Control device for power converter and program

Abstract

A control device (60) is applied to a system comprising a pair of gears (13, 14) constituting a motive power transmission mechanism (11) from a rotor (31) of a rotary electric machine (30) to a rotary drive target (12). The control device comprises: target value calculation units (63, 67, 163) that calculate d- and q-axis target currents (Id*, Iq*) to be passed in armature windings (34U to 34W); and an armature control unit (68) that performs switching control on a power converter (20) so as to control the d-axis current (Idr) flowing in a corresponding armature winding to be set to the d-axis target current and so as to control the q-axis current (Iqr) flowing in a corresponding armature winding to be set to the q-axis target current. The target value calculation unit calculates d- and q-axis target currents so as to satisfy a first condition in which a generated torque of the rotor is set to a torque capable of maintaining the rotation stop state of the rotor, and a second condition in which a time average value of the generated torque in one cycle or a plurality of cycles of an AC current flowing in the armature windings is offset from 0.

Description

Power converter control device and program CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2023-097686 filed on June 14, 2023, the contents of which are incorporated herein by reference.

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

[0003] A conventional system includes a power storage unit, a power converter electrically connected to the power storage unit, and a rotating electric machine having an armature winding electrically connected to the power converter. A control device applied to this system performs switching control of the power converter to zero the q-axis current flowing through the armature winding while causing a d-axis current to flow through the armature winding. This increases the temperature of the power storage unit while maintaining a stopped state of the rotor of the rotating electric machine. An example of such a control device is the control device disclosed in Patent Document 1.

[0004] Patent No. 5259752

[0005] When heat is generated by switching control of the power converter while the rotor is kept stopped, noise and vibration (NV) can become a problem.

[0006] The main object of the present disclosure is to provide a control device and program for a power converter that can improve noise and vibration when heat is generated by switching control of the power converter while maintaining a stopped state of rotation of the rotor of a rotating electric machine.

[0007] The present disclosure relates to a control device for a power converter that is applied to a system including: a power storage unit; a rotating electric machine having a rotor and an armature winding; a power converter that electrically connects the power storage unit and the armature winding and has upper and lower arm switches; and at least a pair of gears that constitute a power transmission mechanism from the rotor to a rotationally driven object, rotated by rotational power from the rotor and meshing with each other, the control device comprising: a target value calculation unit that calculates d- and q-axis target currents to be passed through the armature winding; and an armature control unit that performs switching control of the upper and lower arm switches to control the d-axis current flowing through the armature winding to the calculated d-axis target current, and to control the q-axis current flowing through the armature winding to the calculated q-axis target current, The target value calculation unit calculates the d- and q-axis target currents so as to satisfy a first condition that the torque generated by the rotor is a torque that can maintain the rotor in a stopped state, and a second condition that the time average value of the generated torque over one cycle or multiple cycles of the AC current flowing through the armature winding is offset from zero.

[0008] In the present disclosure, switching control of upper and lower arm switches constituting a power converter is performed to control the d-axis current flowing through the armature winding to a d-axis target current and to control the q-axis current flowing through the armature winding to a q-axis target current. The d- and q-axis target currents are calculated so as to satisfy the condition that the torque generated by the rotor is a torque that can maintain the rotor in a stopped state.

[0009] In the present disclosure, the system includes at least a pair of gears that constitute a power transmission path from the rotor to a rotationally driven object. The pair of gears mesh with each other and are rotated by the rotational power from the rotor.

[0010] Here, the pair of gears has backlash. When the polarity of the torque generated by the rotor alternates between positive and negative due to the switching control, the direction of rotation of the gears alternates, which can cause gear rattle. In this case, gear rattle noise occurs even though the rotor remains stopped. If the gear rattle noise becomes louder, the noise level of the system will deteriorate.

[0011] Therefore, in the present disclosure, the d- and q-axis target currents are calculated so as to satisfy the condition that the time average value of the torque generated by the rotating electric machine in one or more cycles of the AC current flowing through the armature winding is offset from 0. This makes it possible to maintain the pressing state between the teeth of the pair of gears and suppress the occurrence of gear rattle, or to reduce the gear rattle even if it does occur. As a result, noise immunity can be improved.

[0012] 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 an on-board system according to a first embodiment, Fig. 2 is a diagram showing an overview of a cooling system as a heat transfer unit, Fig. 3 is a diagram showing gear tooth rattle according to a comparative example, Fig. 4 is a time chart showing a schematic diagram of the transition of torque generated by a rotor according to a comparative example, Fig. 5 is a time chart showing a schematic diagram of the transition of torque generated by a rotor according to the first embodiment, Fig. 6 is a diagram showing a mode in which gear tooth rattle is prevented, Fig. 7 is a time chart showing a transition of rotor rotation angle during temperature rise control according to the first embodiment and the comparative example, Fig. 8 is a time chart showing the transition of three-phase AC current, d-axis and q-axis currents, and field current during temperature rise control, Fig. 9 is a block diagram of temperature rise control, Fig. 10 is a flowchart showing the processing procedure of temperature rise control, and Fig. 11 is a diagram showing the processing procedure of temperature rise control. FIG. 12 is a time chart showing the gradual change processing mode according to the second embodiment, FIG. 13 is a block diagram of an initial target value calculation unit, FIG. 14 is a block diagram of an end target value calculation unit, FIG. 15 is an overall configuration diagram of an in-vehicle system according to a third embodiment, FIG. 16 is a time chart showing the progression of d- and q-axis target currents, FIG. 17 is a time chart showing the progression of d- and q-axis target currents, FIG. 18 is a block diagram of temperature rise control, FIG. 19 is a flowchart showing the processing procedure for temperature rise control, FIG. 20 is a time chart showing the progression of d- and q-axis target currents according to the fourth embodiment, FIG. 21 is a time chart schematically showing the progression of torque generated by a rotor according to another embodiment, and FIG. 22 is a time chart schematically showing the progression of torque generated by a rotor according to another embodiment.

[0013] 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.

[0014] 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 30. In this embodiment, the rotating electric machine 30 is a wound-field rotating electric machine. The rotating electric machine 30 in this embodiment is a rotating electric machine having forward salient polarity, in which the d-axis inductance Ld is larger than the q-axis inductance Lq.

[0015] The storage battery 10 is, for example, a battery pack including a series connection of unit cells. A unit cell is a single battery cell or a series connection of multiple battery cells. The battery cells are, for example, secondary batteries such as lithium-ion batteries. The storage battery 10 can be charged by an external charger provided outside the vehicle. The external charger is, for example, a stationary charger.

[0016] The rotating electric machine 30 is a device that applies rotational power to the drive wheels 12 (corresponding to "rotationally driven objects") of the vehicle to rotate the drive wheels 12. The rotating electric machine 30 includes a rotor 31. The rotor 31 includes a rotor core and a plurality of field salient poles extending radially from the rotor core. A field winding 32 is wound around each field salient pole. The rotating shaft of the rotor 31 is capable of transmitting power to the drive wheels 12 of the vehicle via a power transmission mechanism 11 provided in the system. Torque generated by the rotating electric machine 30 functioning 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 rotating electric machine 30 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.

