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27 results on '"Chang, Yuanzhu"'

5. Control Solution to Over-Modulation of DFIG Converter for Asymmetrical Fault Ride Through

Author

Chang, Yuanzhu, Berger, Maxime, and Kocar, Ilhan

Abstract

This letter proposes a control solution to mitigate the problem of converter over-modulation in doubly fed induction generator (DFIG)-based wind turbine generators (WTGs). Overmodulation is a critical reason in failing to ride through asymmetrical faults and inject positive- and negative-sequence reactive currents (I1R and I2R) per grid code requirements. Analytical expressions are first proposed to independently calculate the transient, positive- and negative-sequence current components. The I2R injection factor is then optimized to mitigate the problem of steady-state over-modulation. The transient components are eliminated in the inner-loop control to mitigate the problem of transient over-modulation. The proposed control solution is validated with EMT-type simulations. The results show that the transient performance and the fault ride through (FRT) capability are significantly improved.

Published
2024
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11. Wind Farm Equivalent Model Based on Power Output Sensitivity of Wind Turbines

Author

Chi Yongning, Tang Haiyan, Tian Xinshou, Chang Yuanzhu, and Li Yan

Subjects
Wind power, business.industry, Astrophysics::High Energy Astrophysical Phenomena, Thermal power station, AC power, Grid, Turbine, Equivalent model, Physics::Space Physics, Astrophysics::Solar and Stellar Astrophysics, Environmental science, Power output, business, Physics::Atmospheric and Oceanic Physics, Computer Science::Distributed, Parallel, and Cluster Computing, Marine engineering, Voltage
Abstract

In general, a wind farm composed of a wind turbine can control the exchange of reactive power between its wind farm outlet and the grid, that is, the entire wind farm does not emit or consume reactive power. Therefore, the reactive power loss of the wind farm of the doubly-fed wind turbine is only the reactive load of the system. Compared with the wind farm of the asynchronous wind turbine, the reactive power consumption of the wind farm of the doubly-fed wind turbine becomes smaller, and the voltage stability is obvious. Better than asynchronous wind turbine wind farms, the reactive power voltage control ability of the grid is weaker than that of synchronous generators. Therefore, when a part of the wind power in the power grid replaces the thermal power generation, the voltage stability of the power grid will be reduced, and the degree of reduction will depend on the reactive power reserve of the thermal power unit in the power grid. In this paper, the wind turbine is connected to the power grid as the research object. According to the voltage characteristics analysis after the wind power is connected to the power grid, the electrical characteristics and its influence in the wind farm are studied. Based on this, the equivalence modeling of the wind farm is proposed.

Published
2019

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