Journal articles: 'Discontinuous operation mode'

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Drews, Daniel, Robert Cuzner, and Giri Venkataramanan. "Operation of Current Source Inverters in Discontinuous Conduction Mode." IEEE Transactions on Industry Applications 52, no. 6 (November 2016): 4865–77. http://dx.doi.org/10.1109/tia.2016.2590466.

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Tetervenoks, Olegs, and Irena Milashevski. "Dimmable LED Drivers Operating in Discontinuous Conduction Mode." Electrical, Control and Communication Engineering 2, no. 1 (April 1, 2013): 27–33. http://dx.doi.org/10.2478/ecce-2013-0004.

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AbstractFor the modern smart lighting systems one of the most attractive LED advantages is the dimming possibility. Many researchers and engineers from the field of lighting engineering are trying to find compromise between the efficiency of LED dimming process and the ease of its implementation. This paper also presents an attempt to improve LED dimmer parameters. Comparative investigation of the operation of buck LED drivers in continuous conduction mode and discontinuous conduction mode are discussed here. The first section of paper briefly describes the controllability parameters of the converter in both of these modes. The positive impact of discontinuous conduction mode on the controllability parameters as well as the results of the analytical estimation and the results of associated experiments are summarized at the end of the first section. The second section describes the impact of discontinuous conduction mode on the losses of LED dimmer. The analytical estimation of power losses in the main converter components for both operation modes as well as the summary of the experiments to identify distribution of power losses between these components are presented in this section. Finally, the conclusions about using discontinuous conduction mode for dimmable LED lamps as well as guidelines for the choosing of the components with the most appropriate parameters are drawn

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Lin, Jian-Hui, Xiao-Ming Wu, Hao Chen, Xi Liu, Tian-Ling Ren, and Li-Tian Liu. "Analyses of vibration-based piezoelectric power generator in discontinuous operation mode." Sensors and Actuators A: Physical 152, no. 1 (May 2009): 48–52. http://dx.doi.org/10.1016/j.sna.2009.02.008.

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Zlateva, Penka, and Krastin Yordanov. "Experimental study of heat pump type air-water for heating system performance." E3S Web of Conferences 112 (2019): 01007. http://dx.doi.org/10.1051/e3sconf/201911201007.

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The operation of an air-to-water heat pump system providing space heating production for an administrative building in Varna has been explored. For this purpose, discontinuous operational mode of the heat pump system during wintertime is considered. Study has been performed by use of real values for external ambient temperature and operating characteristics of the heat pump system. The seasonal efficiency of the heat pump operation has been calculated. Also, the minimal external ambient temperature until the heat pump may work in heating regime and operation duration at outdoor air temperatures higher than the design air temperature can be determined. The economic analysis of the heat pump system exploitation has been made finally.

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Bo-Tao Lin and Yim-Shu Lee. "Power-factor correction using Cuk converters in discontinuous-capacitor-voltage mode operation." IEEE Transactions on Industrial Electronics 44, no. 5 (1997): 648–53. http://dx.doi.org/10.1109/41.633463.

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Lucia, O., J. M. Burdio, L. A. Barragan, C. Carretero, and J. Acero. "Series Resonant Multiinverter with Discontinuous-Mode Control for Improved Light-Load Operation." IEEE Transactions on Industrial Electronics 58, no. 11 (November 2011): 5163–71. http://dx.doi.org/10.1109/tie.2011.2126541.

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Parada Salado, Juan Gerardo, Carlos Alonso Herrera Ramírez, Allan Giovanni Soriano Sánchez, and Martín Antonio Rodríguez Licea. "Nonlinear Stabilization Controller for the Boost Converter with a Constant Power Load in Both Continuous and Discontinuous Conduction Modes." Micromachines 12, no. 5 (May 6, 2021): 522. http://dx.doi.org/10.3390/mi12050522.

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The operation of Boost converters in discontinuous conduction mode (DCM) is suitable for many applications due to the, among other advantages, inductor volume reduction, high efficiency, paralleling, and low cost. Uses in biomedicine, nano/microelectromechanical, and higher power systems, where wide ranges of input/output voltage and a constant power load (CPL) can coexist, are well-known examples. Under extremely wide operating ranges, it is not difficult to change to a continuous conduction mode (CCM) operation, and instability, chaos, or bifurcations phenomena can occur regardless of the conduction mode. Unfortunately, existing control strategies consider a single conduction mode or linearized models because only slight resistive/CPL power level or input/output voltage variations (and no conduction mode changes) were expected. In this paper, new mathematical models for the Boost converter (with resistive or CPL) that are conduction mode independent are presented and validated. Since the open-loop dynamics of the proposed CPL model is unstable, a nonlinear control law capable of stabilizing the boost converter regardless of the conduction mode is proposed. A stability analysis based on a common-Lyapunov function is provided, and numerical and experimental tests are presented to show the proposal’s effectiveness.

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Al-Obaidly, Ali H. A. "THE ANALYSIS OF THE CONTINUOUS AND DISCONTINUOUS OPERATION MODE BY USING MATHEMATICA PROGRAM." Journal of Harmonized Research in Engineering 7, no. 4 (December 30, 2019): 30. http://dx.doi.org/10.30876/johr.7.4.2019.30-39.

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Sadarnac, D., W. Abida, and C. Karimi. "The Double Discontinuous Mode Operation of a Converter: A Method for Soft Switching." IEEE Transactions on Power Electronics 19, no. 2 (March 2004): 453–60. http://dx.doi.org/10.1109/tpel.2003.823171.

