Reliability Assessment of Motor Drives

Electric motor drives have seen widespread adoption in many applications. Motor drives reliability has become a driving factor for potential customers whose process up time and power availability are crucial to their business success. Reliability is therefore a key driver in power circuit design for these applications. Two commonly used approaches available to designers to assess the reliability of motor drives are detailed in this paper. The first approach is a failure mode and effect analysis (FMEA). This approach is used to identify and list those component failures and combinations of component failures that result in an interruption of operation. The second approach is a so-called calculation of reliability indices which is performed to quantify the reliability of the system and verify that the design requirements are met. A case study of a redundant multilevel motor drive for multi-mega watt gas compression systems is given to illustrate both approaches