Parallel Inverter System Efficiency Improvement Using Alternative Adaptive Droop Control

Inverters have excessively low efficiency while operating at low power levels, leading to a low light load efficiency if equal power sharing is implemented using the conventional droop control. This paper presents an alternative adaptive droop strategy to automatically use an optimal number of parallel inverters at any given power level to enhance the overall efficiency of the system without any communication. The proposed method is applied to a system with two single-phase parallel inverters, and simulation and experimental results verify the satisfactory and reliable performance of the proposed method. Furthermore, it is observed that using the proposed method, the system efficiency improves up to 7.5% at light loads in comparison with the conventional droop control.