[0017] The power transmission mechanism 11 includes a transmission and a shaft. The transmission is, for example, a reduction gear and includes at least a pair of gears (see FIGS. 3 and 6 ). More specifically, the transmission includes a first gear 13 and a second gear 14. The first gear 13 and the second gear 14 are meshed with each other and are rotatable about a central axis of rotation extending in a predetermined direction.

[0018] The rotating electric machine 30 includes a stator 33. The stator 33 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 31. The armature winding includes U-, V-, and W-phase windings 34U, 34V, and 34W that are star-connected with a 120° electrical angle offset from one another.

[0019] The system includes an inverter 20 (corresponding to a "first power converter") and a field energization circuit 40 (corresponding to a "second power converter"). The inverter 20 converts DC current from the storage battery 10 into AC current and supplies it to an armature winding. The inverter 20 includes a series-connection 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.

[0020] 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 20 includes a first capacitor 21, which is a smoothing capacitor. The first capacitor 21 may be provided outside the inverter 20.

[0021] The field energization circuit 40 supplies current from the storage battery 10 to the field winding 32. 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.

[0022] 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 32 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 32 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 energization circuit 40 and the first capacitor 21 is provided individually in the inverter 20, a configuration in which a common capacitor is provided in the inverter 20 and the field energization circuit 40 may be adopted. In this case, for example, the second capacitor 41 may not be provided.

[0023] As shown in FIG. 2 , the system includes a device for cooling the inverter 20, the field energization circuit 40, the rotating electric machine 30, and the storage battery 10 when switching control of the inverter 20 is being performed to run the vehicle. Specifically, the vehicle includes a circulation path 400 through which coolant circulates, an electric water pump 401, a radiator 402, and an electric fan 403. The water pump 401 is powered and driven to circulate the coolant. In the example shown in FIG. 2 , the inverter 20, the field energization circuit 40, the rotating electric machine 30, and the storage battery 10 are arranged in this order downstream of the water pump 401 in the circulation path 400. Note that the arrangement order of the components in the circulation path 400 is not limited to the order shown in FIG. 2 .

[0024] A radiator 402 is provided in circulation path 400 between water pump 401 and storage battery 10. Radiator 402 cools the coolant flowing in through circulation path 400 and supplies the cooled coolant to water pump 401. The coolant flowing into radiator 402 is cooled by wind blown against radiator 402 as the vehicle travels and wind blown against radiator 402 by rotating fan 403.

[0025] The water pump 401 and the fan 403 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 401 and the fan 403 are driven by the control device 60 provided in the system.

[0026] Returning to the explanation 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, and a coolant temperature sensor 55. The voltage sensor 50 detects the voltage of the storage battery 10. The phase current sensor 51 detects phase currents flowing in at least two of the U-, V-, and W-phase windings 34U, 34V, and 34W. The field current sensor 52 detects the field current flowing in the field winding 32. The angle sensor 53 detects the rotation angle (specifically, the electrical angle) of the rotor 31. The battery temperature sensor 54 detects the temperature of the storage battery 10. The coolant temperature sensor 55 detects the temperature of the coolant flowing in the circulation path 400.

[0027] 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 55 are input to the control device 60.

[0028] The control device 60 is an electronic control unit mainly composed of a microcomputer 60a. The upper control device 80 is an electronic control unit mainly composed of a microcomputer. The control device 60 and the upper control device 80 are capable of exchanging information.

[0029] The microcomputer 60a includes a CPU (Central Processing Unit). The functions provided by the microcomputer 60a can be provided by software stored in a physical memory device and a computer executing the software, software alone, hardware alone, or a combination thereof. For example, if the microcomputer 60a is provided by a hardware electronic circuit, the function can be provided by a digital circuit including multiple logic circuits or an analog circuit. For example, the microcomputer 60a executes a program stored on a non-transitory tangible storage medium serving as its own storage unit. The program includes, for example, programs for the processes shown in Figures 9 to 11 (described below). A method corresponding to the program is executed by executing a set of instructions constituting the program. The storage unit is, for example, a non-volatile memory. The program stored in the storage unit can be updated via a communication network such as the Internet, for example, via OTA (Over the Air).

[0030] The control device 60 performs switching control of each switch constituting the field energization circuit 40 to excite the field winding 32. 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.

[0031] While the field winding 32 is excited, the control device 60 performs switching control of each switch constituting the inverter 20 based on the detection values ​​of the sensors 50 to 55 to feedback control the control variable of the rotating electric machine 30 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. Through this feedback control, the rotational power of the rotor 31 is transmitted to the drive wheels 12, causing the vehicle to run.

[0032] Next, the temperature rise control of the storage battery 10 executed by the control device 60 will be described. This control generates heat by controlling the switching of the inverter 20 and the field current circuit 40 when the temperature Tr of the storage battery 10 detected by the battery temperature sensor 54 falls below the target temperature T* while the storage battery 10 is being charged by an external charger while the vehicle is parked. The generated heat is transferred to the storage battery 10 via the coolant circulating through the circulation path 400 by driving the water pump 401. The temperature rise control continues, for example, until the temperature Tr of the storage battery 10 reaches the target temperature T*. The water pump 401 continues to be driven at least while the temperature rise control is being executed. In this embodiment, the circulation path 400, the coolant circulating through the circulation path 400, and the water pump 401 correspond to a "heat transfer unit." The temperature rise control quickly raises the temperature of the storage battery 10, thereby shortening the charging time of the storage battery 10 using an external charger.

[0033] In order to increase the temperature rise capability of the temperature rise control, the control device 60 performs switching control of the inverter 20 so that sinusoidal d- and q-axis currents flow through the armature windings during the temperature rise control. At this time, in order to maintain the rotor 31 in a stopped state and to keep the vehicle stationary, the control device 60 performs switching control of the field energization circuit 40 so that the reluctance torque generated by the flow of the d- and q-axis currents is reduced by the magnet torque.

[0034] As shown in FIG. 3 , the first gear 13 and the second gear 14 constituting the power transmission mechanism 11 have backlash. FIG. 3 illustrates an example of external gears as the gears 13 and 14. In a configuration with backlash, when the polarity of the torque Trqr generated by the rotor 31 alternates between positive and negative as shown in FIG. 4 due to switching control of the inverter 20 during temperature rise control, the rotation direction of the first gear 13 and the second gear 14 alternates, potentially resulting in tooth strike, in which the teeth 13 a of the first gear 13 and the teeth 14 a of the second gear 14 collide with each other. Trqmax in FIG. 4 is a torque threshold. The torque threshold Trqmax is the torque at which the drive wheels 12 begin to rotate, and is set, for example, to the upper limit of an expected range of torque at which the drive wheels 12 begin to rotate. Note that TrH and TrL in FIG. 4 are upper and lower limit values ​​that define a torque range ΔTr that keeps noise and vibration characteristics (e.g., noise and vibration) generated during temperature rise control below an allowable value.

