Determination of d and q reactances of permanent-magnet synchronous motorswithout measurements of the rotor position

The interest in permanent-magnet synchronous motors:(PMSMs) is increasing i n a wide area of applications. Since most PMSMs will operate without a shaf t sensor in the future, valuable: information for experimental determinatio n of machine parameters will be lost,In this paper, therefore, a method is presented where the induced EMF and the d-axis reactance are determined in a no-load test and the q-axis reactance is determined in a load test. The l oad angle delta is determined from the load test by means of a new analytic al method. In this way, no separate measurement of the load angle is requir ed. The method is especially suitable for line-start PMSMs which normally o perate with negative d-axis current and, therefore, are not saturated in th e d-axis flux paths. Moreover, the method is very simple to carry out for a ny laboratory technician, since the only tests that have to be made are sta ndard tests which are made on standard induction motors on a regular basis.