Abstract :
This paper presents a stand-alone photovoltaic system with Ni-MH battery serving as its energy storage element. The proposed system is composed of a boost converter, a bidirectional dc-dc converter and a single-phase dc-ac inverter. The boost converter is used to track the maximum power point of the solar panel whereas the bidirectional dc-dc converter is applied to maintain the dc-link voltage stable through charging or discharging the battery, and the inverter is used to supply ac loads in the isolated system. Control system design for the three different types of converters are described based on the system mathematical models and perturbation and observation method is used as MPPT control algorithm. Nonlinear load is considered to verify the universality and robustness of the control scheme. Moreover, dc loads can also be directly connected to the dc bus. Using MATLAB SIMULINK, the simulation model of the isolated PV system with the proposed control schemes is created, and the performance of the coordinated control strategies is confirmed.
