Calculation of position-dependent inductances of a permanent magnet synchronous machine with an external rotor by using voltage-driven finite element analyses

This paper discusses finite element analyses of a skewed permanent magnet synchronous machine (PMSM) with an external rotor regarding the magnetic saliency. Since the machine is fed from a voltage source inverter (VSI), a simulation as close as possible to the regular operational behavior is intended. Therefore, a voltage-driven finite element model with a strong circuit coupling excited with the time-dependent voltages according to the space vectors of the VSI will be applied. This approach directly allows for a comparison of the numerically obtained phase currents with those obtained from measurements. Afterwards, the inductance characteristics depending on the rotor position can be evaluated from the time-dependent phase currents in order to obtain the suitability for a sensorless control algorithm. Index Terms--Finite element analysis, inform method, permanent magnet synchronous machine (PMSM), sensorless control.