"Untersuchung einer geschalteten Reluktanzmaschine mit Permanentmagnet-Erregung im Stator"
Untersuchung einer geschalteten Reluktanzmaschine mit Permanentmagnet-Erregung im Stator
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The attractive force of a magnetic field on soft magnetic materials is one of the earliest findings in the discovery process of designing electromechanical energy converters. Especially the switched reluctance machine (SRM) with its extremely simple and robust rotor construction is in the focus of investigations again and again, in order to overcome the disadvantages of this machine type. In the field of magnetic bearings with soft-magnetic shafts and external stator- or radial windings, the introduction of a magnetic bias flux by the use of permanent magnets (PM) led to a substantial improvement in the operating behaviour. In order to apply this idea to the
SRM topologies, a number of boundary conditions have to be considered and observed. An important point is the minimization of the cogging-torque, but also the examination of the favourable stator and rotor tooth number combinations of the switched PM machine (SPM) is necessary. As a result mainly positive phenomena, such as the linearization of the current-torque relationship and other operating properties are investigated in this work by the means of FE simulations, the development of a transient machine model and in an analytical way. In doing so, it turns out that the consideration of the relative period durations for the induced voltage and the inductance is of particular importance for the calculation of a loss-optimized current waveform. In reference to the market's interest in low-cost drive systems also the possibilities for angular position sensing are examined. Due to the fact that the SPM is a machine with high inductances and induced voltages that depend highly to the rotor position both, stray field sensor-based as well as sensorless methods are used and verified in hardware. The measurements on comparable demonstrator machines with different current shapes show the validity of the individual machine models. The model data and current shapes were obtained beforehand by simulation and optimization.