Research on Zero-Voltage Ride Through Control Strategy of Doubly Fed Wind Turbine

Abstract

With the rapid increase in the proportion of the installed wind power capacity in the total grid capacity, the state has put forward higher and higher requirements for wind power integration into the grid, among which the most difficult requirement is the zero-voltage ride through (ZVRT) capability of the wind turbine. When the voltage drops deeply, a series of transient processes, such as serious overvoltage, overcurrent, or speed rise, will occur in the motor, which will seriously endanger the safe operation of the wind turbine itself and its control system, and cause large-scale off-grid accident of wind generator. Therefore, it is of great significance to improve the uninterrupted operation ability of the wind turbine. Doubly fed induction generator (DFIG) can achieve the best wind energy tracking control in a wide range of wind speed and has the advantage of flexible power regulation. It is widely used at present, but it is sensitive to the grid voltage. In the current study, the DFIG is taken as the research object. The transient process of the DFIG during a fault is analyzed in detail. The mechanism of the rotor overcurrent and DC bus overvoltage of the DFIG during fault is studied. Additionally, the simulation model is built in DIgSILENT. The active crowbar hardware protection circuit is put into the rotor side of the wind turbine, and the extended state observer and terminal sliding mode control are added to the grid side converter control. Through the cooperative control technology, the rotor overcurrent and DC bus overvoltage can be suppressed to realize the zero-voltage ride-through of the doubly fed wind turbine, and ensure the safe and stable operation of the wind farm. Finally, the simulation results are presented to verify the theoretical analysis and the proposed control strategy.

Zero-Voltage Ride-Through Scheme of PMSG Wind Power System Based on NLESO and GFTSMC

“…ZVRT can be considered to be an extreme case of LVRT [5]. It requires that the wind turbine continue operating when the grid voltage drops to zero, which puts further requirements on the fault ride through capability of the wind power system [6]. Many countries have incorporated the requirements of ZVRT into their grid codes.…”

Application and Comparison of a Modified Protection Scheme Utilizing a Proportional–Integral Controller with a Conventional Design to Enhance Doubly Fed Induction Generator Wind Farm Operations during a Balanced Voltage Dip

“…The protection device that is most commonly used is the "crowbar with DC-chopper"-type resistor. The crowbar consists of a unique combination of resistor banks [26,27] that are placed in series via an IGBT switch with the rotor windings, and the DC-chopper consists of unique resistors placed in parallel through an IGBT switch with To ensure continuous network connectivity during disturbances, the system should incorporate fault ride-through (FRT) techniques that enable it to overcome faults. Many different FRTs in the literature have been proposed and can be classified as follows: integrating an additional device for protection [12][13][14][15][16][17][18][19][20] and implementing a reactive power supply [21][22][23][24][25].…”

“…The protection device that is most commonly used is the "crowbar with DC-chopper"-type resistor. The crowbar consists of a unique combination of resistor banks [26,27] that are placed in series via an IGBT switch with the rotor windings, and the DC-chopper consists of unique resistors placed in parallel through an IGBT switch with the capacitor of the DC-link. In the course of the fault, the RSC is uncoupled from a rotor, and collector rings are commutated toward the crowbar resistors.…”