Permanent magnet synchronous motors (PMSMs) drives using three-phase voltage-source inverters (VSIs) are currently used in many industrial applications. The reliability of VSIs is one of the most important factors to improve the reliability and availability levels of the drive. Accordingly, this paper presents a robust fault diagnostic method for multiple insulated gate bipolar transistors (IGBTs) open-circuit faults and current sensor faults in three-phase PMSM drives. The proposed observer-based algorithm relies on an adaptive threshold for fault diagnosis. Current sensor and open-circuit faults can be distinguished and the faulty sensors and/or power semiconductors are effectively isolated. The proposed technique is robust to machine parameters and load variations. Several simulation and experimental results using a vector-controlled PMSM drive are presented, showing the diagnostic algorithm robustness against false alarms and its effectiveness in both IGBTs and current sensors fault diagnosis.

In order to increase the reliability and availability of wind turbines, condition monitoring and fault diagnosis are considered crucial means to achieve these goals. In this context, direct drives wind turbines based on permanent-magnet synchronous generators (PMSGs) with full-scale power converters are an emerging and promising technology. However, several statistical studies point out that power converters are a significant contributor to the overall failure rate of modern wind turbines. Accordingly, this paper presents a new algorithm for multiple open-circuit faults diagnosis in full-scale back-to-back converters, applied in PMSG drives used for wind turbine systems. The proposed method is based on a Luenberger observer and on an adaptive threshold, which can guarantee a reliable diagnosis independently of the drive operating conditions. Several simulation and experimental results using a PMSG drive with a full-scale converter are presented, showing the diagnostic algorithm effectiveness and robustness against false alarms for both generator- and grid-side converters.

Fault detection and fault accommodation as well as fault tolerance are important issues in closed-loop controlled three-phase converters. For such systems, power semiconductors and sensors are the most affected components by the occurrence of failures. Therefore, fault diagnosis and remedial operating strategies involving such components are highly required. In this work we propose a new reliable approach which aims to diagnosis current sensors and power semiconductors open-circuit faults in a permanent magnet synchronous motors (PMSM) drives. The proposed FDI scheme uses only the measured currents, which makes it suitable for real time implementation. The performances of the proposed technique are analyzed through experiments.

Interturn short-circuit faults are one of the most (if not the most) harmful electrical machine failures, that if not detected and mitigated at a very incipient stage of development may involve serious consequences, both in terms of repair costs and safety. This article proposes a novel interturn fault diagnostic technique for synchronous reluctance machines based on the Luenberger state observer and current's second-order harmonic. The superiority of the proposed approach over the conventional model-based techniques is the ability to evaluate the severity of the fault as well as the efficiency in detecting faults in early stages and under various operating conditions. The effectiveness of the proposed method is demonstrated and validated through several experimental tests.

Fault-tolerance in wind turbines is considered crucial to increase their reliability and availability levels. This paper presents a fault-tolerant direct-drive permanent magnet synchronous generator (PMSG) using new direct control techniques, with the ability to handle power semiconductor open-circuit (O-C) faults in the full-scale back-to-back converter. The fault-tolerant topology consists of a five-leg converter, with a shared leg connected to a generator phase and to its corresponding grid phase, through a TRIAC. The main contribution of this paper consists of the development of an alternative direct torque control (DTC) and direct power control (DPC) schemes for both machine-side converter (MSC) and grid-side converter (GSC), respectively. Moreover, a reliable fault diagnostics algorithm without requiring additional sensors is also integrated, providing the information required to instantaneously trigger fault-tolerant remedial strategies. Simulation and experimental results are presented to validate the effectiveness of the proposed fault-tolerant PMSG drive.

This paper proposes a single fault diagnostic method for regenerative permanent magnet synchronous machine drives with the ability to handle multiple IGBT faults, single current sensor fault and rotor-position disconnection. The considered faults are discriminated and the faulty device is correctly identified in each case. The robustness against false alarms is improved by using adaptive thresholds and normalized diagnostic variables. The proposed algorithm requires the information given by current sensors and the rotor position sensor that are already available from the drive system, without requiring a high computational burden. Simulation and experimental results are presented to validate the effectiveness of the considered algorithm for both motoring and regenerative operations.