[0035] During temperature rise control, even though the torque Trqr generated by the rotor 31 is equal to or less than the torque threshold value Trqmax and the rotor 31 is maintained in a stopped state, if the gear rattle noise increases, the noise and vibration of the system will deteriorate.

[0036] Incidentally, it is also conceivable to perform temperature increase control so as to set the generated torque Trqr to 0. However, even if the amount of fluctuation in the actual generated torque is small, there is a concern that the polarity of the generated torque may alternate between positive and negative due to detection errors of the phase current sensor 51, resulting in gear strike.

[0037] Therefore, in this embodiment, as shown in Figures 5 and 8, switching control of the inverter 20 and the field energization circuit 40 is performed so as to satisfy the condition that the time average value of the generated torque Trqr in one cycle or multiple cycles of the AC current flowing through the armature winding is offset from 0 by an offset value Toffset. As a result, as shown in Figures 6 and 7, the teeth 13a of the first gear 13 and the teeth 14a of the second gear 14 are maintained in a pressed state against each other, suppressing the occurrence of rattle noise and improving NV.

[0038] Next, an outline of the temperature rise control of this embodiment will be described.

[0039] The torque Trq generated by the wound-field rotating electric machine 30 is composed of a magnet torque TM and a reluctance torque TR, as expressed by the following equation (eq1): In the following equation (eq1), P represents the number of pole pairs of the rotating electric machine 30, and φf represents the magnetic flux generated by the field current flowing through the field winding 32.

[0040] Trq = TM + TR = P φf Iq + P (Ld - Lq) Id Iq (eq1) During temperature rise control, control device 60 controls the switching of inverter 20 so that sinusoidal three-phase AC currents IU, IV, IW, which are shifted in phase by 120 electrical degrees, flow through windings 34U to 34W. In this case, sinusoidal d- and q-axis currents Id, Iq flow. In this case, the d- and q-axis currents Id, Iq have the same frequency, and the phase difference between d-axis current Id and q-axis current Iq is 90 electrical degrees.

[0041] Here, in order to satisfy the condition that the time average value of the generated torque Trqr in one cycle of the AC current flowing through the armature winding is always offset from 0 by the offset value Toffset, the left side of the above equation (eq1) is replaced with the offset value Toffset, thereby deriving the following equation (eq2): The offset value Toffset is set to a value such that the generated torque of the rotor 31 is equal to or less than the torque threshold value Trqmax.

[0042] Toffset=P·φf·Iq+P·(Ld−Lq)·Id·Iq (eq2) Also, there is the relationship "φf=Lmf×If", where Lmf (>0) is the coupling inductance, and is the inductance of the d-axis magnetic path including the back yoke portion and teeth portion of the stator 33 and the rotor core and field salient pole portion of the rotor 31.

[0043] Substituting "φf=Lmf×If" into the above equation (eq2) and solving the above equation (eq2) for the d-axis current Id, the following equation (eq3) is derived.

[0044] As shown in Fig. 8, the control device 60 calculates a sinusoidal field target current If*. The control device 60 also calculates a sinusoidal q-axis target current Iq* that has a phase difference of 90 degrees from the field target current If*. The control device 60 calculates a d-axis target current Id* based on the calculated field target current If* and q-axis target current Iq* and the above equation (eq3). The target currents If*, Iq*, and Id* have the same frequency, and the phase difference between the d-axis target current Id* and the field target current If* is 180 degrees.

[0045] The polarity of the second term on the right side of equation (eq3) above, which includes the offset value Toffset, changes every time the polarity of the q-axis target current Iq* changes. In Fig. 8 , t1 is the timing when the polarity of the q-axis target current Iq* changes from positive to negative, and t2 is the timing when the polarity of the q-axis target current Iq* changes from negative to positive. When the polarity of the q-axis target current Iq* changes, the d-axis target current Id* has a waveform such that the magnitude of the d-axis target current Id* is offset in the increasing direction.

[0046] FIG. 9 shows a block diagram of the temperature increase control executed by the control device 60.

[0047] The three-phase target amplitude calculation unit 61 acquires the target heat quantity Q* from the higher-level control device 80 for each control period, and calculates the amplitude Iuamp* of the U-phase target current, the amplitude Ivamp* of the V-phase target current, and the amplitude Iwamp* of the W-phase target current based on the acquired target heat quantity Q*. The amplitudes Iuamp*, Ivamp*, and Iwamp* have the same value. For example, the three-phase target amplitude calculation unit 61 calculates larger amplitudes Iuamp*, Ivamp*, and Iwamp* as the target heat quantity Q* increases. The three-phase target amplitude calculation unit 61 may calculate the amplitudes Iuamp*, Ivamp*, and Iwamp* based on, for example, map information correlating the target heat quantity Q* with the amplitudes Iuamp*, Ivamp*, and Iwamp*, and the acquired target heat quantity Q*. The target heat quantity Q* is, for example, a target value of the heat quantity [W] generated per unit time at each switch SUH, SUL, SVH, SVL, SWH, and SWL in conjunction with the switching control of each switch SUH, SUL, SVH, SVL, SWH, and SWL of the inverter 20.

[0048] The two-phase target amplitude calculation unit 62 converts the amplitudes Iuamp*, Ivamp*, Iwamp* of the currents of each phase in the three-phase fixed coordinate system into the amplitude Idamp* of the d-axis target current Id* and the amplitude Iqamp* of the q-axis target current Iq* in the two-phase rotating coordinate system (dq coordinate system) based on the amplitudes Iuamp*, Ivamp*, Iwamp* of the currents of each phase and the electrical angle θe detected by the angle sensor 53 for each control period.

[0049] The target q-axis current calculation unit 63 calculates a sinusoidal q-axis target current Iq* having an amplitude Iqamp* of the q-axis target current Iq* calculated by the two-phase target amplitude calculation unit 62. The target q-axis current calculation unit 63 calculates the q-axis target current Iq*, for example, using the following equation (eq4): In the following equation (eq4), ω represents each frequency, and t represents the elapsed time from the reference timing.

[0050] Iq* = Iqamp* × sin(ω × t)... (eq4) The two-phase conversion unit 64 converts the U, V, and W phase currents in the three-phase fixed coordinate system into a d-axis current Idr and a q-axis current Iqr in the dq coordinate system based on the detection value of the phase current sensor 51 and the detected electrical angle θe for each control period.

[0051] The target field calculation unit 65 calculates, for each control period, a sinusoidal field target current If* that is shifted in phase by 90 degrees from the q-axis target current Iq* and has the same frequency as the q-axis target current Iq*, based on the amplitude Idamp* of the d-axis target current Id* calculated by the two-phase target amplitude calculation unit 62. The target field calculation unit 65 calculates the field target current If*, for example, based on the amplitude Idamp* of the d-axis target current Id* and the following equation (eq5):

[0052] The frequency of the field target current If* is set to a frequency that satisfies the control response of the field current Ifr, for example, a frequency of 5 Hz or more or 10 Hz or more and 30 or 40 Hz or less.

