Two phase modeling, experimental characterization, and power converter with fast demagnetization for switched reluctance motor drives

Dynamic modeling of Switched Reluctance Machines (SRMs) is usually done on a per phase basis. However, since SRMs are used with more than one phase excited, a multi-phase excitation dynamic model that accounts for magnetic saturation is required for accurate performance prediction. The generalized modeling approach for nonlinear, multiply excited, electromechanical systems is simplified, and a two-phase excitation model for the SRM is derived. The SRM is experimentally characterized for flux linkage data needed for the model. The number of measurements required is reduced significantly by identifying spatial symmetry conditions. Experimental procedure to measure the data is presented. Samples of data measured are included with their implications. Simulation results from the dynamic model are correlated with experimentally measured results.; To a large extent, SRM operation depends on the power converter used. A generic SRM converter is derived from general desirable features. Using some guiding principles, most converter topologies can be derived from the generic converter. A dual dc rail converter topology—a modification of the classical converter with a buck-boost energy recovery scheme, is chosen for implementation. This converter has the feature of two voltage levels for demagnetization, one of which is higher than the energization voltage. This extends the torque capability at high speeds while reducing the motor rms current. Design of the energy recovery circuit and its associated controller are described. Simulation and experimental results are presented to illustrate converter operation. Computed and experimental results show extended torque capability of the machine.