• Journal of the Korean Solar Energy Society
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• v.38 no.2
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• pp.1-13
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• 2018

This paper deals with the NREL (National Renewable Energy Laboratory) 5-MW reference wind turbine. The controller which include MPPT (Maximum power point tracking) control algorithm and tower load reduction control algorithm was designed by MATLAB Simulink. This paper propose a tower damper algorithm to improve the existing tower damper algorithm. To improve the existing tower damper algorithm, proposed tower damper algorithm were applied the thrust sensitivity scheduling and PI control method. The thrust sensitivity scheduling was calculated by thrust force formula which include thrust coefficient table. Power and Tower root moment DEL (Damage Equivalent Load) was set as a performance index to verify the load reduction algorithm. The simulation were performed 600 seconds under the wind conditions of the NTM (Normal Turbulence Model), TI (Turbulence Intensity)16% and 12~25m/s average wind speed. The effect of the proposed tower damper algorithm is confirmed through PSD (Power Spectral Density). The proposed tower damper algorithm reduces the fore-aft moment DEL of the tower up to 6% than the existing tower damper algorithm.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.5
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• pp.525-529
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• 2009

Most of FLC received input data from error e and change-of-error e' with no relation with system complexity. Basic scheme follows typical PD and PI or PID Controller and that has been developed through fixed ME In this paper, We studied the relationship between MF and system response and system response through changing Fuzzy variable of consequence MF and propose the simple FLC using this relationship. The response of FLC is changed according to the width of Fuzzy variable of consequence MF. As changing the Fuzzy variable of consequence MF shows various nonlinear characteristic, we studied the relation between response and MF using analytical method. We designed the effective FLC using three-variable MF and nine rules and took simulation for verification. In this study, we propose the method to design system with FLC in stability point which is an impotent characteristic of designing system. The circle criterion which is adapted to analysis the nonlinear system is put to use for proposed method. Since SISO FLC has a time-invariant and odd characteristic we can use the critical point not disk which is generally used to determine the stability in the circle criterion, to determine the stability. Using this, we can get the maximum critical point plot of SISO FLC with changing the consequence fuzzy variables. The predetermined critical point plot of FLC can be used to decide the region of the system to be stable. This method is effectively used to design the SISO FLC.

• Journal of Electrical Engineering and Technology
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• v.13 no.5
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• pp.1965-1977
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• 2018

This paper proposed a regenerative braking system (RBS) strategy for battery electric vehicles (BEVs) with a hybrid energy storage system (HESS) driven by a brushless DC (BLDC) motor. In the regenerative braking mode of BEV, the BLDC motor works as a generator. Consequently, the DC-link voltage is boosted and regenerative braking energy is transferred to a battery and/or ultracapacitor (UC) using a suitable switching pattern of the three-phase inverter. The energy stored in the HESS through reverse current flow can be exploited to improve acceleration and maintain the batteries from frequent deep discharging during high power mode. In addition, the artificial neural network (ANN)-based RBS control mechanism was utilized to optimize the switching scheme of the vehicular breaking force distribution. Furthermore, constant torque braking can be regulated using a PI controller. Different simulation and experiments were implemented and carried out to verify the performance of the proposed RBS strategy. The UC/battery RBS also contributed to improved vehicle acceleration and extended range BEVs.

• Journal of Power Electronics
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• v.15 no.1
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• pp.268-277
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• 2015

In this paper, a dual-converter three-phase pulse width modulation (PWM) rectifier based on unbalanced one-cycle control (OCC) strategy is proposed. The proposed rectifier is used to eliminate the second harmonic waves of DC voltage and distortion of line currents under unbalanced input grid voltage conditions. The dual-converter PWM rectifier employs two converters, which are called positive-sequence converter and negative-sequence converter. The unbalanced OCC system compensates feedback currents of positive-sequence converter via grid negative-sequence voltages, as well as compensates feedback currents of negative-sequence converter via grid positive-sequence voltages. The AC currents of positive- and negative-sequence converter are controlled to be symmetrical. Thus, the workload of every switching device of converter is balanced. Only one conventional PI controller is adopted to achieve invariant power control. Then, the parameter tuning is simplified, and the extraction for positive- and negative-sequence currents is not needed anymore. The effectiveness and the viability of the control strategy are demonstrated through detailed experimental verification.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.6
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• pp.89-95
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• 2009

