• Journal of Power Electronics
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• 제7권3호
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• pp.265-270
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• 2007

Equal rating DC-DC converter modules can be connected in series at the input for circuits requiring higher input voltages and in parallel at the output for circuits requiring higher output currents. Since the converter modules may not be practically identical, closed loop control has to ensure that each module equally shares the total input voltage and the load current. A control scheme consisting of a common output voltage loop, individual inner current loops and individual input voltage loops have been designed in this work to achieve input voltage and load current sharing as well as load voltage regulation under supply and load disturbances. The output voltage loop provides the basic reference for the inner current loops, which are also modified by the respective input voltage loops. The average of the converter input voltages, which is dynamically varying, is chosen as the reference for input voltage loops. This choice of reference eliminates interaction among different control loops. Type II compensators and Fuzzy Logic Controllers (FLCs) are designed and compared through MATLAB based simulation and FLC is found to be satisfactory. Hence TMS320F2407A DSP based FLC is implemented and the results are presented which prove the superiority of the FLC developed for this research.

• 전기학회논문지
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• 제59권11호
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• pp.1996-2005
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• 2010

This paper proposes a new method for constant control of the output AC voltage of a voltage-fed three phase Z-source inverter (ZSI), in case of Z-network DC voltage variation or heavy change of load. The modulation index for the reference output AC voltage of ZSI can be calculated by the basic definition of ZSI, the input DC voltage and capacitor voltage of Z-network. And, the output AC voltage of ZSI is controlled by the modified space vector modulation (SVM) with the calculated modulation index. By the proposed method, the modulation index of output AC voltage is closely following in the reference modulation index. The validity of the proposed method is verified using PSIM simulation. In case which the input DC voltage of ZSI is heavily changed from 100[V] to 70[V] (or to 150[V]) and in case which load is changed from $30[\Omega]$ to $10[\Omega]$, we confirmed that the output AC voltage of ZSI is constantly controlled by the proposed method because the modulation index of ZSI is also simultaneously changed. Finally, FFT and %THD of the output voltage and current of ZSI by the proposed method are analyzed.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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• pp.255-258
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• 1996

This paper describes a DC voltage controller for the DC power supply which is constructed using the full-bridged MOS-FET DC-to-RF power inverter and rectifier. The full-bridged MOS-FET DC-to-RF inverter consisting of four MOSFET arrays and an output power transformer has a control function which is able to control the RF output power when the widths of the pulse voltages which are fed to four MOS-FET arrays of the fall-bridged inverter are changed using the pulse width control circuit. The power conversion efficiency of the full-bridged MOS-FET DC-to-RF power inverter was approximately 85 % when the duty cycles of the pulse voltages were changed from 30 % to 50 %. The RF output voltage from the full-bridged MOS-FET DC-to-RF inverter is fed to the rectifier circuit through the output transformer. The rectifier circuit consists of GaAs schottky diodes and filters, each of which is made of a coil and capacitors. The power conversion efficiency of the rectifier circuit was over 80 % when the duty cycles of the pulse voltages were changed from 30 % to 50 %. The output voltage of the rectifier circuit was changed from 34.7V to 37.6 V when the duty cycles of the pulse voltages were changed from 30 % to 50 %.

• 제어로봇시스템학회논문지
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• 제18권4호
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• pp.371-374
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• 2012

DC/DC switching power converters produce DC output voltages from different stable DC input sources regulated by a bi-polar transistor. The converters can be used in regenerative braking of DC motors to return energy back in the supply, resulting in energy savings for the systems containing frequent stops. The voltage mode DC/DC converter is composed of a PWM (Pulse Width Modulation) controller, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), an inductor, and capacitors, etc. PWM is applied to control and regulate the total output voltage. It is shown that the output of DC/DC converter depends on the variation of threshold voltage at MOSFET and the variation of pulse width. In the PWM operation, the missing pulses, the changes in pulse width, and a change in the period of the output waveform are studied by SPICE (Simulation Program with Integrated Circuit Emphasis) and experiments.

• 조명전기설비학회논문지
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• 제17권2호
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• pp.58-65
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• 2003

일반적인 단상 PFC 컨버터는 직류전압을 일정한 기준값으로 제어할 수 있으나 시스템의 구성상 직류전압과 교류전압 및 전류등을 검출하여 제어하기 때문에 전체적으로 제어 시스템이 복잡하고, 가격이 비싸며, 신속성등의 문제점들이 대두되어지고 있다. 이러한 문제점들을 해결하기 위하여 본 논문에서는 센서리스 PFC 컨버터 회로를 제안하여 교류 전압파형 검출만으로 전체 시스템을 간단하게 제어하였다. 그리고 초퍼회로에서 제어된 전압량 Kd(Ed/Ea)에 의해서 직류출력전압을 직접적으로 제어하였으며, 직류출력전압의 변동율이 회로의 파라미터에 따른 변화의 특징에 대해서 서술하였다. 이러한 모든 사항아느 실험을 통하여 타당성을 증명하였다.

