MRAS-Type Speed and Flux Estimator with Additional Adaptation Mechanism for the Induction Motor Drive

This paper deals with a novel Model ReferenceAdaptive System (MRAS) estimator of the rotor flux andspeed reconstruction for induction motor drive. Theproposed estimator is based directly on the mathematicalmodel of the induction motor. In comparison with existingmethods the additional variable is introduced, which has toreduce partly the estimator sensitivity to the rotor timeconstant changes. Chosen simulation tests of the proposedsolution are presented

Primjena dijagnostičke metode za IGBT grešku otvorenog kruga u asinkronom motornom pogonu s vektorskom modulacijom i izravnim upravljanjem momentom

In this paper a simple diagnostic method of a single IGBT open-circuit fault is presented, it is dedicated for three-phase two-level voltage-inverter-fed vector controlled induction motor drive systems. A failure diagnosis is based on a transient analysis of a reference voltage space vector in stationary coordinates, without additional sensors. The diagnostic algorithm ensures detection and localization of single IGBT failures in time shorter than one period of a stator current fundamental harmonic, without regard to a drive operation point. The presented scheme of the diagnostic system can be easily applicable in the electric drives that use voltage space vector modulation algorithms. The main achievement of the research, whose results have been presented in this paper, is an experimental validation of the analyzed IGBT faults diagnosis technique in the drive with the Direct Torque Control algorithm.U ovom radu prikazana je jednostavna dijagnostička metoda jedne IGBT pogreške otvorenog kruga, namijenjena je za sustave asinkronog motornog pogona s trofaznim dvorazinskim pretvaračem s vektorskim upravljanjem. Dijagnoza pogreške zasnovana je na analizi tranzijenta referentnog vektora napona u stacionarnim koordinatama bez dodatnih senzora. Dijagnostički algoritam osigurava detekciju i lokalizaciju jedne IGBT greške u vremenu kraćem od jedne periode fundamentalnog harmonika struje statora neovisno o trenutnom operacijskom stanju pogona. Prezentirana shema dijagnostičkog sustava može se jednostavno primijeniti u električnim pogonima koji koriste algoritme vektorske modulacije naponskih vektora. Glavno postignuće istraživanja, čiji su rezultati prikazani u ovom radu, je eksperimentalna validacija analiziranih dijagnostički tehnika za IGBT greške u pogonu s algoritmom za izravno upravljanje momentom

Analiza kvarnih stanja rotora vektorski upravljanog asinkronog stroja bez mehaničkog senzora brzine vrtnje

In the paper an analysis of the Direct Field Control of induction motor drive with broken rotor bars is presented. A drive system with and without a mechanical speed sensor is analyzed. In the sensorless induction motor (IM) drive the rotor flux and speed is reconstructed with the use of a MRASCC estimator, where the induction motor is used as a reference model. The stator current estimator and current model of the rotor flux are used as adapted models. Most of the speed estimators used in sensorless drives are sensitive to motor parameter changes, especially to the rotor resistance changes. The proposed MRASCC estimator is very robust to all motor parameter changes, hence it should work properly in a faulty rotor. In the paper simulation and experimental results of the sensorless IM drive with broken rotor bars are presented. Characteristic frequency harmonics of the IM state variables connected with the broken rotor bars are introduced. The low speed region and the dynamic properties of the IM drive with rotor faults are tested. The range of stable work of the control system is shown.U radu je prikazano izravno upravljanje poljem asinkronog motora s prekinutim rotorskim štapovima. Analiziran je elektromotorni pogon s mehaničkim senzorom brzine i bez njega. Pri upravljanju bez mehaničkog senzora brzine rotorski tok i brzina rekonstruirani su korištenjem MRASCC estimatora, pri čemu je asinkroni stroj korišten kao referentni model. Estimator statorske struje i strujni model rotorskog toka korišteni su za adaptaciju modela. Većina estimatora brzine vrtnje koji se koriste u pogonu bez mehaničkog senzora brzine osjetljivi su na promjenu parametara stroja, posebno na promjenu rotorskog otpora. Predloženi je MRASCC estimator robustan na promjene parametara motora pa je moguć rad i u kvarnom stanju rotora. U radu su prikazani simulacijski i eksperimentalni rezultati pogona bez mehaničkog senzora brzine pri prekinutim rotorskim štapovima. Uvedene su frekvencije karakterističnih harmonika varijabli stanja asinkronog motora povezane s prekinutim rotorskim štapovima. Analizirano je područje malih brzina vrtnje te dinamičke značajke pogona s asinkronim motorom s rotorom u kvarnom stanju. Prikazano je područje stabilnog rada sustava upravljanja

Industrial applications of the Kalman filter:a review

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Influence of the stator current reconstruction method on direct torque control of induction motor drive in current sensor postfault operation

Modern induction motor (IM) drives with a higher degree of safety should be equipped with fault-tolerant control (FTC) solutions. Current sensor (CS) failures constitute a serious problem in systems using vector control strategies for IMs because these methods require state variable reconstruction, which is usually based on the IM mathematical model and stator current measurement. This article presents an analysis of the operation of the direct torque control (DTC) for IM drive with stator current reconstruction after CSs damage. These reconstructed currents are used for the stator flux and electromagnetic torque estimation in the DTC with space-vector-modulation (SVM) drive. In this research complete damage to both stator CSs is assumed, and the stator current vector components in the postfault mode are reconstructed based on the DC link voltage of the voltage source inverter (VSI) and angular rotor speed measurements using the so-called virtual current sensor (VCS), based on the IM mathematical model. Numerous simulation and experimental tests results illustrate the behavior of the drive system in different operating conditions. The correctness of the stator current reconstruction is also analyzed taking into account motor parameter uncertainties, especially stator and rotor resistances, which usually are the main parameters that determine the proper operation of the stator flux and torque estimation in the DTC control structure

Self-Correcting Virtual Current Sensor Based on the Modified Luenberger Observer for Fault-Tolerant Induction Motor Drive

Fault-tolerant control (FTC) solutions are increasingly being used in modern drive systems with AC motors. Such systems provide a higher degree of security and solutions that allow the on-line detection and localization of failures, as well as the switching of the control mode to a mode that allows us to continue the operation or safely stop the drive system. As the current sensors (CSs) are necessary to ensure precise control of the AC motors, in the event of their failure, one of two strategies can be used—hardware or software redundancy. The first strategy requires the use of additional measuring sensors. For this reason, the algorithmic solution, based on the Luenberger Observer (LO), has been proposed in this article as one of the software redundancy methods. In contrast to methods presented in the literature, the proposed solution allows one not only to compensate the stator current in a phase with a faulty CS, but also to adjust the correction of current estimation based on a measured signal in the other phase with a healthy CS. Extensive simulation studies in the direct rotor flux-oriented control (DRFOC) structure with the induction motor (IM) confirm the effectiveness of the proposed method. In addition, the proposed solution allows the drive system to be controlled even if all CSs are damaged