• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2004년도 ICCAS
• /
• pp.1975-1980
• /
• 2004

A parallel active power filter is designed and implemented to compensate for undesired current harmonics generated by a nonlinear load. The filter works based on PWM strategy and control signal is generated using a model predictive controller. To evaluate the achievements, a PI controller is also designed and implemented. Experimental results indicate about 50% increase in the efficiency over PI controller.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 하계학술대회 논문집 B
• /
• pp.1072-1074
• /
• 2003

In this paper, a new control strategy of a series active power filter using direct compensating voltage extraction method is proposed. This control algorithm compensates harmonics, reactive power and neutral line currents which are generated by balanced or unbalanced nonlinear loads. The advantage of this method is that the compensating voltage of the series active power filter can be extracted without phase transformation. Therefore, calculation time is shorten and the control method is simple compared with conventional method as the p-q theory In addition, this control strategy was applied for the series active power filter in 3-phase 4-wire system which is widely employed in distributing electric energy to several office building and manufacturing plants. Some results obtained from the experimental model using the proposed method are presented to demonstrate and confirm its validity.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2013년도 전력전자학술대회 논문집
• /
• pp.246-247
• /
• 2013

This paper investigates control algorithms for a doubly fed induction generator with a back-to-back three-level neutral-point clamped voltage source converter in medium voltage wind power system under unbalanced grid conditions. Control algorithms to compensate for unbalanced conditions have been investigated with respect to four performance factors; fault ride-through capability, instantaneous active power pulsation, harmonic distortions, and torque pulsation. The control algorithm having zero amplitude of torque ripple shows the most cost-effective performance concerning torque pulsation. The least active power pulsation is produced by control algorithm that nullifies the oscillating component of the instantaneous stator active and reactive power. Combination of these two control algorithms depending on the operating requirements and depth of grid unbalance presents most optimized performance factors under the generalized unbalanced operating conditions leading to high performance DFIG wind turbine system. The proposed control algorithms are verified through transient response in the simulation.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2000년도 추계학술대회논문집
• /
• pp.282-286
• /
• 2000

In this paper, magneto-rheological(MR) damper is studied for vibration control of large infra structures under earthquake. Generally, active control devices need a large control force and a high power supply system to reduce the vibration effectively. Large and miss tuned control force may induce the dangerous situation such that the generated large control force acts to amplify the structural vibration. Recently, to overcome the weaknesses of the active control, the semi-active control method is suggested by many researchers. Semi-active control uses the passive control device of which the characteristics can be modified. Control force of the semi-active device is not generated from the actuator with power supply. It is generated as a dynamic reaction force of the device same as in the passive control case, so the control system is inherently stable and robust. Unlike the case of passive control, control force of semi-active control is adjusted depending on the measured response of the structure, so the vibration can be reduced more effectively against various unknown environmental loads. Magneto-rheological(MR) damper is one of the semi-active devices. Dynamic characteristics of the MR material can be changed by applying the magnetic fields. So the control of MR damper needs only small power. Response time of MR to the input voltage is very short, so the high performance control is possible. MR damper has a high force capacity so it is adequate to the vibration control of large infra structure. Because MR damper has a nonlinear property, normal control method used in active control may not be effective. Clipped optimal control, modified bang-bang control etc. have been suggested to MR damper by many researchers. In this study, sliding mode fuzzy control(SMFC) is applied to MR damper. Genetic algorithm is used for the controller tuning. To verify the applicability of MR damper and suggested algorithm, numerical simulation on the aseismic control is carried out. Simulation model is three-story building structure, which was used in the paper of Dyke, et al. The control performance is compared with clipped optimal control. The present results indicate that the SMFC algorithm can reduce the earthquake-induced vibration very effectively.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
• /
• pp.1360-1363
• /
• 1997

Development and realizatioin of adaptive Active Noise Cntrol used for quieting transformer nosie are planed to provide workers with comfortable working environment and to attenuate the noise for residents in many noisy areas(power plant, power transformer, GIS transformer etc.).

