Three-phase Squirrel-cage Induction Motor Research Articles

Improved Parameter Estimation of Three-Phase Squirrel-Cage Induction Motors Using the Nelder-Mead Simplex Algorithm

This work presents a technique for precisely determining the characteristics of a squirrel-cage three-phase induction motor using the Nelder-Mead simplex algorithm. This approach is a frequently employed numerical optimization technique for determining the minimal value of a multi-dimensional objective function. An advantageous feature of the Nelder-Mead simplex algorithm is its independence from the need to calculate partial derivatives of the objective function. Nevertheless, similar to several optimization techniques, the Nelder-Mead simplex approach can also exhibit sensitivity to the initial conditions. Thus, the initial estimation of the parameters of the approximated equivalent circuit of the induction motor was used as the starting point for the Nelder-Mead optimization approach. The experiment's results are compared to those obtained using the polynomial regression approach to demonstrate the efficacy of the proposed method.

SENSORLESS SPEED ESTIMATION OF THREE PHASE INDUCTION MOTORS BASED ON DYNAMIC MODEL

In speed control systems of induction motor electrical drives, real-time speed monitoring is necessary. Speed monitoring can be done using the direct method, which uses a mechanical sensor mounted on the motor shaft, or the indirect method, which is based on estimation, mainly from the dynamic model of the motor. Speed estimation based on the dynamic model of the motor in orthogonal coordinates is the most widespread method in sensorless speed control systems of three-phase squirrel cage induction motor electrical drives, especially those of high accuracy. This paper presents the open-loop speed estimator used for speed estimation in three-phase induction motors. The proposed speed estimators are based on the orthogonal coordinate’s dynamic model of an induction motor in a stator reference frame. This technical solution is simple and has a low cost. The currents and voltages of the two motor phases are the input variables of the estimator, while the output variable is the induction motor speed. The speed estimator model is built using LabVIEW software. The dynamics and accuracy of the estimator proposed in this paper have been tested experimentally. The speed measured by the industrial incremental encoder is compared with that of a speed estimator modeled in LabVIEW software. The obtained experimental results show a good match between the measured and estimated speeds under the step torque load changes of the induction motor.

Lyapunov-based neural network model predictive control using metaheuristic optimization approach

This research introduces a new technique to control constrained nonlinear systems, named Lyapunov-based neural network model predictive control using a metaheuristic optimization approach. This controller utilizes a feedforward neural network model as a prediction model and employs the driving training based optimization algorithm to resolve the related constrained optimization problem. The proposed controller relies on the simplicity and accuracy of the feedforward neural network model and the convergence speed of the driving training based optimization algorithm. The closed-loop stability of the developed controller is ensured by including the Lyapunov function as a constraint in the cost function. The efficiency of the suggested controller is illustrated by controlling the angular speed of three-phase squirrel cage induction motor. The reached results are contrasted to those of other methods, specifically the fuzzy logic controller optimized by teaching learning-based optimization algorithm, the optimized PID with particle swarm optimization algorithm, the neural network model predictive controller based on particle swarm optimization algorithm, and the neural network model predictive controller using driving training based optimization algorithm. This comparative study showcase that the suggested controller provides good accuracy, quickness and robustness due to the obtained values of the mean absolute error, mean square error root mean square error, enhancement percentage, and computing time in the different simulation cases, and it can be efficiently utilized to control constrained nonlinear systems with fast dynamics.

An integrated 2D/3D numerical methodology to predict the thermal field of electric motors

The present work aims at providing a predictive numerical methodology for the thermal characterization of electric motors. The methodology relies on a 2D-FE simulation for the estimation of the electromagnetic (iron and joule) losses. The latter are then exploited in a 3D-CFD Conjugate Heat Transfer analysis for the evaluation of the thermal field.The CFD model includes both the solid components and the fluid domains. The main novelty of the paper is represented by the copper coil modelling. In fact, copper, air, epoxy resin and enamel are synthetized in a single homogeneous body able to reproduce the thermal behaviour without including the single components, to reduce the computational cost.The methodology is validated against experimental data on a three-phase squirrel-cage induction motor. As for the experimental data (available at three different operating conditions), temperature distributions are measured by thermocouples at the test bench for the validation of the 3D-CFD CHT model. In addition, experimental estimations of the losses are available for the validation of the 2D electromagnetic simulations.The numerical results in terms of motor performance, electromagnetic losses and thermal field are discussed and are proved to be close to the experimental counterparts, for all the investigated conditions.

