Motor control device

Abstract

Disclosed is a motor control device. The motor control device (10) is provided with an atmospheric pressure sensor (11), a coil temperature sensor (12), and a voltage sensor (13) that detects a voltage applied to a motor (6), a partial discharge start voltage is calculated based on the atmospheric pressure and the coil temperature, in the case where the coil temperature exceeds a set coil temperature upper limit value, the output of the motor (6) is limited, and in the case where the voltage exceeds the partial discharge start voltage, the coil temperature upper limit value is set low.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Japanese Patent Application No. 2020-214720, filed on December 24, 2020, and Japanese Patent Application No. 2021-112796, filed on July 7, 2021, which are incorporated herein by reference, including the description, claims, drawings and abstract. Technical Field

[0003] This disclosure relates to a motor control device for controlling the insulating coating that protects the coils of a motor. Background Technology

[0004] Motors are installed in, for example, electric vehicles. In these motors, when the applied voltage exceeds a predetermined voltage (partial discharge initiation voltage), partial discharge occurs in the insulating film of the coil, deteriorating the insulation performance of the film and reducing the motor's lifespan. The partial discharge initiation voltage depends on atmospheric pressure and coil temperature. Therefore, for example, when an electric vehicle is traveling at high altitudes, the partial discharge initiation voltage is lower than at low altitudes, making insulation performance more prone to degradation.

[0005] Japanese Patent Application Publication No. 2020-018067 discloses a motor control device that reduces the voltage applied to the motor via a boost converter when the voltage applied to the motor exceeds the partial discharge initiation voltage. This prevents degradation of the insulation performance of the motor's insulating film and avoids a reduction in the motor's lifespan. Summary of the Invention

[0006] However, electric vehicles sometimes lack a boost converter. Furthermore, boost converters and the boost circuitry that makes them up are expensive and have high component costs.

[0007] Therefore, the purpose of this disclosure is to provide a motor control device that can avoid the degradation of the insulation performance of the insulating film without the need for a boost converter, even when the voltage applied to the motor exceeds the partial discharge initiation voltage.

[0008] This disclosure provides a motor control device, characterized by comprising: an electronic control unit (ECU); an atmospheric pressure detection unit for detecting atmospheric pressure; a coil temperature detection unit for detecting the coil temperature of the motor; and a voltage detection unit for detecting the voltage applied to the motor. The ECU is configured to: calculate a partial discharge start voltage based on the atmospheric pressure detected by the atmospheric pressure detection unit and the coil temperature detected by the coil temperature detection unit; limit the output of the motor when the coil temperature detected by the coil temperature detection unit exceeds a set upper limit value for the coil temperature; and set the upper limit value for the coil temperature to a lower value when the voltage detected by the voltage detection unit exceeds the partial discharge start voltage.

[0009] The present disclosure provides a motor control device characterized by including: an electronic control unit (ECU); an atmospheric pressure detection unit that detects an atmospheric pressure; a plurality of coil temperature detection units that respectively detect coil temperatures of a plurality of motors; and a voltage detection unit that detects a voltage applied to the motors, the ECU being configured to calculate a plurality of partial discharge start voltages for each of the plurality of motors, respectively, based on the atmospheric pressure detected by the atmospheric pressure detection unit and the plurality of coil temperatures respectively detected by the plurality of coil temperature detection units, limit an output of a motor that exceeds a coil temperature upper limit value in a case where the plurality of coil temperatures respectively detected by the plurality of coil temperature detection units exceed the coil temperature upper limit value set for the coil, and set the coil temperature upper limit value of the motor that exceeds the partial discharge start voltage to be low in a case where the voltage detected by the voltage detection unit exceeds each of the plurality of partial discharge start voltages.

[0010] The present disclosure provides a motor control device characterized by including: an electronic control unit (ECU); an atmospheric pressure detection unit that detects an atmospheric pressure; a coil temperature detection unit that detects a coil temperature of a motor; and a voltage detection unit that detects a voltage applied to the motor, the ECU calculating a partial discharge start voltage based on the atmospheric pressure detected by the atmospheric pressure detection unit and the coil temperature detected by the coil temperature detection unit, and setting an upper limit charge rate of a battery that supplies electric power to the motor to be low in a case where the voltage detected by the voltage detection unit exceeds the partial discharge start voltage.

