• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2007년도 추계학술대회 논문집
• /
• pp.131-133
• /
• 2007

In a design of DC ballast for fluorescent lamp, pre-stage of DC-DC converter is required to keep the constant output lumen performance regardless of variable DC input voltage. In this paper, flyback topology is used for optimum performance of 32W lamp, and various important design points for successful operation over the whole operating range are described.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2009년도 하계학술대회 논문집
• /
• pp.439-439
• /
• 2009

Nowadays, source of MEMS, USN, Hybrid parts pay attention to energy harvesting. On this paper, energy harvesting was studied using piezoelectric effect. And, piezoelectric generator was designed and fabricated. Generators were designed by FEM simulation program and generators were made by attaching cymbal type metal plates on upper and bottom sides of a disc type piezoelectric ceramic. Output AC power was rectified to DC power by full bridge circuit and converted to regular voltage power by DC-DC converter. The final output power was charged to Ni-Cd battery. Using fabricated generators, output voltages dependant on thickness of ceramic, displacement of vibration, frequency of vibration were measured.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1991년도 하계학술대회 논문집
• /
• pp.516-520
• /
• 1991

This paper presents a comparative analysis of two inverter power supply topologies for induction heating and melting applications. The comparison is based on criteria such as resonant condition, component ratings, minimum and maximum operating frequencies, operation under varying load conditions, inverter starting current, and diode reverse recovery time. The voltage source series/parallel resonant inverters are found to offer the best overall performance with respect to converter utilization.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1991년도 하계학술대회 논문집
• /
• pp.500-503
• /
• 1991

Fuel cells power generating system converts the chemical energy of a fuel directly into electrical energy. The merits of fuel cells power generating system are pollution free and high energy conversion efficiency. Fuel cells power generating system includes the DC/AC converter. DC source obtained from stack is converted to the constant AC voltage or current by the inverter. In this paper, the power control techniques for the fuel cells power generating system are described.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2008년도 추계학술대회 논문집 전력기술부문
• /
• pp.62-64
• /
• 2008

본 연구에서는 펄스다중화 보조회로론 이용한 18-step Back-to-Back 전압원 컨버터를 제안한다. 제안하는 Back--Back 전압원 컨버터는 교류연계점에서 유 무효전력의 독립적인 제어가 가능하다. 펄스수를 증가시키는 방법은 이론적인 접근을 통해 분석하였으며, 제안하는 시스템의 동작은 PSCAD/EMTDC 소프트웨어로 시뮬레이션 모델을 개발하여 확인하였고 실질적인 성능검증은 하드웨어 축소모형을 제작하고 실험을 통해 실시 하였다.

• Journal of Power Electronics
• /
• 제16권4호
• /
• pp.1612-1620
• /
• 2016

This paper presents the dynamic excitation control of a siphon-turbine coupled pico-hydro powered cage rotor induction generator and load matching for off-grid electricity generation. Through the proposed dual-role of the current-controlled voltage source converter (VSC), acting as static synchronous compensator and load controller, real and reactive power are dynamically controlled in a decoupled manner with a self supported DC-bus. The proposed scheme entails minimal computation for ensuring the rated (set) capacity of real power. The scheme also exhibits fault immunity for protection, thus enabling the effective handling of constant power electrical loads presented by base telecom station towers in remote locations. The performance of the system is evaluated under MATLAB/Simulink and is experimented through a developed hardware prototype. Simulation and experimental results show close conformity and validate the effectiveness of the proposed scheme.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2009년도 정기총회 및 추계학술대회 논문집
• /
• pp.228-230
• /
• 2009

본 논문에서는 전류형 인버터(CSI)와 전압형 인버터(VSI)를 조합하여 유도성 부하에 정현파 전류를 공급하는 시스템에서, LC 소자를 추가함으로써 전압형 인버터의 VA rating을 줄일 수 있는 방법을 제안하였다. 전력제어용 스위칭 소자인 SCR은 대용량인 장점이 있는 반면에 턴오프 제어가 되지 않고, 비선형 특성으로 인해 고조파가 발생한다. 이러한 단점을 개선하기 위해 전압형 인버터를 사용하여, SCR를 OFF하고 부하에 정현파 전압/전류를 제공한다. 또한, 출력단에 수동 LC 필터를 추가하여 전압원 인버터의 VA rating을 저감시키는 구조를 연구하고 이를 Psim을 이용한 시뮬레이션을 통해 검증하였다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1992년도 하계학술대회 논문집 B
• /
• pp.1074-1076
• /
• 1992

By using nonlinear loads in power line, reactive power and harmonics are occured. In this thesis, on the basis of the instantaneous reactive power theory, the calculation method of compensation current commands and the current control characteristics of active power filter using voltage source PWM converter are presented. The calculation of compensation current is performed by DSP within 50 usec. And the Pl control of current is performed by analog devices. The compensations of harmonic current in rectifier loads and unbalance currents are proved by experiments.

• Journal of Mechanical Science and Technology
• /
• 제18권4호
• /
• pp.592-596
• /
• 2004

Corrosion is never avoided in the use of materials with various environments. The underwater hull is normally protected against rusting by several coatings of anti-corrosive paint. The purpose of ICCP(Impressed Current Cathodic protection) system is to eliminate the rusting or corrosion, which occurs on metal immersed in seawater. The anode of ICCP system is controlled by an external DC source with converter. The function of anode is to conduct the protective current into seawater. The proposed algorithm includes the harmonic suppression control strategy and the optimum protection strategy and has tried to test the requirement current density for protection, the influence of voltage, the protection potential. This paper was studied the variation of potential and current density with environment factors, time and velocity, and the experimental results will be explained.

• Journal of Power Electronics
• /
• 제14권6호
• /
• pp.1272-1280
• /
• 2014

This paper presents solutions for fault detection and diagnosis of two-level, three phase voltage-source inverter (VSI) topologies with IGBT devices. The proposed solutions combine redundant standby VSI structures and contactors (or relays) to improve the fault-tolerant capabilities of power electronics in applications with safety requirements. The suitable combination of these elements gives the inverter the ability to maintain energy processing in the occurrence of several failure modes, including short-circuit in IGBT devices, thus extending its reliability and availability. A survey of previously developed fault-tolerant VSI structures and several aspects of failure modes, detection and isolation mechanisms within VSI is first discussed. Hardware solutions for the protection of power semiconductors with fault detection and diagnosis mechanisms are then proposed to provide conditions to isolate and replace damaged power devices (or branches) in real time. Experimental results from a prototype are included to validate the proposed solutions.