Analysis of the Effect of the Parasitic Capacitance of Switch Devices on Current Distortions of Voltage Source Rectifier

Deadtime produces current distortion in voltage source PWM converters, especially for high switching frequency PWM converters. The deadtime voltage error considering the effect of parasitic capacitance of switch devices is analyzed. The fast Fourier transform (FFT) of deadtime voltage error within a line frequency period is given. The (6n±1)th harmonic spectrums of the deadtime voltage error with different parasitic capacitances are shown. As parasitic capacitance increases, the (6n±1)th harmonics of the deadtime voltage error decreases, thus the current harmonics of three-phase voltage source rectifier (VSR) decreases. Simulation results of the MATLAB/SIMULINK model are given to verify the theoretical analysis of the effect of parasitic capacitance on current distortions of three-phase VSR.