United States

Permanent magnet (PM) motors have been widely applicable for electric vehicles due to their excellent power density and efficiency. Yet, due to the relatively constant
airgap magnetic field, the motor always suffers from a limited speed range. So, the achievement of a wide speed range is one of the hot research orientations for PM motors. In recent years,
a type of leakage-flux-controllable (LFC) motor has attracted some interest and attention of researchers, where the magnetic bridge and flux barrier are purposely designed in PM rotor for
forming the controllable leakage flux[1]. Based on this, the LFC-PM motor possesses the potential advantages of speed regulation[2]. It is noted that to realize the condition of no leakage
flux in motor drive process, a relatively strong armature field is usually required to be applied at this time, and, correspondingly, the magnetic saturation comes with that. It means that the
torque capability of LFC PM motor is worthy of attention and full of challenge, especially on the drive requirements of low-speed large torque.
In this study, a V-typed leakage-flux-controllable PM (VFLC-PM) motor with multiple functional magnetic flux barrier units is proposed, which can provide relatively high output torque
and a wide speed range. The motor topology and magnetic barrier structure analysis are shown in Fig. 1. The magnetic field distributions under different operating conditions are shown in
Fig. 2. At no load, the flux leakage barrier guides parts of PM flux into the flux leakage path and reduces the air gap effective flux. As the armature current increases, the flux focusing
barrier guides the PM flux to pass through the air gap rather than flux leakage path, and the main flux is enhanced. And then, a response surface method is adopted to optimize the key
parameters related to the magnetic flux barrier units in Fig. 3. After optimization, the torque performances of the motor are significantly improved both at different operating conditions as
shown in Fig. 4. Finally, the torque characteristics of the motor are verified through experiments in Fig. 5. The experimental results are in good agreement with the simulation results,
which verifies the effectiveness of the motor design.&lt;br&gt;

**References:**&lt;br&gt;

[1] T. Kato, T. Matsuura and K. Sasaki, Proc. IEEE Energy Convers. Congr. Expo., 2017, pp. 5803–5810.&lt;br&gt;

[2] X. Zhou, X. Zhu and W. Wu, IEEE Trans. Ind. Electron., vol. 68, no. 8, pp. 6516–6526, Aug. 2021.&lt;br&gt;

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MMM 2022

Design and Analysis of a V Shaped Leakage

Permanent magnet (PM) motors have been widely applicable for electric vehicles due to their excellent power density and efficiency. Yet, due to the relatively constant
airgap magnetic field, the motor always suffers from a limited speed range. So, the achievement of a wide speed range is one of the hot research orientations for PM motors. In recent years,
a type of leakage-flux-controllable (LFC) motor has attracted some interest and attention of researchers, where the magnetic bridge and flux barrier are purposely designed in PM rotor for
forming the controllable leakage flux[1]. Based on this, the LFC-PM motor possesses the potential advantages of speed regulation[2]. It is noted that to realize the condition of no leakage
flux in motor drive process, a relatively strong armature field is usually required to be applied at this time, and, correspondingly, the magnetic saturation comes with that. It means that the
torque capability of LFC PM motor is worthy of attention and full of challenge, especially on the drive requirements of low-speed large torque.
In this study, a V-typed leakage-flux-controllable PM (VFLC-PM) motor with multiple functional magnetic flux barrier units is proposed, which can provide relatively high output torque
and a wide speed range. The motor topology and magnetic barrier structure analysis are shown in Fig. 1. The magnetic field distributions under different operating conditions are shown in
Fig. 2. At no load, the flux leakage barrier guides parts of PM flux into the flux leakage path and reduces the air gap effective flux. As the armature current increases, the flux focusing
barrier guides the PM flux to pass through the air gap rather than flux leakage path, and the main flux is enhanced. And then, a response surface method is adopted to optimize the key
parameters related to the magnetic flux barrier units in Fig. 3. After optimization, the torque performances of the motor are significantly improved both at different operating conditions as
shown in Fig. 4. Finally, the torque characteristics of the motor are verified through experiments in Fig. 5. The experimental results are in good agreement with the simulation results,
which verifies the effectiveness of the motor design. 