[0053] The field control unit 66 generates gate drive signals for the switches SH1, SL1, SH2, and SL2 of the field energization circuit 40 in order to feedback control the detected field current Ifr to the field target current If* calculated by the target field calculation unit 65. The field control unit 66 outputs the generated gate drive signals to drive circuits that drive the switches SH1, SL1, SH2, and SL2. This controls the field current Ifr to the sinusoidal field target current If*.

[0054] The target d-axis current calculation unit 67 calculates the d-axis target current Id* for each control period based on the field target current If* calculated by the target field calculation unit 65, the q-axis target current Iq* calculated by the target q-axis current calculation unit 63, and the above equation (eq3). In this embodiment, since "Ld>Lq", the phase difference between the d-axis target current Id* and the field target current If* is 180 degrees. In this embodiment, the target d-axis current calculation unit 67 and the target q-axis current calculation unit 63 correspond to a "target value calculation unit."

[0055] Incidentally, if the denominator of the second term on the right side of equation (eq3) approaches zero, the d-axis target current Id* may become very large. In this embodiment, the d-axis target current Id* is calculated so as not to become very large. For example, the target d-axis current calculation unit 67 includes a limiter. If the absolute value of the second term on the right side exceeds a limit value, the limiter sets the absolute value of the second term on the right side as the limit value. If Ip is the maximum value within the range of the peak value of the d-axis target current Id*, the limit value may be set to, for example, "0.05 × Ip ≦ limit value ≦ 0.25 × Ip," "0.1 × Ip ≦ limit value ≦ 0.2 × Ip," "0.05 × Ip ≦ limit value ≦ 0.15 × Ip," or "0.08 × Ip ≦ limit value ≦ 0.12 × Ip." Note that even if the target d-axis current calculation unit 67 does not include a limiter, no control problems occur. For example, even if the denominator of the second term on the right side becomes close to 0 and the d-axis target current Id* becomes a very large value, the actual d-axis current will not become a very large value due to the influence of the responsiveness of the actual d-axis current.

[0056] The three-phase control unit 68 functions as an "armature control unit" that generates gate drive signals for the switches SUH, SUL, SVH, SVL, SWH, and SWL of the inverter 20 to feedback-control the q-axis current Iqr calculated by the two-phase conversion unit 64 to the calculated q-axis target current Iq*, and to feedback-control the d-axis current Idr calculated by the two-phase conversion unit 64 to the d-axis target current Id* calculated by the target d-axis current calculation unit 67. This generation process uses the electrical angle θe and the power supply Vdc detected by the voltage sensor 50. The three-phase control unit 68 outputs the generated gate drive signals to drive circuits that drive the switches SUH, SUL, SVH, SVL, SWH, and SWL. As a result, the d-axis current Idr is controlled to the sinusoidal d-axis target current Id*, and the q-axis current Iqr is controlled to the sinusoidal q-axis target current Iq*.

[0057] 10 is a flowchart showing the procedure of the temperature increase control executed by the control device 60. This process is executed, for example, when the control device 60 determines that charging of the storage battery 10 by an external charger has started.

[0058] In step S10, it is determined whether or not there is a request to increase the temperature of the storage battery 10. In this embodiment, it is determined that there is a request to increase the temperature of the storage battery 10 when the detected temperature Tr of the storage battery 10 is lower than the target temperature T*. In this embodiment, the process of step S10 corresponds to the "determination unit."

[0059] If it is determined in step S10 that there is a temperature increase request, the process proceeds to step S11, where a temperature increase control process is performed.

[0060] In step S12, it is determined whether the temperature Tobj of the object to be heated has reached the target temperature T*. In this embodiment, as described above, the object to be heated is the storage battery 10, and therefore the temperature Tobj of the object to be heated is the temperature Tr of the storage battery 10.

[0061] If it is determined in step S12 that the temperature Tr of the storage battery 10 is lower than the target temperature T*, the process of step S11 is continued. On the other hand, if it is determined that the temperature Tr of the storage battery 10 has reached the target temperature T*, the temperature rise control is stopped. Incidentally, during the execution of the temperature rise control, the rotational driving of the fan 403 may be stopped in order to suppress a decrease in the temperature of the cooling water in the circulation path 400.

[0062] The process of step S11 will be described with reference to FIG.

[0063] In step S20, the target heat quantity Q* is acquired from the upper control device 80. Note that the upper control device 80 may calculate the target heat quantity Q* to be larger, for example, as the value obtained by subtracting the temperature Tr of the storage battery 10 from the target temperature T* is larger.

[0064] In step S21, the three-phase target amplitude calculation unit 61 calculates the amplitude Iuamp* of the U-phase target current, the amplitude Ivamp* of the V-phase target current, and the amplitude Iwamp* of the W-phase target current based on the target heat quantity Q* obtained in step S20.

[0065] In step S22, the two-phase target amplitude calculation unit 62 calculates the amplitude Idamp* of the d-axis target current Id* and the amplitude Iqamp* of the q-axis target current Iq* based on the amplitudes Iuamp*, Ivamp*, Iwamp* of the phase currents calculated in step S21 and the electrical angle θe.

[0066] In step S23, the target q-axis current calculation unit 63 calculates the q-axis target current Iq* based on the amplitude Iqamp* of the q-axis target current Iq* calculated in step S22.

[0067] In step S24, the target field calculation unit 65 calculates the field target current If* based on the amplitude Idamp* of the d-axis target current Id* calculated in step S22.

[0068] In step S25, the target d-axis current calculation unit 67 calculates the d-axis target current Id* based on the field target current If* calculated in step S24 and the q-axis target current Iq* calculated in step S23.

[0069] In step S26, the two-phase conversion unit 64 calculates the d-axis current Idr and the q-axis current Iqr based on the detection value of the phase current sensor 51 and the electrical angle θe.

[0070] In step S27, the field control unit 66 performs switching control of each of SH1, SL1, SH2, and SL2 of the field energizing circuit 40 to feedback control the field current Ifr to the field target current If* calculated in step S24.

[0071] In step S28, the three-phase control unit 68 performs feedback control of the d-axis current Idr calculated in step S26 to the d-axis target current Id* calculated in step S25, and also performs switching control of each switch SUH, SUL, SVH, SVL, SWH, and SWL of the inverter 20 to feedback control the q-axis current Iqr calculated in step S26 to the q-axis target current Iq* calculated in step S23.

[0072] According to the present embodiment described above, the teeth 13a, 14a of the pair of gears 13, 14 can be kept pressed against each other, thereby suppressing the occurrence of gear rattle noise.

[0073] Modification of First Embodiment The rotating electric machine 30 may be a rotating electric machine having reverse salience, in which the q-axis inductance Lq is larger than the d-axis inductance Ld. In this case, the phase difference between the d-axis target current Id* and the field target current If* is 0 degrees.

