DFIG wind turbine sliding mode control with exponential reaching law under variable wind speed

Increased penetration of wind energy systems has serious concerns on power system stability. In spite of several advantages, doubly fed induction generator (DFIG) based wind energy systems are very sensitive to grid disturbances. DFIG system with conventional vector control is not robust to disturbances as it is based on PI controllers. The objective of this paper is to design a new vector control that is robust to external disturbances. To achieve this, inner current loop of the conventional vector control is replaced with sliding mode control. In order to avoid chattering effect and achieve finite time convergence, the control gains are selected based on positive semi-definite barrier function. The proposed barrier function adaptive sliding mode (BFASMC) is evaluated by testing it on a benchmark multi-machine power system model under various operating conditions. The simulated results show that the proposed method is robust to various disturbances.

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Modified vector controlled DFIG wind energy system based on barrier function adaptive sliding mode control

Energy management and control strategy for a DFIG wind turbine/fuel cell hybrid system with super capacitor storage system

A new perturb and observe based higher order sliding mode MPPT control of wind turbines eliminating the rotor inertial effect

This study presents an overall sliding mode control scheme for stator power-current control, grid power-current control and dc-link voltage regulation to operate a doubly-fed induction generator (DFIG) based wind energy conversion system. At the generator rotor side, the stator power control is achieved through controlling the rotor currents. The rotor current state model is carried out from the stator and the rotor equations of the generator under the condition of stator voltage alignment. At the grid side, a cascade control loop is applied for the dc-link voltage regulation and the power transfer using grid and dc-link modelling. The structure of the sliding mode control law, combination of compensating, sliding and integral terms, enhances the tracking performance and the robustness to uncertainties. The proposed control strategy is validated using an experimental DFIG wind turbine system and the results are provided to demonstrate the capabilities of the proposed control system in tracking and control under different operating conditions and robustness to uncertainties.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/iet-rpg.2017.0313

Power-current controller based sliding mode control for DFIG-wind energy conversion system

Power optimisation is quite important for the doubly-fed induction generator (DFIG)-based variable speed wind turbine (VSWT) in the modern renewable power generation system. However, the VSWTs are generally non-linear and uncertain systems. This study proposes a super-twisting second-order sliding mode (SOSM) control scheme to maximise the wind energy capture of a DFIG-based VSWT system, and regulate the stator reactive power to follow the grid requirements. By regulating the generator rotor voltage, the designed SOSM controller makes the wind turbine rotor speed track the optimal speed to maximise the power generation, and controls the rotor current to follow the external reference to regulate the stator reactive power. A quadratic form Lyapunov function is adopted to determine the range of controller parameters and guarantee the finite time stability. Simulation results on a 1.5 MW DFIG-based VSWT demonstrate the effectiveness of the proposed control strategy.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/iet-rpg.2015.0403

Second-order sliding mode control for power optimisation of DFIG-based variable speed wind turbine

This paper proposes a super-twisting second order sliding mode control scheme to maximize the wind energy capture of a doubly fed induction generator based variable speed wind turbine (VSWT) system, and minimize the reactive power simultaneously Two second order sliding mode controllers are designed to achieve the control objectives, reduce mechanical stress and improve control accuracy By regulating the generator rotor voltage, one controller makes the wind turbine rotor speed track the optimal speed, which can maximize power generation The other maintains the rotor current at rated value to minimize the reactive power A quadratic form Lyapunov function is adopted to determine the range of controller parameters and guarantee the finite time stability Simulation results on a 15MW doubly fed induction generator (DFIG)-based variable speed wind turbine demonstrate the validity of the proposed control strategy

Xiangjie Liu

Papers

Second-order sliding mode control for power optimisation of DFIG-based variable speed wind turbine

Second-order Sliding Mode Control of DFIG Based Variable Speed Wind Turbine for Maximum Power Point Tracking