https://users.encs.concordia.ca/~ymzhang/publications/ARC32-2-98Zhang_pp.229-252.pdf

Bibliographical review on reconfigurable fault-tolerant control systems

Inverters play key roles in motor drives, flexible power transmissions, and recently grid-tied renewable energy generation units. Therefore, availability and reliability of inverters have become increasingly important. Following early stage fault detections in inverters, remedial actions can extend normal operation of inverters and, in some cases, derate the system to prevent unexpected shutdowns. A remedial action typically contains a combination of hardware and software reconfigurations. The main purpose of this paper is to provide an instructive survey of existing fault-tolerance (remedial) techniques for three-phase, two-level, and multilevel inverters.

Survey of Fault-Tolerance Techniques for Three-Phase Voltage Source Inverters

A novel fast-diagnostic method for open-switch faults in inverters without sensors is proposed to improve the reliability of power electronic system in this paper. The presented method is achieved by analysis of switching function model of the inverter under both healthy and faulty conditions. Due to the different voltages endured by each power switch under healthy condition from open-switch faults in some cases, open-circuit faults can be detected by sensing the collector-emitter voltages of the lower power switches in each leg. The diagnostic scheme employs the simple hardware circuit to obtain indirectly the voltages of lower power switches and to get rid of high cost and complexity as a result of sensors. Also, this method minimizes the detection time and is available for the inverter faults in the systems with open-loop or closed-loop current control strategies. To ensure the effectiveness and reliability of the proposed diagnostic method, the rising-edge delays for switching signals are used to avoid misdiagnostic results because of the ON-OFF processes of power switches, and the delay durations are determined considering various factors. Simulation and experimental results validate the proposed scheme for detecting switch and leg open-circuit faults.

Switching Function Model-Based Fast-Diagnostic Method of Open-Switch Faults in Inverters Without Sensors

This paper proposes control algorithms for a fault-tolerant permanent-magnet synchronous motor (PMSM) drive. In order to improve the reliability of the drive, an algorithm for achieving a sensorless control that operates properly also in fault mode is proposed. Furthermore, it is shown how a closed-loop field-weakening controller needs to be modified in order to operate properly in fault mode. Automotive applications are in mind and the algorithms presented are verified with experimental results using an in-wheel PMSM. With the proposed modifications, the reliability of the drive can be improved.

Control Algorithms for a Fault-Tolerant PMSM Drive

In this paper, a generalized optimal fault-tolerant control (FTC) technique is proposed for open-circuit faults in five-phase permanent-magnet (PM) machine drives. The proposed FTC technique considers pentagon and pentacle connections of stator windings in addition to conventional star connection. Open-circuit faults in stator windings of the machine as well as switches of the inverter are analyzed. The optimization objective is to produce ripple-free electromagnetic torque with minimum ohmic losses under open-circuit fault conditions. This is achieved by a simple closed-form equation to calculate reference optimal currents in all cases where a lookup table is utilized to represent the effect of fault type. The proposed FTC technique is easily extended to PM machines with higher number of phases. Experimental results for a five-phase PM machine drive are provided to demonstrate the proposed FTC strategy. In addition to single and double faults, which are analyzed for five-phase machine with star connection, triple-phase faults are also considered in pentagon and pentacle connections.

A Generalized Fault-Tolerant Control Strategy for Five-Phase PM Motor Drives Considering Star, Pentagon, and Pentacle Connections of Stator Windings

Interior permanent magnet (IPM) synchronous motors are used extensively in many industrial drives, and the development of fault-tolerant control techniques may extend their use to applications where high reliability, also in the flux-weakening region, is a key-feature. This paper proposes some innovative fault-remedial control strategies for failures occurring in the drive voltage inverter.

Zordan

Papers

Innovative Remedial Strategies for Inverter Faults in IPM Synchronous Motor Drives