Operation and control of switched reluctance generator in single-pulse mode

Abstract

In the present work, a control approach is proposed for the switched reluctance generator (SRG) from a novel, induced EMF perspective. When the SRG operates at high speed, it must be operated in single-pulse mode owing to the insufficient dc-bus voltage. Currents in the phase windings and the switches, in single-pulse mode, exhibit peaky nature. The magnitude of the peak current can be significantly high, and hence, it must be limited to protect the switches. The proposed control scheme ensures that the winding current is maintained to the rated capabilities of the converter switches to make sure that they are fully utilized without getting damaged. To achieve this objective, a fictitious circuit model is developed in this thesis. This model approximately gives the same rise of quantities in the actual circuit without knowing the instantaneous values of the actual quantities. Elements of this developed model are known from the typical waveshapes of the phase currents. The average induced EMF comes into this circuit as a voltage source. The value of this voltage source is known from the induced EMF coefficient curves that can be easily obtained from the machine magnetization characteristics. The excitation parameters for the control of the SRG are calculated using the developed fictitious model. Finally, a controller is developed which implements the developed strategy. The excitation commands given by this controller are tested on the simulation and experimental platform for an 8/6 pole, 4-phase SRG. The details of the simulation and experimental setup are also presented here.