JP2013162732A - Device for controlling vehicle driving motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To promote effectiveness of protection of an inverter by allowing sure sensing of temperature rising of each switching element, while suppressing the number of temperature sensors disposed on the inverter for controlling a three-phase AC motor and having a plurality of the switching elements.SOLUTION: A temperature sensor (25) is installed on only one of a plurality of switching elements (Q11-Q16) that an inverter (2) for controlling a motor (3) has, upon decision of a stalled status of the motor (3), an estimated temperature (TB) obtained by estimating a temperature of one switching element of the highest temperature in the plurality of switching elements (Q11-Q16) is calculated based on a measured temperature (TA) measured by the temperature sensor (25). Then, either the measured temperature (TA) or the estimated temperature (TB) is set as a highest temperature (TH) of the inverter, and inverter protection control is performed when the highest temperature (TH) exceeds a predetermined threshold (TP).

Description

  The present invention relates to a three-phase AC motor as a suitable drive source mounted on a hybrid vehicle or an electric drive vehicle, an inverter having a plurality of switching elements for controlling the three-phase AC motor, and a control means for controlling the inverter. More specifically, the present invention relates to a control device that performs inverter protection control based on the temperatures of a plurality of switching elements.

  An electric vehicle provided with an electric motor (motor) as a drive source and a hybrid type vehicle provided with an electric motor (motor) in addition to an engine as a drive source are known. In this type of electric vehicle or hybrid vehicle, it is common to drive a motor by converting DC power from a DC power source (battery) into AC power by a power converter such as an inverter. In the hybrid vehicle, the vehicle is driven by any one of an engine traveling alone using the engine alone, a motor traveling alone using only the electric motor, and a hybrid vehicle traveling by combining the engine and the motor. It has become.

  When the electric vehicle is traveling as described above or when the motor is traveling alone on a hybrid vehicle, the rotation of the motor is locked by an external force (stall state), such as when the vehicle remains stationary on the slope and does not move back and forth at all It may become. In such a motor stall state, a phenomenon called in-phase energization occurs in which current concentrates on only one phase of the stator windings of the plurality of phases of the motor. Therefore, when the stall condition lasts for a long time, among the switching elements provided in the power converter (inverter), the current concentrated phase switching elements generate heat, and the temperature rises beyond the allowable range. As a result, the switching element may be damaged by heat.

  As a conventional technique for dealing with such a stalled state of the motor, for example, in the drive control device for an electric vehicle disclosed in Patent Document 1, when the stalled state continues beyond the allowable time, the vehicle travels. Torque reduction processing is performed to protect power circuits such as motors and inverters, and the reverse speed of the vehicle is limited when torque command reduction control is performed.

  An IGBT (Insulated Gate Bipolar Transistor), which is a switching element included in the inverter, flows a high current necessary for running the vehicle to the electric motor. High risk of high temperature. Therefore, in order to effectively protect the inverter, it is necessary to monitor the temperature of the IGBT with high accuracy. Therefore, in an inverter having a conventional IGBT, a temperature sensor is attached to each of a total of six switching elements of the U phase, the V phase, and the W phase on the positive electrode side and the negative electrode side of the IGBT. However, in this configuration, there is a problem that the cost of the vehicle increases due to the large number of temperature sensors. That is, from the viewpoint of vehicle cost reduction, it is necessary to suppress the number of temperature sensors installed in the IGBT as small as possible.

  However, if the number of temperature sensors installed in the IGBT is less than the number of switching elements, there will be switching elements in which no temperature sensor is installed. In this configuration, if in-phase energization occurs while the motor is stalled, the temperature of the switching elements of phases other than the phase on which the temperature sensor is mounted may rise beyond the allowable range. If it does so, the said temperature rise cannot be detected appropriately and there exists a possibility that the protection of an inverter may not be aimed at effectively.

  As a conventional technique related to inverter temperature detection, there is an electric vehicle control device described in Patent Document 2. In this electric vehicle control device, one temperature sensor for detecting the temperature of the switching element in the inverter is installed for a plurality of switching elements, and the temperature sensor includes a plurality of switching elements. The temperature is monitored. For this reason, when the temperature of the switching element at a position away from the measurement location of the temperature sensor rises, there is a problem that detection of the temperature rise is delayed because it takes time to transmit the temperature.

JP 7-336807 A Japanese Patent No. 3732416

  The present invention has been made in view of the above-described points, and an object of the present invention is to reliably detect a temperature increase of a plurality of switching elements included in an inverter while suppressing the number of temperature sensors installed in the inverter. Thus, an object of the present invention is to provide a control device for a motor for driving a vehicle that can effectively protect an inverter.

  In order to solve the above problems, the present invention provides a three-phase AC motor (3) as a vehicle drive source and an inverter having a plurality of switching elements (Q11 to Q16) for controlling the three-phase AC motor (3) ( 20) and a control device (10) for controlling the inverter (20), the control device for the motor for driving the vehicle, wherein a number smaller than the number of the plurality of switching elements (Q11 to Q16) is installed. Based on the temperature sensor (25), the stall state determining means for determining the stall state of the electric motor (2), and the measured temperature (TA) measured by the temperature sensor (25), the plurality of switching elements (Q11 to Q16) Temperature estimation means for calculating an estimated temperature (TB) obtained by estimating the temperature of the switching element having the highest temperature among them, and the control means (10) includes a stall state determination means. When the stall state of the electric motor (3) is determined, either the measured temperature (TA) measured by the temperature sensor (25) or the estimated temperature (TB) estimated by the temperature estimating means is set to the maximum temperature of the inverter ( TH) is set, and when the maximum temperature (TH) becomes equal to or higher than a predetermined threshold value (TP), predetermined protection control for the inverter (20) is performed.

  According to the control apparatus for a vehicle driving motor according to the present invention, by providing the temperature sensor having a number smaller than the number of the plurality of switching elements, the number of the temperature sensors to be installed can be suppressed to be low. This can contribute to cost reduction. Based on the measured temperature measured by the temperature sensor, an estimated temperature obtained by estimating the temperature of the switching element having the highest temperature among the plurality of switching elements is calculated. As a result, when determining the stall state of the electric motor, the temperature of either the measured temperature measured by the temperature sensor or the estimated temperature estimated by the temperature estimating means is set to the maximum temperature of the inverter, and the maximum temperature exceeds a predetermined value. Then, predetermined protection control for the inverter is performed. As described above, by estimating the temperature of the switching element and determining the maximum temperature of the inverter, it is possible to detect the temperature increase of the plurality of switching elements included in the inverter with high accuracy. Therefore, appropriate inverter protection control can be performed before the temperature of the switching element rises beyond the allowable range, and the effectiveness of inverter protection when the motor is stalled can be enhanced.

