DC-Link Sensor Fault Detection and Isolation for Railway Traction Electric Drives

This article presents the design and the implementation of a fault detection and isolation strategy for sensors in variable speed drives. Electric drives use several current and voltage sensors for control and protection. The principal objective of the strategy is to detect faults in DC-Link sensors, since the conclusion of a preliminary study showed that in some applications many functionalities in the control strategy depend on it. Although it was mainly designed for DC-Link sensors, thanks to the FDI structure presented here, the algorithm is able to detect faults in other sensors. The strategy is based on state observers and has been validated through real time simulations in a Hardware-in-the-Loop platform. The principal components of the platform are an OPAL-RT real time simulator and a commercial traction control unit.