Efficiency Enhanced Burst Mode Control Strategy for Microinverters

Due to the trend of renewable energy, photovoltaic (PV) inverters are widely used around the world. Inverter's efficiency significantly decreases at low input power, and microinverters spend a significant percentage of the year operating at that case. Achieving high conversion efficiency is the key to improving total efficiency. A burst mode parameter design method is proposed in this paper, which aims to improve efficiency by designing the burst mode's upper bound voltage and switching case based on tradeoff between inverter efficiency and maximum power point tracking (MPPT) efficiency. Then, a simple MPPT strategy for burst mode is implemented. Finally, experimental tests are performed, verifying the efficiency improvements of proposed strategy. The experimental results show that the proposed strategy achieves a combined efficiency of 92.53%, which allows more solar power to be available to the users and the grid.