• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.12
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• pp.5307-5327
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• 2016

Restricted by finite battery energy, traditional wireless sensor networks (WSNs) can only maintain for a limited period of time, resulting in serious performance bottleneck in long-term deployment of WSN. Fortunately, the advancement in the wireless energy transfer technology provides a potential to free WSNs from limited energy supply and remain perpetual operational. A mobile charger called wireless charging vehicle (WCV) is employed to periodically charge each sensor node and keep its energy level above the minimum threshold. Aiming at maximizing the ratio of the WCV's vocation time over the cycle time as well as guaranteeing the perpetual operation of networks, we propose a feasible and optimal solution to this issue within the context of a real-time large-scale deployed WSN. First, we develop two different types of charging cycles: initialization cycles and renewable cycles and give relevant algorithms to construct these two cycles for each sensor node. We then formulate the optimization problem into an optimal construction algorithm and prove its correctness through theoretical analysis. Finally, we conduct extensive simulations to demonstrate the effectiveness of our proposed algorithms.

• Proceedings of the KIPE Conference
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• 2015.11a
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• pp.3-4
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• 2015

본 논문에서는 SP 토폴로지를 가지는 무선전력전송 시스템에서 결합 계수 및 부하 변화에 따른 Zero phase angle (ZPA) 주파수 추종 제어 알고리즘을 제안한다. 제안한 알고리즘은 부가적인 아날로그 회로 없이 기존의 디지털 제어기에 적용되어 ZVS 영역에서 동작하도록 공진 주파수를 추종한다. PSIM 시뮬레이션 및 실험을 통해 주파수 추종 성능을 검증한다.

• Journal of Power Electronics
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• v.17 no.1
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• pp.11-19
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• 2017

This paper proposes a dc/dc converter for electric vehicle onboard chargers using a secondary resonant tank. To attain soft switching characteristics, such as zero voltage switching, magnetizing inductance has been used at the primary side of the transformer. The leakage inductance of the transformer is used as a resonant inductor on the secondary side to avoid the use of a separate inductor as resonance. The proposed converter is applicable for a wide load range. A 6.6KW prototype has been implemented for a wide range of load variations (250V, 330V, 360V, and 413V). A maximum efficiency of 97.4% is achieved at 413V.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.305-306
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• 2013

이 논문은 Single-stage로 구현한 전기 오토바이용 배터리 완속 충전기를 제안한다. 전기 오토바이용 배터리 완속 충전기는 상용전원을 입력으로 사용하므로 $110V_{ac}$ 및 $220V_{ac}$에서 사용이 가능하며 역률 보정이 고려되어야 한다. 일반적으로 역률 개선(Power Factor Correction : PFC)를 담당하는 AC/DC 컨버터와 DC/DC단의 2단 구성의 충전기 구조가 일반적이나, 이를 기존 이단구조의 복잡한 시스템을 단일 전력단으로 설계하였다. 본 논문에서는 전기 오토바이용 2KW급 SRC single-stage 공진형 컨버터를 설계하고 실험 검증하였다.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.2
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• pp.142-151
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• 2020

This paper presents a DC/DC LLC resonant converter with wide input/output voltage gain characteristics and its control method for efficiency improvement. For a wide input/output voltage gain characteristics without designing small transformer magnetization inductance, the proposed converter changes the topology into three modes of operation according to the main switch switching pattern. In each operating mode, variable LINK voltage modulation and frequency modulation were performed to control output voltage and improve operating efficiency. A prototype of a 5-kW DC/DC LLC resonant converter was built and tested to verify the validity and applicability of the proposed converter.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.334-336
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• 2005

This paper proposes a simple MPPT control scheme of a Current- Control-Loop Error system Based that can be obtains a lot of advantage to compare with another digital control method, P&O and IncCond algorithm, that is applied mostly a PV system. An existent method is needed an expensive processor such as DSP that calculated to change the measure power of a using current and voltage sensor at the once. But, a proposed method is easy to solve the cost reduction and power unbalance problems that it is used by control scheme to limit error of a current control of common sensor. This proposed algorithm had verified through a simulation and an experiment on battery charger using PIC that is the microprocessor of a low price.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.295-296
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• 2019

본 논문은 넓은 출력전압 범위와 High Power Density를 위한 절연형 HMF PFC(Isolated Harmonic Modulation PFC)를 제안한다. 제안된 PFC는 변압기 leakage inductance를 회로에 적용시켜 switching device의 voltage stress를 효과적으로 줄일 수 있는 voltage-fed형태의 ful-bridge구조를 기반으로 한다. 출력 측 CV(Constant Voltage) control을 통하여 출력 혹은 link 전압을 load 변동에 상관없이 일정 유지시켜준다. 또한 CC(Constant Current) control 방식을 사용하여 출력 측 battery 특성 조건이 변동되어도 일정하게 충전시켜 줄 수 있도록 한다. HMF 제어방식을 적용한 3.3kW Prototype을 통해 이를 입증한다.

• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.2004-2012
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• 2014

Energy storage devices are necessary to obtain stable utilization of renewable energy sources. When black-out occurs, distributed renewable power sources with energy storage devices can operate under standalone mode as uninterruptable power supply. This paper proposes a dynamic response analysis with small-signal modeling for the standalone operation of a photovoltaic power generation system that includes a bidirectional charger/discharger with a battery. Furthermore, it proposes a DC-link voltage controller design of the entire power conditioning system, using the storage current under standalone operation. The purpose of this controller is to guarantee the stable operation of the renewable source and the storage subsystem, with the power conversion of a very efficient bypass-type PCS. This paper presents the operating principle and design guidelines of the proposed scheme, along with performance analysis and simulation. Finally, a hardware prototype of 1-kW power conditioning system with an energy storage device is implemented, for experimental verification of the proposed converter system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.920-926
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• 2011

In this paper, a solar power emotional LED lightening street lamps with multi control sun tracker is presented. The proposed system has a multiple control sun tracking function and high quality emotional LED lamps. The system is designed to absorb maximum sun lights by temperature sensor and humidity sensor of control circuits. A battery charge-discharge controller is developed for high efficient usage of battery charger for utilization of new and renewal energy. An interface circuit for remote monitoring and controlling is included in the developed system. The proposed multi tracking solar power emotional LED street lamps is better than conventional systems in aspect of tracking operation and energy efficiency, and expected to be a leading model for next generation solar power street lamp system, because it is a new technology combining sun tracking solar power system and emotional lightening system.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.198-200
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• 2018

In this paper a single-stage single-phase differential type isolated AC-DC converter is proposed. This converter eliminates the requirement to use bulky electrolytic capacitor from the system and at the same time provides DC charging by employing the AC Power Decoupling waveform control method. All the switches of the converter achieve ZVS turn on during half line cycle and all diodes achieve ZCS turn off during entire line cycle. A conventional controller is implemented for PFC control and output regulation, whereas a power decoupling controller is added to compensate $2^{nd}$ harmonic ripple power. In addition, an interleaving technique is applied to increase the power range of the converter and reduce the input inductor size. In the end simulation verification is performed and results are obtained for 6.6KW.