Three-phase grid-connected photovoltaic system with maximum power point tracking technique based on voltage-oriented control and using sliding mode controller

Abstract

This paper presents a Matlab/Simulink model of grid connected photovoltaic (PV) system, including a PV array, a maximum power point tracking boost converter and a grid interactive, a control system. A space vector pulse width modulation (SVPWM) has been widely applied in the current control of three-phase voltage source inverters (VSI). The proposed system consists of two main controllers: a boost converter and a grid interactive voltage source inverter. The boost converter is used to regulate the PV voltage and track the MPP of PV array. A perturbation and observation (P&O) is used as MPPT method and it determines the system operation point according of rapidly changing atmospheric conditions. A cascaded control structure with an outer dc link voltage control loop and an inner current control loop is used. The currents are controlled in a synchronous orthogonal d, q frame using a decoupled feedback control. The reference current of proportional-integral (PI) d-axis controller is extracted from the dc-side voltage regulator by applying the energy balancing control. Furthermore, in order to achieve a unity power factor, the q-axis reference is set to zero. The SMC proposed in this paper, to control of current uses the integral sliding mode. Furthermore, classical controls PI compared with the SMC. The results show that the SMC technique is more suitable than that classical control (PI).