**References:** 

[1] T. Kato, T. Matsuura and K. Sasaki, Proc. IEEE Energy Convers. Congr. Expo., 2017, pp. 5803–5810. 

[2] X. Zhou, X. Zhu and W. Wu, IEEE Trans. Ind. Electron., vol. 68, no. 8, pp. 6516–6526, Aug. 2021. 

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poster

#### Welcome to the 67th Annual Conference on Magnetism and Magnetic Materials, MMM 2022!

The Conference was held from October 31 to November 4 and offers both in-person and on-demand content.

MMM 2022 is sponsored jointly by AIP Publishing and the IEEE Magnetics Society. Members of the international scientific and engineering communities interested in recent developments in fundamental and applied magnetism are invited to attend and contribute to the technical sessions. The technical program will include invited and contributed papers in oral and poster sessions, invited symposia, a tutorial, and several special sessions. This Conference provides an outstanding opportunity for worldwide participants to meet their colleagues and collaborators and discuss developments in all areas of magnetism research.

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Please register for the MMM 2022 conference to join the event.

This Conference provides an outstanding opportunity for worldwide participants to meet their colleagues and collaborators and discuss developments in all areas of magnetism research.

In recent years, variable leakage flux permanent magnet (VLF-PM) motors, which can realize different operation conditions, have attracted increasing attention [1]. In this
kind of motors, by the purposeful design of flux barriers and PMs, design requirements of different operation conditions can be satisfied [2]. It is noted that, under different working
conditions, different flux density distribution often leads to significant changes in radial electromagnetic force distribution and characteristics of vibration noise [3]. Thus, it is necessary to
design and analyze the characteristic of vibration noise of VLF-PM motor under multiple working conditions. In this paper, the characteristics of electromagnetic vibration of VLF-PM
motor under different working conditions are researched. And, an low vibration design method is proposed for VLF-PM motors, considering multiple working conditions.
Fig. 1 shows the proposed VLF-PM motor and operation principle under different operation conditions. Fig. 2 presents the characteristics of electromagnetic vibration of the VLF-PM
motor in different working regions. According to the operation principle, two typical working points are selected for analysis. The sensitivity of design parameters to the desired
optimization objective are depicted in Fig. 3, and the selected sensitive parameters are marked. The characteristics of sensitive design parameters are illustrated in Fig. 4. The basic
electromagnetic performances under two working points are shown in Fig. 5. It can be seen that under the two working conditions, the output torque of the two motors is almost the same,
and the torque ripple of the optimal motor is obviously reduced. Fig. 6 shows the vibration characteristics of VLF-PM motor. Due to the lower amplitudes of low-order radial force density,
especially, 4th, the vibration and noise characteristics of the optimal VLF-PM motor is preferred under the two working points, which verifies the effectiveness of the low vibration design
of the VLF-PM motor proposed in this paper.
More detailed analysis and experimental verification will be presented in the full paper. 


**References:** 

[1] H. Hu, Z. Xiang and X. Zhu, IEEE Transactions on Magnetics, vol. 58, no. 2, pp. 1-6, Feb. 2022, Art no. 8102606. 
[2] X. Zhou, X. Zhu and W. Wu, IEEE Transactions on Industrial Electronics, vol. 68, no. 8, pp. 6516-6526, Aug. 2021. 
[3] M. S. Islam, R. Islam and T. Sebastian, IEEE Transactions on Industry Applications, vol. 50, no. 5, pp. 3214-3222, Sept.-Oct. 2014. 

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Low Vibration Design of Variable Leakage Flux Permanent Magnet Motor Considering Multiple Working Conditions

