JP2017195741A - Control device and control method for electric power conversion system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device and a control method for an electric power conversion system that can prevent a switching element of the electric power conversion device from reaching a breaking temperature and also suppress permanent pulsation of output electric power from occurring.SOLUTION: A control device is configured to: computes a temperature suppression gain from a high-response temperature suppression gain computed using a high response temperature for each of measured temperatures of one or more switching elements and a low-response temperature suppression gain computed using a low-response temperature for each of the measured temperatures; compute a limit characteristic value by multiplying a rated characteristic value of a load device by a temperature suppression gain; compare a control command for controlling characteristic values of the load device with the computed limit characteristic value; and then output, as a limit control command, a smaller one between the limit characteristic value and control command.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a control device and a control method for a power conversion device that controls a power conversion device that converts the form of power output from a power supply device and outputs the converted power to a load device.

  Common power conversion devices that convert the output form of power include AC / DC converters (Alternate Current / Direct Current) that convert AC power to DC power, inverters that convert DC power to AC power, input voltage, and input Examples include a DC / DC converter that changes the level of current. Such power conversion devices are often configured to include one or more switching elements.

  Examples of the switching element include a diode that allows current to flow only in one direction, a thyristor suitable for handling a large current, and a power transistor that can operate at a high switching frequency. In particular, power transistors are used in a wide range of fields such as automobiles, refrigerators, and air conditioners. The power transistors include IGBTs (Insulated Gate Bipolar Transistors), MOS-FETs (Metal-Oxide-Semiconductor Field-Effect Transistors), and the like, and these elements are used for various purposes.

  In recent years, silicon carbide (SiC) and gallium nitride (GaN) have attracted attention as materials for switching elements. Compared to a conventional switching element using silicon (Si: Silicon), a switching element using SiC or GaN has a low resistance value in the ON state and an effect of reducing loss. In addition, the electron saturation speed is high, switching between the on and off states is quick, and the effect of reducing loss can be obtained.

  Compared to a switching element using Si, a switching element using SiC or GaN can be driven in a higher temperature environment. However, the operating limit temperature of the switching element is fixed, and if the switching element continues to be driven even when this temperature is exceeded, the switching element may be damaged.

  The temperature of the switching element rises due to driving that increases the loss of the switching element, that is, when the power converter outputs a large amount of power, when the switching element is driven at a higher switching frequency, and the like.

  The temperature of the switching element also depends on the environment in which the power conversion device is arranged. The power conversion device includes a cooler that cools a heating element such as a switching element. However, depending on the environment in which the power conversion device is arranged, the temperature of the cooling medium of the cooler increases. Therefore, the temperature of the switching element further increases.

  Here, by stopping the power converter, it is possible to lower the temperature of the switching element and cool the cooling medium. However, for example, a power conversion device for power steering installed in an automobile controls a motor that assists the steering of the automobile. A problem occurs. Therefore, even if the switching element is in a high temperature state, it is necessary to continue driving the power conversion device without damaging the switching element.

  As can be seen from the above, depending on the driving conditions and the arrangement environment of the power conversion device, there is a possibility that the temperature may rise to a temperature at which the switching element is damaged (hereinafter referred to as a failure temperature). Therefore, in order to continue driving the power conversion device while preventing the switching element from reaching the breakage temperature, it is necessary to drive the power conversion device under an appropriate driving condition and arrangement environment. In particular, paying attention to the driving conditions of the power converter, the temperature increase of the switching element can be suppressed by devising and controlling the power converter.

  Here, when the driving condition of the power converter is a driving condition in which the power converter outputs a large amount of power, the temperature of the switching element rises and the temperature may reach the breakage temperature. As an example of the prior art, a technique for managing the temperature of the switching element by forcibly suppressing the output power of the power conversion device has been proposed (see, for example, Patent Document 1).

JP-A-5-284737

  As described above, the temperature of the switching element may reach the failure temperature due to the driving conditions and the arrangement environment of the power converter.

  Since the prior art described in Patent Document 1 is a technique for forcibly suppressing the output power of the power conversion device if the temperature of the switching element is high, it is necessary to accurately measure the temperature of the switching element. However, the temperature sensor that measures the temperature of the switching element is often arranged in the vicinity of the switching element, and as a result, noise due to switching or the like is greatly superimposed on the measured value of the temperature sensor. For this reason, there is a problem that the temperature of the switching element cannot be measured accurately, and the malfunction of the operation for suppressing the output power frequently occurs. In particular, a switching element using SiC or GaN generates a large noise because it can be driven at a high frequency and a high switching speed.

  Further, even if the temperature of the switching element can be accurately measured, there is a problem that a pulsation of temperature, that is, a pulsation of output power occurs due to a control delay due to the open loop control of the temperature. For example, in the prior art described in Patent Document 1, when the measured temperature of the switching element measured by the temperature sensor rises, an operation of reducing the output power of the power converter is performed. At this time, since the switching element has a low heat capacity, the measured temperature also decreases immediately, but a control delay due to open loop control occurs, and the output power and thus the measured temperature are decreased more than necessary. Even when the operation of increasing the output power of the power converter is performed, the measured temperature is similarly increased more than necessary. When such an operation occurs continuously, pulsation occurs in the output power of the power converter.

  Here, as a technique for removing noise, there is a technique for passing the measured temperature of the switching element measured by the temperature sensor through a filter such as a low-pass filter (LPF). However, the measured temperature after filtering obtained by passing the measured temperature of the switching element through the filter is delayed with respect to the measured temperature before filtering. The delay time can be manipulated by the cutoff frequency of the filter.

  Configuration that manages the measured temperature by forcibly suppressing the output power of the power converter using the measured temperature after filtering that is obtained by passing the measured temperature of the switching element through a filter with a low cutoff frequency In this case, the pulsation of the measured temperature due to noise or control delay is removed, and the pulsation of the output power does not occur. However, the timing for suppressing the output power is greatly delayed, and as a result, there is a high possibility that the measured temperature of the switching element exceeds the breakage temperature.

  On the other hand, in the above configuration, when a filter with a high cut-off frequency is used in order to shorten the delay time, the timing for suppressing the output power of the power converter becomes earlier, and as a result, the measured temperature of the switching element Is less likely to exceed the failure temperature. However, the pulsation of the measured temperature due to the control delay is not removed, and the pulsation of the measured temperature and the pulsation of the output power are generated.