Mixed Eccentricity Fault Detection for Induction Motors Based on Time Synchronous Averaging of Vibration Signals

This paper presents a method based on vibration signals to diagnose rotor mixed eccentricity faults in three-phase squirrel cage induction motors (SCIMs). Rotor eccentricity is a typical fault in SCIMs that significantly affects the performance of electrical machines and results in unwanted vibrations. The time synchronous averaging (TSA) signal, which consists of the harmonics components generated by the fault, is obtained via the characteristic frequency of the eccentricity fault. TSA is decomposed into two signals: TSA-regular and TSA-difference, which are respectively similar to approximate and details of wavelet transform. Based on the fault index, which is the maximum FFT value of the TSA-difference signal, the healthy and faulty motors can be distinguished. The proposed approach is evaluated on an experimental test rig equipped with a 1.5 kW SCIM supplied directly from the power grid under various load conditions. The results illustrate the effectiveness of the proposed approach in detecting the rotor mixed eccentricity faults.

Thermal Analysis and Cooling Strategies of High-Efficiency Three-Phase Squirrel-Cage Induction Motors—A Review

In recent times, there has been an increased demand for electric vehicles. In this context, the energy management of the electric motor, which are an important constituent of electric vehicles, plays a pivotal role. A lot of research has been conducted on the optimization of heat flow through electric motors, thus reducing the wastage of energy via heat. Futuristic power sources may increasingly rely on cutting-edge innovations like energy harvesting and self-powered induction motors. In this context, effective thermal management techniques are discussed in this paper. Importance was given to the potential energy losses, hotspots, the influence of overheating on the motor efficiency, different cooling strategies, certain experimental approaches, and power control techniques. Two types of thermal analysis computation methods, namely the lumped-parameter circuit method (LPCM) and the finite element method (FEM), are discussed. Also, this paper reviews different cooling strategies. The experimental research showed that the efficiency was greater by 11% with the copper rotor compared to the aluminum rotor. Each rotor type was reviewed based on the temperature rise and efficiency at higher temperatures. The water-cooling method reduced the working temperatures by 39.49% at the end windings, 41.67% at the side windings, and by a huge margin of 56.95% at the yoke of the induction motor compared to the air-cooling method; hence, the water-cooling method is better. Lastly, modern cooling strategies are proposed to provide an effective thermal management solution for squirrel-cage induction motors.

Induction Motor Vibrations Caused by Mechanical and Magnetic Rotor Eccentricity

Vibration reduction of induction motors is a significant problem that requires effective models for the effects of mechanical and electromagnetic unbalanced forces. This article presents a mathematical model of dynamics for induction motors with rotor mass eccentricity and static and dynamic magnetic eccentricity. The model allows for the influence of the gyroscopic torque of the rotor and considers the elastic-damping characteristics of each of the stator supports and their location. The model has eight degrees of freedom, which makes it possible to simulate transverse and axial vibrations of various designs’ rotors and housings of induction motors. The results of modeling the dynamics for a three-phase squirrel cage induction motor with 11 kW capacity agreed with those obtained by other authors. Simultaneously, new results were also obtained within the research. The simulation results showed that the static magnetic eccentricity causes the appearance of additional critical speed of the motor, and its value decreases in proportion to the growth of the number of pole pairs. The change of the moment of inertia of the motor at a mismatch of the main axis of symmetry of the stator and the rotor axis of rotation allowed for obtaining an actual frequency spectrum of free oscillations, including the rotational motion of the stator. Since the actual static magnetic eccentricity can additionally increase at operating frequencies due to the increase of bearing clearance caused by dynamic unbalanced load, it should be considered in the analysis of unbalanced magnetic pull. The angle of static magnetic eccentricity significantly affects the magnitude of radial vibrations. This feature should also be considered when selecting the locations of balancing weights during the rotor balancing procedure.