Due to the advantage of high torque at low speed, permanent magnet vernier (PMV) motor has become an excellent candidate for low-speed direct-drive applications [1],
such as electric vehicles. With the increasing critical demand for electric vehicle drives, multiple design requirements have also been proposed for performance of electric vehicle drive
motors, including output torque and torque ripple [2]. Recently, many researchers have contributed to improving torque performances of PMV, mainly by the design of permanent magnet
and stator teeth [3][4]. Yet, it is noted that, current literature on improving motor performances would either increase output torque or reduce torque ripple, while the comprehensive
improvement of torque performances can hardly be achieved. Thus, in this paper, an airgap-harmonic-orientated partitioned design method is newly proposed for PMV motors. In the
proposed design method, considering the effect of different harmonics on torque performance, the torque designed region of rotor is artfully divided into torque enhanced region and ripple
reduced region. And, by the purposeful design of these two regions, output torque is increased while torque ripple is reduced effectively.
Fig. 1 shows the configurations of proposed and initial PMV motors. The airgap-harmonic-orientated partitioned design principle is presented in Fig. 2, providing theoretical guidance for
motor torque performance improvement. Fig. 3 shows the magnetic field and flux distributions of proposed motor. Meanwhile, based on partition design principle, the airgap flux density
waveforms, and the main airgap harmonic variations related to output torque and torque ripple are presented in Fig. 4 and Fig. 5 respectively. It can be seen from Fig. 6 that, by the
reasonable design of torque enhanced region and ripple reduced region, output torque of motor is significantly increased by 82.6% while torque ripple is reduced by 61.1% efficiently as
expected. Thus, by the proposed airgap-harmonic-orientated partition design method, improved output torque and reduced torque ripple can be realized effectively. The detailed theoretical
analysis and simulation results will be presented in the full paper. 

**References:** 

[1] Y. Ma and W. Fu, IEEE Trans. Magn, vol. 57, no. 6, pp. 1-5, June 2021. 
[2] B. Lee, Z. Zhu and L. Huang, IEEE Trans. Ind. Appl, vol. 55, no. 3, pp. 2510-2518, May-June 2019. 
[3] X. Zhu, M. Jiang and Z. Xiang, IEEE Trans. Ind. Electron, vol. 67, no. 7, pp. 5337-5348, July 2020. 
[4] L. Fang, D. Li and X. Ren, IEEE Trans. Ind. Electron, vol. 69, no. 6, pp. 6058-6068, June 2022. 

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Airgap Harmonic

Recently, flux modulated permanent magnet motors have aroused considerable attention, due to the merits of relatively high output torque at low speed. To further improve
motor torque output capability, double stator vernier permanent magnet (DS-VPM) motors have attracted increasing attention [1]. However, due to the relatively complicated relationship
among airgap flux harmonic, motor structure and performances, the difficulty and time burden of the optimization design of DSVPM motor is increased significantly [2]. Besides, during
actual motor manufacturing process, there exists many unavoidable design uncertainties, which would result in motor performance degradation [3]. Thus, it has been a hot but challenging
issue on how to realize high-efficiency optimization design of DS-VPM motor consider parameter fluctuation. In this paper, an airgap-harmonic-based multi-level robust optimization
design method is proposed for DS-VPM motor. By the proposed optimization method, motor performances can be improved comprehensively considering parameter fluctuation.
The structure of the investigated DS-VPM motor is shown in Fig. 1 (a), and corresponding design parameters of DS-VPM motor are presented in Fig. 1 (b). The flowchart of the proposed
airgap-harmonic-based multi-level robust optimization method is presented in Fig. 2. Firstly, the detailed relationship among design parameters, design parameters, and motor performances
are investigated, as shown in Fig. 3 and Fig. 4. Then, based on multi-objective genetic algorithm and response surface method, deterministic optimal design of DS-VPM motor is
determined. Furthermore, robust optimization method is utilized to achieve the robust optimal motor deign. Electromagnetic performances of the optimal DS-VPM motor are presented in
Fig. 5 and Fig. 6, while the normal distribution of the initial and final motor performances is presented in Fig. 7. Consequently, it is noted that that not only motor performances are
improved effectively, but the fluctuations of the motor performances are reduced significantly which verifies the effectiveness of the proposed robust multi-level optimization method.
More simulation and experimental results will be presented in the full paper. 

**References:** 

[1] W. Zhao, T. A. Lipo and B. -I. Kwon, IEEE Trans. Magn, vol. 51, no. 11, pp. 1-4, Nov 2015. 
[2] X. Zhu, M. Jiang and Z. Xiang, IEEE Trans. Ind. Electron, vol. 67, no. 7, pp. 5337-5348, July 2020. 
[3] M.-M. Koo, J.-Y. Choi and K. Hong, IEEE Trans. Magn, vol. 51, no.11, pp. 1-4, Nov 2015. 

