Current feed optimization for the switched permanent magnet reluctance machine

In this paper the driving principle of a special permanent magnet excited synchronous machine, in the following called the switched permanent magnet reluctance machine (SPM), is discussed. The SPM is a promising variant of the brushless DC motor concerning design and robustness. The mechanical construction is similar to the switched reluctance motor (SRM), whereas the characteristics relate to the brushless DC motor. The linear relation between torque and current results from the fact that the SPM uses permanent magnetic (PM) energy and is leading to the comparison with the BLDC. Due to the fact that the resulting flux in one coil depends on all inductances (PM, mutual and self) the question for an effective current feed method came up. With the help of an electromechanical model an optimization process has been done and is presented. Furthermore with the help of the model the resulting torque of the SPM can be split into the different parts. Hence, the mutual dependencies of torque, power factor, efficiency and current can be explored.