A new class of electronically commutated brushless motor, the flux-switching motor(FSM) is gradually emerging in power tools and household appliances especially fan and pump application because of green policy. This motor offers advantages of high-power density and relatively high efficiency compare with induction motor, low cost and simple motor structure compare with bldc motor. This paper presents the principle of the FSM and design of the 12/6 pole FSM drive system for fan application. Finally, test results of the prototype motor are provided to verify a validity of the fan application with TMS320F2812 DSP and inverter.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.12
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• pp.41-47
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• 2009

In this paper, authors performed improvement of control characteristics of an attraction type magnetic levitation system. The attraction type magnetic levitation system has an inherent instability in the system, therefore its controller must have not only proportional-integral gain but also differential gain additionally. In this paper, authors were proposed control algorithm using disturbance observer(DOB) on feedback signal. The computer simulation and experiments were performed for its verification.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.25-26
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• 2014

배터리를 사용하는 하이브리드 시스템의 확장으로 인하여 2차 전지를 활용할 수 있는 양방향 컨버터의 사용이 증가하고 이에 대한 연구의 필요성 또한 증가하고 있다. 기존 비절연형 단방향 컨버터는 인덕터의 전류와 부하단 캐패시터의 전압을 변수로 지정하고 고정 전원과 고정부하를 대입하여 모델링에 적용했지만, 실제 사용되는 양방향 컨버터의 동작과는 차이가 있다. 또한 이상적인 전원과는 달리 배터리의 단자전압은 SOC 및 충방전 상태에 따라 전압 변동이 일어나고 컨버터의 스위칭 동작에 의해 전압 리플이 발생하기 때문에 제어기를 설계하기 위해서는 이를 반영하여 해석하는 것이 필요하다. 본 논문에서는 비절연형 양방향 컨버터의 양쪽에 부착된 캐패시터가 모두 변수로 적용된 전달함수와 이를 이용하여 설계된 제어기를 제안한다. 컨버터 모델링에 State-Space Averaging 방법을 사용하여 양방향 컨버터의 소신호 분석을 하였고, 충전 모드와 방전 모드 일때 전달함수를 각각 구하였다. 앞서 구한 전달함수를 이용하여 pole/zero 분석을 통해 PI 제어기 설계를 하였고, 주파수 분석을 통해 안정성을 확인하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3647-3653
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• 2012

In active noise control filter, IIR filter structure which used for control filter assures the stability property. The stability characteristics of IIR filter structure is mainly determined by pole location of control filter within unit disc, so stable selection of the value of control filter coefficient is very important. In this paper, we proposed novel adaptive stabilized Filtered_U LMS algorithms with IIR filter structure which has better convergence speed and less computational burden than conventional FIR structures, for multi-channel active noise control with vehicle enclosure signal case. For better convergence speed in adaptive algorithms, fuzzy LMS algorithms where convergence coefficient computed by a fuzzy PI type controller was proposed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.6
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• pp.475-479
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• 2021

There are many difficulties in the applications of smart manufacturing technology in the era of the 4th industrial revolution. In this paper, a test bed was built to aim for acquiring smart manufacturing technology, and the test bed was designed to acquire basic technologies necessary for PLC (Programmable Logic Controller), HMI, Internet of Things (IoT), artificial intelligence (AI) and big data. By building a vehicle maintenance lift that can be easily accessed by the general public, PLC control technology and HMI drawing technology can be acquired, and by using cloud services, workers can respond to emergencies and alarms regardless of time and space. In addition, by managing and monitoring data for smart manufacturing, it is possible to acquire basic technologies necessary for embedded systems, the Internet of Things, artificial intelligence, and big data. It is expected that the improvement of smart manufacturing technology capability according to the results of this study will contribute to the effect of creating added value according to the applications of smart manufacturing technology in the future.

• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.3
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• pp.192-199
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• 2022

In DC distribution systems, a TAB converter employing multiple transformers is one of the most widely used topologies due to its high power density, modularizability, and cost-effectiveness. However, the conventional control technique for a grid-connected mode in the TAB converter cannot maintain its reliability for an islanding mode under a blackout situation. In this paper, the islanding mode control technique is proposed to solve this issue. To verify the relative stability and dynamic characteristics of the control technique, small-signal models of both the grid connected and the islanding mode are derived. Based on the small-signal models, PI controllers are designed to provide suitable power control. The proposed control technique, the accuracy of small-signal models, and the performance of the controllers are verified by simulations and experiments with a 1-kW prototype TAB converter.