Inverter control device, program, and inverter control method

Abstract

An inverter control device (50) comprises: a determination unit (67) that determines whether or not there is a temperature increase request for a temperature increase target (10); and a setting unit (65) that sets a switching mode of an inverter (30). When it is determined that there is the temperature increase request, the setting unit performs change processing for changing the switching mode so as to increase, as compared to a case where it is determined that there is no temperature increase request, a component that is a voltage component included in the inter-line voltage of armature windings (23U to 23W) of a rotating electrical machine (20) and fluctuates at the switching frequency of the inverter.

Description

Inverter control device, program, and inverter control method CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2024-022743 filed on February 19, 2024, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to an inverter control device, a program, and an inverter control method.

[0003] As described in Patent Document 1, a control device is known that is applied to a system including a rotating electric machine having an armature winding and an inverter electrically connecting the armature winding and a power storage unit. When the control device determines that there is a temperature increase request for a temperature increase target, the control device increases a field weakening current while maintaining the magnitude of the current vector flowing through the armature winding. This increases copper loss generated in the rotating electric machine and increases the amount of heat generated by the rotating electric machine.

[0004] Japanese Patent Application Laid-Open No. 2023-16559

[0005] A new technique is desired that can increase the heat generation amount of a rotating electrical machine when there is a demand for increasing the temperature of a target for temperature increase.

[0006] A primary object of the present disclosure is to provide an inverter control device, a program, and an inverter control method that can increase the heat generation amount of a rotating electrical machine when there is a temperature increase request for a temperature increase target.

[0007] The present disclosure relates to an inverter control device that is applied to a system including a rotating electric machine having an armature winding wound around an armature core, and an inverter that electrically connects the armature winding and a power storage unit, the inverter control device comprising: a determination unit that determines whether or not there is a temperature increase request for a temperature increase target; and a setting unit that sets a switching mode of the inverter, wherein when it is determined that there is a temperature increase request, the setting unit performs a change process that changes the switching mode so as to increase the voltage component contained in the line voltage of the armature winding, which component fluctuates at the switching frequency of the inverter, compared to when it is determined that there is no temperature increase request.

[0008] This increases the high-frequency components of the magnetic flux that are generated when current is applied to the armature winding and that fluctuate at the switching frequency, thereby increasing the iron loss generated in the rotating electric machine and increasing the amount of heat generated by the rotating electric machine.

[0009] 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. 10 is a flowchart of processing executed by a control device according to a third embodiment; FIG. 11 is a time chart showing an example of switching between heat generation mode and normal mode; FIG. 12 is an overall configuration diagram of a system according to a fourth embodiment; FIG. 13 is a flowchart of processing executed by a control device; FIG. 14 is a diagram showing the relationship between high-frequency components included in line voltage and phase difference; and FIG. 15 is a time chart showing the transition of a carrier signal used in heat generation mode.

[0010] Several embodiments will be described with reference to the drawings. In several embodiments, functionally and / or structurally corresponding and / or associated parts may be designated by the same reference numerals or reference numerals that differ in the hundredth or more digit. For corresponding and / or associated parts, reference may be made to the descriptions of other embodiments.

[0011] A first embodiment of a control device according to the present disclosure will be described below with reference to the drawings. The control device of the present embodiment is applied to a system mounted on an electrically powered vehicle such as an electric vehicle or a hybrid vehicle.

[0012] As shown in FIG. 1 , the system 200 includes a battery 10 (corresponding to a "power storage unit"), which is a DC power source, a rotating electrical machine 20, and an inverter 30. The battery 10 is, for example, a battery pack including a series connection of unit cells. The unit cell is a single battery cell or a series connection of multiple battery cells. The battery cell is, for example, a secondary battery such as a lithium-ion battery.

[0013] The rotating electric machine 20 is an on-board main engine that serves as a power source for running the vehicle. The rotating electric machine 20 includes a stator 21 as an armature and a rotor 24. The rotor 24 is capable of transmitting power to the drive wheels of the vehicle. In this embodiment, the rotating electric machine 20 is a permanent magnet field type synchronous machine. The rotor 24 includes a rotor core 25 and permanent magnets 26 (e.g., neodymium magnets) that serve as field poles provided on the rotor core 25.

