Harmonics Analysis in Various PWM Inverters Using the Fish Method

Abstract

The current and torque ripples of a motor are inevitably affected by the switching patterns of the inverter. They are closely related to the variations of the fish coordi- nates. The harmonics effect on a motor can thereby be demonstrated by the figure of the quality measure that indicates the size of the flux fish. In this article, the fish method is originally applied to analyze the harmonics in VSV-PWM, S-PWM inverters and the flux hysteresis control of the DTC. With the help of THD measurements, it is verified that the fish method can be successfully applied to compare the harmonics effects of various switching patterns on the induction motors.Keywords direct torque control (DTC), figure of the quality measure, fish method, flux hysteresis control, S-PWM, VSV-PWM