With increasing global energy demand, extracting higher output power from in-service wind turbines is a cost-effective option for wind farm operators. This paper presents a novel strategy for Enhanced Power Recovery through Overrating (EPRO) of a permanent magnet synchronous generator (PMSG), which increases generator currents above nominal rating in the turbine’s constant power operating region. Innovative temperature sensing in the stator windings protects against overheating and field weakening control is integrated with the turbine pitch control to obtain higher current, whilst remaining within the original inverter voltage limit. Operation in the maximum power point tracking region is unchanged. A custom integrated electro-thermal model of the wind generator is used at the design stage to identify hotspots and ensure magnet and winding temperatures are not exceeded. A grid-connected, kW-scale test rig with built-in Fibre Bragg temperature sensors provides experimental validation. The EPRO strategy is compared for different dynamic wind speed profiles, with good agreement between simulation and experiment. Laboratory results demonstrate a sustained increase in generated power of up to 26% above conventional operation, whilst remaining 30°C below the insulation temperature constraint. At MW-scale, the power increase would depend on the PMSG thermal design, the required upgrade in grid interface hardware, and availability of the wind resource.
Ghafoor et al. (Thu,) studied this question.