[0074] The control device 60 can vary the torque threshold value Trqmax. For example, when the control device 60 determines that the parking brake of the vehicle is in an applied state, the control device 60 sets the torque threshold value Trqmax to a value greater than when the parking brake is not in an applied state.

[0075] The control device 60 may also have an acquisition unit that acquires the temperature of the road surface on which the vehicle is traveling, and may change the torque threshold value Trqmax based on the acquired road surface temperature. In this case, map information that associates the road surface temperature with the torque threshold value Trqmax may be used.

[0076] During the execution of the temperature increase control, the control device 60 may apply a braking torque to the wheels of the vehicle using a mechanical brake device provided in the vehicle.

[0077] Second Embodiment The second embodiment will be described below with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, as shown in FIGS. 12 and 13 , the control device 60 includes an initial target value calculation unit 69A. The initial target value calculation unit 69A calculates initial d- and q-axis target currents Kt×Id* and Kt×Iq* and an initial field target current Kt×If*. The initial d- and q-axis target currents Kt×Id* and Kt×Iq* are the d- and q-axis target currents Id* and Iq* used during a first predetermined period from timing t1 to timing t2 when the three-phase control unit 68 starts controlling the switching of the inverter 20 and the field control unit 66 starts controlling the switching of the field energization circuit 40. The initial field target current Kt×If* is the field target current If* used during the first predetermined period. The calculated initial d-axis and q-axis target currents Kt×Id* and Kt×Iq* are used in the three-phase control unit 68 , and the calculated initial field target current Kt×If* is used in the field control unit 66 .

[0078] The initial target value calculation unit 69A sets the coefficient Kt to 0 at the start timing t1 of the first predetermined period, gradually increases the coefficient Kt towards 1 from the start timing t1 towards the end timing t2 of the first predetermined period, and sets the coefficient Kt to 1 after the end timing t2. The q-axis target current Iq* to be multiplied by the coefficient Kt is calculated by the target q-axis current calculation unit 63, and the d-axis target current Id* to be multiplied by the coefficient Kt is calculated by the target d-axis current calculation unit 67. Furthermore, the field target current If* to be multiplied by the coefficient Kt is calculated by the target field calculation unit 65.

[0079] This makes it possible to suppress pulsation of the torque generated by the rotor 31 when the temperature rise control is started.

[0080] 12 and 14, the control device 60 also includes an end target value calculation unit 69B. The end target value calculation unit 69B calculates end d- and q-axis target currents Kt×Id* and Kt×Iq* and an end field target current Kt×If*. The end d- and q-axis target currents Kt×Id* and Kt×Iq* are the d- and q-axis target currents Id* and Iq* used during a second predetermined period from timing t3, which is before timing t4, of the switching control of the inverter 20 by the three-phase control unit 68 and the switching control of the field energization circuit 40 by the field control unit 66 to end timing t4. The end field target current Kt×If* is the field target current If* used during the second predetermined period. The calculated end d-axis and q-axis target currents Kt×Id* and Kt×Iq* are used in the three-phase control unit 68, and the calculated end field target current Kt×If* is used in the field control unit 66.

[0081] The end target value calculation unit 69B sets the coefficient Kt to 1 at start timing t3 of the second predetermined period, gradually decreases the coefficient Kt towards 0 from start timing t3 towards end timing t4 of the second predetermined period, and sets the coefficient Kt to 0 after end timing t4. The q-axis target current Iq* to be multiplied by the coefficient Kt is calculated by the target q-axis current calculation unit 63, and the d-axis target current Id* to be multiplied by the coefficient Kt is calculated by the target d-axis current calculation unit 67. In addition, the field target current If* to be multiplied by the coefficient Kt is calculated by the target field calculation unit 65.

[0082] This makes it possible to suppress pulsation of the torque generated by the rotor 31 when the temperature rise control is completed.

[0083] Third Embodiment A third embodiment will now be described with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, as shown in FIG. 15 , a rotating electric machine 30 is a permanent magnet field type rotating electric machine.

[0084] The rotor 31 of the rotating electrical machine 30 has permanent magnets 35 (e.g., neodymium magnets) as field poles instead of the field winding 32 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.

[0085] Next, an outline of the temperature rise control of this embodiment will be described.

[0086] The torque Trq generated by the permanent magnet field type rotating electric machine 30 is made up of a magnet torque TM and a reluctance torque TR, as expressed by the following equation (eq6): In the following equation (eq6), φm represents the magnetic flux generated by the permanent magnet 35.

[0087] Trq = TM + TR = P φm Iq + P (Ld - Lq) Id Iq (eq6) Here, in order to satisfy the condition that the time average value of the generated torque Trqr in one cycle or multiple cycles of the AC current flowing through the armature winding is offset from 0 by the offset value Toffset, if the left side of the above equation (eq6) is set to the offset value Toffset, the following equation (eq7) is derived.

[0088] Toffset=P·φm·Iq+P·(Ld−Lq)·Id·Iq (eq7) When the above equation (eq7) is solved for the q-axis current Iq, the following equation (eq8) is derived.

[0089] The control device 60 of this embodiment calculates the d-axis target current Id*, which is a DC current. The control device 60 calculates the q-axis target current Iq* based on the calculated d-axis target current Id* and the above equation (eq8), and therefore the q-axis target current Iq* is also a DC current. Here, some rotating electric machines 30 have the following characteristics (A) or (B), so the control device 60 calculates the d-axis and q-axis target currents Id* and Iq* according to each characteristic.

[0090] (A) Characteristics where φm+(Lq-Ld)×Id>0 In this case, the control device 60 calculates d- and q-axis target currents Id* and Iq* that have the same polarity, as shown in FIG. 16. In FIG. 16, a positive d-axis current indicates a strong field current, and a negative d-axis current indicates a weak field current, so the control device 60 calculates the strong field d-axis target current Id*. In this case, it is possible to suppress demagnetization of the permanent magnet 35 that occurs when a weak field current is passed through the armature winding. Note that the control device 60 may calculate a weak field d-axis target current Id* instead of calculating the strong field d-axis target current Id*.

[0091] (B) Characteristics where φm+(Lq-Ld)×Id<0 In this case, the control device 60 calculates d-axis and q-axis target currents Id* and Iq* that have opposite polarities, as shown in Fig. 17. In the example shown in Fig. 17, the control device 60 calculates the d-axis target current Id* of the strong field. Note that the control device 60 may calculate the d-axis target current Id* of the weak field instead of calculating the d-axis target current Id* of the strong field.

[0092] FIG. 18 shows a block diagram of the temperature increase control executed by the control device 60.

[0093] The three-phase target amplitude calculation unit 161, similar to the three-phase target amplitude calculation unit 61 in Figure 9, acquires the target heat quantity Q* from the higher-level control device 80 for each control period, and calculates the amplitude Iuamp* of the U-phase target current, the amplitude Ivamp* of the V-phase target current, and the amplitude Iwamp* of the W-phase target current based on the acquired target heat quantity Q*.

