Piotr Sobanski

Simple sensorless diagnosis method for open-switch faults in SVM-VSI-fed induction motor drive

In this paper a new simple diagnostic technique of single IGBT open-circuit faults for a two level voltage inverter-fed field oriented controlled induction motor drive is presented. A failure diagnosis is carried out utilizing a reference voltage vector analysis in stationary coordinates, without additional sensors. An extraction of fault information is based on monitoring the voltage vector time presence in specific sectors of the complex stationary plane. Thanks to diagnostic signal normalization, high robustness to false alarms is guaranteed. To validate the proposed method, simulation tests under a wide range of working conditions of the induction motor are presented for the direct field-oriented controlled drive system.

Faults diagnosis and control in a low-cost fault-tolerant induction motor drive system

The paper deals with faults diagnosis and control methods for a fault-tolerant direct field-oriented controlled by Space Vector Modulation (SVM) two-level voltage-inverter-fed induction motor drive. In order to maintain an uninterrupted motor drive operation even under its faulty condition, two diagnostic algorithms as well as post-fault control techniques are developed. According to the first diagnostic system, that is related to single open-circuit faults in two-level voltage inverter, a failure diagnosis is performed by monitoring a time presence of a reference inverter voltage vector in particular sectors of the α - β coordinate system. After the fault detection, to maintain a high-quality drive performance, a switch-redundant inverter scheme is utilized. In case of the second diagnostic system, for the speed sensor failure detection, a motor speed estimator, that is based on a model reference adaptive system, is utilized. This algorithm is used for the post-fault motor drive operation as well. Both fault monitoring methods are based on a software solution, therefore they do not generate additional implementation costs.To validate the described fault-tolerant control scheme, chosen simulation tests, which were carried out in MATLAB/Simulink, are presented. Additionally, in case of the transistor failure diagnosis, experimental tests were carried out. The analysis of the inverter voltages under the drive faulty mode was carried out.The open-switch fault diagnostic technique was experimentally proved.The speed sensor fault diagnosis was achieved by model reference adaptive system.The post-fault drive operation was provided under the unbalanced DC-link voltages.Both diagnostic techniques were based on a software solution.

Analysis of space vector modulation technique in inverter-fed fault-tolerant induction motor drive

This paper presents a designing and an analysis of a space vector modulation (SVM) algorithm in a fault-tolerant induction motor drive system based on a redundant voltage inverter topology. First, an influence of open-switch failures on inverter voltages modulation is considered. Furthermore, limitations of the post-fault SVM method are specified. To validate the analyzed algorithm, a simulation model of the drive was designed in the Matlab/Simulink.

Predictive flux and torque control of induction motor drive under post-fault operation of three-phase voltage inverter

In this paper a direct finite-state predictive flux and torque control of an induction motor drive system fed by four-switch three-phase voltage inverter was discussed. This specific inverter topology can be used after faulty inverter leg isolation from an electric motor under single IGBTs open-circuit faults. To overcome a significant problem related to the four-switch inverter topology, namely capacitor voltage unbalance in DC-link, a solution based on the voltages measurement was developed. In the proposed approach, depending on a motor drive operation point, in order to achieve a high drive performance a weighting factor of a cost function term related to capacitor voltages balance is adapted. To confirm the proposed method, simulation results were presented under a wide range working conditions of an induction motor drive system.

Electrical faults diagnosis in the induction motor drive under the direct field oriented control

This paper deals with the diagnosis of the electrical faults of induction motor operating under the direct field-oriented control. Two different faults are taken into account: stator winding inter-turn short circuit and voltage source inverter transistor damage. The fault diagnostic algorithms are described. Performance of both algorithms is validated in presence of the different kind of damages. The presented methods are examined using the experimental setup with specially prepared induction motor and voltage source inverter.

Open switch fault diagnosis methods for an AC/DC line-side converter

This paper provides an open switch fault diagnosis method for a voltage oriented controlled AC/DC line side converter. The technique is based on rectifier phase voltage errors calculations. For the faulted transistors localization, the average voltage errors of the rectifier are computed and their values and signs are analyzed. The proposed method is valid under the rectifier as well as the regenerative mode of the converter. Additionally, the algorithm does not generate false alarms during a healthy operation of the rectifier. Further, an assumed fault threshold, which is required for the transistor failure detection, is constant and does not depend on a grid choke inductance. The proposed method is characterized by a short diagnosis time and full effectiveness. To validate the proposed diagnostic algorithm Matlab/Simulink has been used.

Rotor-Flux-Based diagnosis method for igbt open-circuits faults in a field-oriented-control induction motor drive

The paper deals with a single-switch IGBT open-circuit faults diagnosis of a two-level voltage inverter supplying an induction motor controlled in a direct rotor field oriented system. The proposed transistor failures diagnostic algorithm is based on an analysis of an estimated rotor flux as well as a measured stator current space vector in a stationary reference frame. The analyzed solution ensures a fast fault detection time, which is shorter than one period of a stator current fundamental harmonic, without regard to a motor drive operation point. In order to prove a full robustness against false alarms and high effectiveness of the proposed fault diagnostic method, experimental tests have been carried out, whose chosen results are presented in this paper.

A stator-flux-based diagnostic method for IGBT open-circuit faults in an induction motor drive

this paper addresses a single-switch IGBT open-circuit faults diagnosis of a two-level voltage source inverter in an induction motor drive system with the direct torque control (DTC) strategy. The proposed diagnostic algorithm consists in the analysis of a stator flux vector amplitude and its position in a stationary reference frame. In accordance with this method the inverter fault is detected when an abnormal local minimum of the stator flux amplitude is observed. Furthermore, for the fault localization the information about a stator currents polarity is processed. Full robustness against false alarms and high effectiveness of the proposed fault diagnostic method has been proved by experimental tests, whose selected results are presented in this paper.

Multiple transistor open-circuit faults diagnosis in a vector-controlled induction motor drive

The paper deals with a transistor open-circuit faults diagnosis in a rotor field oriented controlled induction motor drive fed by a two-level voltage inverter. The diagnostic procedure ensures to detect and localize single power switch failures as well as single-phase transistor faults in a time shorter than one period of a stator current fundamental harmonic, without regard to a drive operation point. In accordance with this paper, a new simplified scheme of the diagnostic system is proposed. The presented solution requires a low-computational effort and it is easy applicable in modern electrical drives. In order to validate the proposed faults diagnostic method, detailed experimental tests were carried out and some of them are shown in this paper.

Experimental validation of the simple voltage-vector-location-based method of open-circuit IGBTs faults in DTC-SVM induction motor drive

This paper deals with an open-circuit IGBTs faults diagnostic method that is dedicated for three-phase two-level voltage inverter fed vector controlled induction motor drive systems. The presented technique is based on a transient analysis of a reference voltage space vector in a stationary reference frame and it does not require an extra sensors application. The diagnostic algorithm ensures to detect and localize single power switch failures in a time shorter than one period of a stator current fundamental harmonic, without regard to a drive operation point. The presented sheme of the diagnostic system can be easy applicable in the electric drives that used voltage space vector modulation (SVM) algorithms. The main achievement of the research, whose results have been presented in this paper, is experimental validation of the IGBTs faults diagnosis technique in the drive with the Direct Torque Control (DTC) algorithm.