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Lee, Y. S., S. J. Wang, and S. Y. R. Hui. "Modeling, analysis, and application of buck converters in discontinuous-input-voltage mode operation." IEEE Transactions on Power Electronics 12, no. 2 (March 1997): 350–60. http://dx.doi.org/10.1109/63.558762.

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Yang, Jianbo, Weiping Zhang, Faris Al-Naemi, and Xiaoping Chen. "Analysis and Modeling of Buck Converter in Discontinuous-Output-Inductor-Current Mode Operation." Energy and Power Engineering 05, no. 04 (2013): 850–56. http://dx.doi.org/10.4236/epe.2013.54b163.

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Kumar, Rustam, Chih-Chiang Wu, Ching-Yao Liu, Yu-Lin Hsiao, Wei-Hua Chieng, and Edward-Yi Chang. "Discontinuous Current Mode Modeling and Zero Current Switching of Flyback Converter." Energies 14, no. 18 (September 21, 2021): 5996. http://dx.doi.org/10.3390/en14185996.

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The flyback converters are widely used in low power applications. The switch typically requires 600 V breakdown voltage in order to perform large step-down voltage. Thus, slight variation on the switch control can either permanently damage the switch or decrease the efficiency of the power conversion. In order to achieve higher power efficiency, the previous literature suggested operating the flyback converter in the discontinuous current mode (DCM). It is then required to understand the critical conditions of the DCM through analyzing the dynamic behavior and discontinuous current mechanism. This paper started from the current waveform analyses, proceeded to the derivation of zero current switching (ZCS) formulation, and finally reached the necessary conditions for the DCM. The entire DCM operation was divided into three phases that subsequently affect the result of the zero voltage switching (ZVS) and then to the ZCS. The experiment shows a power efficiency of over 96% when the output power is around 65 W. The switch used in this paper is a Gallium Nitride High-Electron-Mobility Transistor (GaN HEMT) that is advantageous at the high breakdown voltage up to 800 V. The important findings from the experiments include that the output power increases with the increasing input DC voltage and the duty cycle is rather linearly decreasing with the increasing switching frequency when both the zero voltage switching (ZVS) and ZCS conditions are satisfied simultaneously.

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Gunasekaran, D., and L. Umanand. "Integrated magnetics based multi-port bidirectional DC–DC converter topology for discontinuous-mode operation." IET Power Electronics 5, no. 7 (August 1, 2012): 935–44. http://dx.doi.org/10.1049/iet-pel.2011.0492.

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Stojanović, Željko, and Denis Pelin. "Limitations of Bifurcation Diagrams in Boost Converter Steady-State Response Identification." International journal of electrical and computer engineering systems 8, no. 2 (2017): 59–65. http://dx.doi.org/10.32985/ijeces.8.2.3.

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Steady-state responses of the boost converter operating in discontinuous conduction mode of operation are identified by using bifurcation diagrams as a typical simulation tool for identification of steady-state responses. The structure of simulated bifurcation diagrams is dependent on the initial period of sampling and the initial instant of sampling. The influence of these parameters on calculation of bifurcation diagrams was studied. Some possible issues, pitfalls and misinterpretations are commented as well as some recommendations about steady-state response identification are given

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15

Luo, Fang Lin. "Switched-Capacitorized DC/DC Converters." Applied Mechanics and Materials 310 (February 2013): 453–65. http://dx.doi.org/10.4028/www.scientific.net/amm.310.453.

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Switched capacitor DC/DC converters are new prototype of DC/DC conversion technology. Since switched capacitor can be integrated into a power IC chip, consequently, these converters have small size and high power density. Switched capacitor can be used in voltage-lift technique to construct DC/DC converters. The clue is that for the converters operating in discontinuous input current mode (DICM) the switched capacitors can be charged during the input current discontinuous period. The switched capacitors are charged to the source voltage during the switch-off period. They will join the conversion operation during switch-on period, and the stored energy in them will be delivered through further elements to the load. These converters are called switched-capacitorized DC/DC converters. Simulation and experimental results are provided for verification of this design.

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Linz, Mario, Jörg Exner, Jaroslaw Kita, Florian Bühner, Martin Seipenbusch, and Ralf Moos. "Discontinuous Powder Aerosol Deposition: An Approach to Prepare Films Using Smallest Powder Quantities." Coatings 11, no. 7 (July 13, 2021): 844. http://dx.doi.org/10.3390/coatings11070844.

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This work shows that the powder aerosol deposition (PAD) method allows the formation of films in powder quantities of less than 60 mg, rather than the large amounts that are typically required for conventional powder aerosol deposition systems. This was achieved by changing the operation mode to a discontinuous one, resulting in operation times of several seconds. Semiconducting strontium titanate ferrate SrTi0.65Fe0.35O3−δ (STF35) was used as the powder to prove the equal behavior in terms of adhesion, film quality and electric conductivity compared to conventional powder-aerosol-deposited films.

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17

Suntio, Teuvo. "Modeling and Analysis of a PCM-Controlled Boost Converter Designed to Operate in DCM." Energies 12, no. 1 (December 20, 2018): 4. http://dx.doi.org/10.3390/en12010004.

