Integrated EMI/Thermal Design forSwitching Power SuppliesWei ZhangThesis submitted to the Faculty of theVirginia Polytechnic Institute and State Universityin partial fulfillment of the requirements for the degree of Integrated EMI/Thermal Design forSwitching Power SuppliesWei Zhang(ABSTRACT)This work presents the modeling and analysis of EMI and thermal performancefor switch power supply by using the CAD tools. The methodology and design guidelinesare developed.By using a boost PFC circuit as an example, an equivalent circuit model is builtfor EMI noise prediction and analysis. The parasitic elements of circuit layout andcomponents are extracted analytically or by using CAD tools. Based on the model, circuitlayout and magnetic component design are modified to minimize circuit EMI. EMI filtercan be designed at an early stage without prototype implementation.In the second part, thermal analyses are conducted for the circuit by using thesoftware Flotherm, which includes the mechanism of conduction, convection andradiation. Thermal models are built for the components. Thermal performance of thecircuit and the temperature profile of components are predicted. Improved thermalmanagement and winding arrangement are investigated to reduce temperature.In the third part, several circuit layouts and inductor design examples are checkedfrom both the EMI and thermal point of view. Insightful information is obtained.
標(biāo)簽： EMI 開關(guān)電源 英文
上傳時間： 2013-11-10
上傳用戶：1595690
Power over Ethernet (PoE) is a new development thatallows for the delivery of power to Ethernet-based devicesvia standard Ethernet CAT5 cable, precluding the need forwall adapters or other external power sources. The PoEspecification defines a hardware detection protocol wherePower Sourcing Equipment (PSE) is able to identify PoEPowered Devices (PDs), thus allowing full backwardscompatibility with non-PoE-aware (legacy) Ethernetdevices.
標(biāo)簽： PoE 電池電路 擴(kuò)展 以太網(wǎng)供電
上傳時間： 2013-11-11
上傳用戶：daoyue
Although recent popular attention is focused on LithiumIon batteries, one must not forget that other batterychemistries, such as Nickel Cadmium (NiCd) and NickelMetal Hydride (NiMH) have advantages in rechargeablepower systems. Nickel-based batteries are robust, capableof high discharge rates, have good cycle life, do notrequire special protection circuitry and are less expensivethan Li-Ion. Among the two, NiMH batteries are rapidlyreplacing NiCd because of their higher capacity (40% to50% more) and the environmental concerns of the toxiccadmium contained in NiCd batteries.
上傳時間： 2013-11-04
上傳用戶：qq10538412
As the performance of many handheld devices approachesthat of laptop computers, design complexity also increases.Chief among them is thermal management—how doyou meet increasing performance demands while keepinga compact and small product cool in the user’s hand?For instance, as battery capacities inevitably increase,charge currents will also increase to maintain or improvetheir charge times. Traditional linear regulator-based batterychargers will not be able to meet the charge currentand effi ciency demands necessary to allow a product torun cool. What is needed is a switching-based chargerthat takes just about the same amount of space as a linearsolution—but without the heat.
上傳時間： 2013-11-23
上傳用戶：lu2767
為了改變目前電網(wǎng)現(xiàn)場作業(yè)管理的變電巡檢、變電檢修試驗、輸電線路巡檢檢修等管理系統(tǒng)各自獨立運行，信息不能共享，功能、效率受限，建設(shè)和維護(hù)成本高的現(xiàn)狀，提出了采用B/S+C/S構(gòu)架模式，將各現(xiàn)場作業(yè)管理模塊和生產(chǎn)MIS（管理系統(tǒng)）集成為一體的現(xiàn)場作業(yè)管理系統(tǒng)的設(shè)計方案，做到各子系統(tǒng)和生產(chǎn)MIS軟硬資源共享，做到同一數(shù)據(jù)唯一入口、一處錄入多處使用。各子系統(tǒng)設(shè)備人員等基礎(chǔ)信息來源于生產(chǎn)管理系統(tǒng)，各子系統(tǒng)又是生產(chǎn)管理系統(tǒng)的作業(yè)數(shù)據(jù)、缺陷信息的重要來源。經(jīng)過研究試用成功和推廣應(yīng)用，目前該系統(tǒng)已在江西電網(wǎng)220 kV及以上變電站全面應(yīng)用。 Abstract: In order to improve the status that the substation field inspection system， substation equipments maintenance and testing system， power-line inspection and maintenance system are running independent with each other. They can?蒺t share the resource information which accordingly constrains their functions and efficiency， and their construction and maintenance costs are high. This paper introduces a field standardized work management system based on B/S+C/S mode， integrating all field work management systems based on MIS and share the equipments and employee?蒺s data of MIS，the field work data of the sub systems are the source information of MIS， by which the same single data resouce with one-time input can be utilized in multiple places. After the research and testing， this system is triumphantly using in all 220kV and above substations in Jiangxi grid.