Control of Three-Phase Squirrel Cage Induction Motor by Field Acceleration Method (FAM) for E-Mobility

The rapid electrification of mobility systems has fuelled the demand for advanced control techniques that can enhance the performance and efficiency of electric vehicles (EVs). In this context, this paper introduces the Field Acceleration Method (FAM) as a control strategy for three-phase squirrel cage induction motors, specifically tailored for e-mobility applications. FAM has not been previously simulated or tested practically in the context of electric mobility, making this study a pioneering effort. Induction motors are widely employed in electric vehicles, and various control methods such as the Indirect Field-Oriented Control (IFOC) gained popularity for its effectiveness in achieving precise and efficient motor control. In this research, FAM is simulated using MATLAB, and the results demonstrate its suitability for electric vehicle control applications. FAM exhibits the potential to achieve rapid speed responses, making it a promising alternative to established control techniques. The outcomes of this study highlight the applicability of FAM in improving the dynamic performance of EVs, contributing to the ongoing efforts to enhance the efficiency and responsiveness of electric mobility solutions. This research paves the way for practical implementations of FAM in electric vehicles, potentially revolutionizing the field of EV motor control.

Mathematical Modeling of a Three-Phase Induction Motor Fed by a Photovoltaic System

This paper presents the mathematical modeling of the three-phase squirrel cage induction motor and its driver, the DC bus, and a photovoltaic system comprised of photovoltaic cells and the DC/DC boost converter. The mathematical modeling is accomplished in two manners, using the laws of Physics and the Euler-Lagrange approach. In addition, the mathematical modeling also considers the 𝒂𝒃𝒄 and 𝒒𝒅𝟎 reference frames. The mathematical models are validated through simulation in the Matlab/Simulink environment, programming the obtained equations and comparing them with a block model of the simulation environment.

Derating of Squirrel-Cage Induction Motors Due to High Harmonics in Supply Voltage

This paper presents the results of load capacity calculations for three-phase squirrel-cage induction motors supplied with distorted voltage with rotating harmonics. The calculations were made on the basis of a commonly used model of an induction machine. The difference from many papers is that the parameters of the equivalent circuit of each motor were precisely determined in terms of power losses in the motor. The load capacity of the motors was made dependent on the load power losses in the rotor cage. These losses were determined on the basis of short-circuit measurements of motors, made for frequencies equal to harmonic frequencies. Measurements and calculations were made for low-voltage squirrel-cage motors with rated powers of 4–65 kW and various efficiency classes. Calculations have shown that the calculated derating curves do not match the curves given in IEC 60034-17 and NEMA MG1. The differences are up to 15% for IE1 and IE2 motors and more than 50% for IE3 motors.

Reduction and control of harmonic on three-phase squirrel cage induction motors with voltage source inverter (VSI) using ANN-grasshopper optimization shunt active filters (ANN-GOSAF)

Reduction and control of harmonic on three-phase squirrel cage induction motors with voltage source inverter (VSI) using ANN-grasshopper optimization shunt active filters (ANN-GOSAF)

Modeling and Control of an Air Conditioner Powered by PV Energy and the Grid Using a DC Microgrid

This paper presents the mathematical modeling and control design procedure of the compressor motor of an air conditioner using the energy from a photovoltaic system combined with the power grid in a DC microgrid. A comprehensive model considers the interconnection of the photovoltaic cells with their associated DC/DC converter, the DC bus, the three-phase squirrel-cage induction motor with its driver, the bidirectional DC/AC converter, the output filter, and the power grid. The state-of-the-art showed that a complete mathematical model of the proposed system is unavailable. Therefore, the mathematical model of the system is compared and validated in simulation with a block diagram in the Matlab/Simulink environment. In addition, several control approaches are used in the whole system to track the maximum power point of the photovoltaic cells, obtain a soft start on the machine, control the velocity using the variable frequency drive, regulate the DC bus voltage, and manage the power flow between the DC bus and the power grid.

