Rotary electric machine control device

Abstract

To obtain a rotary electric machine control device which can appropriately adjust temperature balance between a power conversion circuit and a rotary electric machine.SOLUTION: A rotary electric machine control device comprises: a power conversion circuit which supplies current to a winding of a rotary electric machine by on / off control of a switching element on the basis of a designated carrier frequency; a power conversion circuit temperature detector; a rotary electric machine temperature detector; and a control unit which changes the carrier frequency on the basis of at least one of rising speed of the power conversion circuit temperature and rising speed of rotary electric machine temperature and performs on / off control of the switching element of the power conversion circuit on the basis of the changed carrier frequency.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a rotating electrical machine control device.

Background Art

[0002] A power conversion device is often used for controlling a rotating electrical machine applied to an electric vehicle such as a hybrid vehicle or an electric vehicle. As the power conversion device, there are an AC / DC converter (Alternate Current / Direct Current Converter) that converts AC power into DC power, an inverter that converts DC power into AC power, a DC / DC converter (Direct Current / Direct Current Converter) that changes the levels of the input voltage and the output voltage of DC power, and the like. These power conversion devices often have a configuration including semiconductor switching elements.

[0003] As an example of the power conversion device, an inverter mounted on an electric vehicle is used to control a rotating electrical machine by converting DC power output from a DC power source into desired AC power and supplying it to the rotating electrical machine. The inverter is composed of a switching circuit configured by combining switching elements, a control circuit for controlling the switching elements, a current sensor for detecting a current flowing through a load such as a rotating electrical machine, a capacitor for countermeasures against switching noise, and the like.

[0004] A power conversion circuit including a switching circuit and a capacitor is called a power conversion circuit. When controlling, for example, a three-phase synchronous rotating electrical machine, the power conversion circuit is provided with a switching circuit in each of the upper arms (positive electrode side arms) and the lower arms (negative electrode side arms) of three phases (U phase, V phase, W phase).

[0005] By sequentially turning on and off the switching elements provided in each phase of the power conversion circuit, AC power with phases different from each other by 120 degrees is supplied to each phase of the rotating electrical machine to drive the rotating electrical machine. Since the temperature rise due to such driving causes shortening of the life of in-vehicle electrical components, it is necessary to suppress the temperature rise. Suppressing the temperature rise eliminates the need for additional installation of a cooling mechanism and contributes to reducing the size and weight of the product.

[0006] For preventing failures due to temperature rise of the power conversion circuit and the rotating electrical machine and miniaturizing the product, a control technique is disclosed which changes the carrier frequency of the control of the switching element according to the temperatures of the power conversion circuit and the rotating electrical machine and adjusts the balance of the temperatures of the power conversion circuit and the rotating electrical machine. With respect to the change in the carrier frequency, the temperatures of the power conversion circuit and the rotating electrical machine are in a trade-off relationship. From this, it is possible to control the balance of the temperatures of the power conversion circuit and the rotating electrical machine by changing the carrier frequency (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] The losses and temperature of the power conversion circuit strongly depend on the input voltage and output current. And the losses and temperature of the rotating electrical machine depend on the torque and rotational speed. In the application of the rotating electrical machine control device to an electric vehicle, the ranges taken by the input voltage, output current, torque, and rotational speed are very wide. Therefore, the balance of the losses and temperatures of the power conversion circuit and the rotating electrical machine varies greatly depending on the operating state of the electric vehicle.

[0009] Patent Document 1 describes control for determining whether the temperature of a power conversion circuit and the temperature of a rotating electrical machine are equal to or higher than a predetermined threshold value, and changing the carrier frequency of switching control. However, the temperature of the power conversion circuit or the rotating electrical machine transiently changes with a delay with respect to the loss. The timing of reaching the limit temperature of each component is affected by the loss value at each time point and the heat capacity specific to the component. Therefore, it is difficult to achieve temperature balance by comparing only the instantaneous value of the temperature of each component with the threshold value. The fact that the change in the temperature of each component varies greatly depending on the operating state of the vehicle also contributes to this difficulty.

[0010] The present disclosure proposes a technique for solving the above problems. An object of the present disclosure is to obtain a rotating electrical machine control device that can appropriately adjust the temperature balance between a power conversion circuit and a rotating electrical machine by determining the carrier frequency of switching control from the temperature increase rate of at least one of the power conversion circuit and the rotating electrical machine.

Means for Solving the Problems

[0011] The rotating electrical machine control device according to the present disclosure includes a power conversion circuit having a plurality of switching elements and supplying current to the windings of a rotating electrical machine by on / off controlling the switching elements based on a specified carrier frequency, a power conversion circuit temperature detector that detects the temperature of the power conversion circuit, a rotating electrical machine temperature detector that detects the temperature of the rotating electrical machine, and a control unit that changes the carrier frequency based on at least one of the temperature increase rate of the power conversion circuit detected by the power conversion circuit temperature detector and the temperature increase rate of the rotating electrical machine detected by the rotating electrical machine temperature detector, and performs on / off control of the switching elements of the power conversion circuit based on the changed carrier frequency.

Advantages of the Invention

[0012] According to the present disclosure, by determining the carrier frequency of switching control from the temperature rise rate of at least one of the power conversion circuit and the rotating electrical machine, a rotating electrical machine control device capable of appropriately adjusting the temperature balance between the power conversion circuit and the rotating electrical machine can be obtained. As a result, it is possible to determine a carrier frequency that takes an appropriate temperature balance in response to fluctuations in the operating conditions of the rotating electrical machine and transient changes in the temperatures of the respective components, contributing to the reduction in size and weight of the rotating electrical machine control device and the rotating electrical machine.

Brief Description of the Drawings

[0013]

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Embodiments for Carrying Out the Invention

[0014] Hereinafter, preferred embodiments of a rotating electrical machine control device according to the present disclosure will be described with reference to the drawings. In each figure, the same or corresponding parts are denoted by the same reference numerals, and duplicate explanations are omitted.

[0015] 1. Embodiment 1 <Configuration of Rotating Electrical Machine Control Device> FIG. 1 is a configuration diagram of a rotating electrical machine control device 1 according to Embodiment 1. The rotating electrical machine control device 1 may be used in an electric vehicle such as an electric vehicle or a plug-in hybrid vehicle. It is possible to assume a rotating electrical machine control device 1 for AC driving a rotating electrical machine 8 serving as a load using a power source 7 such as a battery as a power source.

[0016] The rotating electrical machine 8 is a concept including an electric motor (motor) and a generator (generator). The rotating electrical machine 8 connected to the rotating electrical machine control device 1 according to Embodiment 1 may be read as an electric motor or a generator. A rotating electrical machine having both functions of an electric motor and a generator can convert electric power into driving force for power running, and can also convert the driving force into electric power in the same structure for regenerative operation. The electric motor and the generator basically have the same structure, and both can perform power running and regenerative operation. In FIG. 1, the rotating electrical machine 8 is described as a three-phase AC rotating electrical machine, but a two-phase or a rotating electrical machine having a phase number more than three may be used. The rotating electrical machine 8 may be a synchronous motor or a synchronous generator having a magnet.

[0017] The rotating electrical machine control device 1 includes a power conversion circuit 2, a control unit 3, a current detector 4, a power conversion circuit temperature detector 5, a rotating electrical machine temperature detector 6, and a rotation angle detector 9. The rotating electrical machine control device 1 and the rotating electrical machine 8 constitute a rotating electrical machine device 100. The control unit 3 includes a carrier frequency calculation unit 22, a determination unit 15, and a temperature rise rate calculation unit 17. The control unit 3 controls the switching elements incorporated in the power conversion circuit 2 to control the three-phase phase currents flowing through the rotating electrical machine 8.

[0018] The current detector 4 detects the three-phase phase currents flowing between the power conversion circuit 2 and the rotating electrical machine 8. The rotating electrical machine control device 1 is provided with a U-phase current detector 4 that detects a U-phase current detection value I_U, a V-phase current detector 4 that detects a V-phase current detection value I_V, and a W-phase current detector 4 that detects a W-phase current detection value I_W. The current detector 4 may be a current sensor using a shunt resistor, a Hall element, or the like.

[0019] The rotation angle detector 9 outputs a rotation angle detection value RA of the drive shaft of the rotating electrical machine 8. The rotation angle detector 9 may be a Hall element, a resolver type detector, or a power generation type rotation detector.

[0020] The power conversion circuit temperature detector 5 and the rotating electrical machine temperature detector 6 may be temperature sensors using a thermistor, a thermocouple, a temperature detection diode, etc. The power conversion circuit temperature detector 5 detects the temperature of the switching element built in the power conversion circuit 2 and outputs power conversion circuit temperature information TI_PC. The power conversion circuit temperature detector 5 is not limited to this, and may also detect the temperature of a capacitor, a semiconductor module, etc. built in the power conversion circuit 2. It is sufficient if the temperature representing the temperature of the power conversion circuit 2 can be obtained.

