Energy Efficient Motors Research Articles

Economic Barriers to the Application of Energy Efficient Motors in Industry

In this paper we present a technical, economic and financial feasibility analysis of the replacement a standard-efficiency induction motor (IE1) by a Premium-efficiency induction motor (IE3) in an industrial application. We consider a press used for the production of crude degummed soybean oil and soybean expeller, from an industry in the Province of Cordoba, Argentina. We use a model of the induction motor that drives the press to correctly estimate the load level and the performance of the induction motor currently used. With the data obtained from the model, we analyze the economic and financial feasibility of the induction motor replacement for the registered operating conditions, with the current energy prices and the associated subsidies. We calculate different indicators for the current scenario and future forecasts. The results show that, in the current context of high interest rates and high subsidies to electric power, economic barriers may exist to the replacement of induction motors by the higher efficiency class. However, the analysis with future scenarios of lower subsidies for electric power and / or lower interest rates on financial income can cause these barriers to be removed.

Direct Torque Model Predictive Control of a Five-Phase Permanent Magnet Synchronous Motor

Polyphase permanent magnet synchronous motors exhibit outstanding advantages over the traditional three-phase traction motors in electrified transportation applications. This article introduces a novel direct torque model predictive control technique aiming at developing a highly reliable, loss-minimizing, and energy-efficient five-phase permanent magnet synchronous motor drive. Leveraging the underlying constrained optimization process, the direct torque model predictive control approach optimizes the torque delivery and speed regulation quality, improves the flux and torque ripples, reduces higher order current harmonics, minimizes motor drive losses, and boosts power efficiency of the electric powertrain. dSPACE DS1104 hardware-in-the-loop and computer simulation studies are jointly utilized to verify the effectiveness and robustness of the proposed direct torque model predictive control approach in polyphase permanent magnet synchronous motor drive applications.

IEC61800-9 System Standards as a Tool to Boost the Efficiency of Electric Motor Driven Systems Worldwide

Recognition of the energy savings potential in motor driven systems has led to the development of energy efficiency testing and classification standards for motors and end-use equipment (e.g., pumps and fans) and the implementation of minimum energy performance regulations targeting them worldwide. However, these standards and regulations have been limited to components, disregarding the interaction between them. The energy savings achievable by addressing and improving the entire system are potentially much higher in relation to those achievable when considering individual components. Recently, an effort to develop standards in this regard was carried out by standardization bodies (IEC and ISO) leading to the publication of the IEC61800-9 Power Drive System standard series. The paper, in its first part, describes recent evolutions in electric motor energy-efficiency standards and in the implementation of related regulations worldwide. In the second part of the paper, using the latest energy efficiency test and classification standards, a comparative analysis of different energy-efficient motor technologies is presented. Using results from laboratory tests combined with data provided by manufacturers, different power drive systems are compared considering different operating points in two typical pumping systems. Estimated economic savings from a total cost of ownership perspective are presented.

Energy efficient design of three phase induction motor by water cycle algorithm

Abstract The demand for electricity is growing very fast; as a result, the entire power sector is facing a real problem of meeting the additional demand. Rigorous energy audit suggests the replacement of energy-efficient devices from standard one, operating with poor efficiency and consumes large power. 3-phase induction motor is widely used as driving power in most of the industries and it consumes almost 65% of the total power. The energy-efficient design of such motors saves a considerable amount of energy and reduces the cost of operation. In this paper, an attempt has been made to design energy-efficient induction motor from different perspective of using design and optimization without high-quality material. In this paper, the cost of yearly energy losses is considered as objective function and it is optimized to save energy and money as well. The design problem is a nonlinear constraint optimization problem, which involves many variables and constraints. Water Cycle Algorithm (WCA) is one of the most recently developed metaheuristic algorithm is taken for the optimization for the case study of 5 HP and 10 HP, 3- phase, Squirrel cage induction motor. The objective function is optimized by WCA and Genetic Algorithm and their result is compared for accuracy from cost and performance point of view. WCA found to be the most efficient tool to optimize the problem and helps to design an energy-efficient motor.

