Traction battery self-heating control method and device

A motor controller, comprising:

• a memory, is configured to storing computer-executed instructions;
• a processor, is configured to acquire a second temperature of a rotor according to system parameters and a first temperature of a rotor of a permanent magnet motor;
• wherein the system parameters comprise:
• a material specific heat capacity of the rotor, a mass of the rotor, and a power for heating the rotor in a sampling time interval, the first temperature is a temperature of the rotor at a first sampling time, the second temperature is a temperature of the rotor at a second sampling time, the second sampling time is a current sampling time, and the first sampling time is a previous sampling time of the second sampling time;
• the processor is configured to estimate a third temperature of the rotor according to the first temperature and the second temperature, wherein the third temperature is a temperature of the rotor at a third sampling time, and the third sampling time is a next sampling time of the second sampling time;
• and
• the processor is configured to stop self-heating of the traction battery when the third temperature reaches a demagnetization temperature of the rotor.