[0021] The rotating electrical machine temperature detector 6 detects the temperature of the magnet built in the rotating electrical machine 8 and outputs rotating electrical machine temperature information TI_ERM. The rotating electrical machine temperature detector 6 is not limited to this, and may also detect the temperature of other components built in the rotating electrical machine 8. For example, it may also detect the temperature of a core (iron core) formed of laminated steel plates, a winding (coil) through which current flows to form a magnetic field, etc. It is sufficient if the temperature representing the temperature of the rotating electrical machine 8 can be obtained.

[0022] <Hardware Configuration of the Control Unit> FIG. 2 is a hardware configuration diagram of the control unit 3 of the rotating electrical machine control device 1 according to Embodiment 1. In the present embodiment, the control unit 3 is a control device that controls the rotating electrical machine control device 1. Each function of the control unit 3 is realized by a processing circuit provided in the control unit 3. Specifically, the control unit 3 includes, as a processing circuit, an arithmetic processing device 90 (computer) such as a CPU (Central Processing Unit), a storage device 91 that exchanges data with the arithmetic processing device 90, an input circuit 92 that inputs an external signal to the arithmetic processing device 90, and an output circuit 93 that outputs a signal from the arithmetic processing device 90 to the outside.

[0023] As the arithmetic processing unit 90, an ASIC (Application Specific Integrated Circuit), an IC (Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), various logic circuits, various signal processing circuits, etc. may be provided. Also, as the arithmetic processing unit 90, a plurality of the same type or different types may be provided, and each process may be executed in a shared manner. As the storage device 91, a RAM (Random Access Memory) configured to be able to read and write data from the arithmetic processing unit 90, a ROM (Read only Memory) configured to be able to read data from the arithmetic processing unit 90, etc. are provided. The input circuit 92 includes a current detector 4, a power conversion circuit temperature detector 5, a rotating electrical machine temperature detector 6, and a rotation angle detector 9, and various sensors and switches are connected thereto, and it includes an interface circuit such as an AD conversion unit and an input circuit that input the output signals of these sensors and switches to the arithmetic processing unit 90. The output circuit 93 includes switching elements 71 to 76, and electrical loads such as switching elements and actuators are connected thereto, and it includes an interface circuit such as a drive circuit and a communication circuit that convert and output the output signals from the arithmetic processing unit 90 to these electrical loads.

[0024] Each function provided in the control unit 3 is realized by the arithmetic processing unit 90 executing software (program) stored in a storage device 91 such as a ROM and cooperating with other hardware of the control unit 3 such as the storage device 91, the input circuit 92, and the output circuit 93. Note that setting data such as threshold values and determination values used by the control unit 3 are stored in the storage device 91 such as a ROM as part of the software (program).

[0025] Each function mounted inside the control unit 3 may be composed of software modules, or may be composed of a combination of software and hardware.

[0026] <Power conversion circuit> Figure 3 is a configuration diagram of the power conversion circuit 2 of the rotating electrical machine control device 1 according to Embodiment 1. The power conversion circuit 2 includes switching elements 71 to 76 and a capacitor 77.

[0027] The power conversion circuit 2 is connected to the positive electrode side of the power supply 7 and includes a positive electrode side switching element having a diode on the positive electrode side connected in antiparallel, and a negative electrode side switching element connected to the negative electrode side of the power supply 7 and having a diode on the negative electrode side connected in antiparallel. The positive electrode side switching element and the negative electrode side switching element are connected in series, and the winding of the rotating electrical machine 8 is connected to the connection point to form a leg. The switching elements 71 and 72, the switching elements 73 and 74, and the switching elements 75 and 76 respectively form three sets of legs in which the positive electrode side (upper stage side) switching element and the negative electrode side (lower stage side) switching element are connected in series, and are connected in parallel to the power supply 7.

[0028] The midpoint of the switching elements 71 and 72 is connected to the U-phase winding of the rotating electrical machine 8, the midpoint of the switching elements 73 and 74 is connected to the V-phase winding of the rotating electrical machine 8, and the midpoint of the switching elements 75 and 76 is connected to the W-phase winding of the rotating electrical machine 8.

[0029] In FIG. 3, the switching elements 71 to 76 are each a semiconductor. The switching elements 71 to 76 are composed of, for example, an IGBT (Insulated Gate Bipolar Transistor) and a diode connected in antiparallel between the emitter and collector of the IGBT. Note that the type and number of the switching elements are not limited to this. In addition to the combination of the IGBT and the diode connected in reverse, a MOSFET (Metal oxide Semiconductor Field Effect Transistor) having a parasitic diode built in between the source and drain, a SiC-MOSFET using SiC (Silicon Carbide), etc. may be used singly or in plurality as the switching element.

[0030] In order to control the rotating electrical machine 8 to an arbitrary output, the control unit 3 of the rotating electrical machine control device 1 performs switching control on the switching elements 71 to 76. In the switching control, the switching elements 71 to 76 are turned on and off at high speed. The control unit 3 generates a switching signal based on the set carrier frequency and outputs the switching signal to the power conversion circuit 2. The power conversion circuit 2 generates arbitrary AC power from DC power according to the input switching signal and controls the rotating electrical machine 8.

[0031] When the switching control is carried out, losses occur in the respective components of the power conversion circuit 2 and the rotating electrical machine 8, and the temperature rises. The temperature rise due to the switching control causes shortening of the life of in-vehicle electrical components and occurrence of failures, so it is necessary to suppress the temperature rise within an acceptable range. For this purpose, the power conversion circuit temperature detector 5 outputs power conversion circuit temperature information TI_PC. The rotating electrical machine temperature detector 6 outputs rotating electrical machine temperature information TI_ERM. Suppressing the temperature rise of the power conversion circuit 2 and the rotating electrical machine 8 eliminates the need for additional installation of a cooling mechanism and also contributes to reducing the size and weight of the product.

[0032] <Functions of the control unit> FIG. 4 is a functional block diagram of the control unit 3 of the rotating electrical machine control device 1 according to Embodiment 1. The control unit 3 receives power conversion circuit temperature information TI_PC from the power conversion circuit temperature detector 5 and receives rotating electrical machine temperature information TI_ERM from the rotating electrical machine temperature detector 6. Then, the power conversion circuit temperature threshold value TTH_PC and the rotating electrical machine temperature threshold value TTH_ERM are read as values described in software. The determination unit 15 outputs a control determination value JD_CTR according to the comparison result between the power conversion circuit temperature information TI_PC and the power conversion circuit temperature threshold value TTH_PC and the comparison result between the rotating electrical machine temperature information TI_ERM and the rotating electrical machine temperature threshold value TTH_ERM. The control determination value JD_CTR indicates an instruction to switch the method for calculating the carrier frequency to the carrier frequency calculation unit 22.

[0033] The temperature rise rate calculation unit 17 inputs the power conversion circuit temperature information TI_PC and the rotating electrical machine temperature information TI_ERM. Then, the temperature rise rate calculation unit 17 calculates the power conversion circuit temperature rise rate VT_PC and the rotating electrical machine temperature rise rate VT_ERM from these inputs.

[0034] The carrier frequency calculation unit 22 reads out the power conversion circuit limit temperature TL_PC and the rotating electrical machine limit temperature TL_ERM as values described in software. Then, the carrier frequency is calculated or updated by a calculation method based on the control determination value JD_CTR instructed from the determination unit 15. The carrier frequency calculation unit 22 calculates or updates the carrier frequency FRQ_C by using, as input values, the power conversion circuit temperature information TI_PC and the rotating electrical machine temperature information TI_ERM input from the outside, the power conversion circuit temperature rise rate VT_PC, the rotating electrical machine temperature rise rate VT_ERM, and the power conversion circuit limit temperature TL_PC and the rotating electrical machine limit temperature TL_ERM read from the software.

[0035] <Temperature rise rate calculation unit> FIG. 5 is a functional block diagram of the temperature rise rate calculation unit 17 of the rotating electrical machine control device 1 according to the first embodiment. The temperature rise rate calculation unit 17 includes a temperature holding unit 31 that holds the past power conversion circuit temperature information TI_PC before a predetermined time. Then, it includes an adder / subtractor 32 that takes the difference between the held power conversion circuit temperature information TI_PC and the current power conversion circuit temperature information TI_PC. Then, it includes a differential calculator 33 that performs time differentiation on the difference between the held power conversion circuit temperature information TI_PC and the current power conversion circuit temperature information TI_PC to calculate the power conversion circuit temperature rise rate VT_PC.

