Circuit Parameters Of Induction Motor Research Articles

Estimation of the Equivalent Circuit Parameters of Induction Motors by Laboratory Test

The determination of equivalent circuit parameters for AC induction motors represents an important task in an electrical machine laboratory. Frequently used open-circuit and short current tests answer these requirements. However, the results have a low accuracy. This becomes especially obvious when the equivalent circuit is applied for the motor current and power prediction. The main obstacles in this circumstance lie in the difficulty of providing a pristine open-circuit test, the lack of which causes errors in parameter estimation. A much more accurate approach can be carried out with a test including several output points with measurements of the motor torque, velocity, current, and power magnitudes. Nevertheless, a relatively simple and accurate method to ensure determining parameters for such tests does not exist. This article tries to provide such a method by an approach based on Kloss’s simplified equation and the Thevenin theorem. The significant novelty of the method is the specially selected synergetic interaction between the analytical and numerical approaches, which give a relatively simple algorithm with a good accuracy and a convergence of the parameters’ estimation.

Simplified algorithm for assessment equivalent circuit parameters of induction motors

Induction or asynchronous AC motors are widely used in the electromechanical industries. However, the selection of an appropriate motor for specific drive applications represents a non-trivial task. The most effective and universally accepted method is to use equivalent T-circuit for this purpose. Parameter determination of equivalent circuit should be done relatively fast and accurately. This article describes a novel and simplified method for the estimation of equivalent circuit parameters, which is exclusively based on the manufacturer's datasheet. The proposed method is based on the synergetic interaction between the numerical and analytical dimensionless approach using the Thevenin theorem. Initially, rated motor parameters and unknown variables of the equivalent circuit are combined into dimensionless expressions using the Thevenin approach. This method is simple, original, and useful to prevent instability in the numerical solution. Importantly, the high convergence of a solution and relatively fast calculation of parameters reveals the significant novelty of the proposed method. This method provides accurate and sustainable results for a wide range of low voltage asynchronous motors with different rotational velocities, torque, and power range from a few to hundreds of kilowatts. The proposed method is validated by the application of three types of asynchronous AC motors.

A Simple Method to Determine Double-Cage Rotor Equivalent Circuit Parameters of Induction Motors From No-Load and Locked-Rotor Tests

This paper presents a simple method to determine double-cage rotor equivalent circuit parameters of induction motors (IMs). A new formula to calculate the double-cage rotor equivalent circuit parameters is proposed. The formula is sufficiently simple to be calculated by a calculator but can determine the parameters of outer- and inner-cage conductors. The proposed method takes the magnetic saturation effect of a closed-slot rotor into account and applies to not only double-cage but also single-cage IMs. All equivalent circuit parameters can be determined using only classical no-load and locked-rotor tests. Thus, the proposed method is suitable to be used as a standardized testing method for IMs. The validity of the proposed method is demonstrated by experimental results on four 5.5 kW-200 V-4 P-22 A-50 Hz IMs: double- and single-cage IMs with semi-closed- and closed-slot rotors.

FEATURES OF PARAMETER DETERMINATION OF THE INDUCTION MOTOR SUBSTITUTION CIRCUIT FOR SHORT-CIRCUIT MODE

Purpose. Development of a new method for determining the parameters of an induction motor, based on a three-dimensional transient mathematical model of the electrical and magnetic fields, that provides high accuracy and reliability of results and considering the design features of induction motors, nonlinearity of the electrophysical and magnetic properties of active and structural materials. Methods. Numerical simulation of the conjugate spatial transient electrical and magnetic fields of the induction motor in the short-circuit mode, with help methods of the theory of electromagnetic fields, finite element, theory of electrical machines and electrical circuits. Results. Theoretical researches and simulation results, which based on numerical realization of the finite element method of three-dimensional transient mathematical model of the electrical and magnetic fields in induction motor which displayed the features of the processes of AC energy conversion in the experimental short-circuit mode are obtained. The magnetic field energy is localized mainly in the area of the cores and slots of the stator and rotor of the low-power induction motors by researches was determined. In the zone of the frontal parts of the stator windings, up to 15% of the magnetic field energy of the induction motor is evolved. In the central area of the active part of the induction motor, a length up to 60% of the total length of the stator and rotor core, the magnetic field has plane-parallel form, but is transformed into zones of coil ends of the stator windings and near its end of the core. The influence of the characteristic features of the magnetic field distribution, its energy on the substitution circuit parameters of the low power induction motor and its operating modes are defined. The ratios between the resistances inductive coil ends zone of the stator windings and slots zone stator and rotor windings for an induction motor in short-circuit mode were respectively 14.7% and 85.3%. Originality. The regularities of the spatial distribution of induction and the energy of the magnetic field in the experimental short-circuit mode are defined. When the localization of the magnetic field energy in the frontal parts zone of the stator windings and in the cores and slots regions of the stator and rotor of low-power induction motors, the quantitative relations between the inductive resistances are determined. Practical value. Through the implementation of the dynamic spatial model of electromagnetic fields by the finite element method and numerical simulation data of the short-circuit dynamic mode of the induction motor, the parameters taking into account the structural features of the stator and rotor, and the nonlinear properties of active materials in the multicomponent modeling domain of its substitution circuit are determined. It is proved, that the new approach to the determination of the substitution circuit parameters of induction motors based on simulation data field provides a significant increase in accuracy compared to conventional iterative-empirical methods.

