Digital Mirroring System for DFIG Wind Turbine Generator with Parallel Converters

With the increasing power rating of wind turbine system, parallel converters are now widely used in high-power doubly-fed induction generators (DFIG) to improve reliability and capacity, which are also beneficial to converter modularized production. Additionally, most parallel converter DFIG generators are built in off-line simulation software, these simulations have obvious disadvantages for its low calculation speed and accuracy. To conquer this limitation, this paper designs a novel digital mirroring system for DFIG wind turbine generators with parallel power converters to increase its capacity as well as simulation speed, electrical models and aerodynamic models are built in real-time digital simulator (RTDS) and GH Bladed respectively, while distributed DSP is functioned as hardware controller. Real-time simulation ability is finally verified on this digital mirroring system in various working conditions, including steady state operation, grid fault operation, primary frequency regulation as well as virtual inertia response, experiment results show that the designed digital mirroring system is effective in conducting real-time parallel converter DFIG wind turbine generator system.