Research on Cascading Voltage Fault Ride-through Strategy for DFIG Based on Hybrid Energy Storage System

Abstract

At present, clean energy power generation technology is vigorously developing, and wind power generation technology is widely applied. Ensuring that the wind turbine operation is not off-grid has become critical. Currently, most of the studies on fault ride-through problems of doubly fed induction generators (DFIG) are single faults, i.e., low voltage ride through (LVRT) or high voltage ride through (HVRT), mostly ignoring the low and high voltage cascading fault. With the gradual increase of wind power penetration rate, how to ensure that the wind turbine operation is not off-grid has become critical. Currently, most of the studies on fault ride-through problems of doubly fed induction generator (DFIG) are single faults, i.e., low voltage ride through (LVRT) or high voltage ride through (HVRT), mostly ignoring the low and high voltage cascading fault This paper proposes a joint control strategy based on hybrid energy storage (HESS) to cope with the cascading fault ride-through requirement. During the fault period, the DFIG rotor side converter (RSC) works in the reactive power priority mode to provide reactive power support for the power grid. In view of the hysteresis of the traditional PI control of HESS, Model predictive control is used to improve. During the fault traversal process, the DC voltage of the fan is stable, the output waveform is smooth, and the support capacity is significantly improved. During the fault period, the DFIG rotor side converter (RSC) works in the reactive power priority mode to provide reactive power support for the power grid. In view of the hysteresis of the traditional PI control of HESS, Model predictive control is used to improve. Simulation results show that the proposed joint control strategy can effectively support grid voltage recovery and maintain stable DC bus voltage, effectively achieving DFIG low and high voltage continuous fault crossing. Simulation results show that the proposed joint control strategy can effectively support grid voltage recovery and maintain stable DC bus voltage, effectively