Energy Efficiency Of Induction Motors Research Articles

Energy Efficiency of Induction Motor Drives: State of the Art, Analysis and Recommendations

Despite activities to introduce low-carbon energy sources worldwide, the share of conventional facilities burning organic fuels remains high. One approach to address this problem is to look for solutions to reduce energy consumption. There are various research projects in the area of energy efficiency that lead to diverse results—such as models, methodologies, new data and theories. On the other hand, induction motor drives are becoming a major consumer of electric power because of their wide range of applications. In this paper, after careful selection and systematization of 151 literature sources, an extensive study and criteria analysis of the existing state of affairs in the area of energy efficiency improvement of induction motor drives has been carried out. Five major and 48 minor research areas in this field have been identified. The results show that issues related to the adaptation of scientific results and the conditions for their effective and wide-ranging application in practice have not been discussed and investigated so far. Adaptation should take into account the possibilities of data acquisition, including data from measurements; the competences of energy managers; and the type of information provided to them. Based on the seven conclusions formulated below, summary recommendations are made to direct future research towards the justification of models for increasing the power efficiency of induction drives, adapted for use by energy managers.

Geometry influence of stator and rotor armatures on energy efficiency of induction motors

This paper presents the geometry influence of stator and rotor armatures on induction motor energy efficiency. The entire work is analyzed using a Motor-CAD programming environment. In principle, in the first stage, the influence of each armature is distinctly visualized upon loss level, for given effective power and given cooling algorithm through geometry changes that concern aspects related to the dimensions of the ferromagnetic core and the notches practiced within it. Afterwards, in a second stage, a synergistic modification of the induction motor geometry is carried out by cumulating the changes (cooperative effect) at the level of the two armatures, aiming to find the topology that provides – for some given effective power, and cooling algorithm – the highest energy efficiency.

Особливості розрахунку характеристик компенсованого асинхронного двигуна в програмному середовищі matlab simulink

An asynchronous electric motor with a short-circuited rotor is the most common means of converting electrical energy into mechanical energy in the electric drive of working machines in industry and agriculture. Modern methods of increasing the energy efficiency of induction motors with short-circuited rotor are aimed at finding with the help of computer technology the optimal solutions in the processes of their design, production and operation using new high-performance materials in machines. Such methods do not change the physical processes occurring in the induction motor, ie are passive. However, despite numerous improvements and scientific achievements, technical and economic indicators of induction motors still do not meet modern energy requirements. It is necessary to use ways to increase the energy efficiency of induction motors while maintaining their simplicity and reliability. It is proposed to use internal capacitive compensation of reactive power of induction motors. The aim of the research is to develop a mathematical model of an induction motor with internal capacitive reactive power compensation in the MathLab Simulink software environment for the calculation of operating and mechanical characteristics. A mathematical model of an induction motor with internal capacitive reactive power compensation in the MathLab Simulink software environment using the theory of electric circuits has been developed. The developed mathematical model allows to study the working and mechanical characteristics of an induction motor with internal capacitive compensation of reactive power. Numerical researches of characteristics of the induction motor with internal capacitive compensation of reactive power are carried out and their comparison with corresponding characteristics of the basic induction motor is carried out.

Variable Voltage Control of Three-Phase Induction Motor for Energy Saving

Energy saving is one of the most important factor for industrial and commercial applications. In the industries, Induction motors are the mostly preferred due to their reliability, robustness, price and rugged construction. The largest percentage of consumed energy in industrial is consumed by induction motors. So, Energy conservation in induction motor drive leads to reduction in power consumption and electricity cost. This paper describes energy saving technique for squirrel cage induction motor. The energy saving is achieved by controlling the voltage applied to the stator winding using the three phase AC voltage controller. The simulation verifications are done in MATLAB/Simulink. The results show that the proposed scheme gives rise to the considerable energy-savings The rated efficiency of an induction motor is high when it operates under the full load. In general, the rated efficiency is larger than 75%. Although, the operating efficiency of the induction motor drive system will be low if an induction motor is operating at light loads or does not selected correctly. So, that the improvement in the energy efficiency of induction motor drives refers to huge energy saving

Comparison of Analytical and Software Based Design of Energy Efficient Induction Motor

Energy Efficient Induction motor is playing a vital role in current scenario. Due to rising electrical energy demand, increased awareness of global warming, and rising fossil fuel prices, energy efficiency has become increasingly important. Apart from adding capacity, the only practical approach to deal with this situation is to make optimal use of the available energy, which may be done by using energy efficient Motors. The main objective of this paper is to calculate and Compare the Analytical and Electromagnetic Software based design for a 5HP Energy Efficient Motor.