[0036] Further, similarly, the temperature rise rate calculation unit 17 includes a temperature holding unit 31 that holds past rotating electrical machine temperature information TI_ERM before a predetermined time. And it includes an adder / subtractor 32 that takes the difference between the held rotating electrical machine temperature information TI_ERM and the current rotating electrical machine temperature information TI_ERM. And it includes a differential calculator 33 that differentiates the difference between the held rotating electrical machine temperature information TI_ERM and the current rotating electrical machine temperature information TI_ERM with respect to time to calculate the rotating electrical machine temperature rise rate VT_ERM.

[0037] <Relationship between Carrier Frequency and Loss> FIG. 6 is a diagram showing the losses of the power conversion circuit 2 and the rotating electrical machine 8 with respect to the carrier frequency according to the first embodiment. FIG. 7 is a diagram showing the total losses of the power conversion circuit 2 and the rotating electrical machine 8 with respect to the carrier frequency.

[0038] Loss refers to energy loss, and due to loss, power is consumed and converted into heat. Loss thus indicates heat generation. Among the losses of the power conversion circuit 2, the losses related to the carrier frequency FRQ_C are the switching losses LS_SW of the switching elements 71 to 76 and the dielectric loss LS_DIE of the capacitor.

[0039] The switching loss LS_SW occurs during switching, so it increases as the carrier frequency FRQ_C increases. The dielectric loss LS_DIE occurs when an alternating electric field is applied to the dielectric. Here, the alternating electric field is applied by the carrier wave. As the carrier frequency increases, the harmonic components of the alternating electric field decrease, and the dielectric loss LS_DIE decreases.

[0040] Among the losses of the rotating electrical machine 8 related to the carrier frequency FRQ_C are the magnet loss LS_MGN due to the magnet which is a magnetic material and the core loss LS_COR of the core composed of electrical steel sheets. The magnet loss LS_MGN and the core loss LS_COR of the electrical steel sheets can be divided into hysteresis loss and eddy current loss respectively. The hysteresis loss is generated due to the hysteresis characteristics of the magnetic material, and the eddy current loss is generated due to the eddy current flowing through the magnetic material. The magnet loss LS_MGN and the core loss LS_COR of the electrical steel sheets depend on the frequency of the current applied to the rotating electrical machine 8. When the carrier frequency FRQ_C increases, the harmonic components of the current decrease and the losses become smaller.

[0041] From these facts, it can be understood that when the carrier frequency FRQ_C increases or decreases, the magnet loss LS_MGN of the rotating electrical machine 8, the core loss LS_COR of the electrical steel sheets of the rotating electrical machine 8, and the dielectric loss LS_DIE of the power conversion circuit 2 are in a trade-off relationship with respect to the switching loss LS_SW of the power conversion circuit. The sum of the above-mentioned switching loss LS_SW, magnet loss LS_MGN, core loss LS_COR, and dielectric loss LS_DIE is shown as the total loss LS_TOTAL as in FIG. 7. The loss curves shown in FIGS. 6 and 7 are examples and vary depending on the specifications, configurations, materials, and usage environments of the power conversion circuit 2 and the rotating electrical machine 8.

[0042] <Processing of the control unit> FIG. 8 is a first flowchart showing the processing of the control unit 3 of the rotating electrical machine control device 1 according to Embodiment 1. FIG. 9 is a second flowchart. The first flowchart describes steps S101 to S108. The second flowchart shows the continuation of the first flowchart and describes steps S110 to S116.

[0043] Figs. 8 and 9 are flowcharts showing the processes of calculating and updating the carrier frequency and outputting the switching signal of the control unit 3 of the rotating electrical machine control device 1 according to Embodiment 1. The processes shown in Figs. 8 and 9 are executed by the processing device of the control unit 3. The processes in Figs. 8 and 9 may be executed at predetermined intervals (for example, every 1 ms). Alternatively, instead of at predetermined intervals, they may be executed for each event such as for each predetermined traveling distance or for each communication. Or, they may be constantly executed in the main routine.

[0044] Fig. 10 is a diagram showing a power conversion circuit temperature-corresponding carrier frequency decrease map. Fig. 11 is a diagram showing a rotating electrical machine temperature-corresponding carrier frequency increase map. Fig. 12 is a diagram showing a limit temperature arrival time-corresponding carrier frequency increase / decrease map. Fig. 13 is a diagram showing the switching of carrier frequency calculation.

[0045] Starting the process, in step S101, the control unit 3 of the rotating electrical machine control device 1 acquires the detected values and generates each piece of information. As shown in Fig. 4, the control unit 3 acquires the power conversion circuit temperature information TI_PC detected by the power conversion circuit temperature detector 5 and the rotating electrical machine temperature information TI_ERM detected by the rotating electrical machine temperature detector 6. At this time, the necessary detected values such as the rotation angle detection value RA detected by the rotation angle detector 9 and the phase current detection value detected by the current detector 4, which are necessary for the control of the power conversion circuit 2, are also acquired.

[0046] Then, the power conversion circuit temperature threshold TTH_PC, the rotating electrical machine temperature threshold TTH_ERM, the power conversion circuit limit temperature TL_PC, and the rotating electrical machine limit temperature TL_ERM are read as the values described in the software. Also, other information necessary for the control of the power conversion circuit 2 is generated. The required torque, required current, required rotational speed, etc. for controlling the rotating electrical machine 8 may be generated or received from inside or outside the rotating electrical machine control device 1. Here, these processes are described as the generation of each piece of information.

[0047] In step S102, the carrier frequency FRQ_C under control is read out. Although not shown in FIGS. 8 and 9, when starting the power conversion circuit 2 and the rotating electrical machine 8, a switching signal is calculated based on the initial carrier frequency previously held by the control unit 3 and output to the power conversion circuit 2. Thereafter, the control unit 3 calculates and updates the carrier frequency based on various input information and the generated information.

[0048] In step S103, it is determined whether the power conversion circuit temperature information TI_PC is greater than the power conversion circuit temperature threshold TTH_PC. If TI_PC > TTH_PC (the determination is YES), the process proceeds to step S107. If TI_PC > TTH_PC is not satisfied (the determination is NO), the process proceeds to step S104.

[0049] In step S104, it is determined whether the rotating electrical machine temperature information TI_ERM is greater than the rotating electrical machine temperature threshold TTH_ERM. If TI_ERM > TTH_ERM (the determination is YES), the process proceeds to step S106. If TI_ERM > TTH_ERM is not satisfied (the determination is NO), the process proceeds to step S105.

[0050] Step S105 is the case where TI_PC ≤ TTH_PC and TI_ERM ≤ TTH_ERM, and it is in the region of part A in FIG. 13. At this time, the carrier frequency FRQ_C at which the total loss LS_TOTAL is minimized is calculated. Specifically, the carrier frequency FRQ_C at which the loss is minimized is calculated from the curve illustrated in FIG. 7. Thereafter, the process proceeds to step S116.

[0051] Step S106 is the case where TI_PC ≤ TTH_PC and TI_ERM > TTH_ERM, and it is in the region of part B in FIG. 13. FIG. 13 shows an example of dividing the operating region into temperature regions of part A, part B, part C, and part D according to whether the value of the power conversion circuit temperature information TI_PC is greater than the power conversion circuit temperature threshold TTH_PC and whether the value of the rotating electrical machine temperature information TI_ERM is greater than the rotating electrical machine temperature threshold TTH_ERM, and switching the calculation method (control method) of the carrier frequency FRQ_C.

[0052] At this time, the carrier frequency FRQ_C is increased and updated using the rotational electrical machine temperature-corresponding carrier frequency increase map shown in FIG. 11. FIG. 11 shows an example in which the frequency change amount ΔFRQ_C increases as the rotational electrical machine temperature information TI_ERM increases. The setting of the data in FIG. 11 is not limited to this, and the optimum value can be set by simulation and experiment. Then, the process proceeds to step S116.

[0053] In step S107, it is determined whether the rotational electrical machine temperature information TI_ERM is greater than the rotational electrical machine temperature threshold value TTH_ERM. If TI_ERM > TTH_ERM (the determination is YES), the process proceeds to step S110. If TI_ERM > TTH_ERM is not satisfied (the determination is NO), the process proceeds to step S108.

[0054] Step S108 is a case where TI_PC > TTH_PC and TI_ERM ≤ TTH_ERM, and it is in the region of part C in FIG. 13. At this time, the carrier frequency FRQ_C is decreased and updated using the power conversion circuit temperature-corresponding carrier frequency decrease map shown in FIG. 10. FIG. 10 shows an example in which the frequency change amount ΔFRQ_C decreases as the power conversion circuit temperature information TI_PC increases. The setting of the data in FIG. 10 is not limited to this, and the optimum value can be set by simulation and experiment. Then, the process proceeds to step S116.