[0014] The stator 21 includes an armature core 22 and an armature winding wound around the armature core 22. The armature winding includes a U-phase winding 23U, a V-phase winding 23V, and a W-phase winding 23W, and is a star-connected winding. The phase windings 23U, 23V, and 23W are arranged on the armature core 22 with a 120-degree electrical angle offset.

[0015] The inverter 30 is a power conversion circuit that converts DC power supplied from the battery 10 into three-phase AC power and supplies it to the armature windings. The inverter 30 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, each of the switches SUH to SWL is a voltage-controlled semiconductor switching element, more specifically, an N-channel MOSFET. The high-potential terminal of each of the switches SUH to SWL is the drain, and the low-potential terminal is the source. Each of the switches SUH to SWL has a body diode. Specifically, the U-, V-, and W-phase upper-arm switches SUH, SVH, and SWH have U-, V-, and W-phase upper-arm diodes DUH, DVH, and DWH, respectively, and the U-, V-, and W-phase lower-arm switches SUL, SVL, and SWL have U-, V-, and W-phase lower-arm diodes DUL, DVL, and DWL, respectively.

[0016] In each phase, first ends of the windings 23U, 23V, 23W are connected to the sources of the upper switches SUH, SVH, SWH and the drains of the lower switches SUL, SVL, SWL, etc. In each phase, second ends of the windings 23U, 23V, 23W are connected to the neutral point.

[0017] In each phase, the drains of the upper arm switches SUH, SVH, and SWH are connected to the positive terminal of the battery 10. In each phase, the sources of the lower arm switches SUL, SVL, and SWL are connected to the negative terminal of the battery 10.

[0018] The system 200 includes a capacitor 31. The capacitor 31 functions as a smoothing capacitor. The capacitor 31 is connected in parallel to a series connection of the upper arm switches SUH to SWH and the lower arm switches SUL to SWL of each phase. The capacitor 31 may be built into the inverter 30 or may be provided externally to the inverter 30.

[0019] As shown in FIG. 2 , the system 200 includes a cooling device 210 that cools the inverter 30, the rotating electric machine 20, and the battery 10 when switching control of the inverter 30 is performed to run the vehicle. Specifically, the cooling device 210 includes a circulation path 100 through which coolant circulates, an electric water pump 101, a radiator 102, and an electric fan 103. The water pump 101 circulates the coolant by being driven by power supply. In the example shown in FIG. 2 , the inverter 30, the rotating electric machine 20, and the battery 10 are arranged in this order downstream of the water pump 101 in the circulation path 100. Note that the arrangement order of the devices in the circulation path 100 is not limited to the order shown in FIG. 2 .

[0020] A radiator 102 is provided in the circulation path 100 between the water pump 101 and the battery 10. The radiator 102 cools the coolant that flows in through the circulation path 100 and supplies it to the water pump 101. The coolant that flows into the radiator 102 is cooled by wind blown onto the radiator 102 as the vehicle moves and wind blown onto the radiator 102 by rotating and driving a fan 103. In this embodiment, the circulation path 100, the coolant circulating through the circulation path 100, and the water pump 101 correspond to a "heat transfer unit."

[0021] Returning to the explanation of FIG. 1, the system includes a current sensor 40 , a rotation angle sensor 41 , a voltage sensor 42 , a battery temperature sensor 43 , a motor temperature sensor 44 and an inverter temperature sensor 45 .

[0022] The current sensor 40 detects the phase currents flowing through the phase windings 23U, 23V, and 23W. The rotation angle sensor 41 is, for example, a resolver, and detects the electrical angle of the rotor 24. The voltage sensor 42 detects the voltage across the capacitor 31. The battery temperature sensor 43 detects the temperature of the battery 10.

[0023] The motor temperature sensor 44 detects the temperature of the rotating electric machine 20. The motor temperature sensor 44 detects, for example, the temperatures of the armature windings 23U to 23W and the rotor 24. The inverter temperature sensor 45 detects the temperature of the inverter 30. The inverter temperature sensor 45 detects, for example, the temperatures of the switches SUH to SWL that configure the inverter 30.

