• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.1
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• pp.1-7
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• 1998

Due to the increase in capacity of auxiliary machinery in power plant, the importance of energy saving has been greatly emphasized. If the speed of fans or pumps is controlled in accordance with the variation of load, large electric energy can be saved. Large capacity inverter, 2MVA GTO inverter, has been developed by operating two of 1MVA unit inverters in parallel. The parallel operation of the unit inverter is accomplished through two output transformers of which the secondary windings are connected in series. The system is composed of one control cubicle, one rectifier cubicle and 2 unit inverter cubicles. This inverter system was applied to the sea water lift pump(SLP) driven by a 6.6KV 1500KW induction motor in Seo-Inchon power plant to save the electric energy. The parallel operation of inverters by 180 degrees apart in switching frequency helps to reduce the harmonic components.

• Journal of the Korean Society for Railway
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• v.10 no.6
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• pp.650-654
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• 2007

Induction motors are widely used as a source of driving force in electric vehicles and pulse width modulation (PWM) inverters are applied to their operation. The issue is that insulation of inverter-fed induction motors (IFMs) are more stressed than in line-powered motors by transient voltages. This paper dealt with experimental results on transient voltage produced by the PWM operation of an induction motor. The peak and the dv/dt of transient voltage depending on the length of power feeding cable and operating frequency were investigated. In the experiment, transient voltages up to 3.3PU of the rated-inverter voltage were recorded for the cable length of 50m. As the cable length is increased, the peak voltage appeared at the motor terminals increases. This phenomenon can be explained by the reflection and the transmission of travelling wave. Consequently, special care for the cable length between the motor and the inverter should be taken in the use of IFM to ensure the full life of insulation system.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.67-68
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• 2010

다중동력시스템은 하나의 엑셀에 두개의 모터를 연결하여 구동하는 시스템으로 차량의 부하가 적은 경우 한대의 모터로만 운전을 하고 경사로의 등판이나 화물의 양이 증가해 부하가 커지는 경우 두 대의 모터를 운전하는 병렬 동력원을 가지는 차량 제어 시스템을 말한다. 다중동력시스템에서 PMSM의 제어는 전류 제어와 속도 제어로 구현이 가능하다. 본 논문에서는 다중동력 시스템에 적용이 가능한 인버터에 대해 벡터 제어 알고리즘의 PSIM 시뮬레이션과 시험을 수행하여 제안한 제어기의 유용성을 검증하였다.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.3
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• pp.267-275
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• 2007

This paper presents about energy input and output modeling for a flywheel energy storage system that can store and supply mechanical energy, which is emerging as one of clean energy sources, and the analysis and control of a PWM inverter system. Moreover, this paper describes flywheel's characteristics related to variations of mechanical and electrical parameters like as voltage and current versus speed characteristics formed as numerical formula and thus simulate behaviour-status of flywheel energy. Also for comparison and analysis between PI control and PDFF control, the modeling, design and analysis to the single-phase full bridge inverter with double loop feedback control is accomplished through numerical description and simulation. Finally, under load condition 0.1[pu], 1[pu]. it is validated that harmonic characteristics for voltage and current wave is controlled within 5% below even dynamics condition.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.4
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• pp.661-668
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• 2024

Based on the topology of the direct-drive permanent magnet synchronous wind power grid-connected system based on the power electronics full-power converter, the wind turbine model and the grid-side inverter model were studied, and the machine-side rectifier control based on current and speed double closed loops was designed. strategy, as well as a grid-side inverter control strategy based on current and voltage double closed loops, implementing a two-level back-to-back double closed-loop full control strategy. A system simulation model was built using Matlab/Simulink, and the operation of the unit was simulated when the wind speed changed step by step. The grid-connected current with the same phase and good sinusoidal nature of the grid voltage was output. The grid-connected system ran stably and efficiently. The simulation results The validity and rationality of the model, as well as the correctness and feasibility of the control strategy were verified.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.259-260
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• 2011