[0011] According to the motor control device of the present disclosure, even in a case where the voltage applied to the motor exceeds the partial discharge start voltage, the partial discharge start voltage is increased by suppressing an increase in the coil temperature, so that it is possible to avoid deterioration of the insulation performance of the insulation coating and reduction in the durability life of the motor without using a step-up converter.

[0012] In addition, according to the motor control device of the present disclosure, even in a case where the motor control device is provided in a vehicle having a plurality of motors, the partial discharge start voltage is increased by suppressing an increase in the coil temperature only for a motor for which the voltage applied to the motor exceeds the partial discharge start voltage, so that it is possible to avoid deterioration of the insulation performance of the insulation coating and reduction in the durability life of the motor. In other words, it is possible to avoid an excessive reduction in the output of the vehicle without limiting an output of a motor for which the voltage applied to the motor does not exceed the partial discharge start voltage.

[0013] According to the motor control device of the present disclosure, even in a case where the voltage applied to the motor exceeds the partial discharge start voltage, the voltage applied to the motor is made to be equal to or lower than a predetermined voltage by setting the upper limit charge rate of the battery to be low, so that it is possible to avoid deterioration of the insulation performance of the insulation coating and reduction in the durability life of the motor without using a step-up converter. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a schematic view of a vehicle in which a motor control device as one example of an embodiment is provided.

[0015] Figure 2 is a block diagram showing the structure of the motor control device.

[0016] Figure 3 is a graph showing the correlation of the partial discharge start voltage of the motor and the atmospheric pressure at each coil temperature.

[0017] Figure 4 is a graph showing the correlation of the coil temperature and the output of the motor.

[0018] Figure 5 is an insulation breakdown curve of the coil of the motor, and is a graph showing the correlation of the applied voltage and the number of times of application of the voltage in each characteristic.

[0019] Figure 6 is a flowchart showing the flow of the insulation coating protection control.

[0020] Figure 7 is a schematic view of a vehicle in which a motor control device as another example of an embodiment is provided.

[0021] Figure 8 is a block diagram showing the structure of the motor control device.

[0022] Figure 9 is a schematic view of a vehicle in which a motor control device as another example of an embodiment is provided.

[0023] Figure 10 is a block diagram showing the structure of the motor control device.

[0024] Figure 11 is an insulation breakdown curve of the coil of the motor, and is a graph showing the correlation of the applied voltage and the number of times of application of the voltage in each characteristic.

[0025] Figure 12 is a flowchart showing the flow of the insulation coating protection control. DETAILED DESCRIPTION

[0026] Hereinafter, one example of an embodiment of the present disclosure will be described in detail. In the following description, specific shapes, materials, directions, numerical values, and the like are exemplifications for facilitating understanding of the present disclosure, and can be appropriately changed to match the use, purpose, specifications, and the like.

[0027] Use Figure 1 , a vehicle 5 in which a motor control device 10 as one example of an embodiment is provided is described.

[0028] AsFigure 1 As shown, a motor control unit 10 is provided in the vehicle 5, including an ECU (Electronic Control Unit) 51 that acts as a processor for various data processing. In this example, the vehicle 5 is an electric vehicle that drives a motor 6 powered by electricity supplied from a battery 7. Alternatively, the vehicle 5 could also be, for example, a hybrid vehicle.

[0029] The motor control device 10 is a control device that performs insulation film protection control on the insulation film protecting the coil of the motor 6 (described later). According to the motor control device 10, even when the voltage applied to the motor 6 exceeds the partial discharge initiation voltage, the partial discharge initiation voltage is increased by suppressing the rise in coil temperature, thereby preventing the insulation performance of the insulation film from deteriorating and the lifespan of the motor 6 from decreasing (details described later). Therefore, without using a boost converter, the insulation performance of the insulation film can be prevented from deteriorating, and the lifespan of the motor 6 can be prevented from decreasing.

