双电源协议

第一篇：双电源协议

双电源（自备电源）安全供用电协议

供电方：XX县供电有限责任公司

用电方：

为明确供电企业（以下简称供电方）和双电源（自备电源）用电客户（以下简称用电方）在电力供应与使用中的权利和义务，安全、合理、有序地供电和用电，根据《电力法》、《电力供应与使用条例》、《供电营业规则》及《农村安全用电规程》等电力法规的规定；经双方协商一致，达成以下协议，共同信守、严格履行。

一、供电方式、安装地点及产权分界

1、供电方从

线

号高压杆或从

线

变台

号低压杆接线向用电方供电。

2、用电方自备电源（自备发电机）容量：

千瓦,安装地点：。

3、供电方与用电方的产权分界点：高压供电在线

号高压杆高压计量箱进线T接点处；低压供电在线

变台

号低压杆

计量电度表进线处；具体接线方式及分界点详见附图《供电接线及产权分界示意图》。

二、供用电设施维护管理责任

1、供用电双方按本协议第一条的产权分界各自负责设备的维护管理。

2、供用电双方各自分管的供电设施，除另有约定外，未经对方同意，不得操作或更动；当遇到危及电网和用电安全，或可能造成人身伤亡、设备损坏，或违约用电、窃电、欠费时；供电方可根据实际情况更动或操作用电方的供电设备。

3、在用电方受电装置内安装的用电计量装置及电力负荷管理装置由供电方维护管理，用电方负责保护并监视其正常运行；如有异常，用电方应及时通知供电方。

4、在供电设施上发生的事故引起的法律责任，按《供电营业规则》第五十一条规定处理。

三、安全运行管理责任

1、供电方应当按照双方《供用电合同》的约定，持续地向用电方提供合格的电源。

2、用电方的低压两相自备电源应采用双投刀闸切换电源，用电方的低压三相四线自备电源应采用低压四极双接刀闸，如因条件限制（距离过远或总屏刀闸容量在1000安以上时），可采用电气闭锁，但切换电源时，不允许有合环和并列的可能。

3、用电方的高压自备电源，电源侧的断路器，应尽量采用机械联锁装置，如开关柜距离过远，可采用电气闭锁，但应保证任何情况下，只有一路电源投入运行，而无误并列、误合环的可能；在进户终端杆装置隔离刀闸，该刀闸操作权属供电方。

4、供用电方双电源投入运行时，必须先做核相检查以防非同相并列；用电方在架空线路或电缆线路上从事有可能导致相位变化的工作、配电室（箱）主接线发生变化、主变压器更换或大修后在重新投运时也必须作核相工作。

5、用电方不允许高低压双电源并列运行者，必须在电源开关或刀闸上装设可靠的联锁装置。

6、用电方不得擅自变更主备电源运行方式；不得超过批准的备用用电容量用电。

7、凡经供电方同意二条高压馈线分别同时供电的用电方，其低压侧应各自分开线路供电，严禁合环运行；同时严禁低压侧使用临时线作为互为备用电源。

8、用电方自备电源不得并入电网运行（自备电厂除外），如需同时使用供电方电源及自备电源时，电气结线应各自分开，不得并接，以保证用户负荷权取一个电源。

9、用电方电气值班人员，必须熟悉“双电源管理办法”的要求及调度协议内容、设备调度权限的划分、运行方式的有关规定，必须制定并严格执行现场倒闸操作规程。

10、用电方必须向供电方的调度部门和用电检查部门报送变（配）电值班人员名单；如值班人员有变动时，必须书面通知供电方的调度部门和用电检查部门。

11、用电方不得并列低压双路电源；用户有自备发电机者，其自备电源与电网连接处必须装设双投刀闸，不得使用电气闭锁。

12、用电方装设的自备发电机必须经供电方审核批准后方可投入运行，对未经审批私自投运自备发电机者，一经发现用电检查部门可责成其立即拆除接引线并按《供电营业规则》第100条第6款进行处理。

13、未经供电方用电检查人员同意，用电方不得改变自备发电机与供电系统的一、二次接线，不得向其他用户供电。

14、供电方用电检查部门对装有非并网自备发电机并持有《自备发电机使用许可证》的用户应单独建立台帐进行管理。

15、供电方和用电方分管的供电设施，除另有约定外，未经对方同意，不得操作或更动；如遇紧急情况（如危及电网和用电安全，或可能造成人身伤亡、设备损坏）而必须操作，事后应立即通知对方。