[0094] Similar to the two-phase target amplitude calculation unit 62 of FIG. 9 , the two-phase target amplitude calculation unit 162 converts the amplitudes Iuamp*, Ivamp*, Iwamp* of the respective phase currents into the amplitude Idamp* of the d-axis target current Id* for each control period based on the amplitudes Iuamp*, Ivamp*, Iwamp* of the respective phase currents and the detected electrical angle θe.

[0095] The target current calculation unit 163 calculates the d-axis target current Id* based on the amplitude Idamp* of the d-axis target current Id* calculated by the two-phase target amplitude calculation unit 162. For example, the target current calculation unit 163 may calculate the amplitude Idamp* of the d-axis target current Id* as the d-axis target current Id* (=Idamp*).

[0096] The two-phase conversion unit 164 converts the U, V, and W phase currents in the three-phase fixed coordinate system into a d-axis current Idr and a q-axis current Iqr in the dq coordinate system based on the detection value of the phase current sensor 51 and the detected electrical angle θe for each control period.

[0097] The target current calculation unit 163 calculates the q-axis target current Iq* for each control period based on the calculated d-axis target current Id* and the above equation (eq8). In this embodiment, the target current calculation unit 163 corresponds to the "target value calculation unit."

[0098] The three-phase control unit 165 functions as an "armature control unit" that generates gate drive signals for the switches SUH, SUL, SVH, SVL, SWH, and SWL of the inverter 20 to feedback-control the calculated d-axis target current Id* with the d-axis current Idr calculated by the two-phase conversion unit 164, and to feedback-control the calculated q-axis target current Iq* with the q-axis current Iqr calculated by the two-phase conversion unit 164. In this generation process, the electrical angle θe and the power supply Vdc detected by the voltage sensor 50 are used. The three-phase control unit 165 outputs the generated gate drive signals to drive circuits that drive the switches SUH, SUL, SVH, SVL, SWH, and SWL. As a result, the d-axis current Idr is controlled to the DC d-axis target current Id*, and the q-axis current Iqr is controlled to the DC q-axis target current Iq*.

[0099] FIG. 19 is a flowchart showing the procedure for temperature increase control according to this embodiment, and corresponds to the process shown in step S11 in FIG.

[0100] In step S30, the target heat quantity Q* is obtained from the upper control device 80, similar to step S20.

[0101] In step S31, the three-phase target amplitude calculation unit 161 calculates the amplitude Iuamp* of the U-phase target current, the amplitude Ivamp* of the V-phase target current, and the amplitude Iwamp* of the W-phase target current based on the target heat quantity Q* obtained in step S30.

[0102] In step S32, the two-phase target amplitude calculation unit 162 calculates the amplitude Idamp* of the d-axis target current Id* based on the amplitudes Iuamp*, Ivamp*, Iwamp* of the phase currents calculated in step S31 and the electrical angle θe.

[0103] In step S33, the target current calculation unit 163 calculates the DC d-axis target current Id* based on the amplitude Idamp* of the d-axis target current Id* calculated in step S33.

[0104] In step S34, the target current calculation unit 163 calculates the DC q-axis target current Iq* based on the calculated d-axis target current Id*.

[0105] In step S35, the two-phase conversion unit 164 calculates the d-axis current Idr and the q-axis current Iqr based on the detection value of the phase current sensor 51 and the electrical angle θe.

[0106] In step S36, the three-phase control unit 165 performs feedback control of the d-axis current Idr calculated in step S36 to the d-axis target current Id* calculated in step S33, and also performs switching control of each switch SUH, SUL, SVH, SVL, SWH, and SWL of the inverter 20 to feedback control the q-axis current Iqr calculated in step S36 to the q-axis target current Iq* calculated in step S34.

[0107] According to the present embodiment described above, similarly to the first embodiment, the teeth 13a, 14a of the pair of gears 13, 14 can be kept pressed against each other to suppress the occurrence of gear rattle noise.

[0108] Fourth Embodiment The fourth embodiment will be described below with reference to the drawings, focusing on differences from the third embodiment. The target current calculation unit 163 of the control device 60 of this embodiment calculates a sinusoidal AC d-axis target current Id* instead of a DC current. More specifically, the target current calculation unit 163 calculates a sinusoidal d-axis target current Id* having an amplitude Idamp* equal to the amplitude Idamp* of the d-axis target current Id* calculated by the two-phase target amplitude calculation unit 162. The target current calculation unit 163 calculates the d-axis target current Id* using, for example, the following equation (eq9):

[0109] Id*=Idamp*×sin(ω×t) (eq9) The target current calculation unit 163 calculates the q-axis target current Iq* based on the calculated d-axis target current Id* and the above equation (eq8). Here, since some rotating electric machines 30 have the following characteristics (C) to (E), the target current calculation unit 163 calculates the d-axis and q-axis target currents Id* and Iq* according to each characteristic.

[0110] (C) Characteristics where Lq>Ld In this case, the target current calculation unit 163 calculates a sinusoidal q-axis target current Iq* that is 180 degrees out of phase with the d-axis target current Id*, as shown in the upper part of Figure 20.

[0111] (D) Characteristics where Lq<Ld In this case, the target current calculation unit 163 calculates a sine wave q-axis target current Iq* in phase with the d-axis target current Id*, as shown in the middle part of FIG.

[0112] (E) Characteristics where Lq = Ld In this case, the target current calculation unit 163 calculates the DC q-axis target current Iq* as shown in the lower part of Fig. 20. In this case, the q-axis target current Iq* is expressed by the following equation (eq10).

[0113] The temperature increase control in this embodiment is the same as the process shown in FIG.

[0114] Other Embodiments The above-described embodiments may be modified as follows.

[0115] When the above equation (eq7) is solved for the d-axis current Id, the following equation (eq11) is derived.

[0116] In this case, the control device 60 of the fourth embodiment may calculate the sinusoidal d-axis target current Id* based on the sinusoidal q-axis target current Iq* and the above equation (eq11).

[0117] In the third and fourth embodiments, the gradual change processing shown in FIGS. 12 to 14 may be executed.

[0118] The temperature rise control of the third and fourth embodiments may be applied to a system including a wound field type rotating electric machine in which the field current Ifr is a constant value.

[0119] The d- and q-axis target currents Id* and Iq* and the field target current If* in the first and second embodiments, or the d- and q-axis target currents Id* and Iq* in the third and fourth embodiments may be calculated so as to satisfy the condition that the time average value of the generated torque over multiple periods of the AC current flowing through the armature winding is offset from 0 by the offset value Toffset.

[0120] Even when the polarity of the generated torque is negative in a portion of one cycle of the generated torque as shown in Fig. 21, or when the polarity of the generated torque is negative in a portion of some of the cycles as shown in Fig. 22, the condition that the time average value of the generated torque over multiple cycles of the AC current flowing through the armature winding is offset from 0 by the offset value Toffset can be satisfied. In this case, even if gear rattle occurs, it is possible to reduce gear rattle noise and the frequency of gear rattle.

