Influence of Periodic Frequency Modulation Technology on Current Harmonic of Drive Motor

Permanent magnet synchronous motor is widely used in electric vehicles. The vibration and noise of motor will increase because the current harmonics concentrate near the switching frequency and its multiple frequency when the inverter with fixed switching frequency is used to drive the permanent magnet synchronous motor. This paper established a simulation model of the permanent magnet synchronous motor drive system by Matlab/SIMULINK, and the influence of the periodic frequency modulation on the motor current harmonic amplitude was studied in order to improve the NVH performance of the motor. Through the simulation result of different modulation models, it can be concluded that when periodic frequency modulation is adopted, the harmonic of output current signal is no longer concentrated at the switching frequency, and the harmonic amplitude is reduced; the sawtooth periodic frequency modulation has better effect on current harmonic suppression. In addition, the current harmonic optimization effect can be improved by reducing the modulation ratio of periodic frequency modulation, if the spread spectrum width is set reasonably, the frequency expansion range and the harmonic amplitude will decrease.