16、在电力供应暂时紧张时，或个别用户确因生产需要安装自备发电机组的，均按本规定办理；但电网供电正常后应立即拆除，改为单电源用电。

四、约定事项及违约责任

1、供电方对用电方自备电源的运行使用情况有权进行检查，对安全存在的隐患提出书面整改意见；用电方整改后，应及时进行验收。供电方不承担因用电方电气设备不合格引起的任何责任。

2、用电方对其所有的自备电源应定期进行检查、检修和试验，对可能危及受电线路廊道的树木、竹子及时进行修剪或砍伐，消除设备隐患，预防电气设备事故和误动作发生。

3、用电方未依照约定履行维护检查的义务，导致自备电源设备（含保护设施）带病运行，存在安全隐患的，供电方有权对用电方直接停止供电。

4、用电方误操作或其设备缺陷，使自备电源电力向供电方电网送电导致的一切后果全部由用电方承担。

5、用电方自备电源只能作为停电时的应急措施，自发自供，不得将自备电源的电力向自身以外供电；未经供电方同意，擅自供出电源的，按《供电营业规则》相关条款规定处理。

6、用电方未执行本协议或有关规定、管理不到位，给供电方或社会带来人身、设备损害，用电方必须承担全部法律责任。

五、争议的解决方式

供用双电方因履行本协议发生争议时应依本协议之原则协商解决；协商不成时，双方共同提请电力管理部门行政调解；调解不成时，双方可提起诉讼解决。

六、本协议效力及未尽事宜

1、本协议未尽事宜，按《电力法》、《电力供应与使用条例》、《供电营业规则》等有关法律、法规的规定办理；如遇国家法律、政策调整时，应按相应规定修改、补充本合同有关条款。

2、本协议有效期自

****年**月**日起至

****年**月**日止。协议到期后，如供用电双方均未提出变更、解除协议，本协议继续有效。

3、供电方、用电方任何一方欲修改、变更、解除协议时，按《供电营业规则》第94条办理；在修改、变更、解除协议的书面协议签定前，本协议继续有效。

4、本协议自供电方、用电方签字，并加盖公章后生效。

5、本协议正本一式

份。供电方、用电方各执

份。

6、本协议附件包括：

(1)、供用电接线及产权分界示意图 ；

(2)、双电源（自备电源）设备台帐表；

(3)、上述附件为本协议不可分割的组成部分。

七、双方签字：

供电方：（签章）

用电方：（签章）

法定代表（负责）人： 或其委托代理人：

地址：

联系电话：

签订时间：

年

月

法定代表（负责）人：

或其委托代理人：

地址：

联系电话：

签订时间：

****年**月**日 日

第二篇：双电源实验报告写作要求

实验报告写作按以下几方面要求完成，用A4的山东建筑大

学实验报告

山东建筑大学实验报告

学院：------------班级：-------------姓名：------------学号：-------------课程：------------实验日期：-----------年----月-----日成绩：-------------

实验1双电源互为备用实验

一、实验目的二、实验器材

三、实验内容

1、双电源互为备用实验

2、双电源互为备用实验线路图

四、实验步骤及实验结果记录

五、实验结果分析

注意：实验报告内容手写（实验线路图要手绘），请不要打印。

第三篇：用户双电源(自备电源)管理办法

用户双电源(自备电源)管理办法

为了加强用电管理，确保供用电双方的安全生产，防止双电源倒送电造成人身、设备事故，特制定本管理办法。

1、凡一个用户的同一供电点，由两路及以上不同电源供电或是由我公司一路电源供电，另一路由用户自备电源（包括逆变电源）者，均属双电源用户。

2、装设双电源用户的条件是：突然停电或间断供电，会严重威胁人身及设备安全和有重大政治影响，或造成生产和财产重大损失。

3、凡需装设双电源用户，应事先向电力公司营业所提出书面申请（内容包括：申请理由、现有供用电状况，申请备用或保安电源的容量。自备发电机组装置容量和台数、变配电室双电源一次主结线设计图、防止倒送电及防误并列的措施等），电力公司应严格审核，严加控制。经审查后，答复用户。

