Switching frequency is one of the main deciding factors in development of a power converter system for aerospace applications. The filter is one of the major components that significantly contribute to the overall system weight and efficiency. The design of the filter, including inductor and capacitor is determined by the switching frequency. On the other hand, the device switching loss is proportional to the loss, which in turn changes the design of thermal system. Thus selection of optimal switching frequency is essential for power converter systems used in aerospace industry. The objective of this study is to select the optimal switching frequency when the overall converter weight is minimal. In this study, switching frequencies ranging from 9kHz to 20kHz is selected based on current IGBT technology. Proven design algorithm for passive filter is adopted in the optimization. Partial verification for power efficiency is conducted via simulation and experiment results.