Multi-Time Scale Optimal Control of Voltage Fluctuation at PV Grids Considering Load Changes

In order to improve the stability of photovoltaic grid voltage output, a multi time scale optimal control method for photovoltaic grid voltage fluctuation based on load change stability adjustment is proposed. According to the voltage feedback correction of the oscillation information of the absorption ripple of the passive components in the DC bus voltage chain, the LC resonant circuit series connection method is used to achieve dynamic feedback adjustment of the voltage parameters of the photovoltaic grid connection points. According to the cut-off frequency of the voltage outer loop or the current inner loop, the gain of the voltage and current of the photovoltaic grid connection points is improved. The PI controller cascade quasi resonant method is used to dynamically adjust the time slot of the grid load changes, By filtering out the secondary ripple current using a peak suppression method, the multi time scale optimal control of voltage fluctuations during sudden load changes is achieved. The experimental results show that this method has good tuning and amplitude modulation capabilities, strong anti resonance ability, and strong power grid frequency ripple suppression ability for photovoltaic grid voltage fluctuation control, improving the stability of photovoltaic grid voltage output.