4、双电源用户均应签订《双电源（自备电源）供用电协议书》后，方可投入运行。对未曾申请或虽已申请（且已安装好），但未经我公司正式批准而擅自使用双电源者，一经发现，则予停止供电，并按违章用电论处。

5、任何用户（包括双电源用户），都无权私自转供给其他单位或个人；任何单位或个人都不得私拉乱接，改变原来供电电源的接线，而构成双电源。

6、未经办理正式手续，电力公司任何部门或个人均无权私自许可任何单位或个人接用双电源，也无权私自改接线路而使之成为双电源，否则，一经发现，予以严肃处理。

7、为确保供用电双方人身及设备安全，防止倒送电和误并列，特对双电源切换装置规定如下：

7.1常用、备用电源切换装置应安装于同一配电室内。

7.2低压双电源应采用双投刀闸切换电源，低压三相四线供电用户，应采用低压四极双接刀闸，如因条件限制（距离过远或总屏刀闸容量在1000安以上时），可采用电气闭锁，但切换电源时，不允许有合环和并列的可能。

7.3高压双电源供电的用户，电源侧的断路器，应尽量采用机械联锁装置，如开关柜距离过远，可采用电气闭锁，但应保证任何情况下，只有一路电源投入运行，而无误并列、误合环的可能。在进户终端杆装置隔离刀闸，该刀闸操作权属电力公司。

8、高压双电源用户，其切换电源不论室内外操作，应事先向电力公司调度室内提出申请（书面或电话），经同意后方可切换，切换时用户应执行倒闸操作票和监护制度。切换完毕，应向调度报告。高压开关、刀闸均应按规定统一编号，以便填写倒闸操作票。如发生事故紧急情况，用户应先切断电原供电电源后再进行转电操作，并及时报告我公司调度所。具体应按电网调度规程和《供用电合同》有关规定进行操作

9、凡经电力公司同意二条高压馈线分别同时供电的用户，其低压侧应各自分开线路供电，严禁合环运行。同时严禁低压侧使用临时线作为互为备用电源。

10、自备电源不得并入电网运行（自备电厂除外），如需同时使用电力公司电源及自备电源时，电气结线应各自分开，不得并接，以保证用户负荷权取一个电源。

11、双电源用户如需变更双电源供电范围、容量、接线方式时，应事先向电力公司提出书面申请，经电力公司审查同意后方可变动。投入前经检查合格，并重新修订《双电源（自备电源）供用电协议书》后，方准许其投入运行。

12、在电力供应暂时紧张时，或个别用户确因生产需要安装自备发电机组的，均按本规定办理。但电网供电正常后应立即拆除，改为单电源用电。

13、双电源用户应严格遵守《双电源（自备电源）供用电协议书》规定，本规定未尽事宜，均按《供电营业规则》或国家颁布的有关法规指令办理，或由双方协商后换文作为《协议书》附件。

14、本规定自公布之日起执行，凡违反本规定者，按违章用电处理。如发生事故，由违章者负责承担一切后果，并追究责任；情节严重时，报请上级机关和司法部门予以惩处。

15、双电源用户的申报、审批、检验、异动、协议签订等工作由电力公司营销部归口负责受理，然后转生计部、调度室会审无异议后，将《双电源（自备电源）供用电协议书》作为《供用电合同》之附件。

16、双电源用户设备管理维护按产权分界点划分，用户设备监督由营销部、用电检查部负责，调度操作权归由调度人员统一调度。

第四篇：煤矿供电及“双回路、双电源”规定

煤矿供电及“双回路、双电源”的相关规定

1、矿井地面变电所、配电所的高压及低压母线应采用单母线分段接线，以保证供电连续性。高压母线亦可采用分段单母线带旁路母线或双母线的接线。

2、矿井应有两回路电源线路。当任一回路发生故障停止供电时，另一回路应能担负矿井全部负荷。年产60000t以下的矿井采用单回路供电时，必须有备用电源；备用电源的容量必须满足通风、排水、提升等的要求。

矿井的两回路电源线路上都不得分接任何负荷。

正常情况下，矿井电源应采用分列运行方式，一回路运行时另一回路必须带电备用，以保证供电的连续性。

10kV及其以下的矿井架空电源线路不得共杆架设。

矿井电源线路上严禁装设负荷定量器。

3、对井下各水平中央变（配）电所、主排水泵房和下山开采的采区排水泵房供电的线路，不得少于两回路。当任一回路停止供电时，其余回路应能担负全部负荷。

3、主要通风机、提升人员的立井绞车、抽放瓦斯泵等主要设备房，应各有两回路直接由变（配）电所馈出的供电线路；受条件限制时，其中的一回路可引自上述同种设备房的配电装置。

