Braking Torque Analysis and Control Method of a New Motor with Eddy-Current Braking and Heating System for Electric Vehicle

To solve the problem of the serious mileage reduction of electric vehicles in winter, this paper introduces a new type of motor with eddy current braking and heating system (EBHS). EBHS can convert the vehicle’s kinetic energy into the thermal energy which can be used for heating the cabin and the battery at the right temperature. This paper proposes the structural layout and operating modes with the novel motor. The air gap magnetic density of the ECR is calculated by the magnetic circuit method. The braking torque is solved by the transient electromagnetic finite element method. The eddy current loss power at different speeds is used for analyzing heat performance. Based on MATLAB/Simulink environment, the fuzzy control method is used to simulate the EBHS’s braking energy efficiency. Compared with PTC heating, the power consumption of the new motor is reduced by 25 % and the cabin can reach 20 °C in 160 seconds. Finally, it is verified by bench test that the retarder stator stayed within 110 °C when it is continuously operated for 12 minutes. The braking torque of the finite element analysis result meet the test value, and the error rate is not higher than 11.7 %.