A novel converter topology for switched reluctance motor drives

A new converter topology for switched reluctance motor drives is proposed in this paper. It has the advantages of minimum number of power switching devices, same voltage rating for all of them, variable DC link voltage for application to the motor windings to reduce the switching frequency of the phase switches and hence the switching and core losses but higher and fixed DC link voltage for faster commutation of phase currents. The converter provides a full four quadrant operation with the advantageous and important control features of independent energization and commutation of each phase winding. Further it requires no snubbing for its phase switches and only a minimum set of logic power supplies as all the phase switches have the same common. It has the disadvantages of requiring a chopper section with its attendant passive filter for reducing the DC link voltage for motor winding application. It is found that it is superior to many other (m+1) switch configurations, where m is the number of machine phases, due to the advantages described earlier. The principle of operation, modes of operation, design of the chopper stage, performance constraints and evaluation of the commutation time and rise in the source capacitor voltage for design of the machine side converter, merits and demerits of the proposed converter topology for the switched reluctance motor drives are systematically developed in this paper.