Research

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16 pages, 9278 KiB

Open AccessArticle

Magnetic Screen Effects on Torque Ripple and Efficiency of Dual Air-Gap Surface Permanent Magnet Synchronous Motor

by Kwang-Il Jeong, Reza Heidari, Do-Hyun Kang, Tae-Jun Ahn, Gwan Soo Park, Jin-Woo Ahn and Grace Firsta Lukman

Energies 2023, 16(19), 6969; https://doi.org/10.3390/en16196969 - 06 Oct 2023

Viewed by 749

Abstract

Electric motors with a double air-gap structure offer increased power or torque density compared to their single air-gap counterparts, achievable through double-stator or double-rotor configurations. In a previous study, the authors proposed a double-stator permanent magnet synchronous motor (PMSM) with a magnetic screen [...] Read more.

Electric motors with a double air-gap structure offer increased power or torque density compared to their single air-gap counterparts, achievable through double-stator or double-rotor configurations. In a previous study, the authors proposed a double-stator permanent magnet synchronous motor (PMSM) with a magnetic screen placed in the middle of the rotor to isolate the outer and inner motors. However, the analysis of the magnetic screen was not provided in that study, as the design was arbitrarily chosen. This research focuses on the effects of the magnetic screen size and selects the appropriate dimensions for optimal motor performance. Finite element analysis (FEA) is employed to assess the electromagnetic characteristics of the screen. Subsequently, the motor is manufactured and tested. The results show that the chosen magnetic screen size contributes to significant efficiency improvements. In particular, the motor achieved an efficiency of 95.2% during the qualification test, surpassing the efficiency obtained in the previous study. Full article

(This article belongs to the Special Issue Regulations and Advances in High Performance Electric Motor and Drive)

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14 pages, 1117 KiB

Open AccessArticle

Design of a Direct-Liquid-Cooled Motor and Operation Strategy for the Cooling System

by Ralf Johannes Keuter, Florian Niebuhr, Marius Nozinski, Eike Krüger, Stephan Kabelac and Bernd Ponick

Energies 2023, 16(14), 5319; https://doi.org/10.3390/en16145319 - 12 Jul 2023

Viewed by 1520

Abstract

To make an all-electric aircraft possible, both high power densities and efficiencies are needed. However, particularly high demands are also placed on the thermal management system. Often, the electric motor and cooling system are considered without co-optimization. Particularly in the case of electric [...] Read more.

To make an all-electric aircraft possible, both high power densities and efficiencies are needed. However, particularly high demands are also placed on the thermal management system. Often, the electric motor and cooling system are considered without co-optimization. Particularly in the case of electric motors with conductors directly cooled by a liquid, there is great potential for optimization, since the temperature-dependent Joule losses determine the largest part of the losses. This publication shows the main influencing parameters for the electric motor and cooling system: coolant speed and winding temperature. In addition, the influence of the cooling system control during a flight mission is demonstrated and its potential in mass reduction is quantified. It could be shown that with a low utilized electric motor the maximum winding temperature of 130

°

C is beneficial, the cooling system should work in almost all operation points in its sized operation and the mass of the heat exchanger and pump is negligible compared to the mass of the electric motor and energy storage. Full article

(This article belongs to the Special Issue Regulations and Advances in High Performance Electric Motor and Drive)

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15 pages, 3811 KiB

Open AccessFeature PaperArticle

High-Precision Acquisition Method of Position Signal of Permanent Magnet Direct Drive Servo Motor at Low Speed

by Deli Zhang, Zhaopeng Dong, Feifei Bu, Zijie Gu and Zitao Guo

Energies 2023, 16(11), 4491; https://doi.org/10.3390/en16114491 - 02 Jun 2023

Viewed by 987

Abstract

This paper studies a method for high-precision acquisition of position signals for permanent magnet direct drive servo motors at low speed. First of all, the problem of poor position feedback accuracy and sensor feedback delay in the low-speed operation of the permanent magnet [...] Read more.

