Optimal power generation control of wind turbines based on dynamically updated torque limit values

Abstract

Summary For large‐scale commercialized wind turbines, using the speed‐torque lookup table is a traditional strategy to achieve optimum tip‐speed ratio tracking. Due to the constraint of the minimum grid‐connected generator speed and the rated generator speed, the strategy can only use the slashes to describe these 2 transition zones. This affects the smoothness of the output power, shrinks the optimum tip‐speed range, and loses the generating energy. Based on an analysis of the nonlinear aerodynamics of the wind turbine, this paper presents a strategy of realizing optimal power generation control that dynamically updates the output torque limit value of the controller. The strategy solves the problems of unmeasurable wind speed and inability to track wind speed and achieves the target of maximum wind energy capture below rated wind speed. Simulation and field test results proved the correctness of the algorithm.

An optimal power‐decoupling control strategy between torque and pitch controllers for variable‐speed pitch‐regulated wind turbines

“…The purpose of the torque controller is to maximize the energy capture by delivering torque demand to the converter system. At low wind speeds, the generator speed is regulated with a torque algorithm that varies the generator‐torque demand to maximize the energy capture of the turbine . The torque controller can usually be implemented using a lookup table or PI regulator; the generator speed is used as the reference input, and the required generator torque acts as the output demand.…”

An efficient sensorless approach for energy conversion enhancement and damping response improvement in permanent magnet synchronous generator (PMSG) based wind turbines

“…The indirect power controller deals with obtaining the maximum aerodynamic power, and the direct power controller focuses on realizing the maximum electric power. Lou et al detects the nonlinear relationship between the energy conversion efficiency of a variable speed WT and wind speed, rotor speed, and pitch angle, and then proposes a strategy of realizing the optimal power generation control of a WT. Also, Bayat and Bahmani deals with the problem of power regulation and control of WTs using an output feedback scheme formulated as a well‐defined linear matrix inequality problem.…”