本条上述供电线路应来自各自的变压器和母线段，线路上不应分接任何负荷。

本条上述设备的控制回路和辅助设备，必须有与主要设备同等可靠的备用电源。

4、下列用电设备应按一级用电负荷供电，其配电装置必须由两回路或两回路以上电源线路供电。电源线路应引自不同的变压器和母线段，且线路上不应分接任何其他负荷。

1）井下主排水泵：

2）下山采区排水泵：

3）兼作矿井主排水泵的井下煤水泵：

4）经常升降人员的暗副立井绞车；

5）井下移动式瓦斯抽放泵站。

5、下列用电设备应按二级用电负荷供电，其配电装置宜由两回电源线路供电，并宜引自不同的变压器和母线段。当条件受限制时，其中一回电源线路可引自本条规定的同种设备的配电点处。

1）暗主井提升设备、主井装载设备、大巷强力带式输送机、主运输用的井下电机车充电及整流设备；

2）经常升降人员的暗副斜井提升设备、副井井底操车设备、无轨运输换装设备；

3）供综合机械化采煤的采区变(配)电所；

4）煤与瓦斯突出矿井的采区变(配)电所；

5）井下移动式制氮机；

6）井下集中制冷站；

7）不兼作矿井主排水泵的井下煤水泵、井底水窝水泵；

8）井下运输信号系统；

9）井下安全监控系统分站。

6、井下主(中央)变电所应由矿井地面主变(配)电所直接供电。电源电缆不应少于两回路，并应引自地面变电所的不同母线段，且当任一回路停止供电时，其余回路的供电能力应能承担其供电范围内全部负荷的用电要求。

7、采区变(配)电所宜由井下主(中央)变电所或附近地面变电所供电。由地面变电所供电时，电缆可由进风井或钻口下井。

8、煤(岩)与瓦斯(二氧化碳)突出矿井的采区、下山采区、高产高效和综合机械化开采的采(盘)区供电时，电源电缆不应少于两个回路，且当任一回路停止供电时，其余回路的供电能力应能承担该采(盘)区负荷的用电要求。

9、井下局部通风机供配电，必须遵守下列规定：

1）低瓦斯矿井掘进工作面局部通风机应采用装有选择性漏电保护的专用开关和专用线路供电：

2）高瓦斯矿井掘进工作面局部通风机应采用专用变压器、专用开关和专用线路的“三专”供电：

3）煤(岩)与瓦斯(二氧化碳)突出矿井、瓦斯喷出区域、掘进工作面的局部通风机应采用双电源供电。其中，主供电源应采用“三专”供电，备供电源允许引自其他动力变压器的低压母线段。但其供电回路应采用装有选择性漏电保护的专用开关和专用线路供电；

4）使用局部通风机供风的地点，其配电设备必须实行风电和瓦斯电闭锁，保证在停风和瓦斯超限后能切断该区域内全部非本质安全型电气设备的电源。

10、井下主(中央)变电所内的动力变压器不应少于2台，当1台停止运行时，其余变压器应能保证一、二级负荷用电。

11、主(中央)变电所高压母线接线及运行方式，宜与相对应的地面变电所母线接线及运行方式相适应。高压母线应采用单母线分段接线方式，并应设置分段联络开关，正常情况下分列运行，且高压母线分段数应与下井电缆回路数相协调。

12、各类高压负荷宜均衡地分接于各段母线上，但同一用电设备的多台驱动电机应接在同一段母线上。

13、当主排水泵为低压负荷且由井下主(中央)变电所供电时，井下主(中央)变电所应符合下列规定：

1）主变电所的变压器台数应不应少于2台，；

2）低压母线应采用单母线分段接线方式，并应设置分段联络开关，正常情况下分列运行。

14、主(中央)变电所内设备之间的电气连接，联台设备间应采用母线连接，其余设备间宜采用电缆连接。

15、单电源进线的采区变电所，当变压器不超过2台且无高压出线时，可不设置电源进线开关。当变压器超过2台或有高压出线时，应设置进线开关。

16、双电源进线的采区变电所，应设置电源进线开关。当其正常为一回路供电、另一回路备用时，母线可不分段；当两回路电源同时供电时，母线应分段并设联络开关，正常情况下应分列运行。

