Power processor for interfacing battery storage system to 725 V DC bus

The paper presents two high power, high frequency DC-DC power processors utilising a single phase AC link that is suitable for low voltage DC distribution systems. Expressions for active and apparent power transmitted through the isolation transformer and the primary side power factor are derived. The analysis accounts for the contribution made by harmonics towards power transmission. In the available literature, analysis of similar power processors ignores harmonics and assumes sinusoidal voltage and current waveform variation. It will be shown that ignoring power transfer due to harmonics leads to significantly lower calculated values of active and apparent power and to higher values of operating power factor compared with those obtained in practice. The best operating range of phase shift to ensure operation with high energy efficiency is identified. The effects of parasitic components on performance are also investigated. Simulation and analytical results for a 10 kW converter interconnecting 68-75/725 V DC busses are presented. Experimental results taken at a lower input voltage (24 V instead of 72) are also included to validate the simulation waveforms