• Title, Summary, Keyword: rotor loss

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A Study on Rotor Eddy Current Loss and Thermal Analysis of PM Synchronous Generator for Wind Turbine (풍력터빈 PM형 동기발전기의 와전류손실과 열 해석에 관한 연구)

  • Choi, Man Soo;Chang, Young Hag;Park, Tae Sik;Jeong, Moon Seon;Moon, Chae Joo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.11
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    • pp.1575-1581
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    • 2014
  • In this paper, eddy current loss, iron loss and heat transfer of PMSG with 2,000kW capacities were analyzed for wind turbine. The PMSG with 3 split magnet was analyzed using ansoft maxwell commercial program and, generator was tested by Back to Back converter with no load condition at laboratory. Rotor surface temperature was measured by Pt100 sensors for investigating heat transfer from rotor to atmosphere. The simulation results shows 27.4kW eddy current loss in no load condition and 50.2kW eddy current loss in rated load condition with 3 split magnet, and also shows 4.3kW iron loss in no load condition and 7.3kW iron loss rated load condition. The heat transfer coefficient of convection between rotor surface and atmosphere was investigated by $9.6W/m^2{\cdot}K$. Therefore the heat transfer from rotor to atmosphere was about 17kW(54%) and from rotor to air-gap was about 14.6kW(46%) in no load condition. It is identified that the cooling system for stator have to include the 46% of iron loss, and heat dissipation structure of rotor surface have to be suggested and designed for efficiency improvement of generator.

An Experimental Study of the Performance Characteristics with Four Different Rotor Blade Shapes on a Small Mixed-Type Turbine

  • Cho Soo-Yong;Cho Tae-Hwan;Choi Sang-Kyu
    • Journal of Mechanical Science and Technology
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    • v.19 no.7
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    • pp.1478-1487
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    • 2005
  • A small mixed-type turbine with a diameter of 19.9 mm has been substituted for a rotational part of pencil-type air tool. Usually, a vane-type rotor is applied to the rotational part of the air tool. However, the vane-type rotor has some problems, such as friction, abrasion, and necessity of accurate assembly etc.,. These problems make the life time of the vane-type air tool short, but air tools operated by mixed-type turbines are free of friction and abrasion because the turbine rotor dose not contact with the casing. Moreover, it is assembled easily because of no axis offset. These characteristics are merits for using air tools, but loss of power is inevitable on a non-contacting type rotor due to flow loss, tip clearance loss, and profile loss etc.,. In this study, four different rotors are tested, and their characteristics are investigated by measuring the specific output power. Additionally, optimum nozzle location against the rotor is studied. Output powers are obtained through measured pressure, temperature, torque, rotational speed, and flow rate. The experimental results obtained with four different rotors show that the rotor blade shape greatly influences to the performance, and the optimum nozzle location exists near the mid span of the rotor.

Evaluation of Tip Leakage Loss and Reduction of Efficiency of Axial Turbomachinery Using Numerical Calculation (수치계산에 의한 축류터보기계의 회전차 익말단의 누설손실과 효율저하에 대한 평가)

  • Ro, Soo-Hyuk;Cho, Kang-Rae
    • The KSFM Journal of Fluid Machinery
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    • v.2 no.1
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    • pp.73-80
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    • 1999
  • Leakage vortices formed new blade tip causes an increase of total pressure loss near the casing endwall region and as a result, the efficiency of rotor decreases. The reduction of rotor efficiency is related to the size of the tip clearance. In this study, the three-dimensional flowfields in an axial flow rotor were calculated by varying the tip clearance under various flow rates, and the numerical results were compared with experimental ones. The effects of tip clearance and attack angle on the leakage vortex and overall performance, and the loss distributions were investigated through numerical calculations. In this study, tip leakage flow rate and total pressure loss by tip clearance were evaluated using numerical results and approximate equations were presented to evaluate the reduction of rotor efficiency by tip leakage flow.

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Evaluation of Flowfield and Flow Losses insied Axial Turbomachinery Using Numerical Calculation [Evaluation of Tip Leakage Loss and Reduction of Efficiency by Tip Clearance] (수치계산에 의한 축류터보기계의 유동장과 유동온실의 평가 III [회전차 익말단의 누설손실과 효율저하에 대한 평가])

  • Ro, Soo-Hyuk;Cho, Kang-Rae
    • 유체기계공업학회:학술대회논문집
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    • pp.240-247
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    • 1998
  • Leakage vortices formed near blade tip causes an increase of total pressure loss near casing endwall region and as a result, the efficiency of rotor decreases. The reduction of rotor efficiency is related to the size of tip clearance. In this study, the three-dimensional flowfields in an axial flow rotor were calculated with varying tip clearance under various flow rates, and the numerical results were compared with experimental ones. The effects of tip clearance and attack angle on the leakage vortex and overall performance, and the less distributions were investigated through numerical calculations. In this study, tip leakage flow rate and total pressure loss by tip clearance were evaluated using numerical results and aprroximate equations were presented to evaluate the reduction of rotor efficiency by tip leakage flow.