[0121] The rotating electric machine is not limited to a synchronous machine, and may be an asynchronous machine such as an induction machine.

[0122] 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.

[0123] 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.

[0124] The target to be heated by the temperature rise control may be, for example, the coolant in the circulation path 400. 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 increased by the temperature rise control.

[0125] 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.

[0126] The switches of the power converter 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.

[0127] 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 may be a unit including both a storage battery and an electric double layer capacitor.

[0128] The mobile body on which the control device is mounted is not limited to a vehicle, but may be, for example, an airplane or a ship. In the case of an airplane, the rotationally driven object is, for example, a propeller, and in the case of a ship, n is, for example, a screw. Furthermore, the device on which the control device is mounted is not limited to a mobile body, but may also be a stationary device.

[0129] The control device and method described herein may be implemented by a special-purpose computer configured with a processor and memory programmed to execute one or more functions embodied in a computer program. Alternatively, the control device and method described herein may be implemented by a special-purpose computer configured with a processor comprising one or more dedicated hardware logic circuits. Alternatively, the control device and method described herein may be implemented by one or more special-purpose computers configured with a combination of a processor and memory programmed to execute one or more functions and a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions to be executed by a computer.

[0130] 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 (30) having a rotor (31) and armature windings (34U to 34W), a power converter (20) electrically connecting the power storage unit and the armature windings and having upper and lower arm switches (SUH to SWL), and at least one pair of gears (13, 14) forming a power transmission mechanism (11) from the rotor to a rotationally driven object (12), rotating by rotational power from the rotor and meshing with each other, the control device (60) for a power converter applied to a system including: a target value calculation unit (63, 67, 163) for calculating d-axis and q-axis target currents (Id*, Iq*) to be passed through the armature winding; an armature control unit (68) that controls the switching of the upper and lower arm switches to control a d-axis current (Idr) flowing through the armature winding to the calculated d-axis target current, and to control a q-axis current (Iqr) flowing through the armature winding to the calculated q-axis target current, wherein the target value calculation unit calculates the d- and q-axis target currents so as to satisfy a first condition that the torque generated by the rotor is set to a torque that can maintain the rotor in a stopped state, and a second condition that the time average value of the generated torque in one cycle or multiple cycles of the AC current flowing through the armature winding is offset from zero. [Configuration 2] The control device for a power converter according to Configuration 1, wherein the rotating electric machine is a permanent magnet field type rotating electric machine including the rotor having a permanent magnet (35), or a wound field type rotating electric machine including the rotor having a field winding (32) through which a constant current flows, and the second condition is a condition that the generated torque is offset in one of positive and negative directions during execution of the switching control by the armature control unit. [Configuration 3] The control device for a power converter according to Configuration 2, wherein the target value calculation unit (163) calculates the DC d- and q-axis target currents so as to satisfy the first and second conditions. [Configuration 4] The control device for a power converter according to Configuration 2, wherein the target value calculation unit (163) calculates the sinusoidal d-axis target current and calculates the sinusoidal q-axis target current having a phase difference of 0 degrees or 180 degrees with respect to the d-axis target current so as to satisfy the first and second conditions.[Configuration 5] The control device for a power converter according to any one of Configurations 2 to 4, further comprising an initial target value calculation unit (69A) that calculates initial d- and q-axis target currents (Kt×Id*, Kt×Iq*) that are the d- and q-axis target currents used during a predetermined period from a start timing of the switching control by the armature control unit, wherein the initial target value calculation unit gradually increases the initial d- and q-axis target currents from 0 toward the d- and q-axis target currents calculated by the target value calculation unit during the predetermined period. [Configuration 6] The control device for a power converter according to any one of Configurations 2 to 5, further comprising an end target value calculation unit (69B) that calculates end d- and q-axis target currents (Kt×Id*, Kt×Iq*) that are the d- and q-axis target currents used during a predetermined period before a termination timing of the switching control by the armature control unit, wherein the end target value calculation unit gradually decreases the end d- and q-axis target currents from the d- and q-axis target currents calculated by the target value calculation unit toward 0 during the predetermined period. [Configuration 7] The control device for a power converter according to Configuration 1, wherein the rotating electric machine is a wound-field type rotating electric machine including the rotor having a field winding (32), the power converter is a first power converter, the system is provided with a second power converter (40) that electrically connects the power storage unit and the field winding, a target field calculation unit (65) that calculates a sinusoidal field target current (If*), and a field control unit (66) that performs switching control of the second power converter to control a field current (Ifr) flowing through the field winding to the calculated field target current, and the second condition is a condition that the generated torque is offset in one of positive and negative directions during execution of the switching control by the armature control unit and the field control unit. [Configuration 8] The control device for a power converter according to Configuration 7, wherein the target value calculation unit (63, 67) calculates the d-axis target current in a sinusoidal waveform having a phase difference of 180 degrees or 0 degrees with respect to the field target current so as to satisfy the first condition and the second condition.[Configuration 9] The control device for a power converter according to Configuration 8, wherein the target value calculation unit calculates the q-axis target current having a sinusoidal waveform, and calculates the d-axis target current such that the magnitude of the d-axis current is offset in an increasing direction when the polarity of the q-axis target current is switched. [Configuration 10] The control device for a power converter according to any one of Configurations 7 to 9, further comprising an initial target value calculation unit (69A) that calculates initial d- and q-axis target currents (Kt×Id*, Kt×Iq*) that are the d- and q-axis target currents used during a predetermined period from a start timing of the switching control by the armature control unit, and an initial field target current (Kt×If*) that is the field target current used during the predetermined period, and wherein the initial target value calculation unit gradually increases the initial d- and q-axis target currents from 0 toward the d- and q-axis target currents calculated by the target value calculation unit, and gradually increases the initial field target current from 0 toward the field target current calculated by the target field calculation unit during the predetermined period. [Configuration 11] The control device for a power converter according to any one of Configurations 7 to 10, further comprising an end target value calculation unit (69B) that calculates end d, q-axis target currents (Kt×Id*, Kt×Iq*) that are the d, q-axis target currents used in a predetermined period before a termination timing of the switching control by the armature control unit, and an end field target current (Kt×If*) that is the field target current used in the predetermined period, wherein the end target value calculation unit gradually decreases the end d, q-axis target currents from the d, q-axis target currents calculated by the target value calculation unit toward zero, and gradually decreases the end field target current from the field target current calculated by the target field calculation unit toward zero, during the predetermined period. [Configuration 12] The control device for a power converter according to any one of Configurations 1 to 11, wherein the system is a system mounted on a vehicle, and the armature control unit performs the switching control while the vehicle is stopped.[Configuration 13] The control device for a power converter according to any one of configurations 1 to 12, wherein the system includes a heat transfer unit (400, 401) that transfers heat generated in the power converter to a temperature-raising target (10), and a determination unit that determines whether or not there is a temperature-raising request for the temperature-raising target, and the armature control unit performs the switching control when it is determined that there is the temperature-raising request.

