Three-Phase Current-Limiting Droop Controlled Inverters Operating in Parallel

Abstract

A new current-limiting droop controller is proposed in this paper for three-phase inverters operating in parallel. Droop control is employed to ensure the proportional power sharing between the parallel inverters while an inherent current-limiting property is achieved through the control design. The current limitation is mathematically proven using nonlinear analysis of the closed-loop system which leads to the boundedness of each inverter current under a threshold value at all times. Furthermore, small-signal analysis is performed to examine the closed-loop system stability of two parallel inverters equipped with the proposed controller. The example of two parallel inverters is further exploited to validate the proposed controller through Matlab/Simulink simulation results.