• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.112-115
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• 2002

Previous AC/DC PFC Boost Converter perceives feed forward signal of input and feedback signal of output for average current-mode control. Previous Boost Converter, the quantity of input current will be decreased by the decrease of output current in light load, and also power factor comes to be decreased. Also the efficiency of converter will be decreased by the decrease of power factor. The proposed converter presents the good PFC(Power Factor Correction), low line current hormonic distortions and tight output voltage regulations using non-dissipative snubber. The proposed converter also has a high efficiency by non-dissipative snubber circuit. To show the superiority of this converter is verified through the experiment with a 640W, 100kHz prototype converter.

• Journal of Power Electronics
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• 제16권2호
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• pp.621-630
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• 2016

In this paper, a single current sensor technique (SCST) is proposed for single-phase full-bridge inverters. The proposed SCST measures the currents of multiple branches at the same time, and reconstructs the average inductor, capacitor, and load current in a single switching cycle. Since all of the branches' current in the LC filter and the load are obtained using the SCST, both the inductor and the capacitor current feedback schemes can be selectively applied while taking advantages of each other. This paper also analyzes both of the current feedback schemes from the view point of the closed-loop output impedance. The proposed SCST and the analysis in this paper are verified through experiments on a 3kVA single-phase uninterruptible power supply (UPS).

• 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.

• Journal of Power Electronics
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• 제10권6호
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• pp.673-679
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• 2010

Input-series-output-parallel (ISOP) connected DC-DC converters enable low voltage rating switches to be used in high voltage input applications. In this paper, a DSP is adopted to generate digital phase-shifted PWM signals and to fulfill the closed-loop control function for ISOP connected two full-bridge DC-DC converters. Moreover, a stable output current sharing control strategy is proposed for the system, with which equal sharing of the input voltage and the load current can be achieved without any input voltage control loops. Based on small signal analysis with the state space average method, a loop gain design with the proposed scheme is made. Compared with the conventional IVS scheme, the proposed strategy leads to simplification of the output voltage regulator design and better static and dynamic responses. The effectiveness of the proposed control strategy is verified by the simulation and experimental results of an ISOP system made up of two full-bridge DC-DC converters.

• Journal of Power Electronics
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• 제14권1호
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• pp.40-47
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• 2014

An average current mode control scheme that consistently offers good dynamic performance for LLC series resonant DC-to-DC converters irrespective of the changes in the operational conditions is presented in this paper. The proposed control scheme employs current feedback from the resonant tank circuit through an integrator-type compensation amplifier to improve the dynamic performance and enhance the noise immunity and reliability of the feedback controller. Design guidelines are provided for both current feedback and voltage feedback compensation. The performance of the new control scheme is demonstrated through an experimental 150 W converter operating with 340 V to 390 V input voltage to provide a 24 V output voltage.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전력기술부문
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• pp.65-67
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• 2008

A new pulse width modulation method based on predictive current control strategy is proposed to modulate matrix converters. The predictive current controller utilizes a discrete-time model to predict the future values of output currents and generates proper duty-ratios ta minimize the output current errors. The proposed method uses continuous carrier and establishes a predictive current controller to predetermine duty ratio signal for directly generating gating signals an thus is named "predictive current control PWM(PCCPWM)". The modulation algorithm nd the required equations are derived by using average concept over one switching period. Thus it can be easily extended to other matrix converter topologies, especially with neutral connections, such as sing le-phase ad two-phase matrix converters. The feasibility and validity of the proposed strategy are verified by computer simulation and experimental results.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.560-563
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• 2000

In this paper we proposed AC/DC boost converter to improve input current harmonic reduction in TIG welder. The proposed harmonic reduction circuit with UC2854AN acting on constant switching frequency average current control has a three-loop control structure : the inner current loop the line voltage feed-forward loop and th outer voltage loop. Also we applied the constant current strategy on full bridge IGBT inverter to stabilized the output current using the analog PI controller. To demonstrate the practical significance of the proposed methods some simulation studies and experimental results are presented.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.1920-1923
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• 1991

An online RF power measurement is needed for the full-bridged MOS-FET RF power inverter because the output current and/or voltage waveform is other than sinusoidal. In order to satisfy the requirement, the online measurement of the output power of this type of RF power inverter by the use of the PC-98 personal computer has been presented. The current and voltage waveforms are sensed by the digital oscilloscope probes so as to obtain the instantaeous power and they are entered into the PC98 personal computer so as to average the instantaneous powers. The RF power of up to 1 kw at 1 MHz measured for the power inverter at the output transformer. This method was confirmed to be applied to evaluate the load resistance change with temperature.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.337-340
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• 2000

In this paper, I compared some characteristics between HPA and LPA using Feedforward method. Feedforward method is known for best IMD correction. HPA generated 46.5㏈c at 45.5㏈m output power. But, using feedforward linearing method, I could improve IMD to 67.17㏈c at the same output power. IMD could be improved 20.67㏈ at 45.5㏈m output power. I measured average power, IMD, total current, and efficiency of two amplifier at many different power levels. I could get about 70d3c IMD using feedforward method.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.258-263
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• 1998

A comparative study of single-phase PWM converters having active filtering functions both on ac-input and dc-output sides have been carried out. Based on the function of the dc-output side active filter, two types of configurations, the RPM (ripple power managing) type and the APM (average power managing) type are compared to show their contrastive characteristics. The prototype system using DSP based control algorithms, i.e. deadbeet current control and voltage sensor-less technique using full-order observer, show the availability of the proposed system.