Communicationless Parallel Inverters Based on Inductor Current Feedback Control

Conventional parallel inverter system always includes control functions for interconnections. It is challenging to develop an effective control method for seamless parallel connection for multi-inverters. A communicationless digital parallel inverter system is designed and developed by the authors and reported in this paper. Considering the influence of resistance on the output impedance of an inverter and on its power characteristic, the system is controlled by dual closed-loops of instantaneous output voltage and inductor current feedbacks. This control strategy can improve the output performance of the inverter and allows more accurate applications of the droop theory for parallel inverters. The communicationless paralleling operation of two 1kW inverters controlled by DSP (Digital Signal Processor) has been implemented successfully.