Direct torque control versus indirect field-oriented control of induction motors for electric vehicle applications

Performance and energy efficiency of induction motors (IM) used in electric vehicle (EV), by applying two control methods, namely the indirect field-oriented control (IFOC) method andthe direct torque control (DTC) method, are compared.The tracking accuracy under changing vehicle speed circumstances for different speed controllers (classical PI, fuzzy logic, and sliding mode speed controllers) is studied. The EV including IM and battery is considered a nonlinear system. For modelling and simulation of EV components and for evaluating the controller performances, a Matlab m-file code package based only m-file coding is developed. The simulations reveal the advantage of DTC over IFOC and the superiority of the proposed sliding mode controller, in terms of improved tracking accuracy and increasing energy efficiency, and motivate the use of the proposed sliding mode controller for EV applications.

Safe operation of Induction Motor with Programmable Logic Controller and Human Machine Interface

Energy efficiency of Induction motor (IM) is essential in the current scenario due to the reasons such as energy conservation and economic saving. In this project, the implementation of the safe speed control of IM is done. The Programmable Logic Controller (PLC) monitors the speed and trips the motor under safety requirements. PLC is used to control three phase IM with the Variable Frequency Drive (VFD). The availability of drive data and software helps to manipulate and analyze process the information. The Human Machine Interface (HMI) is used for the visual monitoring and control of the induction motor. The PLC based control platform makes system to be communicated to other devices on network and makes the system more flexible for its operation and control. The results shows that, the speed of the induction motor varies linearly with the change in frequency in HMI and the motor trips if there is any human interference within 10 cm operating range of IM.

Load extrapolation computational algorithms for energy efficiency measurement testing of high‐power and high‐voltage induction motors

This paper deals with load extrapolation methods and algorithms for the estimation of the energy efficiency of induction motors, starting from the electrical data generally available after parameter identification. The main aim of this paper is to help the readers move from the theoretical analysis to the experimental verification, which is suitable to be included in its own testing. For this reason, step‐by‐step algorithms are included in this paper. The first part deals with the determination of energy efficiency based on an original load extrapolation. Finally, experimental verification of the high‐power and high‐voltage induction motors is provided. Comparison between the values of the in–out method and load extrapolation method confirms the validity of the proposed algorithms. Compared to the direct in–out method, the error of the load extrapolation proposed in this paper is less than 1%.The load extrapolation method is mainly used for the high‐voltage and high‐power asynchronous motor. The high‐voltage and high‐power motor can be used to drive a low‐power motor to achieve coaxial twin trawling in the absence of a suitable power supply and matched load. The energy efficiency of a high‐power motor under different loads are measured and estimated using a mathematical fitting method. The estimated energy efficiency curves in the whole load range can be used to evaluate the high‐power and high‐voltage induction motor. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Assessment of the energy efficiency estimation methods on induction motors considering real-time monitoring

Different methods have been developed to estimate the energy efficiency of induction motors. The accuracy of these methods vary with the load factor, the unbalanced voltage (UV) and harmonics. The feasibility of these methods for efficiency estimation in real-time were theoretically and experimentally assessed during the operation under different operational conditions (i.e. balanced sinusoidal voltage (BSV), harmonics, UV and harmonics with UV). Results show that for load factors over 80%, the air-gap method is applicable under any condition, while the slip method is only applicable under BSV or balanced harmonic voltage. Moreover, for load factors over 40%, the nameplate method is applicable under BSV. Other methods result in errors over 8% and optimization methods are not applicable for real-time monitoring. Electric systems generally operates with some degree of UV and harmonics, while induction motors mostly operate with load factors below 60%, limiting the use of these methods for real-time measurement.

