Generalised theory of the brushless doubly-fed machine. 2. Model verification and performance

The paper compares the performance predictions made using a new model of the brushless doubly-fed machine with measurements made on a laboratory test machine. The agreement between measurement and prediction is shown to be very good. The synchronous behaviour of the machine is shown to be very similar to that of a DC-excited synchronous machine, with the shaft torque determining the input power and the power factor being controlled by the voltage applied to one of the windings. The effect of magnetic saturation is discussed, and operating limits based on maximum flux and current limits are investigated.