Research On Low Voltage Input Inverters

With the further development of new energy power generation and energy storage technologies,low-voltage power battery has been widely used. The need for low-voltage DC power to daily ACpower conversion keeps increasing. Low voltage input inverters have a very good developingprospects in the commercial and civilian products.The applicability of the high frequency link single staged flyback inverter and its active clampsoft-switching technology in a small power conversion occasion, is analyzed and demonstrated. Basedon high frequency link technology, an active clamped flyback inverter and a low-frequency mixedreversal bridge are selected to achieve solutions for micro PV inverter. Ooutput current closed-loopcontrol and MPPT algorithm with voltage feed-forward are adopted for micro PV inverter’s real-timeconditioning. A230W prototype is developed and high efficiency of94.2%is achieved at nominalinput of35V. The topology of flyback inverter with output rectifier using full controlled powerelectronic devices to achieve bidirectional energy flow, which is a suitable solution for the smallpower aviation static inverters, is studied.Two-stage structure is studied for larger power conversion solutions. Implementation of the DCconverter with high voltage gain and high efficiency of the first stage in a two-stage structure isstudied in the first place. Problems, existing in dual-inductor current-fed half bridge converters, ofdifficulties in leakage inductor design and zero-crossing-current resonance as well as their solutionsare studied. A1kW prototype with28V input and180V output is developed and efficiency of92.5%isachieved. Technologies of leakage inductor energy recycling and interleaved current sharing in aflyback converter with output voltage doubler are studied. A1kW prototype with28V input and180Voutput is developed and its efficiency reaches up to93.9%.Inverters of the second stage in two-stage structures are studied at last. Some modulationmethods used in a dual buck full-bridge inverter are discussed in this paper. Some of the ways toimprove efficiency and reduce volume and weight are proposed. Experimental results are given outand efficiency of97.5%is achieved under1kW nominal power.