CN114424450A - Motor control device, electric vehicle, and motor control method - Google Patents
Motor control device, electric vehicle, and motor control method Download PDFInfo
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- CN114424450A CN114424450A CN202080066320.0A CN202080066320A CN114424450A CN 114424450 A CN114424450 A CN 114424450A CN 202080066320 A CN202080066320 A CN 202080066320A CN 114424450 A CN114424450 A CN 114424450A
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- 238000000034 method Methods 0.000 title claims description 21
- 239000003507 refrigerant Substances 0.000 claims abstract description 52
- 238000006243 chemical reaction Methods 0.000 claims abstract description 13
- 238000009413 insulation Methods 0.000 claims description 15
- 230000015556 catabolic process Effects 0.000 description 16
- 230000008569 process Effects 0.000 description 9
- 238000010586 diagram Methods 0.000 description 8
- 230000008859 change Effects 0.000 description 6
- 238000001816 cooling Methods 0.000 description 5
- 238000001514 detection method Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 230000007274 generation of a signal involved in cell-cell signaling Effects 0.000 description 3
- 230000001276 controlling effect Effects 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010292 electrical insulation Methods 0.000 description 1
- 230000005669 field effect Effects 0.000 description 1
- 239000012208 gear oil Substances 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 239000002480 mineral oil Substances 0.000 description 1
- 235000010446 mineral oil Nutrition 0.000 description 1
- 230000001172 regenerating effect Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P23/00—Arrangements or methods for the control of AC motors characterised by a control method other than vector control
- H02P23/0004—Control strategies in general, e.g. linear type, e.g. P, PI, PID, using robust control
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K9/00—Arrangements for cooling or ventilating
- H02K9/19—Arrangements for cooling or ventilating for machines with closed casing and closed-circuit cooling using a liquid cooling medium, e.g. oil
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
- H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
- H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P29/00—Arrangements for regulating or controlling electric motors, appropriate for both AC and DC motors
- H02P29/02—Providing protection against overload without automatic interruption of supply
- H02P29/032—Preventing damage to the motor, e.g. setting individual current limits for different drive conditions
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P29/00—Arrangements for regulating or controlling electric motors, appropriate for both AC and DC motors
- H02P29/60—Controlling or determining the temperature of the motor or of the drive
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Inverter Devices (AREA)
- Control Of Electric Motors In General (AREA)
- Control Of Motors That Do Not Use Commutators (AREA)
- Control Of Ac Motors In General (AREA)
Abstract
A control device for a motor (200) cooled by an insulating refrigerant (300) circulated by a pump (310) is provided with: a current command calculation unit (10) that calculates a current command based on a torque command for the motor, a direct-current voltage applied from a power supply to a power conversion circuit (100), and a rotor position of the motor; and a limiting unit that limits the maximum value of the voltage applied to the motor (200) on the basis of the calculated current command, the calculated direct-current voltage, and the flow rate and temperature of the insulating refrigerant.
Description
Technical Field
The present invention relates to a motor control device, an electric vehicle, and a motor control method.
Background
A motor cooled by an insulating refrigerant is desired to ensure insulation durability and to improve cooling performance by circulation of the refrigerant. Therefore, a technique of controlling the flow rate of the refrigerant based on the temperature of the insulating refrigerant has been proposed.
As a background art of the invention of the present application, the following patent document 1 is known. Patent document 1 describes an electric device in which, when the temperature of the insulating medium detected by the temperature detection means exceeds a predetermined value, the flow rate of the insulating medium circulating between the interior of the electric device and the cooling device is increased from a steady-state flow rate to a flow rate within a range not exceeding the upper limit flow rate of the non-discharge region corresponding to the temperature of the insulating medium detected by the temperature detection means. This can ensure both insulation durability and improvement in cooling performance, and can improve the maximum output of the electrical equipment.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open No. 2006-32651
Disclosure of Invention
Problems to be solved by the invention
In patent document 1, when the temperature of the insulating refrigerant changes abruptly, the control of the refrigerant flow rate is delayed. Thus, the insulation durability of the electric device is reduced, and the output may be reduced. Therefore, it is an object to secure insulation durability of the electrical equipment even when the temperature of the insulating refrigerant changes abruptly.
