A parameter estimation algorithm for induction machines using Artificial Bee Colony (ABC) optimization

Conventionally, parameters of the Induction Motor (IM) are determined using the standard noload and locked rotor test. Performing the no-load test is simple and involved running the machine uncoupled to a load, while measuring the power, voltage, current and shaft speed at different voltage test points. On the other hand, the locked rotor test requires full control of the rotor mechanically in the locked condition before measurements are taken. This paper presents a method for estimating the parameters of IMs without the need for the no-load and locked rotortests. The method is based on optimization approach using a relatively new swarm based algorithm called the Artificial Bee Colony (ABC) optimization. Two different equivalent circuits are implemented for the parameter estimation scheme; one with parallel and the other with series magnetization circuit. Parameters of a standard 7.5kW IM are estimated using the measured and estimated stator current, input and output power and the power factor. Based on the experimental results obtained, the optimization method using the ABC algorithm gave accurate estimates of the IM parameters when compared to the reference parameters determined using the IEEE standard 112-2004. The maximum errors of -13.730% and 2.249% are obtained for the parallel and series equivalent circuits respectively.Keywords: Inductions Machines, Parameter Estimation, Artificial Bee Colony, Magnetization Circuit, Optimization Algorith

Design and Development of Autotransformer Motor Starter for Induced Draft Fan (IDF) of Batangas Sugar Central Inc.

Induction motors as a rotating machine draw a higher current during starting operation than under full load running conditions. With the use of reduced voltage, it limits the adverse effect of the starting current and torque that develops during across the line starting. This is in the case of Batangas Sugar Central Inc. (BSCI) where a wye – delta reduced voltage starting method was utilized in the induced draft fan (IDF) motor. Investigation of the present wye – delta starting method was done to identify the behavior of the voltage, current and torque at different stages of the operation to determine the causes of the operational problem. Performance and characteristics of the current in the present method during the switching transition were found to be defective (5 times the rated value) hence, the reason for analysis. In this study, the characteristics of the various starting method for three phases of induction motors were closely observed and comparison of the stated parameters were made in order to develop a proposed autotransformer motor starter prototype to serve as a basis of starting the IDF motor for the BSCI. Different design requirement based on National Electrical Manufacturers Association (NEMA), Philippine Electrical Code (PEC) and National Electrical Code (NEC) were considered. The voltage, current and torque based on the motor used in the study were computed and the values obtained were compared to the measured value of the parameters using the proposed starting method   in order to ensure reliability, accuracy and applicability. The specification of the autotransformer was computed also based on the actual motor of BSCI and the corresponding values for the input parameters such as voltage, current and torque were then computed and analyzed. The results served as the basis for the BSCI in the implementation of the proposed autotransformer starting method. The computed value of the different input parameters was supported with the measured values using the autotransformer motor starter since the values obtained were almost equal. It showed that the computed value for the starting voltage was almost the same as the actual value. The same thing was true with the computed values of current at different stages in the operation of the motor where it was concluded to be almost equivalent to the measured value using the prototype

Comparison Performance Of Indirect Field Oriented Control For Three-Phase Induction Motor Drive

This paper presents the comparative performances of Indirect Field Oriented Control (IFOC) for the three-phase induction motor. Recently, the interest of widely used the induction motor at industries because of reliability, ruggedness and almost free in maintenance. Thus, the IFOC scheme is employed to control the speed of induction motor. Therefore, P and PI controllers based on IFOC approach are analyzed at differences speed commands with no load condition. On the other hand, the PI controller is tuned based on Ziegler-Nichols method by using PSIM software which is user-friendly for simulations, design and analysis of motor drive, control loop and the power converter in power electronics studies. Subsequently, the simulated of P controller results are compared with the simulated of PI controller results at difference speed commands with no load condition. Finally, the simulated results of speed controllers are compared with the experimental results in order to explore the performances of speed responses by using IFOC scheme for three-phase induction motor drives

