In the paper, an analysis is made of the stator current sensor fault detector based on artificial neural network for vector controlled induction motor drive system. The systems with different learning algorithms and structures are analyzed and tested in different drive conditions. Simulation results are ob-tained in direct torque control algorithm (DTC-SVM) and performed in MATLAB/SimPowerSystem software.
The article presents an analytical description of the turn-off process of the power MOSFET suitable for use in high-frequency converters. The purpose of this description is to explain the dynamic phenomena occurring inside the transistor and contributing to the switching power losses. The detailed description uses the results of simulation studies carried out using a very precise model of the CoolMOS transistor manufactured by Infineon (IPW60R070C6). The theoretical analysis has been verified in experimental measurements of power dissipated during turn-off transient of MOSFET operating in a full bridge converter with switching frequency of 100 kHz. To estimate these switching losses an original thermovision method based on the measurement of heat dissipated in the power semiconductor switches has been used. The obtained results confirm the correctness of the conclusions drawn from the theoretical analysis presented in this paper.
The paper presents a Direct Field-Oriented Control (DFOC) of six-phase induction motor with Fuzzy-Logic speed controller. Mathematical models of the six-phase squirrel-cage induction motor and the six-phase voltage source inverter have been presented. A method of space vector modulation used to control a six-phase voltage source inverter has been described. Simulation studies of the DFOC with Fuzzy-Logic speed controller have been carried out and the results presented and discussed.
This paper presents predictive speed control of induction motor. The structure with finite control set and long prediction horizon is proposed. In methods with finite set of solutions there is assumed the use of signals that can be obtained in inverter only. Long prediction horizons allow better performance of predictive control structures to be achieved. In this case, long prediction horizon refers to systems with more than one prediction step. The weighting factors determine the properties of control structure via an optimization method using genetic algorithms. The results of simulation studies has been presented.
The article presents the current state and development trends of electrical drives, with particular emphasis on modern control structures and safety systems of various types of electrical machines. Special attention was paid to the needs of industrial drive systems and a possibility of practical implementation of complex control algorithms. Development perspectives of electrical drives are discussed from the perspective of new trends in control, power electronics and electrical machines, with consideration given to systems robust to faults of drive system elements.
The paper presents conclusions which are results of research on the use of high-speed drives operating in household appliances. The solutions that use three-phase or two-phase induction motors were taken into consideration. The assumed power of motors was up to 1 kW. The article describes the control process of power converters that is characterized by unity power factor and output voltages with the fundamental frequency up to 667 Hz. The requirements for control process were characterized and intelligent solutions were analysed, taking into account power outages, fluctuations, or accidental failures of supply voltage. The control functions of the controller elaborated, such as current and speed control, drive start-up and control circuit supply were described.
The article presents control strategy for the operation of a variable-speed wind energy conversion system with permanent magnet synchronous generator (PMSG). The electrical system of wind turbine consists of PMSG, Switch Mode Rectifier (SMR) and Grid Side Converter (GSC). The SMR converter is composed of an uncontrolled diode bridge and a DC/DC boost converter. In the control of the DC/DC boost converter the algorithm of Maximum Power Point Tracking (MPPT) has been applied. The MPPT algorithm allows the wind turbine to operate at maximum value of power coefficient in a wide range of wind speed. In the control of Grid Side Converter a method of Voltage Oriented Control (VOC) has been applied. High efficiency and accuracy of this control system were confirmed by simulation studies.
Adam Gozdowiak, Piotr Kisielewski and Ludwik Antal
The present paper shows the simulation results of turbogenerator faulty synchronization with inverse phase sequence. Great emphasis is placed on the physical phenomena existing in the rotor because the measurement of rotor damper bar currents is difficult in practice. There are presented the comparisons of maximum magnitudes of stator current and electromagnetic torque determined during faulty synchronization with maximum magnitudes designated during sudden short circuit after both no-load and rated operation condition. In addition, the effect of synchronizing limits on faulty synchronization is presented.
The paper presents a high-speed induction motor drive as an alternative for household appliances. A short comparison was made between standard and high-speed motors. The solutions that use three-phase induction motors were taken into consideration with different types of rotors: solid or squirrel-cage. The assumed power of drive was up to 1 kW. As the power source, a single-phase voltage source has been adopted, which was indirectly converted to a three-phase output voltages with the fundamental frequency up to 667 Hz.
A mathematical model of a squirrel-cage induction motor with inter-turn short-circuits in stator phases is presented in this paper. In the proposed mathematical model an extent and angular localization of short-circuit faults are determined using a simple form of short-circuit coefficient matrices. The model does not require any additional motor parameters than those that are required for conventional model of healthy induction motor. Comparative results obtained through computer simulations and from a laboratory test-stand with 2.2 kW induction motor are contained in the article. The results obtained validate the proposed extended mathematical model of a squirrel-cage induction motor with inter-turn short-circuit of stator windings.