This paper proposes estimation control method of bilateral series resonant inverter for high frequency link UPS. Proposed inverter consists of a zero current switched series resonant converter, a high frequency transformer and a zero current switched cycloconverter. Thus bidirectional power flow is possible and high efficiency is obtained. Proposed control method enables us to minimize the isolation transformer and the output viltage ripple by controlling the resonant tank energy while the switching pattern of the cycloconverter is fixed. Estimation control method is verified by computer simulation and experiment.