Means for solving the problems
A control device for an electric motor cooled by an insulating refrigerant circulated by a pump, comprising: a current command calculation unit that calculates a current command based on a torque command for the motor, a direct-current voltage applied from a power supply to a power conversion circuit, and a rotor position of the motor; and a limiting unit that limits a maximum value of a voltage applied to the motor based on the calculated current command, the calculated direct-current voltage, and the flow rate and temperature of the insulating refrigerant.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present invention, the motor can secure the insulation durability corresponding to the rapid temperature change.
Drawings
Fig. 1 is an overall configuration of a motor and a motor control device according to an embodiment of the present invention.
Fig. 2 is a control block diagram of a motor control device according to embodiment 1 of the present invention.
Fig. 3 is a flowchart of a process of a limiting unit provided in the motor control device according to embodiment 1 of the present invention.
Fig. 4 shows a voltage waveform pattern applied to the motor at the time of switching according to embodiment 1 of the present invention.
Fig. 5 is a flowchart of a process of a limiting unit provided in a motor control device according to embodiment 2 of the present invention.
Fig. 6 is a flowchart of a process of a limiting unit provided in a motor control device according to embodiment 3 of the present invention.
Fig. 7 is a reference diagram of a waveform of a gate voltage applied to the switching element according to embodiment 3 of the present invention.
Fig. 8 is a diagram showing an electric vehicle to which a motor control device according to the present invention is applied.
Detailed Description
(Structure of Motor control device and 1 st embodiment)
Fig. 1 is a diagram showing an overall configuration of a control device associated with a motor and inverter control device 2 (hereinafter simply referred to as a control device 2) according to an embodiment of the present invention.
As shown in fig. 1, the overall configuration of the motor and the motor control device includes: the electric system control device 1 (hereinafter simply referred to as the control device 1), the control device 2, the pump control device 3 (hereinafter simply referred to as the control device 3), the inverter 100, the motor 200, the position sensor 210, the current sensor 220, the voltage sensor 230, the insulating refrigerant 300, the pump 310, the refrigerant flow sensor 320, and the refrigerant temperature sensor 330.
The control device 1 outputs a torque command to the motor 200 based on a command input from a higher-level control device not shown. The torque command is input to the control device 2.
The control device 2 PWM-controls the inverter 100 with a switching signal based on a torque command input from the control device 1, a three-phase alternating current detected by the current sensor 220, a rotor position of the motor 200 detected by the position sensor 210, and an input voltage detected by the voltage sensor 230. The details of the inside of the control device 2 will be described later.
The control device 3 outputs a refrigerant flow rate command for controlling the flow rate of the insulating refrigerant 300 to the pump 310 so that the motor 200 does not fail due to excessive temperature, based on the refrigerant flow rate input from the refrigerant flow rate sensor 320 and the refrigerant temperature input from the refrigerant temperature sensor 330.
The inverter 100 as a power conversion circuit is composed of switching elements 110a to 110 f. Switching element 110a is disposed in the U-phase upper arm, switching element 110b is disposed in the U-phase lower arm, switching element 110c is disposed in the V-phase upper arm, switching element 110d is disposed in the V-phase lower arm, switching element 110e is disposed in the W-phase upper arm, and switching element 110f is disposed in the W-phase lower arm.
The switching elements 110a to 110f are formed by combining a diode with a metal oxide film type field effect transistor (MOSFET), an Insulated Gate Bipolar Transistor (IGBT), or the like.
The switching elements 110a to 110f are turned on or off based on a switching signal generated by the control device 2. Thus, the switching elements 110a to 110f convert a dc voltage applied from an external dc power supply into an ac voltage. Here, the converted ac voltage is applied to the stator of the motor 200, and the three-phase coils provided in the stator generate ac currents, respectively. The three-phase alternating current causes the motor 200 to generate a rotating magnetic field, thereby rotating the rotor of the motor 200. The temperature of the switching elements 110a to 110f is detected by a detection unit, not shown, and fed back to the control device 2.
The position sensor 210 detects the position of the rotor of the motor 200. The rotor position detected here is output to the control device 2.
The current sensor 220 detects a three-phase alternating current flowing through the motor 200. The three-phase alternating current detected here is output to the control device 2.
