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铁粉心滤波器电感的设计学习

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发表于 2007-12-17 13:37:37 | 显示全部楼层 |阅读模式

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  <p align="center"><strong>铁粉心滤波电感器的设计</strong></p><p class="p1" align="center">DesignofChokeUsingIronPowderCores</p><p class="p1" align="center">石家庄自强腾飞磁性材料经销部黄永富(石家庄050000)</p><blockquote><p class="p1"><strong>摘要</strong>:</p><p class="p1">滤波电感(扼流圈)的设计,须考虑到直流磁化的影响。铁粉心的饱和磁通密度高,直流磁化影响较小,费用也低,是一种理想材料。介绍三种扼流圈的设计方法。</p></blockquote><blockquote><p class="p1"><strong>关键词</strong>:直流磁化饱和磁通密度恒磁导</p></blockquote><blockquote><p class="p1"><strong>Abstract:</strong>Designofchoke,mustconsideringthateffectsfromDCbias&#46;IronpowdercoreshashighRsaturationfluxdensity,lowereffectsfromDCbiasandleastexpense,itistheexcellentchoicefordesignchoke&#46;</p><p class="p1"><strong>Keywords:</strong>DCbiasSaturationfluxdensityConstantpermeance</p></blockquote><p class="p1"><strong>1引言</strong></p><p class="p1">  常见的滤波电感主要有:共模滤波电感、差模滤波电感和整流滤波电感。前两种电感主要用于各种线路滤波器,工作在交流条件。而后一种用来滤除整流后的交流纹波,使整流后的直流部分更加平直。由于它工作在直流条件,不得不考虑直流磁化对电感的影响。</p><p class="p1">以往的电子设备,例如使用电子管的电子设备,整流输出多为高电压小电流,当今采用晶体管和集成电路的电子设备,则多为低电压大电流。由于直流磁化力同电流大小成正比,更须注意直流磁化对电感的影响。这就要求滤波电感必须适应于大电流条件。因此,选择什么样的材料作磁心。如何设计好滤波线圈,减少直流磁化的影响,防止磁芯饱和,不能不成为一个值得重视的问题。</p><p class="p1"><strong>2关于恒磁导或恒电感特性</strong></p><p class="p1">整流滤波电感工作在直流大电流条件,工作电流变化,引起电感值的变化越小越好。就是说要求磁心的直流磁化影响较小,即具有某种恒磁导特性。由于直流磁化的影响,电感趋向于饱和,电感量会随着工作电流增加而减小。根据大家的共识,所谓恒磁导特性,亦可称为恒电感特性,是指电感在一定的直流磁化力范围内其电感量不低于初始电感量的一半。掌握了这个特性,我们可以通过挑选不同的磁心,不同的规格,以达到不同的百分比要求。</p><p class="p1"><strong>3磁心材料的选择</strong></p><p class="p1">制作滤波电感,选用何种磁心材料,除了必须注意防止磁心饱和问题外,还必须考虑到磁心的恒磁导特性。需要指出,有些设计人员往往只注意电感量的指标,选择磁导率高的材料,以减少线圈的匝数,而对于电感额定电流较大时,电感量是否减少,减少到什么程度,会不会达到饱和,考虑较小。这是应该注意避免的。</p><p class="p1">表1列出一些磁心材料的恒磁导特性的比较,供选择时参考。表中所说的恒磁导范围,是指在这个直流磁化力范围内,磁导率不会低于50%。减少直流磁化力相应提高磁导率的百分比。表2为磁导率75的铁粉心,在不同直流磁化力时的磁导率的百分数。</p><p class="p1">表1一些磁心材料和恒磁导特性的比较</p><table border="1"><tbody><tr><th colspan="2"><p class="p1">材料</p></th><th colspan="5"><p class="p1">铁基非晶磁环Bs13000GS</p></th><th colspan="3"><p class="p1">开气隙铁基超微晶磁环</p></th></tr><tr><th colspan="2"><p class="p1">μe</p></th><th><p class="p1">2000</p></th><th><p class="p1">1000</p></th><th><p class="p1">500</p></th><th><p class="p1">180</p></th><th><p class="p1">80</p></th><th><p class="p1">300</p></th><th><p class="p1">180</p></th><th><p class="p1">110</p></th></tr><tr><th rowspan="2"><p class="p1">恒磁导范围</p></th><th><p class="p1">A/m</p></th><th><p class="p1">400</p></th><th><p