An assessment of energy efficient motors application by scenarios evaluation

The choice of the most appropriate public policies to foster energy efficiency measures often is a difficult task due to the large number of intervening variables and agents and, also, high levels of uncertainties in estimating the corresponding energy savings. This paper presents a methodology that builds up scenarios to assess the impacts on energy consumption of introducing different levels of penetration of efficient electric induction motors, according to the set of policies and measures adopted in the scenarios. The proposed methodology comprises three modules. The first one selects strategic objectives, key variables and control players, determines their direct and cross-influence levels, based on the opinions of consulted experts, and sets up some scenarios combining them. The second module carries out electric motor sales forecasts based on electricity consumption forecasts for the industry. The third module estimates the energy saving forecasts associated to each scenario. The approach is applied to Brazil in the paper, indicating valuable policy options and their likelihood to local decision makers and other stakeholders.

An Economic Analysis of Rewind, Premium, and Standard Efficiency Vertical Hollow Shaft Motors for Irrigation

Abstract. Vertical hollow shaft motors are commonly used for vertical turbine pumps for irrigation. They are a specialty motor which has been exempt from the Department of Energy (DOE) requirement for improved energy efficiency. We evaluated the payback and net present value (NPV) of standard efficiency, energy efficient, and premium efficiency motors for motor sizes used in irrigation. For motor sizes between 22 and 56 kW (30 and 75 hp), the NPV and payback analysis indicated that premium efficient motors are more advantageous than standard efficiency. In motor sizes greater than 75 kW (100 hp) standard efficient motors are more cost effective than replacing a motor with a premium efficiency motor. When considering a repair or rewind of a motor, the result is highly dependent on the quality, and the resulting efficiency expected after the repair. If a repaired motor nameplate efficiency could be attained after rewinding and repair, then rewinding is most cost effective. However, if original nameplate efficiency is not attained, then it may be more cost effective to purchase a premium efficiency motor over rewinding. New DOE requirements may be advantageous for irrigators even though capital costs will be higher for new motors. Keywords: Motor rewind, Net present value (NPV), Payback period, Premium efficiency motor.

Solution of optimization problems of high-inertial asynchronous electric drive

The method of optimum start-up calculation on computer with use of the principle of a maximum and Newton-Rafson's method for the high-inertial asynchronous electric drive is offered. Based on this technique, optimal dynamic modes of high-inertia frequency-controlled asynchronous electric drive are calculated taking into account thermal processes. Methods of increasing electric motor energy efficiency due to reducing power consumption in dynamic modes are considered.

Energy Conservation and Efficiency by Energy Efficient Motor in India

Electricity demand in India is increasing at a rapid pace because of growth in Economy, urbanization, infrastructure development and the living standard of people. According to the United Nation’s world population prospects (2017), India’s population is 1.34 billion which will go grow further and surpass China by 2025[1]. According to the IMF, the Indian economy is expected to grow by 7.5% in FY19-20 and 7.7% in FY20-21[2]. Increased population and growth in GDP are associated with increased energy demand. India’s primary energy consumption was 754 Mtoe in 2017 and expected to reach 1928 Mtoe in 2040[3]. Major energy demand is from the Industrial sector which was 51% of total primary energy consumption in 2017 and expected to reach 990 Mtoe, by 2040 [3]. Rising energy demand and dependence on coal-based energy generation capacity, leading to the emission of Green House Gases (GHG). Most of India’s Greenhouse gas emissions are from energy sector having 68.7% contribution in overall greenhouse gas emission. Agriculture, Industrial process land-use change and forestry (LUCF), and waste, contributed 6.0%, 3.8% and 1.9% respectively in overall GHG emission in 2014. [4]. Reducing the GHG emission in India is a major challenge in front of the Government as the Government has to maintain sustainable growth with the contribution in mitigating the effect of climate change. Govt. has pledged to Paris Agreement for the reduction in emission intensity of GDP by 33-35% by 2030 below 2005 level [5]. In the reduction of GHG emission, energy efficiency’s contribution is estimated at approx. 51% [6]. The industrial sector can contribute most in reducing GHG emission and contributes to nationally determined contribution. Industry consumes 40%-45% of total energy consumption and motor-driven system consumes 70% [7] of total Industrial energy. Most of the energy in Industries are consumed to run the motor for various purposes and consumes a major chunk of energy which can be reduced to a significant level by replacing the standard motor with energy efficient motor. 90% of the motor in Indian industries are IE1 or below IE1 standard [8] and required replacement. By installing the energy efficient motor, the industry can save huge energy, cost and reduce CO2 emission. Observing the opportunity for energy saving by energy efficient motor, this paper aims to analyze how energy efficient motor is capable of reducing energy consumption, and how it can contribute to energy conservation. Methodology adopted in this paper is secondary research, that answers to questions like; why Industry need energy efficient motor, how energy efficient motor can save energy and increases efficiency, cost-benefit analysis of installing energy efficient motor, barriers to the installation of energy efficient motor and solution to those barriers in migration from the standard motor to energy efficient motor in India.