[0030] The motor control device 10 includes: an atmospheric pressure sensor 11 for detecting atmospheric pressure; a coil temperature sensor 12 for detecting the coil temperature of the motor 6; and a voltage sensor 13 for detecting the voltage applied to the motor 6 (hereinafter referred to as applied voltage).

[0031] use Figures 2 to 5 This describes the structure of the motor control device 10.

[0032] The ECU51 has a CPU (Central Processing Unit) as an arithmetic processing unit and storage units such as RAM (Random Access Memory) and ROM (Read Only Memory). It utilizes the temporary storage function of RAM while performing signal processing according to the program pre-stored in ROM.

[0033] like Figure 2 As shown, ECU 51 is connected to atmospheric pressure sensor 11, coil temperature sensor 12, voltage sensor 13, etc., and receives signals from these sensors. Additionally, ECU 51 is connected to motor 6 and sends signals to it.

[0034] ECU51 includes: an atmospheric pressure acquisition unit 14, which acquires the atmospheric pressure detected by the atmospheric pressure sensor 11; a coil temperature acquisition unit 15, which acquires the coil temperature of the motor 6 detected by the coil temperature sensor 12; a partial discharge start voltage calculation unit 16 (hereinafter PDIV calculation unit 16), which calculates the partial discharge start voltage; a voltage acquisition unit 17, which acquires the applied voltage detected by the voltage sensor 13; a counting unit 18, which counts the number of times the voltage of the motor 6 exceeds the partial discharge start voltage; and a coil temperature upper limit value reduction unit 19, which sets the coil temperature upper limit value to a low value.

[0035] The PDIV calculation unit 16 has the function of calculating the partial discharge initiation voltage based on atmospheric pressure and the coil temperature of the motor 6, as described above. The partial discharge initiation voltage is the voltage at which partial discharge occurs in the insulating film of the coil when a voltage higher than this voltage is applied to the motor 6. When partial discharge occurs in the insulating film of the coil, the insulation performance of the insulating film deteriorates, and the service life of the motor 6 decreases. Figure 3 As shown, the partial discharge initiation voltage varies depending on atmospheric pressure and the coil temperature of motor 6.

[0036] The counting unit 18 has the function of counting the number of times the applied voltage exceeds the partial discharge start voltage, as described above. Furthermore, the counting unit 18 can also calculate the total time for which the applied voltage exceeds the partial discharge start voltage.

[0037] The coil temperature upper limit reduction unit 19 has the function of setting the coil temperature upper limit lower when the number of times the applied voltage exceeds the partial discharge start voltage exceeds a predetermined number. When the coil temperature rises, it damages the coil coating, causing short circuits and overheating in the motor 6. Therefore, the coil temperature upper limit refers to the preset allowable upper limit value of the coil temperature.

[0038] like Figure 4 As shown, the correlation between coil temperature and motor 6 output is set such that when the coil temperature is below a predetermined temperature, the upper limit of motor 6 output remains constant, and when the coil temperature is above the predetermined temperature, the upper limit of motor 6 output is reduced. In other words, the coil temperature upper limit reduction unit 29 sets a low predetermined temperature at which the reduction of motor 6 output upper limit begins.

[0039] When the output of motor 6 exceeds the upper limit of the output, the output of motor 6 is preferably limited, for example, by limiting the torque of motor 6 or limiting the current of the power supplied to motor 6.

[0040] exist Figure 5In the insulation breakdown curve of the coil of the motor 6, the relationship between the applied voltage and the number of times of the applied voltage is shown. The insulation breakdown curve is a curve showing the relationship between the applied voltage and the number of times of the applied voltage which is a limit of the insulation coating breakdown of the coil of the motor 6. In the case where the coil temperature upper limit value is set low by the coil temperature upper limit value lowering section 19, the partial discharge start voltage rises, so the insulation breakdown curve is moderated (rises in the graph in Figure 5

[0041] According to the coil temperature upper limit value lowering section 19, the coil temperature at which the output upper limit value is lowered is set low, and the rise in the coil temperature is suppressed to cause the partial discharge start voltage to rise. Thereby, even in the case where the applied voltage exceeds the partial discharge start voltage before the rise, the insulation performance of the insulation coating can be prevented from deteriorating, and the durability life of the motor 6 can be prevented from decreasing. As a result, without using a step-up converter, the insulation performance of the insulation coating can be prevented from deteriorating, and the durability life of the motor 6 can be prevented from decreasing.