Derived Functions for MATLAB Non-linear Solvers – an optimal Stator Slot Design Stopgap

In the three-phase squirrel cage induction motor (SCIM), like other rotating electromechanical machines, the active length of the stator windings lies in the slots. The proper dimensioning of the slots is therefore critical to the design of both the windings and the stator core, so as to attain a high performing machine. The preliminary stage of the SCIM design, if well done, facilitates the refinement and optimization stages; serving as a good take-off point for that final state of the art design. The aim of this article isn’t to come up with a novel optimization method for the SCIM, but to provide another way of obtaining an initial stator slot design template, from where proper design refinement/optimization techniques could obtain very good starting values and be facilitated. Therefore, an attempt is being made here to derive relevant design functions that could be fed into the algorithms of various non-linear solvers such as the Genetic Algorithm (GA), to output the main stator slot dimensions for the SCIM. The final designed SCIM obtained from implementing the derived equations, when compared with the appropriate reference datasheets, showed only minor deviations from the expected performance indices – an outcome deemed satisfactory for a preliminary design attempt. These initial dimensions may in practice be subjected to the appropriate refinement. Depending on the target performance requirement of the motor.

A study of the dependence of the 3-phase cage motor maximum torque on the centroid of the rotor bar section

The paper investigates the relative influence of the centroid of the three-phase squirrel cage induction motor rotor bar cross section, on the breakdown (maximum) torque of the machine. The influence of the angle of taper, the top width and the radial depth of the bar section, as established design variables, were also investigated so as to properly situate the degree of influence of the centroid, in comparison; as far as the maximum torque is concerned. The machines were investigated in their steady state operating mode using the equivalent circuit method. The machine learning capabilities of the Least Square Support Vector Machine (LSSVM) was deployed to extract by prediction, information about the likely dependencies between the randomized block of the geometric variables and the maximum torque, and the captured information was stored using the Root Mean Square Error (RMSE) of predictions. The validated results show that the rotor leakage reactance – a part determinant of the maximum torque; tends to show some significant sensitivity to a design change in the centroid of the transverse section of the rotor bar.

Hybrid Backstepping-Super Twisting Algorithm for Robust Speed Control of a Three-Phase Induction Motor

This paper proposes a Hybrid Backstepping Super Twisting Algorithm for robust speed control of a three-phase Induction Motor in the presence of load torque uncertainties. First of all, a three-phase squirrel cage Induction Motor is modeled in MATLAB/Simulink. This is then followed by the design of different non-linear controllers, such as sliding mode control (SMC), super twisting SMC, and backstepping control. Furthermore, a novel controller is designed by the synergy of two methods, such as backstepping and super twisting SMC (Back-STC), to obtain the benefits of both techniques and, thereby, improve robustness. The sigmoid function is used with an exact differentiator to minimize the high-speed discontinuities present in the input channel. The efficacy of this novel design and its performance were evidenced in comparison with other methods, carried out by simulations in MATLAB/Simulink. Regression parameters, such as ISE (Integral Square error), IAE (Integral Absolute error) and ITAE (Integral Time Absolute error), were calculated in three different modes of operation: SSM (Start-Stop Mode), NOM (Normal Operation Mode) and DRM (Disturbance Rejection Mode). In the end, the numerical values of the regression parameters were quantitatively analyzed to draw conclusions regarding the tracking performance and robustness of the implemented non-linear control techniques.

Derating of Squirrel-Cage Induction Motor Due to Rotating Harmonics in Power Voltage Supply

This paper presents a method for determining the load capacity of three-phase squirrel-cage induction motors supplied with a balanced distorted voltage containing rotating harmonics (1st, 5th, 7th, 11th, 13th,...). The method is based on the dependence of the motor load capacity on the load power losses in the rotor cage. The load capacity was determined based on motor short-circuit measurements made for frequencies equal to harmonic frequencies. To evaluate the load capacity, a factor with the proposed name Harmonic Losses Factor (HLF) was introduced. Its expression is a generalization of the well-known HVF expression. However, it has been shown that a more accurate estimation of the load capacity is obtained using the sum of load power losses in the rotor cage from higher harmonics. Measurements and calculations were carried out for a low-voltage squirrel-cage motor with a rated power of 22 kW and a synchronous speed of 1500 rpm. Calculations showed that the derating power curves given in the IEC 60034-17 and NEMA MG1 standards are incorrect for the tested motor.

