Application of Real-Time Rotor Current Measurements Using Bluetooth Wireless Technology in Study of the Brushless Doubly-Fed (Induction) Machine (BDFM)

The brushless doubly-fed machine (BDFM) shows commercial promise as a variable speed drive or generator. However, for this promise to be realised, the design of the machine must be improved. Accurate machine modelling is therefore required for design optimisation. The measurement of rotor bar currents is of considerable benefit in the process of developing an accurate machine model. The authors present a system of measuring rotor bar currents in real time using a Rogowski coil to transduce the signal and recently available Bluetooth technology to transmit the data from the moving rotor to a standard PC. A coupled-circuit model has been developed for the BDFM to predict its dynamic and stead-state performance. The model has been verified using the proposed measurement system. The experiments were carried out on a frame size 180 BDFM with a nested-loop rotor design