Unified reference frame dq model of the brushless doubly fed machine

Control of the brushless doubly fed machine (BDFM) based on traditional multiple reference frames is complex. To simplify the control scheme, a new and simpler derivation of the dq model of the BDFM is proposed, leading to a unified-reference-frame model. This way, a simple dq model can be established, which could be an interesting tool for control-synthesis tasks. In order to determine the unified reference dq model, restrictions related to BDFM operation, as well as the exact rotor-cage configuration, have been considered. The proposed model has been validated by several experimental results. The work could facilitate future research on improved BDFM field-oriented control strategies.