Vibration mitigation for wind turbines using electromagnetic shunt damper with negative impedance converter

Recognizing the electromagnetic shunt damper (EMSD) as a vibration control device that enables versatile mechanical behavior through appropriate shunt-circuit configurations, this study investigates its application to a 10 MW steel-concrete hybrid wind turbine (HWT). An enhanced EMSD, namely, N-EMSD, composed of an electromagnetic damper (EMD), a negative impedance converter (NIC), and an RLC circuit, is employed to replace the damping unit of a conventional tuned mass damper (TMD) and to construct the analyzed mass-EMSD. First, the merits of introducing NIC for N-EMSD and the detailed mechanism of N-EMSD were presented. The NIC renders theoretically feasible the realization of versatile mechanical behaviors of the EMSD. Circuit tests for the NIC were conducted. Subsequently, a Simulink-OpenFAST coupled model is established, covering the excitation, HWT structural dynamics, and the N-EMSD with electromechanical dynamics. The control performance of the mass-EMSD is evaluated using the coupled model in the normal operation mode. The control device is applied in the side-to-side direction of the HWT. The mass-EMSD achieves promising control effects, with reduction ratios of tens of percent in the standard deviation of tower-top side-to-side displacement and the associated root-mean-square acceleration, slightly outperforming those of the TMD. In addition, the power generation and pitch control effects are analyzed in the modeling; the introduction of control devices has limited effects on these aspects. These results demonstrate that the proposed mass-EMSD is an effective control device for HWT, shedding light on the development of electromagnetic-oriented vibration control strategies for WTs.