Differential Buck DC–DC Chopper Mode Inverters With High-Frequency Link

A circuit configuration and a circuit topological family of differential buck dc-dc chopper mode inverter with high-frequency link are proposed in this paper. The circuit configuration, the topology family, the instantaneous output voltage and the capacitance current feedback control strategy, the steady principle characteristic, and the design criteria for the key circuit parameters are fully investigated in this paper. The circuit configuration is differentially composed of two identical isolated bidirectional buck dc-dc choppers with the same input and output LC filters. These two choppers generate unipolarity sinusoidal pulse width modulation voltage waveforms with positive and negative half low-frequency cycle separately. Each dc-dc chopper consists of high frequency inverter, high frequency transformer, and high frequency rectifier. The circuit topological family includes six circuit topologies, namely, one-transistor forward mode, push-pull mode, push-pull forward mode, two-transistor forward mode, half-bridge mode, and full-bridge mode. Taking one-transistor mode circuit topology as example, the prototype is designed and implemented. The results from the theoretical analysis and principle test indicate that the inverters have advantages of high frequency galvanic isolation, simple topology, bidirectional power flow, single-stage power conversion, high conversion efficiency, high-quality output voltage waveform, and strong adaptability to various loads.