[0024] The detection values ​​of the sensors 40 to 45 are input to a control device 50 included in the system 200. The control device 50 is an electronic control unit (ECU) that performs various controls of the system 200, and includes a processor 51 and a storage unit 52 as hardware. In the control device 50, the processor 51 and the storage unit 52 are connected to each other via a communication bus 53. In the system 200, each on-board device can be controlled by an ECU corresponding to that device. However, for convenience, multiple ECUs are shown as a single control device 50 in FIG. 1.

[0025] The memory unit 52 includes a memory and a storage as hardware. The memory is a storage device for storing data used in the processing of the control device 50. The memory provides the processor 51 with a working area for temporary use when the processor 51 performs processing, for example. The memory includes, for example, a ROM or a RAM. The storage is a storage device for storing various programs and data to be read and executed by the processor 51, and is a non-transitory tangible storage medium. The storage includes, for example, an HDD or a flash memory. The storage stores program information and the like for the processing shown in FIGS. 3 and 6, which will be described later.

[0026] For example, program information stored on a non-transient physical recording medium is installed in the storage unit 52. The recording medium is, for example, a USB memory, a CD-ROM, or a DVD. Also, for example, program information transmitted via a communication network, such as over the air (OTA), is installed in the storage unit 52.

[0027] The water pump 101 and the fan 103 may be driven by a control device separate from the control device 50. However, in this embodiment, for convenience, it is assumed that the water pump 101 and the fan 103 are driven by the control device 50.

[0028] The control device 50 controls the on / off of each of the switches SUH to SWL of the inverter 30 in order to control the control amount of the rotary electric machine 20 to a command value. In this embodiment, the control amount is torque.

[0029] FIG. 3 is a block diagram showing the control process of the rotating electrical machine 20 executed by the control device 50. As shown in FIG.

[0030] The command value calculation unit 60 calculates a d-axis current command value Id* and a q-axis current command value Iq* in the dq coordinate system based on the command torque Trq* received from a higher-level control device than the control device 50 .

[0031] The two-phase conversion unit 61 calculates the d-axis current value Idr and the q-axis current value Iqr based on the phase currents Iur, Ivr, and Iwr detected by the current sensor 40 and the electrical angle θr detected by the rotation angle sensor 41.

[0032] The current feedback unit 62 calculates a d-axis voltage command value Vd* and a q-axis voltage command value Vq* based on the d- and q-axis current command values ​​Id* and Iq* and the d- and q-axis current values ​​Idr and Iqr. Specifically, the current feedback unit 62 calculates a d-axis current deviation, which is the difference between the d-axis current command value Id* and the d-axis current value Idr, and calculates a d-axis voltage command value Vd* as a manipulated variable for feedback-controlling the calculated d-axis current deviation to zero. The current feedback unit 62 calculates a q-axis current deviation, which is the difference between the q-axis current command value Iq* and the q-axis current value Iqr, and calculates a q-axis voltage command value Vq* as a manipulated variable for feedback-controlling the calculated q-axis current deviation to zero. The feedback control is, for example, proportional-plus-integral control.

[0033] The three-phase converter 63 calculates U-, V-, and W-phase voltage command values ​​Vu*, Vv*, and Vw* based on the d- and q-axis voltage command values ​​Vd*, Vq* and the electrical angle θr. The U-, V-, and W-phase voltage command values ​​Vu*, Vv*, and Vw* are command values ​​for the voltages applied to the U-, V-, and W-phase windings 23U, 23V, and 23W.

[0034] The setting unit 64 generates drive signals for the switches SUH to SWL of the inverter 30. The drive signals include an ON command and an OFF command for the switches.

[0035] Based on the generated drive signal, the switch control unit 65 controls the charge / discharge current of the gates of the switches SUH to SWL of the inverter 30. This causes the switching of the switches SUH to SWL of the inverter 30 to be controlled in accordance with the drive signal. The switching patterns of the switches of the inverter 30, which are switched in accordance with the drive signal, are shifted in phase by 120 electrical degrees for each phase.

