Study on MPPT Control of the Single-stage Grid-connected Photovoltaic System

The fuzzy control can react to the environment change quickly and keep the photovoltaic system work on its maximum power point all the time. However, the limitation in the fuzzy control itself and the characteristic of self-optimization lead to serious concussion of the system around the maximum power point. Whereas the PID control method is effective in the elimination of concussion and is easy to be realized. To tackle the problem, the fuzzy parameter self-tuning PID control method is adopted in the paper to achieve the MPPT control of PV system. The method can effectively eliminate the concussion around the maximum power point and improve the stability of the system; and achieve grid-connected operation with a high power factor in combination with the harmonic elimination PWM control of inverter. Simulation results show that the scheme has merits of simple structure, high power factor and reliable operation, etc. and is worthwhile to be popularized.