class="p1">800</p></th><th><p class="p1">1600</p></th><th><p class="p1">4000</p></th><th><p class="p1">8000</p></th><th><p class="p1">2400</p></th><th><p class="p1">4000</p></th><th><p class="p1">6400</p></th></tr><tr><th><p class="p1">Oe</p></th><th><p class="p1">5</p></th><th><p class="p1">10</p></th><th><p class="p1">20</p></th><th><p class="p1">50</p></th><th><p class="p1">100</p></th><th><p class="p1">30</p></th><th><p class="p1">50</p></th><th><p class="p1">80</p></th></tr><tr><th colspan="2"><p class="p1">材料</p></th><th colspan="4"><p class="p1">铁镍钼粉心磁环Bs8000GS</p></th><th colspan="4"><p class="p1">铁镍钼粉心磁环Bs&gt;10000GS</p></th></tr><tr><th colspan="2"><p class="p1">μe</p></th><th><p class="p1">60</p></th><th><p class="p1">125</p></th><th><p class="p1">160</p></th><th><p class="p1">300</p></th><th><p class="p1">22</p></th><th><p class="p1">35</p></th><th><p class="p1">60</p></th><th><p class="p1">75</p></th></tr><tr><th rowspan="2"><p class="p1">恒磁导范围</p></th><th><p class="p1">A/m</p></th><th><p class="p1">8000</p></th><th><p class="p1">4000</p></th><th><p class="p1">3200</p></th><th><p class="p1">1600</p></th><th><p class="p1">22400</p></th><th><p class="p1">20000</p></th><th><p class="p1">5600</p></th><th><p class="p1">4000</p></th></tr><tr><th><p class="p1">Oe</p></th><th><p class="p1">100</p></th><th><p class="p1">50</p></th><th><p class="p1">40</p></th><th><p class="p1">20</p></th><th><p class="p1">280</p></th><th><p class="p1">250</p></th><th><p class="p1">70</p></th><th><p class="p1">50</p></th></tr></tbody></table><p class="p1">表2磁导率75的铁粉心不同直流磁化力时的磁导率的百分数*</p><table border="1"><tbody><tr><th><p class="p1"> </p></th><th><p class="p1">0</p></th><th><p class="p1">1</p></th><th><p class="p1">2</p></th><th><p class="p1">3</p></th><th><p class="p1">4</p></th><th><p class="p1">5</p></th><th><p class="p1">6</p></th><th><p class="p1">7</p></th><th><p class="p1">8</p></th><th><p class="p1">9</p></th></tr><tr><th><p class="p1">00</p></th><th><p class="p1">——</p></th><th><p class="p1">100&#46;0</p></th><th><p class="p1">99&#46;9</p></th><th><p class="p1">99&#46;4</p></th><th><p class="p1">98&#46;8</p></th><th><p class="p1">98&#46;2</p></th><th><p class="p1">97&#46;5</p></th><th><p class="p1">96&#46;7</p></th><th><p class="p1">95&#46;7</p></th><th><p class="p1">94&#46;7</p></th></tr><tr><th><p class="p1">10</p></th><th><p class="p1">93&#46;7</p></th><th><p class="p1">92&#46;6</p></th><th><p class="p1">91&#46;4</p></th><th><p class="p1">90&#46;3</p></th><th><p