[0036] The carrier generating unit 66 generates a carrier signal for generating drive signals for the switches SUH to SWL of the inverter 30. In this embodiment, the carrier signal is a triangular wave signal with equal increasing and decreasing speeds. In this embodiment, the maximum value of the carrier signal is 1, the minimum value of the carrier signal is −1, and the median value of the carrier signal is 0.

[0037] The setting unit 64 calculates U-, V-, and W-phase normalized command values ​​Dutyu, Dutyv, and Dutyw by normalizing the U-, V-, and W-phase voltage command values ​​Vu*, Vv*, and Vw* by the detection value of the voltage sensor 42 (hereinafter referred to as the power supply voltage Vsr). Specifically, the U-, V-, and W-phase normalized command values ​​Dutyu, Dutyv, and Dutyw are values ​​obtained by dividing the U-, V-, and W-phase voltage command values ​​Vu*, Vv*, and Vw* by half the power supply voltage Vsr. In this embodiment, the U-, V-, and W-phase normalized command values ​​Dutyu, Dutyv, and Dutyw correspond to "modulation waves."

[0038] The setting unit 64 generates drive signals for each switch SUH to SWL of the inverter 30 by PWM processing based on a magnitude comparison between the U-, V-, and W-phase normalized command values ​​Dutyu, Dutyv, and Dutyw and a common carrier signal SgC shown in FIG. 4. In FIG. 4, Tc represents one period of the carrier signal SgC. One period Tc of the carrier signal SgC corresponds to one switching period Tsw of each switch SUH to SWL of the inverter 30. The frequency fc (=1 / Tc) of the carrier signal SgC corresponds to the switching frequency fsw (=1 / Tsw) of each switch SUH to SWL of the inverter 30.

[0039] The determination unit 67 determines whether or not there is a temperature increase request for a temperature increase target constituting the system 200. In this embodiment, the temperature increase target is the battery 10. If the determination unit 67 determines that the detected value of the battery temperature sensor (hereinafter referred to as battery temperature Tbat) is equal to or higher than the target temperature Ttgt, it determines that there is no temperature increase request. On the other hand, if the determination unit 67 determines that the battery temperature Tbat is lower than the target temperature Ttgt, it determines that there is a temperature increase request.

[0040] When it is determined that there is no temperature increase request, the control device 50 performs the normal mode in which drive signals for the switches SUH to SWL of the inverter 30 are generated by the method using the carrier signal SgC described above.

[0041] On the other hand, when the control device 50 determines that there is a temperature increase request, it changes the control mode from the normal mode to a heat generation mode that increases the heat generated by the rotating electric machine 20. The control device 50 drives the water pump 101 so that the heat generated in the heat generation mode is transferred to the battery 10, which is the target for temperature increase, via the coolant in the circulation path 100. The control device 50 continues the heat generation mode, for example, until the battery temperature Tbat reaches the target temperature Ttgt. The heat generation mode quickly increases the temperature of the battery 10, thereby shortening the charging time of the battery 10 using an external charger, for example. The heat generation mode can be executed while the vehicle is running or stopped.

[0042] The heat generation mode will be described with reference to FIG.

[0043] The setting unit 64 shifts the phases of the carrier signals to be compared with the U-, V-, and W-phase normalized command values ​​Dutyu, Dutyv, and Dutyw by 120 electrical degrees. In FIG. 5 , SgU is a U-phase carrier signal to be compared with the U-phase normalized command value Dutyu, SgV is a V-phase carrier signal to be compared with the V-phase normalized command value Dutyv, and SgW is a W-phase carrier signal to be compared with the W-phase normalized command value Dutyw. Each of the carrier signals SgU, SgV, and SgW has a maximum value of 1, a minimum value of −1, and a median value of 0. Furthermore, each of the carrier signals SgU, SgV, and SgW has the same cycle Tc, which is the same as the cycle Tc of the carrier signal SgC in FIG. 4 .

[0044] 5, α is the phase difference between the carrier signals, and the interval between the timings at which the carrier signals SgU, SgV, and SgW reach their maximum values ​​is shown as the phase difference α.

