Coupled Fault-Tolerant Control of Primary Permanent-Magnet Linear Motor Traction Systems for Subway Applications

In this article, a coupled fault-tolerant control (C-FTC) is proposed for primary permanent-magnet linear motor traction system in subway applications. By coupling the faulty mover with a healthy mover, the proposed C-FTC can achieve continuous operation of the faulty mover, in which one or more current sensors fail. A healthy mover is determined as the reference mover. The switch-states of the reference mover are also applied to its mathematical model. As a result, synchronous currents of the reference mover are also estimated from its mathematical model, and they are treated as the reference currents of the mathematical model of the faulty mover. Hence, the switch-states of the faulty mover can be determined. Therefore, the faulty mover can be controlled without any current sensors. The key of C-FTC is to compensate the parameter variations and the nonlinear effects of the faulty mover drive system with those of a healthy mover drive system, which is the main contribution of this article. Comparing with the conventional current-sensorless control, C-FTC has stronger robustness to the parameter variations and the nonlinear effects. The effectiveness and robustness of the proposed C-FTC are verified by simulation and experimental results.