• International Journal of Fuzzy Logic and Intelligent Systems
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• 제10권2호
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• pp.113-118
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• 2010

This paper proposed an ECAM (Electronic cam) control system which has simple and general structure. The proposed cam controller adopted the linear and polynomial curve-fitting method to generates a smooth cam profile curve function. Smooth motion trajectory of master actuator guarantees the good performance of slave motion and has an important effect on the interpolation quality of ECAM. The auto-tuning PID velocity controller was applied to overcome the uncertainties in ECAM, and the gains of the controller are updated continuously to ensure the consistency of system performance under varying working conditions. The robustness of system against the varying load torque disturbances and noises is guaranteed by using the load torque disturbance observer to suppress the disturbance on master actuator. The velocity compensator was applied to compensate the degradation of performance of slave motion caused from the varying driving speed of master motion. The stability and validity of the proposed ECAM control system was verified by simulation results.

• 전기학회논문지
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• 제58권2호
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• pp.232-238
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• 2009

Flicker, also known as voltage fluctuation, is a newest problem of power quality issues, because it is caused by nonlinear loads such as electrical arc furnace and large-scale induction motor, which are country-widely used as the heavy industries of a country develop. An international standard, International Electrotechnical Commission (IEC) 61000-4-15, was published in 1997 and revised in 2003. With increasing concerns about flicker, its mitigation methods have been also studied. General countermeasures for flicker are divided into three categories: a) enhancing the capacity of supplying system, b) Series elements including series reactor and series capacitor and c) power electronic devices including static VAR compensator (SVC) and static synchronous compensator (STATCOM). This paper introduces how to mitigate the voltage flicker at the point of common coupling (PCC) and presents how to simulate and compare the flicker alleviating effects by each mitigation method, using IEC flickermeter based on the Matlab/Simulink program.

• 대한임베디드공학회논문지
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• 제10권5호
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• pp.297-305
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• 2015

AFLS (Adaptive front lighting System) is being applied to improve safety in driving automotive at night. Safe embedded system for controlling head-lamp has to be tightly designed by considering safety requirement of hardware-dependent software, which is embedded in automotive ECU(Electronic Control Unit) hardware under severe environmental noise. In this paper, we propose an adaptive headlight controller with newly-designed symmetric angle sensor compensator, which is integrated with ECU-based adaptive front light system. The proposed system, on which additional backup hardware and emergency control algorithm are integrated, effectively detects abnormal situation and restore safe status of controlling the light-angle in AFLS operations by comparing result in symmetric angle sensor. The controlled angle value is traced into internal memory in runtime and will be continuously compared with the pre-defined lookup table (LUT) with symmetric angle value, which is used in normal operation. The watch-dog concept, which is based on using angle sensor and control-value tracer, enables quick response to restore safe light-controlling state by performing the backup sequence in emergency situation.

• Journal of Power Electronics
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• 제17권3호
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• pp.686-694
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• 2017

Due to the wide use of electronic products, digitally controlled DC-DC converters are attracting more and more attention in recent years. However, digital control strategies may introduce undesirable Limit Cycle Oscillation (LCO) due to quantization effects in the Analog-to-Digital Converter (ADC) and Digital Pulse Width Modulator (DPWM). This results in decreases in the quality of the output voltage and the efficiency of the system. Meanwhile, even if the resolution of the DPWM is finer than that of the ADC, LCO may still exist due to improper parameters of the digital compensator. In order to discover how LCO is generated, the state space averaging model is applied to derive equilibrium equations of a digital PID controlled DC-DC converter in this paper. Furthermore, the influences of the parameters of the digital PID compensator, and the resolutions of the ADC and DPWM on LCO are studied in detail. The amplitude together with the period of LCO as well as the corresponding PID parameters are obtained. Finally, MATLAB/Simulink simulations and FPGA verifications are carried out and no-LCO conditions are obtained.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
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• pp.375-378
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• 2003