[0055] Step S110 is a case where TI_ERM > TTH_ERM and TI_ERM > TTH_ERM, and it is in the region of part D in FIG. 13. At this time, the power conversion circuit temperature increase rate VT_PC and the rotational electrical machine temperature increase rate VT_ERM are calculated.

[0056] Furthermore, the power conversion circuit limit temperature arrival time PL_PC is calculated by dividing the difference between the power conversion circuit limit temperature TL_PC and the current power conversion circuit temperature information TI_PC by the power conversion circuit temperature increase rate VT_PC. The calculation formula is shown in Equation (1).

[0057] PL_PC = (TL_PC - TI_PC) / VT_PC (1) Also, by dividing the difference between the rotational electric machine limit temperature TL_ERM and the current rotational electric machine temperature information TI_ERM by the rotational electric machine temperature rise rate VT_ERM, the rotational electric machine limit temperature arrival time PL_ERM is calculated. The calculation formula is shown in Equation (2).

[0058] PL_ERM = (TL_ERM - TI_ERM) / VT_ERM (2) Here, the rotational electric machine limit temperature arrival time PL_ERM is subtracted from the power conversion circuit limit temperature arrival time PL_PC to obtain the limit temperature arrival time difference ΔPL. The calculation formula is shown in Equation (3).

[0059] ΔPL = PL_PC - PL_ERM (3) After calculating the above, proceed to step S111.

[0060] In step S111, it is determined whether the absolute value of the limit temperature arrival time difference ΔPL is greater than the limit temperature arrival time difference determination value ΔPLTH. If |ΔPL| > ΔPLTH (the determination is YES), proceed to step S112. If |ΔPL| > ΔPLTH is not satisfied (the determination is NO), proceed to step S115.

[0061] Step S112 is the case where the time difference between the power conversion circuit limit temperature arrival time PL_PC and the rotational electric machine limit temperature arrival time PL_ERM is greater than the limit temperature arrival time difference determination value ΔPLTH. That is, it indicates a state where the margin until the limit temperatures of the power conversion circuit 2 and the rotational electric machine 8 is biased to one side and the temperature margin is not balanced. At this time, it is determined whether the power conversion circuit limit temperature arrival time PL_PC is longer than the rotational electric machine limit temperature arrival time PL_ERM. If PL_PC > PL_ERM (the determination is YES), proceed to step S113. If PL_PC > PL_ERM is not satisfied (the determination is NO), proceed to step S114.

[0062] In step S113, using the carrier frequency increase / decrease map corresponding to the limit temperature arrival time shown in FIG. 12, the increment of the carrier frequency is calculated and the carrier frequency FRQ_C is updated. By doing this, the temperature load on the power conversion circuit 2 with a margin until the limit temperature can be increased, and the temperature balance with the rotating electrical machine 8 without a margin until the limit temperature can be achieved.

[0063] FIG. 12 shows an example of the carrier frequency increase / decrease map data corresponding to the limit temperature arrival time from -4 to +4 (unit: Hz). When the processes shown in FIGS. 8 and 9 are executed every 1 ms, in the example of the map data in FIG. 12, the carrier frequency is increased or decreased in the range from -4 Hz / ms to +4 Hz / ms. The data is set according to the power conversion circuit limit temperature arrival time PL_PC and the rotating electrical machine limit temperature arrival time PL_ERM. The setting of the data is not limited to this, and the optimal value can be set by simulation and experiment. After the update of the carrier frequency FRQ_C, the process proceeds to step S116.

[0064] In step S114, using the carrier frequency increase / decrease map corresponding to the limit temperature arrival time shown in FIG. 12, the decrement of the carrier frequency is calculated and the carrier frequency FRQ_C is updated. By doing this, the temperature load on the rotating electrical machine 8 with a margin until the limit temperature can be increased, and the temperature balance with the power conversion circuit 2 without a margin until the limit temperature can be achieved. Then, the process proceeds to step S116.

[0065] Step S115 is a case where the absolute value of the limit temperature arrival time difference ΔPL is less than or equal to the limit temperature arrival time difference determination value ΔPLTH, and the difference between the power conversion circuit limit temperature arrival time PL_PC and the rotating electrical machine limit temperature arrival time PL_ERM is small. At this time, it indicates that the margin until reaching the limit temperature is almost the same for the power conversion circuit 2 and the rotating electrical machine 8 and the balance is achieved. In this case, it is determined to maintain the current carrier frequency FRQ_C. Then, the process proceeds to step S116.

[0066] In step S116, a switching signal based on a required torque, a required current, a required rotational speed, etc. is calculated using the calculated or updated carrier frequency FRQ_C. Then, the switching elements 71 to 76 of the power conversion circuit 2 are switched and controlled.

[0067] Although not shown in FIG. 9, when the power conversion circuit temperature information TI_PC exceeds the power conversion circuit limit temperature TL_PC, or when the rotating electrical machine temperature information TI_ERM exceeds the rotating electrical machine limit temperature TL_ERM, the drive current of the power conversion circuit 2 may be limited or cut off. By doing so, it is possible to prevent temperature overshoot that causes shortening of the life of in-vehicle electrical components and malfunctions.

[0068] As described above, by switching the method of calculating and updating the carrier frequency FRQ_C, the rotation electrical machine control device 1 can be controlled while taking the temperature balance between the power conversion circuit 2 and the rotating electrical machine 8. Since the temperatures of the power conversion circuit 2 and the rotating electrical machine 8 can be controlled while taking a balance within the range up to the power conversion circuit limit temperature TL_PC and the rotating electrical machine limit temperature TL_ERM, it is possible to expand the operable regions of the power conversion circuit 2 and the rotating electrical machine 8, prevent temperature overshoot, and appropriately control the rotation electrical machine control device 1.

[0069] By determining the carrier frequency FRQ_C of the switching control from the temperature increase rate of at least one of the power conversion circuit 2 and the rotating electrical machine 8, the temperature balance between the power conversion circuit 2 and the rotating electrical machine 8 can be appropriately adjusted. As a result, it is possible to determine the carrier frequency FRQ_C that takes an appropriate temperature balance in response to fluctuations in the operating conditions of the power conversion circuit 2 and the rotating electrical machine 8 and transient changes in the temperatures of the respective components. As a result, temperature overshoot of the power conversion circuit 2 and the rotating electrical machine 8 can be prevented. Suppression of temperature overshoot eliminates the need for additional installation of a cooling mechanism and can contribute to downsizing and weight reduction of the rotation electrical machine control device 1 and the rotating electrical machine 8.

[0070] <Time chart of temperature rise> FIG. 14 is a time chart showing an example of temperature rise of the switching element and the magnet according to Embodiment 1. The detected value T_SW of the switching element temperature is shown by a broken-line curve, and the detected value T_MGN of the magnet temperature is shown by a solid-line curve. Also, the limit temperature TL_SW of the switching element and the limit temperature TL_MGN of the magnet are shown by a two-dot chain line. And the temperature threshold value TTH_SW of the switching element and the temperature threshold value TTH_MGN of the magnet are shown by a broken line.

[0071] In the initial A period in which the temperatures of the switching element and the magnet rise, the detected value T_SW of the switching element temperature (corresponding to the power conversion circuit temperature information TI_PC) is equal to or lower than the temperature threshold value TTH_SW of the switching element (corresponding to the power conversion circuit temperature threshold value TTH_PC), and the detected value T_MGN of the magnet temperature (corresponding to the rotating electrical machine temperature information TI_ERM) is equal to or lower than the temperature threshold value TTH_MGN of the magnet (corresponding to the rotating electrical machine temperature threshold value TTH_ERM). Therefore, the A period corresponds to the region of part A in FIG. 13, and loss minimization control is implemented. Since both the semiconductor switching element and the magnet have a margin with respect to the limit temperature, the carrier frequency FRQ_C at which the total loss of the rotating electrical machine control device 1 and the rotating electrical machine 8 is minimized can be selected.

[0072] In the B period in which the temperatures of the switching element and the magnet further rise, the detected value T_SW of the switching element temperature (corresponding to the power conversion circuit temperature information TI_PC) is equal to or lower than the temperature threshold value TTH_SW of the switching element (corresponding to the power conversion circuit temperature threshold value TTH_PC) with a margin, but the detected value T_MGN of the magnet temperature (corresponding to the rotating electrical machine temperature information TI_ERM) is higher than the temperature threshold value TTH_MGN of the magnet (rotating electrical machine temperature threshold value TTH_ERM). It is necessary to take measures preferentially for the detected value T_MGN of the magnet temperature. Corresponding to the region of part B in FIG. 13, carrier frequency increase control corresponding to the rotating electrical machine temperature is implemented. Thereby, the carrier frequency FRQ_C is increased so that the loss of the magnet is reduced, and the temperature rise is moderated.