  Further, in the above vehicle drive motor control device, the inverter protection control by the control means (10) may be a motor torque limit for limiting the output torque of the motor (3).

  According to this configuration, by limiting the output torque when the motor is stalled, it is possible to reduce the power entering the inverter from the power source. Thereby, the temperature rise of the switching element which the inverter has can be suppressed and the inverter can be protected. In addition, when the motor stalls while the vehicle is traveling uphill, the vehicle moves rearward (below the uphill) under its own weight if the output torque of the motor driving the vehicle is limited ( The energized phase of the electric motor is switched. After that, if the accelerator opening is increased by the driver's depression of the accelerator pedal, the driving force of the motor will increase again. At that time, the energized phase of the motor has already been switched, so that the vehicle can run by driving the motor. It becomes.

  Further, in the above vehicle drive motor control device, the temperature estimation means has a plurality of temperature change rate data (L1 to L3) having different rates of increase for each required torque of the motor (3) prepared in advance. The rising side estimated temperature (TB1) is calculated based on any temperature change rate data selected according to the required torque of the electric motor (3), and the control means (10) When the stall state of (3) is determined, the measured temperature (TA) is compared with the rising side estimated temperature (TB1). If the rate of temperature increase does not match, the rising side estimated temperature (TB1) is set. It may be set as the maximum temperature (TH) of the inverter.

  According to this configuration, it is possible to calculate an appropriate estimated temperature according to the required torque of the motor by switching data of a plurality of temperature change rates having different rates of increase according to the required torque of the motor. That is, the rate of temperature increase of the switching element of the inverter changes according to the current flowing from the inverter to the motor, but the current changes according to the required torque of the motor. Therefore, if the estimated temperature is calculated by switching the temperature change rate data as described above, even if the temperature of the switching element not provided with the temperature sensor is increased, the temperature of the switching element is increased from the required torque of the motor. As a result, the inverter can be effectively protected.

  Further, in the above-described vehicle drive motor control device, the temperature sensor (25) is provided in two or more of the plurality of switching elements (Q11 to Q16), and the control means (10) is a stall state determination means. If the measured temperature of one temperature sensor is constant when determining the stall state of the electric motor (3), one of the measured temperature (TA) and estimated temperature (TB) of the other temperature sensor is It may be set as the maximum temperature (TH).

  According to this configuration, when the temperature sensor is provided in two or more of the plurality of switching elements, when the temperature of the switching element provided with the one temperature sensor is not increased, another temperature sensor is provided. The temperature of the provided switching element or the estimated temperature by the temperature estimating means is set as the maximum temperature of the inverter. Thereby, it becomes possible to detect the temperature of a plurality of switching elements with higher accuracy.

  The control device for a vehicle driving motor according to the present invention includes a three-phase AC motor (3) as a vehicle drive source and a plurality of switching elements (Q11 to Q16) for controlling the three-phase AC motor (3). And a control means (10) for controlling the inverter (20), the control device for the motor for driving the vehicle, wherein only one of the plurality of switching elements (Q11 to Q16) is provided. Based on the temperature sensor (25) provided, the stall state determination means for determining the stall state of the electric motor (3), and the measured temperature (TA) measured by the temperature sensor (25), a plurality of switching elements (Q11 to Q11) are provided. Q16), and a temperature estimation means for calculating an estimated temperature (TB) obtained by estimating the temperature of the switching element having the highest temperature. When the output torque of 3) is present and the rotation of the electric motor (3) is substantially stopped and the energized phase does not change, it is determined that the electric motor (3) is in a stalled state, and the control means (10) When the judging means detects the stall state of the electric motor (3), one of the measured temperature (TA) of the temperature sensor (25) and the estimated temperature (TB) of the temperature estimating means is set to the maximum temperature (TH of the inverter). When the maximum temperature (TH) becomes equal to or higher than a predetermined threshold value (TP), motor torque limitation is performed to limit the output torque of the motor as protection control for the inverter.

  According to this configuration, by providing the temperature sensor only in one of the plurality of switching elements, it is possible to reduce the number of temperature sensors to be installed and contribute to cost reduction of the vehicle. Based on the measured temperature measured by the temperature sensor, an estimated temperature obtained by estimating the temperature of the switching element having the highest temperature among the plurality of switching elements is calculated. As a result, when determining the stall state of the electric motor, the temperature of either the measured temperature measured by the temperature sensor or the estimated temperature estimated by the temperature estimating means is set to the maximum temperature of the inverter, and the maximum temperature exceeds a predetermined value. Then, predetermined protection control for the inverter is performed. As described above, by estimating the temperature of the switching element and determining the maximum temperature of the inverter, it becomes possible to detect the temperature rise of the plurality of switching elements included in the inverter with high accuracy. Therefore, inverter protection control can be performed before the temperature of the switching element rises beyond the allowable range, and the effectiveness of inverter protection when the motor is stalled can be enhanced. Further, by limiting the output torque of the motor as the inverter protection control when the motor is stalled, the power entering the inverter from the power source can be reduced. Thereby, the temperature rise of the switching element which an inverter has can be suppressed.

  Further, in the above vehicle drive motor control device, the temperature estimation means includes a plurality of current concentration phase temperature change models (L1 to L3) having different rates of increase for each required torque of the motor (3). The rising side estimated temperature (TB1) is calculated based on one of the temperature change models selected according to the required torque of the electric motor (3), and the control means (10) is configured so that the stall state determining means is the electric motor (3). When the stall state is determined, the measured temperature (TA) is compared with the rising side estimated temperature (TB1), and when the rate of temperature increase is different, the rising side estimated temperature (TB1) is determined as the maximum inverter temperature. It may be set as (TH).

  According to this configuration, control is performed to calculate the estimated temperature based on the temperature of the temperature change model by switching the current change phase temperature change model having a different rate of increase for each required torque of the motor. That is, the rate of temperature rise of the switching element of the inverter changes according to the current flowing from the inverter to the motor, but the current changes with the required torque of the motor, so the temperature change model according to the required torque as described above is used. Control by switching. Thereby, when the temperature of the switching element not provided with the temperature sensor is increased, the temperature increase of the switching element can be accurately predicted from the required torque of the electric motor, so that the inverter is effectively protected. be able to.