Design of Sliding Mode Control using SVPWM Modulation Method for Speed Control of Induction Motor

The sliding mode control method is a highly accurate and easy-to-implement approach that can be effectively utilized in the control of high-dimensional nonlinear systems that operate under uncertain conditions. In this study based on Matlab/Simulink, a Proportional-Integral-Integral Sliding Mode Control (PI-ISMC) method has been developed to control the mechanical speed of a three-phase squirrel cage induction motor. The modeling of the induction motor and the design of the proposed controller have been conducted in the qd0 reference frame. The asymptotic speed tracking under uncertainty and different loading conditions has been ensured by tuning the parameters of the PI-ISMC controller. Additionally, field-oriented control (FOC) with space vector modulation has been applied to the same motor to evaluate the performance of the sliding mode control topology in induction motor control, and its performance has been compared with the sliding mode control method.

Real-Time Investigation of Temperature Effect on Induction Motor Equivalent Circuit Parameter Change

Today’s developing technology and increasing demands in production areas continue the importance of studies on induction motors (IMs). To meet the demands, the mathematical modeling of IMs must be performed fully and accurately. Variable conditions cause changes in many electrical, magnetic, and thermal parameters. A change in parameters affects the intensity, efficiency of the operating currents of the machine, thereby changing the motor losses. In this article, the objective is to determine the changes in the equivalent circuit parameters of three-phase squirrel-cage induction motors (SCIMs) with different powers under the variable conditions (stator winding temperature, load, and motor shaft speed). Supervisory control and data acquisition (SCADA) program read real-time information (temperature, current, voltage, power, shaft speed, and torque) from the experiments and necessary calculations were made. When the test results were examined, a maximum of 9 % change was observed in the motor ECPs (RS, R2, RM, XS, X2, and XM) at different shaft speeds as a result of the change in the stator winding temperature between 100 % and 110 %. At different loads, this rate of change increases to 16 %. This has shown that motor shaft speed and load, together with temperature, have a significant effect on the ECPs.

Performance Prediction of Induction Motor Due to Rotor Slot Shape Change Using Convolution Neural Network

We propose a method to predict performance variables according to the rotor slot shape of a three-phase squirrel cage induction motor using a convolution neural network (CNN) algorithm suitable for utilizing image data. The set of performance variables was labeled according to the images of each training dataset, and this set was generated from the efficiency, power factor, starting torque, and average torque. To verify the accuracy of the trained deep learning model, the analysis and prediction results of the CNN model were compared and verified with nine untrained double cage slot shapes and shapes optimized based on the root mean square error (RMSE). Although a large number of training data are required for high accuracy in the existing image processing deep learning model, the proposed deep learning method can predict the performance variables for various shapes with the same level of accuracy as the finite element analysis results using a small number of training data. Therefore, it is expected to be applied in various engineering fields.

Optimization of Energy Efficiency of Three Phase Induction Motor Drives for Industrial Applications

Electric motors are used in nearly 60% of the global electrical power generated. Due to the greater energy consumption, there has been a considerable rise in production costs and environmental degradation, increasing general operating expenses. Therefore, the efficiency of three-phase squirrel cage induction motors (SCIMs) may be improved to save a large amount of electricity. The thesis aims to investigate increasing the efficiency of three-phase (SCIM). The proposed method improves the efficiency of (SCIMs) using PID controller Simulink design in Simulink/MATLAB. To successfully determine the motor characteristics and simulate a three-phase (SCIM) under various loads. The effects of lowering the voltage and using PID controller on motor characteristics such as generated torque, power factor, reactive power, apparent power, output power, rotor speed, and magnetising current are also discussed. The simulation result found that the proposed motor efficiency and power factor method is improved by using a PID controller. At motor torque of 12 N-m, the efficiency is 80%, which rises to 92 % at higher motor torques. After applying the proposed method, the power factor becomes 0.64%, which is an improvement of 0.2%.