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Peak current-mode (PCM) control has been a very popular control method in power electronic converters. The small-signal modeling of the dynamics associated with PCM control has turned out to be extremely challenging. Most of the modeling attempts have been dedicated to the converters operating in continuous conduction mode (CCM) and just a few to the converters operating in discontinuous operation mode (DCM). The DCM modeling method published in 2001 was proven recently to be very accurate when applied to a buck converter. This paper provides the small-signal models for a boost converter and analyses for the first time its real dynamic behavior in DCM. The objectives of this paper are as follows: (i) to provide the full-order dynamic models for the DCM-operated PCM-controlled boost converter; (ii) to analyze the accuracy of the full and reduced-order dynamic models; and iii) to verify the validity of the high-frequency extension applied in the DCM-operated PCM-controlled buck converter in the case of the boost converter. It is also shown that the DCM-operated boost converter can operate only in even harmonic modes, similar to all the CCM-operated PCM-controlled converters. In the case of the DCM-operated PCM-controlled buck converter, its operation in the odd harmonic modes is the consequence of an unstable pole in its open-loop power-stage dynamics.

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Shahir, Farzad Mohammadzadeh, Ebrahim Babaei, and Murtaza Farsadi. "A New Structure for Nonisolated Boost DC–DC Converter." Journal of Circuits, Systems and Computers 26, no. 01 (October 4, 2016): 1750012. http://dx.doi.org/10.1142/s0218126617500128.

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In this paper, a new structure of nonisolated boost DC–DC converters is proposed. The operation of the proposed structure in continuous conduction mode (CCM) and discontinuous conduction mode (DCM) is presented. Then, the critical inductance relation between CCM and DCM is obtained. The voltage gain and current stress of switches are calculated. Finally, the validity of the presented theoretical issues is reconfirmed by using simulation results obtained from PSCAD/EMTDC software.

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Venkata Mohan, S., C. Nagendranatha Reddy, A. Naresh Kumar, and J. Annie Modestra. "Relative performance of biofilm configuration over suspended growth operation on azo dye based wastewater treatment in periodic discontinuous batch mode operation." Bioresource Technology 147 (November 2013): 424–33. http://dx.doi.org/10.1016/j.biortech.2013.07.126.

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20

Zhao, Ben, Yigeng Huangfu, and Alexander Abramovitz. "Derivation of OCC Modulator for Grid-Tied Single-Stage Buck-Boost Inverter Operating in the Discontinuous Conduction Mode." Energies 13, no. 12 (June 18, 2020): 3168. http://dx.doi.org/10.3390/en13123168.

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This paper is concerned with the derivation of a one-cycle controller for driving a single-stage buck-boost DC-AC micro-inverter in grid-tied applications. The topology under study is based on a full-bridge switch arrangement with no unfolder circuit. The proposed micro-inverter attains a high gain by applying a multi-winding tapped inductor and, therefore, can operate at grid-level voltage without using a DC-DC step-up stage. To minimize the switching loss, the proposed inverter is operated in the discontinuous conduction mode. The operation principles of the proposed topology in the discontinuous conduction mode are discussed and analyzed. Based on the analysis, the one-cycle control law and modulator circuitry needed to control the proposed micro-inverter are developed. The feasibility of the proposed modulation scheme is verified by simulation.

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21

Yang, Fei, Xinbo Ruan, Gang Wu, and Zhihong Ye. "Discontinuous-Current Mode Operation of a Two-Phase Interleaved Boost DC–DC Converter With Coupled Inductor." IEEE Transactions on Power Electronics 33, no. 1 (January 2018): 188–98. http://dx.doi.org/10.1109/tpel.2017.2669401.

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22

Chiniforoosh, S., H. Atighechi, A. Davoudi, J. Jatskevich, A. Yazdani, S. Filizadeh, M. Saeedifard, et al. "Dynamic Average Modeling of Front-End Diode Rectifier Loads Considering Discontinuous Conduction Mode and Unbalanced Operation." IEEE Transactions on Power Delivery 27, no. 1 (January 2012): 421–29. http://dx.doi.org/10.1109/tpwrd.2011.2168983.

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23

Salimi, Mahdi, and Adel Zakipour. "General Purpose Adaptive and Nonlinear Controller Design for DC-DC Converters in Discontinuous Conduction Mode Operation." EPE Journal 24, no. 3 (September 2014): 14–22. http://dx.doi.org/10.1080/09398368.2014.11742748.

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Vecchiati, Giorgio, Francesco Fagioli, Giancarlo Torsi, Clinio Locatelli, Dionisio Mazzotta, and Antonella Pagnoni. "Standardless Analysis of Hg with the Cold Vapor Method: Evaluation of the Best Use of Modern Instrumentation." Applied Spectroscopy 56, no. 7 (July 2002): 859–62. http://dx.doi.org/10.1366/000370202760171527.

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The so-called cold vapor method is extensively used in atomic absorption spectroscopy for the quantitation of Hg and hydride forming elements. In the case of Hg it is possible to take advantage of the standardless method of analysis (which gives a quantitative result from a single measurement) if a stannous salt is used as a reducing agent. This type of analysis, which has the advantages of high sensitivity, low analysis time, and easy checking of the perfect working conditions of all the components of the apparatus, can be made with very slightly altered commercial instruments if flowmeters of good accuracy and precision are used. The mode of operation of modern commercial instruments can be either discontinuous, with a chromatographic-like injector, or continuous. A survey of the instruction manuals shows that virtually all manufacturers prefer the discontinuous mode. Our experimental results demonstrate that only with the continuous mode, if sufficient sample volume is available, is it possible to use the standardless method of analysis.

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Cittanti, Davide, Matteo Gregorio, Fabio Mandrile, and Radu Bojoi. "Full Digital Control of an All-Si On-Board Charger Operating in Discontinuous Conduction Mode." Electronics 10, no. 2 (January 17, 2021): 203. http://dx.doi.org/10.3390/electronics10020203.

