A high-efficiency hybrid series resonant DC-DC converter with boost converter as secondary for photovoltaic applications

Microconverters used for modular photovoltaic (PV) power conditioning systems require high efficiency over a wide input-voltage range. This paper introduces a series resonant converter through hybrid operation to meet this requirement. Under all input voltage conditions, the converter can achieve zero-voltage switching (ZVS) and/or zero-current switching (ZCS) of the primary-side devices and ZCS and/or ZVS of the secondary-side devices. The topologies and the three operation modes are introduced firstly. Especially, the steady state analysis based on the steady trajectories are presents in details. The design procedures of the power state are also introduced. The experimental results based on a 300-W prototype are given with 98.1% peak power stage efficiency and 97.6% CEC efficiency including all the auxiliary and control power under the 30V input voltage condition.