The voltage sensor 230 detects a dc voltage (hereinafter, simply referred to as an input voltage) applied to the inverter 100 from an external dc power supply such as a battery, and outputs the detected input voltage to the control device 2.
The insulating refrigerant 300 is filled in the motor 200 and circulated by the pump 310. The insulating coolant 300 circulates between the motor 200 and the pump 310 by a cooling structure, not shown, thereby cooling the motor 200. The insulating refrigerant 300 is a liquid having electrical insulation properties such as mineral oil or gear oil for a transformer.
The pump 310 circulates the insulating refrigerant 300 and controls the flow rate based on a refrigerant flow rate command input from the pump control device 3.
The refrigerant flow sensor 320 detects the flow rate of the insulating refrigerant 300. The detected refrigerant flow rates are input to the control device 2 and the control device 3.
The refrigerant temperature sensor 330 detects the temperature of the insulating refrigerant 300. The detected refrigerant temperature is input to the control device 2 and the control device 3.
Fig. 2 is a control block diagram of a motor control device according to embodiment 1 of the present invention.
The current command calculation unit 10 (hereinafter, simply referred to as the calculation unit 10), the limiting unit 20, the current control unit 30, the PWM signal generation unit 40, and the speed conversion unit 50 in the block diagram of fig. 2 are provided inside the control device 2 as the main structure of the present invention.
The calculation unit 10 calculates a pre-limit current command based on the torque command input from the control device 1, the angular velocity and the rotor position fed back from the motor 200 via the speed conversion unit 50, the switching element temperature fed back from the inverter 100, and the input voltage detected by the voltage sensor 230.
For the calculation of the current command before limitation, which is output from the calculation unit 10 to the limitation unit 20, a known calculation technique such as maximum torque current control for the purpose of minimizing the output current, maximum efficiency control for the purpose of minimizing the power loss, or the like is used.
In order to prevent the switching elements 110a to 110f of the inverter 100 from being damaged due to excessive temperature, the pre-limit current command is controlled based on the switching element temperature. However, the pre-limit current command may be calculated without considering the influence of the switching element temperature depending on the use conditions of inverter 100 and the like. In this case, it is not necessary to feed back the switching element temperature from the inverter 100 to the arithmetic unit 10.
The limiting unit 20 calculates the post-limiting current command based on the pre-limiting current command input from the operation unit 10, the refrigerant flow rates and the refrigerant temperatures fed back from the sensors 320 and 330, respectively, and the input voltage fed back from the voltage sensor 230. The processing procedure inside the regulating unit 20 will be described with reference to fig. 3 described later.
The current control unit 30 outputs a voltage command to the PWM signal generation unit 40 by a known technique such as proportional control or integral control based on a predetermined control gain based on the post-limitation current command input from the limitation unit 20 and the three-phase ac current fed back from the current sensor 220.
The PWM signal generation unit 40 generates switching signals for turning on and off the switching elements 110a to 110f based on the input voltage command. For generating the switching signal, a triangular wave carrier comparison method, a space vector modulation method, or the like, which is a well-known technique, is used.
The data of the rotor position of the motor 200 detected by the position sensor 210 is fed back to the speed converter 50. The speed conversion unit 50 outputs the angular speed to the current command calculation unit 10 based on the data of the rotor position of the motor 200.
Fig. 3 is a flowchart of the processing of the limiting unit 20.
In step S1, the dielectric strength pressure is calculated based on the temperature and the flow rate of the insulating refrigerant 300. The withstand voltage of the motor 200 varies depending on the temperature and flow rate of the insulating refrigerant 300. However, since the influence of the flow electrification phenomenon is received, it is necessary to measure the leakage current in order to evaluate the influence. The leakage current varies depending on the temperature and flow rate of the insulating refrigerant 300, similarly to the dielectric breakdown voltage. Therefore, the limiting unit 20 stores therein the data of the relationship between the withstand voltage and the leakage current, which is different depending on the temperature and the flow rate of the insulating refrigerant 300, and calculates the correct withstand voltage according to the situation based on the data.