標(biāo)簽： 電網(wǎng) 信息化 管理系統(tǒng)
上傳時間： 2013-11-15
上傳用戶：han_zh
為解決直流逆變交流的問題，有效地利用能源，讓電源輸出最大功率，設(shè)計了高性能的基于IR2101最大功率跟蹤逆變器，并以SPMC75F2413A單片機(jī)作為主控制器。高電壓、高速功率的MOSFET或IGBT驅(qū)動器IR2101采用高度集成的電平轉(zhuǎn)換技術(shù)，同時上管采用外部自舉電容上電，能夠穩(wěn)定高效地驅(qū)動MOS管。該逆變器可以實現(xiàn)DC/AC的轉(zhuǎn)換，最大功率點的跟蹤等功能。實際測試結(jié)果表明，該逆變器系統(tǒng)具有跟蹤能力強(qiáng)，穩(wěn)定性高，反應(yīng)靈敏等特點，該逆變器不僅可應(yīng)用于普通的電源逆變系統(tǒng)，而且可應(yīng)用于光伏并網(wǎng)發(fā)電的逆變系統(tǒng)，具有廣泛的市場前景。 Abstract: To solve the problem of DC-AC inverter， and to utilize solar energy more efficiently， the design of maximum power point tracking inverter based on IR2101 was achieved with a high-performance， which can make the system output power maximum. SPMC75F2413A was adopted as main controller. IR2101 is a high voltage， high speed power MOSFET and IGBT driver. It adopted highly integrated voltage level transforming technology， and an external bootstrap capacitor was used， which could drive MOS tube efficiently and stably. Many functions are achieved in the system， such as DC/AC conversion， maximun power point tracking， etc. The actual test result shows that the inverter system has characteristics of strong tracking ability， high stability and reacting quickly. The design can not only be used in ordinary power inverter system， but also be used in photovoltaic power inverter system. The design has certain marketing prospects
上傳時間： 2013-11-17
上傳用戶：lliuhhui
光伏發(fā)電是未來新能源發(fā)電重要方向之一，而光伏變流器是光伏發(fā)電系統(tǒng)的核心。介紹一種基于微網(wǎng)理念的光伏變流器設(shè)計。以該變流器為核心的光伏發(fā)電系統(tǒng)可以看做一個小型的微網(wǎng)系統(tǒng)。該系統(tǒng)能根據(jù)外部電網(wǎng)情況，工作于并網(wǎng)模式和離網(wǎng)模式。介紹了該系統(tǒng)的各個組成部件的設(shè)計以及變流器主電路部分器件的選型。最后，由實驗樣機(jī)進(jìn)行測試。試驗結(jié)果驗證了電路拓?fù)浣Y(jié)構(gòu)及控制方案的可行性，也說明了系統(tǒng)參數(shù)設(shè)計方法的正確性。 Abstract: Solar Photovoltaic generation is an important direction of new energy power generation in the future，while photovoltaic converter is the core of photovoltaic generation system. This paper deals with a study on photovoltaic inverter based on the concept of microgrid. This paper describes a system whose core component is the photovoltaic inverter，can work on grid-connected mode or run independently according to the external situation. The paper simply describes the main components of the system. At last，the prototype was produced and tested. Test result has proved feasibility of circuit topology structure and controlling scheme and shown correctness of system parameters.Key words: PV inverter； microgrid； off-grid； storage battery
標(biāo)簽： 光伏 變流器 系統(tǒng)設(shè)計
上傳時間： 2014-12-24
上傳用戶：Shaikh