[0073] Here, the case where the detected magnet temperature value \(T_{MGN}\) exceeds the magnet temperature threshold value \(TTH_{MGN}\) first has been shown. However, actually, the case where the detected switching element temperature value \(T_{SW}\) exceeds the switching element temperature threshold value \(TTH_{SW}\) first can also be assumed.

[0074] In the C period in which the temperatures of the switching element and the magnet further rise, the detected switching element temperature value \(T_{SW}\) (corresponding to the power conversion circuit temperature information \(TI_{PC}\)) is also higher than the switching element temperature threshold value \(TTH_{SW}\) (corresponding to the power conversion circuit temperature threshold value \(TTH_{PC}\)). Corresponding to the region of the D part in FIG. 13, the carrier frequency increase / decrease control corresponding to the limit temperature arrival time is implemented.

[0075] The calculation method of the carrier frequency \(FRQ_C\) using the temperature rise rate is applied, and the limit temperature arrival time difference is calculated from the temperature rise rates of the semiconductor switching element and the magnet. The temperature balance between the semiconductor switching element and the magnet is adjusted, and the carrier frequency \(FRQ_C\) is adjusted so that the time difference for reaching the limit temperature is less than the limit temperature arrival time difference determination value \(\Delta PLTH\).

[0076] In this way, by providing the switching element temperature threshold value \(TTH_{SW}\) and the magnet temperature threshold value \(TTH_{MGN}\), while operating the power conversion circuit 2 and the rotating electrical machine 8 efficiently, it is possible to continue driving in a well-balanced manner up to near the limit temperature of each component when the temperature rises.

[0077] 2. Embodiment 2 <Function of the control unit> FIG. 15 is a functional block diagram of the control unit 3 of the rotating electrical machine control device 1 according to Embodiment 2. In the rotating electrical machine control device 1 according to Embodiment 1, in the region shown in the D part of FIG. 13, the carrier frequency \(FRQ_C\) is determined based on the temperature rise rates of the power conversion circuit 2 and the rotating electrical machine 8. In Embodiment 2, a method for determining the carrier frequency \(FRQ_C\) based only on the temperature rise rate of the rotating electrical machine 8 in this region will be described.

[0078] Consider the case where the margins to the limit temperatures of the power conversion circuit 2 and the rotating electrical machine 8 are significantly different. For example, for the power conversion circuit 2, consider the case where the power conversion circuit temperature information TI_PC does not reach the power conversion circuit limit temperature TL_PC over the entire frequency range of the carrier frequency FRQ_C in the control execution region.

[0079] Due to the improvement of the heat resistance performance of the switching element and the expansion of the cooling structure, it may be possible to use the carrier frequency FRQ_C over the entire frequency range for the power conversion circuit 2. Even in this case, control based on minimizing losses in consideration of power efficiency should be fundamental. This is because in an electric vehicle, an improvement in power efficiency leads to an increase in the cruising range and a reduction in fuel consumption (charging cost).

[0080] As shown in FIG. 15, in the control unit 3 according to the second embodiment, the temperature rise rate calculation unit 17 inputs the rotating electrical machine temperature information TI_ERM and calculates the rotating electrical machine temperature rise rate VT_ERM. The power conversion circuit temperature threshold TTH_PC, the rotating electrical machine temperature threshold TTH_ERM, the power conversion circuit limit temperature TL_PC, the rotating electrical machine limit temperature TL_ERM, and the rotating electrical machine temperature rise rate threshold VTTH_ERM are read as values described in software.

[0081] The determination unit 15 outputs a control determination value JD_CTR to the carrier frequency calculation unit 22 as an instruction to switch the method for calculating the carrier frequency. The determination unit 15 according to the second embodiment outputs an instruction to update the carrier frequency FRQ_C using the rotating electrical machine temperature rise rate VT_ERM in the region shown in part D of FIG. 13.

[0082] <Processing of the control unit> FIG. 16 is a second flowchart showing the processing of the control unit 3 of the rotating electrical machine control device 1 according to Embodiment 2, and shows the continuation of the first flowchart. The first flowchart directly uses the first flowchart according to Embodiment 1 in FIG. 8. The processing shown in FIGS. 8 and 16 is executed by the processing device of the control unit 3. The processing in FIGS. 8 and 16 may be executed every predetermined time (for example, every 1 ms). Alternatively, instead of every predetermined time, it may be executed for every predetermined running distance, every time communication is performed, or for each event such as this. Alternatively, it may be constantly executed in the main routine.

[0083] FIG. 17 is a diagram showing a carrier frequency increase map corresponding to the rotating electrical machine temperature rise rate according to Embodiment 2. FIG. 18 is a diagram showing the switching of carrier frequency calculation according to Embodiment 2.

[0084] Only the second flowchart in FIG. 16 will be described. Similar to step S110 in FIG. 9, when TI_PC > TTH_PC and TI_ERM > TTH_ERM, the process proceeds to step S120 in FIG. 16. That is, it is the case of being in the region of part D in FIG. 18. In the regions of parts A, B, and C in FIG. 18, it is described in the processing of FIG. 8 and is the same as the processing of the control unit according to Embodiment 1.

[0085] In step S120, the rotating electrical machine temperature rise rate VT_ERM is calculated. The difference between the past rotating electrical machine temperature information TI_ERM before a predetermined time and the current rotating electrical machine temperature information TI_ERM is time-differentiated to calculate the rotating electrical machine temperature rise rate VT_ERM.

[0086] In step S121, it is determined whether the rotating electrical machine temperature rise rate VT_ERM is greater than the rotating electrical machine temperature rise rate threshold value VTTH_ERM. If VT_ERM > VTTH_ERM (the determination is YES), the process proceeds to step S122. If VT_ERM > VTTH_ERM is not satisfied (the determination is NO), the process proceeds to step S123.

[0087] Step S122 indicates a case where the rotational electrical machine temperature rise rate VT_ERM is high and it is necessary to slow down the temperature rise rate. In this case, the carrier frequency FRQ_C is increased and updated using the rotational electrical machine temperature rise rate - corresponding carrier frequency increase map shown in FIG. 17. FIG. 17 shows an example where the frequency change amount ΔFRQ_C increases as the rotational electrical machine temperature rise rate VT_ERM increases. The data settings in FIG. 17 are not limited to this, and the optimal values can be set through simulation and experiments. Then, it proceeds to step S116.

[0088] Step S123 indicates a case where the rotational electrical machine temperature rise rate VT_ERM is not high and it is not necessary to slow down the temperature rise rate. In this case, a decision is made to maintain the current carrier frequency FRQ_C. Then, it proceeds to step S116.

[0089] In step S116, a switching signal based on the required torque, required current, required rotational speed, etc. is calculated using the calculated or updated carrier frequency FRQ_C. Then, the switching elements 71 to 76 of the power conversion circuit 2 are switched and controlled.

[0090] Although not described in FIG. 16, when the power conversion circuit temperature information TI_PC exceeds the power conversion circuit limit temperature TL_PC, or when the rotational electrical machine temperature information TI_ERM exceeds the rotational electrical machine limit temperature TL_ERM, the drive current of the power conversion circuit 2 may be limited or cut off. By doing so, it is possible to prevent temperature over - rise that causes shortening of the lifespan of in - vehicle electrical components and malfunctions.

[0091] As described above, by switching the method of calculating and updating the carrier frequency FRQ_C, the rotational electrical machine control device 1 can be controlled while achieving a temperature balance between the power conversion circuit 2 and the rotational electrical machine 8. The temperature of the rotational electrical machine 8 can be controlled according to the rotational electrical machine temperature rise rate VT_ERM while achieving a balance within the range until it reaches the rotational electrical machine limit temperature TL_ERM. The rotational electrical machine control device 1 can be appropriately controlled while preventing temperature over - rise of the power conversion circuit 2 and the rotational electrical machine 8.

[0092] In FIG. 16, a control method of updating the carrier frequency FRQ_C in accordance with the rotating electrical machine temperature rise rate VT_ERM was described only in the region corresponding to part D of FIG. 18. However, this control method of updating the carrier frequency FRQ_C in accordance with the rotating electrical machine temperature rise rate VT_ERM may be extended to other regions. It may be extended to part B of FIG. 18. By doing so, the carrier frequency FRQ_C can be adjusted more quickly in accordance with the rotating electrical machine temperature rise rate VT_ERM, which is effective. It is also possible to appropriately respond even when the temperature transition of each component varies greatly depending on the operating state of the vehicle.