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Multi Level Robust Optimization Design of Double

In-wheel motor is regarded as the most promising drive system of next generation electric vehicles in merit of high transmission efficiency, flexible control and compact
structure [1]. Since the in-wheel motor often operates under different conditions and possesses multiple external heat sources, electromagnetism-thermal analysis is essential during the
motor design stage [2]. Generally, the current electromagnetism-thermal analysis is based on finite element analysis (FEA), the large time-consumptions of this method brings challenges to
the design of this kind of motor [3]. Therefore, a rapid design method of in-wheel motor based on a common-node magneto-thermal bidirectional coupling network (CMTBCN) model is
proposed in this paper. In the CMTBCN model, some nodes of the motor are used as common nodes of the equivalent magnetic network (EMN) model and the equivalent thermal network
(ETN) model to avoid repeated modeling. Then the effect of temperature on the coercivity and permeability of permanent magnets is considered in EMN, the losses calculated by EMN at
initial temperature are used as the heat sources of ETN to calculate the new temperature. The temperature of each component of the motor and the electromagnetic performance under
different working conditions can be obtained more accurately by using the bidirectional coupling method. Finally, an in-wheel motor is designed and optimized based on CMTBCN model.
Fig. 1 (a) shows the 3D structure and parametric model of the in-wheel motor. Fig. 1 (b) shows the proposed common-node magneto-thermal bidirectional coupling network model. Fig. 2
(a) compared the airgap flux density and its harmonic analysis obtained by CMTBCN and FEA. Fig. 2 (b) compared the A-phase no-load flux linkage and back-EMF obtained by
CMTBCN and FEA at -20 and 100 degrees Celsius. Fig. 2 (c) shows the static temperature distribution of the in-wheel motor under the rated load obtained by FEA. Fig. 2 (d) shows the
prototype of stator and rotor of the proposed in-wheel motor.
More detailed analysis and experimental verification will be presented in the full paper. 

**References:** 

[1] P. Liang, F. Chai and Y. Yu, IEEE Transactions on Industrial Electronics, vol. 66, no. 2, pp. 1162-1171, Feb. 2019. 
[2] X. Chen and G. Li, 2020 13th International Conference on Intelligent Computation Technology and Automation (ICICTA), 2020, pp. 683-686. 
[3] X. Li, F. Shen and S. Yu, IEEE Transactions on Industrial Electronics, vol. 68, no. 8, pp. 6560-6573, Aug. 2021. 

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Optimization Design and Analysis of an In Wheel PM Motor Based on Common

In-wheel motors have been considered as one of the core technologies for the future developments of electric vehicles (EVs), where the outstanding feature is that the drive
motor is directly connected to the vehicle wheel [1]. It indicates that, to the EVs, the short transmission chain and high transmission efficiency can be achieved potentially by adopting the
in-wheel motor [2]. Yet, the direct-drive with in-wheel motor gaining advantages of power transmission, while it also makes the motor straightly faced with the complex drive environment,
such as the diverse operation conditions and road conditions. It means that, to the in-wheel motor, the problems of vibration and noise are more prominent and worthy of concern. This is
essential for realizing the high reliability and desirable comfort of EVs. Therefore, how to effectively suppress the vibrations and reduce noise is becoming a hot research field and full of
challenge. Then, a new perspective of radial electromagnetic force (REF) modulation is proposed for studying the vibration characteristic of a V-shaped PM in-wheel (VPM-IW) motor in
this paper. By purposely considering the modulation effect of REF into motor design, the electromagnetic vibration of VPM-IW motor is suppressed effectively.
Firstly, Fig.1(a) shows that the VPM-IW motor with the pole-slot combination of 40-pole/24-slot is selected as the design example. Fig.1(b) shows the deformation on the motor caused by
the different orders of REF. And Fig. 1(c) shows the principle of REF modulation. Then, Fig. 2(a)-Fig. 2(d) show the relationship between radial flux density (RFD) and REF. It can be
seen that, the dominant spatial order of REF, such as 4th, is generated by 4kth RFD harmonics. Hence, 4th REF can be suppressed by reducing 4kth RFD harmonics. Next, the multiobjective
genetic algorithm (MOGA) is adopted considering the force modulation effect. Fig. 2(g) to Fig. 2(n) show the comparison of performances. Fig. 2(m) and Fig. 2(n) show that the
optimal structure realizes the reduction of vibration and noise and the highest vibration peak appears around 4979 Hz, which is frequency of 4th mode.
The more detailed theoretical analysis and research results will be provided in the full paper. 