  The vehicle drive motor control device includes a brake (37) for braking the drive wheels (WR, WL) of the vehicle (1), and the control means (10) controls the motor as an inverter protection control. Before limiting the output torque, it is preferable to start braking of the drive wheel by operating the brake.

  As described above, when the motor stalls due to a balance between the maximum torque of the motor and the climbing torque while the vehicle is traveling uphill, if the output torque of the motor is limited as an inverter protection control, the vehicle There is a risk of moving backward (downward) under its own weight. However, it is less desirable for the vehicle to move backward on an uphill from the viewpoint of safety. Therefore, as described above, before limiting the output torque of the electric motor, it is preferable to start driving wheel braking (coordinate control of the brake with respect to the electric motor) by operating the brake. As a result, even when the output torque of the electric motor is limited as protection control for the inverter, the vehicle can be held at the same position to prevent backward movement (sliding down).

  Further, in the above-described vehicle drive motor control device, an internal combustion engine (2) as a drive source of the vehicle (1) and a power transmission path for transmitting power between the motor (3) and the internal combustion engine (3). (4), and when the vehicle (1) travels only with the driving force of the electric motor (3), when the output torque of the electric motor (3) is limited as inverter protection control, The internal combustion engine (2) may be started with a current machine (3) via 4).

  According to this configuration, when the vehicle is running only with the driving force of the electric motor, if the motor stalls, if the internal combustion engine is started when limiting the output torque of the electric motor as the inverter protection control, Thereafter, the vehicle can continue to travel using the driving force of the internal combustion engine, so that the vehicle travel is not hindered.

  In the above vehicle drive motor control device, when the stall state determination means determines the stall state of the electric motor (3), when the determination of the stall state is cancelled, the measured temperature (TA) and the increase side The difference temperature (dT1) from the estimated temperature (TB1) is calculated, and after the difference temperature (dT1) is calculated, until the next stall state is determined, the difference temperature (dT1) is constant with respect to the elapsed time. The estimated temperature (TB) may be a descending estimated temperature (TB2) that is a value decreased at a change rate (−α).

  According to this configuration, an appropriate temperature corresponding to the actual temperature of the inverter (switching element) can be calculated as the estimated temperature after the determination of the stall state is canceled. It can be predicted and the inverter can be effectively protected.

  In this case, until the descending side estimated temperature (TB2) becomes equal to or lower than the measured temperature (TA), the descending side estimated temperature (TB2) is set as the estimated temperature (TB), and the descending side estimated temperature (TB2) is the measured temperature (TB). When the temperature becomes less than (TA), the measured temperature (TA) may be set to the estimated temperature (TB).

  According to this configuration, since the estimated temperature is calculated as a temperature closer to the actual temperature of the inverter (switching element), even when the motor stalls again, the temperature rise of the inverter can be detected more safely. Therefore, the effectiveness of inverter protection control can be further enhanced.

  In this case, in the calculation of the estimated temperature (TB) after the next stall state is determined, the measured temperature (TA) measured by the temperature sensor (25) is the estimated lower side temperature (TB2) when the stall state is determined. The estimated temperature (TB) may be calculated by replacing

When the determination of the stall state is canceled in a state where the inverter temperature has risen, the above-mentioned lower side estimated temperature will be used as the estimated temperature after that, but in that case, when the motor stalls again, for example, If current concentration occurs in the switching element in phase with the previous stall, an error may occur between the estimated temperature based on the temperature measured by the temperature sensor and the actual maximum temperature of the inverter. Therefore, in order to prevent such an error from occurring, when the stall state determination is canceled while the inverter temperature has risen, the temperature measured by the temperature sensor is the estimated temperature on the lower side when the stall state is determined. It is better to calculate the estimated temperature after that. Thereby, since the accuracy of the estimated temperature to be calculated can be increased, the inverter can be protected more effectively.
In addition, the code | symbol in said parenthesis shows the code | symbol of the component in embodiment mentioned later as an example of this invention.

  According to the control apparatus for a vehicle driving motor according to the present invention, the temperature increase of each switching element can be reliably detected while suppressing the number of temperature sensors installed in the inverter, thereby protecting the inverter. Effectiveness can be increased.

1 is a schematic diagram illustrating a configuration example of a hybrid vehicle including a vehicle drive motor control device according to an embodiment of the present invention. It is a circuit diagram which shows a battery, a motor, and an inverter. It is a flowchart for demonstrating the procedure of motor stall determination and inverter protection control. It is a graph which shows the phase current waveform which flows into an inverter and a motor at the time of a motor stall, a motor stall flag, and the temperature change of the switching element of an inverter. (A) is a graph for demonstrating the detail of temperature rise estimation, (b) is a graph for demonstrating the detail of temperature fall estimation. 5 is a timing chart showing changes in various values such as a vehicle speed, an accelerator pedal opening degree, and a temperature estimation value of a switching element before and after a motor stall occurs.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic diagram illustrating a configuration example of a vehicle including a vehicle drive motor control device according to an embodiment of the present invention. As shown in FIG. 1, the vehicle 1 of the present embodiment is a hybrid vehicle equipped with an engine 2 and an electric motor 3 as drive sources, and further an inverter (electric motor control means) for controlling the electric motor 3. 20, a battery 30, a transmission (transmission) 4, a differential mechanism 5, left and right drive shafts 6R and 6L, and left and right drive wheels WR and WL. Here, the electric motor 3 is a motor and includes a motor generator, and the battery 30 is a capacitor and includes a capacitor. The internal combustion engine 2 is an engine, and includes a diesel engine, a turbo engine, and the like. The rotational driving force of the internal combustion engine (hereinafter referred to as “engine”) 2 and the electric motor (hereinafter referred to as “motor”) 3 is driven to the left and right via the transmission 4, the differential mechanism 5 and the drive shafts 6R and 6L. It is transmitted to the wheels WR and WL.

  The vehicle 1 also includes an electronic control unit (ECU) 10 for controlling the engine 2, the motor 3, the transmission 4, the differential mechanism 5, the inverter (electric motor control means) 20, and the battery 30. The electronic control unit 10 is not only configured as a single unit, but also, for example, an engine ECU for controlling the engine 2, a motor generator ECU for controlling the motor 3 and the inverter 20, and a battery for controlling the battery 30. The ECU may be composed of a plurality of ECUs such as an AT-ECU for controlling the transmission 4. The electronic control unit 10 according to the present embodiment controls the engine 2 and also controls the motor 3, the battery 30, and the transmission 4.

