• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.1
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• pp.63-73
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• 2022

The differential power processor (DPP) system is used to prevent a decrease in the total power generation due to the partial shading of photovoltaic modules. Compared with traditional series strings and full power processing (FPP) converter solutions, the DPP converter system shows advantages in terms of modularization process, volume, and transformation losses. However, the system has a limitation in that the power generation process of differential power processors produces lower power under certain irradiation conditions. This paper proposes a structure and operating algorithm for differential power processing modules that can use a single power converter for multiple strings. The operational algorithm for the differential power regulators allows the maximum power generation to be maintained in comparison with conventional series-connected and differential power processing methods even under various partial shading conditions. The operation algorithm of the proposed DPP is verified by Matlab/Simulink simulations.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.4
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• pp.109-115
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• 2010

Differential Power Analysis (DPA) is well known as one of efficient physical side-channel attack methods using leakage power consumption traces. However, since the power traces usually include the components irrelevant to the encryption, the efficiency of the DPA attack may be degraded. To enhance the performance of DPA, we introduce a pre-processing technique which extracts the encryption-related parts from the measured power consumption signals. Experimental results show that the DPA attack with the use of the proposed pre-processing method detects correct cipher keys with much smaller number of signals compared to that of the conventional DPA attack.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.175-176
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• 2016

기존의 태양광 시스템은 대체로 고정된 형태로 사용되었지만 태양광 시스템의 응용분야가 확장됨에 따라 전기자동차, 웨어러블 기기 등의 이동식 태양광 시스템 또한 많이 개발되고 있다. 이동식 태양광 시스템의 경우 불균일한 태양빛에 많이 노출되며, 이러한 불균일한 태양빛은 극심한 시스템 효율 저하를 야기한다. 본 연구에서는 이러한 시스템 효율 저하 문제를 해결하기 위해 differential power processing (DPP) 컨버터를 병렬로 적용한 photovoltaic (PV) 충전 가방을 제시하였다. DPP 컨버터는 PV 충전 가방이 불균일한 태양빛에 노출되어도, 각각의 태양전지가 고유의 최대 전력점에서 작동하도록 제어하는 역할을 한다. PV 충전 가방은 4개의 태양전지로 구성되어 있으며 충분한 태양빛 아래, 5 W의 출력전력을 가질 수 있다. PV 충전 가방은 하나의 front-end 컨버터와 4개의 DPP 컨버로 구성되었으며, P-SIM 시뮬레이션과 실험을 통해 front-end 컨버터와 DPP 컨버터의 정상 작동을 입증하였다. 또한 동일한 태양빛에 노출된 경우, 기존의 연결 방법 중 하나인 병렬 배열은 1.49 W의 출력 전력을 가진 반면, DPP 시스템은 4.35 W의 출력 전력을 가져 약 3배 높은 출력 전력을 확인하였다.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.48-49
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• 2017

태양광 발전 시스템 구현에 있어 가장 큰 문제점 중 하나는 불균일한 태양빛 조건에서의 전체 시스템 발전량 감소이다. 이를 해결하기 위해 module-integrated converter (MIC), dc optimizer, differential power processing (DPP) 등 다양한 컨버터가 연구되고 있다. 그 중에서도 DPP 컨버터는 낮은 전력변환 손실로 높은 시스템 효율을 얻을 수 있어 최근 많은 주목을 받고 있다. 보통 그리드 연결형 태양광발전 시스템에 적용되는 직렬 DPP의 경우, 이미 많은 연구가 진행되고 있지만, 병렬 DPP의 경우 아직 많은 연구가 필요한 상황이다. 본 논문에서는 front-end 컨버터의 존재 유무에 따른 두 가지 병렬 DPP 컨버터 배열을 비교 분석 하였다. Front-end 컨버터가 적용된 병렬 DPP 컨버터 배열의 경우, dc 전압과 태양전지의 전압 차이를 최소화해 전력 변환 손실을 감소시킬 수 있지만, front-end 컨버터에서 추가적인 전력 변환 손실이 발생한다. Front-end 컨버터가 없는 경우, dc 전압과 태양전지의 전압차이가 커 DPP 컨버터에서 발생하는 전력 변환 손실이 커진다. 따라서 주어진 조건 아래 효율적인 병렬 DPP 컨버터 디자인을 위한 가이드라인을 본 논문에서 제시하고자 한다.

• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.5
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• pp.379-387
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• 2019

A bidirectional flyback converter is a suitable topology for use in a PV-to-bus differential power processing (DPP) module for PV applications due to its electrical isolation capability, bidirectional power transfer, high step-up ratio, and simple circuit structure. However, the bidirectional flyback converter design should consider the effect of the output-side power switch utilized for bidirectional operation compared with that of the conventional flyback converter. This study presents the structure and design methodology of the bidirectional flyback converter for a PV DPP module. Magnetizing inductance is designed by calculating the power loss of converter components within the rated load range under the discontinuous conduction mode, which is unaffected by the reverse recovery characteristics of the anti-parallel diode of the output-side power switch. The validity of the proposed design methodology is verified using a 25 W bidirectional flyback converter prototype. The operational principles and the performance of the DPP operation are verified using practical DPP modules consisting of bidirectional flyback converters implemented according to the proposed design methodology.

• Journal of Power Electronics
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• v.16 no.5
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• pp.1629-1638
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• 2016

Differential power processing (DPP) systems are among the most effective architectures for photovoltaic (PV) power systems because they are highly efficient as a result of their distributed local maximum power point tracking ability, which allows the fractional processing of the total generated power. However, DPP systems require a high-efficiency, high step-up/down bidirectional converter with broad operating ranges and galvanic isolation. This study proposes a single, magnetic, high-efficiency, high step-up/down bidirectional DC-DC converter. The proposed converter is composed of a bidirectional flyback and a bidirectional isolated switched-capacitor cell, which are competitively cheap. The output terminals of the flyback converter and switched-capacitor cell are connected in series to obtain the voltage step-up. In the reverse power flow, the converter reciprocally operates with high efficiency across a broad operating range because it uses hard switching instead of soft switching. The proposed topology achieves a genuine on-off interleaved energy transfer at the transformer core and windings, thus providing an excellent utilization ratio. The dynamic characteristics of the converter are analyzed for the controller design. Finally, a 240 W hardware prototype is constructed to demonstrate the operation of the bidirectional converter under a current feedback control loop. To improve the efficiency of a PV system, the maximum power point tracking method is applied to the proposed converter.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.67 no.3
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• pp.137-142
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• 2018

Energy harvesting technology is drawing attention as a means of collecting various eco-friendly energy and accumulating residual energy. Recently, differential power processing (DPP) is being developed as part of energy harvesting. This is being studied as a solution to the loss of power generation between power modules and the problems caused by module small losses depending on the size of power production. In this paper, we propose the necessity of the DPP by comparing and analyzing energy harvesting related module integration system and power supply efficiency of DPP. The power efficiency of the converter and the power difference between the wind power and the photovoltaic power supply have been changed to demonstrate the effectiveness of the proposed system.

• The KIPS Transactions:PartC
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• v.18C no.4
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• pp.213-216
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• 2011

Differential Power Analysis is fully affected by various noises including temporal misalignment. Recently, Ryoo et al have introduced an efficient preprocessor method leading to improvements in DPA by removing the noise signals. This paper experimentally proves that the existing preprocessor method is not applied to all processor. To overcome this defect, we propose a Differential Trace Model(DTM). Also, we theoretically prove and experimentally confirm that the proposed DTM suites DPA.

• Journal of Power Electronics
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• v.17 no.4
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• pp.1037-1047
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• 2017

The Differential Power Processing (DPP) converter is a promising multi-module photovoltaic inverter architecture recently proposed for photovoltaic systems. In this paper, a DPP converter architecture, in which each PV-panel has its own DPP converter in shunt, performs distributed maximum power point tracking (DMPPT) control. It maintains a high energy conversion efficiency, even under partial shading conditions. The system architecture only deals with the power differences among the PV panels, which reduces the power capacity of the converters. Therefore, the DPP systems can easily overcome the conventional disadvantages of PCS such as centralized, string, and module integrated converter (MIC) topologies. Among the various types of the DPP systems, the feed-forward method has been selected for both its voltage balancing and power transfer to a modified H-bridge inverter that needs charge balancing of the input capacitors. The modified H-bridge multi-level inverter had some advantages such as a low part count and cost competitiveness when compared to conventional multi-level inverters. Therefore, it is frequently used in photovoltaic (PV) power conditioning system (PCS). However, its simplified switching network draws input current asymmetrically. Therefore, input capacitors in series suffer from a problem due to a charge imbalance. This paper validates the operating principle and feasibility of the proposed topology through the simulation and experimental results. They show that the input-capacitor voltages maintain the voltage balance with the PV MPPT control operating with a 140-W hardware prototype.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.967-970
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• 1999

A novel linear transconductor for low-voltage low-power signal processing is proposed. The transconductor consists of a pnp differential-pair and a npn differential-pair which are biased by local negative feedback. The simulation results show that the transcondcutor with transconductance of 50 $mutextrm{s}$ has a linearity error of 0.05% and the power dissipation is 2.44 ㎽ over an input linear range from -2V to +2V at supply voltage $\pm$3V.