An improved algorithm for harmonic suppression of VVVF

In many motor speed control systems, SPWM is an excellent method used in VVVF, meanwhile the harmonic component of its output wave impairs the applications in engineering practices. Through investigation on the principle of SPWM and explicit elimination procedure, an improved algorithm for the harmonic suppression is presented for SPWM, which is a designated harmonic suppression technology in high voltage and high frequency spectrum. This algorithm is based on improving SPWM sampling process and is approached with model analysis and Fourier series transform method so that the real time calculation and control circuit make a reality. As is applied in whole speed adjusting range, the voltage can be conveniently controlled and high frequency harmonic components of SPWM are also improved.