inverter switches are not limited to N-channel MOSFETs, but may be IGBTs, for example. In this case, it is sufficient that a freewheel diode is connected in reverse parallel to the IGBT.

[0132] The power storage unit connected to a power converter such as an inverter is not limited to a storage battery. For example, it may be a large-capacity electric double layer capacitor, or a unit including both a storage battery and an electric double layer capacitor.

[0133] The mobile body on which the control device is mounted is not limited to a vehicle, but may be, for example, an aircraft or a ship. The control device is also not limited to a mobile body, but may be a stationary device.

[0134] The control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method described herein may be implemented by one or more special-purpose computers configured by combining a processor and memory programmed to perform one or more functions with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory tangible storage medium.

[0135] The following describes characteristic configurations extracted from the above-described embodiments. [Configuration 1] A control device (60) for a power converter applied to a system including: a power storage unit (10), a rotating electric machine (20) having a multi-phase armature winding (24U-24W) and a rotor (21), and a power converter (30) electrically connecting the power storage unit and the armature winding and having upper and lower arm switches (SUH-SWL), the control device (60) comprising: a determination unit (100) that determines whether or not there is a temperature increase request for the temperature increase target unit (10), and a switch control unit (101) that, when it is determined that there is the temperature increase request, performs temperature increase control to increase the magnitude of a current vector flowing in the armature winding compared to when it is determined that there is no temperature increase request, and performs switching control of the upper and lower arm switches to control the torque generated by the rotating electric machine to a command torque (Trq*), The control device for a power converter according to Configuration 1, wherein the switch control unit performs a ripple suppression process to reduce the magnetic flux of the rotor so as to reduce the magnitude of an angle formed between a q-axis of a dq coordinate system and a current vector flowing through the armature winding when the temperature rise control determines that the torque ripple of the rotating electric machine is greater than a threshold value. [Configuration 2] The power converter is a first power converter, the rotating electric machine has a field winding (22), and the system includes a second power converter (40) that electrically connects the power storage unit and the field winding, and the switch control unit performs switching control of the second power converter to control a field current flowing through the field winding, and the ripple suppression process involves reducing the magnetic flux of the rotor by reducing the field current flowing through the field winding. [Configuration 3] The control device for a power converter according to Configuration 1, wherein the rotating electric machine is a memory motor including the rotor having a permanent magnet, and the switch control unit performs the ripple suppression process by flowing a field-weakening current that demagnetizes the permanent magnet through the armature winding, thereby reducing the magnetic flux of the rotor.[Configuration 4] The control device for a power converter according to any one of configurations 1 to 3, wherein the switch control unit switches between a first mode and a second mode as the ripple suppression process based on a request state in the temperature rise control, and reduces the magnetic flux of the rotor in the first mode compared to the magnetic flux of the rotor in the second mode. [Configuration 5] The control device for a power converter according to any one of configurations 1 to 3, wherein the switch control unit switches between the first mode and the second mode as the ripple suppression process based on a temperature of the rotating electric machine, and reduces the magnetic flux of the rotor in the first mode compared to the magnetic flux of the rotor in the second mode. [Configuration 6] The control device for a power converter according to any one of configurations 1 to 5, wherein, when it is determined that the command torque will change by more than a predetermined amount during execution of the temperature rise control, the switch control unit changes the torque generated by the rotating electric machine by the predetermined amount while stopping the temperature rise control, and then resumes the temperature rise control. [Configuration 7] The control device for a power converter according to any one of Configurations 1 to 6, wherein the switch control unit adds an AC signal to at least one of a d-axis target current and a q-axis target current, which are target values ​​of current to be passed through the armature winding, in order to reduce torque ripple of the rotating electric machine during the temperature rise control.

[0136] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and equivalent modifications. In addition, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

Claims

1. A control device (60) for a power converter applied to a system including: a power storage unit (10); a rotating electric machine (20) having a multi-phase armature winding (24U-24W) and a rotor (21); and a power converter (30) electrically connecting the power storage unit and the armature winding and having upper and lower arm switches (SUH-SWL), the control device (60) comprising: a determination unit (100) that determines whether or not there is a temperature increase request for the temperature increase target unit (10); and a switch control unit (101) that, when it is determined that there is a temperature increase request, performs temperature increase control to increase the magnitude of a current vector flowing in the armature winding compared to when it is determined that there is no temperature increase request, and performs switching control of the upper and lower arm switches to control the torque generated by the rotating electric machine to a command torque (Trq*), When the switch control unit determines that the torque ripple of the rotating electric machine is greater than a threshold value during the temperature rise control, the switch control unit performs a ripple suppression process to reduce the magnetic flux of the rotor in order to reduce the angle between the q-axis of a dq coordinate system and the current vector flowing through the armature winding.