[0042] Using Figure 6 , the flow of the insulation coating protection control by the motor control device 10 will be described.

[0043] As shown in Figure 6 , in step Sll, the atmospheric pressure detected by the atmospheric pressure sensor 11 is acquired by the atmospheric pressure acquisition section 14. In step S12, the coil temperature of the motor 6 acquired by the coil temperature sensor 12 is acquired by the coil temperature acquisition section 15.

[0044] In step S13, the partial discharge start voltage is calculated by the PDIV calculation section 16 based on the atmospheric pressure acquired in step Sll and the coil temperature acquired in step S12. The correlation of the atmospheric pressure, the coil temperature, and the partial discharge start voltage is stored in the motor control device 10 in advance.

[0045] In step S14, the voltage applied to the motor 6 detected by the voltage sensor 13 is acquired by the voltage acquisition section 17. In step S15, it is determined whether the voltage acquired in step S14 exceeds the partial discharge start voltage by a predetermined number of times. In the case where the predetermined number of times is exceeded, the process proceeds to step S16. In the case where the predetermined number of times is not exceeded, the process returns to step S14.

[0046] In step S16, the coil temperature upper limit value is set low by the coil temperature upper limit value lowering section 19. In other words, the coil temperature at which the lowering of the output upper limit value of the motor 6 is started is set low.

[0047] Using Figure 7 , the motor control device 20 as another example of the embodiment will be described.

[0048] As shown in Figure 7 ​As shown, the motor control device 20 is provided in the vehicle 5, including an ECU 52 (Electronic Control Unit) as a processor that performs various data processing. The vehicle 5 of the present example is an electric vehicle that is driven by the power supplied from the battery 7 and travels as a motive power using the motors 6. Further, the vehicle 5 can also be a hybrid vehicle, for example.

[0049] The motor control device 20 is a device that controls the plurality of motors 6 provided in the vehicle 5. According to the motor control device 20, the partial discharge start voltage is raised only for the motor 6 for which the voltage applied to the motor 6 exceeds the partial discharge start voltage, to suppress the rise in the coil temperature, so that the deterioration of the insulation performance of the insulation coating film can be avoided, and the reduction in the durability life of the motor 6 can be avoided, the details of which will be described later. In other words, the output of the motor 6 for which the voltage applied to the motor 6 does not exceed the partial discharge start voltage is not limited, and the output of the vehicle 5 can be prevented from being excessively reduced.

[0050] The motor control device 20 has an atmospheric pressure sensor 21 that detects the atmospheric pressure, a plurality of coil temperature sensors 22 that detect the coil temperature of each of the plurality of motors 6, and a voltage sensor 23 that detects the applied voltage.

[0051] The use Figure 8 of the motor control device 20 will be described.

[0052] The ECU 52 has a CPU (Central Processing Unit) as an arithmetic processing unit, and a RAM (Random Access Memory) and a ROM (Read Only Memory) as storage units, and performs signal processing in accordance with a program stored in the ROM while using the temporary storage function of the RAM.

[0053] The ECU 52 includes an atmospheric pressure acquisition unit 24 that acquires the atmospheric pressure detected by the atmospheric pressure sensor 21, a coil temperature acquisition unit 25 that acquires the coil temperature of the motor 6 detected by the coil temperature sensor 22, a partial discharge start voltage calculation unit 26 (hereinafter, PDIV calculation unit 26) that calculates the partial discharge start voltage, a voltage acquisition unit 27 that acquires the applied voltage of the motor 6 detected by the voltage sensor 23, a count unit 28 that counts the number of times the applied voltage exceeds the partial discharge start voltage, and a coil temperature upper limit value lowering unit 29 that sets the coil temperature upper limit value to be low.

[0054] The PDIV calculation unit 26 calculates a plurality of partial discharge start voltages for each of the plurality of motors 6, based on the atmospheric pressure acquired by the atmospheric pressure acquisition unit 24 and the plurality of coil temperatures detected by the coil temperature acquisition unit 25.

