• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.256-261
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• 2017

This paper deals with the experimental evaluation on power loss of a double-side permanent magnet synchronous motor/generator (DPMSM/G) applied to a flywheel energy storage system (FESS). Power loss is one of the most important problems in the FESS, which supplies the electrical energy from the mechanical rotation energy, because the power loss decreases the efficiency of energy storage and conversion of capability FESS. In this paper, the power losses of coreless DPMSM/G are separated by the mechanical and rotor eddy current losses in each operating mode. Moreover, the rotor eddy current loss is calculated by the 3-D finite element analysis (FEA) method. The analysis result is validated by separating the power loss as electromagnetic loss and mechanical loss by a spin up/down test.

• 드라이브 ㆍ 컨트롤
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• 제10권1호
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• pp.21-28
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• 2013

Wind energy has been more and more important and contributive in the energy utilization of the world. This paper proposed a novel method for Wind Energy Conversion System (WECS), in which a secondary control hydrostatic transmission (SC-HST) with two hydraulic accumulators, were employed for wind energy conversion system. This approach can absorb the excessive power of turbine, keep the generator from over-speed and maintain the speed of generator in low speed of turbine. A PID controller was designed for speed control to track a predefined speed. The simulation results indicated that the speed of the generator was ensured with the relative error less than 2%; and the efficiency of the proposed system was 70.4%.

• Journal of Electrical Engineering and information Science
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• 제1권1호
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• pp.58-69
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• 1996

This paper presents a new approach to derive an energy integral based on an Equivalent Mechanical Model(EMM), which is developed by introducing imaginary springs for line resistances. The proposed EMM shows that phasor currents and voltages are directly analogous to the two-dimensional force and displacement vectors, respectively. Through rigorous energy analysis of the proposed EMM, an exact energy integral expression is derived for multimachine systems, and several useful theorems are developed to derive an energy integral for power systems with detailed generator models the energy integral exactly reflects the internal resistance, saliency and flux-decaying effects of the generator. Finally, an illustrative example is given for a multimachine system adopting the Eq'-model for generators, which shows that the consideration of a detailed generator model does not aggravate the complicacy of the direct method of stability analysis in multimachine systems.

• 신재생에너지
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• 제6권4호
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• pp.41-49
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• 2010

Over the last decade, wind turbine industry has rapidly increased around world. These days many parts of the wind generators are induction generator. But it has some problems such as gearbox failure, rotor excitation and maintenance. Thus many manufacturers are considered permanent magnet synchronous generator named PMSG and direct drive. PMSG uses NdFeB magnet has many the advantage compare with induction generator. In this study, 3MW class outer rotor type PMSG for wind turbine is proposed. The generator features 2.6m stator outer radius, 1200mm stator length, 81 pole pairs, 14 rated rpm, 42kN/$m^2$ shear force density and 94.2% efficiency. Design and analysis generator using FEM program. Then calculate and derivate no load voltage, losses, conductor temperature. To reduce total harmonic distortion and cogging torque, the stator is applied the stator skewing. And to evaluate the designed generator, compare with other generators by active mass per rating torque and torque density.

• 신재생에너지
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• 제9권4호
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• pp.19-24
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• 2013

In order to analyze the characteristics of tidal current power generation system, we measured output power in M-G Set (Motor-Generator Set) and MATLAB/Simulink. We installed M-G Set (Motor-Generator Set) and did a simulation using MATLAB/Smulink. The simulation consisted of the tidal current turbine, PMSG, converter, and three-phase PWM inverter. Also, the speed control of the generator was performed using machine side converter. And we measured output voltage, current, power of the generator and the output power of three-phase PWM inverter.

• Journal of international Conference on Electrical Machines and Systems
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• 제3권1호
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• pp.15-19
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• 2014

As the space of the wind power generator stator end is limited, it is difficult for us to place the inner evaporative cooling system in it. We use the non-overlapping concentrated windings scheme to solve the placing and cooling problem. The characteristic of a 5MW direct-driven permanent magnet generator with non-overlapping concentrated windings were analyzed under no-load, rating-load and short-circuit by (Finite Element Method) FEM for verification of design. We studied the connection methods of the stator windings and designed the end connection member. The heat dissipation of the stator end was simulated by FEM, the result showed that the end cooling could satisfy the wind generator operation needs. These results show that the direct-driven permanent magnet wind power generators with non-overlapping concentrated windings and inner evaporative cooling system can solve the cooling problem of wind power generator, and obtain good performance at the same time.

• Nuclear Engineering and Technology
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• 제29권1호
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• pp.15-24
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• 1997

The design and evaluation of a digital U-tube steam generator level controller of nuclear power plants, which uses model-based compensators to offset the inverse response behavior of water level, is described. Included is a review of steam generator level dynamics, a simulation model that replicates the effects of feedwater and steam flowrate as well as temperature on steam generator level, the design of both the compensators and the overall controller, and the results of simulation studies in which the performances of this model-based controller and existing analog ones were compared. The proposed digital steam generator level controller is stable and its use significantly improves the controllability of steam generator level.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.366-368
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• 2007

Mr. Hur has developed the 7500KW permanent magnet synchronous generator. The 7500KW generator has dual blade system with vertical axis type generation module. The 7500KW generator will generating that it is too expensive and construction payment. The advantages of dual blade system are cheap in generation with better efficiency, and safety compact structure. But also this system has the expensive slide ring for to distribute electrical power.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 추계학술대회 논문집
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• pp.391-394
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• 2008

Global warming and air pollution have increased the amount $CO_2$ in the atmosphere. In order to decrease the amount of $CO_2$, lots of researches are conducted toward using Hydrogen energy. Because of its high efficiency energy level and environmental friendly features, many companies have researched on developing hydrogen engine system and distributed generation system. Especially, the focus of this research provides the operation method of linear generator for hydrogen fuel combustion linear engine. During an ignition, linear generator is operated by motor to create the initial condition of engine combustion. Once the engine combustion is stabilized, the generator supplies electric power to grid. In order to stabilize the engine, linear generator is required to control mover frequency, direction, and force; Hence the PCS(Power Conversion System) place three H-bridge type inverter stacks in parallel to control phase current independently. As well, by using Back-to-Back method, it can receive electric power from both end.

• 전기학회논문지
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• 제65권5호
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• pp.724-729
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• 2016

Nowadays high-cost energy storage system using flywheel or secondary battery is applying to hybrid generation system with WT(Wind Turbine) and diesel generator in island areas for stable operation. This paper proposes an operating algorithm and modeling method of the hybrid generation system that can operate for variable wind speed and load, which is composed of energy storage system, variable-speed PMSG(Permanent Magnet Synchronous Generator) WT and diesel generator applied in island areas. Initially, the operating algorithm was proposed for frequency and voltage to be maintained within the proper ranges for load and wind speed changes. Also, the modeling method is proposed for variable speed PMSG WT, diesel generator and BESS(Battery Energy Storage System). The proposed operating algorithm and modeling method were applied to a typical island area. The frequency and voltage was kept within the permissible ranges and the proposed method was proven to be appropriate through simulations.