• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.4
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• pp.49-55
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• 2014

In this paper, we propose the cogging toque reduction technique of the dual stator radial flux permanent magnet generator. The cogging toque is caused by the torque ripple increase and vibration and noise of the generator. And it is important factor determining cut-in speed of the small wind generator. To reduce cogging torque, permanent magnet displacement was studied. And the theory of the permanent magnet displacement was formulated and the cogging torque reduction according to the permanent magnet displacement was confirmed through the finite element method.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.828-831
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• 2003

This paper presents a novel design technique and characteristic analysis of Magnet for dual air-gap axial-flux type permanent-magnet synchronous generator. The process of magnet design is applied to the motor design and steady state analysis considering output voltage waveforms and magnetic flux waveforms. Design and construction of an axial-flux permanent-magnet generator with power output at 60 [Hz], 300[r/min] is introduced. Finite-element (FE) method is applied to analyze magnet shape characteristics. The results of FE analysis show generator is feasible for use with dual air-gap axial-flux permanent- magnet synchronous generator.

• Journal of Power Electronics
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• v.6 no.4
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• pp.290-297
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• 2006

Various methods have been discussed to reduce detent force in a tubular permanent magnet type linear single phase AC generator. In particular, the proposed methods depend on variations of the permanent magnet construction. These methods include two approaches in the form of sloped magnets, and conical magnets in addition to the conventional method of optimizing the magnet length. The undesired detent force ripples were calculated by a two dimensional Finite Element Method (FEM). Moreover, the generated electromotive force in the stator coils was calculated for each configuration of the permanent magnet. The experimental results agreed well with those obtained from the FEM-based simulations. Sufficient reduction in the detent force was achieved over the range of 40% while the root mean square of the output voltage was maintained. It was found that sloping the permanent magnet decreased the detent force and at the same time increased the generated rms voltage of the AC generator. The performance of the designed linear AC generator was evaluated in terms of its efficiency, total weight, losses, and power to weight ratio.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.3
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• pp.428-438
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• 2016

This paper shows the design of the 100 kW IPMSG for small hydraulic power generator. The high-efficient generator, method of the dual layer interior permanent magnet was studied to improve the method of the single layer interior permanent magnet, which is mostly used. Analysis of magnet arrangement and cogging torque was done by FEM. According to structure analysis of dual layer interior permanent magnet, the amount of usage of the permanent magnet was reduced and cogging torque was decreased as well. With these successful results, the high-efficient generator design was accomplished. Based on the results of the structure analysis, the test product was designed and manufactured. And the design values and performance outputs were compared and verified with success. Also, the economic feasibility was conducted based on the electric power generated from the test product installed at the site. By the B/C analysis, in case that only SMP was analyzed, B/C ratio was 1.24 at the discount ratio of 5.5%, which considered to be economically feasible. The study is expected to be used for the application of developing large scale high-efficient interior permanent magnet synchronous generator.

• Journal of Magnetics
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• v.19 no.3
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• pp.273-281
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• 2014

This paper presents an innovative design for a low-speed, direct-drive, axial-flux permanent-magnet (AFPM) generator with a coreless stator and rotor that is intended for application to small wind turbine power generation systems. The performance of the generator is evaluated and optimized by means of comprehensive 3D electromagnetic finite element analysis. The main focus of this study is to improve the power output and efficiency of wind power generation by investigating the electromagnetic and structural features of a coreless AFPM generator. The design is validated by comparing the performance achieved with a prototype. The results of our comparison demonstrate that the proposed generator has a number of advantages such as a simpler structure, higher efficiency over a wide range of operating speeds, higher energy yield, lighter weight and better power utilization than conventional machines. It would be possible to manufacture low-cost, axial-flux permanent-magnet generators by further developing the proposed design.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.3
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• pp.380-383
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• 2012

Small permanent magnet generator can be used not only as an emergency power source but also an exciting power source of generator for small generating systems because it does not need the external exciting power source. Especially the air-gap flux density of the buried PM synchronous generator can be increased more than that of the permanent magnet. In this study, the analysis of the small buried type PM synchronous generator is performed. From the phasor diagram considering armature resistance for exact analysis, analytic equations are induced and the efficiency, developed voltage, load current are calculated. The experimental results are compared with the calculated results for the appropriateness.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.74-75
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• 2017

This paper proposes a control scheme of the voltage ripple suppression for the permanent magnet exciter generator. The output voltage of the permanent magnet excitation generator is affected by the field current, load current and the engine speed. The engine speed can be controlled by the governor. But, the actual frequency is changed at the starting and a sudden load variation. As a result, output voltage overshoot and undershoot can decrease the power quality in the grid system. The proposed control scheme uses a frequency factor to control the field current of the generator for the voltage ripple reduction. Because of the linkage flux is proportional to the frequency, the instantaneous frequency can consider the linkage flux. The proposed control method shows the improved control performance for the permanent magnet excitation generator through simulation.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.455-458
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• 2001

This paper presents an axial flux permanent magnet synchronous generator with a high power-to-weight ratio, dedicated for small-scale gearless wind power generation plants. For this purpose, a specific design is necessary to meet the imposed requirements. In this paper the design technique for the specifications is presented. The aim of the paper is also to discuss some of the first obtained test results and the involved demagnetizing problem (i.e. short-circuit).

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.17-19
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• 2005

Variety of methods were discussed to reduce the cogging force in tubular permanent magnet type linear single phase AC generator. In paticular, the proposed methods depend on the variations of the permanent magnet construction. These methods Include two approaches in the form of sloped magnets, and conical magnets in addition to the conventional method of varying the magnet length. The undesired cogging force ripples were calculated by a two dimensional Finite Element Method(FEM). Moreover, the generated electromotive force in the stator coils was calculated fur each configuration of the permanent magnet. The experimental results agreed well with those obtained from the FEM-based simulations. Sufficient reduction in the cogging force was achieved over the range of 40% while the root mean square of the output voltage was maintained. It was found that the sloping the permanent magnet decreased the cogging force and at the same time increased the generated rms voltage of the AC generator. The performance of the designed linear AC generator was evaluated in terms of its efficiency, total weight, losses, and power to weight ratio.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1002-1006
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• 2015

In this paper, design and analysis of permanent magnet synchronous generator for ocean thermal energy conversion (OTEC) considering magnetically coupled turbine-rotor system is discussed. In particular, the rotor dynamics considering bearing span and journal shaft diameter is highlighted. The two topologies of permanent magnet synchronous generator with magnetic coupling are employed for comparison of computed rotor dynamics and generating characteristics. The analysis results show that the critical speed of the turbine-rotor system is higher when the rotor is coupled by magnetically coupling. Finally, the experimental results confirmed the validity of the proposed design and analysis scheme and successful development.