A Single-Stage Soft-Switching AC/DC Converter without Soft-Switching Auxiliary Circuit

This paper proposed a single-stage soft-switching AC/DC converter without soft-switching auxiliary circuit. The proposed AC/DC converter only uses two main active switches to execute the input power factor correction and regulate the output dc voltage magnitude. Thus, the input power factor is high and the input current distortion is low on the ac input side. Moreover, the output DC voltage is stable and its ripple is low. Although the proposed AC/DC converter does not include soft-switching auxiliary circuit, the all main semiconductors can switch at soft-switching condition. Thus, the circuit topology is simple and the circuit cost is low. Furthermore, the proposed AC/DC converter does not also include front-end four-diode rectifier on the ac input side. The conduction losses can also be reduced. The proposed AC/DC converter uses a simple frequency modulation control strategy to synthesize a low harmonics sinusoidal input current waveform and achieve well dynamic regulation function. A design example of 600W single-stage soft-switching AC/DC converter is examined to assess its performance.