Sliding mode pulse width modulation for voltage control of a Voltage Source Inverter

In this paper, a Sliding Mode Control (SMC) based Pulse Width Modulation (PWM) method is proposed for the voltage control of a three-phase Voltage Source Inverter (VSI). This variable frequency PWM method is designed such that the average of the outputs, i.e, the three-phase voltage of VSI and the neutral point voltage of a star connected load, track the desired references. A suitable mathematical model of VSI is derived. Because of the control objective which is the tracking of a desired reference by the average of discontinuous output, some integral sliding surfaces are defined. Based on the mathematical model and the defined sliding surfaces, a controller is designed to generate suitable signals for the gates of the VSI switches. Simulation results verify the satisfactory performance of the proposed method.