The Application of Electric Spring in Grid-Connected Photovoltaic System

The characteristics of distributed photovoltaic system power generation system is intermittent and instability. Under the weak grid conditions, when the active power of the PV system injected into the grid is fluctuant, the voltage of supply feeder will increase or decrease, thus affecting the normal use of sensitive load. The electric spring can transfer the energy injected into the supply feeder to the wide-voltage load, which is in series with the ES, to ensure the voltage stability of the sensitive load in the system. In this paper, a grid-connected photovoltaic simulation model with electric spring is built in Matlab / simulink. The voltage waveforms on the ES and sensitive load is obtained under the condition of changing the active power injected into the supply feeder by the grid-connected photovoltaic system. Thought the analysis of the waveforms, we can find that the Electric spring is a kind of effective method to solve the voltage fluctuation of the supply feeder in the grid-connected PV system.