The grid-connection inverter of photovoltaic self-synchronous voltage source can significantly improve the grid connected stability of the new energy generation system because it simulates the frequency and voltage control characteristics of the synchronous generator;its DC capacitor can support the active power difference between the AC and DC sides of the inverter under irradiation fluctuations,thereby suppressing DC voltage fluctuations,which is particularly important for the DC voltage stability of the inverter.To this end,a method for selecting DC capacitors for photovoltaic self-synchronous voltage sources taking into account irradiation fluctuations was proposed.Through the transient modeling of photovoltaic self-synchronous voltage source system,the relational model between irradiance and DC voltage was constructed,and on this basis,the selection method of DC capacitor was put forward.The proposed method can accurately predict and evaluate the DC voltage changes under irradiation fluctuations,effectively avoid DC undervoltage,and achieve DC voltage stability of photovoltaic self-synchronous voltage sources under irradiation fluctuations.The effectiveness of the proposed method was verified through numerical examples and simulations.
关键词
光伏并网发电/可再生能源/自同步电压源/辐照波动/直流电容选型
Key words
photovoltaic(PV)grid-connection power generation/renewable energy/self-synchronous voltage source/irradiation fluctuation/DC capacitor selection
维普
万方数据