An Improved Grid-Forming Control Strategy of Energy Storage System for Enhancing Low-Voltage Ride Through Capability

Under the “double carbon” target, the Grid-forming (GFM) storage stations have been used rapidly to stabilize the intermittent and unstable output power from renewable energy resources. However, the recent studies on the control strategies for these storage stations are paying main attention to simulating the synchronous generation characteristics. Once the grid fault occurs, the existing control strategies of the GFM inverter have the overcurrent problems and the inaccurate reactive power supply. In order to solve the above problems, an improved GFM control strategy is proposed in order to enhance the low voltage ride through capability. Under the grid fault the Q-v droop control is deactivated for ensuring the reactive power control accuracy. And the reactive power reference of the virtual synchronous generator control is reset based on the low voltage ride through requirement. Meanwhile, an active power limiter is added into the virtual synchronous generator control in order to limit the current through the inverter. Finally, the tested 10 kW grid-forming energy storage station is built based on PSCAD/EMTDC to verify the effectiveness of the proposed strategy.