The maximum power point tracking technology of passivity-based photovoltaic grid-connected system

The output characteristics of photovoltaic (PV) cell is nonlinear, changing along with the change of external environment factors. In order to improve photovoltaic system´s work efficiency, it´s necessary to track the maximum power point. Considering single-stage three-phase photovoltaic grid-connected system as the research object, this paper analyzes the output characteristics of photovoltaic cell and operating principle of the system, and also designs passivity-based power controller. Meanwhile, the Incremental Conductance(INC) method based on power control is applied to the MPPT control, making the system response to the change of external environment quickly and accurately, so that the system is always working in the maximum power point. The Matlab/Simulink simulation results show that this method is feasible.