  As can be seen from the above, in the prior art described in Patent Document 1, since the noise caused by switching is greatly superimposed on the measured temperature of the switching element, the temperature of the switching element cannot be accurately measured. As a result, there is a problem that malfunctions of operations that suppress output power frequently occur. Even if a filter is used to remove noise superimposed on the measured temperature of the switching element, the measured temperature of the switching element may exceed the breakage temperature or be controlled by the delay of the timing to suppress the output power. There is a problem that the output power pulsates due to the delay.

  The present invention has been made to solve the above-described problems, and suppresses the occurrence of permanent pulsation of output power while preventing the temperature of the switching element from reaching the breakage temperature in the power conversion device. It is an object of the present invention to obtain a control device and a control method for a power conversion device that can be used.

  The control device of the power conversion device according to the present invention has one or more switching elements, and each switching device is controlled to be switched on and off, thereby converting the form of power output from the power supply device and converting A control device that controls a power conversion device that outputs the subsequent power to a load device, and determines an operation feasibility temperature based on each measured temperature measured by a switching element temperature sensor that measures the temperature of each switching element, The temperature suppression unit includes a temperature suppression unit that starts a temperature suppression operation when the operation availability temperature is equal to or higher than the first set threshold, and the temperature suppression unit sets each measurement temperature as the high response temperature as it is, thereby setting the high response temperature for each measurement temperature. And a temperature filter unit that generates a low response temperature for each measurement temperature by passing each measurement temperature through a low response filter. Gain calculation for determining the high response temperature for gain calculation based on the high response temperature for each measured temperature and determining the low response temperature for gain calculation based on the low response temperature for each measurement temperature generated by the temperature filter unit And a gain calculation temperature determination unit that calculates a high response temperature suppression gain such that the higher the response high response temperature determined by the gain calculation temperature determination unit is, the smaller the high response temperature suppression gain is. The low response temperature suppression gain is calculated so that the lower the response temperature suppression gain becomes, the smaller the gain response low response temperature determined by (1) is, and the temperature suppression gain is calculated from the calculated high response temperature suppression gain and low response temperature suppression gain. The temperature suppression gain calculation unit to be calculated and the temperature suppression gain calculated by the temperature suppression gain calculation unit for the rated characteristic value of the load device By multiplying, the limit characteristic value is calculated and the control command for controlling the characteristic value of the load device is compared with the calculated limit characteristic value. A limit control command calculation unit that outputs as a limit control command, and the control device controls each switching element of the power converter to be turned on and off according to the limit control command output from the limit control command calculation unit It is.

  Also, the control method of the power conversion device according to the present invention has one or more switching elements, and each switching element is controlled to be switched on and off, thereby converting the form of power output from the power supply device. A method for controlling a power conversion device that outputs converted power to a load device, and determines an operational temperature based on each measured temperature measured by a switching element temperature sensor that measures the temperature of each switching element. And a temperature suppression step for starting a temperature suppression operation when the operation feasibility temperature is equal to or higher than the first set threshold value, and the temperature suppression step uses the measured temperature as the high response temperature as it is to measure the high response temperature. And generating a low response temperature for each measurement temperature by passing each measurement temperature through a low response filter, and the generated measurement temperature. Determining a high response temperature for gain calculation based on the high response temperature for each measurement, determining a low response temperature for gain calculation based on the low response temperature for each generated measurement temperature, and determining the determined gain calculation high The high response temperature suppression gain is calculated so that the high response temperature suppression gain decreases as the response temperature increases, and the low response temperature suppression gain decreases as the determined low response temperature for gain calculation increases. By calculating the gain, calculating the temperature suppression gain from the calculated high response temperature suppression gain and low response temperature suppression gain, and multiplying the rated characteristic value of the load device by the calculated temperature suppression gain, By calculating the limit characteristic value and comparing the control command for controlling the characteristic value of the load device with the calculated limit characteristic value, the limit characteristic value and the control Write small and has a step of outputting as a limit control instruction, the one in which further comprising a control step of switching control on and off the switching elements of the power converter in accordance with a limit control instruction to be output.

  ADVANTAGE OF THE INVENTION According to this invention, the control apparatus and control method of the power converter device which can suppress that a permanent pulsation generate | occur | produces in output power, suppressing that a switching element is damaged by high temperature in a power converter device. Can be obtained.

It is a block diagram which shows the load drive system provided with the control apparatus of the power converter device in Embodiment 1 of this invention. It is a block diagram which shows the structure of the control apparatus of the power converter device in Embodiment 1 of this invention. It is a block diagram which shows the structure of the temperature suppression part in Embodiment 1 of this invention. It is explanatory drawing which shows the association for high response and the association for low response in Embodiment 1 of this invention. It is explanatory drawing for demonstrating operation | movement of the temperature suppression part in Embodiment 1 of this invention. It is explanatory drawing for demonstrating operation | movement of the temperature suppression part in Embodiment 2 of this invention.

  Hereinafter, a control device and a control method of a power converter according to the present invention will be described with reference to the drawings according to a preferred embodiment. In the description of the drawings, the same portions or corresponding portions are denoted by the same reference numerals, and redundant description is omitted. Moreover, in each embodiment, the case where this invention is applied with respect to the three-phase inverter which has a U phase, a V phase, and a W phase which drives an alternating current motor is illustrated.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram illustrating a load drive system including a control device 8 for a power conversion device according to Embodiment 1 of the present invention. 1 includes an electric motor 1, a power supply device 2, a power conversion device 3, a rotation angle sensor 4, a motor temperature sensor 5, a switching element temperature sensor 6, a command generator 7, and a power conversion. And a control device 8 of the device (hereinafter abbreviated as control device 8).

  In the first embodiment, the case where the power conversion device 3 is an inverter device is illustrated. However, the power conversion device 3 is not limited to the inverter device, but is a power conversion device including one or more switching elements, for example, AC / AC. It may be a DC converter device, a DC / DC converter device, or the like. Moreover, although the case where the power supply device 2 outputs DC power is exemplified, depending on the type of the power conversion device 3, AC power may be output. Furthermore, although the case where the load device to which power is supplied from the power conversion device 3 is the electric motor 1 is illustrated, the load device is not limited to the electric motor but may be other load devices other than the electric motor.

  An electric motor 1 that is an example of a load device is controlled according to a PWM method. The electric motor 1 is, for example, an in-vehicle electric motor. In addition, the vehicle-mounted electric motor here specifically refers to a driving electric motor for driving a vehicle, an electric fan, an oil pump, a water pump, an electric power steering device for assisting the steering operation of the vehicle, and the like. It is used for. Further, the electric motor 1 is not limited to an in-vehicle electric motor, and may be an electric motor other than the in-vehicle electric motor.

