Current sensor fault tolerant control of permanent magnet syschronous machine

Abstract

To ensure the safety operation and service continuity of control systems, a control technique appeared called Fault-Tolerant Control (FTC). It enables the detection and isolation of faults, as well as the reconfiguration of the control system, to ensure continuity of service and to protect the healthy components from the effects of failing elements. Certainly, several works have been carried out on this subject in different fields of application, among them: the current sensors faults presented in the AC electric drives based on motors like Permanent Magnet Synchronous Motors (PMSMs). These kind of motors are widely used in the industry for variable speed applications due to their high performance reliability and power density. However, in order to achieve fault-tolerant control of current sensors faults , it is necessary to ensure the correct compromise between the detection of faulty sensors and the reconstruction of the currents. In this context, many methods have been proposed for the detection or estimation of three-phase stator currents. Apart from fault detection, current estimation is frequently based either on several cascaded observers, a current sensor and a voltage sensor in the converter DC bus, or an observer and a healthy line current sensor. In this work, the estimation of three-phase stator currents is approached by proposing a method based only on a single current observer, which ensures the estimation and correction of the three stator currents even in case of failure of all current sensors (Current sensorless). This method was then combined with a conventional fault detection and isolation circuit (FDI) and field oriented control (FOC), where the assembly is an active fault-tolerant control for current sensors. Another fault tolerant control method against current sensor faults based on a speed robust controller is named passive fault tolerant control (PFTC). Both methods proposed in this work were applied on an SPMSM. Promising results were obtained in simulation on Matlab/Simulink.