Evaluation of Incremental Conductance Maximum Power Point Tracking Method for Photovoltaic Systems

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The maximum power point tracking (MPPT) controller with incremental conductance method is implemented using the Stateflow toolbox from Simulink. Stateflow chart is a very powerful tool that graphically allows to do state machines and logical event based controllers and can be created states and transitions. All of these transitions are based on decision based on measurement of system. When the program running can be visualized how is making the decision and how the system is moving from one state to another. The simulation results are presented and analyzed to validate that the proposed simulation model is effective for the MPPT control of photovoltaic (PV) systems at rapidly changing irradiation condition. The simulation was first run with the MPPT controller using the incremental conductance algorithm. As the irradiance is changing, the MPPT controller makes the power coming out of the PV array to be kept at maximum. Then, the simulation was run without the MPPT controller (the PV array was directly connected to the load) under the same irradiance level. Therefore, the output power of PV array is smaller than in previous case. Finally, the incremental conductance MPPT method was tested under fast changing irradiance level. The step change response of power for the PV array and dc/dc buck converter is analyzed considering two cases of step size of duty cycle of MPPT controller.

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