鎖定放大是微弱信號檢測的重要手段。基于相關(guān)檢測理論，利用開關(guān)電容的開關(guān)實現(xiàn)鎖定放大器中乘法器的功能，提出開關(guān)電容和積分器相結(jié)合以實現(xiàn)相關(guān)檢測的方法，并設(shè)計出一種鎖定放大器。該鎖定放大器將微弱信號轉(zhuǎn)化為與之相關(guān)的方波，通過后續(xù)電路得到正比于被測信號的直流電平，為后續(xù)采集處理提供方便。測量數(shù)據(jù)表明鎖定放大器前級可將10-6 A的電流轉(zhuǎn)換為10-1 V的電壓，后級通過帶通濾波器級聯(lián)可將信號放大1×105倍。該方法在降低噪聲的同時，可對微弱信號進(jìn)行放大，線性度較高、穩(wěn)定性較好。 Abstract: Lock-in Amplifying（LIA）is one of important means for weak signal detection. Based on cross-correlation detection theory， switch in the swithched capacitor was used as multiplier of LIA， and a new method of correlation detection was proposed combining swithched capacitor with integrator. A kind of LIA was designed which can convert the weak signal to square-wave， then DC proportional to measured signal was obtained through follow-up conditioning circuit， providing convenience for signal acquisition and processing. The measured data shows that the electric current（10-6 A） can be changed into voltage（10-1 V） by LIA， and the signal is magnified 1×105 times by cascade band-pass filter. The noise is suppressed and the weak signal is amplified. It has the advantages of good linearity and stability.
標(biāo)簽： 開關(guān)電容 鎖定放大器
上傳時間： 2013-11-29
上傳用戶：黑漆漆
The P89LPC912/913/914 are single-chip microcontrollers in low-cost 14-pin packages, based on a high performance processor architecture that executes instructions in two to four clocks, six times the rate of standard 80C51 devices. Many system level functions have been incorporated into the P89LPC912/913/914 in order to reduce component count, board space, and system cost.
上傳時間： 2013-10-12
上傳用戶：司令部正軍級
在理論分析循環(huán)碼編碼和譯碼基本原理的基礎(chǔ)上，提出了基于單片機(jī)系統(tǒng)的(24，16)循環(huán)碼軟件實現(xiàn)編碼、譯碼的方案。仿真結(jié)果表明(24，16)循環(huán)碼能有效地克服來自通訊信道的干擾，保證數(shù)據(jù)通信的可靠及系統(tǒng)的穩(wěn)定，使誤碼率大幅度降低。本論文對(24，16)循環(huán)碼的研究結(jié)果表明，可以有效地降低錯誤概率和提高系統(tǒng)的吞吐量，實現(xiàn)糾錯僅需要在接收端增加有限的存儲空間和計算復(fù)雜度，具有一定的實用價值。 Abstract: Based on analyzing the theory of encoding and decoding of cyclic code， this paper showed the schemes of encoding and decoding of(24，16)cyclic code by the software and based on microcontroller. Simulation results show that using (24，16) cyclic codes can effectively overcome the interference from communication channel， ensure the reliability and stability of data communication systems， and reduce the bit error rate greatly. The results of this paper show that by using the (24，16) cyclic code， the error rate can be reduced and the system throughput can be improved. Meanwhile， the system only needs to enlarge limited storage space and computation the complexity at the receiving end to realize error correction. Thus the (24，16) cyclic code has a practical value.
標(biāo)簽： 24 16 單片機(jī)系統(tǒng) 循環(huán)碼
上傳時間： 2013-11-09
上傳用戶：gaoliangncepu
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