我国中小型电机制造业市场前景分析

我国将会成为世界电动机,特别是中小电动机的生产制造基地;我国出口电机竞争能力亟待加强,产品开发要与国际接轨,以打入国际市场为主攻方向,从产品质量、外观、性能、安装尺寸、可靠性等方面增强在国际市场的竞争能力;国家优惠政策给电机行业带来了积极的影响     

A novel high power density permanent magnet variable-speed motor

A novel polyphase, multipole, permanent magnet (PM) motor which possesses high power density, high efficiency and excellent controllability, yet can be produced by conventional fabrication techniques, is proposed. The basic operating principles, design features, performance analysis and control system are described. The experimental results for a 5 kW, 1500 RPM prototype PM motor and its comparison with other types of motors such as switched reluctance motors and induction motors are given. This motor also has superior dynamic performance     

Energy efficiency in pumps

In this paper, “energy efficiency” studies, done in a big industrial facility’s pumps, are reported. For this purpose; the flow rate, pressure and temperature have been measured for each pump in different operating conditions and at maximum load. In addition, the electrical power drawn by the electric motor has been measured. The efficiencies of the existing pumps and electric motor have been calculated by using the measured data.

Potential energy saving opportunities have been studied by taking into account the results of the calculations for each pump and electric motor. As a conclusion, improvements should be made each system. The required investment costs for these improvements have been determined, and simple payback periods have been calculated.

The main energy saving opportunities result from: replacements of the existing low efficiency pumps, maintenance of the pumps whose efficiencies start to decline at certain range, replacements of high power electric motors with electric motors that have suitable power, usage of high efficiency electric motors and elimination of cavitation problems.     

电机产品强制性能效标准研究

电机用电是工业用电的60％左右,电机强制性能效标准对推动高效电机的应用起重要作用。在分析我国电机能效现状的基础上,指出我国电机能效和发达国家电机能效的差距。针对电机能效强制性标准以及测试标准的发展历程,主要介绍了北美和欧盟的强制性标准的关键内容。最后提出了提高电机能效的相关建议。     

Energy conservation by using energy efficient electric motors

This paper deals with energy conservation by installing energy-efficient (EE) motors instead of standard efficiency motors. This transition become a necessity as a direct result of limitation in energy sources and escalating energy prices. As electric motors use about three quarters of the total electric energy in Bahrain, attempts to conserve the energy consumed by electric motors recently received intensive research efforts. Therefore, the energy efficiencies of energy efficient motors are compared with those of standard efficiency motors ranging from 5 to 300 HP. To provide more clarification in this regard, full design details of 200 HP standard-efficiency and energy-efficient motors are compared. Pay back periods when replacing standard-efficiency motors with energy-efficient motors, with reference to Bahrain's market, have been discussed. Finally the energy-conservation capability of EE motors in the petrochemical industry has been discussed.     

Exploitation of vehicle's kinetic energy in power management of tow -wheel drive electric vehicles based on ANFIS DTC-SVM comparative study

The concept of the hybrid power system in electric vehicles means that there are many sources in this electric vehicle. The electric vehicle of two-wheel drives motors doesn't exploit the two front wheel; this kind of electric vehicle prompted us to propose using the front wheels in electric vehicle energy management, which creates another energy source. The hybrid vehicle can associate more than one source to each other to secure a long time working. The two rear wheels are generally controlled by classical controllers as the DTC-SVM controller that is one of many methods to control a motor's speed. It Based on three classical controllers. We want to replace the PI speed controller with an intelligent controller and show the possibility of integrating it in this kind of control. In this paper, we exploit the electric vehicle's Kinetic energy in energy management by combining the permanent magnet synchronous generator in the vehicle's front wheels, and integrating the ANFIS controller with back motors. The generator's power represents about 19% of the total electric vehicle power. The ANFIS management strategy gave the best résults 96.6 as efficiency and the smallest consumption of Air/fuel compared with the others methods about 55.75–199 (Ipm).     