• Journal of Power Electronics
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• 제10권3호
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• pp.245-250
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• 2010

Input-series-output-parallel (ISOP) converters consisting of multiple modular DC/DC converters can enable low voltage rating switches to be used under high voltage input applications. This paper presents a digital control strategy, which can achieve equal sharing of input voltage for a modular ISOP system consisting of two-transistor forward DC/DC converters by forcing the input voltages of neighboring modules to be equal. The proposed scheme is analyzed using small signals analysis based on the state space average method. The performance of the proposed control strategy is verified with an experimental prototype of an ISOP converter made up of three two-switch forward converters.

• 공학기술논문지
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• 제5권4호
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• pp.349-353
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• 2012

Recently, Mobile multimedia equipments as smart phone and tablet pc requirement is increasing and this market is also being expanded. These mobile equipments require large multi-media function, so more power consumption is required. For these reasons, the needs of power management IC as switching type dc-dc converter and linear regulator have increased. DC-DC buck converter become more important in power management IC because the operating voltage of VLSI system is very low comparing to lithium-ion battery voltage. There are many people to be concerned about digital DC-DC converter without using external passive device recently. Digital controlled DC-DC converter is essential in mobile application to various external circumstance. This paper proposes the DC-DC Buck Converter using the AVR RISC 8-bit micro-processor control. The designed converter receives the input DC 18-30 [V] and the output voltage of DC-DC Converter changes by the feedback circuit using the A/D conversion function. Duty ratio is adjusted to maintain a constant output voltage 12 [V]. Proposed converter using the micro-processor control was compared to a typical boost converter. As a result, the current loss in the proposed converter was reduced about 10.7%. Input voltage and output voltage can be displayed on the LCD display to see the status of the operation.

• 전기학회논문지
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• 제58권7호
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• pp.1405-1410
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• 2009

Output voltage of a DC/DC power converter system is likely to be distorted if variable loads exist in the output terminal. This paper presents a new disturbance observer(DOB) approach to maintain a robust regulation of the output voltage of a boost type DC/DC converter. Unlike the buck-type converter case, the regulation problem of the boost converter is very complicated by the fact that, with respect to the output voltage to be regulated, the system is non-minimum phase. Owing to the non-minimum phase property the classical DOB approach has not been applied to the boost converter. Motivated by a recent result on the application of DOB to non-mimimum phase system, an output feedback control law is proposed by using a parallel feedforward compensator. Simulation results using the Simulink SimPowerSystems prove the performance of the proposed controller against load variation.

• 한국전자통신학회논문지
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• 제18권4호
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• pp.617-624
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• 2023

최근, 전자 제품의 소형화와 저소비전력화 및 향상된 효율과 역률개선이 큰 관심 사항이 되고 있다. 본 논문에서는 PWM 제어기반의 AC-DC 컨버터를 설계, 제작하였다. AC-DC 컨버터는 하나의 정류회로와 하나의 출력전압 제어 회로가 직렬로 연결되는 구조로 설계하였으며, 정류회로는 다이오드 기반 단상 전파전류 회로, 출력전압 제어 회로는 PWM 제어기반의 DC-DC 변환 회로를 적용하였다. PWM 제어를 위한 주 제어장치로 아두이노를 이용하였으며, LCD를 출력 단에 구성하여 제어 결과를 확인할 수 있도록 하였다. 시험회로를 통한 반복 실험들을 통해서 오실로스코프와 LCD에 디스플레이 되는 출력전압과 목표 출력전압의 오차를 확인하였으며, 오실로스코프 측정값을 기준으로 약 5%의 오차율을 보임으로써 제안된 설계 방법론의 유효성을 확인할 수 있었다.

• 전기학회논문지P
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• 제66권2호
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• pp.63-68
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• 2017

This paper proposes a new non-isolated DC conversion circuit topology of the voltage source coupled inductor series resonant high-frequency PFM controlled boost chopper type DC-DC power converter using two in one IGBT power module, which can efficiently operate under a principle of zero current soft switching for wide output regulation voltage setting ranges and wide fluctuation of the input DC side voltage as well as the load variation ranges. Its steady state operating principle and the output voltage regulation characteristics in the open-loop-based output voltage control scheme without PI controller loop are described and evaluated from theoretical and experimented viewpoints. Finally, in this paper the computer-aided simulation steady-state analysis and the experimental results are presented in order to prove the effectiveness and the validity of voltage regulation characteristics of the proposed series resonant zero current soft switching boost chopper type DC-DC power converter circuit using IGBTs which is based on simple pulse frequency modulation strategy more than, 20kHz.