In step S2, the maximum value of the voltage applied to the motor 200 is calculated. The maximum value of the voltage is generated when the switching elements 110a to 110f are turned on or off. The magnitude of this voltage is related to the magnitude of the current at the time of switching on or off, i.e., the three-phase alternating current. In addition, the amplitude of the voltage applied to the motor 200 changes with the change in the input voltage. Therefore, for example, it is necessary to store in advance a condition that the voltage applied to the motor 200 becomes maximum, that is, a relationship between the three-phase alternating current and the maximum value of the voltage when the input voltage becomes maximum. Therefore, the data on the relationship between the three-phase ac current and the instantaneous maximum voltage, which are different depending on the input voltage, are stored in the limiting unit 20 in advance, and the maximum value of the voltage, which is accurate depending on the situation, is calculated based on the data and the pre-limiting current command input from the operation unit 10.
In step S3, the dielectric breakdown voltage calculated in step S1 and the maximum value of the voltage calculated in step S2 are compared, and it is determined whether or not the maximum value of the voltage is smaller than the dielectric breakdown voltage. At this time, in view of the fact that the maximum value of the voltage calculated in step S1 and the maximum value of the voltage calculated in step S2 each include an error, it is preferable to determine whether or not the sum of the maximum value of the voltage and the withstand voltage margin is smaller than the withstand voltage.
The dielectric breakdown voltage margin is a value additionally set to the calculated dielectric breakdown voltage so that the maximum value of the voltage does not exceed the dielectric breakdown voltage. Specifically, the withstand voltage margin is set when, for example, a calculation error of the withstand voltage due to a detection error of the temperature and the flow rate of the insulating refrigerant 300, a decrease in the withstand voltage due to the aged deterioration of the insulating refrigerant 300, an increase and decrease in the maximum value of the voltage due to a fluctuation in the input voltage, an increase and decrease in the maximum value of the voltage due to a change in the temperature of the switching element, and the like are compositely generated. If there are many variations that are not considered when calculating the maximum values of the withstand voltage and the calculation error is large, it is necessary to set the value of the withstand voltage margin to be larger.
In step S3, when it is determined that the maximum value of the voltage is smaller than the withstand voltage, the pre-limit current command is output without limitation, and the flowchart is ended. On the other hand, if it is determined that the maximum value of the voltage is equal to or higher than the dielectric breakdown voltage, the process proceeds to step S4.
In step S4, of the relationship data between the three-phase alternating current and the maximum voltage used when the maximum value of the voltage is calculated in step S2, a value of the three-phase alternating current at which the maximum value of the voltage becomes smaller than the dielectric breakdown voltage calculated in step S1 is calculated as the post-limiting output current. Then, the calculated post-limitation current command is output to the current control unit 30, and the flowchart is ended. Thereby, the three-phase ac current output from inverter 100 to motor 200 is limited, and the maximum value of the voltage applied from inverter 100 to motor 200 is limited. In this case, the sum of the maximum value of the voltage and the withstand voltage margin is preferably smaller than the withstand voltage in accordance with the error.
Fig. 4 is an example of the voltage waveform pattern applied to the motor at the time of switching of steps S3, S4 in fig. 3.
For example, in case 4 where the input voltage is high and the three-phase ac current is also large, the maximum value of the voltage applied to the motor 200 at the time of switching may exceed the dielectric breakdown voltage. In step S3 of limiting unit 20, control device 2 determines that the state is such that the maximum value of the voltage is equal to or greater than the dielectric breakdown voltage. As a result, the process proceeds to step S4 of the limiter 20. In step S4, the post-limitation current command is calculated, and the maximum value of the voltage is limited to be smaller than the withstand voltage as shown in case 3 of fig. 4.
On the other hand, if the three-phase ac current is limited even when the input voltage is low and the three-phase ac current is also low, the maximum value of the voltage applied to the motor 200 at the time of switching is excessively limited as in example 1, and the output of the inverter 100 is reduced more than necessary. Therefore, in step S2 of fig. 3, the maximum value of the voltage suitable for the situation is calculated and associated based on the relationship between the three-phase alternating current and the maximum value of the voltage stored for each input voltage.
According to embodiment 1 of the present invention described above, the following operational effects are exhibited.