Development and performance characterization of an electric ground vehicle with independently actuated in-wheel motors

This paper presents the development and experimental characterizations of a prototyping pure electric ground vehicle, which is equipped with four independently actuated in-wheel motors (FIAIWM) and is powered by a 72 V 200 Ah LiFeYPO₄ battery pack. Such an electric ground vehicle (EGV) employs four in-wheel (or hub) motors to independently drive/brake the four wheels and is one of the promising vehicle architectures primarily due to its actuation flexibility, energy efficiency, and performance potentials. Experimental data obtained from the EGV chassis dynamometer tests were employed to generate the in-wheel motor torque response and power efficiency maps in both driving and regenerative braking modes. A torque distribution method is proposed to show the potentials of optimizing the FIAIWM EGV operational energy efficiency by utilizing the actuation flexibility and the characterized in-wheel motor efficiency and torque response.     

Asynchronous Performance Prediction of AC Permanent Magnet Motor

many permanent magnet synchronous motors are run up from standstill by a sudden connection with an ac supply. The cage windings in rotor slots produce induction motor torque to run up the rotor, but two torque dips are produced in the torque-slip curve of the permanent magnet motor; one is caused by the rotating permanent magnet, and the other by the magnetic and the electric asymmetry between the direct and quadrature axes. Therefore, the prediction of the asynchronous performance is very important, as motors cannot be run up, unless the minimum values of the torque dips exceed the load torques at the slips. In this paper, ``harmonic permeance coefficient' is newly introduced, which is used to combine the finite element field solution with the calculation of air gap inductance, and equations for the calculation of asynchronous performance of permanent magnet motors are also expressed. The calculated value by these equations agreed well with the experimental results.     

Method for in-field evaluation of the stator winding connection of three-phase induction motors to maximize efficiency and power factor

The performance of the oversized three-phase induction motors can be improved, both in terms of efficiency and power factor, with the proper change of the stator winding connection, which can be delta or star, as a function of their load. A practical method is proposed to quickly and easily evaluate which stator winding connection is more appropriate for the actual motor load profile, in order to increase the motor efficiency and power factor. This new method is suitable for in-field evaluation, because it requires only the use of inexpensive equipment and has enough accuracy to allow a proper decision to be made. The automatic change of the stator winding connection, as a function of the motor line current, is also analyzed. When properly applied, these methods can lead to the improvement of the efficiency and power factor of permanently oversized motors, motors with a load variation between low load and near full load during their duty cycle, and/or motors driving high-inertia, low duty cycle loads. The proposed methods are particularly suitable to industrial plants where typically many electric motor systems are oversized and/or can have a wide load variation. In these conditions, the active and reactive electrical energy bill can be significantly reduced.     

A comparative review on power conversion topologies and energy storage system for electric vehicles

Fossil fuel depletion and its adverse impact on global warming is a major driving force for a recent upsurge in the development of hybrid electric vehicles technologies. This paper is a conglomeration of the recent literature in the usages of an energy storage system and power conversion topologies in electric vehicles (EVs). An EV requires sources that have high power and energy density to decrease the charging time. Commonly used energy storage devices in EVs are fuel cells, batteries, ultracapacitors, flywheel, and photovoltaic arrays. The power output from energy storage sources is conditioned to match load characteristics with the source for maximum power delivery. A DC-DC converter topology performs this task by way of transforming voltage under the condition of power invariance. In addition, power electronics is also required to power DC/AC motors efficiently with precise control as these motors provide tractive efforts and acts as prime movers. This paper therefore brings out a critical review of the literature on EV's power conversion topologies and energy storage systems with challenges, opportunities and future directions by systematic classification of EVs and energy storage.     