• 전력전자학회논문지
• /
• 제5권4호
• /
• pp.335-342
• /
• 2000

단상 능동전력필터에 있어서 비선형 부하전류를 직접 검출하지 않고 능통전력필터의 직류측 커패시터 전압을 이용해 추정하여 제어하는 방법을 제안한다. 이는 부하전류와 능동전택필터의 직류측 커패시터 전압을 봉사에 검출하는 기존의 방식에 비해 부하전류 검출단을 제거할 수 있음으로써 설치가 간편할 뿐만 아니라 가격을 낮출 수 있으면서도 동일한 성능의 능동전력필터의 구현을 가능하게 한다. 또한 직류측 커패시터 전압제어를 위해 샘플-흘드와 비례제어빙식을 사용하므로 기존의 저역통괴필터와 PI 제어시 적분기로 인한 지연을 없앨 수 있어 빠르고 우수한 과도응답특성을 나타낸다. 전원전압과 보상전류, 스위치 상태에 따라 8개의 모드로 나누어 능동전력필터의 동작을 설명하였으며, 제안한 방법의 성능을 실험을 통해 확인하였다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 하계학술대회 논문집 B
• /
• pp.1096-1098
• /
• 2003

In this paper, the control algorithm and control methods for a combined system of shunt passive filter and series active filter in 3-phase 4-wire system are discussed. Moreover, the 3-phase 4-wire system is widely employed in distributing electric energy to several office building and manufacturing plants. In such systems, the third harmonic and odd multiples of $3^{rd}$($9^{th}$, $15^{th}$, etc.) are termed as triple and zero sequence components that do not cancel each other in the system neutral. As a result, the triple harmonics add together creating a primary source of excessive neutral current. Regarding this concern, this paper presents a new control scheme for a series hybrid active system. This series active power filter acts not only as a harmonic compensator but also as a harmonic isolator. Hence the required rating of the series active filter is much smaller than that of a conventional shunt active filter. However, the performance of the combined system is greatly influenced by the filtering algorithm employed in the active power filter. This paper proposes a series active power filter scheme based on performance function. Some experiments was executed and experimental results from a prototype active power filter confirm the suitability of the proposed approach.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
• /
• pp.373-377
• /
• 1996

Recently, active power factor control for AC/DC converter has been required to replace for a conventional diode rectifier. A voltage type AC/DC converter is widely used to obtain higher regulated DC voltage than input voltage with a unity power factor and a sinusoidal line current. This paper describes several active power factor control method for AC/DC converter. The analysis of several active power factor control is given. The simulations for hysteresis control, peak current control. constant frequency control and average current mode control are represented and compared.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2000년도 전력전자학술대회 논문집
• /
• pp.752-755
• /
• 2000

This paper describes a new algorithm for active power filters which can be control source current symmetrically under unbalanced condition in power system. Positive sequency voltage is detected by symmetrical coordinate method and compensating reference current of active power filters is calculated using by accurate phase angle information of positive sequency voltage. The basic principle of the proposed method is described in detail and the conventional and proposed phase detecting methods are compared and discussed through the simulation results.

• Journal of Power Electronics
• /
• 제11권6호
• /
• pp.931-937
• /
• 2011

This paper presents a method for the performance improvement of a shunt active power filter (SAPF) using the indirect current control (ICC) scheme. Compared to the conventional direct current control (DCC) scheme, the ICC gives better performance with a lower number of sensors. A simplified and efficient control algorithm using a low cost Intel 80C196KC microcontroller is implemented using only two current sensors for the source current and one voltage sensor for the DC-link voltage of the SAPF circuit. The objective is to eliminate harmonics and to compensate the reactive power produced by non-linear loads such as an uncontrolled rectifier feeding an inductive load. The APF is realized using a three phase voltage source inverter (VSI) with a dc bus capacitor. Experimental results are presented to prove the better performance of the ICC method over the DCC one.