19,162 research outputs found

    Comparison between flying capacitor and modular multilevel inverter

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    The paper describes the operational principle of flying capacitor and modular multilevel inverters. The detailed discussions of dc link capacitors voltage balancing methods for both inverters are given in order to enable fair comparison. The causes of dc link capacitors voltage imbalance in flying capacitor multilevel inverter with more than three levels are highlighted. Computer simulation is used to compare the performance of both inverters under several operating conditions

    A holistic DC link architecture design method for multiphase Integrated Modular Motor Drives

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    This article describes a holistic DC link architecture design method that considers the end-application of the drive and its corresponding constraints e.g. the maximum battery ripple current for a battery-supplied inverter. Also, the levers that are available to comply with the design criteria are presented e.g. the use of interleaved carrier waves. This holistic approach will result in a feasible and performant Integrated Modular Motor Drive from an application point of view. Finally, a platform is presented that was developed for feasibility and performance assessment of various DC link architectures obtained from the holistic design approach. The platform comprises a fifteen phase integrable modular motor drive for an Axial Flux Permanent Magnet Synchronous Machine. It allows non-intrusive reconfiguration of the DC link architecture and implementation of various control strategies and interleaved PWM schemes

    DC-link approach to constant-frequency aircraft power

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    This paper discusses a hybrid high-power aircraft electrical system that has very difficult and complex operating requirements. Many issues raised in selecting an approach for this application are similar to those that must eventually be addressed for a large all-electric aircraft. The requirements for this specific system are reviewed, a solution for those requirements is proposed, and some explanation is provided for the choice. Because the system requires a substantial amount of 400-Hz power, a dc-link system was selected to provide that power

    Perancangan Kontroler DC Link Inverter Sisi Jala-jala Pada Kondisi Faktor Daya 1 Untuk Pembangkit Listrik Tenaga Bayu 100kW

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    Sistem kontrol pembangkit listrik tenaga bayu (PLTBayu) 100kW yang sedang dirancang bangun di Pusat Penelitian Tenaga Listrik dan Mekatronik (Puslit Telimek) LIPI memakai inverter 3 fasa yang dipasang pada sisi jala-jala. Inverter ini berfungsi menyalurkan daya listrik yang dibangkitkan oleh generator induksi 3 fasa dari DC link saat operasi dan menyalurkan daya listrik dari jala-jala ke DC link saat start up. Saat melakukan fungsinya inverter ini perlu dikontrol untuk menjaga tegangan DC link pada kisaran nilai yang diinginkan. Makalah ini bertujuan untuk merancang kontroler tegangan DC link untuk inverter sisi jala-jala. Kontrol dc link terdiri dari kontrol umpan Balik PI dan kontrol umpan maju dari arus yang masuk dari sisi generator. Pada makalah ini digunakan sinusoidal Pulse Width Modulation (PWM) dengan dan tanpa penambahan sinyal urutan nol (ZSS). Dari hasil simulasi ditarik kesimpulan: (a) kontroler DC link yang telah dirancang mampu mencapai tegangan referensi yang diinginkan, (b) modulasi dengan tambahan sinyal urutan nol memberikan tanggapan tegangan DC link yang lebih baik dari pada modulasi tanpa tambahan sinyal urutan nol, dan (c) modulasi dengan tambahan sinyal urutan nol memberikan faktor daya yang lebih mendekati 1 dari pada modulasi tanpa tambahan sinyal urutan nol

    Perancangan Kontroler DC Link Inverter Sisi Jala-jala pada Kondisi Faktor Daya 1 untuk Pembangkit Listrik Tenaga Bayu 100kW

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    Sistem kontrol pembangkit listrik tenaga bayu (PLTBayu) 100kW yang sedang dirancang bangun di Pusat Penelitian Tenaga Listrik dan Mekatronik (Puslit Telimek) LIPI memakai inverter 3 fasa yang dipasang pada sisi jala-jala. Inverter ini berfungsi menyalurkan daya listrik yang dibangkitkan oleh generator induksi 3 fasa dari DC link saat operasi dan menyalurkan daya listrik dari jala-jala ke DC link saat start up. Saat melakukan fungsinya inverter ini perlu dikontrol untuk  menjaga tegangan DC link pada kisaran nilai yang diinginkan. Makalah ini bertujuan untuk merancang kontroler tegangan DC link untuk inverter sisi jala-jala. Kontrol dc link terdiri dari kontrol umpan balik PI dan kontrol umpan maju dari arus yang masuk dari sisi generator. Pada makalah ini digunakan sinusoidal Pulse Width Modulation (PWM)  dengan dan tanpa penambahan sinyal urutan nol (ZSS). Dari hasil simulasi ditarik kesimpulan: (a) kontroler DC link yang telah dirancang mampu mencapai tegangan referensi yang diinginkan, (b) modulasi dengan tambahan sinyal urutan nol memberikan tanggapan tegangan DC link yang lebih baik dari pada modulasi tanpa tambahan sinyal urutan nol, dan (c) modulasi dengan tambahan sinyal urutan nol memberikan faktor daya yang lebih mendekati 1 dari pada modulasi tanpa tambahan sinyal urutan nol.Kata kunci: tenaga bayu, pembangkit listrik, inverter 3 fasa, kontrol tegangan dc link, kontrol umpan balik, kontrol umpan maju, sinusoidal PWM, ZSS