New technology trends and policy needs in energy efficient motor systems - A major opportunity for energy and carbon savings

The electric motor market has witnessed a major change in the last decade in several aspects: in structure, with company mergers contributing to a more global market, in content with energy-efficiency policies, and in its economy due to increasing electricity prices, all aspects contributing to push the market towards more energy-efficient electric motors.Additionally, the growing market penetration of Variable Speed Drives (VSD), introducing large energy savings in systems with variable loads, was accompanied by a growing concern over their operating efficiency in full and especially in part-load, as well as in stand-by mode.A Motor Driven Unit (MDU) consists of the core components of a motor system: electric motor, variable speed drive (VSD), mechanical transmission and end-use application, like a pump or fan. Regulating the entire Motor Driven Unit (MDU) would translate into 1400 TWh of cost-effective electricity savings (7% of the World motor systems electricity consumption), with a corresponding reduction in emissions of 469 Mton of CO2eq by 2040. Even larger potential energy savings can be made available by the optimization of the entire motor systems, which translates into 3100 TWh of global electricity savings by 2040. Still to date, Minimum Energy Performance Standards (MEPS) have been mostly targeted at individual components only. Difficulties arise in the standardization of measuring and classifying the entire MDU but the larger energy savings achievable by the motor system is leading to the launch a combined system standard by the International Electrotechnical Committee (IEC) and the International Organization for Standardization (ISO).MEPS and standardization at the component and MDU level must be carefully complemented to achieve the maximum energy savings and carbon emission reductions.This paper carries out novel technical, economic and environmental analyses of introducing new policy measures (standards and MEPS) for both individual components and MDUs.

Design of an energy efficient car by biomimicry of a boxfish

A boxfish has certain aero/hydrodynamic features in its body shape which makes it more efficient in traveling through the water using less energy. Because of the streamline features of the boxfish, it produces less drag for its movement. So, there is a lot of possibility to design a passenger car by implementing the aerodynamic features on the car shape for improving the energy efficiency. This paper investigates the aerodynamic behavior of a boxfish using both experimental and computational methods. A scaled-up model boxfish was manufactured, and passenger car model was also developed by applied certain aerodynamic features on the car shape and a prototype was manufactured. The models were tested in a wind tunnel condition. The results indicate that the drag coefficient of a boxfish is around 0.24 which is significantly lower than current drag coefficient of a passenger car. The car design inspired by boxfish also energy efficient than a commercially manufactured passenger car. Hence, a boxfish shape can be adapted for achieving low drag and energy efficient motor vehicle design.

ANALYSIS OF THE OPERATION OF PUMPING UNIT UNDER A RANGE OF DIFFERENT LOADS

The report analyzes the work of a pumping unit from the hot water installation of the Faculty of Technics and Technologies - Yambol, Bulgaria, under different load conditions. Simulation stands have been adapted that are suitable for analyzing the performance of motors of different types and depending on how they are put into the pump unit. It was found that when the energy inefficient electric motor is directly started, the maximum efficiency is 79,63% and is achieved at 100% of its load. When using a frequency converter, at 100% of its load, the efficiency is 86,83%. The proposed energy-efficient electric motor, with direct start-up, has the highest efficiency of 86,7%. The obtained results can be used in the modernization of the hot water installation of the Faculty of technics and Technologies - Yambol, in the part “pumping units”.