  Hereinafter, description will be made assuming that the electric motor 1 is a three-phase brushless motor having a rotor and a stator. The rotor is a disk-shaped member, and a permanent magnet is affixed to the surface thereof and has a magnetic pole. The stator accommodates the rotor therein so as to be relatively rotatable. The stator has a protruding portion that protrudes in the radially inward direction for each preset angle, and a U-phase coil 11, a V-phase coil 12, and a W-phase coil 13 are wound around the protruding portion.

  The power supply device 2 is a drive source of the electric motor 1 and outputs DC power to the power conversion device 3. As a specific configuration example of the power supply device 2, the power supply device 2 includes a battery 21 that is an example of a DC power supply that outputs DC power, a smoothing capacitor 22, and a choke coil 23.

  The smoothing capacitor 22 and the choke coil 23 are arranged between the battery 21 and a switching circuit 31 to be described later, and constitute a power filter. With this configuration, noise transmitted from the other device sharing the battery 21 to the switching circuit 31 side can be reduced, and noise transmitted from the switching circuit 31 side to the other device sharing the battery 21 can be reduced. it can. The smoothing capacitor 22 accumulates charges to assist power supply to the switching elements 311 to 316, and further suppress noise components such as surge current. Further, the voltage Vbat of the battery 21 and the voltage Vcon of the smoothing capacitor 22 are acquired by the control device 8.

  The power conversion device 3 has one or more switching elements, and each switching element is controlled to be switched on and off, thereby converting the form of power output from the power supply device 2, and converting the converted power to Output to the load device. Specifically, the power conversion device 3 converts the DC power supplied from the power supply device 2 into AC power, and outputs the converted AC power to the electric motor 1. As a specific configuration example of the power conversion device 3, the power conversion device 3 includes a switching circuit 31, a current detection circuit 32, an amplification circuit 33, and a drive circuit 34.

  The switching circuit 31 is connected to a plurality of half bridge circuits each having a switching element in each of the upper arm and the lower arm, and the switching element is controlled to be turned on and off in accordance with the PWM signal. The converted DC power is converted into AC power, and the converted AC power is output to the electric motor 1.

  In FIG. 1, the case where the switching circuit 31 is comprised by three half-bridge circuits is illustrated. Switching circuit 31 includes switching elements 311 to 316. The switching circuit 31 is a three-phase inverter, and six switching elements 311 to 316 are bridge-connected to switch energization to each of the U-phase coil 11, the V-phase coil 12, and the W-phase coil 13. As the switching elements 311 to 316, a MOSFET that is a kind of field effect transistor may be used, and another transistor different from the MOSFET, an IGBT, or the like may be used. Hereinafter, the switching elements 311 to 316 are referred to as SW311 to 316.

  The drains of the three SWs 311 to 313 are connected to the positive electrode side of the battery 21. The sources of SW311 to 313 are connected to the drains of SW314 to 316, respectively. The sources of the SWs 314 to 316 are connected to the negative electrode side of the battery 21.

  A connection point connecting the pair of SW 311 and SW 314 is connected to one end of the U-phase coil 11. A connection point connecting the pair of SW 312 and SW 315 is connected to one end of the V-phase coil 12. Further, a connection point connecting the pair of SW 313 and SW 316 is connected to one end of the W-phase coil 13.

  Hereinafter, SW 311 to 313 that are switching elements arranged on the high potential side are referred to as “upper SW”, and SW 314 to 316 that are switching elements arranged on the low potential side are referred to as “lower SW”. To do. In the first embodiment, the potential on the low potential side is set to 0 V for easy understanding.

  The current detection circuit 32 includes a U-phase current detection unit 321, a V-phase current detection unit 322, and a W-phase current detection unit 323. The U-phase current detection unit 321, the V-phase current detection unit 322, and the W-phase current detection unit 323 are configured using, for example, a shunt resistor. Hereinafter, the U-phase current detection unit 321, the V-phase current detection unit 322, and the W-phase current detection unit 323 are appropriately referred to as current detection units 321 to 323, respectively.

  The U-phase current detection unit 321 detects a U-phase current Iu as a current flowing through the U-phase coil 11. V-phase current detection unit 322 detects V-phase current Iv as a current flowing through V-phase coil 12. The W-phase current detection unit 323 detects a W-phase current Iw as a current flowing through the W-phase coil 13. Further, the detection values detected by the current detection units 321 to 323 are input to the control device 8 via the amplifier circuit 33. The amplifier circuit 33 is for taking in the detection values detected by the current detection units 321 to 323 as appropriate values that can be processed in the control device 8.

  The drive circuit 34 has a function of switching on and off each of the SWs 314 to 316 based on the PWM signal input from the control device 8.

  The rotation angle sensor 4 is attached to the electric motor 1 and detects position information indicating the rotor position of the electric motor 1, specifically, the rotation angle θm of the rotor. The rotation angle sensor 4 is configured using, for example, a resolver. The rotation angle sensor 4 is configured to convert the detected rotation angle θm into an electrical angle θe based on the number of pole pairs of the permanent magnet of the electric motor 1. The rotation angle θm and the electrical angle θe are acquired by the control device 8.

  The electric motor temperature sensor 5 measures the temperature of the electric motor 1. The electric motor temperature sensor 5 is configured by a temperature detector such as a thermistor attached to the U-phase coil 11, the V-phase coil 12, and the W-phase coil 13, for example. The temperature of the electric motor 1 is acquired by the control device 8.

  The switching element temperature sensor 6 measures each temperature Tj of SW311 to SW316. Hereinafter, the temperature Tj measured by the switching element temperature sensor 6 is referred to as a measured temperature Tj. The switching element temperature sensor 6 is configured by, for example, a temperature detection circuit attached to each of the SW 311 to SW 316. The measured temperatures Tj of SW311 to SW316 are acquired by the control device 8.

  The command generator 7 is a device that generates a control command for controlling the electric motor 1 and outputs the control command to the control device 8. Specifically, for example, when the electric motor 1 is used as a drive source of a vehicle such as an electric vehicle, the command generator 7 issues a control command corresponding to the depression angle of the accelerator pedal operated by the driver of the vehicle. Convert. The control command generated by the command generator 7 is periodically transmitted to the control device 8 by communication.

  In addition, as a control command for controlling the characteristic value of the electric motor 1, for example, a torque command for controlling the torque of the electric motor 1, a current command for controlling the electric current of the electric motor 1, and a voltage of the electric motor 1 are controlled. For example, a voltage command for controlling the rotation speed of the electric motor 1, and the like. In the first embodiment, a case where a torque command Trq * is adopted as a control command is exemplified.