[0055] The coil temperature upper limit value lowering section 29 counts the number of times the voltage detected by the voltage acquisition section 27 exceeds the partial discharge start voltage, and sets the coil temperature upper limit value of the motor 6 to be low when the number of times exceeds a predetermined number of times.

[0056] The functions of the other motor control device 20 are the same as those of the above-described motor control device 10, and thus the description thereof is omitted.

[0057] Using Figure 9 , a vehicle 5 provided with a motor control device 30 as another example of the embodiment is described.

[0058] As shown in Figure 9 , the motor control device 30 is provided in the vehicle 5, and includes an ECU 53 (Electronic Control Unit) as a processor that performs various data processing. The vehicle 5 of the present example is an electric vehicle that drives the motor 6 by power supplied from a battery 7 and travels as a motive power using the motor 6. Further, the vehicle 5 can be, for example, a hybrid vehicle.

[0059] The motor control device 30 is a control device that performs the later-described insulation coating protection control for protecting the insulation coating of the coil of the motor 6. According to the motor control device 30, even in a case where the voltage applied to the motor 6 exceeds the partial discharge start voltage, the voltage applied to the motor 6 is made to be equal to or lower than a predetermined voltage by setting the upper limit charge rate of the battery 7 to be low, and thus it is possible to avoid deterioration of the insulation performance of the insulation coating and reduction in the durability life of the motor 6, the details of which are described later. Thus, it is possible to avoid deterioration of the insulation performance of the insulation coating and reduction in the durability life of the motor 6 without using a step-up converter.

[0060] The motor control device 30 has an atmospheric pressure sensor 31 that detects the atmospheric pressure, a coil temperature sensor 32 that detects the coil temperature of the motor 6, and a voltage sensor 33 that detects the voltage applied to the motor 6 (hereinafter, the applied voltage).

[0061] Using Figure 10 and Figure 11 , the structure of the motor control device 30 is described.

[0062] The ECU 53 has a CPU (Central Processing Unit) as an arithmetic processing section and a RAM (Random Access Memory) and a ROM (Read Only Memory) and the like as a storage section, and performs signal processing in accordance with a program stored in advance in the ROM while using the temporary storage function of the RAM.

[0063] As shown in FIG. 1, the ECU 53 is connected to the atmospheric pressure sensor 31, the coil temperature sensor 32, the voltage sensor 33, and the like, and receives signals transmitted from these. In addition, the ECU 53 is connected to the motor 6, and transmits signals to the motor 6. Figure 10

[0064] The ECU 53 includes an atmospheric pressure acquisition section 34 that acquires the atmospheric pressure detected by the atmospheric pressure sensor 31, a coil temperature acquisition section 35 that acquires the coil temperature of the motor 6 detected by the coil temperature sensor 32, a partial discharge start voltage calculation section 36 (hereinafter, PDIV calculation section 36) that calculates the partial discharge start voltage, a voltage acquisition section 37 that acquires the applied voltage detected by the voltage sensor 33, a counting section 38 that counts the number of times that the voltage of the motor 6 exceeds the partial discharge start voltage, and a battery upper limit charge rate reduction section 39 that sets the upper limit charge rate of the battery 7 to be low.

[0065] The PDIV calculation section 36 calculates the partial discharge start voltage in accordance with the atmospheric pressure and the coil temperature of the motor 6 as described above.

[0066] The counting section 38 counts the number of times that the applied voltage exceeds the partial discharge start voltage as described above. In addition, the counting section 38 can also calculate the total time of the time that the applied voltage exceeds the partial discharge start voltage.

[0067] The battery upper limit charge rate reduction section 39 sets the upper limit charge rate of the battery 7 to be low in a case where the number of times that the applied voltage exceeds the partial discharge start voltage becomes a predetermined number of times or more. The upper limit charge rate of the battery 7 is the upper limit rate of the proportion of the remaining amount after the discharged amount is removed from the state where the battery 7 is fully charged.

[0068] Specifically, the battery upper limit charge rate reduction section 39 sets the upper limit charge rate of the battery 7 to be low, so that if, for example, the vehicle 5 is running, the charging of the battery 7 by the regenerative energy is limited to be a predetermined charge rate or less. In addition, the charging of the battery 7 is limited to be a predetermined charge rate or less by the charging device.

