Overlap time and voltage drop compensation in an AC/AC converter

This paper presents an AC/DC converter system utilizing an AC/AC direct converter and an inverter with a medium frequency isolating transformer. The operation of the AC/AC converter is based on soft commutation technique. Overlap time has been introduced for a proper zero current switching operation of the AC/AC converter. During operation, the current through the medium frequency transformer causes a voltage drop due to copper losses. These two phenomena result in deviations from the actual operation of the AC/AC cycloconverter. In this paper, a compensation technique is proposed by deriving the related formulas for nonideal operating conditions. With such compensation, the overall system will react dynamically to the changing conditions faster and the error in steady state operation is minimized. The simulation results verify the feasibility of the proposed compensation scheme for a better performance and faster dynamics.