Determination of dq Model Inductances in PM Generators

Two axis theory is generally used to model and analyze permanent magnet machine performance. Motor and generator parameters such as the d- and q-axis inductances are very important for the controller design. Nevertheless, traditional methods of determining parameters by testing is not viable if the field current cannot be controlled. Using power measurements and load angle computations, this study aims to determine the d-q inductances of a PM generator with Lq greater than Ld. Furthermore, the method will be applied to a conventional synchronous generator with constant field current and Ld greater than Lq. The results will be compared with those obtained by methods already well established.