(1) The control device 2 of the motor 200 cooled by the insulating refrigerant 300 circulated by the pump 310 includes: a current command calculation unit 10 that calculates a current command based on a torque command for the motor 200, a dc voltage applied from a power supply to the inverter 100, and a rotor position of the motor 200; and a limiting unit 20 that limits the maximum value of the voltage applied to the motor 200 based on the calculated current command, the dc voltage, and the flow rate and temperature of the insulating refrigerant 300. In this way, the motor 200 can secure an insulation resistance corresponding to a rapid change in temperature.
(2) The limiting unit 20 limits the maximum value of the voltage applied to the motor 200 by limiting the three-phase ac current output from the inverter 100 to the motor 200. In this way, in the control of the three-phase ac current by the control device 2, the maximum value of the voltage applied to the motor 200 can be limited.
(3) The limiter 20 calculates the dielectric strength of the motor 200 based on the flow rate and temperature of the insulating refrigerant 300 (step S1), and limits the maximum value of the voltage applied to the motor 200 based on the calculated dielectric strength (steps S2 to S4). In this way, the maximum value of the voltage applied to the motor 200 can be appropriately limited by the dielectric breakdown voltage.
(4) The limiter 20 calculates the maximum value of the voltage applied to the motor 200 from the current command and the dc voltage (step S2), and limits the maximum value of the voltage applied to the motor 200 so that the calculated maximum value of the voltage becomes smaller than the withstand voltage (steps S3 and S4). In this way, the maximum value of the voltage can be reliably kept at or below the withstand voltage, and the withstand voltage of the motor 200 can be ensured.
(embodiment 2)
Fig. 5 is a flowchart of the process of limiting unit 20 for limiting the maximum value of the voltage based on the switching element temperature of inverter 100 according to embodiment 2 of the present invention.
The maximum value of the voltage applied to the motor 200 is generated when the switching elements 110a to 110f are turned on or off, and the magnitude of the voltage is related to the temperature of the switching elements at the time of turning on or off.
In step S1, the insulation withstand voltage is calculated based on the temperature and the flow rate of the insulating refrigerant 300, as in step S1 of fig. 3.
In the present embodiment, the data on the relationship between the three-phase ac current and the maximum value of the voltage applied from the inverter 100 to the motor 200 is stored in advance in the limiting unit 20 for each switching element temperature. In step S2, data corresponding to the switching element temperature fed back from the inverter 100 to the limiting unit 20 is selected from the data of the relationship between the three-phase alternating current and the maximum value of the voltage, which is stored in advance for each switching element temperature. Based on the data thus selected, a more accurate maximum value of the voltage can be calculated from the input voltage fed back and the pre-limiting current command input from the arithmetic unit 10.
In step S3, as in step S3 of fig. 3, when it is determined that the maximum value of the voltage is smaller than the withstand voltage, the pre-limit current command is output without limitation, and the flowchart ends. On the other hand, if it is determined that the maximum value of the voltage is equal to or higher than the dielectric breakdown voltage, the process proceeds to step S4.
In step S4, as in step S4 of fig. 3, the value of the three-phase alternating current whose maximum voltage value is smaller than the dielectric breakdown voltage calculated in step S1 is calculated as the limited output current from the relationship between the three-phase alternating current selected in step S2 and the maximum voltage value. Then, the calculated post-limitation current command is output to the current control unit 30, and the flowchart is ended. In this case, the sum of the maximum value of the voltage and the withstand voltage margin is preferably smaller than the withstand voltage in accordance with the error.
According to embodiment 2 of the present invention described above, the following operational advantages are achieved.
(5) The limiting unit 20 calculates the maximum value of the voltage applied to the motor 200 based on the current command, the dc voltage, and the temperatures of the switching elements 110a to 110f of the inverter 100 (step S2). In this way, the maximum value of the voltage can be calculated from information other than the input voltage, and the motor 200 can secure the insulation resistance corresponding to the rapid temperature change. In addition, this can reduce the withstand voltage margin and suppress excessive limitation of the output three-phase ac current.
(embodiment 3)
Fig. 6 is a flowchart of the process of the limiting unit 20 for limiting the maximum value of the voltage based on the gate voltage according to embodiment 3 of the present invention.
The maximum value of the voltage applied to the motor 200 is generated when the switching elements 110a to 110f are turned on or off, and the magnitude thereof is related to the amplitude of the gate voltage that is driven to turn the switching elements on or off.