工业电机能效检测技术研究

工业电机电耗占全球电力消耗的30％-40％,其中三相感应电机又占工业电机的大部分;工业电机的效率检测技术是能效法规和标准的技术支撑。文中分析了主要国家和地区的电机能效评价和检测技术,探讨了两种标准（IEEE112B和IEC60034—2）的不同之处,认为电机能效等级分类和检测技术将逐步统一。     

Energy-efficiency standards for electric motors in Brazilian industry

The first regulation of the “Energy Efficient Act” for electric motors, launched in 2002, established two sets of minimum efficiency performance standards (MEPS), for ‘standard’ (mandatory) and ‘high efficiency’ (voluntary) motors. An updated regulation, from the end of 2005 (Edict 553/2005), established the previous high-efficiency MEPS as mandatory for all motors in the Brazilian market. This paper analyses the consequences of this new regulation, which is foreseen to take effect in 2010. These new Brazilian MEPS are compatible with those implemented in other countries. The cost–benefit analysis, considered for different scenarios for industrial consumers, showed that motor substitution (from standard to high efficiency) is generally advantageous. A sample of nine thousand industrial motors has been used, with measured operation in actual conditions, to analyze the investment cost–benefit in three different scenarios. This analysis also demonstrated the benefit of motor substitution, with an average MWh cost from 20 to 35 US$, and with only a few substitutions presenting an unfavorable cost–benefit relationship to the user. We assess that Edict 553 avoided construction of 350 MW of hydroelectric capacity. Nevertheless, since the cost of conserved energy for this energy-saving measure is generally below the marginal cost of expansion of the Brazilian electric system, we propose mechanisms to share investment costs among the society as a whole, including demand-side bidding.     

A review on electrical motors energy use and energy savings

The industrial sector is the largest users of energy around the world. Industrial motor uses a major fraction of total industrial energy uses. This paper describes a comprehensive literature review about electric motor energy analysis. This paper compiles latest literatures in terms of thesis (MS and PhD), journal articles, conference proceedings, web materials, reports, books, handbooks on electrical motor energy use, losses, efficiency, energy savings strategies. Different types of losses that occur in a motor have been identified and ways to overcome these losses explained. An energy audit that helps to identify motor energy wastages have been discussed extensively. As motors are the major energy users, different energy savings strategies such as use of high-efficient motor, variable speed drive (VSD), and capacitor bank to improve the power factor to reduce their energy uses have reviewed. Different policy measures (i.e. regulatory, voluntary and incentives based) to save motor energy use have been reviewed and presented in this paper. In this review, computer tools that can be used to analyze electric motors energy used has been discussed. Cost parameters to carry out economic analysis have been shown as well. Moreover, payback period for different energy savings strategies have been identified.     

Modeling and analysis of variable speed single phase induction motors with iron loss

Despite their usual low power ratings of single phase induction motors, they consume a considerable part of total motors energy consumption due to their large and ever-increasing quantity. The recent rising of oil prices and environmental crises has fortified the idea of energy saving practices in all applications; particularly in single phase induction motors due to their typical low efficiency. An essential requirement for this practice is the modeling and analysis of machine electrical losses under variable frequency operation. In this paper an improved steady state model of single phase induction motors is derived to investigate major motor characteristics like torque–speed, input power, output power, etc. A special emphasis is placed on accurately representing core losses at variable frequency. The winding currents phase difference is reintroduced as a fundamental motor variable to determine motor performances including losses and efficiency. An advanced computerized motor test setup is designed and built for on-line measurement of motor characteristics at different supply and operating conditions. The extensive experimental results, in good agreement with the simulation results based on the mentioned analysis, confirm the validity of the proposed model.     

Introduction to motors and controllers of flywheel energy storage systems

简述了飞轮储能系统的基本组成,介绍了飞轮储能系统常用的永磁无刷直流电机、永磁同步电机、感应电机和开关磁阻电机的工作原理和特点,讨论了四种电机的控制策略,分析了各种控制策略的优缺点及其应用。     

