Modeling and Research of Three-Phase Inverter Powering Nonlinear Load

Three-phase inverter has been widely applied in various applications, and lots of control schemes are investigated for the inverter powering nonlinear load, aiming to achieve favorable performance. However, the model currently proposed for inverter is based on linear load, which is not suitable for condition with nonlinear load. In this paper, a novel modeling method for three-phase inverter powering nonlinear load is proposed. Then, the mathematical derivation and performance analysis of the proposed model are presented in detail. Based on the proposed model, a control scheme is further presented, incorporating PI control and capacitor current feedback. In addtion, the second-order system damping theory and phase-plane analysis method are well developed to describe the steady-state and dynamic performance of the proposed model and control scheme. Compared with conventional dual-loop control, low THD of the ouput voltage could be acheived by means of the proposed scheme, which is perfectly validated by the simulation results.