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This paper deals with the design, tuning and implementation of a digital controller for an all-Si electric vehicle (EV) on-board battery charger operated in discontinuous conduction mode (DCM). This charger consists of two cascaded conversion stages: a front-end power factor corrector (PFC) with two interleaved legs and an isolated phase-shifted full bridge DC/DC converter. Both stages operate in DCM over the complete battery charging power range, allowing lower inductance values for both the PFC and the DC/DC filtering elements. Moreover, DCM operation ensures a large reduction of the reverse-recovery losses in the power diodes, enabling the adoption of relatively cheap Si devices. The main goal of the work is to address the well-known DCM control challenges, leveraging a novel control strategy for both converter stages. This control scheme counteracts the DCM system non-linearities with a proper feed-forward contribution and an open-loop gain adjustment, ensuring consistent dynamical performance over the complete operating range. The designed controllers are tuned analytically, taking into account the delay components related to the digital implementation. Finally, the proposed control strategy is implemented on a single general purpose microcontroller unit (MCU) and its performance is experimentally validated on a 3.3 kW battery charger prototype.

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Juan, Yu Lin. "A Wide Voltage-Ratio Dual-Output DC Converter for Charging Series-Connected Batteries." Energies 12, no. 9 (April 30, 2019): 1650. http://dx.doi.org/10.3390/en12091650.

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In this study, a dual-output converter with a wide input voltage range is proposed for directly equalized charging of series-connected batteries without additional power conversion losses. Compared with most of the equalized charging topologies, such as the those with a multi-winding transformer or voltage multiplier, the proposed converter could be applied to different voltage conversion ratio applications. The proposed converter is capable not only of step-down but also step-up/down power conversions for different input voltage levels. By operating in discontinuous conduction mode, the diode reverse recovery losses can be eliminated and operation stability can also be enhanced. The operation principles and design criteria are both illustrated. A prototype of charging two series-connected LiFePO4 batteries is constructed. Corresponding experimental results of different input voltage levels are provided to verify the performance and validity.

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Chang, Yong-Nong, Hung-Liang Cheng, Hau-Chen Yen, Chien-Hsuan Chang, and Wei-Di Huang. "An Interleaved DC/DC Converter with Soft-switching Characteristic and high Step-up Ratio." Applied Sciences 10, no. 6 (March 22, 2020): 2167. http://dx.doi.org/10.3390/app10062167.

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This study presents a dc/dc converter featuring soft-switching characteristic, high conversion efficiency, and high step-up ratio. The proposed circuit is composed of two parallel-connected boost converters. Only one coupled inductor is used to replace inductors of the boost converters which are interleaved operated at discontinuous-conduction mode (DCM). The current ripples at the input and the output terminals are reduced due to the interleaved operation. By freewheeling the current of the coupled inductor to discharge the stored electric charges in the parasitic capacitors of the active switches, both active switches can fulfill zero-voltage switching on (ZVS). Owing to DCM operation, the freewheeling diodes can fulfill zero-current switching off (ZCS). Therefore, the power conversion efficiency is improved. The operation principle for each operation mode is analyzed in detail and design equations for the component parameters are provided in this report. Finally, a prototype 200 W 48–400 V converter was implemented and measured to demonstrate the effectiveness of the proposed circuit.

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Cao, Taiqiang, Fang You, Fei Zhang, Ping Yang, Qian Luo, and Jun Wang. "DSP-Based Control of Tri-State Boost PFC Converter with High Input Power Factor for Wide Range of Load Variations." Journal of Circuits, Systems and Computers 24, no. 05 (April 8, 2015): 1550072. http://dx.doi.org/10.1142/s0218126615500723.

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Tri-state boost power factor correction (PFC) converter operating in pseudo-continuous-conduction mode (PCCM) is analyzed in this paper. The connection of power switch in parallel with inductor makes the boost converter operate in PCCM, which provides an additional degree of control freedom by inductor current freewheeling operation mode. Compared with boost PFC converter operating in continuous conduction mode (CCM) and discontinuous conduction mode (DCM), tri-state boost PFC converter extends the load range and is therefore more suitable for wide range of load variation. However, for universal input applications, the input power factor (PF) of the tri-state boost PFC converter is relatively low when the sinusoidal reference current control strategy is used. To improve the PF over the whole input voltage range, the input current and PF expressions of the tri-state boost PFC converter is derived and the non-sinusoidal reference current control strategy is proposed. A 400 W prototype of the tri-state boost PFC converter is built by using digital signal processing (DSP) as the controller. The experimental results verify the analysis results.

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Strobel, Nina, and Eberhard Abele. "Decentral Control Strategies for Demand-side Management by Industrial Heating and Cooling Devices with Discontinuous Operation Mode." Procedia CIRP 69 (2018): 360–65. http://dx.doi.org/10.1016/j.procir.2017.11.059.

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Salimi, Mahdi, Jafar Soltani, Adel Zakipour, and Navid Reza Abjadi. "Hyper‐plane sliding mode control of the DC–DC buck/boost converter in continuous and discontinuous conduction modes of operation." IET Power Electronics 8, no. 8 (August 2015): 1473–82. http://dx.doi.org/10.1049/iet-pel.2014.0578.

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Ho, P. K., C. K. Lee, and T. P. Leung. "Matlab™ Simulation of an Exact Mathematical Model of the Permanent Magnet Synchronous Motor With a Discontinuous Current Mode Operation." International Journal of Modelling and Simulation 23, no. 1 (January 2003): 60–72. http://dx.doi.org/10.1080/02286203.2003.11442256.