This paper studies a method for high-precision acquisition of position signals for permanent magnet direct drive servo motors at low speed. First of all, the problem of poor position feedback accuracy and sensor feedback delay in the low-speed operation of the permanent magnet direct drive servo motor is analyzed. Secondly, through analysis and simulation, it is found that the interpolation method can play a certain role in compensating the rotor position signal. However, when the speed is close to 0, the output signal of the sensor will fluctuate in a short time, which will affect the speed control accuracy. Therefore, this paper uses the observer method to achieve high-precision acquisition of the position signal of the permanent magnet direct drive servo motor at low speed. The observer method adopts the idea of combining the system model and closed-loop control. Additionally, it makes full use of the parameter information of the motor system. The control performance of the motor can be better guaranteed through the design of the observer parameters and the accuracy of the rotor position estimation result has been greatly improved. Finally, an experimental platform for permanent magnet direct drive servo motors is built, and the rotor position signal acquisition method based on the observer method is verified to have good performance through simulation and experiments. Not only the accuracy of the rotor position estimation result is improved, but also the motor control performance is improved, realizing the stable operation of the permanent magnet direct drive servo motor at low speed. Full article

(This article belongs to the Special Issue Regulations and Advances in High Performance Electric Motor and Drive)

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16 pages, 4709 KiB

Open AccessArticle

Application of Active Disturbance Rejection in a Bearingless Machine with Split-Winding

by Rodrigo de Andrade Teixeira, Werbet Luiz Almeida da Silva, Adson Emanuel Santos Amaral, Walter Martins Rodrigues, Andrés Ortiz Salazar and Elmer Rolando Llanos Villarreal

Energies 2023, 16(7), 3100; https://doi.org/10.3390/en16073100 - 29 Mar 2023

Cited by 3 | Viewed by 1170

Abstract

In this paper it is proposed the displacement control of a bearingless induction machine (BIM) with split winding and optimized drive structure using Active Disturbance Rejection Control (ADRC). Considering that the BIM is a multivariable, nonlinear, and time-varying system with coupled variables, advanced [...] Read more.

In this paper it is proposed the displacement control of a bearingless induction machine (BIM) with split winding and optimized drive structure using Active Disturbance Rejection Control (ADRC). Considering that the BIM is a multivariable, nonlinear, and time-varying system with coupled variables, advanced control techniques can be useful in order to make the system operate efficiently and with good dynamic performance. The ADRC considers the total disturbance, composed of unmodeled dynamics, nonlinearities, uncertainties, and load variations, as an extended state and estimates it in real-time through a state observer. This increases the overall robustness of the control system to disturbances of different natures. The application of the ADRC technique on the radial position control of the BIM used in this work showed that a Linear version of ADRC is not able to compensate for radial load disturbances but this drawback can be solved by the use of a nonlinear observer in the ADRC structure. Besides that, both control versions of the ADRC were able to make stable the naturally unstable radial displacement of the machine’s rotor. Full article

(This article belongs to the Special Issue Regulations and Advances in High Performance Electric Motor and Drive)

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19 pages, 10377 KiB

Open AccessArticle

A Study on Performance and Characteristic Analysis According to the Operating Point of IPMSM Drive

by Hyun-Jong Park, Han-Woong Ahn and Sung-Chul Go

Energies 2023, 16(3), 1219; https://doi.org/10.3390/en16031219 - 22 Jan 2023

Cited by 1 | Viewed by 1189

Abstract

This study presents the characteristics and performance of a motor at the operating point based on pulse-width modulation (PWM). PWM is used in modulating the output voltage of a three-phase inverter. The PWM technique has advantages and disadvantages depending on the system size [...] Read more.

