Analysis of C-Dump Converter for SRM Drives

Electric motors has been taking significant roles in electric and hybrid electric vehicles. One of these is switched reluctance motor. Torque of a switched reluctance motor is affected by its stator winding current during negative slope of phase inductance. The use of higher negative voltage during demagnetizing mode is required to turn off the current faster. Asymmetric converter is capable to reverse the polarity of DC source to do fast turning off the current but this converter requires more number of static switches. This will lead to greater losses, high cost and is not suitable for low voltage applications. A converter with less amount of switches is more preferable due to its cost factor and voltage drop. C-dump based converter topology can be implemented to meet such requirements. This paper describes detailed analysis of a standard C-dump converter involves the operating modes, how capacitor voltage affects the current turning off and control strategy. Finally, simulation works were done to verify the analysis. Due to the results, the use of higher capacitor voltage leads to faster demagnetizing process.