Introduction of the Harmonic Distortion Determining Factor and its Application to Evaluating Real Time PWM Methods

Abstract

Frequency spectra of inverter output currents are one of the important factors to evaluate PWM methods. These spectra are, however, influenced not only by the PWM method itself but by the operating conditions of the inverter such as the switching frequency or load parameters. The harmonic distortion determining factor (HDDF) is considered to be a common quality index that represents the intrinsic spectral property of individual PWM methods. As it has a close relation to RMS values of the harmonic current or torque ripples of driven motors and, further, it is almost independent of the operating conditions, HDDF is quite useful for evaluating PWM methods. In this paper four typical carrier based PWM methods and two space vector based PWM methods are compared and evaluated based on the HDDF values. © 1995, The Institute of Electrical Engineers of Japan. All rights reserved.