Three autoregressive-neural network hybrid models for energy efficiency estimation of induction motors

PurposeImprovements on the energy efficiency of the induction motors bear on not only these motors but also on the whole industry as a result of preference of these types of motors. In recent projects, energy efficiency of the induction motors is approaching to 90 per cent. The first necessary condition of the efficiency improvements is an accurate estimation of energy efficiency. This study aims to estimate the energy efficiency of induction motors by using three innovative estimation methods.Design/methodology/approachData for 307 motors were taken from three different companies and their torque, power, power factor and speed data were used. Three hybrid models were created by estimating the error of three autoregressive (AR)-based efficiency estimation models with the back-propagation artificial neural network (ANN) structure. In these proposed hybrid models, the AR models were supported with artificial neural networks to obtain a minimum estimation error. These three hybrid models were called as AR1-ANN, AR4-ANN and residual-ANN.FindingsWithout hybridization of AR models by back-propagation ANNs, the best estimation result was obtained by residual model. On the other hand, for the proposed hybrid models, the best estimation was obtained by AR1-ANN, followed by AR4-ANN and finally the residual-ANN according to ME values.Practical implicationsProposed AR-ANN hybrid models relieve of longtime experiments for the energy efficiency measurement of induction motors. Furthermore, these AR-ANN models give more accurate results than the available methods in the literature. Engineering value of this research is three different issues in finding energy efficiency. The first one is minimizing of the test cost, the second one is no requirement the test equipment and the third one is not interrupting the motor. Every company that needs motors can use these estimation methods due to the advantages.Originality/valueNovel three AR-ANN hybrid models for energy efficiency estimation were studied. These novel methods give better response than the other methods which were used for estimation of induction motors in the literature.

Erratum to: “An Energy-Efficient Induction Motor with an Unconventional Electromagnetic Core”

The list of author’s affiliations should read as follows: a Samara State Technical University, Samara, 443100 Russia b National Research University Moscow Power Engineering Institute, Moscow, 111250 Russia

A New Field Test Method for Determining Energy Efficiency of Induction Motor

Electric motors and the drive systems approximately consume half of the global electricity consumption. In the European Union (EU), electric motors and the drive systems are estimated to account for about 70% of all industrial electricity consumption. Therefore, mandatory applications accrue from the legislation of governments or unions like the EU for customs and market surveillance or eco-design requirements. The mandatory applications and the global market size find out the necessity of efficiency measurement. There are several compliance and precompliance efficiency test methods in the literature. The compliance tests should execute reliable, accurate, and reproducible results. The purpose of this paper is to define a simple field method that will be used for measuring and determining in-service efficiency at industrial conditions. The proposed method in this paper is an inexpensive and easy method that would help to energy managers and engineers to make correct decision in replacing inefficient motors with efficient and new ones. In this paper, a novel induction motor-efficiency model function has been proposed based on the International Electrotechnical Commission 60034-2-1 standard equations, and a new field test procedure has been used in efficiency estimation. The new efficiency model function variables and constants are determined from the regression analysis, which depends on 86 tests of 437 different load points’ efficiency data. Furthermore, the proposed field test procedure, equations, and compliance test methods are tested on a sample motor in laboratory, and the results are compared to each other.

Energy Efficient Control of an Induction Machine Under Torque Step Changes

Methods for increasing the energy efficiency of induction motors by an appropriate control strategy have been a subject of research during the last years. Several methods for loss minimization have been developed for induction motors operated in a steady state. In recent years, some solutions for the dynamic case have been given as well either using an online or offline optimization approach, implying a certain computational burden, which is undesired in practice. This paper shows that the appropriate application of steady state techniques during transients due to a changing motor torque is a suboptimal strategy with an acceptable performance for efficiency optimization given an induction machine where saturation effects of the main inductance must be considered. The optimization problem is simplified such that a simple suboptimal solution is possible and the quality of the suboptimal solution is investigated by simulations and measurements. The proposed solution is simple, easy to implement, and does not require an online optimization. In addition, the influence of magnetizing induction saturation is considered.

New criteria for energy efficiency of induction motors with squirrel-cage rotor winding

New criteria for energy efficiency of induction motors with squirrel-cage rotor winding

Технология реконструкции традиционных асинхронных двигателей на энергосберегающие варианты

Shows the low energy efficiency of induction motors, because of the low power factor. Proposed during overhaul traditional induction motors perform their reconstruction to energy saving variants. The reconstruction is performed by changing the design of the stator windings and the use of individual compensation capacitors. Improving energy efficiency ensured by the reactive power compensation and achievement cos?=1. Proposed the process flowsheet for Reconstruction. The scheme provides new operations: recalculation the parameters of the motor stator windings and calculation capacity of the compensating capacitor; computer modeling work and mechanical characteristics; laying the work stator windings and the compensation stator windings; express withdrawal the experimental work and the mechanical characteristics of the oscilloscope traces on starting, reversing and braking the induction motor without load using special hardware and software system. Every kilowatt installed power of the reconstructed energy-efficient motor saves energy from 350 to 750 kW ? h per year.