This study presents the characteristics and performance of a motor at the operating point based on pulse-width modulation (PWM). PWM is used in modulating the output voltage of a three-phase inverter. The PWM technique has advantages and disadvantages depending on the system size and operating range. For example, some discontinuous pulse-width modulation (DPWM) techniques are advantageous in low-cost systems because they can reduce the number of switches. Some PWM techniques are complicated for software construction and require a lot of computation. In this paper, PWM techniques were constructed by using the offset voltage injection method. Therefore, the construction of the PWM technique is simplified by the method. In an experimental setup, an interior permanent-magnet synchronous motor (IPMSM) and a three-phase inverter were implemented to test motor control performance depending on the PWM technique. In addition, the current control characteristics and inverter efficiency were analyzed and compared depending on the speed and load of the motor. According to the results of this paper, it is possible to compare the motor and inverter control characteristics using various types of PWM rapidly. Additionally, it will help to select an appropriate PWM technique for a specific system. Full article

(This article belongs to the Special Issue Regulations and Advances in High Performance Electric Motor and Drive)

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14 pages, 6194 KiB

Open AccessArticle

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

by Hyun-Jong Park, Hyeon-Bin Hong and Ki-Doek Lee

Energies 2022, 15(24), 9644; https://doi.org/10.3390/en15249644 - 19 Dec 2022

Cited by 3 | Viewed by 1242

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Regulations and Advances in High Performance Electric Motor and Drive)

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15 pages, 6120 KiB

Open AccessArticle

Investigation of Electromagnetic Losses Considering Current Harmonics in High-Speed Permanent Magnet Synchronous Motor

by Ju-Hyeong Lee, Soyoung Sung, Han-Wook Cho, Jang-Young Choi and Kyung-Hun Shin

Energies 2022, 15(23), 9213; https://doi.org/10.3390/en15239213 - 05 Dec 2022

Cited by 3 | Viewed by 1671

Abstract

This paper presents a characteristic analysis and experimental verification for predicting the electromagnetic losses in high-speed permanent magnet synchronous motors. To predict the operating characteristics (such as speed and input current), dynamic modeling is conducted that combines models for the space vector pulse [...] Read more.

This paper presents a characteristic analysis and experimental verification for predicting the electromagnetic losses in high-speed permanent magnet synchronous motors. To predict the operating characteristics (such as speed and input current), dynamic modeling is conducted that combines models for the space vector pulse width modulation (SVPWM) inverter and high-speed permanent magnet synchronous motor (HPMSM). By applying the predicted harmonic currents to the electromagnetic analysis, DC and AC copper losses of the stator winding, and eddy current loss of the rotor sleeve and rotor permanent magnet, are comprehensively analyzed using the finite element (FE) method. In particular, by analyzing the magnetic field behavior of magnetic flux density according to harmonics, a core loss analysis technique was presented. The validity of the hybrid analysis, which combines the stator copper loss and rotor eddy current loss derived from the FE analysis and the proposed core loss analysis, was verified through comparison with the experimental results under various operating conditions. Compared with the experimental results, the error of total losses using the hybrid analysis with a sinusoidal current was about 47.39%, and total losses using the hybrid analysis with a harmonic current was significantly improved to within 3.7%. Full article

(This article belongs to the Special Issue Regulations and Advances in High Performance Electric Motor and Drive)

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14 pages, 13789 KiB

Open AccessArticle

Characteristics Evaluation of a Segmental Rotor Type Switched Reluctance Motor with Concentrated Winding for Torque Density and Efficiency Improvement

by Zhenyao Xu, Tao Li, Fengge Zhang, Huijun Wang, Dong-Hee Lee and Jin-Woo Ahn

Energies 2022, 15(23), 8915; https://doi.org/10.3390/en15238915 - 25 Nov 2022

Cited by 2 | Viewed by 1442

Abstract

With the rapid development of power electronic techniques and the increasing cost of permanent magnets (PMs) materials, switched reluctance motors (SRMs) have recently gained more attention. However, traditional SRMs have a relatively low torque density. For the sake of increasing the motor torque [...] Read more.