In step S1, the insulation withstand voltage is calculated based on the temperature and the flow rate of the insulating refrigerant 300, as in step S1 of fig. 3 and 5.
In the present embodiment, the data on the relationship between the three-phase ac current and the maximum value of the voltage applied from the inverter 100 to the motor 200 is stored in advance for each gate voltage in the limiting unit 20. The gate voltage is controlled by a control unit, not shown, using a known technique so as not to be applied excessively. This changes the gate voltage of the switching elements 110a to 110f of the driving inverter 100. In step S2, data corresponding to the current gate voltage is selected from the data of the relationship between the three-phase alternating current and the maximum value of the voltage, which is stored in advance for each gate voltage. Based on the data thus selected, the maximum value of the voltage which is accurate in accordance with the situation is calculated based on the input voltage fed back and the pre-limiting current command input from the operation unit 10.
In step S3, as in step S3 of fig. 3 and 5, when it is determined that the maximum value of the voltage is smaller than the withstand voltage, the pre-limit current command is output without limitation, and the flowchart ends. On the other hand, if it is determined that the maximum value of the voltage is equal to or higher than the dielectric breakdown voltage, the process proceeds to step S4.
In step S4, the maximum value of the calculated voltage is smaller than the gate voltage such as the dielectric breakdown voltage. If the amplitude of the gate voltage is reduced, the rate at which the gate voltage rises or falls is reduced. As a result, the speed at which the switching elements 110a to 110f are turned on or off is reduced, and therefore, the maximum value of the voltage can be limited by reducing the amplitude of the gate voltage.
In step S5, the relationship corresponding to the gate voltage calculated in step S4 is selected from the relationships between the three-phase alternating current power and the maximum value of the voltage for each gate voltage stored in advance in limiter 20. Then, from the relationship between the selected three-phase alternating current and the maximum value of the voltage, a value of the three-phase alternating current at which the maximum value of the voltage becomes smaller than the withstand voltage calculated in step S1 is calculated as the limited output current. Then, the calculated post-limitation current command is output to the current control unit 30, and the flowchart is ended.
Fig. 7 is a reference diagram of the waveform of the gate voltage applied to the switching element of embodiment 3.
If the gate voltage for turning on or off the switching elements 110a to 110f shown in fig. 7 is decreased from, for example, ± 15V at the time of application to ± 12V, the amplitude is decreased by 6V. If the amplitude of the gate voltage is reduced, the maximum value of the associated voltage is also reduced, and the dielectric breakdown tolerance is also reduced.
According to embodiment 3 of the present invention described above, the following operational effects are exhibited.
(6) The limiting unit 20 calculates the maximum value of the voltage applied to the motor 200 based on the current command, the dc voltage, and the gate voltage of the switching elements 110a to 110f that drive the inverter 100 (step S2). In this way, the maximum value of the voltage can be calculated from information other than the input voltage, and the motor 200 can secure the insulation resistance corresponding to the rapid temperature change. In addition, the withstand voltage margin can be reduced, and excessive limitation of the output three-phase ac current can be prevented.
(electric vehicle)
Fig. 8 is a diagram showing an electrically powered vehicle 600 to which the control device 2 of the present invention is applied. The electric vehicle 600 has a powertrain that uses the motor 200 as a motor/generator.
A front wheel axle 601 is rotatably supported at the front portion of the electric vehicle 600, and front wheels 602 and 603 are provided at both ends of the front wheel axle 601. A rear wheel axle 604 is rotatably supported at the rear of the electric vehicle 600, and rear wheels 605 and 606 are provided at both ends of the rear wheel axle 604.
A differential gear 611 serving as a power distribution mechanism is provided at the center of the front wheel axle 601, and distributes the rotational driving force transmitted from the engine 610 through the transmission 612 to the right and left front wheel axles 601. The engine 610 and the motor 200 are mechanically coupled via a belt that is stretched between a pulley provided on a crankshaft of the engine 610 and a pulley provided on a rotating shaft of the motor 200.
