A coordinated control and management strategy of a wind energy conversion system for a universal low-voltage ride-through capability

The increased penetration level of wind power plants has brought new issues and challenges. One of them is the low-voltage ride-through (LVRT). This paper proposes a coordinated control and management strategy to improve the capability of a wind-energy conversion system (WECS) to fulfill the universal LVRT requirements. Moreover, it aims to exploit the system maximum capability in regard to its protection and to ensure an optimized power management. In fact, under grid fault, the machine-side converter (MSC) contributes to the DC-link voltage regulation by storing a percentage of the surplus power in the drive shaft inertia of the WECS. Meanwhile, the grid-side converter (GSC) injects a portion of active power and reactive power required to support the grid voltage recovery. In this condition, the DC-link voltage is controlled through batteries by a DC-DC converter and a braking chopper circuit. Whereas, in normal grid conditions, the DC-link is regulated via the GSC. The proposal supports the WECS to ride through severe low voltages and protects the WECS from excessive current, overvoltage, the PMSG from overspeed, and extends the batteries' lifespan. Simulation results show the effectiveness and the validity of the proposed coordinated control and management strategy.