Experimental verification of the simplified mathematical model for harmonic distortion analysis in AC buck converter

This paper presents the results of an accuracy estimation of the previously proposed simplified mathematical model for harmonic distortion analysis in AC Buck converter. The experiment is performed using the designed prototype of the power converter with an induction motor. The results of the experiment are processed in Matlab in compliance with the digital signals processing theory. An accuracy of the proposed model is compared with an accuracy provided by the complex model based computer simulation. As the result the model is highly recommended to be used in various engineering tasks.

I. Introduction

AC Buck Converter, or AC Chopper, is a class of direct power electronic voltage converters, based on a well-known power circuit (Fig. 1) in various implementations (see [1]). This converter is perfectly suitable for such applications as voltage conditioning, soft start of induction motors, reactive power compensation and so on. The superior advantage of the Chopper converter over other well-known direct AC voltage converters is that operating with high switching frequency (much higher, than the line frequency) the harmonic distortion of converter currents and voltages can be easily attenuated by quite small and inexpensive line-and load-side filters [2]–[7]. Fig. 1.

a) The simplified circuit structure of AC buck converter (switching block), b) A waveform of the output voltage