Analysis of Power Flow in a Power Converter

Abstract

Power converters have been widely used in many industrial applications. On the ac-side of such converters, the current is distorted because of the nonlinearity of the power devices even when the source voltage is sinusoidal. This leads that the power converter is regarded as a harmonic-current source. The harmonic current is one of the most important factors in the analysis of converters. This paper analyzes power flow of a power converter that behaves synchronously with the line frequency. For example, power-flow analysis in a three-phase diode converter with a resistance on the ac-side is presented; the analysis was compared with the conventional analysis with the assumption that the ratio of the resistance on the ac-side to that on the dc-side is very small. The proposed power flow concept enables electrical engineers and students to discuss rationally the power flow of a converter.