**References:** 

[1]W. N. Fu and S. L. Ho, IEEE Transactions on Magnetics, vol. 46, no. 1, pp. 127-134, Jan. 2010. 
[2] S. Zuo, F. Lin and X. Wu, IEEE Transactions on Industrial Electronics, vol. 62, no. 10, pp. 6204-6212, Oct. 2015. 

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Research on Vibration Characteristic of a V shaped PM In

I Introduction:
Typically, EVs adopt lithium-ion batteries as power supply. Therefore, constant current (CC) mode and constant voltage (CV) mode can be implemented for battery charging applications.
At present, various control strategies have been proposed. However, these methods require complex control strategies and additional components, often lead to increased switching
losses[1] and frequency bifurcation[2], and are difficult to achieve with zero phase angle input (ZPA). In this paper, a switchable hybrid compensation structure is designed to achieve loadindependent
output current and load-independent output voltage under ZPA conditions by switching the receiver-side compensation structure without additional devices and complex
control methods.
II Method and Discussion
A hybrid topology using different compensations in the receiver side, i.e., LC-LC compensation and LC-LCCL compensation is developed. Meanwhile, the compensation coil is integrated
into the receiving coil, the magnetic field is enhanced without any reactive power flow between the compensation and receiving coils, which can effectively improve the power
transmission distance, efficiency, and capacity. At a fixed frequency, no complicated control methods are required, and constant voltage and constant current can be achieved under ZPA
conditions. Besides, by optimizing the integrated coil and designing compensation parameters, the system can still maintain good CC-CV output characteristics when misalignment
happens.
III Conclusion
According to the experimental results, the wireless charging system can operate within 100mm misalignment in X-axis when the maximum fluctuations of the charging current IB in CC
mode and the charging voltage VB in CV mode are less than 7% which is consistent well with the theoretical analysis. Besides, the wireless charging system can achieve the maximum
efficiency at 93.43% with a 15-cm air gap when delivering 1442 W to the load. 

**References:** 

[1] Z. Li, C. Zhu, J. Jiang, K. Song, and G. Wei, “A 3 kW wireless power transfer system for sightseeing car supercapacitor charge,” IEEE Trans. Power Electron., vol. 32, no.
5, pp. 3301–3316, May. 2017. 
[2] C. W. Wang, G. A. Covic, and O. H. Stielau, “Power transfer capability and bifurcation phenomena of loosely coupled inductive power transfer systems,” IEEE Trans. Ind. Electron.,
vol. 51, no. 1, pp. 148–157, Feb. 2004 

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Analysis and Design of Constant Current and Constant Voltage Outputs of Integrated Coil Wireless EV Charging System

Numerical analyses should include the computation of magnetic hysteresis to estimate the performance of electric machines accurately. However, the finite element method
(FEM) requires significant time to simulate the hysteretic field because a hysteretic function modeled by, e.g., the Preisach model or the play model [1] must be called for each element and
time step.
The model order reduction (MOR) methods can effectively reduce the computation time of the FEM. This study aims to establish a new hysteretic MOR method for electric machines.
Specifically, we incorporate the hysteretic characteristics to the Cauer ladder network (CLN) method [2], a spatial mode decomposition technique showing superior convergence. It retains
physical interpretation, i.e., the inductances and resistances of the ladder network are directly computed from the decomposed modes. Therefore the nonlinear magnetic characteristics can
be directly incorporated [3].
The hysteresis effect is incorporated in the first inductor shown in Fig. 1. The magnetic fluxes flowing through the inductors are used as state variables. A semi-implicit time-marching
scheme is developed to reflect hysteretic properties without nonlinear iterations. Static I-φ loops are used to identify the scalar play model representing the first inductor. Those loops are
obtained by FE magnetostatic analysis, where the hysteretic behavior is calculated by the vector play model [1].
The reversible component is used to represent the second or later inductors, considering the characteristics of the minor loop [4]. The resistances of the CLN are prepared as functions of the
first stage magnetic flux with anhysteretic approximation.
3. Numerical analysis
An iron-cored inductor was analyzed, where a PWM voltage input was applied to the coil. Fig. 2 shows the locus of total current I1 and the first stage magnetic flux φ1 obtained by the
proposed CLN method (solid red line), which agreed with the transient FEM result (solid black line) better than the conventional equivalent circuit (dotted red line). 

