Improved Adaptive Robust Control for Low Voltage Ride-Through of Front-End Speed Regulation Wind Turbine

Abstract

This paper proposes a low voltage ride-through (LVRT) control method for the front-end speed regulation (FESR) wind turbine based on an improved adaptive robust control (IARC) to find the solution of the generator parameter variation by grid voltage dip and enhance the LVRT capability of the FESR. First, the FESR system mathematical models and the control objective of LVRT are analyzed. Then, in the improved adaptive robust controller, the Lyapunov function for three subsystems and the energy function of the system are constructed. The excitation control law and parameter replacement law of the system are obtained by the error compensation term and additional control variable. The method makes the energy function satisfy the dissipation inequalities to guarantee the stability and ability to suppress disturbance of the system. To verify the effectiveness of the proposed control method, the proposed IARC is compared with the predictive fuzzy PID (PFPID) by time-domain simulations under different fault conditions. The results show that the proposed IARC can not only realize the rapid regulation of reactive power and effective resistance to grid voltage fluctuations but also improve robustness and transient stability of the system and enhance the LVRT performance of the FESR during the grid voltage dip. INDEX TERMS Front-end speed regulation (FESR) wind turbine, grid voltage dip, low voltage ride-through, adaptive robust control.

Fractional-order Sliding Mode Control of Hybrid Drive Wind Turbine for Improving Low-voltage Ride-through Capacity

“…To investigate control strategies, various studies have shown that a third-order mathematical model of SG is sufficient to satisfy engineering demands considering the complexity of control law modeling. In this case, the model of an electrically excited SG is given by [26], [27]:…”

“…SG excitation control allows to flexibly adjust the output voltage and power, thus improving the transient and steadystate grid-connected operation performance of SRDM-based hybrid drive WTs. Recently, [25] and [26] synthesized an adaptive robust excitation controller for ensuring the voltage stability and reactive power carrying capacity of hybrid drive WTs. The nonlinear effects caused by the strong coupling in the transmission system were reduced by including additional error compensators, but the required accurate system parameters are difficult to obtain.…”

Self‐stabilising speed regulating differential mechanism for continuously variable speed wind power generation system

“…In recent years, Yin et al [19] summarised the current status as well as the future prospects of CVT‐based WTs and pointed out that the mechanical, hydraulic and hydro‐mechanical CVTs all have good potential to be effectively‐employed in high‐power WTs. Dong et al [20, 21] investigated the control methods of front‐end speed regulation WT to optimise the output power and to improve the system low‐voltage ride‐through capability. Lin et al [22] analysed the frequency regulation ability of their proposed converter‐free offshore hydrostatic WTs.…”

“…Speed regulating differential mechanism (SRDM), expected to be effective in regulating output frequency of SG and eliminating undesirable effects induced by fully-or partially-rated converters, possesses advantages for VSCF wind turbines (WTs) in terms of improving energy transmission efficiency and system operational reliability as well as reducing equipment manufacturing and maintenance costs [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]. Using the advanced technologies of mechanical transmission and servo control, SRDM can be adopted at the front-end of SG to get constant-frequency power regardless of the changing wind rotor speed.…”

Voltage Stability Analysis of Front-End Speed Controlled Wind Turbine Integrated into Regional Power Grid Based on Bifurcation Theory

“…e essential difference of the FSCWT is that it uses a hydraulic torque converter named WinDrive to regulate the speed of the generator at the frontend of the turbine [16], greatly improving the low voltage ride-through capability of the wind turbine and increasing the advantage of reactive power output [17]. At the same time, the EESG is directly coupled with the power grid, which can provide certain transient support for the system in case of failure or instability of the access system.…”