[0045] When the phase difference α in the heat generation mode is 120 degrees, compared to when the phase difference α is 0 in the normal mode, calculations have confirmed an increase in the voltage components contained in the line voltage Vuv between the U- and V-phase windings 23U and 23V, the line voltage Vvw between the V- and W-phase windings 23V and 23W, and the line voltage Vwu between the W- and U-phase windings 23W and 23U, which vary with the carrier signal frequency (=fc=1 / Tc). This increase also increases the high-frequency components of the magnetic flux generated by the current flowing through the phase windings 23U, 23V, and 23W, which vary with the carrier signal frequency. It has also been confirmed by calculations that this increase can increase iron loss generated in the rotating electric machine 20, such as the armature core 22, magnet 26, and rotor core 25, as shown in FIG. 6 . The increase in iron loss can increase the amount of heat generated per unit time by the rotating electric machine 20.

[0046] 7 shows a flowchart of the control process of the rotary electric machine 20 executed by the control device 50. The process shown in FIG. 7 is repeatedly executed by the processor 51 of the control device 50, for example, at a predetermined control cycle.

[0047] In step S10, the three-phase conversion unit 63 calculates U-, V-, and W-phase voltage command values ​​Vu*, Vv*, and Vw*.

[0048] In step S11, the setting unit 64 calculates U-, V-, and W-phase normalized command values ​​Dutyu, Dutyv, and Dutyw based on the calculated U-, V-, and W-phase voltage command values ​​Vu*, Vv*, and Vw*.

[0049] In step S12, it is determined whether or not there is a temperature increase request in the determination unit 67. If it is determined in step S12 that there is no temperature increase request, the process proceeds to step S13, where the normal mode is performed.

[0050] On the other hand, if it is determined in step S12 that there is a temperature increase request, the process proceeds to step S13, where the heat generation mode is performed.

[0051] Incidentally, the control device 50 may execute the heat generation mode on the condition that it determines that the amplitudes of the normalized command values ​​Dutyu, Dutyv, and Dutyw are equal to or less than a predetermined value Ath (< 1). The predetermined value Ath may be set to, for example, "0.2<Ath≦0.7," "0.2<Ath≦0.6," "0.2<Ath≦0.5," "0.3<Ath≦0.7," "0.3<Ath≦0.6," or "0.3<Ath≦0.5."

[0052] According to the heat generation mode of the present embodiment described above in detail, it is possible to increase the iron loss generated in the rotating electrical machine 20, thereby increasing the amount of heat generated by the rotating electrical machine 20. This allows the temperature of the battery 10 to be raised quickly.

[0053] Second Embodiment A second embodiment will now be described with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, the control device 50 changes the heat generation mode depending on the temperature of the rotor 24.

[0054] Fig. 8 shows a flowchart of the control process of the rotary electric machine 20 executed by the control device 50. The process shown in Fig. 8 is repeatedly executed by the processor 51, for example, at a predetermined control period.

[0055] If it is determined in step S12 that there is a temperature increase request, the process proceeds to step S15, where it is determined whether the temperature of the rotor 24 detected by the motor temperature sensor 44 (hereinafter referred to as the rotor temperature Trot) exceeds a temperature threshold value Trth. The temperature threshold value Trth is set to a value that can prevent demagnetization of the magnet 26, for example.

[0056] If it is determined in step S15 that the rotor temperature Trot is equal to or lower than the temperature threshold value Trth, the process proceeds to step S14, where the heat generation mode described in the first embodiment is performed.

[0057] On the other hand, if it is determined in step S15 that the rotor temperature Trot exceeds the temperature threshold value Trth, the process proceeds to step S16, where the setting unit 64 performs a heat generation mode different from the heat generation mode in step S14.

[0058] As shown in Fig. 9 , the setting unit 64 uses, as the carrier signal to be compared with the normalized command value of one of the three phases, a carrier signal whose phase is shifted by 180 electrical degrees from the carrier signals to be compared with the normalized command values ​​of the remaining two phases. Fig. 9 shows an example in which the U- and W-phase carrier signals SgU and SgW have the same phase, and the V-phase carrier signal SgV has a phase shift of 180 degrees from the U- and W-phase carrier signals SgU and SgW. One cycle Tc of each of the carrier signals SgU, SgV, and SgW in Fig. 9 is the same as one cycle Tc of each of the carrier signals SgU, SgV, and SgW in Fig. 5 .