  The electronic control unit 10 performs control so that the motor alone travels (EV travel) using only the motor 3 as a power source according to various operating conditions, or performs the engine alone travel using only the engine 2 as a power source. Control is performed so as to perform cooperative traveling (HEV traveling) in which both the engine 2 and the motor 3 are used as power sources. Further, the electronic control unit 10 performs protection control of the inverter 20 in a stalled state of the motor 3 described later and other control necessary for various operations according to various known control parameters.

  In addition, the electronic control unit 10 includes, as control parameters, the accelerator pedal opening from the accelerator pedal sensor 31 that detects the depression amount of the accelerator pedal, and the brake pedal opening from the brake pedal sensor 32 that detects the depression amount of the brake pedal. The shift position from the shift position sensor 33 that detects the gear stage (shift stage), the motor rotation speed from the rotation speed sensor 34 that detects the rotation speed of the motor 3, and the inclination angle sensor 35 that detects the inclination of the vehicle 1 Various signals such as an inclination angle and a measured temperature from a temperature sensor 25 that measures the temperature of a switching element Q14 (described later) in the inverter 20 are input.

  The engine 2 is an internal combustion engine that generates driving force for running the vehicle 1 by mixing fuel with air and burning it. The motor 3 functions as a motor that generates a driving force for running the vehicle 1 using the electric energy of the battery 30 when the engine 2 and the motor 3 are collaboratively run or when the EV 3 is driven only by the motor 3. In addition, when the vehicle 1 is decelerated, it functions as a generator that generates electric power by regeneration of the motor 3. During regeneration of the motor 3, the battery 30 is charged with electric power (regenerative energy) generated by the motor 3.

  FIG. 2 is a circuit diagram showing the motor 3 and the inverter 20 shown in FIG. As shown in the figure, the inverter 20 is a power converter including a U-phase arm 21, a V-phase arm 22, and a W-phase arm 23. Each phase arm of the inverter 20 is composed of switching elements connected in series to a battery power line L for supplying power from the battery 30. For example, the U-phase arm 21 includes switching elements Q11 and Q12, the V-phase arm 22 includes switching elements Q13 and Q14, and the W-phase arm 23 includes switching elements Q15 and Q16. The switching elements Q11 to Q16 are power semiconductor switching elements such as an IGBT (Insulated Gate Bipolar Transistor), a power MOS (Metal Oxide Semiconductor) transistor, or a power bipolar transistor. Anti-parallel diodes D11 to D16 are connected to these switching elements Q11 to Q16, respectively. On / off of the switching elements Q11 to Q16 is controlled by a switching control signal from the electronic control unit 10.

  And the temperature sensor 25 for measuring the temperature of the one switching element Q14 is provided. The temperature sensor 25 is disposed adjacent to the switching element Q14, and the temperature of the switching element Q14 measured by the temperature sensor 25 is output to the ECU 10 via the detection circuit 27. In the present embodiment, one of the six switching elements Q11 to Q16 provided in the U-phase arm 21, V-phase arm 22, and W-phase arm 23 of the inverter 20 is used to measure the temperature of one switching element Q14. Only the temperature sensor 25 is provided.

  The motor 3 is a brushless DC motor such as a permanent magnet type three-phase AC motor using a permanent magnet as a field, for example, and includes a U-phase coil winding U1, a V-phase coil winding V1, and a W-phase provided on a stator. A coil winding W1 and a rotor (not shown) are included. One ends of the U-phase coil winding U1, the V-phase coil winding V1, and the W-phase coil winding W1 are connected to each other at a neutral point N1, and the other ends are connected to the U-phase arm 21, V-phase arm 22 and W of the inverter 20. Each is connected to the phase arm 23.

  The inverter 20 performs bidirectional power conversion between the battery 30 and the motor 3 by on / off control (switching control) of the switching elements Q11 to Q16 in response to the switching control signal from the electronic control unit 10. Specifically, inverter 20 converts a DC voltage received from battery 30 into a three-phase AC voltage according to switching control by electronic control unit 10, and outputs the converted three-phase AC voltage to motor 3. As a result, the motor 3 is driven to generate a designated torque. Further, the inverter 20 converts the three-phase AC voltage generated by the motor 3 in response to the output of the engine 2 into a DC voltage according to switching control by the electronic control unit 10, and outputs the converted DC voltage to the battery 30. it can.

  In the present embodiment, particularly when the stall state of the motor 3 is determined as the driving state of the vehicle 1, the temperature of the inverter 20 (switching elements Q11 to Q16) is detected, and predetermined motor protection control is performed based on the detection of the temperature. This prevents the occurrence of a failure due to heat in the inverter 20 (switching elements Q11 to Q16). Hereinafter, the content of the protection control will be described in detail.

  FIG. 3 is a flowchart for explaining the procedure of the stall determination of the motor 3 and the inverter protection control. FIG. 4 shows the waveform of the phase current flowing through the inverter 20 and the motor 3 and the motor stall flag when the motor 3 is stalled. It is a graph which shows the change of (stall judgment flag), and the temperature change of the inverter 20 (switching elements Q11-Q16). Hereinafter, the inverter protection control performed when the motor 3 is stalled will be described with reference to these drawings. The control shown in the flowchart of FIG. 3 is performed during EV travel (motor single travel), which is vehicle travel using only the motor 3. During EV traveling, a current exceeding a certain level is supplied to the motor 3, and the motor 3 is in a state of generating torque. 4 is estimated based on the measured value of the temperature of the switching element Q14 measured by the temperature sensor 25 (hereinafter referred to as “measured temperature TA”) and the measured temperature TA. The maximum temperature of the inverter 20 (which indicates the maximum temperature of the switching elements Q11 to Q16 included in the inverter 20, the same shall apply hereinafter) TH is referred to as an estimated value (hereinafter, “estimated temperature TB”). ) And the actual maximum temperature (hereinafter referred to as “actual temperature TC”) of the switching elements Q11 to Q16 in the current concentrated phase of the inverter 20. In this graph, the measured temperature TA is indicated by a one-dot chain line, of the estimated temperature TB, a rising estimated temperature TB1, which will be described later, is indicated by a thick solid line, a decreasing estimated temperature TB2 is indicated by a dotted line, and the actual temperature TC is indicated by a thin solid line. Show.