[0069] In the motor 6, the relationship between the applied voltage and the number of times of the applied voltage is shown in an insulation breakdown curve of the coil of the motor 6. The insulation breakdown curve is a curve showing the relationship between the applied voltage and the number of times of the applied voltage that is a limit of the breakdown of the insulation coating of the coil of the motor 6. In a case where the upper limit charge rate of the battery 7 is set to be low by the battery upper limit charge rate reduction section 39, the applied voltage to the motor 6 becomes a predetermined voltage or less, so as to be away from the insulation breakdown curve. Figure 11

[0070] ​​According to the battery upper limit charging rate reduction section 39, by setting the upper limit charging rate of the battery 7 to be low, the voltage applied to the motor 6 becomes lower than the predetermined voltage, so that without using a step-up converter, it is possible to avoid deterioration of the insulation performance of the insulation coating and to avoid reduction of the durability life of the motor 6.

[0071] Using Figure 12 , the flow of the insulation coating protection control performed by the motor control device 30 is explained.

[0072] As Figure 12 shown, in step S31, the atmospheric pressure detected by the atmospheric pressure sensor 31 is acquired by the atmospheric pressure acquisition section 34. In step S32, the coil temperature of the motor 6 acquired by the coil temperature sensor 32 is acquired by the coil temperature acquisition section 35.

[0073] In step S33, the partial discharge start voltage is calculated by the PDIV calculation section 36 based on the atmospheric pressure acquired in step S31 and the coil temperature acquired in step S32. The correlation of the atmospheric pressure, the coil temperature, and the partial discharge start voltage is stored in the motor control device 30 in advance.

[0074] In step S34, the voltage applied to the motor 6 detected by the voltage sensor 33 is acquired by the voltage acquisition section 37. In step S35, it is determined whether the voltage acquired in step S34 exceeds the partial discharge start voltage by a predetermined number of times. In the case where it exceeds the predetermined number of times, the processing proceeds to step S36. In the case where it does not exceed the predetermined number of times, the processing returns to step S34.

[0075] In step S36, the upper limit charging rate of the battery 7 is set to be low by the battery upper limit charging rate reduction section 39. In other words, the voltage applied to the motor 6 is set to be lower than the predetermined voltage.

[0076] Furthermore, the present disclosure is not limited to the above-described embodiments and modified examples thereof, and various changes and improvements can of course be made within the scope of the matters recited in the claims of the present application.

Claims

1. A motor control device, comprising: an electronic control unit (ECU); an atmospheric pressure detection section that detects atmospheric pressure; a coil temperature detection section that detects a coil temperature of a motor; and a voltage detection section that detects a voltage applied to the motor, the ECU being configured to: calculate a partial discharge start voltage based on the atmospheric pressure detected by the atmospheric pressure detection section and the coil temperature detected by the coil temperature detection section, reduce an output upper limit value of the motor in a case where the coil temperature detected by the coil temperature detection section exceeds a set coil temperature upper limit value, and cause the partial discharge start voltage to rise by setting the coil temperature upper limit value to be low in a case where the voltage detected by the voltage detection section exceeds the partial discharge start voltage.

2. A motor control device, comprising: an electronic control unit (ECU); an atmospheric pressure detection section that detects atmospheric pressure; a plurality of coil temperature detection sections that respectively detect coil temperatures of a plurality of motors; and a voltage detection section that detects a voltage applied to the motors, the ECU being configured to: calculate a plurality of partial discharge start voltages for each of the plurality of motors based on the atmospheric pressure detected by the atmospheric pressure detection section and the plurality of coil temperatures respectively detected by the plurality of coil temperature detection sections, limit an output of the motor that exceeds a coil temperature upper limit value set for the coil in a case where the plurality of coil temperatures detected by the plurality of coil temperature detection sections respectively exceed the coil temperature upper limit value set for the coil, and cause the partial discharge start voltage to rise by setting the coil temperature upper limit value of the motor that exceeds the partial discharge start voltage to be low in a case where the voltage detected by the voltage detection section exceeds each of the plurality of partial discharge start voltages. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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