[0093] 3. Embodiment 3 <Functions of the control unit> FIG. 19 is a functional block diagram of the control unit 3 of the rotating electrical machine control device 1 according to Embodiment 3. In the rotating electrical machine control device 1 according to Embodiment 1, in the region shown in part D of FIG. 13, the carrier frequency FRQ_C was determined from the temperature rise rates of the power conversion circuit 2 and the rotating electrical machine 8 respectively. In Embodiment 3, a method of determining the carrier frequency FRQ_C based only on the temperature rise rate of the power conversion circuit 2 in this region will be described.

[0094] The switching elements 71 to 76 of the power conversion circuit 2 have a very small heat capacity compared to the magnet of the rotating electrical machine 8, the iron core composed of electromagnetic steel sheets, and the winding. For this reason, the time from when the power conversion circuit 2 is started until it heats up is short. Under this condition, if an attempt is made to simultaneously approach the limit temperatures of the power conversion circuit 2 and the rotating electrical machine 8, the carrier frequency FRQ_C is set to be small so as to extend the time to reach the limit temperature of the semiconductor switching element and shorten the time to reach the limit temperature of the rotating electrical machine 8. Then, it becomes difficult to balance the steady losses of the power conversion circuit 2 and the rotating electrical machine 8.

[0095] While considering the loss balance between the power conversion circuit 2 and the rotating electrical machine 8, rapid control when approaching the limit temperature is considered. Attention is paid to the power conversion circuit temperature rise rate VT_PC of the power conversion circuit 2 in which the temperature is rapidly controlled according to the operation of the carrier frequency FRQ_C. When approaching the limit temperature, it may be possible to calculate and update the carrier frequency FRQ_C based on the power conversion circuit temperature rise rate VT_PC.

[0096] As shown in FIG. 19, in the control unit 3 according to the third embodiment, the temperature rise rate calculation unit 17 inputs the power conversion circuit temperature information TI_PC and calculates the power conversion circuit temperature rise rate VT_PC. The power conversion circuit temperature threshold value TTH_PC, the rotating electrical machine temperature threshold value TTH_ERM, the power conversion circuit limit temperature TL_PC, the rotating electrical machine limit temperature TL_ERM, and the power conversion circuit temperature rise rate threshold value VTTH_PC are read as values described in software.

[0097] The determination unit 15 outputs a control determination value JD_CTR to the carrier frequency calculation unit 22 as an instruction to switch the method for calculating the carrier frequency. The determination unit 15 according to the third embodiment outputs an instruction to update the carrier frequency FRQ_C using the power conversion circuit temperature rise rate VT_PC in the region shown in part D of FIG. 13.

[0098] <Processing of the control unit> FIG. 20 is a second flowchart showing the processing of the control unit 3 of the rotating electrical machine control device 1 according to the third embodiment, and shows the continuation of the first flowchart. The first flowchart uses the first flowchart according to the first embodiment of FIG. 8 as it is. The processing shown in FIGS. 8 and 20 is executed by the processing device of the control unit 3. The processing in FIGS. 8 and 20 may be executed at predetermined time intervals (for example, every 1 ms). Alternatively, instead of at predetermined time intervals, it may be executed for each event such as every predetermined travel distance or every time communication is performed. Alternatively, it may be constantly executed in the main routine.

[0099] FIG. 21 is a diagram showing a carrier frequency reduction map corresponding to the power conversion circuit temperature rise rate according to Embodiment 3. FIG. 22 is a diagram showing the switching of carrier frequency calculation according to Embodiment 3.

[0100] Only the second flowchart of FIG. 20 will be described. Similar to step S110 in FIG. 9, when TI_PC>TTH_PC and TI_ERM>TTH_ERM, the process proceeds to step S120 in FIG. 20. That is, it is the case of being in the region of part D in FIG. 22. In the case of the regions of parts A, B, and C in FIG. 20, it is described in the process of FIG. 8 and is the same as the process of the control unit according to Embodiment 1.

[0101] In step S130, the power conversion circuit temperature rise rate VT_PC is calculated. The difference between the past power conversion circuit temperature information TI_PC before a predetermined time and the current power conversion circuit temperature information TI_PC is time-differentiated to calculate the power conversion circuit temperature rise rate VT_PC.

[0102] In step S131, it is determined whether the power conversion circuit temperature rise rate VT_PC is greater than the power conversion circuit temperature rise rate threshold value VTTH_PC. If VT_PC>VTTH_PC (the determination is YES), the process proceeds to step S132. If VT_PC>VTTH_PC is not satisfied (the determination is NO), the process proceeds to step S133.

[0103] Step S132 indicates the case where the power conversion circuit temperature rise rate VT_PC is high and it is necessary to slow down the temperature rise rate. In this case, using the carrier frequency reduction map corresponding to the power conversion circuit temperature rise rate shown in FIG. 21, the carrier frequency FRQ_C is decreased and updated. FIG. 21 shows an example in which the frequency change amount ΔFRQ_C decreases as the power conversion circuit temperature rise rate VT_PC increases. The setting of the data in FIG. 21 is not limited to this, and the optimum value can be set by simulation and experiment. Then, the process proceeds to step S116.

[0104] Step S133 indicates a case where the temperature rise rate VT_PC of the power conversion circuit is not high and there is no need to slow down the temperature rise rate. In this case, a decision is made to maintain the current carrier frequency FRQ_C. Then, the process proceeds to step S116.

[0105] In step S116, switching signals based on the required torque, required current, required rotational speed, etc. are calculated using the calculated or updated carrier frequency FRQ_C. Then, the switching elements 71 to 76 of the power conversion circuit 2 are switched and controlled.

[0106] Although not described in FIG. 20, when the power conversion circuit temperature information TI_PC exceeds the power conversion circuit limit temperature TL_PC, or when the rotating electrical machine temperature information TI_ERM exceeds the rotating electrical machine limit temperature TL_ERM, the drive current of the power conversion circuit 2 may be limited or cut off. By doing so, it is possible to prevent shortening of the life of in-vehicle electrical components and temperature overshoot that causes failures.

[0107] As described above, by switching the method of calculating and updating the carrier frequency FRQ_C, the rotation electrical machine control device 1 can be controlled while balancing the temperatures of the power conversion circuit 2 and the rotating electrical machine 8. The temperature of the power conversion circuit 2 can be controlled according to the temperature rise rate VT_PC of the power conversion circuit while achieving a balance within the range until it reaches the power conversion circuit limit temperature TL_PC. The rotation electrical machine control device 1 can be appropriately controlled while preventing temperature overshoot of the power conversion circuit 2 and the rotating electrical machine 8.

[0108] In FIG. 20, a control method for updating the carrier frequency FRQ_C in accordance with the power conversion circuit temperature rise rate VT_PC was described only for the region corresponding to part D of FIG. 22. However, this control method for updating the carrier frequency FRQ_C in accordance with the power conversion circuit temperature rise rate VT_PC may be extended to other regions. It may be extended to part C of FIG. 22. By doing so, the carrier frequency FRQ_C can be adjusted more quickly in accordance with the power conversion circuit temperature rise rate VT_PC, which is effective. It can also appropriately respond even when the temperature changes of each component vary greatly depending on the operating state of the vehicle.

[0109] 4. Embodiment 4 FIG. 23 is a functional block diagram of the control unit 3 of the rotating electrical machine control device 1 according to Embodiment 4. In the rotating electrical machine control device 1 according to Embodiments 1 to 3, it was described that the power conversion circuit temperature detector 5 detects the temperature of the switching element and outputs the power conversion circuit temperature information TI_PC. And the rotating electrical machine temperature detector 6 was described as detecting the temperature of the magnet built in the rotating electrical machine 8 and outputting the rotating electrical machine temperature information TI_ERM.

[0110] In the control unit 3 of FIG. 23, a temperature estimation unit 57 is provided. The temperature estimation unit 57 estimates the temperature of the power conversion circuit 2 and outputs the power conversion circuit temperature information TI_PC, and estimates the temperature of the rotating electrical machine 8 and outputs the rotating electrical machine temperature information TI_ERM.

[0111] The temperature estimation unit 57 inputs the U-phase current detection value I_U, V-phase current detection value I_V, and W-phase current detection value I_W output from the current detector 4, and the rotation angle detection value RA output from the rotation angle detector 9. Further, the temperature estimation unit 57 inputs at least one of the detection values such as the switching element temperature detection value T_SW, capacitor temperature detection value T_CP, and semiconductor module temperature detection value T_SCM output from the power conversion circuit temperature detector 5. And the temperature estimation unit 57 inputs at least one of the detection values such as the magnet temperature detection value T_MGN, core temperature detection value T_COR, and winding temperature detection value T_COIL output from the rotating electrical machine temperature detector 6.