Non Invasive Sensors for Monitoring the Efficiency of AC Electrical Rotating Machines

This paper presents a non invasive method for estimating the energy efficiency of induction motors used in industrial applications. This method is innovative because it is only based on the measurement of the external field emitted by the motor. The paper describes the sensors used, how they should be placed around the machine in order to decouple the external field components generated by both the air gap flux and the winding end-windings. The study emphasizes the influence of the eddy currents flowing in the yoke frame on the sensor position. A method to estimate the torque from the external field use is proposed. The measurements are transmitted by a wireless module (Zig-Bee) and they are centralized and stored on a PC computer.

Design optimization of three‐phase energy efficient induction motor using adaptive bacterial foraging algorithm

PurposeThe purpose of this paper is to present the application of an adaptive bacterial foraging (BF) algorithm for the design optimization of an energy efficient induction motor.Design/methodology/approachThe induction motor design problem is formulated as a mixed integer nonlinear optimization problem. A set of nine independent variables is selected, and to make the machine feasible and practically acceptable, six constraints are imposed on the design. Two different objective functions are considered, namely, the annual active material cost, and the sum of the annual active material cost, annual cost of the active power loss of the motor and annual energy cost required to supply such power loss. A new adaptive BF algorithm is used for solving the optimization problem. A generic penalty function method, which does not require any penalty coefficient, is employed for constraint handling.FindingsThe adaptive BF algorithm is validated for two sample motors and benchmarked with the genetic algorithm, particle swarm optimization, simple BF algorithm, and conventional design methods. The results show that the proposed algorithm outperforms the other methods in both the solution quality and convergence rate. The annual cost of the induction motor is remarkably reduced when designed on the basis of minimizing its annual total cost, instead of minimizing its material cost only.Originality/valueTo the best of the knowledge, none of the existing work has applied the BF algorithms for electrical machine design problems. Therefore, the solution to this problem constitutes the main contribution of the paper. According to the huge number of induction motors operating all over the world, the BF techniques used in their design, on minimum annual cost basis, will lead to a tremendous saving in global energy consumption.

Application of stochastic method to optimum design of energy-efficient induction motors with a target of LCC

For an energy-efficient induction machine, the life-cycle cost (LCC) usually is the most important index to the consumer. With this target, the optimization design of a motor is a complex nonlinear problem with constraints. To solve the problem, the authors introduce a united random algorithm. At first, the problem is divided into two parts, the optimal rotor slots and the optimization of other dimensions. Before optimizing the rotor slots with genetic algorithm (GA), the second part is solved with TABU algorithm to simplify the problem. The numerical results showed that this method is better than the method using a traditional algorithm.

Improving three-phase induction motor efficiency in Europe

An overview of the efficiencies of present-day induction motors manufactured in Europe is given. An illustration of the impact of improving induction motor efficiency as a factor in reducing energy consumption in the EU is also given. In addition the 'Hi-motors' (energy efficient induction motors) competition for motor manufacturers is described. The competition was launched on the Internet and with direct mailing activities on 24th June 1997 and the closing date for the opening round of the competition is the 15th August 1998. Manufacturers are invited to send in test reports of prototype(s) or production version(s) of highly energy efficient induction motors. The competition will cover three-phase squirrel cage induction motors for general-purpose continuous operation applications in the range from 0.18 to 110 kW.

Energy-efficient induction motors performance characteristics and life-cycle cost comparisons for centrifugal loads

When fixed-speed motors (fed directly at power frequency) are purchased for new installations or for replacements, an aspect either ignored or overestimated is the loaded shaft speed differences among motor options. The most common first-cut estimate is that the consumed shaft power will vary as the cube of the ratio of the motor rated nameplate speeds for centrifugal driven loads that have discharge valves (on pressure or flow control). This is true only if the motors are loaded at approximately their nameplate output. This paper discusses the true control valve factor, taking into account actual speed differences among motor options. A simplified equation and figure are presented to permit quick evaluation of motor purchase alternatives for lowest life-cycle cost based on efficiency and rated-load speed differences. NEMA standards on slip-speed variation should be made more stringent to make speed-difference loss evaluations more valid. Additionally, efficiency test results and loaded speed measurements for standard efficiency and premium efficiency 10 hp and 100 hp motors are presented, leading to a conclusion that standard efficiency motors should be operated at no higher than rated voltage and that lower rated premium efficiency motors should be operated at 5% to 10% above rated voltage for best system efficiency.