Soft-start control strategy for the three-phase grid-connected inverter with LCL filter
To solve the start-up inrush current existing in the three-phase grid-connected inverter, a soft-start control strategy for the three-phase grid-connected inverter with LCL filter is proposed. The analysis of start-up inrush current is illustrated in detail. The capacitor current of the LCL filter is used to detect the closure of the grid-connected switch, so the closing time of the grid-connected switch does not need to be known. The detailed procedure and flowchart of the proposed soft-start control method are provided. Finally, experimental results of a LCL-type three-phase grid-connected inverter verify the theoretical analysis. The control strategy is easy to implement. The start-up inrush current does not exist in the grid-connected inverter.