Abstract: Several working modes of the synchronous AC/DC converters are introduced in this paper.The synchronous converters are composed of two main parts:DC componant generation and DC power extraction.The basic working modes are 50 Hz single peak waves,100 Hz SPW and 50 Hz double peak waves.The realized circutis working in those modes are proposed.The external characteristics of those circuits are compared and examed.Experimental results are also provided.