**References:** 

[1] R. Mitsuoka et al., IEEE Trans. Magn., vol. 49, no. 5, pp. 1689–1692 (2013). 
[2] A. Kameari et al., IEEE Trans. Magn., vol. 54, no. 3, 7201804 (2017). 
[3] H. Eskandari and T. Matsuo, IEEE Trans. Magn., vol. 56, no. 2, 7505904 (2020). 
[4] Y. Shindo, T. Miyazaki and T. Matsuo, IEEE Trans. Magn., vol. 52, no. 3, 6300504, (2016). 

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A Model Order Reduction of Hysteretic Eddy current Fields in Electric Machines Using Cauer Ladder Network Method

In the marine environment, energy supply for distributed sensors is one of the main difficulties facing Internet of Things technology. Up to now, a variety of energy
harvesters have been created to convert wave kinetic energy into electrical energy through electromagnetic induction, piezoelectric effects and other principles. At present, although some
wave energy harvesters can collect wave energy and provide power for some low-power products, the overall output response frequency is greater than 1Hz[1], which is higher than the
most common wave frequency of 0.25Hz-1.0Hz. Some experts with extensive achievements in energy harvesters are committed to the research of low-frequency and broadband, however,
the output voltage of the designed wave energy harvester is too small[2], meantime the overall structure is extremely complex[3]. In addition, scholars have not explored the multidirectional
energy harvesting enough, and the existing studies are mostly based on the spherical friction structure[4], but spherical shapes can lead to lower energy density or material
utilization. In this paper, an electromagnetic wave energy harvester with a special double pendulum structure (as shown in Fig.1) has been proposed, the energy harvester can also capture
vibrational energy in multiple directions, responding to minimum frequencies of less than 0.25Hz and to currents with velocities of approximately 0.4m/s. This energy harvester can charge
a 220μF capacitor to about 32V in 50s with a peak power of 120mW under vibration conditions with a vertical height of 50 cm and a frequency of 1.0Hz, and can charge the capacitor to
about 16V in 50s at a horizontal speed of 0.72m/s (as shown in Fig.2). The results show that the wave energy harvester designed in this paper can respond to multi-directional vibrations,
and the response frequency is lower and wider, which is more favorable for wave energy harvesting. 

**References** 

[1] H. Liang, G. Hao and O. Z. Olszewski, International Journal of Mechanical Sciences., Vol. 219, 107130 (2022) 
[2] M. Li, X. Jing, Energy Conversion and Management., Vol. 244, 114466 (2021) 
[3] Z. Li, X. Jiang and P. Yin, Applied Energy., Vol. 302, 117569 (2021) 
[4] Q. Gao, Y. Xu and X. Yu, ACS Nano., Vol. 16, p.6781-6788 (2022) 

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Extremely Low Frequency Multi Directional Electromagnetic Wave Energy Harvester Based on Special Double Pendulum Structure