Онлайн-идентификация электромагнитных параметров асинхронного двигателя

Incompliance of the settings of the system to control actual values of the parameters of a variable frequency induction electric drive may sometimes result in complete non-operability of a variable frequency electric drive as well as in the considerable reduction of the dynamic quality parameters. Such parameters as active rotor resistance, rotor inductance, and inductance of the magnetization circuit are available for the immediate measuring. They are not identified in terms of the acceptance tests, and the values presented in catalogues and reference books are calculated ones that may differ considerably from the real values of a certain machine. Despite constant studies by the researchers, a task to identify electromagnetic parameters of the equivalent circuit of an induction motor is still important and topical. The objective of the paper is to develop a method of online-identification of the electromagnetic parameters of an induction motor making it possible to implement accurate regulator adjustment of the frequency control system in terms of operational changes in the driving motor parameters. For the first time, the paper analyzes a steady mode of induction motor operation which does not apply T-network of the equivalent circuit of an induction motor. An approach has been proposed relying on the equation of an induction motor in three-phase fixed coordinate system obtained on the basis of the theory of generalized electromechanical converter. Несоответствие настроек системы  управления  фактическим  значениям  параметров частотно-регулируемого  асинхронного  электропривода  может  иногда  приводить  к  полной неработоспособности частотного электропривода, к существенному снижению динамических показателей качества. Такие параметры, как активное сопротивление и индуктивность ротора, индуктивность цепи намагничивания, недоступны для непосредственного измерения. При приемо-сдаточных испытаниях они не определяются, а величины, приводимые в каталогах и справочниках, являются расчетными и могут существенно отличаться от реальных значений конкретной машины. Несмотря на постоянные усилия исследователей, задача идентификации электромагнитных параметров схемы замещения асинхронного двигателя остается важной и актуальной. Авторы статьи разработали метод онлайн-идентификации электромагнитных параметров асинхронного двигателя, что позволит реализовать точную настройку регуляторов системы частотного управления при эксплуатационных изменениях характеристик приводного двигателя. Выполнен анализ установившегося режима работы асинхронного двигателя без использования Т-образной схемы его замещения. Предложен подход, опирающийся на уравнения асинхронного двигателя в трехфазной неподвижной системе координат, полученные на основе теории обобщенного электромеханического преобразователя. С учетом аналитических преобразований этих формул получена система нелинейных алгебраических уравнений четвертого порядка, решение которой позволяет определить активное сопротивление ротора, сопротивление рассеивания и главную взаимную индуктивность асинхронного двигателя в предположении, что активное сопротивление статора известно. Произведена верификация предлагаемого метода. На основании данных установившегося режима работы асинхронного двигателя типа 4А250М2УЗ выполнена идентификация его электромагнитных параметров, исследовано влияние начального приближения на точность полученных результатов, которые подтверждают работоспособность рассматриваемого метода идентификации

Using the instantaneous power of a free acceleration test for squirrel-cage motor parameters estimation

A new parameters determination method for squirrel-cage induction motors is presented. As a main contribution, the method uses the instantaneous electrical power and the mechanical speed measured in a free acceleration test to estimate the double-cage model parameters. The parameters are estimated from the machine impedance calculated at several points. At speed points where the double-cage effect is significant, i.e., between the zero speed point and the maximum torque point, the machine impedance is evaluated by the instantaneous power method, and at speed points where the double-cage effect is not significant, i.e., between the maximum torque point and synchronism, the machine impedance is evaluated by a dynamic-model-based linear least-square method. The proposed method has been applied to obtain the parameters of three motors tested in the laboratory. To check the method accuracy, the steady-state torque and current-slip curves predicted by the estimated parameters are successfully compared with those measured in the laboratory.Postprint (author's final draft

Parameter identification of induction motor

Numerous recent techniques of induction motor parameters calculating are hard to be done and expensive. Accurate calculations of the parameters of these motors would allow savings in different prospective like energy and cost. The major problem in calculating induction motor parameters is that it\u27s hard to measure output power precisely and without harm during the operation of the machines. It will be better to find other way to find out the output power with certain amount of inputs like input voltage and current.;Particle swarm optimization (PSO) and genetic algorithms (GAs) are often used to estimate quantities from limited information. They belong to a class of weak search procedures, that is, they do not provide the best solution, but one close to it. It is a randomized process in which follows the principles of evolution.;In this thesis genetic algorithm and partial swarm optimization are used to identify induction motor parameters. The inputs used to estimate electrical and mechanical parameters are measured stator voltages and currents. The estimated parameters compare well with the actual parameters. Data Acquisition (DAQ) is used to obtain these variable with the help of LABVIEW software. The induction motor used is a 7.5-hp with a constant frequency and in free acceleration. IEEE standard test of 7.5-hp induction motor is used to compare with performance of the simulated and measured data obtained. According to the output results, method of optimizing induction machine can be used in different models of induction motor

