A Sliding Mode Control for a Grid-Connected Three-Phase Voltage Source Inverter Based on a New Reference Frame

This paper presents a switching strategy for a grid-connected voltage source inverter (VSI) using sliding mode control (SMC). The conventional SMC suffers from sliding losses due to the cross-coupling among controllers by the neutral point voltage expression. This issue can be addressed by using the switching technique to obtain the voltage and currents in a new reference frame through a non-linear transformation. In this frame, a decoupled non-linear model of the VSI is derived, and two sliding mode controllers are designed using hysteresis band comparators. The switching strategy not only avoids sliding losses but also increases the control range of the converter by introducing a third harmonic by the control signal. Simulation results using Matlab Simulink are provided to validate the robustness of the proposed controller.