  The control device 8 controls the entire load drive system, and is realized by, for example, a microcomputer configured to execute a program stored in a memory.

  Next, the configuration of the control device 8 will be further described with reference to FIG. FIG. 2 is a block diagram showing the configuration of the control device 8 according to Embodiment 1 of the present invention.

  As shown in FIG. 2, the control device 8 includes a temperature suppression unit 81, a rotation speed calculation unit 82, a torque / current command conversion unit 83, a three-phase two-phase conversion unit 84, a voltage command generation unit 85, A two-phase / three-phase converter 86, a duty converter 87, and a PWM signal generator 88 are included.

  The temperature suppression unit 81 calculates a limit torque command Trq_EN * from the torque command Trq * acquired from the command generator 7 and the measured temperatures Tj of SW311 to SW316 acquired from the switching element temperature sensor 6, and the limit torque is calculated. Command Trq_EN * is output to torque / current command conversion unit 83.

  A more detailed description of the temperature suppression unit 81 will be described later. Moreover, in this Embodiment 1, it becomes the form which suppresses the output electric power of the power converter device 3 by suppressing the torque instruction Trq * as a control instruction. However, it is good also as a form which suppresses the output electric power of the power converter device 3 by suppressing not only torque instruction Trq * but the current command, voltage command, rotation speed command, etc. as a control command.

  The rotation speed calculation unit 82 integrates the rotation angle θm acquired from the rotation angle sensor 4 and converts it to the rotation speed N of the electric motor 1. The rotation speed calculation unit 82 outputs the rotation speed N to the torque / current command conversion unit 83.

  The torque / current command conversion unit 83 calculates the d-axis current command Id * and the q-axis current from the rotation speed N of the electric motor 1 acquired from the rotation speed calculation unit 82 and the limit torque command Trq_EN * acquired from the temperature suppression unit 81. Command Iq * is calculated. Specifically, for example, the torque / current command conversion unit 83 uses the torque / current command conversion table with the rotation speed N of the electric motor 1 and the limit torque command Trq_EN * as axes, and converts these values into the d-axis current. It is configured to convert into a command Id * and a q-axis current command Iq *. Further, the torque / current command conversion unit 83 may be configured to calculate the d-axis current command Id * and the q-axis current command Iq * without using the torque / current command conversion table.

  The three-phase to two-phase converter 84 includes the U-phase current Iu, the V-phase current Iv, and the W-phase current Iw acquired from the current detectors 321 to 323, that is, the three-phase currents Iu, Iv, and Iw The d-axis current detection value Id and the q-axis current detection value Iq are calculated from the acquired electrical angle θe.

  The voltage command generation unit 85 performs a current feedback calculation from the d-axis current command Id * and the q-axis current command Iq * and the d-axis current detection value Id and the q-axis current detection value Iq, so that the d-axis voltage command Vd * and q-axis voltage command Vq * are calculated. Specifically, for example, the voltage command generation unit 85 includes the current deviation ΔId that is a deviation between the d-axis current command Id * and the d-axis current detection value Id, the q-axis current command Iq *, and the q-axis current detection value Iq. The d-axis voltage command Vd * and the q-axis voltage command Vq * are calculated so that the current deviation ΔIq, which is a deviation from the above, converges to 0.

  The two-phase / three-phase converter 86 uses the three-phase voltage command Vu from the d-axis voltage command Vd * and the q-axis voltage command Vq * acquired from the voltage command generator 85 and the electrical angle θe acquired from the rotation angle sensor 4. *, Vv *, Vw * are calculated. The three-phase voltage commands Vu *, Vv *, Vw * are preferably set to be equal to or lower than the DC power supply voltage input to the switching circuit 31, that is, the voltage Vcon of the smoothing capacitor 22.

  The duty converter 87 calculates the duty command Du, Dv, Dw of each phase from the three-phase voltage commands Vu *, Vv *, Vw * acquired from the two-phase three-phase converter 86 and the voltage Vcon of the smoothing capacitor 22. Generate.

  The PWM signal generation unit 88 generates a PWM signal for switching on and off each of the SWs 311 to 316 from the duty commands Du, Dv, and Dw of each phase acquired from the duty conversion unit 87. Specifically, for example, the PWM signal generation unit 88 is configured to generate a PWM signal by comparing each phase duty command Du, Dv, Dw with a carrier wave. The PWM signal generation unit 88 is configured to generate a PWM signal by adopting, for example, a triangular wave comparison method using a triangular wave of an isosceles triangle shape having the same ascending speed and falling speed, a sawtooth wave comparison method, and the like. The

  In FIG. 2, as the PWM signal generated by the PWM signal generator 88, the U-phase upper SW signal is UH_SW, the U-phase lower SW signal is UL_SW, and the V-phase upper SW signal is VH_SW, V The lower SW signal for the phase is denoted as VL_SW, the upper SW signal for the W phase is denoted as WH_SW, and the lower SW signal for the W phase is denoted as WL_SW.

  As described above, the control device 8 is configured to control the switching elements of the power conversion device 3 to be turned on and off in accordance with the limit torque command Trq_EN * output from the temperature suppression unit 81.

  Next, details of the temperature suppression unit 81, which is a characteristic part of the present invention, will be described with reference to FIG. FIG. 3 is a block diagram showing the configuration of the temperature suppression unit 81 according to Embodiment 1 of the present invention.

  As shown in FIG. 3, the temperature suppression unit 81 includes an operation availability determination unit 811, a temperature filter unit 812, a gain calculation temperature determination unit 813, a temperature suppression gain calculation unit 814, and a limit control command calculation unit 815. It consists of

  The operation enable / disable determining unit 811 determines the operation enable / disable temperature based on the measured temperatures Tj of the SW 311 to SW 316 acquired from the switching element temperature sensor 6. Specifically, the operation availability determination unit 811 determines the maximum measurement temperature Tj among the measurement temperatures Tj as the operation availability temperature. In the first embodiment, not only the above-described configuration but also the average value or median value of the measured temperatures Tj may be set as the operable temperature.

  The operation enable / disable determining unit 811 compares the determined operation enable / disable temperature with the first set threshold value a, and determines that the operation enable / disable temperature has reached the first set threshold value a. The suppression operation, that is, each operation of the temperature filter unit 812, the gain calculation temperature determination unit 813, the temperature suppression gain calculation unit 814, and the limit control command calculation unit 815 is started. The first setting threshold value a will be described later.

