# US 2021/0281201 A1 · Motor-driven compressor

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- Number: US 2021/0281201 A1
- Document ID: US20210281201A1
- Status: Published application
- Kind: A1
- Application number: 17/189,451
- Filed: 2021-03-02
- Published: 2021-09-09
- Earliest claimed: 2020-03-06
- Assignees: Kabushiki Kaisha Toyota Jidoshokki
- Applicants: Kabushiki Kaisha Toyota Jidoshokki
- Inventors: Takuya NARUSE; Kazuki NAJIMA
- Web page: https://patentgrep.com/patent/US20210281201A1

## CPC

- H02P 21/22: Current control, e.g. using a current control loop
- B60H 1/143: {the heat being derived from cooling an electric component, e.g. electric motors, electric circuits, fuel cells or batteries}
- F25B 31/026: {with compressor of rotary type}
- F25B 49/025: {Motor control arrangements}
- H02P 21/18: Estimation of position or speed
- H02P 27/12: pulsing by guiding the flux vector, current vector or voltage vector on a circle or a closed curve, e.g. for direct torque control
- H02P 29/62: for raising the temperature of the motor
- F25B 2400/01: Heaters
- F25B 2500/31: Low ambient temperatures
- F25B 2600/021: Inverters therefor
- H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- B60H: ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
- F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS

## Abstract

The motor-driven compressor includes an electric motor, a housing, a compression portion, and an inverter device. The inverter device includes an inverter circuit, a current sensor, a coordinate converter, a speed controller, a current controller, a PWM controller, and a rotation angle estimator. The speed controller generates a d-axis current command value and a q-axis current command value such that a necessary torque to drive the electric motor occurs. The inverter device includes a heat-generating current command section that increases a temperature of the electric motor by changing the d-axis current command value and the q-axis current command value. The heat-generating current command section changes the d-axis current command value and the q-axis current command value so as to shift them in a direction in which a d-axis current value increases along a constant torque curve in a d-q coordinate system.

## Claims

### Claim 1

A motor-driven compressor, comprising:
an electric motor;
a housing that accommodates the electric motor and includes a suction port into which a refrigerant is drawn;
a compression portion configured to be driven by the electric motor and configured to draw in and compress the refrigerant in the housing; and
an inverter device configured to drive the electric motor, wherein
the inverter device includes
an inverter circuit including switching elements included in upper arms and lower arms of u-, v-, w-phases, the inverter circuit being configured to convert direct-current voltage into alternating-current voltage when switching operation for the switching elements is performed and supply the alternating-current voltage to the electric motor,
a current sensor configured to detect a value of current supplied to the electric motor,
a coordinate converter configured to calculate a d-axis current value and a q-axis current value using a detected value of the current sensor,
a speed controller configured to generate a d-axis current command value and a q-axis current command value using a difference between a rotation speed command value and a rotation speed estimated value for the electric motor,
a current controller configured to calculate a d-axis voltage command value using a difference between the d-axis current command value and the d-axis current value and calculate a q-axis voltage command value using a difference between the q-axis current command value and the q-axis current value,
a pulse-width-modulation controller configured to control the switching elements using the d-axis voltage command value and the q-axis voltage command value, and
a rotation speed estimator configured to calculate the rotation speed estimated value using the d-axis current value, the q-axis current value, the d-axis voltage command value, and the q-axis voltage command value,
the speed controller generates the d-axis current command value and the q-axis current command value such that necessary torque to drive the electric motor occurs,
the inverter device includes a heat-generating current command section configured to increase a temperature of the electric motor by changing the d-axis current command value and the q-axis current command value, and
the heat-generating current command section is configured to change the d-axis current command value and the q-axis current command value so as to shift the d-axis current command value and the q-axis current command value in a direction in which the d-axis current value increases along a constant torque curve in a d-q coordinate system.

### Claim 2 (depends on 1)

The motor-driven compressor according to claim 1, wherein the heat-generating current command section is configured to change the d-axis current command value and the q-axis current command value so as to shift the d-axis current command value and the q-axis current command value in a direction in which the d-axis current value decreases along the constant torque curve when a difference between the rotation speed command value and the rotation speed estimated value is greater than a threshold value.

### Claim 3 (depends on 1)

The motor-driven compressor according to claim 1, wherein the heat-generating current command section is configured to, in the d-q coordinate system, define a current upper limit circle in a range that is not greater than a limit current value for a temperature of a component of the inverter circuit and change the d-axis current command value and the q-axis current command value so as to shift the d-axis current command value and the q-axis current command value to an intersection point of the current upper limit circle and the constant torque curve.