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Parada-Salado, Juan-Gerardo, Martín-Antonio Rodríguez-Licea, Allan-Giovanni Soriano-Sanchez, Omar-Fernando Ruíz-Martínez, Alejandro Espinosa-Calderon, and Francisco-Javier Pérez-Pinal. "Study on Multiple Input Asymmetric Boost Converters with Simultaneous and Sequential Triggering." Electronics 10, no. 12 (June 13, 2021): 1421. http://dx.doi.org/10.3390/electronics10121421.

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Paralleled boost asymmetric configurations operating in discontinuous conduction mode (DCM) are suitable for integrating dissimilar green energy generating sources and control algorithms in versatile scenarios where voltage step-up, low cost, stable operation, low output ripple, uncomplicated design, and acceptable efficiency are needed. Unfortunately, research has mainly been conducted on the buck, sepic, switched-capacitor, among other asymmetric configurations operating in continuous conduction mode (CCM), to the authors’ knowledge. For asymmetric boost type topologies, achieving simultaneous CCM is not a trivial task, and other problems such as circulating currents arise. Research for interleaved converters cannot be easily extended to asymmetric boost topologies due to the dissimilarity of control algorithms and types of sources and parallel stages. This paper analytically establishes properties of stability, output ripple, output voltage, and design for asymmetrical paralleled boost converters operating in DCM with simultaneous or phase delayed (sequential) triggering. A 300 W experimental design and the respective tests allow validation of such properties, resulting in an easy-to-implement configuration with acceptable efficiency.

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Sun, Bai Qing, Xiu Wei Ge, and Yi Biao Sun. "Dynamical Integral Sliding Mode Control for Permanent Magnet Ring Torque Motor." Advanced Materials Research 383-390 (November 2011): 799–804. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.799.

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In view of the characteristics of numerical control turntable servo system directly driven by permanent magnet ring torque motor, which is susceptible to load disturbance and parameter variation, a dynamic-integral sliding mode position controller is designed. Dynamic sliding mode control means making differential operation to switching function of conventional sliding mode control, thus, a new switching function can be obtained. The discontinuous terms are transferred to first or higher derivative of control quantity. Therefore, the dynamic sliding mode control law is continuous timely, and then the chattering can be effectively reduced. Meanwhile, in order to ensure the steady-state accuracy of system, the integral term is introduced in the switching function to realize dynamic integral sliding mode control. The simulation results indicate that dynamic-integral sliding mode control of permanent magnet ring torque motor has favorable dynamic response and strong robustness, and it is effective to weaken the chattering.

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Trachtenberg, Or, and Alon Kuperman. "Quadrature Demodulator-Assisted Estimation of Load Voltage and Resistance Based on Primary-Side Information of a Wireless Power Transfer Link." Electronics 10, no. 15 (August 2, 2021): 1858. http://dx.doi.org/10.3390/electronics10151858.

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This paper proposes an algorithm for the extraction of primary-side first harmonic voltage and current components for inductive wireless power transfer (WPT) links by employing quadrature demodulation. Such information allows for the accurate estimation of corresponding receiver-side components and hence permits the monitoring of the output voltage and resistance necessary for protection and/or control without using either sensors or feedback communication. It is shown that precision estimation is held as long as the parameter values of the system are known and the phasor-domain equivalent circuit is valid (i.e., in continuous conduction mode). On the other hand, upon light load operation (i.e., in discontinuous conduction mode), the proposed technique may still be employed if suitable nonlinear correction is employed. The methodology is applied to a 400 V, 1 kW inductive WPT link operating at a load-independent-voltage-output frequency and is well-verified both by simulations and experiments.

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Do, Hyun Lark. "AC-DC Converter with Power Factor Correction Function." Applied Mechanics and Materials 241-244 (December 2012): 763–66. http://dx.doi.org/10.4028/www.scientific.net/amm.241-244.763.

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An AC -DC converter with power factor correction (PFC) function is proposed in this paper. In the proposed converter, the boost PFC stage and the active-clamp DC-DC converter stage are merged into a single converter to reduce the overall cost and improve the power density. An active-clamp DC-DC converter stage can suppress the switch voltage stresses and provide zero-voltage-switching (ZVS) operation of the switches. The boost converter in PFC stage operates in discontinuous conduction mode (DCM) and it provides naturally high power factor. Due to the ZVS operation, the switching losses of the proposed converter are significantly reduced and the efficiency is improved. Steady-state analysis is performed. Simulation results are also provided to verify the effectiveness of the proposed converter.

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Cheng, Hung-Liang, Yong-Nong Chang, Lain-Chyr Hwang, Hau-Chen Yen, Shun-Yu Chan, and Wen-Fu Yang. "A High-Power-Factor Dimmable LED Driver with Integrated Boost Converter and Half-Bridge-Topology Converter." Applied Sciences 10, no. 8 (April 16, 2020): 2775. http://dx.doi.org/10.3390/app10082775.

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This paper proposes a dimmable light-emitting diode (LED) driver featuring a high power factor and zero-voltage switching on (ZVS). The circuit is obtained by integrating a boost converter and a dc-dc converter with half-bridge topology. The high power factor is achieved by operating the boost converter in discontinuous current mode (DCM). The LEDs are dimmed by the control scheme of asymmetrical pulse-width modulation (ASPWM). The developed circuit eliminates the inherited dc-offset current of the transformer in a conventional asymmetrical half-bridge converter by introducing a balance capacitor. Both active switches can operate at ZVS by freewheeling the boost inductor current and the transformer magnetizing current to discharge the energy stored in their parasitic capacitance. The circuit operation is analyzed in detailed, and mathematical equations are derived. Finally, a 115-W prototype circuit for driving high brightness LEDs was built and tested. The experimental results verify the feasibility of the proposed LED driver with satisfactory performance. It can achieve a high power factor and ZVS operation.