  Here, calculation of the estimated temperature TB that is an estimated value of the maximum temperature TH of the inverter 20 will be described. First, calculation of the estimated temperature TB (rising side estimated temperature TB1) when the motor 3 is stalled (when the stall flag is ON) will be described. FIG. 5A is a graph showing a temperature change (temperature increase) used for calculating the estimated temperature TB when the motor 3 prepared in advance is stalled. Here, the temperature increase rate of the inverter 20 during the stall is divided into a temperature change rate (slope) A in the initial stage of the stall and a temperature change rate (slope) B in the subsequent temperature saturation state. And the temperature change rate B are prepared as a plurality of types of estimated values corresponding to the required torque of the motor 3 at the time of stall. In the illustrated example, three types of temperature change lines L1 to L3 are prepared as graphs of the temperature change of the inverter 20 assumed when the required torque of the motor 3 at the time of stall is large, medium, and small, respectively. doing. That is, a map of the temperature rise of the inverter 20 is set for each required torque of the motor 3 at the time of stall.

  Then, in order to calculate the estimated temperature TB when the motor 3 is stalled, a change in temperature rise of any of the three types of lines L1 to L3 shown in FIG. A line having a rate is selected, and the estimated temperature TB1 shown in FIG. 4 is calculated using the value on the line. Specifically, the measured temperature TA at the time when the stall determination of the motor 3 is determined (when the stall flag is ON) is set as the initial temperature T0, and changes from the initial temperature T0 at the temperature change rate A and the temperature change rate B ( The temperature that rises is assumed to be the rising side estimated temperature TB1. The temperature selected as the rising side estimated temperature TB1 is always set to be higher than the actual temperature TC. That is, the actual temperature TC is set so as not to exceed the rising side estimated temperature TB1.

  Next, calculation of the estimated temperature TB (decrease-side estimated temperature TB2) during stall release of the motor 3 (when the stall flag is OFF) will be described. FIG. 5B is a graph showing a temperature change (temperature decrease) used for calculating the estimated temperature TB during the stall release of the motor 3. Estimated temperature TB (descent-side estimated temperature TB2) during stall release (destination release of stall determination) is based on the difference temperature dT1 between the estimated temperature TB and the measured temperature TA at the time (t31) when the stall determination flag is turned off. It is assumed that it falls with a predetermined time constant (α). That is, the estimated temperature TB during stall release is a value represented by TB = dT1-αt. Here, t is an elapsed time since the stall release of the motor 3 (t31). If the lower side estimated temperature TB2 becomes equal to or lower than the measured temperature TA (TA ≧ TB2) during the stall release determination, the maximum temperature TH of the inverter 20 is changed from the lower side estimated temperature TB2 to the measured temperature TA at that time (t32). Try to change. The descending side estimated temperature TB calculated in this way is set as the estimated temperature TB (temperature change indicated by a dotted line) during stall release (t22 to t23) shown in FIG.

  Further, as shown in the graph of FIG. 4, during the stall release of the motor 3 (t22 to t23), the stall determination of the motor 3 is again performed before the lower side estimated temperature TB2 falls below the measured temperature TA (TA ≧ TB). In the case (t23), the value (TB = dT1-αt) of the estimated descent temperature TB2 at that time is set as a new initial temperature T0, and the temperature change shown in FIG. 5 (a) from the initial temperature T0. The temperature that changes (increases) at the rate A and the temperature change rate B is set as the estimated temperature TB during this stall (rising side estimated temperature TB1). Thereafter, an estimated temperature TB that is an estimated value of the maximum temperature TH of the inverter 20 during the stall of the motor 3 and during the release of the stall is calculated by the same method.

  Next, the procedure for determining the stall state of the motor 3 and the inverter protection control will be described with reference to the flowchart of FIG. In the control flow shown in FIG. 3, first, the stall state of the motor 3 is determined (step ST1). The determination of the stall state of the motor 3 is made when the motor 20 is energized for a predetermined time by the inverter 20 and there is an output torque of the motor 3 and the motor 3 is substantially stopped (the rotation of the motor 3). If the number is substantially zero) and it is determined that the energized phase does not change, it is determined that the motor 3 is in a stalled state. That is, in this case, since current may continue to flow through any of the switching elements Q11 to Q16 of the inverter 20 corresponding to the energized phase of the motor 3, excessive local heat generation may occur. To do.

  Further, the determination of the stall state of the motor 3 is based on whether the inclination of the vehicle 1 is equal to or larger than a predetermined value and the rotational speed of the motor 3 is equal to or smaller than the predetermined rotational speed according to the inclination angle of the vehicle 1 and the rotational speed of the motor 3. You may judge by. That is, it is determined whether or not the vehicle 1 is in a state where the vehicle 1 does not move back and forth while the vehicle 1 is stationary in the middle of the hill, even though a certain current or more is supplied to the motor 3. When it is determined that the inclination of the vehicle 1 is equal to or greater than a predetermined value and the rotation speed of the motor 3 is equal to or less than the predetermined rotation speed, it is determined that the motor 3 is in a stalled state.

  As a result of the stall determination (step ST1), when it is determined that the motor 3 is in a stalled state (YES), in calculating the maximum temperature TH of the inverter 20, the rising side temperature estimation (the rising side estimated temperature TB1) is continued. It is determined whether or not to execute (calculation) (step ST2). This determination is made based on a comparison between the measured temperature TA measured by the temperature sensor 25 and the rising side estimated temperature TB1 that is the estimated temperature TB in the stall state. Specifically, it is determined whether or not the change rate (slope) of the measured temperature TA follows the change rate (slope) of the rising side estimated temperature TB1. As a result, if the change rate of the measured temperature TA does not follow the change rate of the rising side estimated temperature TB1, the rising side temperature estimation is not performed (NO), and the temperature sensor 25 measures the maximum temperature TH of the inverter 20. The temperature TA is input (step ST3). On the other hand, if the change rate of the measured temperature TA follows the change rate of the rising side estimated temperature TB1, the rising side temperature is estimated (YES), and the rising side estimated temperature TB1 is input as the maximum temperature TH of the inverter 20. (Step ST4).

