[rare Earth Forum] Application of permanent Magnet Synchronize Motor in Electric vehicles: common motors, Drive system requirements and Technical Development

SMM10 March 15: at the 2020 China rare Earth permanent Magnet Industry Market Application and Development Forum held by SMM, Cheng Fangbin, a PhD technical expert from Jinlong United Automotive Industry (Suzhou) Co., Ltd., gave a speech on the theme "Technical requirements and trends of permanent magnet Synchronize motor applications in electric vehicles". The electric drive requirements of new energy vehicles, permanent magnet Synchronize motor and its development characteristics and trends are introduced in detail.

Requirements of new energy on motor drive system

New energy has specific requirements for motor drive system, such as power density and energy density, torque response, speed regulation range, efficiency, regenerative braking, reliability, electromagnetic compatibility, safety and so on.

Technical specifications of motor drive system

Performance parameters requirements of driving motor for new energy bus

Common motors for new energy vehicles

DC motor

Low cost, easy to control, good speed regulation performance;

The utility model has the advantages of complex structure, low speed, large volume and frequent maintenance.

Has been eliminated

Ac asynchronous motor

The utility model has the advantages of simple structure, durability, low cost, low torque ripple, low noise, high limit speed and reliable operation.

Low power density, low efficiency and poor speed regulation;

Small batch applications: Tesla Model S, ES8.

Switched reluctance motor

The utility model has the advantages of compact and firm structure, suitable for high-speed operation, low cost, wide speed regulation range and reliable operation.

Large torque ripple, high noise, low power density and low efficiency;

Very small batch application: new energy bus.

Permanent magnet Synchronize motor

High torque density, high efficiency, high power density, wide speed regulation range and small volume;

The manufacturing process is complex, the cost is high, and the magnetic property declines at high temperature.

Mass applications: Tesla Moedl3, ES6, BYD Tang, BAIC EU series, Xiaopeng G3, Weima EX5 and so on.

Technical Development characteristics and Development trend of permanent Magnet Drive Motor

High efficiency: to ensure the high and low speed comprehensive efficiency of the motor, that is, to ensure a wide enough high efficiency area, so that the vehicle is in an efficient state under most operating conditions, and to ensure that each kilowatt-hour of electricity can be of maximum use.

Deep integration: deep integration of drive motor, motor controller and reducer, electric drive integration is the main technical goal of the future development of passenger vehicles.

Low cost: heavy rare earth intergranular diffusion (GBD) and grain boundary adjustment (GBM) technology can greatly reduce the amount of heavy rare earth, improve the properties of magnets and improve the quality.

High speed: under the constraint of constant output torque and power of the motor, the maximum speed of the drive motor is increased, the volume and weight of the motor are reduced, and the level of power density is further improved.

High power density: the national key research and development plan of new energy vehicles in the 13th five-year Plan points out that the peak power in 2020 is 4.0kW / kg, and the continuous power density is 2.2.kW/kg.