With the rapid development of power electronic techniques and the increasing cost of permanent magnets (PMs) materials, switched reluctance motors (SRMs) have recently gained more attention. However, traditional SRMs have a relatively low torque density. For the sake of increasing the motor torque density, this paper proposes a novel segmental rotor type SRM. The proposed motor adopts hybrid stator poles and concentrated windings in the stator side and a segmental rotor structure in the rotor side, which is completely different from the structures of the traditional SRM. The special structure of the motor shortens the magnetic flux paths of the motor, separates the parts of the magnetic flux paths from one another, and eradicates the magnetic flux reversal in the motor stator in order to improve the electric utilization and output torque density of the motor. Meanwhile, the requirement of the magneto-motive force and the core loss of the motor is also decreased, thereby improving the efficiency of the motor. For the purpose of proving the proposed structure, the characteristics of the motor are analyzed using the finite element method and are compared to those of the traditional 12/8 SRM, which is designed for the same application. Moreover, the prototypes of the traditional 12/8 and proposed SRMs are manufactured, and experiments based on the prototypes are performed. Finally, the effectiveness of the structure of the proposed motor is further proven by the experimental results. Full article

(This article belongs to the Special Issue Regulations and Advances in High Performance Electric Motor and Drive)

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10 pages, 2978 KiB

Open AccessArticle

Optimal Design of Permanent Magnet Synchronous Machine Based on Random Walk Method and Semi 3D Magnetic Equivalent Circuit Considering Overhang Effect

by Su-min Kim, Woo-Sung Jung, Woo-Hyeon Kim, Tae-Kyoung Bang, Dae-Hyun Lee, Yong-Joo Kim and Jang-Young Choi

Energies 2022, 15(21), 7852; https://doi.org/10.3390/en15217852 - 23 Oct 2022

Cited by 3 | Viewed by 1786

Abstract

Permanent magnet synchronous machines (PMSMs) with an overhang structure can increase power density by compensating for the increased magnetic energy of permanent magnets. To analyze the overhang structure, a three-dimensional (3D) analysis of PMSMs is essential. However, 3D analysis takes a long time [...] Read more.

Permanent magnet synchronous machines (PMSMs) with an overhang structure can increase power density by compensating for the increased magnetic energy of permanent magnets. To analyze the overhang structure, a three-dimensional (3D) analysis of PMSMs is essential. However, 3D analysis takes a long time and the modeling process is complicated in the initial design stage. To overcome these problems, a magnetic equivalent circuit technique is applied to the 2D model. In this paper, an optimal design method for PMSMs with an overhang structure is proposed based on the semi 3D magnetic equivalent circuit (MEC) and random walk method. By using semi 3D MEC, it is possible to quickly analyze PMSM and obtain accurate electromagnetic analysis results considering the overhang effect. Moreover, the volume and weight of PMSM can be minimized by optimizing the rotor’s four design parameters using a random walk algorithm. To obtain high efficiency, the objective function is selected so that copper loss is minimized under the same constraints. The validity of the proposed design technique is verified by comparing the analysis results of semi 3D MEC and 3D finite element method for the derived optimal model. Full article

(This article belongs to the Special Issue Regulations and Advances in High Performance Electric Motor and Drive)

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11 pages, 3211 KiB

Open AccessArticle

Multi-Objective Optimal Design of SPMSM for Electric Compressor Using Analytical Method and NSGA-II Algorithm

by Seong-Tae Jo, Woo-Hyeon Kim, Young-Keun Lee, Yong-Joo Kim and Jang-Young Choi

Energies 2022, 15(20), 7510; https://doi.org/10.3390/en15207510 - 12 Oct 2022

Cited by 2 | Viewed by 1194

Abstract

In contrast to internal combustion engine vehicles, electric vehicles (EVs) obtain the power required for the compressor of air conditioning system from an electric source. Therefore, an optimal design for electric motor, the main component of an electric compressor, is essential for improving [...] Read more.

In contrast to internal combustion engine vehicles, electric vehicles (EVs) obtain the power required for the compressor of air conditioning system from an electric source. Therefore, an optimal design for electric motor, the main component of an electric compressor, is essential for improving EV mileage. A multi-objective optimal design is required because the characteristics of the motor are in a trade-off relationship with each other. When the finite element method (FEM) is used, multi-objective optimal designs for the motor take a significant amount of time because of the diversity analyses required for the optimal-model search. To solve this problem, in this study, a multi-objective optimal design method of an SPMSM for an EVs air conditioner system compressor was proposed and applied using the NSGA-II and an analytical method. The validity of the proposed method was confirmed by comparing the characteristics of the optimal design model with those of the initially designed model. Full article

(This article belongs to the Special Issue Regulations and Advances in High Performance Electric Motor and Drive)