Energy and emission analysis for industrial motors in Malaysia

The industrial sector is the largest user of energy in Malaysia. Industrial motors account for a major segment of total industrial energy use. Since motors are the principle energy users, different energy savings strategies have been applied to reduce their energy consumption and associated emissions released into the atmosphere. These strategies include using highly efficient motors, variable speed drive (VSD), and capacitor banks to improve the power factor. It has been estimated that there can be a total energy savings of 1765, 2703 and 3605 MWh by utilizing energy-efficient motors for 50%, 75% and 100% loads, respectively. It was also found that for different motor loads, an estimated US$115,936 US$173,019 and US$230,693 can be saved in anticipated energy costs. Similarly, it is hypothesized that a significant amount of energy can be saved using VSD and capacitor banks to reduce speed and improve the power factor, thus cutting energy costs. Moreover, a substantial reduction in the amount of emissions can be effected together with the associated energy savings for different energy savings strategies. In addition, the payback period for different energy savings strategies has been found to be reasonable in some cases.     

Novel Multiflux Level, Three-Phase, Squirrel-Cage Induction Motor for Efficiency and Power Factor Maximization

In the European Union, the average load factor of electric motors in both industrial and tertiary sectors is estimated to be less than 60%. However, in some industrial sectors, the average load factor for some motor power ranges can be as low as 25%. Most oversized three-phase induction motors operate with low efficiency and power factor, which is, by far, the most important cause for poor power factor in industrial installations. In the low-load operating periods, motor performance can be improved both in terms of efficiency and power factor if the magnetizing flux is properly regulated. In this paper, a multiflux level, three-phase, squirrel-cage induction motor is proposed, in which the efficiency and power factor can be both maximized as a function of load. This novel motor can be a surplus value in industry due to its flexibility, particularly, for variable load applications in which significant energy savings can be obtained, and can also be used as new or rewound general purpose spare motor (with several levels of voltage, magnetizing flux and/or power). The proposed motor has a stator winding with two sets of turns, sharing the same positions in the stator slots (which can be connected either in series or in parallel). Among all the possible stator winding connections, six modes were selected and analyzed (two of which are new). The basic principles for proper connection mode change are discussed. An electronic device and a contactor concept for automatic connection mode change are proposed. As far as the authors know, this concept is described and analyzed for the first time.     

The available matching of solar arrays to DC motors having both constant and series-excited field components

This paper presents a procedure for increasing the daily output mechanical energy supplied by DC motors directly connected to solar cell arrays (SCA). The technique is based on the use of DC motors with two components of magnetic field: a constant component that can be provided by a permanent magnet (or a separately excited winding) and a second one produced by a series field winding. It will be shown that through properly selecting the parameters of the motor's magnetic circuit, (i.e., the value of the constant field and the mutual inductance as well as their relative directions), an improved matching between the PV-array and the dc motor can be achieved. Based on assessing and minimizing an expression used to quantify the power mismatch between the SCA and the dc motor, the optimal parameters will be identified. A comparison will then be made between this suggested motor design and tooth the separately excited and series motors.     

Starting characteristics of direct current motors powered by solarcells

The authors deal with the calculation of the starting to rated current ratio and starting to rated torque ratio of the permanent magnet, separately, series and shunt excited motors when powered by solar cells for the two cases where the system includes a maximum-power-point-tracker (MPPT), and without an MPPT. Comparing these two cases, one gets a torque magnification of about three for the permanent magnet motor and about seven for other motor types at rated design insolation. The calculation of the torques may assist the photovoltaic system designer to determine the advantage of including an MPPT in the system as far as the starting characteristics of the DC motors are concerned     

A maximum efficiency-photovoltaic-induction motor pump system

It is not economically viable to connect remote areas to the national electric grid, so pumping systems based on photovoltaic energy sources are suitable for these areas. The induction motor is more rugged, reliable, and maintenance free than d.c. motors. In this paper, a pumping system based on an induction motor driven by a voltage source inverter is investigated. Two control strategies are considered. First, the system is controlled to operate on the maximum power line of the PV array, with variable water discharge Q. Second, the induction machine is controlled to operate at maximum efficiency. The operating characteristic of the array is thus controlled to match the voltage and current required by the motor. Comparison is carried out between the two operating schemes.