17、由井下主(中央)变电所向采区供电的单回电缆供电线路上串接的采区变电所数不应超过3个。

18、移动变电站

1）下列情况宜采用移动变电站供电：

（1）综采、连采及综掘工作面的供电；

（2）由采区固定变电所供电困难或不经济时；

（3）独头大巷掘进、附近无变电所可利用时。

2）向回采工作面供电的移动变电站及设备列车宜布置在进风巷内，且距工作面的距离宜为100至150m。

3）由采区变电所向移动变电站供电的单回电缆供电线路上，串接的移动变电站数不宜超过3个。不同工作面的移动变电站不应共用电源电缆。

19、供电电缆

1）1140V设备使用的电缆，应采用带有煤矿矿用产品安全标志的分相屏蔽橡胶绝缘软电缆；

2）660V或380V设备有条件时应使用带有煤矿矿用产品安全标志的分相屏蔽的橡胶绝缘软电缆。固定敷设时可采用铠装聚氯乙烯绝缘铜芯电缆或矿用橡套电缆；

3）移动式和手持式电器设备，应使用专用的矿用橡套电缆；

4）采区低压电缆严禁采用铝芯。

20、严禁由地面中性点直接接地的变压器或发电机直接向井下供电。

第五篇：双电源自动转换控制器英文文献

Modeling, Simulation, and Reduction of Conducted Electromagnetic Interference Due to a PWM Buck Type Switching Power Supply

A.Farhadi

Abstract: Undesired generation of radiated or conducted energy in electrical systems is called Electromagnetic Interference(EMI).High speed switching frequency in power electronics converters especially in switching power supplies improves efficiency but leads to EMI.Different kind of conducted interference, EMI regulations and conducted EMI measurement are introduced in this paper.Compliancy with national or international regulation is called Electromagnetic Compatibility(EMC).Power electronic systems producers must regard EMC.Modeling and simulation is the first step of EMC evaluation.EMI simulation results due to a PWM Buck type switching power supply are presented in this paper.To improve EMC, some techniques are introduced and their effectiveness proved by simulation.Index Terms: Conducted, EMC, EMI, LISN, Switching Supply I.INTRODUCTION

FAST semiconductors make it possible to have high speed and high frequency switching in power electronics 1.High speed switching causes weight and volume reduction of equipment，2but some unwanted effects such as radio frequency interference appeared.Compliance with electromagnetic compatibility(EMC)regulations is necessary for producers to present their products to the markets.It is important to take EMC aspects already in design phase

3.Modeling and simulation is the most effective tool to analyze EMC consideration before developing the products.A lot of the previous studies concerned the low frequency analysis of power electronics components

45.Different types of power electronics converters are capable to be considered as source of EMI.They could propagate the EMI in both radiated and conducted forms.Line Impedance Stabilization Network(LISN)is required for measurement and calculation of conducted interference level the EMC evaluation criterion

6.Interference spectrum at the output of LISN is introduced as.National or international regulations are the references for

7878the evaluation of equipment in point of view of EMC II.SOURCE, PATH AND VICTIM OF EMI

.Undesired voltage or current is called interference and their cause is called interference source.In this paper a high-speed switching power supply is the source of interference.Interference propagated by radiation in area around of an interference source or by conduction through common cabling or wiring connections.In this study conducted emission is considered only.Equipment such as computers, receivers, amplifiers, industrial controllers, etc that are exposed to interference corruption are called victims.The common connections of elements, source lines and cabling provide paths for conducted noise or interference.Electromagnetic conducted interference has two components as differential mode and common mode 9.A.Differential mode conducted interference

This mode is related to the noise that is imposed between different lines of a test circuit by a noise source.Related current path is shown in Fig.1

9.The interference source, path impedances, differential mode current and load impedance are also shown in Fig.1.B.Common mode conducted interference

Common mode noise or interference could appear and impose between the lines, cables or connections and common ground.Any leakage current between load and common ground could be modeled by interference voltage source.Fig.2 demonstrates the common mode interference source, common mode currents IIand the related current paths

