Power electronic transformer with reduced number of switches: Analysis of clamp circuit for leakage energy commutation

High frequency linked ac/ac converters are important in harnessing energy from renewable energy sources and connecting them to the high voltage ac grid. Theoretically, these converters provide single stage power conversion and obviates the need for any storage elements. Any switching transition in the load side converter causes overvoltages due to the presence of non-ideal leakage inductances in the windings of the high frequency transformer. A clamp circuit is needed for commutation of this leakage energy and to protect the power electronic devices. This paper provides a detailed analysis of the power loss incurred in the clamp circuit along with a method to design the clamp components. The entire circuit has been simulated along with non-ideal leakage inductance and the presented simulation results confirm the analytical predictions.