• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1025-1034
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• 2015

This paper presented an improved analytical method for calculating the open-circuit magnetic field in the surface-mounted permanent magnet machines accounting for slots and eccentric magnet pole. Magnetic field produced by radial and parallel permanent magnet is equivalent to that produced by surface current according to equivalent surface-current method of permanent magnet. The model is divided into two types of subdomains. The field solution of each subdomain is obtained by applying the interface and boundary conditions. The magnet field produced by equivalent surface current is superposed according to superposition principle of vector potential. The investigation shows harmonic contents of radial flux density can be reduced a lot by changing eccentric distance of eccentric magnet poles compared with conventional surface-mounted permanent-magnet machines with concentric magnet poles. The FE(finite element) results confirm the validity of the analytical results with the proposed model.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.4
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• pp.429-435
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• 2013

This paper proposes a sensorless speed control based on a novel extension of the torque producing flux (active flux) observer for the surface mounted permanent magnet synchronous machines (SPMSM) without additional high frequency signal injection. From the estimated torque producing flux, the rotor position and speed can be calculated at low speed due to their independency. Therefore, no rotor position sensor is required. Two approaches of the torque producing flux observer are presented and compared. The results show the stability and robustness of the expansion of the torque producing flux observer at low speed for the SPMSM.

• Journal of Magnetics
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• v.16 no.1
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• pp.64-70
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• 2011

Surface-mounted permanent magnet (PM) machines were examined experimentally and theoretically, through power loss measurements and calculations. Windage, friction and copper losses were calculated using simple analytical equations and finite element (FE) analyses. Stator core losses were calculated by determining core loss coefficients through curve-fitting and magnetic behavior analysis through non-linear FE calculations. Rotor eddy current losses were calculated using FE analyses that considered the time harmonics of phase current according to load. Core, windage and friction open-circuit losses and copper loss were determined experimentally to test the validity of the analyses.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.740-741
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• 2015

This paper presents the design and dynamic analysis of surface-mounted type variable flux permanent magnet(VFPM) machines. VFPM machines with a low-coercive-force (LCF) magnetic material have been studied extensively for their potential to improve the efficiency and extend the flux-weakening range of permaennt magnet (PM) machines. In order to implement the design of the VFPM machines effectively, we perform a characteristic analysis of the LCF magnet with respect to design parameters. The analysis results of the designed VFPM machines are compared with measured results, and the validity of the design of the VFPM machines is confirmed.

• Journal of Electrical Engineering and Technology
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• v.12 no.2
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• pp.778-789
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• 2017

This paper presents an improved subdomain method to predict the magnet field distributions and electromagnetic performance of the surface-mounted permanent magnet (SPM) machines with static or dynamic eccentricity. Conventional subdomain models are either based on the scalar magnet potential to predict the rotor eccentricity effect or dependent on the magnetic vector potential without considering the eccentric rotor. In this paper, both the magnetic vector potential and the perturbation theory are introduced in order to accurately calculate the effect of rotor eccentricity on the open-circuit and armature reaction performance. The calculation results are presented and validated by the corresponding finite-element method (FEM) results.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1674-1681
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• 2015

This paper presented an improved analytical method for calculating armature-reaction field in the surface-mounted permanent magnet machines accounting for opening slots. The analytical model is divided into two types of subdomains. The current of the armature is centralized in the center of the slots. The field solution of each subdomain is obtained by applying the interface and boundary conditions of the model. Two 30-pole/36-slot prototype machines with different slot-opening width are used for validation. The FE (finite element) results confirm the validity of the analytical results with the proposed model. The investigation shows that the wider the slot-opening width is, the smaller the peak value of radial and circumferential components of flux density, and the analytical armature-reaction field produced by centralized current in the slots is similar with the armature-reaction field produced by distributed current in the slots in the FE.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.586-589
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• 2001

In Case of High speed PM machines with surface-mounted magnet. A rare-earth PM with high remanence flux density is used on the rotor. Therefore, It is very difficult to adhesion and assemble PM on the surface of rotor, because of very repulsive force between magnets. So, for solving this problem, rotor with surface-mounted magnet is wholly magnetized after mounting magnetic-material on the surface. In this paper, In order to Magnetize rotor with surface-mounted PM, magnetizing machine is designed, analyzed and simulated for large PM machines using the 1dimensional analytical method and 2dimensional finite element method. (20-FEM).

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.3
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• pp.138-145
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• 2006

It is well known that the accurate calculation of the field distribution is essential for the design of electrical machines. The analytical techniques for electromagnetic field can quickly and exactly determine airgap magnetic field distribution in electrical machines. Many analytical techniques have been investigated to predict the magnetic field distribution in PM machines equipped with permanent magnets. Using the analytical technique by transfer relations, D. L. Trumper and K. R. Davey already presented the design and analysis of linear permanent-magnet machines and induction machines, respectively. Using the transfer relations (Melcher's general methodology) to describe electromagnetic phenomena, this paper deals with the analysis on the magnetic field distribution due to PM and winding current, the induced voltage and the static torque characteristics in surface-mounted slotless type permanent magnet machine. The validity of the analysis results is confirmed by finite element (FE) analysis.

• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.1
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• pp.38-44
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• 2015

This paper presents the sensorless drive method for mono inverter dual parallel (MIDP) surface mounted permanent magnet synchronous motor (SPMSM) drive system. MIDP motor drive system is a technique that can reduce the cost of the multi motor driving system. To maximize this merit of the MIDP motor drive system, the sensorless technique is essential to eliminate the position sensors. This paper adopts an appropriate sensorless method for MIDP SPMSM drive system, which uses the reduced order observer and phase locked loop (PLL) to reduce the calculation burden. The I-F control method is implemented for start-up and low speed operation. The validity and performance of the proposed algorithm are shown via experiments with 600-W SPMSMs.

• Journal of Electrical Engineering and Technology
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• v.11 no.1
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• pp.150-156
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• 2016

This paper compares the performances of permanent-magnet synchronous (PMS) and permanent-magnet vernier (PMV) machines for low-speed and high-torque applications. For comparison with the PMS machines, we consider two types of the PMV machine. The first one has surface-mounted permanent magnets (PMs) on the rotor and the other has PMs inserted on both sides of the stator and rotor. The PMS and PMV machines are designed to meet the condition of equal output power per unit volume. We analyze the magnetic fields of the machines using a two-dimensional finite element analysis (FEA). We then compare their performances in terms of the generated torque characteristics, power factor, loss, and efficiency.