[0112] The temperature estimation unit 57 estimates the temperatures of the power conversion circuit 2 and the rotating electrical machine 8 according to the input values, and outputs them as the power conversion circuit temperature information TI_PC and the rotating electrical machine temperature information TI_ERM. The temperature estimation method in the temperature estimation unit 57 is estimated using a thermal equivalent circuit.

[0113] The temperature estimation unit 57 holds a thermal equivalent circuit composed of thermal resistance and thermal capacitance in advance, with the detected values of the power conversion circuit temperature detector 5 and the rotating electrical machine temperature detector 6 as the reference temperatures, and estimates the temperature from the losses at each operating point. The losses at each operating point are calculated based on the input U-phase current detection value I_U, V-phase current detection value I_V, W-phase current detection value I_W, and rotation angle detection value RA. Thereby, when using the estimated values, the sensors of the power conversion circuit temperature detector 5 and the rotating electrical machine temperature detector 6 can be selectively attached to places where they are easy to attach, realizing miniaturization and cost reduction.

[0114] 5. Embodiment 5 FIG. 24 is a functional block diagram of the control unit 3 of the rotating electrical machine control device 1 according to Embodiment 5. In the control unit 3 of the rotating electrical machine control device 1 according to Embodiments 1 to 4, the determination unit 15 changes the calculation method of the carrier frequency FRQ_C using the power conversion circuit temperature threshold value TTH_PC and the rotating electrical machine temperature threshold value TTH_ERM.

[0115] In contrast, in Embodiment 5, the control unit 3 that calculates the carrier frequency FRQ_C without using the determination unit 15, the power conversion circuit temperature threshold value TTH_PC, and the rotating electrical machine temperature threshold value TTH_ERM will be described. The control unit 3 includes a temperature rise rate calculation unit 17 and a carrier frequency calculation unit 22. The carrier frequency calculation unit 22 calculates the carrier frequency FRQ_C from the power conversion circuit temperature rise rate VT_PC, the rotating electrical machine temperature rise rate VT_ERM, the power conversion circuit temperature information TI_PC, and the rotating electrical machine temperature information TI_ERM.

[0116] As a result, it is no longer necessary to pre-hold the power conversion circuit temperature threshold TTH_PC and the rotating electrical machine temperature threshold TTH_ERM, and the control unit 3 of the rotating electrical machine control device 1 can be implemented more easily. Also, since the power conversion circuit temperature threshold TTH_PC and the rotating electrical machine temperature threshold TTH_ERM are not provided, it is not necessary to determine whether to switch the calculation method of the carrier frequency FRQ_C, and high-speed calculation becomes possible. Therefore, it becomes possible to control the temperature with higher accuracy.

[0117] The calculation performed by the carrier frequency calculation unit 22 may be to execute the calculation described in Embodiments 1 to 3. That is, the calculation performed in the region of part D in the figures showing the switching of the carrier frequency calculation in FIGS. 13, 18, and 22 can be executed.

[0118] In the rotating electrical machine control device 1 according to Embodiments 1 to 5 above, the type of semiconductor of the switching element applied to the power conversion circuit 2 is not particularly limited. However, by using a wide bandgap semiconductor, it is possible to expect performance improvement. Examples of wide bandgap semiconductor elements include those formed of silicon carbide (SiC), gallium nitride (GaN)-based materials, or diamond (C).

[0119] The power conversion circuit 2 composed of switching elements formed of such a wide bandgap semiconductor has high breakdown voltage and low loss compared with the power conversion circuit 2 composed of switching elements formed of conventional silicon (Si), and has the characteristic that the carrier frequency FRQ_C can be driven up to a high frequency. Hereinafter, the power conversion circuit 2 composed of switching elements formed of a wide bandgap semiconductor is referred to as a wide bandgap power conversion circuit, and the power conversion circuit 2 composed of switching elements formed of silicon (Si) is referred to as a silicon power conversion circuit.

[0120] In the rotating electrical machine control device 1 using a wide-bandgap power conversion circuit, compared with the rotating electrical machine control device 1 using a silicon power conversion circuit, the range in which the carrier frequency FRQ_C can be controlled is widened, so that the temperature can be accurately controlled.

[0121] As described above, in the rotating electrical machine control device 1 according to Embodiments 1 to 5, by determining the carrier frequency FRQ_C in consideration of the temperature rise rate of the rotating electrical machine control device 1 or the rotating electrical machine 8, or both, the temperatures of the rotating electrical machine control device 1 and the rotating electrical machine 8 are controlled, and it becomes possible to appropriately use the rotating electrical machine control device 1 and the rotating electrical machine 8 up to the limit temperature at any operating point.

[0122] Although various exemplary embodiments and examples are described in the present disclosure, the various features, aspects, and functions described in one or more of the embodiments are not limited to the application of a specific embodiment, but are applicable to the embodiments alone or in various combinations. Therefore, countless modifications not illustrated are assumed within the scope of the disclosed technology. For example, it is assumed to include the case of deforming, adding, or omitting at least one component, and further the case of extracting at least one component and combining it with the components of other embodiments.

[0123] Hereinafter, aspects of the present disclosure will be collectively described as appendices.

[0124] (Appendix 1) A power conversion circuit having a plurality of switching elements and supplying current to the windings of a rotating electrical machine by on / off controlling the switching elements based on a specified carrier frequency, A power conversion circuit temperature detector for detecting the temperature of the power conversion circuit, A rotating electrical machine temperature detector for detecting the temperature of the rotating electrical machine, and A rotation electric machine control device comprising: a control unit that changes the carrier frequency based on at least one of the rate of increase in the power conversion circuit temperature detected by the power conversion circuit temperature detector and the rate of increase in the rotation electric machine temperature detected by the rotation electric machine temperature detector, and performs on / off control of the switching element of the power conversion circuit based on the changed carrier frequency. (Appendix 2) The control unit calculates a power conversion circuit limit temperature arrival time, which is the time until the power conversion circuit temperature reaches the power conversion circuit limit temperature, based on the power conversion circuit temperature, the rate of increase in the power conversion circuit temperature, and a predetermined power conversion circuit limit temperature; calculates a rotation electric machine limit temperature arrival time, which is the time until the rotation electric machine temperature reaches the rotation electric machine limit temperature, based on the rotation electric machine temperature, the rate of increase in the rotation electric machine temperature, and a predetermined rotation electric machine limit temperature; The rotation electric machine control device according to Appendix 1, wherein the carrier frequency is changed based on the difference between the power conversion circuit limit temperature arrival time and the rotation electric machine limit temperature arrival time. (Appendix 3) The control unit increases the carrier frequency when the power conversion circuit limit temperature arrival time is longer than the rotation electric machine limit temperature arrival time, and decreases the carrier frequency when the rotation electric machine limit temperature arrival time is longer than the power conversion circuit limit temperature arrival time. The rotation electric machine control device according to Appendix 2. (Appendix 4) The control unit switches the method of changing the carrier frequency when at least one of the cases where the power conversion circuit temperature is equal to or higher than a predetermined power conversion circuit temperature determination value and the rotation electric machine temperature is equal to or higher than a predetermined rotation electric machine temperature determination value occurs. The rotation electric machine control device according to any one of Appendices 1 to 3. (Appendix 5) The control unit decreases the carrier frequency when the power conversion circuit temperature is less than a predetermined power conversion circuit temperature determination value and the rotation electric machine temperature is equal to or higher than a predetermined rotation electric machine temperature determination value. The rotation electric machine control device according to any one of Appendices 1 to 4. (Appendix 6) The control unit increases the carrier frequency when the power conversion circuit temperature is equal to or higher than a predetermined power conversion circuit temperature determination value and the rotating electrical machine temperature is lower than a predetermined rotating electrical machine temperature determination value. The rotating electrical machine control device according to any one of Appendices 1 to 5. (Appendix 7) The control unit decreases the carrier frequency in response to an increase in the rising rate of the power conversion circuit temperature, and increases the carrier frequency in response to an increase in the rising rate of the rotating electrical machine temperature. The rotating electrical machine control device according to Appendix 1. (Appendix 8) The control unit calculates the rising rate of the power conversion circuit temperature from the difference between the power conversion circuit temperature before a predetermined time and the current power conversion circuit temperature, and calculates the rising rate of the rotating electrical machine temperature from the difference between the rotating electrical machine temperature before the time and the current rotating electrical machine temperature. The rotating electrical machine control device according to any one of Appendices 1 to 7. (Appendix 9) A first temperature detector is disposed on the magnet, winding, or iron core of the rotating electrical machine, a second temperature detector is disposed on the switching element, capacitor, or semiconductor module of the power conversion circuit, and the control unit estimates the rotating electrical machine temperature based on the temperature detected by the first temperature detector and estimates the power conversion circuit temperature based on the temperature detected by the second temperature detector. The rotating electrical machine control device according to any one of Appendices 1 to 8. (Appendix 10) A first temperature detector is disposed on the switching element of the power conversion circuit, and the control unit estimates the power conversion circuit temperature based on the temperature detected by the first temperature detector. The rotating electrical machine control device according to Appendix 9. (Appendix 11) A first temperature detector is disposed on the capacitor of the power conversion circuit, and the control unit estimates the power conversion circuit temperature based on the temperature detected by the first temperature detector. The rotating electrical machine control device according to Appendix 9. (Appendix 12) A first temperature detector is arranged on the semiconductor module of the power conversion circuit, and the control unit is the rotating electrical machine control device according to Appendix 9 that estimates the temperature of the power conversion circuit based on the temperature detected by the first temperature detector. (Appendix 13) A second temperature detector is arranged on the iron core of the rotating electrical machine, and the control unit is the rotating electrical machine control device according to any one of Appendices 9 to 12 that estimates the temperature of the rotating electrical machine based on the temperature detected by the second temperature detector. (Appendix 14) A second temperature detector is arranged on the magnet of the rotating electrical machine, and the control unit is the rotating electrical machine control device according to any one of Appendices 9 to 12 that estimates the temperature of the rotating electrical machine based on the temperature detected by the second temperature detector. (Appendix 15) A second temperature detector is arranged on the winding of the rotating electrical machine, and the control unit is the rotating electrical machine control device according to any one of Appendices 9 to 12 that estimates the temperature of the rotating electrical machine based on the temperature detected by the second temperature detector. (Appendix 16) The control unit, estimates the temperature of the rotating electrical machine based on the temperature detected by the first temperature detector, the phase current value detected by a current detector that detects the current supplied to the winding of the rotating electrical machine, and the rotation angle detected by a rotation angle detector provided on the rotating electrical machine, and is the rotating electrical machine control device according to any one of Appendices 9 to 15 that estimates the temperature of the power conversion circuit based on the temperature detected by the second temperature detector, the phase current value detected by the current detector, and the rotation angle detected by the rotation angle detector. (Appendix 17) The switching element of the power conversion circuit is formed of a wide-gap semiconductor, and it is the rotating electrical machine control device according to any one of Appendices 1 to 16. (Appendix 18) The wide-gap semiconductor of the power conversion circuit is a rotating electrical machine control device according to Appendix 17 containing silicon carbide, gallium nitride-based material, or diamond.