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Mahesh Gowda, N. M., and S. S. Parthasarathy. "Selection of Inductor and Snubber Capactor to Optimize the Size and Efficiency of DC-DC Switching Power Converter." Asian Journal of Engineering and Applied Technology 7, no. 1 (May 5, 2018): 49–52. http://dx.doi.org/10.51983/ajeat-2018.7.1.977.

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This paper presents a selection of inductor and snubber capacitor in non-isolated synchronous DC-DC switching power converter. The circuit is made to operate in Synchronous Discontinuous Conduction Mode (SDCM)/Forced Continuous Conduction Mode (FCCM) of operation for minimum inductor value, to reduce the size, weight and cost of the converter. The turn off loss of the switch induced by SDCM of operation is minimized by connecting snubber capacitor across the transistor switch. Before the switch is turned ON, snubber capacitor requires certain amount of energy must be stored in the inductor to discharge the capacitor energy [1]. The question is how much capacitor and inductor value is required. A series of MATLAB script are executed to find minimum inductor value for FCCM of operation and to select snubber capacitor for maximum efficiency. Complementary gate signals are used to control the ON and OFF of main and auxiliary switch. SDCM of operation due to complementary control gate signal scheme, minimum turn on loss of the transistor switch and low diode reverse recovery loss are achieved. Thus the Zero Voltage Resonant Transition (ZVRT) of transistor switch is realized, both turn on and turn off loss is minimized and also removes the parasitic ringing in inductor current.

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Muthukaruppasamy, S., and A. Abudhahir. "Design and Implementation of Sliding Mode Controller Plus Fuzzy Logic Controller for Discontinuous Conduction Mode Operation of Negative Output Elementary Super Lift Luo Converter." Journal of Computational and Theoretical Nanoscience 13, no. 11 (November 1, 2016): 8505–21. http://dx.doi.org/10.1166/jctn.2016.6005.

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Henninger, Matthias, Wolfgang Schlüter, Dominik Jeckle, and Jörg Schmidt. "Simulation Based Studies of Energy Saving Measures in the Aluminum Tool and Die Casting Industry." Applied Mechanics and Materials 856 (November 2016): 131–39. http://dx.doi.org/10.4028/www.scientific.net/amm.856.131.

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This study, which focuses on analyzing aluminum melting and die casting procedures is part of the Smart Melting project in the research network Green Factory Bavaria (GFB). The aim of the present research project is to investigate these procedures and to suggest measures to increase the overall energy efficiency. The analysis starts with the capture of the operating structure, the relations between supply and consumption of liquid aluminum and an evaluation of aluminum furnaces themselves. The study concentrates on shaft furnaces whose specific energy consumption is 25 % higher than stated by the manufacturers. At the same time the melting capacity of the furnaces ranges at the lower end according to the manufacturer's data. The reason for this deviation is a discontinuous operation mode due to demand fluctuations. Consequently the flue gas has still a high temperature which means a high waste of energy. Based on these facts the furnace charge and operation mode have to be optimized and the high temperature flue gas can be used to preheat the pig aluminum.A numerical model of aluminum furnaces is applied to investigate this optimization potential. This model can simulate either a single aluminum furnace (case 1) or a furnace integrated in the entire manufacturing plant (case 2). The advantage of case 1 is the furnace's operation on its most efficient point because there is no influence of the die casting process. In case 1 an improvement of the furnace charge leads to a higher capacity utilization and therefore to a reduction of 30 % specific energy consumption and a 50 % increase of melting capacity. Whereas in case 2 the simulation of the entire manufacturing plant results in a rise of 25 % melting capacity and a 16 % decrease of specific energy consumption. The simulation proved increasing energy efficiency due to preheating the pig aluminum in both cases.

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Chernoff, Donald A. "High-resolution chemical mapping using tapping mode AFM with phase contrast." Proceedings, annual meeting, Electron Microscopy Society of America 53 (August 13, 1995): 888–89. http://dx.doi.org/10.1017/s0424820100140816.

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Introduction. A challenging problem in materials analysis is imaging the microstructure of composite surfaces. Some examples of composite surfaces are: contamination deposits, discontinuous (i.e. defective) thin films, devices built of composite materials, and cross-sectional specimens of composite materials. Techniques such as XPS and SIMS can provide detailed information about the chemical species present on the surface, but only average information is obtained for areas smaller than a few (μm wide. Auger can have sub-micron spatial resolution, but it provides little useful information about organic materials and it is difficult to use on insulating surfaces. In contrast, we have developed a new method for imaging chemical domains with spatial resolution of 10-20 nm. In principle, this method may be used on any surface.The TappingMode™ AFM1 uses an oscillating cantilever whose motion can be characterized by its amplitude and phase relative to its driver. In its most common mode of operation, this AFM uses the amplitude signal to sense the specimen surface, control the Z piezo and create a height image.

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Barakhoev, A. L., O. I. Tikhon, and V. V. Tuboltsev. "Study of the operating modes of the high voltage power source for barrier type discharge excitation." Doklady BGUIR 19, no. 1 (February 23, 2021): 46–51. http://dx.doi.org/10.35596/1729-7648-2021-19-1-46-51.

