Contrastive research on different bus_clamping PWM methods

CUI Lin, CHEN Yangsheng

(College of Electrical Engineering, Zhejiang University, Hangzhou 310027, China)

Abstract: In order to reduce switching losses of power device, several typical types of busclamping pulse width modulation(BCPWM) were realized by reasonably selecting and placing the zero vectors on the basis of classical space vector pulse width modulation(CSVPWM). Harmonics of currents and the wave form of voltages were studied and compared. Then the switching losses were calculated and different influence on the motor bearing due to the fluctuations of voltage to neural were explained. Finally, the feasibility of BCPWM was testified by experimental study. The simulation results indicate that compared with CSVPWM, BCPWM can effectively reduce the switching losses, especially which of BCPWM3 that adopts the zero vectors dynamically according to the power factor angle of the load. In the meantime, BCPWM increases the total harmonic distortion(THD) of currents. The fluctuations of voltage to neural are larger in BCPWM2 and BCPWM3, which aggravate the damage of motor bearing.

Key words: busclamping pulse width modulation(BCPWM); harmonic; switching losses; voltages to neutral; total harmonic distortion(THD)