Explanation of Signs

[0125] 1 Rotating electrical machine control device, 2 Power conversion circuit, 3 Control unit, 4 Current detector, 5 Power conversion circuit temperature detector, 6 Rotating electrical machine temperature detector, 8 Rotating electrical machine, 9 Rotation angle detector, 71, 72, 73, 74, 75, 76 Switching element, 77 Capacitor

Claims

1. A power conversion circuit having a plurality of switching elements, and supplying current to a winding of a rotating electrical machine by on / off controlling the switching elements based on a specified carrier frequency, a power conversion circuit temperature detector for detecting the temperature of the power conversion circuit, a rotating electrical machine temperature detector for detecting the temperature of the rotating electrical machine, and a control unit that changes the carrier frequency based on at least one of the rate of increase in the power conversion circuit temperature detected by the power conversion circuit temperature detector and the rate of increase in the rotating electrical machine temperature detected by the rotating electrical machine temperature detector, and performs on / off control of the switching elements of the power conversion circuit based on the changed carrier frequency. A rotating electrical machine control device comprising the above components.

2. The control unit, calculates a power conversion circuit limit temperature arrival time, which is the time until the power conversion circuit temperature reaches a predetermined power conversion circuit limit temperature, based on the power conversion circuit temperature, the rate of increase in the power conversion circuit temperature, and a predetermined power conversion circuit limit temperature, calculates a rotating electrical machine limit temperature arrival time, which is the time until the rotating electrical machine temperature reaches a predetermined rotating electrical machine limit temperature, based on the rotating electrical machine temperature, the rate of increase in the rotating electrical machine temperature, and a predetermined rotating electrical machine limit temperature, The rotating electrical machine control device according to claim 1, wherein the carrier frequency is changed based on the difference between the power conversion circuit limit temperature arrival time and the rotating electrical machine limit temperature arrival time.

3. The control unit increases the carrier frequency when the power conversion circuit limit temperature arrival time is longer than the rotating electrical machine limit temperature arrival time, and decreases the carrier frequency when the rotating electrical machine limit temperature arrival time is longer than the power conversion circuit limit temperature arrival time. The rotating electrical machine control device according to claim 2.

4. The control unit according to claim 1 switches the method of changing the carrier frequency when at least one of the following conditions is met: when the power conversion circuit temperature is equal to or higher than a predetermined power conversion circuit temperature determination value, and when the rotating electrical machine temperature is equal to or higher than a predetermined rotating electrical machine temperature determination value. The rotating electrical machine control device according to claim 1.

5. The control unit according to claim 1 decreases the carrier frequency when the power conversion circuit temperature is less than a predetermined power conversion circuit temperature determination value and the rotating electrical machine temperature is equal to or higher than a predetermined rotating electrical machine temperature determination value. The rotating electrical machine control device according to claim 1.

6. The control unit increases the carrier frequency when the power conversion circuit temperature is equal to or higher than a predetermined power conversion circuit temperature determination value and the rotating electrical machine temperature is lower than a predetermined rotating electrical machine temperature determination value. The rotating electrical machine control device according to claim 1.

7. The control unit decreases the carrier frequency in response to an increase in the rising rate of the power conversion circuit temperature, and increases the carrier frequency in response to an increase in the rising rate of the rotating electrical machine temperature. The rotating electrical machine control device according to claim 1.

8. The control unit calculates the rising rate of the power conversion circuit temperature from the difference between the power conversion circuit temperature before a predetermined time and the current power conversion circuit temperature, and calculates the rising rate of the rotating electrical machine temperature from the difference between the rotating electrical machine temperature before the time and the current rotating electrical machine temperature. The rotating electrical machine control device according to claim 1.

9. A first temperature detector is disposed on the magnet, winding, or iron core of the rotating electrical machine, a second temperature detector is disposed on the switching element, capacitor, or semiconductor module of the power conversion circuit, and the control unit estimates the rotating electrical machine temperature based on the temperature detected by the first temperature detector, and estimates the power conversion circuit temperature based on the temperature detected by the second temperature detector. The rotating electrical machine control device according to claim 1.

10. A first temperature detector is disposed on the switching element of the power conversion circuit, and the control unit estimates the power conversion circuit temperature based on the temperature detected by the first temperature detector. The rotating electrical machine control device according to claim 9.

11. A first temperature detector is disposed on the capacitor of the power conversion circuit, and the control unit estimates the power conversion circuit temperature based on the temperature detected by the first temperature detector. The rotating electrical machine control device according to claim 9.

12. A first temperature detector is disposed on the semiconductor module of the power conversion circuit, and the control unit estimates the power conversion circuit temperature based on the temperature detected by the first temperature detector. The rotating electrical machine control device according to claim 9.

13. A second temperature detector is disposed on the iron core of the rotating electrical machine, and the control unit estimates the rotating electrical machine temperature based on the temperature detected by the second temperature detector. The rotating electrical machine control device according to claim 9.

14. A second temperature detector is disposed on the magnet of the rotating electrical machine, The rotation electric machine control device according to claim 9, wherein the control unit estimates the rotation electric machine temperature based on the temperature detected by the second temperature detector.

15. A second temperature detector is disposed on the winding of the rotation electric machine, The rotation electric machine control device according to claim 9, wherein the control unit estimates the rotation electric machine temperature based on the temperature detected by the second temperature detector.

16. The control unit, estimates the rotation electric machine temperature based on the temperature detected by the first temperature detector, the phase current value detected by a current detector that detects the current supplied to the winding of the rotation electric machine, and the rotation angle detected by a rotation angle detector provided in the rotation electric machine, The rotation electric machine control device according to claim 9, wherein the control unit estimates the power conversion circuit temperature based on the temperature detected by the second temperature detector, the phase current value detected by the current detector, and the rotation angle detected by the rotation angle detector.

17. The rotation electric machine control device according to any one of claims 1 to 16, wherein the switching element of the power conversion circuit is formed of a wide-gap semiconductor.

18. The rotation electric machine control device according to claim 17, wherein the wide-gap semiconductor of the power conversion circuit contains silicon carbide, gallium nitride diameter material, or diamond.

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