CN-116985640-B - Electric drive system, power assembly, heating method and electric vehicle

CN116985640BCN 116985640 BCN116985640 BCN 116985640BCN-116985640-B

Abstract

The application discloses a motor controller, a power assembly and an electric vehicle, and relates to the technical field of electric vehicles. The motor controller comprises an inverter circuit, a direct current-direct current conversion circuit and a controller. The input end of the inverter circuit is connected with the input end of the motor controller, and the output end of the inverter circuit is connected with the three-phase motor winding of the electro-magnetic synchronous motor. The input end of the direct current-direct current conversion circuit is connected with the input end of the electric drive system, and the output end of the direct current-direct current conversion circuit is connected with the exciting winding of the electric exciting synchronous motor. The inverter circuit converts the direct current into three-phase current and supplies the three-phase current to the three-phase motor windings. The DC-DC conversion circuit converts DC power and supplies the converted DC power to the exciting winding. The controller is used for controlling the inverter circuit and the direct current-direct current conversion circuit so that the temperature of the power battery pack is greater than or equal to a first temperature threshold value. By using the scheme, a heating device is not required to be arranged when the power battery pack is heated, so that the cost is reduced and the space is saved.

Inventors

LI HAOJIE
WU CHAOQIANG
LIN MENGXUAN

Assignees

华为数字能源技术有限公司

Dates

Publication Date: 20260508
Application Date: 20210330

Claims (14)

1. The utility model provides a motor controller, its characterized in that, motor controller's input is used for connecting power battery, motor controller's output is used for connecting the electro-magnetic synchronous motor, motor controller includes inverter circuit, direct current-direct current conversion circuit and controller, wherein: the input end of the inverter circuit is used for being connected with the input end of the motor controller, the inverter circuit comprises three inverter bridge arms, the middle point of each inverter bridge arm is respectively used for being connected with one phase winding of three-phase windings of the electro-excited synchronous motor, and the inverter circuit is used for converting direct current from the power battery pack into three-phase current to supply power for the three-phase windings; the input end of the direct current-direct current conversion circuit is used for being connected with the input end of the motor controller, the output end of the direct current-direct current conversion circuit is used for being connected with the exciting winding of the electric excitation synchronous motor, and the direct current-direct current conversion circuit is used for carrying out direct current conversion and then providing the direct current to the exciting winding; The controller is used for: And controlling the inverter circuit to output the three-phase current to heat the three-phase winding in response to the temperature of the power battery pack being lower than a first temperature threshold, or controlling the direct current-direct current conversion circuit to output exciting current to the exciting winding to heat the exciting winding, wherein the heat of the exciting winding is used for heating the power battery pack.
2. The motor controller of claim 1, wherein the controller is configured to: And controlling the inverter circuit to output three-phase current to the three-phase winding in response to the temperature of the power battery pack being lower than the first temperature threshold value so as to enable d-axis current of the electro-magnetic synchronous motor to be first preset d-axis current and q-axis current to be zero, and controlling the direct current-direct current conversion circuit to stop working.
3. The motor controller of claim 1, wherein the controller is configured to: And controlling the inverter circuit to output three-phase current to the three-phase winding in response to the temperature of the power battery pack being lower than the first temperature threshold value so as to enable d-axis current of the electric excitation synchronous motor to be first preset d-axis current and q-axis current to be zero, and controlling the direct current-direct current conversion circuit to output exciting current to the exciting winding.
4. The motor controller of claim 1, wherein the controller is configured to: in response to an electric vehicle being in a running state and a temperature of the power battery pack being lower than the first temperature threshold, the direct current-direct current conversion circuit is controlled to increase the exciting current output to the exciting winding, and the inverter circuit is controlled to increase the three-phase current output to the three-phase winding, the exciting current and the three-phase current making an output torque of the electric excitation synchronous motor be a current required torque.
5. The motor controller according to any one of claims 1 to 4, wherein the controller is configured to: And controlling the direct current-direct current conversion circuit to reduce the exciting current in response to the rotor temperature of the electrically excited synchronous motor being greater than a second temperature threshold.
6. The motor controller of claim 5, wherein the controller is configured to: And controlling the direct current-direct current conversion circuit to reduce the exciting current and controlling the inverter circuit to increase the three-phase current in response to the rotor temperature of the electrically excited synchronous motor being greater than the second temperature threshold and the electrically excited synchronous motor outputting torque.
7. A motor controller according to claim 2 or 3, wherein the controller is adapted to: and controlling the inverter circuit to maintain the q-axis current at zero and reduce the first preset d-axis current in response to the stator temperature of the electrically excited synchronous motor being greater than a third temperature threshold.
8. The motor controller of claim 1, wherein the controller is configured to: And controlling an inverter circuit to reduce the three-phase current and controlling a direct current-direct current conversion circuit to increase the exciting current when the stator temperature of the electrically excited synchronous motor is greater than a third temperature threshold.
9. The motor controller according to any one of claims 1 to 4, wherein the controller includes a data table for calibrating a correspondence between a temperature of the power battery pack and a magnitude of the exciting current, the controller being configured to: And adjusting the exciting current of the exciting winding according to the temperature of the power battery pack so that the relationship between the temperature of the power battery pack and the exciting current of the exciting winding accords with the corresponding relationship calibrated by the data sheet.
10. A motor controller according to claim 2 or 3, wherein the controller is configured to determine the amplitude and phase of the three-phase current from the first preset d-axis current.
11. The power assembly is characterized by comprising a motor controller and an electric excitation synchronous motor, wherein the motor controller comprises an inverter circuit, a direct current-direct current conversion circuit and a controller, the electric excitation synchronous motor comprises a stator and a rotor, the stator comprises a three-phase winding, and the rotor comprises an excitation winding; The input end of the electric excitation synchronous motor is used for being connected with the output end of the motor controller, the inverter circuit comprises three inverter bridge arms, the midpoints of the three inverter bridge arms are respectively connected with the three-phase windings of the electric excitation synchronous motor, and the inverter circuit is used for converting direct current from a power battery pack into three-phase current to supply power for the three-phase windings; The input end of the direct current-direct current conversion circuit is used for being connected with the input end of the motor controller, the output end of the direct current-direct current conversion circuit is used for being connected with the exciting winding of the electric excitation synchronous motor, and the direct current-direct current conversion circuit is used for carrying out direct current conversion on the direct current and then providing the direct current to the exciting winding; The motor controller is used for: and controlling the inverter circuit to output the three-phase current to heat the three-phase winding in response to the temperature of the power battery pack being lower than a first threshold value, wherein the heat of the three-phase winding is used for heating the power battery pack, or controlling the direct current-direct current conversion circuit to output the exciting current to heat the exciting winding, and the heat of the exciting winding is used for heating the power battery pack.
12. The powertrain of claim 11, including a cooling circuit including a cooling medium for conducting heat generated by the field windings and the three-phase windings of the electrically excited synchronous motor to the power battery pack.
13. The powertrain of claim 12, wherein the cooling medium is configured to conduct heat from the motor controller to the power battery pack.
14. An electric vehicle comprising a motor controller according to any one of claims 1-10 or comprising a powertrain according to any one of claims 11-13.