Variable flux memory machines (VFMM) using low coercive force (LCF) permanent magnets (PM) have been extensively investigated [1]-[5]. Normally, the series hybrid
magnet topology equipped with both PM with high coercive force (HCF) and LCF PMs to achieve high torque density and extended constant power speed range simultaneously, and two
kinds of PMs are magnetically connected in series to avoid unintentional demagnetization in LCF magnets. Nevertheless, the role LCF PM acts in the series magnetic circuit and its
potential effect on the air-gap flux density remain unclear. In this paper, the flux barrier effect of LCF PM on series VFMM is revealed and investigated, and an approach to preventing the
air-gap flux density drop is presented.
The conventional series hybrid magnet VFMM and interior permanent magnet (IPM) machine sharing identical usage of HCF PMs are shown in Fig.1. In Fig.1(e), the back-EMF amplitude
of the series VFMM is lower than that of the IPM machine. This is mainly due to the fact that the air-gap flux enhancement by the magnetomotive force of the LCF PM cannot compete
with the weakening effect by the magnetic reluctance of LCF PM. As a result, the flux barrier effect of the LCF PMs is identified, which further leads to a reduction of the torque density.
The topology of VFMM with dual-layer PMs is shown in Fig.1(c). The separation of the PMs weakens the barrier effect on the HCF PM and the bypass flux path reduces the equivalent
reluctance in the magnetic circuit. It can be observed in Fig.1 (d) that the air-gap flux density and flux variable range are improved. That is to say, the magnetic flux barrier effect of LCF
PM is reduced with the proposed dual-layer PM design.
The test results of the open-circuit back-EMF of the dual-layer series hybrid magnet VFMM prototype are shown in Fig.2. The experiments agree well with the FE-predicted results. The
detailed analysis, suppression methods of the flux barrier effect, and the detailed test results, will be given in the full paper. 

**References:** 

[1] V. Ostovic, "Memory motors," IEEE Ind. Appl. Mag., vol. 9, no. 1, pp. 52-61, Jan./Feb. 2003. 
[2] K. Sakai, K. Yuki, Y. Hashiba, N. Takahashi and K. Yasui, "Principle of the variable-magnetic-force memory motor," in Proc. Inter. Conf. Elec. Mach. System. (ICEMS), 2009, pp. 1-6. 
[3] N. Limsuwan, T. Kato, K. Akatsu and R. D. Lorenz, "Design and evaluation of a variable-flux flux-intensifying interior permanent-magnet machine," IEEE Trans. Ind. Appl., vol. 50,
no. 2, pp. 1015-1024, Mar./Apr. 2014. 
[4] H. Hua, Z. Q. Zhu, A. Pride, R. Deodhar and T. Sasaki, "A novel variable flux memory machine with series hybrid magnets," in Proc. 2016 IEEE Energy Conversion Congress and
Exposition (ECCE), 2016, pp. 1-8. 
[5] H. Yang, H. Zheng, H. Lin, Z. Q. Zhu and S. Lyu, "A novel variable flux dual-layer hybrid magnet memory machine with bypass airspace barriers," in Proc. 2019 IEEE International
Electric Machines & Drives Conference (IEMDC), 2019, pp. 2259-2264. 

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Analysis of flux barrier effect of LCF PM in series hybrid magnet variable flux memory machine

This paper presents the effects of magnetostriction of core loss and sound level on the design of power transformers and the results of analysis via the particle swarm
optimization (PSO) method. The core losses and the magnetostrictive forces in the ferromagnetic cores of transformers of various capacities, ranging from 15 MVA to 120 MVA, were
found to be significantly different from each other, as shown in Figure 1. Further, core loss was approximately proportional to capacity and core volume. However, the sound level
performance was not linear because of the squareness ratio (). This study utilized three types of soft core material: 30ZH105, 27ZH100 (Japan), and 27PH100 (Korea). The hysteresis loop
and magnetostriction were measured for various magnetic parameters. It was found that extremely high does not directly affect core loss. Whenwith respect to the sound level is high, the
experimental and design values are almost the same. The PSO method simulation results for transformers with several capacities, with respect to sound level and core loss performance,
were analyzed and compared with experimental values, as shown in Figure 2. 

**References:** 

[1] L. Bernard, , et. al., “Effect of stress on switched reluctance motors: A magnetoelastic finite-element approach based on multiscale constitutive laws,” IEEE Trans. on
Magnetics, vol. 47, no. 9, pp. 2171–2178, 2011. 
[2] Chang-Hung Hsu, et. al., “Reduction of vibration and sound-level for a single-phase power transformer with large capacity,” IEEE Trans. on Magnetics, vol. 51, no. 11, pp. 8403204-1-
4, 2015. 

![](https://s3.eu-west-1.amazonaws.com/underline.prod/uploads/markdown_image/1/image/129a1d95ef638cd48f494e1a6927987d.png)

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