• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.3
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• pp.207-214
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• 2019

In this study, discrete-time domain analysis is proposed to investigate the input current of a buck AC/DC light-emitting diode (LED) driver. The buck power factor correction converter can operate in both discontinuous conduction mode (DCM) and continuous conduction mode (CCM). Two discontinuous and two continuous conduction operating modes are possible depending on which event terminates the conduction of the main switch in a switching cycle. All four operating modes are considered in the discrete-time domain analysis. The peak current-mode control with slope compensation is used to design a low-cost AC/DC LED driver. A slope compensation design of the buck AC/DC LED driver is described on the basis of a discrete-time domain analysis. Experimental results are presented to confirm the usefulness of the proposed analysis.

• Journal of Electrical Engineering and Technology
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• v.13 no.5
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• pp.1886-1900
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• 2018

This paper proposes a confronting feedback control structure and controllers for positive output elementary super lift Luo converters (POESLLCs) working in discontinuous conduction mode (DCM). The POESLLC offers the merits like high voltage transfer gain, good efficiency, and minimized coil current and capacitor voltage ripples. The POESLLC working in DCM holds the value of not having right half pole zero (RHPZ) in their control to output transfer function unlike continuous conduction mode (CCM). Also the DCM bestows superlative dynamic response, eliminates the reverse recovery troubles of diode and retains the stability. The proposed control structure involves two controllers respectively to control the voltage (outer) loop and the current (inner) loop to confront the time-varying ON/OFF characteristics of variable structured systems (VSSs) like POESLLC. This study involves two different combination of feedback controllers viz. the proportional integral controller (PIC) plus sliding mode controller (SMC) and the fuzzy logic controller (FLC) plus SMC. The state space averaging modeling of POESLLC in DCM is reviewed first, then design of PIC, FLC and SMC are detailed. The performance of developed controller combinations is studied at different working states of the POESLLC system by MATLAB-Simulink implementation. Further the experimental corroboration is done through implementation of the developed controllers in PIC 16F877A processor. The prototype uses IRF250 MOSFET, IR2110 driver and UF5408 diodes. The results reassured the proficiency of designed FLC plus SMC combination over its counterpart PIC plus SMC.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.129-133
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• 2005

This paper discusses DC/DC converter modeling using average model of switch and critical characterist. Average model of switch approach is expended to the modeling of boundary conduction mode DC/DC converters that operate at the boundary between Continuous Conduction Mode(CCM) and Discontinuous Conduction Mode(DCM). Frequency responses predicted by the average model of switch are verified by simulation and experiment.

• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.173-174
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• 2010

In this paper, authors propose a new buck-boost converter of discontinuous conduction mode (DCM) added electric isolation. The proposed converter with DCM eliminates the complicated circuit control requirement and reduces the size of components. The general converters of high efficiency are made that the power loss of the used switching devices is minimized. To achieve the soft switching operation of the used control switches, the proposed converter uses a lossless snubber capacitor. The proposed converter achieves the soft-switching for all switching devices without increasing their voltage and current stresses. The result is that the switching loss is very low and the efficiency of converter is high. The soft switching operation of the proposed converter is verified by digital simulation and experimental results.

• Journal of information and communication convergence engineering
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• v.18 no.4
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• pp.245-253
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• 2020

The human body and nervous system transmit information through electric charges. After the electric charge transmits information to the brain, we can feel pain, numbness, comfort, and other feelings. Electric therapy is currently used widely in clinical practice because the field of examination is more representative of electrocardiogram, and in the field of treatment is more representative of electrotherapy. In this study, we design a system for neurophysiological therapy and conduct parameter calculation and model selection for the components of the system. The system is based on a discontinuous conduction mode (DCM) boost circuit, and controlled and regulated by a single-chip microcomputer. The system does not only have a low cost but also fully considers the safety of use, convenience of the human-computer interface, adjustment sensitivity, and waveform diversity in the design. In future, it will have strong implications in the field of electrotherapy.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.2
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• pp.52-58
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• 2000

This paper presents a novel power factor corrected(PFC) single-stage AC/DC half-bridge converter, which features discontinuous conduction mode(DCM) and soft-switching. The reduced conduction losses are achieved by the employment of a novel powder factor correction circuitry, instead of the conventional configuration composed of a front-end rectifier followed by a boost converter. To identify the validity of the proposed converter, simulated results of 500[W] converter with 100[V] input voltage and 50[V]output voltage are presented.

• Proceedings of the KIPE Conference
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• 2011.11a
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• pp.169-170
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• 2011

PFC(Power Factor Correction) converters are commonly designed for CCM(Continuous Conduction Mode). However, DCM(Discontinuous Conduction Mode) appears in the input current near the ZCP(Zero Crossing Point) at light loads, resulting in input current distortion. It is caused by inaccurate average current values obtained in DCM. This paper studies a simple digital control scheme that can be operated in both CCM and DCM with minimal changes to the CCM average current control structure.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2115-2117
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• 1998

The output characteristics of solar cell are nonlinear, and these characteristics vary with load solar insolation. solar cell temperature. The PWM power inverter is realized by driving a inverter constructed with a high frequency buck-boost chopper in the discontinuous conduction mode(DCM). This paper present a buck-boost PWM inverter and its application for residential system.

• Journal of Power Electronics
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• v.11 no.6
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• pp.793-800
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• 2011

This paper investigates the operational modes of buck dc-dc converters and their energy transmission methods. The operational modes of such converters are classified in two types, discontinuous conduction mode (DCM) and continuous conduction mode (CCM). In this paper, the critical inductance relation of DCM and CCM is determined. The equations of the output voltage ripple (OVR) for each mode are obtained for a specific input voltage and load resistance range. The maximum output voltage ripple (MOVR) is also obtained for each mode. The filter size is decreased and the minimum required inductance value is calculated to guarantee the minimization of the MOVR. The experimental and simulation results in PSCAD/EMTDC prove the correctness of the presented theoretical concepts.

• Journal of Power Electronics
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• v.15 no.3
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• pp.634-643
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• 2015

This paper presents a high frequency design approach for improving efficiency over a wide load range in the self-driven phase-shifted full-bridge converters for server power systems. In the proposed approach, a detailed ZVS analysis of the lagging leg switches in both the continuous conduction mode (CCM) and the discontinuous conduction mode (DCM) is presented. The optimum dead time and the determination of the appropriate operation mode are given for high efficiency according to the load conditions. Finally, the optimum operation conditions are defined to achieve a high-efficiency. A laboratory prototype operating at 80 kHz, rated 1 kW (12 V-83.3 A), is built to verify proposed theoretical analysis and evaluations. The experimental results show that the maximum efficiency is achieved as 95% and 83.5% at full load and 5% load conditions, respectively.