9cm1

and cm2

.The power electronics converters perform as noise source between lines of the supply network.In this study differential mode of conducted interference is particularly important and discussion will be continued considering this mode only.III.ELECTROMAGNETIC COMPATIBILITY REGULATIONS

Application of electrical equipment especially static power electronic converters in different equipment is increasing more and more.As mentioned before, power electronics converters are considered as an important source of electromagnetic interference and have corrupting effects on the electric networks 2.High level of pollution resulting from various disturbances reduces the quality of power in electric networks.On the other side some residential, commercial and especially medical consumers are so sensitive to power system disturbances including voltage and frequency variations.The best solution to reduce corruption and improve power quality is complying national or international EMC regulations.CISPR, IEC, FCC and VDE are among the most famous organizations from Europe, USA and Germany who are responsible for determining and publishing the most important EMC regulations.IEC and VDE requirement and limitations on conducted emission are shown in Fig.3 and Fig.4

79.For different groups of consumers different classes of regulations could be complied.Class A for common consumers and class B with more hard limitations for special consumers are separated in Fig.3 and Fig.4.Frequency range of limitation is different for IEC and VDE that are 150 kHz up to 30 MHz and 10 kHz up to 30 MHz respectively.Compliance of regulations is evaluated by comparison of measured or calculated conducted interference level in the mentioned frequency range with the stated requirements in regulations.In united European community compliance of regulation is mandatory and products must have certified label to show covering of requirements 8.IV.ELECTROMAGNETIC CONDUCTED INTERFERENCE MEASUREMENT A.Line Impedance Stabilization Network(LISN)

1-Providing a low impedance path to transfer power from source to power electronics converter and load.2-Providing a low impedance path from interference source, here power electronics converter, to measurement port.Variation of LISN impedance versus frequency with the mentioned topology is presented in Fig.7.LISN has stabilized impedance in the range of conducted EMI measurement

7.Variation of level of signal at the output of LISN versus frequency is the spectrum of interference.The electromagnetic compatibility of a system can be evaluated by comparison of its interference spectrum with the standard limitations.The level of signal at the output of LISN in frequency range 10 kHz up to 30 MHz or 150 kHz up to 30 MHz is criterion of compatibility and should be under the standard limitations.In practical situations, the LISN output is connected to a spectrum analyzer and interference measurement is carried out.But for modeling and simulation purposes, the LISN output spectrum is calculated using appropriate software.V.SIMULATION OF EMI DUE TO A PWM BUCK TYPE SWITCHINGPOWER SUPPLY

For a simple fixed frequency PWM controller that is applied to a Buck DC/DC converter, it is possible to assume the error voltage(v)changes slow with respect to the switching frequency，ethe pulse width and hence the duty cycle can be approximated by(1).Vp is the saw tooth waveform amplitude.A.PWM waveform spectral analysis

The normalized pulse train m(t)of Fig.8 represents PWM switch current waveform.The nth pulse of PWM waveform consists of a fixed component D/fs , in which D is the steady state duty cycle, and a variable component dn/f sthat represents the variation of duty cycle due to variation of source, reference and load.As the PWM switch current waveform contains information concerning EMI due to power supply, it is required to do the spectrum analysis of this waveform in the frequency range of EMI studies.It is assumed that error voltage varies around Vwith amplitude of Vas is shown in(2).e

e1

fm represents the frequency of error voltage variation due to the variations of source, reference and load.The interception of the error voltage variation curve and the saw tooth waveform with switching frequency, leads to(3)for the computation of duty cycle coefficients10.Maximum variation of pulse width around its steady state value of D is limited to D1.In each period of Tm=1/fm , there will be r=fs/fm pulses with duty cycles of dn.Equation(4)presents the Fourier series coefficients Cn of the PWM waveform m(t).Which have the frequency spectrum of Fig.9.B-Equivalent noise circuit and EMI spectral analysis

To attain the equivalent circuit of Fig.6 the voltage source Vs is replaced by short circuit and converter is replaced by PWM waveform switch current(I)as it has shown in Fig.10.ex

The transfer function is defined as the ratio of the LISN output voltage to the EMI current source as in(5).The coefficients di, ni(i = 1, 2, … , 4)correspond to the parameters of the equivalent circuit.Rc and Lc are respectively the effective series resistance(ESR)and inductance(ESL)of the filter capacitor Cf that model the non-ideality of this element.The LISN and filter parameters are as follows: CN = 100 nF, r = 5 Ω, l = 50 uH, RN =50 Ω, LN=250 uH, Lf = 0, Cf =0, Rc= 0, Lc= 0, fs =25 kHz

