Efficient Variable Switching Frequency Drive Control Method for Propulsion Motors

Nearby space vehicles are facing energy shortages at night, and the night propulsion motors are mostly in a low - speed and light load state. The main driver loss is switch loss. Reducing the switch frequency can effectively reduce switch loss, but it will increase the AC copper loss of the motor and the ripple and harmonic of the inverter. The article proposes a variable switching frequency modulation method that can update the switching frequency to the optimal switching frequency in a timely manner with the current speed and torque as inputs, in order to optimize the efficiency of the electric propulsion system. Starting from studying the impact mechanism of switch frequency on the motor system, quantify the impact of switch frequency on the efficiency, current quality, and motor copper loss of the driver; Establish a system total loss simulation model based on quantitative results with current quality as constraints; Different working conditions are set according to the load spectrum, and the Simulated annealing algorithm is used to calculate the optimal switching frequency under different working conditions. The resultant torque and speed are taken as the input, and the optimal switching frequency is taken as the output function; Design a DSP algorithm based on this function, update the switch frequency in a timely manner according to the current operating conditions, and obtain a variable switch frequency drive control method; Finally, taking the high-power propeller propulsion motor system as an example, simulation verifies the effectiveness of the variable switching frequency modulation method.