[0131] 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 (30) having a rotor (31) and armature windings (34U to 34W); a power converter (20) electrically connecting the power storage unit and the armature windings and having upper and lower arm switches (SUH to SWL); and at least a pair of gears (13, 14) constituting a power transmission mechanism (11) from the rotor to a rotationally driven object (12), rotating by the rotational power from the rotor and meshing with each other, the control device (60) for a power converter applied to a system including: a target value calculation unit (63, 67, 163) that calculates d-axis and q-axis target currents (Id*, Iq*) to be passed through the armature winding; an armature control unit (68) that performs switching control of the upper and lower arm switches to control a d-axis current (Idr) flowing through the armature winding to the calculated d-axis target current, and to control a q-axis current (Iqr) flowing through the armature winding to the calculated q-axis target current, wherein the target value calculation unit calculates the d- and q-axis target currents so as to satisfy a first condition that the torque generated by the rotor is set to a torque that can maintain a stopped state of the rotor, and a second condition that a time average value of the generated torque in one cycle or multiple cycles of the AC current passed through the armature winding is offset from 0.

2. The control device for a power converter as described in claim 1, wherein the rotating electric machine is a permanent magnet field type rotating electric machine having a rotor with a permanent magnet (35), or a wound field type rotating electric machine having a rotor with a field winding (32) through which a constant current flows, and the second condition is a condition that the generated torque is offset in one of the positive and negative directions during the execution of the switching control by the armature control unit.

3. The control device for a power converter according to claim 2, wherein the target value calculation unit (163) calculates the d- and q-axis target DC currents so as to satisfy the first condition and the second condition.

4. The control device for a power converter as described in claim 2, wherein the target value calculation unit (163) calculates the d-axis target current having a sinusoidal shape so as to satisfy the first condition and the second condition, and calculates the q-axis target current having a sinusoidal shape with a phase difference of 0 degrees or 180 degrees with respect to the d-axis target current.

5. A control device for a power converter as described in any one of claims 2 to 4, further comprising an initial target value calculation unit (69A) that calculates initial d- and q-axis target currents (Kt×Id*, Kt×Iq*) which are the d- and q-axis target currents used during a predetermined period from the start timing of the switching control by the armature control unit, wherein the initial target value calculation unit gradually increases the initial d- and q-axis target currents from 0 toward the d- and q-axis target currents calculated by the target value calculation unit during the predetermined period.

6. A control device for a power converter as described in any one of claims 2 to 4, further comprising an end target value calculation unit (69B) that calculates end d, q axis target currents (Kt x Id*, Kt x Iq*) which are the d, q axis target currents used during a predetermined period before the end timing of the switching control by the armature control unit, and the end target value calculation unit gradually reduces the end d, q axis target currents from the d, q axis target currents calculated by the target value calculation unit toward zero during the predetermined period.

7. The control device for a power converter according to claim 1, wherein the rotating electric machine is a wound field type rotating electric machine including a rotor having a field winding (32), the power converter is a first power converter, the system is provided with a second power converter (40) that electrically connects the storage unit and the field winding, and is provided with: a target field calculation unit (65) that calculates a sinusoidal field target current (If*), and a field control unit (66) that performs switching control of the second power converter to control a field current (Ifr) flowing through the field winding to the calculated field target current, and the second condition is a condition that the generated torque is offset in one of the positive and negative directions during the execution of the switching control by the armature control unit and the field control unit.

8. A control device for a power converter as described in claim 7, wherein the target value calculation unit (63, 67) calculates the d-axis target current having a sinusoidal shape with a phase difference of 180 degrees or 0 degrees from the field target current so as to satisfy the first condition and the second condition.

9. A control device for a power converter as described in claim 8, wherein the target value calculation unit calculates the q-axis target current having a sinusoidal waveform, and calculates the d-axis target current such that the magnitude of the d-axis current is offset in the increasing direction when the polarity of the q-axis target current is switched.

10. A control device for a power converter as claimed in any one of claims 7 to 9, further comprising an initial target value calculation unit (69A) that calculates initial d, q axis target currents (Kt x Id*, Kt x Iq*) which are the d, q axis target currents used during a predetermined period from the start timing of the switching control by the armature control unit, and an initial field target current (Kt x If*) which is the field target current used during the predetermined period, wherein the initial target value calculation unit gradually increases the initial d, q axis target currents from 0 towards the d, q axis target currents calculated by the target value calculation unit, and gradually increases the initial field target current from 0 towards the field target current calculated by the target field calculation unit, during the predetermined period.

11. A control device for a power converter as claimed in any one of claims 7 to 9, further comprising an end target value calculation unit (69B) that calculates end d, q axis target currents (Kt x Id*, Kt x Iq*) which are the d, q axis target currents used in a predetermined period before the end timing of the switching control by the armature control unit, and an end field target current (Kt x If*) which is the field target current used in the predetermined period, wherein the end target value calculation unit gradually decreases the end d, q axis target currents from the d, q axis target currents calculated by the target value calculation unit toward 0, and gradually decreases the end field target current from the field target current calculated by the target field calculation unit toward 0, during the predetermined period.

12. A power converter control device according to any one of claims 1 to 4 and 7 to 9, wherein the system is a system mounted on a vehicle, and the armature control unit performs the switching control while the vehicle is stopped.

13. A control device for a power converter as described in any one of claims 1 to 4 and 7 to 9, wherein the system is provided with a heat transfer unit (400, 401) that transfers heat generated in the power converter to a target (10) to be heated, and a determination unit that determines whether or not there is a request to heat the target, and the armature control unit performs the switching control when it is determined that there is a request to heat the target.

14. A program applied to a system including: an electric storage unit (10); a rotating electric machine (30) having a rotor (31) and armature windings (34U-34W); a power converter (20) electrically connecting the electric storage unit and the armature windings and having upper and lower arm switches (SUH-SWL); at least one pair of gears (13, 14) constituting a power transmission mechanism (11) from the rotor to a rotationally driven object (12), which rotate by the rotational power from the rotor and mesh with each other; and a computer (60a), the program comprising: a target value calculation process for calculating d-axis and q-axis target currents (Id*, Iq*) to be passed through the armature windings, a process of controlling switching of the upper and lower arm switches so as to control a d-axis current (Idr) flowing through the armature winding to the calculated d-axis target current, and a process of controlling a q-axis current (Iqr) flowing through the armature winding to the calculated q-axis target current, wherein the target value calculation process is a process of calculating the d- and q-axis target currents so as to satisfy a first condition that the torque generated by the rotor is set to a torque that can maintain a stopped state of the rotor, and a second condition that a time average value of the generated torque in one cycle or multiple cycles of an AC current passed through the armature winding is offset from 0.

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