Low-Voltage Ride-Through Solution for a grid connected DFIG Wind Turbine using Series Voltage Compensation

This paper presents a new solution for doubly fed induction generators to stay connected to the grid at the time of faults and sags. To create the required flux to keep the rotor side converter current below its transient rating the stator voltage is increased to certain level at the time of faults. In order to maintain that one we are injecting the required voltage in series to the stator side line by designing a series compensator. The series converter will examine the grid voltages and provides compensation accordingly to keep DFIG to continue its operation. . Since the turbine and converter stay connected, the synchronization of operation remains established during and after the fault and normal operation can be resumed immediately after the fault is cleared. . To keep the current at its minimum, a control strategy has been developed to keep the injected voltage and line voltage in phase during and after the fault. The energy efficiency of wind turbine systems equipped with doubly-fed induction generators are compared to other wind turbine generator systems.

KEY WORDS: low-voltage ride-through, DFIG, injected voltage