Microcontroller Based Light Load Efficiency Optimization for an AC-DC Converter

In this paper the method of maintaining high power conversion efficiency across the entire load range and its simple microcontroller based circuit implementation is described. This method substantially increases the conversion efficiency at light loads by minimizing switching and driving losses of semiconductor switches, core losses of the magnetic components, as well as transformer losses. These losses are minimized by periodically turning OFF and ON of the power converter. The converter is turned ON only when it operates at power level that exhibits the maximum efficiency and turned OFF at low load and supplied through the battery which is charged simultaneously during high load condition where efficiency is maximum. So eliminating the constant losses which are independent on any load, the efficiency of the system gets improved to considerable amount. The proposed method is implemented for 230/12V single phase fully controlled rectifier.