An Implementation on 3ph Inverter for Distributed Generation System: Adaptive Voltage Control and P-Q Control of the System

This paper reviews an adaptive control method of three-phase voltage source (VSI) inverters for stand-alone distributed generation systems (DGSs). The voltage controller includes two control terms: an adaptive compensating term and a stabilizing term. The adaptive compensating control term is combines an adaption control term and a state feedback control term and constructed to avoid directly calculating the time derivatives of state variables. Meanwhile, the stabilizing control term is designed to asymptotically stabilize the error dynamics of the system. Also, a fourth-order optimal load current observer is proposed to reduce the number of current sensors and enhance the system reliability and cost effectiveness. The stability of the proposed voltage controller and the proposed load current observer is fully proven by using Lyapunov theory. The proposed control system can establish good voltage regulation such as fast dynamic response, small steady-state error, and low total harmonic distortion (THD) under sudden load change, unbalanced load, and nonlinear load. Finally, the validity of the proposed control strategy is verified through simulations and experiments on a prototype DGS test bed with a DSP. For a comparative study, the control scheme of feedback linearization for multi-input and multi output is implemented, and its results are presented in this paper.