Fast fault detection, isolation and reconfiguration in fault-tolerant permanent magnet synchronous motor drives

This paper presents a variable speed ac drive based on a permanent magnet synchronous motor, supplied by a three-phase fault-tolerant power converter. With the aim to develop a fully automated fault-tolerant drive, special control routines were incorporated into the drive main controller that allow the control system to accomplish four important tasks, namely inverter fault diagnosis, faulty leg isolation, hardware reconfiguration and post-fault control optimization. The fault-tolerant control system integrates a reliable, fast and simple algorithm for real-time diagnostics of inverter open-circuit faults. This algorithm performs an important role since it is able to detect an inverter malfunction, and simultaneously providing information about its faulty phase. The control system acts in order to isolate the fault, performing then a hardware reconfiguration and a post-fault control optimization. By doing this, an inverter malfunction can be rapidly handled through a fast fault detection and reconfiguration process, minimizing the impact on the drive overall performance. Experimental results are presented showing the effectiveness of the developed fault-tolerant drive system.