Estimating the parameters of induction motors in different operating regimes from a set of data containing the rotor cage temperature

The purpose of this paper is to propose a method for accurate estimation of the equivalent circuit parameters of induction motors at different operating regimes from a set of measurement data containing the rotor cage temperature and rotor resistance at 25 $$^{\circ }$$ C. Besides these rotor quantities, the method requires the measurement of supply voltage, stator current, frequency, speed, load torque, stator winding temperature and stator winding resistance at 25 $$^{\circ }$$ C. It is assumed that stator leakage reactance, core-loss resistance, friction and windage losses and stray load losses corresponding to the nominal operation are known. The proposed method iteratively determines air gap voltage, power factor and some other parameters. The effects of temperature change, frequency change, magnetic saturation and stray load losses are taken into consideration. The application of the method is discussed within the existing examples of five different motors. Excellent accuracy is achieved using the proposed method.

Low-Intrusive Approach for Parameters Estimation of Induction Motor Using Adaptive Optimal Design Algorithm Based on On-Site Measurements

This paper presents a novel low-intrusive method for estimating the equivalent circuit parameters of induction motor which focuses on a simple means without expensive testing. This paper describes the use of on-site measurements data incorporated with the adaptive optimal design algorithm based on optimization process in order to estimate the best possible set of motor parameters for determining the mechanical output at each measured load. This algorithm includes the feasible boundary of design variables process for evaluating the suitable boundaries of motor parameters depending on its power rating. This proposed method has been verified by the experimental results from four low-voltage TEFC induction motors rated at 2.2, 4.0, 5.5 and 7.5 kW. The results indicate that the agreement between the estimated parameters and the calculated parameters obtained from the standard equivalent circuit method validates the proposed method over a wide range of load conditions. For comparison, the results of estimated mechanical output of actual motors are illustrated. Therefore, this simple procedure can provide the useful information for selecting the motor most suitable for its application

Bio‐inspired optimization algorithms for parameter determination of three‐phase induction motor

PurposeThe aim of this research paper is to examine the bio‐inspired optimization algorithms, namely, genetic algorithm (GA), particle swarm optimization (PSO) and bacterial foraging optimization (BFO) algorithm with adaptive chemotactic step for determining the steady‐state equivalent circuit parameters of the three‐phase induction motor using a set of manufacturer data.Design/methodology/approachThe induction motor parameter determination issue is devised as a nonlinear constrained optimization problem. The nonlinear equations of various quantities (torque, current and power factor) are derived in terms of equivalent circuit parameters from a single and a double‐cage model, and then, equates to the corresponding manufacturer data. These equations are solved by the bio‐inspired algorithms. Using the squared error between the determined and the manufacturer data as the objective function, the parameter determination problem is transferred into an optimization process where the model parameters are determined that minimize the defined objective function. The objective function is iteratively minimized using GA, PSO and BFO techniques. In order to balance the exploration and exploitation searches of the BFO algorithm, an adaptive chemotactic step is utilized.FindingsComparisons of the results of GA, PSO, BFO and IEEE Std. 112‐F (using no‐load, locked‐rotor and stator resistance tests) methods for two sample motors are presented. Results show the superiority of the bio‐inspired optimization algorithms over the classical one. Besides, BFO‐based parameter determination method is observed to obtain better quality solutions quickly than GA and PSO methods.Practical implicationsThe parameters obtained by the proposed approaches can be used in analyzing the stalling and/or reacceleration process of a loaded motor following a fault or during voltage sag condition as well as in system‐level studies.Originality/valueThe most significant contribution of the research is the potential to determine the equivalent circuit parameters of induction motor only from its manufacturer data without conducting any lab tests on the motor. The bio‐inspired optimization based parameter determination approaches are faster and less intrusive than the IEEE Std. 112‐F method.

Determination of induction motor parameters with differential evolution algorithm

In this study, the determination of equivalent circuit parameters of induction motors is carried out with differential evolution algorithm (DEA) and genetic algorithm (GA). As an objective function in the algorithms, the sum torque error at zero speed, pull-out, and rated speed is used. The determination of equivalent circuit parameters is performed with three induction motors of 2.2, 5.5, and 37 kW. In particular, the search ability of DEA is compared with GA by using the same population size, number of iteration, and crossover rate. In addition, the effects of the obtained equivalent circuit parameters on induction motors characteristics are investigated and presented with graphics. The results show that the use of DEA instead of GA increases the convergence sensitivity and reduces the simulation time.

An efficient procedure to calculate equivalent circuit parameter of induction motor using 3-D nonlinear time-stepping finite-element method

This paper presents a procedure to obtain equivalent circuit parameters of induction motors considering skin effect, harmonics, magnetic saturation, movement of the rotor and the end effects of the motor using the three-dimensional (3-D) finite-element method. The 3-D frequency domain analysis is applied in advance to obtain the primary value of the magnetic vector potential. The 3-D nonlinear time-stepping finite-element analysis is carried out with this primary value. A method, which reduces the calculation term by utilizing the symmetry shape of the rotor, is also applied. As a result, we can obtain the whole time-variation of not only the stator, but also the rotor electromagnetic fields at steady rotation with small calculation time.