Analytical Determination of Model Parameters of Multiphase YASA Machines

This paper addresses the determination of the electromagnetic parameters of multiphase yokeless and segmented armature (YASA) electric machines. Initially, we briefly review dynamic models useful for predicting the transient behavior of three-phase and five-phase permanent magnet (PM) synchronous machines. Then, analytical expressions are derived specifically for YASA machines, which allow the determination of the following parameters from the models: (i) phase resistance, (ii) synchronous inductance, and (iii) PM-flux linkage. To validate the parameters, we use numerical results obtained with the finite element method and experimental results concerning a YASA prototype under two different winding connections, with one connection defining three phases ( \(m = 3\) $m=3$ ) and the other five phases ( \(m = 5\) $m=5$ ). The numerical and experimental results show that the expressions proposed here provide a good estimate for the electromagnetic parameters for both phase numbers. Finally, to test and validate the parameters analytically obtained for \(m = 5\) $m=5$ , they are used in a transient dq-model of an existing five-phase YASA machine running under field-oriented control.