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Analytical models are the key tools in the model‐based control design of electric drives. The inductances together with the stator resistance are the fundamental parameters of these models. In this study three methods to determine the inductances of the decoupled d–q model of double‐star permanent‐magnet (PM) synchronous machines are studied. These methods have commonly been used to determine the inductances of conventional three‐phase PM machines. Two of the evaluated methods are based on the phase‐variable inductance waveforms and flux linkages and are thus analysed with finite‐element analyses only. The third method, based on the analytical stator voltage equations, can be applied straightforwardly with the real drive system supplied with voltage‐source inverters (VSIs). This method requires only the knowledge of the rotor position and the existing current measurements of the VSIs that are used for the current control. Experimental results are provided to verify the applicability of the voltage‐equation‐based method to determine the inductances. On the average, the presented methods provide similar values, but also some discrepancies between the obtained values can be observed. The measured inductance parameters are validated using model‐based closed‐loop controllers. [ABSTRACT FROM AUTHOR]

This paper describes a d– q transformation to be applied to double-star permanent-magnet synchronous machines with interior magnets. The d– q model consists of two d–q reference frames decoupled with respect to each other and applies to a generic angular displacement between the winding sets. The decoupled d–q model simplifies the analysis of the machine behavior and the drive control implementation. Machine parameters are determined by a sequence of finite-element (FE) analyses. The effectiveness of the proposed modeling method is verified by a comparison with the results related to measurements on a test machine and FE simulations. It was assumed that the mutual inductances between the two winding sets can be represented with two coefficients. Although such an assumption inevitably leads to inaccuracy in the machine model, the simulation results with the proposed d–q model agree remarkably well with the experimental results and FE simulations. [ABSTRACT FROM PUBLISHER]