This paper presents a study on the power factor improvement of the Wind turbine Generation System(WTGS) at Haeng-won wind farm in Jeju Island. Vestas WTGS named V47 as a model system is selected in this paper, and has 660 kW Power ratings. In this system, power factor correction is controlled by the conventional method with power condenor bank. So, model system at Haeng-won wind farm has very low power factor in the area of low wind speed, which is from 4 m/s to 6 m/s. This is caused by the power factor correction using power condenser bank To improve the power factor in the area of low wind speed, we used the static var compensator(SVC) using current controlled PWM power converter by IGBT switching device. finally, to verify the profosed method, the results of computer simulation using Psim program are presented to support the discussion.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 춘계종합학술대회
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• pp.423-426
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• 2001

본 논문에서는 전압 안정화 특성을 갖는 전자식 강압형 변압기가 제안된다. 제안된 전자식 변압기는 다음과 같은 특징을 갖는다. 1) 무게가 1kW 기준 일반 변압기의 40% 수준이다. 2) PWM 제어에 의하여 입력전압의 변동에 무관한 출력전압을 유지하는 전압 안정화 기능을 갖는다. 3) 전원 또는 부하단의 Emergency에 대하여 회로 차단기의 기능도 갖는다 4) 부하에 최기 전원 공급시, 낮은 전압으로부터 점진적으로 증가시켜가면서 전원을 인가하여, 전원 투입시 발생한 수 있는 돌입전류나 과도 충격을 제거할 수 있다. 그 밖에 무부하시 전원차단 기능과, 왜곡된 입력전압에 대한 보상기능을 추가 할 수 있다. 본 논문에서는 제안된 강압형 전자식 변압기의 회로 구성과 특징을 설명하고, 이를 PSPICE 시뮬레이션을 통하여 동작특성을 보인다.

• 한국정보통신학회논문지
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• 제5권2호
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• pp.309-313
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• 2001

본 논문에서는 Custom Power 응용을 위한 전압 안정화 특성을 갖는 다기능 3상 전자식 강압형 변압기가 제안된다. 제안된 전자식 변압기는 다음과 같은 특징을 갖는다. 1) 무게가 1㎾ 기준 일반 변압기의 40% 수준이다. 2) PWM 제어에 의하여 입력전압의 변동에 무관한 출력전압을 유지하는 전압 안정화 기능을 갖는다 3) 전원 또는 부하단의 Emergency에 대하여 회로 차단기의 기능도 갖는다. 4) 부하에 최초 전원 공급시, 낮은 전압으로부터 점진적으로 증가시켜가면서 전원을 인가하여, 전원 투입시 발생할 수 있는 돌입전류나 과도 충격을 제거할 수 있다. 그 밖에 무부하시 전원차단 기능과, 왜곡된 입력전압에 대한 보상기능을 추가 할 수 있다. 본 논문에서는 제안된 강압형 전자식 변압기의 회로 구성과 특징을 설명하고, 이를 PSPICE 시뮬레이션을 통하여 동작특성을 보인다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.462-467
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• 2003

As for control systems, many researchers give optimal structures of the finite-word-length compensator. D. Williamson solved a fixed-point case against colored noise for the LQG problem. Recently, one of the authors derived an optimal filter against colored noise. And consequently, we apply the result to a twodegree-of-freedom control system in this paper. In addition the perturbation of the coefficients is considered. Furthermore, simulation results indicate this method gives better than other structures.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 B
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• pp.472-474
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• 1999

The design procedure originally proposed by Manabe is involved, because experiences and manual skills are necessary, especially, in the case of designing low fixed-order controllers for high-order plants, and the concept of manual skills are not clearly defined. So we propose a concept and a design procedure of Approximate Pole Placement that substitute for the manual skills. And the validity of the procedure is shown by example problems. Moreover, we also propose a procedure of adding the role of improving transient response performance to the feedforward compensator that previously has only the role of tracking in steady-state the validity of the procedure is also shown by example problems.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 기술교육위원회 창립총회 및 학술대회 의료기기전시회
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• pp.19-22
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• 2001

For stabilization and improving power factor in the power lines, various Static Var Compensators(SVC) have been considered to be installed and partly applicated already. With all these merits of the SVC, it stil has demerits, principally evoking harmonic problems. So far, many harmonic reduction type inverters have been used in various parts. In this paper, the reactive power is controlled by amplitude of the output voltage. This paper propose that the multiple voltage source inverter have controllable power factor made by load vary at receive-stage as lagging and leakage control. The theoretical analysis on this system was confirmed through the computer simulation and the experiments.