[0059] The amount of heat generated per unit time by the rotating electric machine 20 is greater in the heat generation mode of step S16 than in the normal mode. Furthermore, the proportion of the increase in iron loss in the stator 21 in the heat generation mode of step S16 compared to the normal mode is higher than the proportion of the increase in iron loss in the rotor 24. This is because, for example, high-frequency magnetic flux generated on the stator 21 side is blocked by the magnet 26, which has a high magnetic resistance. This makes it possible to suppress the temperature rise of the rotor 24 while increasing the amount of heat generated.

[0060] Third Embodiment A third embodiment will be described below with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, the content of the heat generation mode is changed.

[0061] 10 is a flowchart showing the control process of the rotary electric machine 20 executed by the control device 50. The process shown in FIG. 10 is repeatedly executed by the processor 51, for example, at a predetermined control cycle.

[0062] If it is determined in step S12 that there is a temperature increase request, the process proceeds to step S17, where the setting unit 64 sets the control ratio Tration. As shown in Fig. 11, the control ratio Tration is the ratio of the execution period TH of the heat generation mode to the specified period TA. During the specified period TA, the normal mode is executed during the period (TA-TH) other than the execution period TH of the heat generation mode.

[0063] In this embodiment, first, the temperature deviation ΔT (=Ttgt−Tbat) is calculated by subtracting the battery temperature Tbat from the target temperature Ttgt. Then, when the calculated temperature deviation ΔT is large, the control ratio T ratio is set higher than when the temperature deviation ΔT is small. Specifically, the control ratio T ratio is set higher continuously or in stages as the temperature deviation ΔT increases. As a result, when the degree of decrease in the temperature of the battery 10 relative to the target temperature Ttgt is large and the required amount of heat generation per unit time is large, the execution period TH of the heat generation mode can be lengthened, and the amount of heat generation can be increased.

[0064] In step S18, based on the control ratio Tratio set in step S17, the heat generation mode (corresponding to the "second switching mode") of step S14 in FIG. 7 and the normal mode (corresponding to the "first switching mode") of step S13 are alternately switched.

[0065] The specified frequency fA, which is the reciprocal of the specified period TA, is set to a value lower than the frequency of each carrier signal SgU, SgV, SgW, and may be set to, for example, "20 Hz≦fA≦100 Hz," "20 Hz≦fA≦80 Hz," "20 Hz≦fA≦60 Hz," "20 Hz≦fA≦40 Hz," "40 Hz≦fA≦100 Hz," "60 Hz≦fA≦100 Hz," "80 Hz≦fA≦100 Hz," "40 Hz≦fA≦80 Hz," or "50 Hz≦fA≦70 Hz."

[0066] According to the present embodiment described above, heat can be generated according to the required heat generation amount per unit time.

[0067] <Modification of the Third Embodiment> In step S16 of FIG. 8, switching based on the control ratio of the third embodiment may be performed.

[0068] Fourth Embodiment A fourth embodiment will be described below with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, the configuration of a system 200 is changed as shown in FIG.

[0069] The system 200 includes a first battery 10A, a second battery 10B, and a connection path 32. The first battery 10A and the second battery 10B are connected in series. The rated voltage of the first battery 10A is the same as the rated voltage of the second battery 10B, for example.

[0070] The neutral points of the phase windings 23U, 23V, and 23W are connected to the negative terminal of the first battery 10A and the positive terminal of the second battery 10B by connection paths 32. This configuration allows a zero-phase current to flow through the phase windings 23U, 23V, and 23W, increasing the degree of freedom in setting the phase difference α of the carrier signals. The zero-phase current is the sum of the three-phase currents.

[0071] 13 is a flowchart showing the control process of the rotary electric machine 20 executed by the control device 50. The process shown in FIG. 13 is repeatedly executed by the processor 51, for example, at a predetermined control cycle.