  On the other hand, when the operation enable / disable determining unit 811 determines that the operation enable / disable temperature does not reach the first set threshold value a, that is, the operation enable / disable temperature is less than the first set threshold value a, the temperature suppressing unit 81. Does not start the temperature suppression operation. In this case, the temperature suppression operation by the temperature suppression unit 81 is not performed, and the torque command Trq * input from the command generator 7 to the temperature suppression unit 81 is input to the torque / current command conversion unit 83 as the limit torque command Trq_EN * as it is. The

  As described above, the temperature suppression unit 81 determines the operating temperature based on each measured temperature measured by the switching element temperature sensor 6 that measures the temperature of each SW 311 to 316, and the operating temperature is the first setting. The temperature suppression operation is configured to start when the threshold value a is equal to or greater than the threshold value a.

  When the temperature suppression operation starts, the temperature filter unit 812 generates a high response temperature TjH and a low response temperature TjL for each measurement temperature Tj using each measurement temperature Tj acquired from the switching element temperature sensor 6. The high response temperature TjH corresponds to a temperature having a shorter delay time than the measurement temperature Tj, and the low response temperature TjL corresponds to a temperature having a longer delay time than the measurement temperature Tj.

  Specifically, the temperature filter unit 812 generates a high response temperature TjH for each measurement temperature Tj by passing each measurement temperature Tj acquired from the switching element temperature sensor 6 through an LPF as a high response filter. Further, the temperature filter unit 812 generates a low response temperature TjL for each measurement temperature Tj by passing each measurement temperature Tj acquired from the switching element temperature sensor 6 through an LPF as a low response filter. The cut-off frequency of the high response filter is set higher than the cut frequency of the low response filter.

  The temperature filter unit 812 uses the high response temperature TjH for each measurement temperature Tj by using each measurement temperature Tj acquired from the switching element temperature sensor 6 as the high response temperature TjH without using the high response filter. It may be configured to generate. In the first embodiment, the case where two types of temperatures, ie, the high response temperature TjH and the low response temperature TjL are generated is illustrated. However, the present invention is not limited to this. For example, the cutoff frequency is medium. Various temperatures such as response temperature may be generated. Furthermore, although the case where LPF is used as the high response filter and the low response filter is illustrated in the first embodiment, the present invention is not limited to this, and other filters capable of removing noise may be used.

  The gain calculation temperature determination unit 813 determines the gain calculation high response temperature based on the high response temperature TjH for each measurement temperature Tj acquired from the temperature filter unit 812. The gain calculation temperature determination unit 813 determines the gain calculation low response temperature based on the low response temperature TjL for each measurement temperature Tj acquired from the temperature filter unit 812.

  Specifically, the gain calculation temperature determination unit 813 determines the maximum response high temperature TjH from the high response temperatures TjH for each measured temperature Tj as the high response maximum temperature TjHM as the gain calculation high response temperature. To do. Further, the gain calculation temperature determination unit 813 determines the maximum low response temperature TjL from the low response temperatures TjL for each measured temperature Tj as the low response maximum temperature TjLM as the gain calculation low response temperature.

  As described above, the gain calculation temperature determination unit 813 selects one high response temperature TjH from the high response temperatures TjH for each measurement temperature Tj and low response from the low response temperatures TjL for each measurement temperature Tj. One temperature TjL is selected. Therefore, calculation using all of the high response temperature TjH and the low response temperature TjL becomes unnecessary, and as a result, the calculation time can be shortened.

  In the first embodiment, the average value or median value of each high response temperature TjH is not limited to the above-described configuration, and the gain calculation high response temperature may be used. The response temperature TjH may be selected as the high response temperature for gain calculation. Similarly, the present invention is not limited to the above configuration, and the average value or median value of the low response temperatures TjL may be used as the low response temperature for gain calculation, or the processing time is increased but one or more low response temperatures TjL are gain calculated. It may be selected as a low response temperature.

  The temperature suppression gain calculation unit 814 calculates the high response temperature suppression gain αH so that the high response temperature suppression gain αH decreases as the high response maximum temperature TjHM determined by the gain calculation temperature determination unit 813 increases. Further, the temperature suppression gain calculation unit 814 calculates the low response temperature suppression gain αL so that the low response temperature suppression gain αL decreases as the low response maximum temperature TjLM determined by the gain calculation temperature determination unit 813 increases.

  Specifically, the temperature suppression gain calculation unit 814 corresponds to the high response maximum temperature TjHM acquired from the gain calculation temperature determination unit 813 from the high response association between the high response maximum temperature TjHM and the high response temperature suppression gain αH. The high response temperature suppression gain αH is calculated. Further, the temperature suppression gain calculation unit 814 has a low response corresponding to the low response maximum temperature TjLM acquired from the gain calculation temperature determination unit 813 based on the low response association between the low response maximum temperature TjLM and the low response temperature suppression gain αL. The temperature suppression gain αL is calculated.

  Here, the association for high response and the association for low response will be described with reference to FIG. FIG. 4 is an explanatory diagram showing association for high response and association for low response according to Embodiment 1 of the present invention.

  As shown in FIG. 4, the high response association is based on the second set threshold value b (the maximum response maximum temperature TjHM is higher than the first set threshold value a from the first set threshold value a (hereinafter abbreviated as the threshold value a)). Hereinafter, the high response temperature suppression gain αH is set so as to change from 1 to 0 as the threshold value changes. The low response association is set so that the low response temperature suppression gain αL changes from 1 to 0 as the low response maximum temperature TjLM changes from the threshold value a to the threshold value b. The threshold value a and the threshold value b may be set in advance, the threshold value a is a temperature at which the temperature suppression operation by the temperature suppression unit 81 is started, and the threshold value b is a temperature lower than the breakage temperature of the SWs 311 to 316. .

  In the first embodiment, in the high response association and the low response association, the high response temperature suppression gain αH and the low response temperature suppression gain αL are linearly decreased from the threshold value a to the threshold value b. However, it may be reduced by non-linearity or discontinuity.

  Moreover, although the values of the high response temperature suppression gain αH and the low response temperature suppression gain αL calculated by the temperature suppression gain calculation unit 814 exemplify, they may be different.

  That is, the change from 1 to 0 of the high response temperature suppression gain αH in the association for high response matches the change from 1 to 0 of the low response temperature suppression gain αL in the association for low response. Not only this but these changes may differ. If these changes are different, the high response temperature suppression gain αH and the low response temperature suppression gain αL calculated by the temperature suppression gain calculation unit 814 can be made different.