Description

Electric drive system, power assembly, heating method and electric vehicle The present application is a divisional application, the application number of which is 202180003101.2, and the entire content of which is the original application of 2021, 03 and 30. Technical Field The application relates to the technical field of electric vehicles, in particular to an electric drive system, a power assembly, a heating method and an electric vehicle. Background With the increase of energy shortage and environmental pollution problems in modern society, electric vehicles have received attention as new energy vehicles in various fields. The electric vehicle is powered by a power battery pack and is converted by an electric machine into mechanical energy to drive the electric vehicle. With electric vehicles being deployed in large numbers, many electric vehicles are used in areas that are cold in winter, or areas that are cold at any time. In a low-temperature environment, the viscosity of electrolyte in the power battery pack is increased, so that the discharge performance of the power battery pack is reduced. Therefore, the power battery pack needs to be provided with high-efficiency low-temperature heating measures, and the power battery pack can work in a safe temperature range. The prior art heats the power battery pack by adding a heating device. Referring to fig. 1, a schematic diagram of a heating device for a power battery pack according to the prior art is shown. The heating device comprises a positive temperature coefficient (Positive Temperature Coefficient, PTC) resistor Rp and a controllable switching tube S. Rp and S are connected in series and then connected in parallel with a bus capacitor Co of the electric vehicle. When the Battery management system (Battery MANAGEMENT SYSTEM, BMS) of the electric vehicle determines that the Battery temperature is low, the control S is closed, rp is connected to the circuit to release heat, and the power Battery pack 10 is heated. But this heating requires the addition of additional heating means, takes up space and increases costs. Disclosure of Invention The application provides an electric drive system, a power assembly, a heating method and an electric vehicle, wherein an additional heating device is not required to be added when a power battery pack is heated, so that the cost is reduced and the space is saved. In a first aspect, the present application provides an electric drive system, an input end of the electric drive system is connected to a power battery pack, and an output end of the electric drive system is connected to an electrically excited synchronous motor. The electric drive system includes an inverter circuit, a Direct Current (DC) -DC conversion circuit, and a controller. The input end of the inverter circuit is connected with the input end of the electric drive system, the output end of the inverter circuit is connected with the three-phase winding of the electro-magnetic synchronous motor, and the inverter circuit converts direct current provided by the power battery pack into alternating current and provides the alternating current for the three-phase winding, namely the inverter circuit is used for outputting three-phase current to the motor. The input end of the direct current-direct current conversion circuit is connected with the input end of the electric drive system, the output end of the direct current-direct current conversion circuit is connected with the exciting winding of the electric excitation synchronous motor, and the direct current provided by the power battery pack is provided for the exciting winding after being subjected to direct current conversion by the direct current-direct current conversion circuit, namely the direct current-direct current conversion circuit is used for outputting exciting current. The controller is used for controlling the inverter circuit and the direct current-direct current conversion circuit, further adjusting the three-phase current output by the inverter circuit and adjusting the exciting current output by the direct current-direct current conversion circuit, so that the temperature of the power battery pack is greater than or equal to a first temperature threshold value. By utilizing the technical scheme provided by the application, the power battery pack is heated by the heat generated by the electric drive system and the electric excitation synchronous motor, specifically, the heating power of the three-phase winding can be adjusted by adjusting the three-phase current output by the inverter circuit, the heating power of the excitation winding can be adjusted by adjusting the exciting current output by the direct current-direct current conversion circuit, and the power battery pack is heated by the heat generated by the three-phase winding and the excitation winding and the heat generated by the power switch device in the electric drive system without adding an additional heating device, so