Research of the influence of different PWM inverters on the eddy current losses of induction motors

Frequency control of motor which is fed by PWM inverters is applied in extensive fields. SPWM and SVPWM are two universal modulation patterns. However, the AC drive technology based on PWM inverters brings some bad effects on motors. In this paper, with the mechanism of generating motor-iron losses as a starting point, and with three-phase asynchronous motor as a study object, calculation and analysis of eddy current losses under the SVPWM modulation are completed via harmonic analysis method, time-stepping finite element analysis (FEA) method respectively, and the influences of carrier wave ratio and modulation index on the eddy current losses are studied also. Meanwhile, the comparison study of eddy current losses between SPWM and SVPWM is implemented. Finally, the experiments of losses are carried out and the results show that the SVPWM scheme has smaller losses, which offers references for choosing a suitable motor system.