Published Paper Details:

Fault-tolerant control systems are attracting more interests due to its ability of increasing the reliability of voltage source inverts (VSI). Fault identification, localization and fault tolerant control schemes of current sensor are presented here for high fault tolerance induction motor drives. Practically three phase current sensors are used in high power inverters to read the stator currents and allow the drives to work accordingly. But on failure of current sensors it degrades the performance and reliability of drives, even it leads to the breakdown of the vector control system due to the fact that flux angle cannot be estimated correctly. The proposed scheme consists three separate observers, taking a-phase current, b-phase current and c-phase current as inputs, respectively. The observers are having ability to monitor the state of current sensors under normal operation online. Further, after one or even two current sensors getting faulty, the observers can detect and localize the faults and switch the system to tolerant vector control mode even with only one healthy phase current sensor available. Hence, it is very attractive in some safety crucial applications. Stability and convergence of the observer are mathematically derived and verified. A Matlab/Simulink based 1.1kW induction motor variable speed system is setup for the verification of the proposed algorithm