  Subsequently, it is determined whether or not the gradient of the temperature rise of the rising side estimated temperature TB1 input in step ST4 is large (step ST5). As a result, if the slope of the temperature rise is large (YES), the temperature on the map is searched using the map of the large slope of the temperature change (the line of the temperature change L1 shown in FIG. 5A) ( Step ST6). Specifically, the maximum temperature on the map with a large inclination is searched. On the other hand, if the slope of the temperature rise is small (NO), the temperature on the map is searched using the map of the small slope of the temperature change (the line of the temperature change L3 shown in FIG. 5A) (step). ST7). Also in this case, specifically, the maximum temperature on the map with a small inclination is searched. In addition, although the case where two types of large and small gradients are set as the gradient of the temperature rise is illustrated here, other than this, for example, as shown in L1 to L3 in FIG. Three or more types of inclinations may be set as the upward inclination. Further, here, as the line of the temperature change L1 shown in FIG. 5A, the temperature change rate (slope) A in the initial stage of the stall and the temperature change rate (slope) B in the subsequent temperature saturation state are set for a certain time. It can be switched and used every time.

  On the other hand, if there is no stall determination in the previous step ST1 (NO), it is determined whether or not the lower side temperature estimation (calculation of the lower side estimated temperature TB2) is necessary (step ST8). This determination is made based on a comparison between the measured temperature TA measured by the temperature sensor 25 and the estimated lower side temperature TB2 that is the estimated temperature TB in the stall release state. Specifically, it is determined whether or not the rate of change (slope) of the measured temperature TA follows the rate of change (slope) of the estimated lower side temperature TB2. As a result, if the rate of change of the measured temperature TA follows the rate of change of the descending side estimated temperature TB2, the descending side temperature estimation is unnecessary (NO). In that case, as the maximum temperature TH of the inverter 20, The measurement temperature TA of the temperature sensor 25 is input (step ST9). On the other hand, if the rate of change of the measured temperature TA does not follow the rate of change of the descending estimated temperature TB2, the descending temperature estimate is necessary (YES). In this case, the maximum temperature of the inverter 20 at the time of stall release The estimated lower side temperature TB2 is input as TH (step ST10).

  Subsequently, in step ST11, the estimated rising temperature TB1 calculated in step ST6 or ST7, the measured temperature TA on the rising side (during stall) input in step ST3, the estimated decreasing side temperature TB2 calculated in step ST9, step ST10. The highest temperature TH of the inverter 20 is determined by setting one of the measured temperatures TA on the descending side (during stall release) input in step S5 as the highest temperature TH (step ST11). Thereafter, the maximum temperature TH is compared with an inverter protection threshold temperature TP used for determining whether or not to perform inverter protection control (step ST12). As a result, if the maximum temperature TH is less than the inverter protection threshold temperature TP (maximum temperature TH <inverter protection threshold temperature TP) (NO), the process is terminated without performing inverter protection control, while the maximum temperature TH is inverter protection. If the temperature is equal to or higher than the threshold temperature TP (maximum temperature TH ≧ inverter protection threshold temperature TP) (YES), inverter protection control is performed (step ST13). The specific content of the inverter protection control here starts with the operation of the brake 37 (coordinate control of the brake 37 with respect to the motor 3) for braking the drive wheels WR and WL of the vehicle 1 and then the motor 3 Control to limit output torque. The limitation on the output torque of the motor 3 is specifically the limitation on the drive current value of the motor 3.

  FIG. 6 is a timing chart showing changes in various values before and after the motor 3 stalls. The timing chart of the figure shows vehicle speed V, accelerator pedal opening, brake pedal opening, motor torque (motor output torque), brake torque, stall determination flag F_ST, and temperature threshold value for performing inverter protection control at the time of stall ( Changes with respect to the elapsed time of the inverter protection threshold temperature TP), the maximum temperature TH of the inverter 20 (estimated temperature TB), and the inverter protection control request flag F_IB are shown. The inverter protection threshold temperature TP is set such that the upper limit value TP1 and the lower limit value TP2 are different from each other. Hereinafter, the control contents when the motor 3 is stalled will be described with reference to this timing chart. In the following description, the step numbers of the corresponding processes in the flowchart of FIG. 4 are also shown.

  When the vehicle is traveling with only the driving force of the motor 3 (EV traveling), if the vehicle speed V decreases and the motor 3 is stalled in the middle of an uphill, the motor 3 is stalled (step 11). YES is made in ST1. At that time, estimation of the maximum temperature TH of the inverter 20 (calculation of the estimated temperature TB) is started (step ST4). Thereafter, when the maximum temperature TH of the inverter 20 becomes equal to or higher than the inverter protection threshold temperature (upper limit value) TP1 at time t12 (YES in step ST12), the inverter temperature protection request flag F_IB is turned ON. Accordingly, the application of brake torque (brake cooperative control) is started at time t13, and the drive wheels WR and WL are braked. Furthermore, control which restrict | limits the output torque of the motor 3 is started at the time t14 after provision of brake torque is performed. Thereafter, when the output torque of the motor 3 becomes 0 at time t15, the stall determination flag F_ST is turned OFF. Furthermore, when the maximum temperature TH of the inverter 20 becomes equal to or lower than the inverter protection threshold temperature (lower limit value) TP2 at time t16, the inverter temperature protection request flag F_IB is turned OFF. Thereafter, the vehicle 1 starts traveling again.

  As described above, in the vehicle drive motor control device according to the present embodiment, as inverter protection control, before the output torque of the motor 3 is limited, the braking of the drive wheels WR and WL by the operation of the brake 37 (the brake for the motor 3) Cooperative control) is started.

  When stalling occurs in the motor 3 due to the balance between the maximum torque of the motor 3 and the climbing torque while the vehicle 1 is traveling uphill, if the output torque of the motor 3 driving the vehicle 1 is limited, the vehicle 1 May move backward (downhill) under its own weight. However, it is not very desirable for the vehicle 1 to move backward on an uphill from the viewpoint of safety. Therefore, in the present embodiment, as described above, before the output torque of the motor 3 is limited, braking of the drive wheels WR and WL by the operation of the brake 37 (coordinate control of the brake with respect to the motor 3) is started. . Thereby, even when the output torque of the motor 3 is limited as the inverter protection control, the vehicle 1 can be held at the same position to prevent the backward movement (sliding down).

  Although illustration is omitted, control for starting the engine 2 by driving the motor 3 may be performed when limiting the output torque of the motor 3 as inverter protection control. According to this, when the vehicle 1 is driven only by the driving force of the motor 3 (during EV traveling), if the motor 3 is stalled, even if the output torque of the motor 3 is limited as inverter protection control. Thereafter, the vehicle 1 can continue to travel with the driving force of the engine 2. Therefore, there is no need to hinder the traveling of the vehicle 1.

