• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.14-14
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• 2010

A high voltage current sensing circuit for LED driver IC is designed and verfied by Cadence SPECTRE simulations. The current mirror pair, power and sensing MOSFETs with size ratio of K, is used in our on-chip current sensing circuit. Very low drain voltages of the current mirror pair should be matched to give accurate current sensing, so a folded-cascode opamp with a PMOS input pair is used in our design. A high voltage high side LDMOST switch is used between the current sensing circuit and power MOSFET to protect the current sensing circuit from the high output voltage. Simulation results using 0.35um BCD process show that current sensing is accurate with properly frequency compensated opamp.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1050-1051
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• 2015

In industry, there are several different controllers which can be implemented for power conditioning systems (PCS) such as proportional-resonant (PR), predictive deadbeat (PD), or proportional-integral (PI) controller. But there are not any comparison studies about these controllers. To investigate the differences between the three types of the controllers, this paper presents a comparative study of PR, PI, and PD controllers in a photovoltaic (PV) PCS. These controllers are designed mathematically and simulated for the comparative analysis. The PI controller is designed in the rotating reference (dq) frame. The PR and PD controllers are implemented in the natural (abc) reference frame. The PCS is composed of a DC-DC boost converter and a full bridge inverter. The filter of the PCS is an LCL filter including a passive damping resistor. The parameters of PCS are 3 kW, 25 kHz switching frequency and 220 V-60 Hz grid voltage. The comparison results between these controllers for the grid-connected PCS are clearly shown. The simulation results demonstrate the detailed characteristics of each controller for the PV PCS in order to choose the controller for individual target properly.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.437-442
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• 2001

Recently, transformerless inverters have been studied to reduce sizes and costs of utility-connected PV systems. This paper presents a transformerless PV inverter using a two-phase boost converter of reduced ripples in input current and output voltage, low voltage stress of semiconductor device and reduced size of input reactor. And new PWM method is introduced, whose on-off time is calculated from simultaneous equation induced by fourier series. To verify a validity of the proposed transformerless inverter, computer simulation has been carried out.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.4
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• pp.390-396
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• 2004

Recently, there have been Increasing demands for high power factor and low harmonic distortion in the current drawn from utility. The harmonic limits imposed by international standards. It need the PFC techniques in order to reduce line current harmonics and comply with the standards. The average current control method that is the most proper PFC control method in a switching power supply of middle and high power has been used mostly to PFC control method. However, the switching device of PFC circuit has frequently destructed at power return after instantaneous power interrupt. Therefore, this paper have verified the cause of this problems and proposed the solution through simulation and experiment

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.263-266
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• 2002

In this paper, It is indicating that an issues of the conventional boost converter for high frequency induction heating. To improve those issues, it is proposed, simulated and analyzed that the current resonant circuit, simulated. As the result, we knew that the proposed circuit has a good point to improve the waveform of input current and to make high efficiency. On the other side, in the inverter for the high current power supply, it is proposed that the high frequency inverter of the half bridge topology, be done the circuit analysis to extract the optimal circuit parameter. It is making sure of the soft switching operating by the inductor to reverse parallel connected on the inverter main switch, decreasing the surge voltage when the switch is turn-off by compulsion, and repressing the switch current and bringing the high current amplitude operation by the multi resonance.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.7
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• pp.74-80
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• 2006

This paper describes a solar energy conversion strategy is applied to grid-connected single phase inverter by the maximum power point of conversion strategy. The maximum power point of tracking is controlled output power of PV(photovoltaic)modules, based on generated circuit control MOSFET switch of two boost converter for a connected single phase inverter with four IGBT's switch in full bridge. The generation control circuit allows each photovoltaic module to operate independently at peak capacity, simply by detecting of the output power of PV module. Furthermore, the generation control circuit attenuates low-frequency ripple voltage. which is caused by the full-bridge inverter, across the photovoltaic modules. The effectiveness of the proposed inverter system is confirmed experimentally and by means of simulation.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.4
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• pp.57-66
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• 2012

When typical Z-source DC/AC inverter(ZSI) is operated in high voltage gain area, because of its high duty ratio, voltage and current stress in Z-network of typical ZSI are increased. This paper proposes a new switched trans ZSI(STZSI) with two switched trans cells which consist of one trans and two diodes. To confirm the operation performance of the proposed system, the PSIM simulation is performed for typical ZSI, switched inductor ZSI and the proposed STZSI. Voltage / current stress and transient state characteristics of each method are compared under the condition of DC input voltage 100[V] and output phase voltage 66[Vrms]. As a result, we confirmed that transient state of the proposed STZSI is short compared with the conventional ZSI because the high voltage gain is obtained using the same duty ratio, also a low duty ratio is required for the same output voltage. Finally, we could know the proposed system have low voltage and current stress in Z-network compared with the conventional ZSI.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.4
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• pp.326-333
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• 2011

This paper studies battery charging methods using existing motor inductance and 3-phase inverters without an additional charger to charge the battery of Plug-in Hybrid Electric Vehicles (PHEVs). As inverter switch control and motor coil used as the energy storage device for boosting make the system the boost converter, the additional charger is eliminated and volume, weight, and cost for the charger are reduced. Various charging methods according to topologies of the system and configurations of the controller are analyzed and verified by PSIM simulation.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.132-134
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• 2007

하이브리드 차량 및 전기차량 구동 모터의 권선저항에 의한 손실 및 모터의 크기를 줄이기 위해 고효율, 고승압형 DC-DC 컨버터 사용이 요구된다. 기존의 부스트 컨버터는 기생저항 성분에 의해 고승압이 불가능하여 변압기를 사용하여 승압비를 향상시킨 current-fed push-pull, current-fed full bridge, dual inductor-fed 부스트 컨버터 등으로 변형되어 사용되어 왔다. dual inductor-fed 부스트 컨버터의 경우 동일조건하에서 앞서 기술된 2가지 컨버터보다 2배의 승압비를 얻을 수 있으며 1차측 전류 스트레스가 낮은 장점을 가지고 있어 대전력, 고승압 응용에 적합하다. 하지만 변압기의 누설인덕턴스에 의한 써지성 전류/전압을 제한하기 위한 부가적인 snubber회로의 사용으로 효율을 떨어뜨리게 되는 단점을 가지고 있다. 본 논문에서는 이러한 단점을 보완할 수 있는 새로운 2개의 인덕터와 1개의 변압기를 갖는 DC-DC 컨버터를 제안한다. 제안된 컨버터의 동작원리와 모드해석을 실시하고 최종적으로 400W, 42Vdc (Battery)/400Vdc (Electric Motor) 실험결과를 통해 이를 검증한다.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.182-184
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• 2007

본 논문에서는 2단 AC/DC 컨버터와 단일단 AC/DC 컨버터가 가지고 있는 단점들을 개선 할 수 있는 새로운 준 단일 전력단 컨버터를 제안한다. DC/DC 단으로는 동적 특성이 좋은 LLC 컨버터를 채용하여 별도의 제어기 없이 고정 주파수 및 고정 Duty(50%) 발생기에 의해 Open Loop로 구동 시킴으로써 저가격화 및 고효율화를 획득 할 수 있다. 또한 역률개선단은 Boost 컨버터를 채용하고 간단한 제어기 1개를 사용하여 역률 개선과 동시에 DC/DC 단의 최종출력을 제어한다. 기존 2단 PFC 컨버터와는 다르게 PFC 링크전압을 Feedback 하지 않고 DC/DC 단의 최종 출력을 Feedback 하여 제어한다. 제안된 회로의 우수성 검증을 위해 600W급 시작품을 이용한 실험 결과를 제시한다.