Uninterruptible motor drives: a case study with switched reluctance motor drives

Uninterrupted operation of motor drives is of interest in many applications. To maintain uninterrupted operation of this motor drives during utility power failures, it is customary to install uninterruptible power supplies (UPS) and these may be on- or offline operated to provide continuous power supply to the process drives. This paper considers topologies which could incorporate the uninterruptible power supply feature into the drive system itself eliminating the need for a separate UPS resulting in immense cost savings in the process. The paper introduces the concept of uninterruptible motor drives (UMD), explores the various power topologies for their implementation and illustrates the concept with a switched reluctance motor drive. Key experimental results are provided from a laboratory prototype to answer questions regarding efficiency of operation of this UMD. VA ratings of the UMD vis-a-vis conventional drive systems are derived to allow the comparison of the cost involved in the UMD implementation