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14 pages, 7850 KiB

Open AccessArticle

Novel Multi-Physics Computational Simulation of a 10 kW Permanent Magnet Motor for Podded Propulsion

by Jang-Hyun Park, Tae-Woo Lee, Yeon-Ho Jeong and Do-Kwan Hong

Energies 2022, 15(18), 6607; https://doi.org/10.3390/en15186607 - 09 Sep 2022

Cited by 3 | Viewed by 1345

Abstract

This paper presents a 10 kW, 12-slot 10-pole surface-mounted permanent magnet synchronous motor (SPMSM) design with fractional-slot concentrated winding for a podded propulsion system. Its load is a propeller that is proportional to the square of the rotational speed and the fifth power [...] Read more.

This paper presents a 10 kW, 12-slot 10-pole surface-mounted permanent magnet synchronous motor (SPMSM) design with fractional-slot concentrated winding for a podded propulsion system. Its load is a propeller that is proportional to the square of the rotational speed and the fifth power of the propeller diameter. Taking this into account, three SPMSMs with rated rotational speeds of 600, 1200, and 1800 rpm with the same rated output power of 10 kW were analyzed. These were designed under the same conditions (i.e., torque per rotor volume, air-gap length, current density, power factor, fill-factor, and supply voltage). Based on the SPMSMs designed by electromagnetic analysis, the housing of a podded propulsor for each SPMSM was modeled for mechanical analysis, including such parameters as forced vibration, radiated noise, and modal acoustics analysis in air and water. From the modal acoustics analysis, it is confirmed that the natural frequencies of a structure in water are lower than those in air because of the added mass effect of water. Full article

(This article belongs to the Special Issue Regulations and Advances in High Performance Electric Motor and Drive)

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Review

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27 pages, 8126 KiB

Open AccessReview

A Review on Segmented Switched Reluctance Motors

by Zhenyao Xu, Tao Li, Fengge Zhang, Yue Zhang, Dong-Hee Lee and Jin-Woo Ahn

Energies 2022, 15(23), 9212; https://doi.org/10.3390/en15239212 - 05 Dec 2022

Cited by 8 | Viewed by 2650

Abstract

The switched reluctance motor (SRM) benefits from its magnet-free nature, robust construction, low cost, flexible controls, and the ability to operate in harsh environments such as high temperatures and high pressure. It has received increasing attention for all-electric or multi-electric aircraft systems and [...] Read more.

The switched reluctance motor (SRM) benefits from its magnet-free nature, robust construction, low cost, flexible controls, and the ability to operate in harsh environments such as high temperatures and high pressure. It has received increasing attention for all-electric or multi-electric aircraft systems and electric vehicles (EVs) as compared with permanent magnet synchronous motors (PMSM) and other AC motors in some required high reliability and fault tolerance applications. However, the SRM is prone to considerable wind resistance due to the convex pole structure of the rotor during high-speed rotation, high torque ripple, and also vibration noise. Thus, it is currently a trending topic to develop special SRMs, tailored with high reliability and fault tolerance. Recent research demonstrates several promising feasible solutions to reduce torque ripples and enhance torque density and power factors, including changing topology of SRM, using advanced control methods, as well as different winding configurations. Among these options, the segmented switched reluctance motor (SSRM), as a deformation of the conventional topology, is shown to be capable of effectively optimizing the torque performance. Motivated by this advance, this paper aims to present a comprehensive literature review on the SSRM, first illustrating the development of the topology of the SRM, then providing a description as well as a classification according to the topology of the SSRM. In particular, we focus on the evolution of various kinds of segmental topology and improvement measures. Then, we discuss the performance, advantages, and disadvantages of various types of structures in terms of their electromagnetic aspects and their applications. Eventually, several promising future trends and application prospects of the SSRM are prospected, with the aim of shedding light on further research. In sum, the key contribution of this paper is to provide a valuable basis for detailed analyses of the structure and electromagnetic design of the SSRM that are expected to benefit future research. Full article

(This article belongs to the Special Issue Regulations and Advances in High Performance Electric Motor and Drive)

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