class="p1">89&#46;1</p></th><th><p class="p1">87&#46;9</p></th><th><p class="p1">86&#46;6</p></th><th><p class="p1">85&#46;4</p></th><th><p class="p1">84&#46;1</p></th><th><p class="p1">82&#46;8</p></th></tr><tr><th><p class="p1">20</p></th><th><p class="p1">81&#46;6</p></th><th><p class="p1">80&#46;3</p></th><th><p class="p1">79&#46;0</p></th><th><p class="p1">77&#46;8</p></th><th><p class="p1">76&#46;6</p></th><th><p class="p1">75&#46;4</p></th><th><p class="p1">74&#46;2</p></th><th><p class="p1">73&#46;0</p></th><th><p class="p1">71&#46;8</p></th><th><p class="p1">70&#46;7</p></th></tr><tr><th><p class="p1">30</p></th><th><p class="p1">69&#46;6</p></th><th><p class="p1">68&#46;5</p></th><th><p class="p1">67&#46;4</p></th><th><p class="p1">66&#46;4</p></th><th><p class="p1">65&#46;4</p></th><th><p class="p1">64&#46;4</p></th><th><p class="p1">63&#46;4</p></th><th><p class="p1">62&#46;4</p></th><th><p class="p1">61&#46;5</p></th><th><p class="p1">60&#46;6</p></th></tr><tr><th><p class="p1">40</p></th><th><p class="p1">59&#46;7</p></th><th><p class="p1">58&#46;8</p></th><th><p class="p1">58&#46;0</p></th><th><p class="p1">57&#46;2</p></th><th><p class="p1">56&#46;4</p></th><th><p class="p1">55&#46;6</p></th><th><p class="p1">54&#46;8</p></th><th><p class="p1">54&#46;1</p></th><th><p class="p1">53&#46;3</p></th><th><p class="p1">52&#46;6</p></th></tr><tr><th><p class="p1">50</p></th><th><p class="p1">52&#46;0</p></th><th><p class="p1">51&#46;3</p></th><th><p class="p1">50&#46;6</p></th><th><p class="p1">50&#46;0</p></th><th><p class="p1">49&#46;4</p></th><th><p class="p1">48&#46;8</p></th><th><p class="p1">48&#46;2</p></th><th><p class="p1">47&#46;6</p></th><th><p class="p1">47&#46;0</p></th><th><p class="p1">46&#46;5</p></th></tr></tbody></table><p class="p1">H%*注:纵、横数字相加代表直流磁化力H,其交点对应磁导率的百分数</p><p class="p1"><strong>4有关计算公式</strong></p><p class="p1">表3铁粉心(材料26)特性参数表</p><p class="p1">AL(nH/N2)So(mm2)</p><p class="p1">  为了更好地进行电感设计,满足恒磁要求,需要熟练掌握一些磁学公式,并了解一些必要的磁学知识。</p><p class="p1">上面提到的直流磁化力可以通过(1)进行计算:</p><p class="p1">H=0&#46;4πNI/lOe(1)</p><p class="p1">或H=NI/lA/cm(1′)</p><p class="p1">这里N为线圈匝数;I为电流,单位为安倍(A);l为磁心的平均磁路长度,单位为厘米(cm)。将上述公式进行一下变换,则有:</p><p class="p1">H/NI=0&#46;4π/l或H/NI=1/l</p><p class="p1">对于一个环形磁心(滤波电感不少是采用环形磁心的),由于</p><p class="p1">l=[(D+d)/2]×πcm</p><p class="p1">其中D为外径,d为内径,单位厘米(cm)。</p><p class="p1">因此,H/NI又可由以下方法求得,即</p><p class="p1">H/NI=0&#46;8/(D+d)或H/NI=1/(D+d)0&#46;5π</p><p class="p1">对于任何一个规格的环形磁心,都可得到一个H/NI值,将此值乘以安匝数,就是直流磁化力,即:</p><p class="p1">H=(H/NI)NIOe(或A/cm)</p><p class="p1">由此可以看出,H/NI同l或(D+d)成反比。