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Comparison of oscillation damping capability in three power control strategies for PMSG-based WECS



With the aid of small signal analysis and digital simulations, this paper compares the mechanical and power oscillation damping performances of three power control strategies for the multi-pole permanent magnetic synchronous generator (PMSG)-based direct driven wind energy conversion system (WECS). Maximal power point tracking (MPPT) control implemented in the generator side has inherent abilities on the oscillation damping. For the smoothed or constant power requirements, power oscillations are hard to damp, and additional active damping controller is required. Active damping can be achieved with power control on the generator or grid side and DC link voltage control on the generator side. With additional compensator in the power or DC link voltage control loop, a damping torque is produced to suppress the oscillations. An improved control structure, which has inherent oscillation damping capability, is proposed for the power control of WECS. Combined with different power control strategies, this structure can be applied to achieve different power outputs. The validation of the proposed control structure is verified by the simulations. Copyright © 2010 John Wiley & Sons, Ltd.