The EMI spectrum is derived by multiplication of the transfer function and the source noise spectrum.Simulation results are shown in Fig.11.VI.PARAMETERS AFFECTION ON EMI A.Duty Cycle

The pulse width in PWM waveform varies around a steady state D=0.5.The output noise spectrum was simulated with values of D=0.25 and 0.75 that are shown in Fig.12 and Fig.13.Even harmonics are increased and odd ones are decreased that is desired in point of view of EMC.On the other hand the noise energy is distributed over a wider range of frequency and the level of EMI decreased 11.B.Amplitude of duty cycle variation

The maximum pulse width variation is determined by D.The EMI spectrum was simulated

1with D=0.05.Simulations are repeated with D=0.01 and 0.25 and the results are shown in Fig.14 1

1and Fig.15.Increasing of D1 leads to frequency modulation of the EMI signal and reduction in level of conducted EMI.Zooming of Fig.15 around 7component of switching frequency in Fig.16 shows the frequency modulation clearly.th

C.Error voltage frequency

The main factor in the variation of duty cycle is the variation of source voltage.The fm=100 Hz ripple in source voltage is the inevitable consequence of the usage of rectifiers.The simulation is repeated in the frequency of fm=5000 Hz.It is shown in Fig.17 that at a higher frequency for fm the noise spectrum expands in frequency domain and causes smaller level of conducted EMI.On the other hand it is desired to inject a high frequency signal to the reference voltage intentionally.D.Simultaneous effect of parameters

Simulation results of simultaneous application of D=0.75, D=0.25 and f=5000 Hz that lead

mto expansion of EMI spectrum over a wider frequencies and considerable reduction in EMI level is shown in Fig.18.VII.CONCLUSION

Appearance of Electromagnetic Interference due to the fast switching semiconductor devices performance in power electronics converters is introduced in this paper.Radiated and conducted interference are two types of Electromagnetic Interference where conducted type is studied in this paper.Compatibility regulations and conducted interference measurement were explained.LISN as an important part of measuring process besides its topology, parameters and impedance were described.EMI spectrum due to a PWM Buck type DC/DC converter was considered and simulated.It is necessary to present mechanisms to reduce the level of Electromagnetic interference.It shown that EMI due to a PWM Buck type switching power supply could be reduced by controlling parameters such as duty cycle, duty cycle variation and reference voltage frequency.VIII.REFRENCES

[1] Mohan, Undeland, and Robbins, “Power Electronics Converters, Applications and Design” 3rd edition, John Wiley & Sons, 2003.[2] P.Moy, “EMC Related Issues for Power Electronics”, IEEE, Automotive Power Electronics, 1989, 28-29 Aug.1989 pp.46 – 53.[3] M.J.Nave, “Prediction of Conducted Interference in Switched Mode Power Supplies”, Session 3B, IEEE International Symp.on EMC, 1986.[4] Henderson, R.D.and Rose, P.J., “Harmonics and their Effects on Power Quality and Transformers”, IEEE Trans.On Ind.App., 1994, pp.528-532.[5] I.Kasikci, “A New Method for Power Factor Correction and Harmonic Elimination in Power System”, Proceedings of IEEE Ninth International Conference on Harmonics and Quality of Power, Volume 3, pp.810 – 815, Oct.2000.[6] M.J.Nave, “Line Impedance Stabilization Networks: Theory and Applications”, RFI/EMI Corner, April 1985, pp.54-56.[7] T.Williams, “EMC for Product Designers” 3edition 2001 Newnes.[8] B.Keisier, “Principles of Electromagnetic Compatibility”, 3edition ARTECH HOUSE 1987.[9] J.C.Fluke, “Controlling Conducted Emission by Design”, Vanhostrand Reinhold 1991.[10] M.Daniel,”DC/DC Switching Regulator Analysis”, McGrawhill 1988

[11] M.J.Nave,” The Effect of Duty Cycle on SMPS Common Mode Emission: theory and experiment”, IEEE National Symposium on Electromagnetic Compatibility, Page(s): 211-216, 23-25 May 1989.rd

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