Sliding mode control of a three-phase inverter

This chapter proposes a sliding mode approach (SMA) for voltage source inverter (VSI) to regulate the powers injected into the grid. A VSI is employed to connect the wind power system (WPS) to the electrical network system (ENS) and to process the energy generated by this system. The SMA is used for both the three-phase inverter and the rectifier. The inverter is commanded to control the delivered power to the ENS and to sustain invariable the voltage of the DC-link, whereas the rectifier is controlled to guarantee the maximum power point (MPP) for the wind turbine (WT). So, the active current reference is produced via an external loop that has the function of keeping constant voltage of DC-link, but the reactive current reference is fixed to zero to guarantee unity power factor (UPF). The stability of the regulators is achieved via Lyapunov analysis. Simulation results confirm the success of the presented approach and show it can work consistently under diverse conditions. Also, it reduces the impact of short-circuit and fluctuations of voltage on the grid. The comparative results and analysis for the presented SMA strategy and the conventional vector control (VC) are presented for different grid voltage conditions to indicate the excellent performances of SMA method including smoother transient responses and less fluctuation under fault conditions.