2. The control device for a power converter according to claim 1, wherein the power converter is a first power converter, the rotating electric machine has a field winding (22), the system includes a second power converter (40) that electrically connects the power storage unit and the field winding, and the switch control unit performs switching control of the second power converter to control the field current flowing in the field winding, and performs processing to reduce the magnetic flux of the rotor by reducing the field current flowing in the field winding as the ripple suppression processing.

3. The control device for a power converter according to claim 1, wherein the rotating electric machine is a memory motor equipped with a rotor having a permanent magnet, and the switch control unit performs the ripple suppression process by passing a field-weakening current that demagnetizes the permanent magnet through the armature winding, thereby reducing the magnetic flux of the rotor.

4. The control device for a power converter according to claim 2 or 3, wherein the switch control unit switches between a first mode and a second mode as the ripple suppression process based on a required state in the temperature rise control, and makes the magnetic flux of the rotor in the first mode smaller than the magnetic flux of the rotor in the second mode.

5. A control device for a power converter as described in claim 2 or 3, wherein the switch control unit switches between a first mode and a second mode as the ripple suppression process based on the temperature of the rotating electric machine, and makes the magnetic flux of the rotor in the first mode smaller than the magnetic flux of the rotor in the second mode.

6. A control device for a power converter as described in claim 2 or 3, wherein, when the switch control unit determines that the command torque will change by more than a predetermined amount while the temperature rise control is being executed, the switch control unit changes the torque generated by the rotating electric machine by the predetermined amount while stopping the temperature rise control, and then resumes the temperature rise control.

7. A control device for a power converter as claimed in any one of claims 1 to 3, wherein the switch control unit applies an AC signal to at least one of the d-axis target current and the q-axis target current, which are target values ​​of the current to be passed through the armature winding, in order to reduce the torque ripple of the rotating electric machine during the temperature rise control.

8. A program applied to a system including: a power storage unit (10); a rotating electric machine (20) having a multi-phase armature winding (24U-24W) and a rotor (21); and a power converter (30) electrically connecting the power storage unit and the armature winding and having upper and lower arm switches (SUH-SWL), the program executing: a determination process for determining whether or not there is a temperature increase request for the temperature increase target unit (10); and a control process for, when it is determined that there is a temperature increase request, performing temperature increase control to increase the magnitude of the current vector flowing in the armature winding compared to when it is determined that there is no temperature increase request, and performing switching control of the upper and lower arm switches to control the torque generated by the rotating electric machine to a command torque (Trq*), A program that, if it is determined that the torque ripple of the rotating electric machine is larger than a threshold value during the temperature rise control in the control processing, performs a ripple suppression processing that reduces the magnetic flux of the rotor in order to reduce the angle between the q-axis of a dq coordinate system and the current vector flowing through the armature winding.

9. A control method for a power converter applied to a system including: a power storage unit (10); a rotating electric machine (20) having a multi-phase armature winding (24U to 24W) and a rotor (21); and a power converter (30) electrically connecting the power storage unit and the armature winding and having upper and lower arm switches (SUH to SWL), the control method comprising: a determination step of determining whether or not there is a temperature increase request for the temperature increase target unit (10); and a control step of, when it is determined that there is a temperature increase request, performing temperature increase control to increase the magnitude of the current vector flowing in the armature winding compared to when it is determined that there is no temperature increase request, and performing switching control of the upper and lower arm switches to control the torque generated by the rotating electric machine to a command torque (Trq*), A control method for a power converter, wherein, if it is determined in the temperature rise control in the control step that the torque ripple of the rotating electric machine is larger than a threshold value, a ripple suppression process is performed to reduce the magnetic flux of the rotor so as to reduce the magnitude of the angle between the q-axis of a dq coordinate system and the current vector flowing through the armature winding.

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