  Returning to the description of FIG. 3, the temperature suppression gain calculator 814 calculates the temperature suppression gain α from the calculated high response temperature suppression gain αH and low response temperature suppression gain αL.

  Specifically, when the temperature suppression operation is started, the temperature suppression gain calculation unit 814 outputs the temperature suppression gain α as the high response temperature suppression gain αH to the limit control command calculation unit 815, and after the start of the temperature suppression operation At this switching timing, the temperature suppression gain α is switched from the high response temperature suppression gain αH to the low response temperature suppression gain αL and output to the limit control command calculation unit 815.

  Limit control command calculation unit 815 calculates a value obtained by multiplying rated torque of motor 1 by temperature suppression gain α acquired from temperature suppression gain calculation unit 814 as limit torque Trq_EN as a limit characteristic value. Further, the limit control command calculation unit 815 compares the calculated limit torque Trq_EN with the torque command Trq * acquired from the command generator 7, thereby obtaining the smaller value of the limit torque Trq_EN and the torque command Trq *. Output as limit torque command Trq_EN * as limit control command. The rated torque of the electric motor 1 depends on the rotational speed N, the voltage Vcon of the smoothing capacitor 22, and the like, but in the first embodiment, the rated torque is set in advance as a constant value.

  In addition, in this Embodiment 1, although the case where rated torque is used as a rated characteristic value is illustrated, not only this but a rated voltage, a rated current, and a rated rotation speed are used as a rated characteristic value, for example. Good. The rated characteristic value may be determined according to what command is used as the control command.

  Next, the operation of the temperature suppression unit 81 will be further described with reference to FIG. FIG. 5 is an explanatory diagram for explaining the operation of the temperature suppression unit 81 according to Embodiment 1 of the present invention.

  In FIG. 5, (A) shows, as a comparative example, a high response temperature suppression gain αH, a limit torque command Trq_EN *, when the temperature suppression gain α is output to the limit control command calculation unit 815 as a high response temperature suppression gain αH, The time change of measurement temperature Tj is shown. (B) shows, as a comparative example, the low response temperature suppression gain αL, the limit torque command Trq_EN *, and the measured temperature Tj when the temperature suppression gain α is output to the limit control command calculation unit 815 as the low response temperature suppression gain αL. The time change is shown.

  (C), as an example, outputs the temperature suppression gain α as the high response temperature suppression gain αH to the limit control command calculation unit 815 and suppresses the temperature at a preset switching time tc (hereinafter abbreviated as time tc). The time change of the temperature suppression gain α, the limit torque command Trq_EN *, and the measured temperature Tj when the gain α is switched from the high response temperature suppression gain αH to the low response temperature suppression gain αL and output to the limit control command calculation unit 815 is shown. ing.

  Here, in the temperature filter unit 812, the initial value of the high response temperature TjH generated for each measured temperature Tj and the initial value of the low response temperature TjL generated for each measured temperature Tj must be set appropriately. This is because the values of the high response maximum temperature TjHM and the low response maximum temperature TjLM may not match the threshold value a at the start of the temperature suppression operation due to the delay time of the LPF. That is, at the start of the temperature suppression operation, it is preferable that the high response maximum temperature TjHM reaches the threshold value a and the low response maximum temperature TjLM reaches the threshold value a.

  Therefore, in the first embodiment, in the temperature filter unit 812, the initial value of the high response temperature TjH generated for each measured temperature Tj and the initial value of the low response temperature TjL generated for each measured temperature Tj are threshold values. It is set to be a. By doing in this way, the high response maximum temperature TjHM reaches the threshold value a, and at the same time, the low response maximum temperature TjLM can reach the threshold value a.

  The high response temperature suppression gain αH shown in FIG. 5A quickly decreases because the delay due to LPF is shorter than the low response temperature suppression gain αL shown in FIG. 5B. This is because the high response maximum temperature TjHM quickly decreases. Further, the limit torque command Trq_EN * and the measured temperature Tj are quickly set in accordance with the high response temperature suppression gain αH.

  However, since the maximum response temperature TjHM has a short delay time with respect to the measured temperature Tj, permanent torque pulsation as described above occurs.

  The low response temperature suppression gain αL shown in FIG. 5B is gradually decreasing because the delay due to the LPF is long. This is because the low response maximum temperature TjLM gradually decreases. Further, the limit torque command Trq_EN * and the measured temperature Tj are gently set according to the low response temperature suppression gain αL. Further, as compared with FIG. 5A, no permanent torque pulsation occurs.

  However, as compared with FIG. 5A, the limit torque Trq_EN is increased immediately after the start of the temperature suppression operation. This is because the low response temperature suppression gain αL has gradually decreased. That is, the limit torque Trq_EN increases as the cutoff frequency of the low response filter of the temperature filter unit 812 decreases.

  The temperature suppression gain α shown in FIG. 5C becomes the high response temperature suppression gain αH when the temperature suppression operation is started, and decreases from the high response temperature suppression gain αH after the elapse of time tc from the start of the temperature suppression operation. The response temperature suppression gain αL is switched.

  Therefore, as in FIG. 5A, the measured temperature Tj does not increase immediately after the start of the temperature suppression operation, and further, the time is changed from the high response temperature suppression gain αH to the low response temperature suppression gain αL after the elapse of time tc. Although some torque pulsation occurs before the elapse of tc, no torque pulsation occurs after the elapse of time tc, as in FIG. 5B.

  As described above, in the first embodiment, by appropriately switching from the high response temperature suppression gain αH to the low response temperature suppression gain αL, permanent torque pulsation is not generated, and the switching element is not reached up to the failure temperature. It is configured so that the temperature is saturated.

  In the first embodiment, the switching timing for switching the temperature suppression gain α from the high response temperature suppression gain αH to the low response temperature suppression gain αL is set to the timing when the time tc has elapsed since the temperature suppression operation was started. Although the case is illustrated, the present invention is not limited to this, and any timing may be set. For example, the switching timing may be set to a timing at which the low response maximum temperature TjLM is stabilized from the transient state to the steady state.

  Here, in order to stop the temperature suppression operation, the torque command Trq * needs to be smaller than the limit torque Trq_EN. However, in the above configuration, when it is determined that the temperature suppression operation is stopped based on the measured temperature Tj, there is a possibility that the operation start and the operation stop are repeated due to temperature pulsation. Therefore, the temperature suppression unit 81 is configured to stop the temperature suppression operation when the low response maximum temperature TjLM as the gain calculation low response temperature becomes equal to or lower than the threshold value a during the temperature suppression operation. preferable.

