The solution of harmonic restriction for motor speed regulation

An EMC standard for higher request of restriction on harmonic currents is administrated compulsively since 2001. The harmonic current generated by motor speed regulation is harmful to the power system. It must be regulated within the limits according with new EMC standards. The traditional regulation method cannot pass these standards. The new solutions are found here after analyzing and simulating the performance of on-off modulation and high frequency modulation.