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In this paper, the internal model control (IMC) method is applied to ac machine current control. Permanent magnet synchronous machines and induction machines are considered. The result is synchronous-frame proportional integral (PI) or PI-type controllers, the parameters (gain and integration time) of which are expressed directly in certain machine parameters and the desired closed-loop bandwidth. This simplifies the controller design procedure, eliminating or reducing the need for trial-and-error steps, and is the main purpose for using IMC. Index Terms - Current control, internal model control, inverterfed machines.

The interest in permanent-magnet synchronous motors (PMSMs) is increasing in a wide area of applications. Since most PMSMs will operate without a shaft sensor in the future, valuable information for experimental determination 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 load angle [Delta] is determined from the load test by means of a new analytical method. In this way, no separate measurement of the load angle is required. The method is especially suitable for line-start PMSMs which normally operate with negative d-axis current and, therefore, are not saturated in the d-axis flux paths. Moreover, the method is very simple to carry out for any laboratory technician, since the only tests that have to be made are standard tests which are made on standard induction motors on a regular basis. Index Terms--dq model, permanent-magnet machine, power factor, synchronous reactances.