Three-leg PWM Current Source Converter with AC Chopper for Single-phase Utility

Abstract

A single-phase PWM current source converter with three legs is proposed in this paper. The converter consists of main bridge circuit and ac chopper circuit, and a leg is commonly used for both circuits that are connected in parallel. The ac chopper with the PWM operation outputs the double-frequency ac voltage in the dc side, which cancels the dc pulsation of the main bridge. The pulsation-free dc voltage of the converter leads to the smooth dc current and the sinusoidal utility current. This allows the dc inductor to be greatly reduced. The experiments prove that the converter has good waveforms in small dc inductance. Moreover, the harmonic components of the currents are derived from the PWM switching pattern and are compared with measured ones. Theoretical results can be utilized for the determination of the circuit parameters in values.