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The issues related to the features of operation and modes setting of a high-voltage switching power source based on a sequential autonomous resonant inverter with reverse diodes used to excite an atmospheric pressure barrier type discharge are discussed in the article. It is indicated that the characteristic features of the autonomous resonant inverters operation are the occurrence of damped voltage fluctuations in the LC circuit of the inverter, as well as the dependence of the output alternating voltage on the ratio of the inverter operating frequency (thyristor switching frequency) to the natural resonant frequency of the LC circuit. Depending on this ratio, the inverter can operate in discontinuous, boundary and continuous current mode. The amplitude and shape of the inverter output voltage were controlled using a 1:1000 voltage divider with a C1-65A oscilloscope. The shape of the gate trigger pulses was obtained using a C1-167 oscilloscope. It is established that when the gate trigger pulses are asymmetrical relative to each other due to the operation features of the step-up transformers, the value of the alternating high-voltage at the inverter output is insufficient to excite the atmospheric pressure barrier type discharge. In the case of the gate trigger pulses symmetry, the output voltage of the inverter stage reaches the values required for the breakdown of the dielectric medium. Oscillograms of the inverter output voltage while adjusting its operating frequency are obtained. It is shown that the amplitude value of the voltage at the gas-discharge load increases as the operating frequency of the inverter increases. For the gate trigger pulses frequency of 250 Hz the value of the inverter output voltage amplitude was 3.4 kV, for 460 Hz – 4.0 kV, and for 550 Hz – 4.2 kV.

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Hahn, G., and M. Meyer. "Sample-hold technique for analysis of respiratory gas composition at high breathing frequencies." Journal of Applied Physiology 64, no. 6 (June 1, 1988): 2684–91. http://dx.doi.org/10.1152/jappl.1988.64.6.2684.

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A gas sampling device is described for continuous monitoring of respiratory gas composition that is applicable to experimental conditions when the breathing frequency is very high (greater than 2 Hz) and the response time of conventional gas analyzers becomes a critical limiting factor. The system utilizes the principle of discontinuous gas collection at any selected point of the respiratory cycle facilitated by ultraspeed piezoelectric valves and includes provision for sample-hold characteristics. Two distinct modes of operation are supported. In phase-locked mode gas sampling is synchronous with breathing frequency. In scanning mode gas collection is asynchronous with breathing frequency. Phase-locked mode may be used for continuous monitoring of end-tidal gas concentrations, whereas scanning mode is intended for assessing the gas concentration profile throughout the respiratory cycle. The system may be applied to steady breathing encountered in mechanical ventilation at high frequency or during quasi-steady breathing observed in panting animals. Combined with a respiratory mass spectrometer, the system has been used for measurement of gas concentrations in alveolar gas mixtures at breathing frequencies ranging from 3 to 30 Hz that were otherwise not amenable to rapid measuring techniques.

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Zheng, Wen-Ming, Wen-Liang Zeng, Chi-Wa U, Chi-Seng Lam, Yan Lu, Sai-Weng Sin, Man-Chung Wong, and Rui Paulo Martins. "Analysis, Design and Control of an Integrated Three-Level Buck Converter under DCM Operation." Journal of Circuits, Systems and Computers 29, no. 01 (March 12, 2019): 2050011. http://dx.doi.org/10.1142/s0218126620500115.

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A three-level buck (TLB) converter has the characteristics of higher voltage conversion efficiency, lower inductor current ripples, output voltage ripples and voltage stresses on switches when compared with the buck converters in continuous conduction mode (CCM). With a TLB converter integrated on a chip, we cannot avoid its discontinuous conduction mode (DCM) operation due to a smaller inductance and load variation. In this paper, we’ll present and discuss the analysis, design and control of a TLB converter under DCM operation, implemented in a 65[Formula: see text]nm CMOS process. Transistor level simulation results show that when the TLB converter operates at 100[Formula: see text]MHz with a 5[Formula: see text]nH on-chip inductor, a 10[Formula: see text]nF output capacitor and a 10[Formula: see text]nF flying capacitor, it can achieve an output conversion range of 0.7–1.2[Formula: see text]V from a 2.4[Formula: see text]V input supply, with a peak efficiency of 81.5%@120[Formula: see text]mW. The output load transient response is 100[Formula: see text]mV with 101[Formula: see text]ns for undershoot, and 86[Formula: see text]mV with 110[Formula: see text]ns for overshoot when [Formula: see text]–100[Formula: see text]mA. The maximum output voltage ripple is less than 19[Formula: see text]mV.

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LAI, Y. M., C. K. TSE, and P. MEHTA. "A COMPUTER METHOD FOR THE FORMULATION OF AVERAGED MODELS FOR DC/DC POWER CONVERTER CIRCUITS." Journal of Circuits, Systems and Computers 05, no. 03 (September 1995): 373–91. http://dx.doi.org/10.1142/s0218126695000230.

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A computer method for deriving averaged circuit models for a class of power converter circuits is proposed. The proposed method is applicable to any dc/dc converter circuit whose switching frequency is much greater than the natural frequency of each constituent circuit topology. The method starts with decomposing the original circuit into two multiport sub-circuits. One contains the "fast" part, called the Minimum Separable Switching Configuration (MISSCO), and the other contains the remaining "slow" part of the circuit. A hybrid matrix that relates the port voltages and currents of the MISSCO to these constant sources is determined for each switching cycle. By applying one-cycle averaging operation to the hybrid matrices, the low frequency averaged model of the MISSCO is derived. This averaged model can then be combined with the rest of the circuit to form a complete equivalent circuit. For brevity we demonstrate the method in this paper for DC/DC converter circuits in the absence of parasitics. To illustrate the proposed method, the Ćuk converter is considered and its averaged model is derived for the discontinuous inductor-current mode of operation.

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Mohan, S. Venkata, S. Shailaja, M. Rama Krishna, K. B. Reddy, and P. N. Sarma. "Bioslurry phase degradation of di-ethyl phthalate (DEP) contaminated soil in periodic discontinuous mode operation: Influence of bioaugmentation and substrate partition." Process Biochemistry 41, no. 3 (March 2006): 644–52. http://dx.doi.org/10.1016/j.procbio.2005.08.018.

