Real-Time Emulation of Grid-Connected DFIG Wind Energy System with Model Validation from Sub-synchronous to Hyper-synchronous Operation under Unbalanced Conditions

Abstract

Previous work on real-time simulation of DFIGs have assumed that the generator model is valid over a wide range of operating speeds and for multiple grid voltage unbalances. However, this assumption has not been tested in the literature, which limits the accuracy of results obtained in both simulations and in hardware-in-the-loop (HIL) applications. To address this gap in the literature, this paper presents a preliminary model validation of the DFIG with iron losses and demonstrates the limitations of the model in accurately representing a physical DFIG machine under grid unbalanced operation. This paper implements all the required discrete models for real-time emulation of the DFIG on a field programmable gate array (FPGA), including: the dynamic model of the DFIG, rotor side converter (RSC), grid side converter (GSC), and aerodynamic and mechanical models. Also included are key implementation aspects of the hardware-testbed utilized for the model validation, which consists of a DFIG machine connected to a partial-scaled four-quadrant back-to-back power converter. The DFIG machine models utilized for this research are available to the public and can be accessed in a GitHub repository listed in the references.