The Design of Control System for Gearless Synchronous Drum-Motor of the Underground Mine Belt Conveyor

Regarding the current tendency of replacing the geared electric drives with gearless drum motor and substitution of the obsolete induction motors with energy-efficient synchronous motors, the authors consider the difficulties of the high-power permanent magnet synchronous motor and present its model with parameters corresponding to the real belt conveyor electric drive parameters. This paper describes the questions of the vector control system simulation for the synchronous gearless drum-motor of an underground belt conveyor. The control of permanent magnet synchronous motor is realized having regard to rotor angle and random traffic flow. The mechanical system of an underground belt conveyor is represented by the multimass system with the viscoelastic bar. As a conclusion, the article presents the results of the direct torque control system simulation in the speed adjustment mode.

Evaluation of manufacturers strategies to obtain high-efficient induction motors

This paper presents a study on how manufacturers are working to comply with the minimum energy performance standards in three-phase squirrel-cage induction-motors. One of the possibilities is to reduce the stator and rotor resistances, and to increase the magnetizing branch resistance. A method to obtain the parameters of the equivalent circuit of the induction motor from the catalog data sheet is shown. A new method to separate the short-circuit reactance in stator and rotor components, based on start-up and breakdown torques, is presented. The variation in rotor parameters as a function of the slip is conveniently accounted for. The proposed methodology is applied to several motors from different manufacturers of significant influence in the European market. The main parameters that affect losses and energy efficiency of motors are compared, establishing an idea on how each of these manufacturers acts to meet energy efficiency requirements.

Magnetic Property of Amorphous Magnetic Thin Ribbon and Its Laminated Bulk Under Tensile and Compressive Stresses

In order to design an energy-efficient motor, it is necessary to clarify the magnetic property of Fe-based amorphous alloys under stress. However, it is difficult to measure the magnetic property of amorphous alloys under stress because a single amorphous ribbon buckles easily under compressive stress. In this paper, we describe our measurement device equipped with a stress loading mechanism of thin ribbon and laminated bulk and compare the measurement results. Our results confirm that when the stress less than -10 MPa is applied, the deviation of maximum magnetic field's strength at 0.5, 1, and 1.3 T increases almost linearly by compressive stress.

Comparative life cycle assessment of microalgae-mediated CO2 capture in open raceway pond and airlift photobioreactor system

A comparative life cycle assessment of CO2 capture potential of microalgae, Scenedesmus dimorphus, during autotrophic cultivation in closed airlift photobioreactor and open raceway pond under Indian conditions has been carried out. The LCA inventory inputs for the both the systems were entirely based on primary experimental data obtained by algal cultivation in 1000-L pilot-scale raceway pond and 5-L airlift photobioreactor, respectively. The primary energy demand, environmental impacts and Net CO2 capture efficiency of both the systems were evaluated. The results indicated that the primary energy demand and GWP of airlift photobioreactor were 3.7-fold higher than raceway pond. The NERCO2 (defined as net emission ratio of CO2 and estimated as ratio of CO2 sequestered/CO2 emitted) of raceway pond was fourfold higher as compared to airlift photobioreactor; however, both the cultivation systems were observed to be net negative in terms of CO2 sequestration. However, the process can become net CO2 positive, with up to fourfold and 7.5-fold enhancement in biomass productivities (wrt base value) for raceway pond and airlift photobioreactor, respectively. Further, LCA predictions indicated that utilization of energy-efficient motors with lower specific energy consumptions for microalgae cultivation would facilitate algal cultivation systems to achieve net CO2-positive sequestration.

Energy‐efficient sensorless load angle control of a BLDC motor using sinusoidal currents

Nowadays, most brushless DC (BLDC) motors use Hall sensors or sensorless algorithms based on back-electromotive force (back-EMF) sensing to detect rotor position information. These methods detect the commutation moments but imply the use of rectangular stator currents which, according to recent literature, limits the energy efficiency. In this study, sinusoidal stator currents are used to increase the motor energy efficiency. As a consequence, standard control based on the feedback of the Hall sensors or based on sensorless techniques detecting the back-EMF zero-crossing cannot be used. Therefore, the authors propose a load angle control algorithm for BLDC motors without using position and speed sensors. The objective is to obtain energy-efficient sensorless control for the BLDC motor based on the measurement of only two current and one voltage signal. The energy saving potential of the proposed method is especially outspoken for fixed speed applications with varying loads, which are typical BLDC applications. Experimental results are presented to validate the proposed method. Energy efficiency measurements over the whole operating range of the BLDC motor are included and show an energy saving potential up to 9.5%.

