IE4 Efficiency Class Research Articles

Sensitivity-Based Design and Optimization of Line Start Synchronous Reluctance Motor

Energy resources are decreasing in the world and the use of electrical machines is increasing. Motor design and development studies are carried out to reduce the losses and increase the efficiency of motors, which are widely used especially in industry. In this study, Line Start Synchronous Reluctance Motor (LS-SynRM) was designed by taking an induction motor, one of the most widely used motors in the industrial field, as a reference. With its rotor cage structure feature, it can be line-start without the need of a driver. The rotor has a lot of design variables due to slots and barriers. Sensitivity analysis was used to determine the effect of design variables on performance criteria such as power factor, efficiency and torque ripple. Subsequently, Multi-Objective Genetic Algorithm (MOGA) optimization was used to find the values of the design variables that bring the motor performance closer to the optimum result. The results of the reference induction motor, initial LS-SynRM, and the optimized LS-SynRM are compared. It has been taken care to preserve the synchronization feature of the LS-SynRM and the related results are given in the analyses. It is shown that the optimized motor is in IE4 efficiency class and operates with low torque ripple.

Design of a 3 kW PMSM with Super Premium Efficiency

Extended use of permanent magnet synchronous motors (PMSMs) has brought the need to design motors that can comply with the latest requirements in terms of efficiency. This paper presents different configurations in the case of a 3 kW PMSM with two pole pairs, focusing on finding the optimal constructive solutions to ensure that it falls within the IE4 efficiency class. Six virtual prototypes were developed and simulated using the Altair FluxMotor software. A detailed comparison between the simulated versions was carried out in terms of overall efficiency, torque ripple, weight and flux density, with the focus on the nominal operating point. The results show that the virtual prototype with a relatively simple rotor design but higher stator slots number had the best results in terms of efficiency and torque ripple at the nominal operating point.

A Study on a Design Considering the Transient State of a Line-Start Permanent Magnet Synchronous Motor Satisfying the Requirements of the IE4 Efficiency Class

In this paper, the transient state analysis of a Line-Start Permanent Magnet Synchronous Motor (LSPMSM) and the optimum design for high efficiency were studied. In the case of an LSPMSM, aluminum bars and permanent magnets are inserted in the rotor. Since it has aluminum bars, it can be directly started on-line without closed-loop control at the time of starting, like an induction motor. Furthermore, once driven, it rotates at a synchronous speed due to the permanent magnets in the steady state. Theoretically, since the rotor bars have no induced current, copper loss does not occur in the rotor bars. Further, because of the inserted permanent magnets, an LSPMSM has a higher power density than an induction motor with the same output power. However, since it is driven directly on-line, the transient state is longer than that of a synchronous motor driven by an inverter. Therefore, it is important to analyze the characteristics of the transient state depending on the rotor shape in the LSPMSM design. In this study, an LSPMSM that has the same outer diameter of a 7.5 kW IE3 efficiency class induction motor currently used for the industry was designed. The optimal design of the motor was designed using Finite-Element Analysis (FEA) and Design of Experiment (D.O.E). In the design process, the velocity ripple was minimized in the transient state, and the steady state was quickly reached. Finally, the efficiency of the motor satisfies the requirements of the IE4 efficiency class, an efficiency standard described in IEC 60034-30, which is an international standard.

Line-Start Synchronous Reluctance Motor: A Reduced Manufacturing Cost Avenue to Achieve IE4 Efficiency Class

Line-Start Synchronous Reluctance Motor: A Reduced Manufacturing Cost Avenue to Achieve IE4 Efficiency Class

Life Cycle Energy Cost Assessment for Pump Units with Various Types of Line-Start Operating Motors Including Cable Losses

The paper presents a comparative analysis of life-cycle energy consumption for three different types of 4 kW line-start motors used in a pump unit with throttling: the most widely used induction motor with IE3 efficiency class, line start permanent magnet synchronous motor with IE4 efficiency class and line start synchronous reluctance motor with IE4 efficiency class. The operating cycle for pump units with constant flow is considered for the above-mentioned types of motors taking into account not only the losses in the pump and motor, but also in the power supply cable. It is shown that the line start synchronous reluctance motor without magnets has the highest efficiency over the entire considered loading range. However, its power factor is lower than that of the synchronous motor with magnets and therefore it has more significant losses in power supply cable. Despite this disadvantage, the line-start reluctance motor is a good alternative to widespread induction motor since it allows saving of approximately 4000 euro more than the latter during the 20 years life cycle. It also provides similar savings in comparison to the permanent magnet synchronous motor, but unlike it, it does not have costly rare-earth materials in the rotor.