[0072] If it is determined in step S12 that a temperature increase request exists, the process proceeds to step S19, where the setting unit 64 calculates the temperature deviation ΔT described in the third embodiment. The larger the calculated temperature deviation ΔT, the greater the phase difference α (0<α≦120) between the carrier signals SgU, SgV, and SgW, either continuously or stepwise. It has been confirmed by calculation that the greater the phase difference α, the greater the component of the voltage components contained in the line voltages Vuv, Vvw, and Vwu that vary with the frequency of the carrier signal, as shown in FIG. 14 . It has also been confirmed by calculation that the greater the component that varies with the frequency of the carrier signal, the greater the iron loss generated in the rotating electric machine 20. The increased iron loss increases the amount of heat generated per unit time by the rotating electric machine 20. FIG. 15 shows an example in which the phase difference α is set to 60 degrees. When the phase difference α is 120 degrees, the amount of heat generated per unit time is maximized. It should be noted that the smaller the phase difference α, the higher the proportion of the heat generated by the stator 21 in the heat generated by the rotary electric machine 20 per unit time.

[0073] According to the present embodiment described above, heat can be generated according to the required heat generation amount per unit time.

[0074] Other Embodiments The above-described embodiments may be modified as follows.

[0075] The target to be heated in the heat generation mode may be, for example, the coolant in the circulation path 100. If the vehicle is equipped with an air conditioning system that uses the coolant as a heat source for heating the passenger compartment, the heat generation mode can quickly raise the temperature of the heating heat source. In this case, the control device 50 may determine that a temperature increase request exists when, for example, it determines that the value detected by a water temperature sensor that detects the coolant temperature is lower than the target temperature.

[0076] The heat transfer unit is not limited to a unit that uses cooling water as a cooling fluid, and may be, for example, an air-cooled unit that uses gas (air) as a cooling fluid, or may be a metal heat sink. When a heat sink is used as the heat transfer unit, for example, the inverter 30 and the battery 10 may be provided on the heat sink.

[0077] The carrier signal is not limited to a triangular wave signal, but may be, for example, a sawtooth wave signal.

[0078] In each of the above embodiments, the control device 50 may generate the drive signal by PWM processing based on space vector modulation, instead of PWM processing based on a magnitude comparison between the command value and the carrier signal. Furthermore, the control device 50 may generate the drive signal based on a pulse pattern that is information that associates switch ON and OFF commands with electrical angles, without using a carrier signal.

[0079] The DC power source is not limited to a battery, and may be, for example, a fuel cell.

[0080] The rotating electric machine is not limited to a permanent magnet field type synchronous machine, but may be, for example, a wound field type synchronous machine having a field winding on the rotor.Furthermore, the rotating electric machine is not limited to a synchronous machine, but may be, for example, an induction machine.

[0081] The semiconductor switches that make up the inverter are not limited to N-channel MOSFETs, but may also be IGBTs, for example. In this case, the high-potential terminal of the switch is the collector, and the low-potential terminal is the emitter. Also, a freewheeling diode is connected in reverse parallel to each switch.

[0082] The inverter, rotating electric machine, and control device may be installed in a mobile body other than a vehicle, such as an aircraft or a ship. If the mobile body is an aircraft, the rotating electric machine serves as a power source for the aircraft's flight, and if the mobile body is a ship, the rotating electric machine serves as a power source for the ship's navigation. Furthermore, the inverter, rotating electric machine, and control device may be installed in a mobile body other than a vehicle.

[0083] The control device and 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 device and 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 device and 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 in a computer-readable non-transitory tangible recording medium as instructions executed by a computer.

[0084] 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. An inverter control device (50) applied to a system (200) including a rotating electric machine (20) having an armature winding (23U-23W) wound around an armature core (22), and an inverter (30) electrically connecting the armature winding and a power storage unit (10), the inverter control device comprising: a determination unit (67) that determines whether or not there is a temperature increase request for a temperature increase target (10); and a setting unit (65) that sets a switching mode of the inverter, wherein when it is determined that there is a temperature increase request, the setting unit performs a change process to change the switching mode so as to increase a voltage component included in a line voltage of the armature winding that varies at the switching frequency of the inverter compared to when it is determined that there is no temperature increase request.

