LEAKAGE INDUCTANCE OPTIMIZATION FOR PHASE-SHIFTED FULL-BRIDGE DC-DC CONVERTER

When designing a high power Phase-Shifted Full-Bridge DC-DC (FSFB) converter for an Electrical Vehicle (EV), one of the main objectives is high efficiency across wide output load. Achieving high efficiency at half to full load is usually not difficult but at light load is always a challenge. For PSFB DC-DCconverters the main parameter for tuning the efficiency at light load is the leakage inductance. In this paper a more precise method for calculating the minimum leakage inductance for PSFB DC-DC converter will be investigated. The proposed method takes in the account all converter parameters like input and output voltage range, transformer and switching devices equivalent resistance and transformer magnetizing inductance. The optimum leakage inductance should ensure reaching the desired efficiency at specified load with minimum duty-cycle loss. The derived equations are validated in a numerical example and simulations.