Striving for the Highest Efficiency Class With Minimal Impact for Induction Motor Manufacturers

In the recent past, several successful experiences to modify standard efficiency induction motors in premium efficiency class (IE3) machines have been presented, considering simple and low-cost changes in the design and production processes. However, this approach—also known as no-tooling-cost process—seems to have reached its limit without offering appreciable margins above the IE3 efficiency levels. In order to avoid the electromagnetic redesign of entire machine series for an IE4 efficiency class, the authors investigated how to obtain further efficiency gains in the same volumes of IE3 induction motors. The study looked at unconventional modifications in the production process/design procedure that can still be considered to have minimal impact on manufacturers. In particular, stator winding layouts targeted at very low spatial harmonic content, rotor bar skew removal, and rotor slot insulation prior to aluminum cage die casting are investigated as potential low-cost solutions.

Experimental Results of Synchronous Reluctance Motors to Meet the IE4 Efficiency Standards in Variable Speed Applications

Regulation of the efficiency of electric motors worldwide has recently been tightened further because the contribution of electric motors to overall energy consumption cannot be denied. For many years, induction motors have fulfilled tasks in various fields of industry; however, alternative motors have also been gaining attention to realize more cost-effective motors over the long term. It is foreseen that induction motors (IMs) may not be replace-able in single-speed applications, excluding a few special applications; however, applications for which the variation of speed is required offers opportunities for the entry of other motor technologies. Synchronous reluctance motors (SynRMs) are one option that could provide such benefits. This paper provides the experimental results of SynRMs which, under the rated condition, aim to satisfy the IE4 efficiency class. Five Syn- RMs ranging in power through 5.5, 15, 37, 75 to 132 kW have been manufactured and tested for experimental comparison with IMs of equivalent output power.

Increasing the Efficiency to IE4 Class for 5.5 kW Induction Motor Used in Industrial Applications

Energy efficiency means using less energy for the same need. Increasing the efficiency of electric motors can save energy and decrease operating costs. The use of a correct sized electric motor with higher efficiency for the same need will result in energy saving. AC induction motors are dominating the installed electric motor capacity because it offers simple construction, easy maintenance, robustness, and cost-effective solution. They are available in single or multiphase at different power ratings from fractional powers to MWs. In this study; a 5.5 kW, 4-pole, 50 Hz, 3-phase, squirrel cage induction motor with IE2 high-efficiency class is chosen as the reference motor. The motor is re-designed and analyzed to increase its efficiency to IE4 Super-Premium efficiency class. A commercial software based on the finite element method (FEM) is used for numerical modeling. Various techniques are applied to get higher efficiency values in terms of sizing, materials, and manufacturing. IE4 efficiency class is achieved and all designed models are compared to the reference motor in terms of the electrical performance parameters and the cost.

Constructing and mastering the production of energy-efficient asynchronous motors of mass-market series

The basic technical parameters of a series of energy-efficient asynchronous motors are presented. The primary competitive advantages of the 7AVE series are indicated. The main modifications and specialized variants produced based on it are listed. It is noted that modern designs are more efficient (in comparable energy efficiency classes) than the previously produced AIR and 5A series. The definition of the term “service factor” is clarified. The problems of choosing the rational outer diameter of stator cores are discussed. The advantages of CENELEC matching for implementing the highest classes of energy efficiency of low- and medium-power asynchronous motors are noted. The issue of the potential to design asynchronous motors of an ultrahigh energy efficiency class (IE4) is touched upon. The calculated parameters of a motor type with the IE4 efficiency class are presented.