    A plug-and-play ripple mitigation approach for DC-links in hybrid systems

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    © 2016 IEEE.In this paper, a plug-and-play ripple mitigation technique is proposed. It requires only the sensing of the DC-link voltage and can operate fully independently to remove the low-frequency voltage ripple. The proposed technique is nonintrusive to the existing hardware and enables hot-swap operation without disrupting the normal functionality of the existing power system. It is user-friendly, modular and suitable for plug-and-play operation. The experimental results demonstrate the effectiveness of the ripple-mitigation capability of the proposed device. The DC-link voltage ripple in a 110 W miniature hybrid system comprising an AC/DC converter and two resistive loads is shown to be significantly reduced from 61 V to only 3.3 V. Moreover, it is shown that with the proposed device, the system reliability has been improved by alleviating the components' thermal stresses

    Design Oriented Analysis of Control Loops Interaction in Power Synchronization-based Voltage Source Converter

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    Power synchronization mechanism is coupled with the dc-link, since both synchronization and dc-link dynamics depend on the active power. The active power filter used in the frequency droop is correlated with inertia emulation, which affects the dc-link voltage. Furthermore, the coupling between active and reactive power in the low-voltage grid suggests a possible interaction between dc-link and reactive power control. The strong coupling between all the control loops and the dc-link in power synchronization-based converters represents a challenge both for the stability and for the controller tuning. This paper addresses the tuning of power synchronization-based converter with consideration of all the control loops interactions. A complete converter state-space model is derived, and a step-by-step tuning procedure based on eigenvalue analysis is proposed. Experimental results are provided to demonstrate the method

    Frequency Converter - DC Link Optimizing

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    Import 05/08/2014Tato diplomová práce se zabývá popisem, návrhem a optimalizací stejnosměrného meziobvodu napěťového frekvenčního měniče. V praxi používaného pro pohony asynchronních motorů. Na začátku je uvedena problematika, která se týká vlivu zátěže na trojfázovou napájecí síť. Především pak vznik jalového výkonu a harmonického zkreslení. Dále jsou uvedeny různé způsoby korekce účiníku a omezení harmonického zkreslení. Popisy funkce používaných obvodů jsou provedeny pomocí principiálních schémat a základních matematických vztahů pro vyjádření obvodových veličin. Zároveň s rozborem výhod a nevýhod těchto obvodů jsou zakreslena schémata propojení napěťových meziobvodů s trojfázovým můstkovým diodovým usměrňovačem. Dalším bodem je návrh zvyšujícího stejnosměrného měniče ve funkci napěťového meziobvodu. Hodnoty obvodových prvků byly navrženy pomocí simulačního prostředí PSpice (v programu OrCad) a konkrétní hodnoty jsou podloženy výpočty. V poslední části je provedeno měření na komerčním frekvenčním měniči Siemens Sinamics S120, který je připojen k trojfázovému asynchronnímu motoru.This thesis deals with the description, design and optimization of the DC voltage link of the voltage frequency inverter. In practice used for drive of asynchronous motors. At the beginning there is an issue, which concerns the effects of influence of ballast on the three-phase supply mains. Especially the formation of reactive power and harmonic distortion. The following are the different ways of power factor correction then limits of harmonic distortion. Descriptions of function of used circuits are performed by a fundamental schematic diagrams and basic mathematical relations for the expression of peripheral variables. Together with the analysis of the advantages and disadvantages of these circuits are drawn schematic diagrams of linking the intermediate voltage circuits with three phase diode bridge rectifier. The next point is the draft of increasing DC converter which has a function in DC voltage link. The values of the circuit elements were designed using PSpice simulation environment (in OrCAD) and specific values are based on calculations. In the last part is the measurement, which is performed with a commercial frequency inverter Siemens SINAMICS S120, connected to three-phase asynchronous motor.430 - Katedra elektronikydobř

    Reactive Power Limits of Single-Phase and Three-Phase DC-Link VSC STATCOMs under Negative-Sequence Voltage and Current

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    This paper analyzes and compares the reactive power limits of single- and three-phase configured dc-link Voltage Source Converter (VSC) structures for Static Synchronous Compensator (STATCOM) to operate with negative-sequence voltage and current. The three-level Neutral Point Clamped (3L NPC) is used as an example of a three-phase dc-link topology. Likewise, the Cascaded H-Bridge (CHB) is used as a single-phase dc-link case, in both star and delta configurations. Modular Multilevel Converter is also considered as a combination of both dc-link configurations. The conclusions drawn are generic whichever the Power Electronics Building Block (PEBB) used in each VSC structure

    Enhanced control strategy of full-bridge modular multilevel converter

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    This paper describes a control approach that allows the cell capacitor voltages of the full-bridge modular multilevel converter (FB-MMC) to be controlled independent of the input dc link voltage. Moreover, this control approach offers the possibility of operating FB-MMC from bi-polar dc link voltages; thus, creating new possibilities for building generic hybrid dc grids with reversible dc link voltage, where the conventional line commutated current source converters can operate alongside voltage source converters. Furthermore, the presented control approach improves the dc fault ride-through of the FB-MMC compared to existing approaches. This could be achieved by an active control of the arm currents and cell capacitor voltages, and full exploitation of the FB-MMC redundant switch states. Operation of the FB-MMC with reversible DC link voltage and decoupled control of the cell capacitor voltages from the dc link voltage are demonstrated using simulations. The major findings and implications of this work are highlighted
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