This allows the rotational driving force of motor 200 to be transmitted to engine 610, and the rotational driving force of engine 610 to be transmitted to motor 200. The motor 200 supplies the three-phase ac power output from the inverter 100 to the stator coil of the stator under the control of the control device 2, thereby rotating the rotor and generating a rotational driving force corresponding to the three-phase ac power.
That is, the motor 200 is controlled by the control device 2 to operate as an electric motor, while the rotor is rotated by receiving the rotational driving force of the engine 610 to operate as a generator that generates three-phase alternating current power.
The inverter 100 is a power conversion device that converts dc power supplied from a high-voltage (42V or 300V) power source, i.e., a high-voltage battery 622, into three-phase ac power, and controls three-phase ac current flowing through a stator coil of the motor 200 based on an operation command value and a magnetic pole position of a rotor.
The three-phase ac power generated by motor 200 is converted into dc power by inverter 100, and high-voltage battery 622 is charged. The high-voltage battery 622 is electrically connected to the low-voltage battery 623 via a DC/DC converter 624. The low-voltage battery 623 constitutes a low-voltage (14v) -based power source of the electric vehicle 600, and is a power source of a starter 625, a radio, a lamp, and the like for initially starting (cold starting) the engine 610.
When electric vehicle 600 is stopped (idle stop mode) such as a standby signal, engine 610 is stopped, and when engine 610 is restarted (hot start) at the time of restart, motor 200 is driven by inverter 100 to restart engine 610.
In the idle stop mode, when the charge amount of the high-voltage battery 622 is insufficient, or when the temperature of the engine 610 is not sufficiently raised, or the like, the driving is continued without stopping the engine 610. In the idle stop mode, it is necessary to secure a drive source for auxiliaries, such as a compressor of an air conditioner, which uses the engine 610 as a drive source. In this case, the motor 200 is driven to drive the auxiliary machine.
The motor 200 is also driven to assist the driving of the engine 610 when in the acceleration mode or in the high load operation mode. On the other hand, in a charging mode in which high-voltage battery 622 needs to be charged, engine 610 causes motor 200 to generate electric power to charge high-voltage battery 622. That is, motor 200 performs regenerative operation during braking or deceleration of electric vehicle 600.
The electric vehicle 600 includes: a control device 2 that issues a command to limit the three-phase alternating current applied to the motor 200 based on the temperature and flow rate of the insulating refrigerant; an inverter 100 that converts a dc voltage into an ac voltage by the limited PWM pulse output from the control device 2 to drive the motor 200; and a DC/DC converter 624 that boosts the direct voltage. This enables the insulating refrigerant 300 to be stably controlled even during driving of the vehicle.
The embodiments and the modifications described above are merely examples, and the present invention is not limited to these embodiments as long as the features of the invention are not impaired. In addition, although the various embodiments and modifications have been described above, the present invention is not limited to these. Other modes that can be conceived within the scope of the technical idea of the present invention are also included in the scope of the present invention.
Description of the symbols
1 electric system control device
2 inverter control device
3 Pump control device
10 current command operation unit
20 limiting part
30 current control part
40 PWM signal generating part
50 speed conversion part
100 inverter
110a U phase upper arm switch element
110b U phase lower arm switch element
110c V phase upper arm switch element
110d V phase lower arm switch element
110e W phase upper arm switch element
110f W phase lower arm switch element
200 motor
210 position sensor
220 current sensor
230 voltage sensor
300 insulating refrigerant
310 pump
320 refrigerant flow sensor
330 refrigerant temperature sensor
600 electric vehicle.
Claims (8)
1. A control device for an electric motor cooled by an insulating refrigerant circulated by a pump,
the control device is characterized by comprising:
a current command calculation unit that calculates a current command based on a torque command for the motor, a direct-current voltage applied from a power supply to a power conversion circuit, and a rotor position of the motor; and
and a limiting unit that limits a maximum value of a voltage applied to the motor based on the calculated current command, the calculated direct-current voltage, and the flow rate and temperature of the insulating refrigerant.
2. The control device according to claim 1,
the limiting unit limits the maximum value of the voltage by limiting a three-phase alternating current output from the power conversion circuit to the motor.
3. The control device according to claim 1,
the limiting unit calculates a dielectric strength of the motor based on a flow rate and a temperature of the insulating refrigerant, and limits a maximum value of the voltage based on the calculated dielectric strength.