  As described above, according to the first embodiment, the high response temperature suppression gain calculated using the high response temperature for each measurement temperature of one or more switching elements and the low response temperature calculated using the low response temperature for each measurement temperature. The temperature suppression gain is calculated from the response temperature suppression gain. Specifically, when the temperature suppression operation is started, the temperature suppression gain is set to the high response temperature suppression gain, and the temperature suppression gain is changed from the high response temperature suppression gain to the low response temperature suppression gain at the switching timing after the start of the temperature suppression operation. It is configured to switch to.

  Moreover, the limit characteristic value is calculated by multiplying the rated characteristic value of the load device by the temperature suppression gain, and the control command for controlling the characteristic value of the load device is compared with the calculated limit characteristic value. Thus, the smaller of the limit characteristic value and the control command is output as the limit control command.

  By configuring as described above, in the power conversion device, it is possible to suppress the occurrence of permanent pulsation of the output power while preventing the temperature of the switching element from reaching the breakage temperature without increasing the cost. . Moreover, since the temperature of the switching element can be prevented from reaching the breakage temperature while the control for suppressing the output power of the power conversion device is being executed, the power conversion device can be continuously driven as a result. .

  In addition, although each switching element of a power converter device may be comprised using what kind of semiconductor element, it is preferable that each switching element is comprised using the wide band gap semiconductor. Examples of the material for the wide band gap semiconductor include SiC and GaN.

  A power conversion device including a switching element configured using a wide band gap semiconductor has higher heat resistance and low loss than a power conversion device including a switching element configured using a conventional Si semiconductor. The feature is that high frequency driving is possible. Therefore, by configuring the switching element using a wide band gap semiconductor, heat generation can be further suppressed with low loss, and since it has high heat resistance, it is possible to realize a power conversion device that is less likely to be damaged. it can.

Embodiment 2. FIG.
In the second embodiment of the present invention, a temperature suppression unit 81 having a temperature suppression gain calculation unit 814 that calculates a temperature suppression gain α by a calculation method different from that of the first embodiment will be described. In the second embodiment, description of points that are the same as those of the first embodiment will be omitted, and points different from the first embodiment will be mainly described.

  Here, in the configuration of the temperature suppression gain calculation unit 814 in the first embodiment, that is, the configuration in which the temperature suppression gain α is switched from the high response temperature suppression gain αH to the low response temperature suppression gain αL at the switching timing, partly Torque pulsation may occur or the temperature suppression gain α may become discontinuous. Therefore, in the present second embodiment, the configuration of the temperature suppression gain calculation unit 814 is changed with respect to the first embodiment to improve.

  The temperature suppression gain calculation unit 814 calculates the temperature suppression gain α according to the following equation (1) using the high response temperature suppression gain αH, the low response temperature suppression gain αL, and the constant h. However, h is a constant set in advance and satisfies 0 <h <1.

    α = αH × h + αL × (1−h) (1)

  Unlike the configuration in which the temperature suppression gain α is switched from the high response temperature suppression gain αH to the low response temperature suppression gain αL by configuring the temperature suppression gain calculation unit 814 as described above, the temperature suppression gain α does not become discontinuous. .

Moreover, you may comprise the temperature suppression gain calculating part 814 as follows. That is, the temperature suppression gain calculation unit 814 uses the high response temperature suppression gain αH, the low response temperature suppression gain αL, and the variable h _(t) as the weighting variable according to the following equation (2). Calculate the gain α.

α = αH × h _(t) + αL × (1−h _(t) ) (2)

However, t is the elapsed time from the start of the temperature suppression operation. The variable h _(t) is a time variable that changes with the elapsed time t and is continuous. Furthermore, the variable h _(t) is a preset variable and satisfies 0 <h _(t) <1.

  Here, when the temperature suppression gain calculation unit 814 is configured to calculate the temperature suppression gain α according to the equation (2), the time change of the temperature suppression gain α, the limit torque command Trq_EN *, and the measured temperature Tj is shown in FIG. This will be described with reference to FIG. FIG. 6 is an explanatory diagram for explaining the operation of the temperature suppression unit 81 according to Embodiment 2 of the present invention.

As shown in FIG. 6, in the configuration of the temperature suppression gain calculation unit 814 described above, if the temperature suppression gain α does not become discontinuous and the variable h _(t) can be set appropriately, torque pulsation is generated. It does not occur.

In addition, by making the high response temperature suppression gain αH and the low response temperature suppression gain αL calculated by the gain calculation temperature determination unit 813 different from each other, the above effect can be obtained without using the variable h _(t). Similar results can be obtained.

  As described above, according to the second embodiment, the method of calculating the temperature suppression gain is changed from the configuration of the first embodiment. In particular, by configuring so that the temperature suppression gain is optimally calculated using a time variable, torque pulsation does not occur and the temperature suppression gain does not become discontinuous.

  DESCRIPTION OF SYMBOLS 1 Electric motor, 2 Power supply device, 3 Power converter, 4 Rotation angle sensor, 5 Motor temperature sensor, 6 Switching element temperature sensor, 7 Command generator, 8 Power converter control device, 11 U phase coil, 12 V phase coil , 13 W phase coil, 21 battery, 22 smoothing capacitor, 23 choke coil, 31 switching circuit, 32 current detection circuit, 33 amplification circuit, 34 drive circuit, 81 temperature suppression unit, 82 rotation speed calculation unit, 83 torque / current command Conversion unit, 84 Three-phase two-phase conversion unit, 85 Voltage command generation unit, 86 Two-phase three-phase conversion unit, 87 Duty conversion unit, 88 PWM signal generation unit, 311 to 316 Switching element, 321 U-phase current detection unit, 322 V-phase current detection unit, 323 W-phase current detection unit, 811 Operation availability determination unit, 812 Temperature filter unit, 8 13 Temperature calculation part for gain calculation, 814 Temperature suppression gain calculation part, 815 Limit control command calculation part.