  As described above, in the vehicle drive motor control device of the present embodiment, the temperature sensor 25 is provided only in one switching element Q14 among the plurality of switching elements Q11 to Q16 included in the inverter 20, The cost of the vehicle 1 is reduced by reducing the number of temperature sensors to be installed. Then, based on the measured value (measured temperature TA) of the temperature of the switching element Q14 by the temperature sensor 25, an estimated temperature TB is calculated by estimating the temperature of the switching element having the highest temperature among the plurality of switching elements Q11 to Q16. I am doing so. Thus, when the stall state of the motor 3 is determined, one of the measured temperature TA measured by the temperature sensor 25 and the estimated temperature TB estimated based on the measured temperature TA is set as the maximum temperature TH of the inverter 20. When the maximum temperature TH becomes equal to or higher than a predetermined value (inverter protection threshold temperature TP), predetermined protection control for the inverter 20 is performed. Thus, by determining the maximum temperature TH of the inverter 20 using the estimated temperature TB estimated based on the measured temperature TA by the one temperature sensor 25, the temperature rise of the inverter 20 including the plurality of switching elements Q11 to Q16. Can be detected with high accuracy. Accordingly, since appropriate protection control can be performed before the temperature of the inverter 20 rises beyond the allowable range, the effectiveness of inverter protection when the motor 3 is stalled can be enhanced.

  Moreover, in this embodiment, the electric power which enters into the inverter 20 from the battery (power supply) 30 can be restrained small by performing control which restrict | limits the output torque of the motor 3 as inverter protection control at the time of stall determination. Thereby, the temperature rise of switching elements Q11-Q16 which inverter 20 has can be controlled, and protection of inverter 20 can be aimed at.

  Moreover, in this embodiment, as shown to Fig.5 (a), it has the data (L1-L3) of the several temperature change rate which has a different raise rate for every required torque of the motor 3 prepared beforehand, The estimated temperature TB (rising side estimated temperature TB1) is calculated using the data of the temperature change rate selected from them according to the required torque of the motor 3. Then, when the stall state of the motor 3 is determined, the measured temperature TA measured by the temperature sensor 25 is compared with the above estimated increase side temperature TB1, and if the rate of temperature increase does not match, the estimated increase side temperature TB1. Is set as the maximum temperature of the inverter 20. That is, when the temperature increase rate of the measured temperature TA and the rising side estimated temperature TB1 does not match, it can be determined that the temperature of the switching elements other than the switching element Q14 provided with the temperature sensor 25 has increased, so that the switching element Is estimated from the estimated temperature TB1 on the rising side.

  Further, in the present embodiment, as shown in FIG. 5 (b), after the stall state of the motor 3 is detected, when the determination of the stall state is canceled, the measured temperature TA and the estimated increase temperature TB1 are The difference temperature dT is calculated, and after that, until the next stall state is determined, the difference temperature dT is a value obtained by decreasing the difference temperature dT with a constant rate of change (−α) with respect to the elapsed time t. The estimated temperature TB2 is set as the estimated temperature TB.

  According to this, since it is possible to calculate an appropriate temperature corresponding to the actual temperature of the inverter 20 (switching elements Q11 to Q16) as the estimated temperature TB after the determination of the stall state is cancelled, the switching element Q11 The temperature of .about.Q16 can be accurately predicted, and the inverter 20 can be effectively protected.

  Further, in the present embodiment, until the descending side estimated temperature TB2 becomes equal to or lower than the measured temperature TA, the descending side estimated temperature TB2 is set as the estimated temperature TB, and when the descending side estimated temperature TB2 becomes less than the measured temperature TA, the measurement is performed. The temperature TA is set to the estimated temperature TB. According to this, since the estimated temperature TB is calculated as a temperature closer to the actual temperature of the inverter 20 (switching elements Q11 to Q16), even if the motor 3 stalls again, the temperature of the inverter 20 rises. Can be detected more safely, and the effectiveness of protection control of the inverter 20 can be further enhanced.

  Further, in the present embodiment, in the calculation of the estimated temperature TB after the next stall state is determined, the estimated temperature TB is replaced by the measured temperature TA measured by the temperature sensor 25 with the descending estimated temperature TB2 at the time when the stall state is determined. TB is calculated.

  If the stall state determination is canceled in a state where the temperature of the inverter 20 has risen, then the above-described lower side estimated temperature TB2 will be used as the estimated temperature TB. In this case, the motor 3 will stall again. When, for example, current concentration occurs in the same phase of the switching element as in the previous stall, it is between the estimated temperature TB based on the measured temperature TA of the temperature sensor 25 and the maximum temperature (actual temperature TC) of the actual inverter. An error may occur. Therefore, in order to prevent the error from occurring, when the determination of the stalled state is canceled while the temperature of the inverter 20 is increased, the temperature measured by the temperature sensor 25 is decreased when the stalled state is determined. The estimated temperature TB after that is calculated by substituting with the estimated side temperature TB2. Thereby, the precision of estimated temperature TB to calculate (rising side estimated temperature TB1) can be raised.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims and the specification and drawings. Deformation is possible. For example, although the case where only one temperature sensor 25 that measures the temperature of one switching element Q14 included in the inverter 20 is provided in the above embodiment, a plurality of temperature sensors according to the present invention are provided. It may be provided in two or more of the switching elements. In this case, if the measured temperature of one temperature sensor is constant when the stall state of the motor 3 is determined, the measured temperature of the other temperature sensor is compared with the estimated temperature to determine the maximum temperature of the inverter 20. Good.

  That is, when the temperature sensor is provided in two or more of the plurality of switching elements, if the temperature of the switching element provided with one temperature sensor does not increase, the temperature of the switching element provided with another temperature sensor. Is used as the measurement temperature TA of this embodiment. Thereby, it becomes possible to detect the temperature of a plurality of switching elements with higher accuracy.

