Abstract:

The bus voltage stability of photovoltaic grid-connected converters is critical to the safe operation of power systems. Aiming at the problems of slow response and insufficient immunity of photovoltaic grid-connected converters under disturbances such as light and temperature, a fuzzy active immunity voltage stabilization control strategy is proposed. This strategy employs an extended state observer to estimate system disturbances and actively compensate for them, and combines the fuzzy clustering algorithm to achieve adaptive setting of control parameters. It integrates the offline learning of fuzzy clustering with the online compensation of active disturbance cancellation control. The double closed-loop structure of the voltage outer loop proportional integral(PI) control and the current inner loop active disturbance rejection control(ADRC) is adopted to achieve precise and stable bus voltage. The simulation results show that the bus voltage fluctuation is controlled within 8.3V, the grid-connected current total harmonic distortion(THD) is 2.1%, and the settling time is 1.5 s. All indicators are significantly better than the traditional methods, providing an effective guarantee for the stable operation of the photovoltaic system.

Key words: photovoltaic grid-connected converter, active disturbance rejection control, fuzzy clustering algorithm, double closed-loop control, voltage stability