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Loss Minimization of DFIG for Wind Power Generation

  • Abo-Khalil, Ahmed G.;Park, Hong-Geuk;Lee, Dong-Choon;Lee, Se-Hyun
    • Proceedings of the KIPE Conference
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    • pp.315-317
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    • 2007
  • This paper proposes a loss minimization algorithm for doubly-fed induction generator (DFIG) by controlling the stator reactive power. The proposed strategy directly controls the rotor current to achieve the operating point of minimum generator loss and maximum power point tracking. The maximum power is obtained by tracking the q-axis rotor current with generator speed variation and the minimum generator loss is achieved by controlling the d-axis rotor current. Experimental results are shown to verify the validity of the proposed scheme.

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Numerical Analysis on the Blade Tip Clearance Flow in the Axial Rotor (III) - Evaluation of Tip Leakage Loss and Reduction of Efficiency near Blade Tip Clearance Region of a Rotor - (축류 회전차 익말단 틈새유동에 대한 수치해석 (III) - 회전차 익말단의 누설손실과 효율저하에 대한 평가 -)

  • Ro, Soo-Hyuk;Cho, Kang-Rae
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.23 no.9
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    • pp.1113-1120
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    • 1999
  • Leakage vortices fonned near the blade tip cause an increase of total pressure loss near the casing endwall region and as a result, the efficiency of rotor decreases. The reduction of rotor efficiency is related to the size of tip clearance. In this study, the three-dimensional flow fields in an axial flow rotor were calculated with varying tip clearance under various flow rates, and the numerical results were compared with experimental ones. The effects of tip clearance and the of attack on the leakage vortex and overall performance, and the los9 distributions were investigated through numerical calculations. In this study, tip leakage flow rate and total pressure loss due to the tip clearance were evaluated using numerical results and approximate equations were presented to evaluate the reduction of rotor efficiency due to the tip leakage flow.

Experimental Evaluation on Power Loss of Coreless Double-side Permanent Magnet Synchronous Motor/Generator Applied to Flywheel Energy Storage System

  • Kim, Jeong-Man;Choi, Jang-Young;Lee, Sung-Ho
    • Journal of Electrical Engineering and Technology
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    • v.12 no.1
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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.

Design Solutions to Minimize Iron Gore Loss in Synchronous Reluctance Motors Using Preisach Model & FEM (프라이자흐 모델이 결합된 유한요소 해석을 이용한 동기형 릴럭턴스 전동기의 철손 최소화 회전자 구조 설계)

  • Lee, D.D.;Lee, M.M.;Sim, J.M.;Lee, J.H.
    • Proceedings of the KIEE Conference
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    • pp.138-140
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    • 2002
  • This paper deals with an automatic design procedure for the minimization of iron core loss in a synchronous reluctance motor (SynRM). The focus of this paper is the design relative to hysteresis loss on the basis of rotor shape of a SynRM in the same torque density. The coupled Finite Elements Analysis (FEA) & Preisach model have been used to evaluate the iron core loss with the rotor shape. The proposed procedure allows to define the rotor geometric dimensions starting from an existing motor or a preliminary design. The iron loss has been reduced with a rotor design variation.

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Loss Modeling in order to Predict the Efficiency Performance of Induction Motor Drive System (유도전동기 드라이브 시스템의 효율성능을 예측하기 위한 손실 모델링)

  • 정동화;박기태;이정철
    • Journal of the Korean Society of Safety
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    • v.15 no.4
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    • pp.56-61
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    • 2000
  • The precise and reliable loss model for induction motor and converter system is very important in order to predict the efficiency performance of variable speed drives. This paper proposes an accurate loss model of induction motor and converter system. The motor losses, such as stator and rotor copper loss, core loss and stray loss, are considered for fundamental and harmonic frequencies. Also considered are the skin effect on rotor resistance, temperature effect on bath stator and rotor resistance, magnetizing inductance saturation, and friction and windage loss. All the above features are incorporated in a synchronous frame dynamic d-q equivalent circuit. The converter system, consisting of a diode rectifier and PWM transistor inverter, is modeled accurately for conduction and switching losses. Validity of the models, in both steady state and transient conditions, is verified by simulations.

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Investigation on Performance Characteristics of IPM for Electric Vehicles Considering Driving Conditions and Pole-Slot Combinations

  • Seo, Jangho
    • Journal of Magnetics
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    • v.18 no.3
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    • pp.268-275
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    • 2013
  • This paper shows the characteristics of performance for interior permanent magnet machine (IPM) considering driving conditions such as maximum torque per ampere (MTPA) and flux-weakening control especially in terms of harmonic loss. In particular, based on finite element analysis (FEA), permanent magnet (PM) eddycurrent loss and the harmonic iron loss have been computed where the models have been intentionally designed to identify the effects of pole-slot combinations on the loss while maintaining the required power for electric vehicle. From the analysis results, it was shown that the rotor iron loss and PM eddy-current loss of machine employing fractional slot winding are extremely large at load condition. Furthermore, it was revealed that the harmonic iron loss at high-speed operation is mainly distributed over stator teeth and rotor surface, which may aggravate cooling system of the rotor structure in the vehicle.