Novel approach for operation analysis of vector controlled adjustable speed synchronous machine drives

Novel approach for operation analysis of synchronous machine has been described. To draw the vector diagram under adjustable speed operation, the concept of normalized voltage was introduced. It is to divide the voltage value by angular frequency of the machine, and the vector diagram will keep its size unchanged for the whole speed range. Also, reactance drop locus and its accompanying yardstick circle for determining the current phase angle, in corresponding to the variation of the given armature current vector were deduced. Then, the operation of the whole adjustable speed range can be represented in single diagram. As accompanying matters, the methods for calculating the operating characteristics of maximum torque control and 100% power factor control were shown