  In the above embodiment, as the inverter protection control performed at the stall determination, first, the operation of the brake 37 (coordinate control of the brake 37 with respect to the motor 3) for braking the drive wheels WR and WL of the vehicle 1 is started, and thereafter In addition to the above, the control for limiting the output torque of the motor 3 has been shown. In addition to this, as the inverter protection control, the brake cooperative control is not performed, and only the control for limiting the output torque of the motor 3 is performed. Also good. In that case, when the motor 3 is reversely rotated, the vehicle 1 moves backward. However, since the reduction ratio (here, “the number of rotations of the motor 3 / the number of rotations of the wheels”) is large, The amount of actual rearward movement is very small, so that the driver cannot feel that the vehicle 1 is moving backward. That is, it is substantially equivalent to holding (stopping) at that place.

  Further, when the motor 3 is stalled while the vehicle 1 is traveling uphill, only the control for limiting the output torque of the motor 3 without performing the brake cooperative control as described above is performed as the inverter protection control. Then, when the vehicle 1 moves rearward (downhill) by its own weight (sliding down), the rotor (not shown) of the motor 3 rotates and the energized phase is switched. Thereafter, if the accelerator opening is increased by the driver depressing the accelerator pedal, the driving force of the motor 3 increases again. At that time, the energized phase of the motor 3 has already been switched. The vehicle 1 can travel.

1 Vehicle 2 Engine 3 Motor (electric motor)
4 Transmission 5 Differential mechanism 10 Electronic control unit (ECU)
20 Inverter (motor control means)
25 Temperature sensor 27 Detection circuit 30 Battery 31 Accelerator pedal sensor 32 Brake pedal sensor 33 Shift position sensor 34 Rotation speed sensor 35 Inclination angle sensor 37 Brake TA Measurement temperature TB Estimated temperature TB1 Increased estimated temperature TB2 Reduced estimated temperature TC Actual temperature TH Maximum temperature TP Inverter protection threshold temperature V Vehicle speed dT1 Differential temperature

Claims (11)

A vehicle drive motor control device comprising: a three-phase AC motor as a vehicle drive source; an inverter having a plurality of switching elements for controlling the three-phase AC motor; and a control means for controlling the inverter. ,
A temperature sensor in which a number smaller than the number of the plurality of switching elements is installed;
A stall state determination means for determining a stall state of the electric motor;
Temperature estimation means for calculating an estimated temperature obtained by estimating the temperature of the switching element having the highest temperature among the plurality of switching elements based on the measured temperature measured by the temperature sensor;
When the stall state determination unit determines the stall state of the electric motor, the control unit calculates a temperature of either the measured temperature measured by the temperature sensor or the estimated temperature estimated by the temperature estimation unit. A control device for an electric motor for driving a vehicle, characterized in that it is set as a maximum temperature, and a predetermined protection control is performed for the inverter when the maximum temperature becomes a predetermined threshold value or more. 2. The vehicle drive motor control device according to claim 1, wherein the inverter protection control by the control means is a motor torque limit for limiting an output torque of the motor. 3. The temperature estimation means has data of a plurality of temperature change rates having different rates of increase for each required torque of the electric motor prepared in advance, and any one of the temperature changes selected according to the required torque of the electric motor Calculate the estimated temperature on the rising side based on the rate data,
The control means compares the measured temperature with the estimated temperature on the rising side when the stall condition determining means determines the stall condition of the electric motor. The vehicle drive motor control device according to claim 1, wherein a side estimated temperature is set as a maximum temperature of the inverter. The temperature sensor is provided in two or more of the plurality of switching elements,
If the measured temperature of one temperature sensor is constant when the stalled state determining unit determines the stalled state of the electric motor, the control unit is either the measured temperature of the other temperature sensor or the estimated temperature. Is set as the maximum temperature of the inverter, the control device for the motor for driving a vehicle according to claim 1. A vehicle drive motor control device comprising: a three-phase AC motor as a vehicle drive source; an inverter having a plurality of switching elements for controlling the three-phase AC motor; and a control means for controlling the inverter. ,
A temperature sensor provided in only one of the plurality of switching elements;
A stall state determination means for determining a stall state of the electric motor;
Temperature estimation means for calculating an estimated temperature obtained by estimating the temperature of the switching element having the highest temperature among the plurality of switching elements based on the measured temperature measured by the temperature sensor;
The stall state determining means determines that the motor is in a stalled state when the output torque of the motor is present and the rotation of the motor is substantially stopped and the energized phase does not change,
When the stall state determination unit determines the stall state of the motor, the control unit sets the temperature of the temperature sensor and the estimated temperature of the temperature estimation unit as the highest temperature of the inverter, When the maximum temperature is equal to or higher than a predetermined threshold value, a motor drive motor control device that performs motor torque limitation that limits output torque of the motor as protection control for the inverter. The temperature estimation means has a plurality of current concentration phase temperature change models having different rates of increase for each required torque of the electric motor, and any one of the temperature change models selected according to the required torque of the electric motor Calculate the rising side estimated temperature based on
The control means compares the measured temperature with the estimated increase side temperature when the stall condition determination means determines the stall condition of the electric motor. 6. The vehicle drive motor control device according to claim 5, wherein the estimated temperature is set as a maximum temperature of the inverter. A brake for braking the drive wheels of the vehicle;
6. The vehicle drive system according to claim 2, wherein the control unit starts braking of the driving wheel by operating the brake before limiting the output torque of the electric motor as the inverter protection control. 6. Electric motor control device. An internal combustion engine as a drive source of the vehicle;
A power transmission path for transmitting power between the electric motor and the internal combustion engine,
When the vehicle travels only with the driving force of the electric motor,
6. The motor for driving a vehicle according to claim 2 or 5, wherein when the output torque of the motor is limited as the inverter protection control, the internal combustion engine is started by the current machine via the power transmission path. Control device. After the stall state determination means determines the stall state of the electric motor, when the determination of the stall state is canceled, the difference temperature between the measured temperature and the rising side estimated temperature is calculated,
After the difference temperature is calculated, until the next stall state is determined, a lower side estimated temperature that is a value obtained by lowering the difference temperature with a constant change rate with respect to the elapsed time is set as the estimated temperature. The vehicle drive motor control device according to claim 3 or 6. Until the lower side estimated temperature becomes equal to or lower than the measured temperature, the lower side estimated temperature is set as the estimated temperature,
The control device for a motor for driving a vehicle according to claim 9, wherein when the descending estimated temperature becomes lower than the measured temperature, the measured temperature is set as the estimated temperature. In the calculation of the estimated temperature after the next stall condition is determined, the estimated temperature is calculated by substituting the temperature measured by the temperature sensor with the estimated temperature at the lower side when the stall condition is determined. The vehicle drive motor control device according to claim 9.

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