본 논문은 벅-부스트 컨버터의 듀티비 제어를 통해 풍력발전시스템이 최대 효율을 갖도록 MPPT (Maximum power point tracking) 알고리즘을 구현하고, 발전된 전력을 계통으로 전달하기 위한 인버터 제어방법 및 시스템 구성을 제안한다. 특히 풍속정보와 발전기 속도를 제거하여 센서로 인한 단점들을 배제하였고, 제안한 풍력발전시스템과 알고리즘의 유용성을 시뮬레이션을 통해 검증한다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.1
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• pp.45-50
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• 1998

In recent year, inverters and cycloconverters system are widely used for fed induction motor drives. Motor drives by cycloconverter is possible to frequency have been directly changed without AC/DC converter, so that circuits is simpler than inverter. A aims of this paper is the control strategy and hardware design for vector control system by cycloconverter fed induction motor drives. In this paper, Algorithm of vector control is derivlid from the model of controlled current source-fed induction motor. Vector control system is implemented using these algorithm and a pulse width controled cycloconverter using a SCR. Cycloconverter of vector control system is controlled by pulse width of SCR's trigger signal. pulse width is controlled primary command current $li_1l$ and frequency TEX>$\omega_1$..

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.286-287
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• 2017

본 논문은 철도 차량 구동용 IPMSM 제어를 위한 속도 영역별 PWM 알고리즘을 제안한다. 철도 차량의 고속영역 제어는 인버터 전압 이용률을 최대화 할 수 있는 1-Pulse 제어 기법이 요구된다. 그러나, SPWM을 이용한 비동기 1-Pulse 제어는 출력 전류의 불균형을 초래한다. 따라서, 고속영역 제어를 위해 동기화 시킨 후 SPWM을 이용한 1-pluse 제어는 필수적이다. 본 논문에서는 비동기 모드로 제어를 시작하여 과변조 영역 이전에 지령 전압과 삼각파 주파수를 동기화 시킨 후 고속 영역운전을 하는 PWM 알고리즘을 제안한다. 본 논문에서 제안하는 알고리즘은 시뮬레이션으로 검증한다.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.38 no.1
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• pp.1-13
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• 2001

Due to the friction characteristics of cylinders and the rail of a passenger car, in the elevator actuated with hydraulic systems, there exist dead zones, which can not be controlled by a PID controller. To overcome the drawbacks, in this paper, we first try a hybrid controller which switches between a fuzzy logic controller and a PID controller. However, because the hybrid control scheme uses only a single type controller, except the switched layer, the high control performance can not be achieved. To solve this problem, we propose a new type fuzzy hybrid control scheme, which outputs of the output mixer arc controlled by a fuzzy logic. The hydraulic elevator system controlled by inverters has more then one switched layers due to the highly nonlinear characteristics. The proposed fuzzy hybrid control scheme achieves improved control performances by using both controllers with weighted outputs depend on the system status, to achieve improved control performances. The effectiveness of the proposed control scheme arc shown by simulation results, which the proposed fuzzy hybrid control method yields good control performance not only in the zero crossing speed region but also in the overall control region including steady-state region.

• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.159-160
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• 2016

본 논문에서는 최근 건설기계용으로 연구되고 있는 E-TCS의 Power Electronics System에 대한 Topology와 제어방법을 제안한다. 디젤엔진과 같이 사용되는 E-TCS는 압축기와 터빈 그리고 요구되는 회전속도로 고속회전 및 발전이 가능한 모터와 이를 제어하는 인버터로 구성된다. 기존의 E-TCS를 위한 Power Electronics System의 경우 배터리의 전압강압으로 인버터의 전류량이 증가하여 Power Electronics System 및 모터의 Volume이 커지는 단점이 있으며, 특허가 존재하여 사용이 어렵다. 본 논문에서는 이와 같은 단점을 개선한 E-TCS를 위한 새로운 Topology 구성 및 제어방식을 제안한다.