Онлайн-идентификация электромагнитных параметров асинхронного двигателя

Incompliance of the settings of the system to control actual values of the parameters of a variable frequency induction electric drive may sometimes result in complete non-operability of a variable frequency electric drive as well as in the considerable reduction of the dynamic quality parameters. Such parameters as active rotor resistance, rotor inductance, and inductance of the magnetization circuit are available for the immediate measuring. They are not identified in terms of the acceptance tests, and the values presented in catalogues and reference books are calculated ones that may differ considerably from the real values of a certain machine. Despite constant studies by the researchers, a task to identify electromagnetic parameters of the equivalent circuit of an induction motor is still important and topical. The objective of the paper is to develop a method of online-identification of the electromagnetic parameters of an induction motor making it possible to implement accurate regulator adjustment of the frequency control system in terms of operational changes in the driving motor parameters. For the first time, the paper analyzes a steady mode of induction motor operation which does not apply T-network of the equivalent circuit of an induction motor. An approach has been proposed relying on the equation of an induction motor in three-phase fixed coordinate system obtained on the basis of the theory of generalized electromechanical converter

Mathematical Modelling of Grid Connected Fixed- Pitch Variable-Speed Permanent Magnet Synchronous Generators for Wind Turbines

This project develops the mathematical model of a 10kW permanent magnet synchronous generator (PMSG), which is designed for a fixed-pitch variable-speed wind turbine, and its corresponding simulation model for the control of the PMSG for grid connection using MATLAB/Simulink. The model includes sub-modules, such as a model of the wind speed, a model of the PMSG, a model of the rectifier circuit, a model of the boost chopper circuit, a model of the space vector pulse width modulation (SVPWM) inverter, and a model of the power grid voltage sag detection for low voltage ride through (LVRT). The rectifier is a 3-phase uncontrolled diode full-bridge circuit. The boost chopper circuit offers a direct current (DC) power supply with constant voltage for the inverter. Sampled signals of instantaneous 3-phase voltage (from the power grid) to obtain the phase angle, frequency and amplitude, are used to generate SVPWM signals to control the inverter’s output. In the model of the power grid voltage sag detection, a novel direct-quadrature (DQ) transformation is introduced to detect the voltage sag of the power grid. This thesis systematically analyses the mathematical model along with its sub-modules, and creates simulation models using MATLAB/Simulink. The simulation results demonstrate that both the mathematical model and simulation model are correct, and the parameters of the generator output are synchronised with the main grid

Determination of the induction machine parameters from starting transient measurements

This Thesis study the parameters estimation of the induction machine with the single-cage and doublecage models, using the stator currents, voltages and mechanical speed from a starting transient. The dynamic equations of the induction machine are expressed in the synchronous reference frame because in this reference the values of the direct and quadrature currents have a slower variation than those in the other reference frames. This reference frame is important to facilitate the data filtering. The proposed method for the single-cage parameters estimation introduces an approximation of the rotor flux using the stator currents and voltages. It has been demonstrated in the thesis that this approximation improves the accuracy of the calculated parameters significantly. Two different methods to calculate the parameters have been developed. The first is based on the linear least-square method and the second on the resolving of a nonlinear system of equations. A detailed error study of the parameters and predicted behavior have been made in the thesis. An interesting result of the error study is that it is very important that the speed of the points be used in the calculations. It is very important to use the points with the maximum torque speed and points near the synchronous speed. The thesis presents the two first methods developed for parameters estimation of the induction machine with double-cage model using data from a starting transient. The other methods known in the literature use steady state data. Both methods use data from the point of maximum torque to the synchronous speed to calculate the parameters of a single-cage model, because the torque- and current-speed curves of this single-cage fit very well with the torque- and current-speed curves of the double-cage. Later, the first method uses a point with a speed near to zero speed and a point in the synchronous speed and other single-cage is calculated. With these two singlecages the impedances of three points are calculated and they are used to estimate the six parameters of the double-cage model solving a nonlinear system of equations. The second method, called instantaneous power method, uses the fact that the averaged transient torque has similar values to the steady-state torque in the mechanical transient region. Then, several impedance values are calculated for points with different speeds in this region, where the effects of the double-cage are more important. Finally, with impedance values in the synchronous speed and the maximum torque speed obtained with the regression method and impedance values obtained with the instantaneous power method, a set of non linear equations are defined. Their solution is the estimated parameters of the induction machine double-cage model

Electrical instrumentation of a contra-rotating propeller drive system

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, February 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 11).A prototype ship propulsion device based on an electric motor that spins propellers in opposite directions was constructed and tested. The device uses a single motor to spin both propellers without a gearbox. The rotor is attached to one propeller and the stator to the other. It relies on the propellers to balance rotational speeds of the two shafts. Non-intrusive Load Monitoring (NILM) techniques were used to diagnose performance of the machine. This analysis confirmed a sensor failure in testing.by Matthew G. Angle.M.Eng