Energy Efficient C-Dump Converter with Simple Control Strategy for SRM Drive

A switched reluctance motor (SRM) has good prospects in electric drive for its beneficial features. To develop torque in SRM, its stator winding must be excited during positive slope of the stator inductance and then turned it off as soon as possible using negative voltage when the aligned position between the rotor and stator is passed. An asymmetric converter is able to achieve such processes through two switches connected to the phase winding although it results in greater voltage drop. To reduce the number of switches, a capacitor is used in C-dump converters to provide negative voltage to degrade the phase current faster during commutation. In this paper, an energy efficient C-dump converter without inductor is designed with simple control strategy. The voltage on the capacitor is used to commutate and to turn on the phase current in the beginning of the excitation for better efficiency. To verify the analysis, simulation and experimental works were done. They show the proposed control strategy is capable to control the capacitor voltage that finally affects the motor speed.