Control of Synchronous Motors

Chapter 7

Synchronous Machine and Inverter Fault Tolerant Predictive Controls ¹

7.1. Introduction

Electric drives (machine and converter) are prone to many faults that can lead to an inability to ensure the requested functionality, if nothing has been planned. This situation is undesirable and can become unacceptable for some applications, where service continuity or peoples‘ safety are at stake. We mainly find these applications in aeronautics or in the current (electric power steering) and future (Drive by wire) automobile industry. Fault tolerant functioning must then be planned. Fault tolerance can have several meanings: it can help a drive to survive a temporary fault, such as a short-circuit or to ensure its main function [MEC 96], [BIA 04], even in deteriorated mode if necessary. In this last case we talk about the functioning safety. The functioning safety mainly uses the component redundancy and is often confused with the reliability. Reliable components improve the functioning safety, but the components‘ redundancy reduces the reliability of the set, by increasing the instances of faults, while helping to increase the functioning safety.

Tolerance to machine faults is often associated with the redundancy brought by the increase in the phase number [LOC 07]. However, this chapter is limited to the study of three-phase synchronous machines, multi-phase machines with more than three phases will be presented in the forthcoming book [KES 11]. Some design elements of the machines ...