Improved control strategy of three-phase four-wire inverters using sliding mode input-ouput feedback linearization under unbalanced and nonlinear load conditions

Abstract

In this paper, a novel nonlinear control scheme is proposed to regulate the three-phase output line-to-neutral voltages of a three-phase split-capacitor inverter as an AC power supplies. First, the nonlinear model of the system consisting of LC filter is obtained in the d-q-0 synchronous reference frame. Then, the input-output feedback linearization is applied through the sliding mode approach which avoids the complex calculations and simplifies further the controller structure. Also, a low-pass filter is employed for the sliding mode control to reduce the chattering of the load variations to acceptable levels without affecting the performance of the controller. The validity of the control method has been verified by simulation results.