Technical and Economic Evaluation of Efficiency Improvement after Rewinding in Low-Power Induction Motors: A Brazilian Case

Nowadays the economic analysis of an induction motor’s life cycle is the clearest way to measure the viability of actions to promote energy-efficient technologies to the end user. The cost effectiveness in motors replacement by energy-efficient motors is a well-known practice that leads to energy savings, however this paper presents the cost-effectiveness of low-power induction motors which have their efficiency improved after rewinding. This process improves the investment viability and brings the greatest financial and energetic savings. In this paper, low-power induction motors are rewound and their efficiencies are measured by tests A and B from IEEE standard 112/2017. The rewound motors have better cost-effectiveness than replacement by IE3/Premium and even IE4/Super-Premium units. The rewound motors increase between 3 and 4 percentage points in relation to former efficiency and the payback is less than 2 years, regardless of the efficiency measurement method.

Classification Method to Define Synchronization Capability Limits of Line-Start Permanent-Magnet Motor Using Mesh-Based Magnetic Equivalent Circuit Computation Results

Line start permanent magnet synchronous motors (LS-PMSM) are energy-efficient synchronous motors that can start asynchronously due to a squirrel cage in the rotor. The drawback, however, with this motor type is the chance of failure to synchronize after start-up. To identify the problem, and the stable operation limits, the synchronization at various parameter combinations is investigated. For accurate knowledge of the operation limits to assure synchronization with the utility grid, an accurate classification of parameter combinations is needed. As for this, many simulations have to be executed, a rapid evaluation method is indispensable. To simulate the dynamic behavior in the time domain, several modeling methods exist. In this paper, a discussion is held with respect to different modeling methods. In order to include spatial factors and magnetic nonlinearities, on the one hand, and to restrict the computation time on the other hand, a magnetic equivalent circuit (MEC) modeling method is developed. In order to accelerate numerical convergence, a mesh-based analysis method is applied. The novelty in this paper is the implementation of support vector machine (SVM) to classify the results of simulations at various parameter combinations into successful or unsuccessful synchronization, in order to define the synchronization capability limits. It is explained how these techniques can benefit the simulation time and the evaluation process. The results of the MEC modeling correspond to those obtained with finite element analysis (FEA), despite the reduced computation time. In addition, simulation results obtained with MEC modeling are experimentally validated.

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

Analysis of possibilities for improving energy indicators of induction electric motors for propulsion complexes of autonomous floating vehicles

This study proposes additional possibilities to improve, at minimal efforts, a number of technical-economic indicators of three-phase standard industrial induction motors (IM). We suggest that such engines should be used in the propulsion complexes of modern autonomous floating vehicles (AFV). Such a task is to be solved because of the need to provide the propulsion complex of AFV with energy-efficient and inexpensive electric motors. It is proposed to apply four-pole electric motors, instead of bipolar electric motors, at an elevated rated power frequency (100, 150, 200 Hz). Employing the method of analogies of geometrically similar electric machines, it is substantiated to apply the shortened three-phase four-pole IM instead of bipolar IM. We have conducted a detailed analysis of the basic structural and energy characteristics of the modernized general-purpose IM. It was established that in the modernized four-pole IM of the AFV propulsion complex the weight and size parameters are significantly reduced (by approximately 15 %). This is enabled by a simple structural modernization. Given such a modernization, it is not necessary to manufacture new bearing assemblies, lids; in this case, mass of the utilized active materials decreases (by 10...17 %). The research results make it possible to meet the needs of modern AFV production in energy-efficient (power factor of modernized engines is approximately 0.56) and inexpensive electric motors for a propulsion complex.