4. The control device according to claim 3,
the limiting unit calculates a maximum value of the voltage from the current command and the direct-current voltage, and limits the maximum value of the voltage so that the maximum value of the voltage becomes smaller than the withstand voltage.
5. The control device according to claim 4,
the limiting unit calculates a maximum value of the voltage based on the current command, the direct-current voltage, and a temperature of a switching element of the power conversion circuit.
6. The control device according to claim 4,
the limiting unit calculates a maximum value of the voltage based on the current command, the direct-current voltage, and a gate voltage that drives a switching element of the power conversion circuit.
7. An electric vehicle, characterized in that,
a control device according to any one of claims 1 to 6.
8. A method for controlling a motor, comprising the steps of:
respectively calculating insulation resistance and leakage current according to the temperature and the flow of an insulation refrigerant circulating through a pump, and calculating the insulation withstand voltage of the motor according to the relation between the insulation resistance and the leakage current;
in the power conversion circuit, a relationship between a current and a maximum value of a voltage at the time of output, which differs depending on a voltage input to the switching element, is stored in advance, and the maximum value of the voltage is calculated from the relationship;
confirming that the insulation withstand voltage is greater than the calculated maximum value of the voltage; and
when the withstand voltage is smaller than the maximum value of the voltage, a current for limiting the maximum value of the voltage is calculated.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2019-200883 | 2019-11-05 | ||
| JP2019200883A JP7278926B2 (en) | 2019-11-05 | 2019-11-05 | Electric motor control device, electric vehicle, electric motor control method |
| PCT/JP2020/040244 WO2021090731A1 (en) | 2019-11-05 | 2020-10-27 | Control device for electric motor, electric vehicle, and control method for electric motor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114424450A true CN114424450A (en) | 2022-04-29 |
Family
ID=75848051
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202080066320.0A Pending CN114424450A (en) | 2019-11-05 | 2020-10-27 | Motor control device, electric vehicle, and motor control method |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JP7278926B2 (en) |
| CN (1) | CN114424450A (en) |
| WO (1) | WO2021090731A1 (en) |
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| US20030178999A1 (en) * | 2002-03-19 | 2003-09-25 | Emerson Electric Co. | Method and system for monitoring winding insulation resistance |
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| JP4575704B2 (en) | 2003-04-22 | 2010-11-04 | パナソニック株式会社 | Motor control device, compressor, air conditioner, and refrigerator |
| JP2006032651A (en) * | 2004-07-16 | 2006-02-02 | Mitsubishi Electric Corp | Electric apparatus |
| JP5217579B2 (en) * | 2007-08-06 | 2013-06-19 | 株式会社豊田自動織機 | Electric motor control method and control apparatus |
| WO2015140867A1 (en) | 2014-03-15 | 2015-09-24 | 三菱電機株式会社 | Motor drive control device, compressor, fan, and air-conditioning machine |
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- 2019-11-05 JP JP2019200883A patent/JP7278926B2/en active Active
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- 2020-10-27 WO PCT/JP2020/040244 patent/WO2021090731A1/en active Application Filing
- 2020-10-27 CN CN202080066320.0A patent/CN114424450A/en active Pending
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| CN1479965A (en) * | 2000-11-09 | 2004-03-03 | ͬ�Ϳ�ҵ��ʽ���� | Synchronous motor control method and device thereof |
| US20030178999A1 (en) * | 2002-03-19 | 2003-09-25 | Emerson Electric Co. | Method and system for monitoring winding insulation resistance |
| JP2005065353A (en) * | 2003-08-11 | 2005-03-10 | Toyota Motor Corp | Motor drive and automobile mounting it |
| JP2006141095A (en) * | 2004-11-10 | 2006-06-01 | Toyota Industries Corp | Device for controlling drive of permanent magnet type synchronous motor |
| CN102361774A (en) * | 2009-03-25 | 2012-02-22 | 三菱电机株式会社 | AC electric vehicle control device |
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Also Published As
| Publication number | Publication date |
|---|---|
| WO2021090731A1 (en) | 2021-05-14 |
| JP7278926B2 (en) | 2023-05-22 |
| JP2021078179A (en) | 2021-05-20 |
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