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Pravica, Luka, Damir Sumina, Tin Barisa, Marinko Kovacic, and Igor Colovic. "Flying Start of a Permanent Magnet Wind Power Generator Based on a Discontinuous Converter Operation Mode and a Phase-Locked Loop." IEEE Transactions on Industrial Electronics 65, no. 2 (February 2018): 1097–106. http://dx.doi.org/10.1109/tie.2017.2733453.

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Venkata Mohan, S., N. Chandrasekhara Rao, and P. N. Sarma. "Simulated acid azo dye (Acid black 210) wastewater treatment by periodic discontinuous batch mode operation under anoxic–aerobic–anoxic microenvironment conditions." Ecological Engineering 31, no. 4 (December 2007): 242–50. http://dx.doi.org/10.1016/j.ecoleng.2007.07.003.

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Karimi, Mohsen, Mohammad Pichan, Adib Abrishamifar, and Mehdi Fazeli. "An improved integrated control modeling of a high-power density interleaved non-inverting buck-boost DC-DC converter." World Journal of Engineering 15, no. 6 (December 3, 2018): 688–99. http://dx.doi.org/10.1108/wje-11-2017-0360.

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PurposeThis paper aims to propose a novel integrated control method (ICM) for high-power-density non-inverting interleaved buck-boost DC-DC converter. To achieve high power conversion by conventional single phase DC-DC converter, inductor value must be increased. This converter is not suitable for industrial and high-power applications as large inductor value will increase the inductor current ripple. Thus, two-phase non-inverting interleaved buck-boost DC-DC converter is proposed.Design/methodology/approachThe proposed ICM approach is based on the theory of integrated dynamic modeling of continuous conduction mode (CCM), discontinuous conduction mode and synchronizing parallel operation mode. In addition, it involves the output voltage controller with inner current loop (inductor current controller) to make a fair balancing between two stages. To ensure fast transient performance, proposed digital ICM is implemented based on a TMS320F28335 digital signal microprocessor.FindingsThe results verify the effectiveness of the proposed ICM algorithm to achieve high voltage regulating (under 0.01 per cent), very low inductor current ripple (for boost is 1.96 per cent, for buck is 1.1) and fair input current balance between two stages (unbalancing current less than 0.5A).Originality/valueThe proposed new ICM design procedure is developed satisfactorily to ensure fast transient response even under high load variation and the solving R right-half-plane HP zeros of the CCM. In addition, the proposed method can equally divide the input current of stages and stable different parallel operation modes with large input voltage variations.

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Ahmad, Fiaz, Akhtar Rasool, Esref Emre Ozsoy, Asif Sabanoviç, and Meltem Elitas. "A robust cascaded controller for DC-DC Boost and Cuk converters." World Journal of Engineering 14, no. 5 (October 2, 2017): 459–66. http://dx.doi.org/10.1108/wje-10-2016-0118.

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Purpose This paper aims to propose a robust cascaded controller based on proportional-integral (PI) and continuous sliding mode control. Design/methodology/approach Cascaded control structure is an attractive control scheme for DC-DC power converters. It has a two-loop structure where the outer loop contains PI controller and the inner loop uses sliding mode control (SMC). This structure thus combines the merits of both the control schemes. However, there are some issues that have prohibited its adoption in industry, the discontinuous nature of SMC which leads to variable switching frequency operation and is hard to realize practically. This paper attempts to overcome this issue by changing the discontinuous functionality of SMC to continuous by utilizing the concept of equivalent control. Findings The robustness of the controller designed is verified by considering various cases, namely, ideal case with no uncertainties, sudden variation of input supply voltage, load resistance, reference voltage, circuit-parameters and for noise disturbance. The controller effectiveness is validated by simulating the DC-DC boost and Cuk converters in SimPowerSystems toolbox of MATLAB/Simulink. It is shown that the performance of the proposed controller is satisfactory, and both reference output voltage and inductor current are tracked with little or no sensitivity to disturbances. Originality/value The results for various scenarios are interesting and show that the controller works quite satisfactorily for all the simulated uncertainties.

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Lee, Jung-Yong, and Younghoon Cho. "Synchronous Reference Frame Repetitive Control of a Single-Phase Three-Level Dual-Buck Photovoltaic Inverter." Electronics 7, no. 10 (October 2, 2018): 226. http://dx.doi.org/10.3390/electronics7100226.

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This paper proposes a synchronous reference frame (SRF) control strategy for a single-phase, three-level, dual-buck photovoltaic (PV) inverter. The concept of virtual d-q transformation is adapted to the current control of the inverter, and the repetitive controller is implemented in the SRF. With the proposed control strategy, the memory allocation quantity for the repetitive controller is decreased and the capability of the current reference tracking is maximized. Thus, the proposed method significantly reduces the total harmonic distortion (THD) of the output current in both the continuous conduction mode (CCM) and the discontinuous conduction mode (DCM). In addition, the distortion of the output current is mostly composed of odd harmonics. Odd harmonic expressed to the even harmonic in SRF can be calculated using Park’s transformation. Therefore, a repetitive controller can improve dynamics by considering only even harmonic components in SRF rather than including all harmonics. The simulation and the experimental results verify the effectiveness of the proposed control strategy. The proposed method not only reduces the THD of the output current in both the CCM operation and the DCM operation, but also improves the dynamics of the current controller.

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Journal articles on the topic 'Discontinuous operation mode'

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