Claims (14)

Power conversion that has one or more switching elements, and each switching element is controlled to be turned on and off, thereby converting the form of power output from the power supply device and outputting the converted power to the load device A control device for controlling the device,
An operation availability temperature is determined based on each measured temperature measured by a switching element temperature sensor that measures the temperature of each switching element, and a temperature suppression operation is started when the operation availability temperature is equal to or higher than a first set threshold. Equipped with a temperature suppressor,
The temperature suppression unit is
The temperature that generates the high response temperature for each measurement temperature by setting each measurement temperature as it is, and the temperature that generates the low response temperature for each measurement temperature by passing each measurement temperature through a low response filter. A filter section;
Based on the high response temperature for each measurement temperature generated by the temperature filter unit, a high response temperature for gain calculation is determined, and based on the low response temperature for each measurement temperature generated by the temperature filter unit A gain calculation temperature determining unit for determining a low response temperature for gain calculation;
The high response temperature suppression gain is calculated so that the high response temperature suppression gain decreases as the gain calculation high response temperature determined by the gain calculation temperature determination unit increases, and is determined by the gain calculation temperature determination unit. The low response temperature suppression gain is calculated so that the low response temperature suppression gain decreases as the gain calculation low response temperature increases, and the temperature suppression is performed from the calculated high response temperature suppression gain and the low response temperature suppression gain. A temperature suppression gain calculator for calculating the gain;
A control command for calculating a limit characteristic value and controlling the characteristic value of the load device by multiplying the rated characteristic value of the load device by the temperature suppression gain calculated by the temperature suppression gain calculation unit. And a limit control command calculation unit that outputs the smaller of the limit characteristic value and the control command as a limit control command by comparing the calculated limit characteristic value;
Have
The controller is
A control device for a power converter, wherein the switching elements of the power converter are switched on and off in accordance with the limit control command output from the limit control command calculator. The temperature filter section is
The control device for a power conversion device according to claim 1, wherein the high response temperature is generated for each measurement temperature by passing each measurement temperature through a high response filter having a cutoff frequency higher than that of the low response filter. . The temperature suppression gain calculator is
The high response temperature suppression gain corresponding to the gain calculation high response temperature determined by the gain calculation temperature determination unit from the high response association between the gain calculation high response temperature and the high response temperature suppression gain. The low response temperature corresponding to the gain calculation low response temperature determined by the gain calculation temperature determination unit from the low response association between the gain calculation low response temperature and the low response temperature suppression gain The control device for the power conversion device according to claim 1 or 2, wherein a suppression gain is calculated. In the association for high response, the high response temperature suppression gain is increased from 1 as the high response temperature for gain calculation changes from the first set threshold value to a second set threshold value higher than the first set threshold value. Set to change to 0,
The low response association is set such that the low response temperature suppression gain changes from 1 to 0 as the gain calculation low response temperature changes from the first set threshold value to the second set threshold value. The control apparatus of the power converter device according to claim 3. 5. The electric power according to claim 1, wherein values of the high response temperature suppression gain and the low response temperature suppression gain calculated by the temperature suppression gain calculation unit are the same or different. Control device for the conversion device. The temperature suppression gain calculator is
When the temperature suppression operation is started, the temperature suppression gain is set as the high response temperature suppression gain, and the temperature suppression gain is changed from the high response temperature suppression gain to the low response temperature at a switching timing after the start of the temperature suppression operation. The control device for the power conversion device according to any one of claims 1 to 5, wherein the control device is switched to a suppression gain. The temperature suppression gain calculator is
The power according to claim 6, wherein, as the switching timing, the temperature suppression gain is switched from the high response temperature suppression gain to the low response temperature suppression gain at a timing when a setting switching time has elapsed since the temperature suppression operation was started. Control device for the conversion device. In the temperature filter unit, an initial value of the high response temperature generated for each measurement temperature and an initial value of the low response temperature generated for each measurement temperature are set to the first set threshold value. It is set. The control apparatus of the power converter device of any one of Claim 1 to 7. The temperature suppression gain calculator is
When the high response temperature suppression gain is αH, the low response temperature suppression gain is αL, the temperature suppression gain is α, and the constant is h, the temperature suppression gain is calculated according to the following formula: α = αH × h + αL × (1-h) where 0 <h <1
The control apparatus of the power converter device of any one of Claim 1 to 8. The temperature suppression gain calculator is
The high response temperature suppression gain is αH, the low response temperature suppression gain is αL, the temperature suppression gain is α, the elapsed time from the start of the temperature suppression operation is t, and the variable that changes with the elapsed time is h _{( t)} , the temperature suppression gain is calculated according to the following equation: α = αH × h _(t) + αL × (1−h _(t) ) where 0 <h _(t) <1
The control apparatus of the power converter device of any one of Claim 1 to 8. The gain calculation temperature determination unit
A maximum value is determined as the high-response temperature for gain calculation from the high-response temperatures for each measurement temperature,
The control device for a power converter according to any one of claims 1 to 10, wherein a maximum value is determined as the gain calculation low response temperature from the low response temperatures for each of the measured temperatures. The temperature suppression unit is
The power conversion device according to any one of claims 1 to 11, wherein the temperature suppression operation is stopped when the low response temperature for gain calculation becomes equal to or lower than the first set threshold value during the temperature suppression operation. Control device. The control device of the power conversion device according to any one of claims 1 to 12, wherein each switching element is configured using a wide band gap semiconductor. Power conversion that has one or more switching elements, and each switching element is controlled to be turned on and off, thereby converting the form of power output from the power supply device and outputting the converted power to the load device A method for controlling an apparatus, comprising:
An operation availability temperature is determined based on each measured temperature measured by a switching element temperature sensor that measures the temperature of each switching element, and a temperature suppression operation is started when the operation availability temperature is equal to or higher than a first set threshold. A temperature suppression step,
The temperature suppression step includes
A step of generating the high response temperature for each measurement temperature by setting each measurement temperature as it is, and generating a low response temperature for each measurement temperature by passing each measurement temperature through a low response filter. When,
Determining a high response temperature for gain calculation based on the generated high response temperature for each of the measured temperatures, and determining a low response temperature for gain calculation based on the low response temperature of the generated each measured temperature When,
The high response temperature suppression gain is calculated so that the high response temperature suppression gain decreases as the determined gain calculation high response temperature increases, and the determined low gain response low response temperature increases the low response temperature suppression gain. Calculating the low response temperature suppression gain so as to reduce the gain, and calculating the temperature suppression gain from the calculated high response temperature suppression gain and the low response temperature suppression gain;
By multiplying the calculated temperature suppression gain by the rated characteristic value of the load device, a limit characteristic value is calculated, and a control command for controlling the characteristic value of the load device and the calculated limit A step of outputting a smaller one of the limit characteristic value and the control command as a limit control command by comparing with a characteristic value;
Have
A control method for a power converter, further comprising a control step of switching each switching element of the power converter to ON and OFF according to the output limit control command.

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