2. The inverter control device according to claim 1, wherein the setting unit sets the switching mode by PWM processing based on a comparison of the magnitude of three-phase modulated waves (Dutyu, Dutyv, Dutyw) whose phases are shifted by 120 degrees in electrical angle with a carrier signal; if it is determined that there is no temperature increase request, it performs PWM processing based on a comparison of the magnitude of the modulated waves of the three phases with a common carrier signal (SgC); and if it is determined that there is a temperature increase request, in the change processing, it uses a carrier signal that is phase-shifted with respect to the carrier signal that is compared with the modulated waves of the remaining phases as the carrier signal to be compared with the modulated waves of some of the three phases.

3. The inverter control device according to claim 2, wherein the setting unit shifts the phases of the carrier signals (SgU, SgV, SgW) to be compared with the three-phase modulated waves by 120 degrees in electrical angle in the change process.

4. The inverter control device according to claim 2, wherein the setting unit uses, in the change process, as a carrier signal (SgV) to be compared with the modulated wave of one of the three phases, a carrier signal whose phase is shifted by 180 degrees in electrical angle from the carrier signals (SgU, SgW) to be compared with the modulated waves of the remaining two phases.

5. The inverter control device according to claim 4, wherein the setting unit, when determining that the temperature of the rotor (24) of the rotating electric machine is equal to or lower than a temperature threshold value (Trth), shifts the phase of the carrier signal to be compared with the modulated waves of three phases by 120 degrees in electrical angle in the change process; and, when determining that the temperature of the rotor exceeds the temperature threshold value, uses, in the change process, a carrier signal to be compared with the modulated waves of one of the three phases, the carrier signal whose phase is shifted by 180 degrees in electrical angle from the carrier signals to be compared with the modulated waves of the remaining two phases.

6. An inverter control device as described in claim 1 or 2, wherein when it is determined that there is a temperature increase request, the setting unit alternately switches between a first switching mode, which is the switching mode when it is determined that there is no temperature increase request, and a second switching mode, which is the switching mode changed by the change process.

7. The inverter control device according to claim 6, wherein the setting unit sets the first switching mode and the second switching mode in each specified period (TA), and the larger the temperature deviation (ΔT) obtained by subtracting the temperature of the object to be heated from the target temperature (Ttgt), the higher the proportion of the execution period (TH) of the second switching mode in the specified period.

8. The inverter control device according to claim 2, wherein the setting unit adjusts the phase difference of the carrier signals (SgU, SgV, SgW) to be compared with the three-phase modulated waves in the change process within a range greater than 0 degrees and less than or equal to 120 degrees.

9. The inverter control device according to claim 8, wherein the setting unit increases the phase difference in the change process as the temperature deviation (ΔT) obtained by subtracting the temperature of the object to be heated from the target temperature (Ttgt) increases.

10. An inverter control device according to any one of claims 1 to 5, 8 and 9, wherein the object to be heated includes the power storage unit, and the system is provided with a heat transfer unit (100, 101) that transfers heat generated in the rotating electric machine and the inverter to the object to be heated.

11. A program applied to a system (200) including a rotating electric machine (20) having an armature winding (23U-23W) wound around an armature core (22), and an inverter (30) electrically connecting the armature winding and a power storage unit (10), the program causes a processor (51) to execute a determination process for determining whether or not there is a temperature increase request for the object (10) to be heated, and a setting process for setting the switching mode of the inverter, and when it is determined in the setting process that there is a temperature increase request, the program performs a change process for changing the switching mode so as to increase the voltage component included in the line voltage of the armature winding that varies with the switching frequency of the inverter compared to when it is determined that there is no temperature increase request.

12. An inverter control method applied to a system (200) including a rotating electric machine (20) having an armature winding (23U-23W) wound around an armature core (22), and an inverter (30) electrically connecting the armature winding and a power storage unit (10), the method comprising: a determination step of determining whether or not there is a temperature increase request for a temperature increase target (10); and a setting step of setting a switching mode of the inverter, wherein, when it is determined in the setting step that there is a temperature increase request, a change process is performed to change the switching mode so as to increase a voltage component included in a line voltage of the armature winding that varies at the switching frequency of the inverter, compared to when it is determined that there is no temperature increase request.

Images