Comparison of Test Methods for Characterisation of a Doubly-Fed Induction Machine

The doubly-fed induction machine is widely used in variable speed ac drives. Accurate characterisation of the machine is important to optimise its efficiency and functionality. A novel characterisation method using the series-coupling test approach has produced favourable results in characterising this machine. This paper reviews the series-coupling tests and compares their results with IEEE Standard 112. The conventional IEEE Standard 112, series-coupling and extended short-circuit testing procedures are used to characterise the machine. The various models obtained from these methods are validated by comparing the model predictions with the experimental torque- speed curve of the machine. The series-coupling test models perform best in predicting the machine performance. A sensitivity analysis of the test procedures is carried out to determine the influence errors in experimental measurements have on the respective models. Finally, the variation of parameters with applied test conditions in the series-coupling procedure is investigated.