尺寸大的磁心H/NI值就小,当安匝数一定时,选用大尺寸的磁心,H值就小,恒磁导特性就好。亦可以说,在H值确定的条件下,大尺寸的磁心就有较大的安匝数。</p><p class="p1">以下再列出几个公式:</p><p class="p1">L=N2AL(nH/N2)nH(2)</p><p class="p1">N=[L(nH)/AL(nH/N2)]1/2匝(3)</p><p class="p1">AL=L(nH)/N2nH/N2(4)</p><p class="p1">W(energy)=LI2/2J或Ws(5)</p><p class="p1">此公式中L单位为H,I单位为A。</p><p class="p1">当L单位为μH时,则W为μJ或μWs,将公式(2)代入(6),又可得一关系式:</p><p class="p1">W=LI2/2=N2ALI2/2=(NI)2AL/2(6)</p><p class="p1">此式中,如AL取nH/N2值,则为nJ。为使得出的结果为μJ,则公式可变成:</p><p class="p1">W=(NI)2AL/2000μJ(6′)</p><p class="p1"><strong>5设计方法与步骤</strong></p><p class="p1">&nbsp;&nbsp;&nbsp; 熟悉了上述公式,尚需有磁心生产单位提供的直流叠加特性曲线,就可以进行设计了,图1为美国微金属公司提供的曲线,供设计参考,实际操作时,亦可根据表2提供的数据进行设计计算。</p><p class="p1" align="center">图1美国微金属公司提供的直流叠加特性曲线</p><p class="p1">&nbsp;&nbsp;&nbsp; 由于铁粉心具有饱和磁通密度高,恒磁导特性好,价格便宜,而得到了广泛应用。因此,本文的设计方法与步骤,均以铁粉心为准。其它材料只要改变特性参数,其余无多大差别。</p><p class="p1">&nbsp;&nbsp;&nbsp; 设计依据:电感量为100μH,额定电流为3A,在额定电流时,电感值不得不小于75μH。即要求恒磁导特性为75%。</p><p class="p1">介绍三种设计方法:</p><p class="p1">&nbsp;&nbsp;&nbsp; (1)方法一:利用恒磁导特性曲线及系列产品特性表(表3)进行设计。</p><p class="p1">表3&nbsp; 铁粉心(材料26)特性参数表</p><table border="1"><tbody><tr><th><p class="p1">No</p></th><th><p class="p1">OD×ID×HT</p></th><th><p class="p1">Ae</p></th><th><p class="p1">le</p></th><th><p class="p1">Ve</p></th><th><p class="p1">AL</p></th><th><p class="p1">H/NI</p></th><th><p class="p1">So</p></th><th><p class="p1">l/N</p></th><th><p class="p1">SA</p></th><th><p class="p1">NI</p></th><th colspan="3"><p class="p1">不同J最大NI</p></th></tr><tr><th><p class="p1">-26</p></th><th><p class="p1">mm×mm×mm</p></th><th><p class="p1">cm2</p></th><th><p class="p1">cm</p></th><th><p class="p1">cm3</p></th><th><p class="p1">nH/N2</p></th><th><p class="p1">0&#46;4π/le</p></th><th><p class="p1">cm2</p></th><th><p class="p1">cm</p></th><th><p class="p1">cm2</p></th><th><p class="p1">70%μo</p></th><th><p class="p1">3A/mm2</p></th><th><p class="p1">4A/mm2</p></th><th><p class="p1">5A/mm2</p></th></tr><tr><th><p class="p1">T50</p></th><th><p class="p1">12&#46;7×7&#46;9×4&#46;83</p></th><th><p class="p1">0&#46;112</p></th><th><p class="p1">3&#46;19</p></th><th><p class="p1">0&#46;358</p></th><th><p class="p1">33</p></th><th><p class="p1">0&#46;3939</p></th><th><p class="p1">0&#46;466</p></th><th><p class="p1">2&#46;01</p></th><th><p class="p1">6&#46;86</p></th><th><p class="p1">70</p></th><th><p class="p1">50</p></th><th><p class="p1">60</p></th><th><p class="p1">70</p></th></tr><tr><th><p class="p1">T50B</p></th><th><p class="p1">12&#46;7×7&#46;9×6&#46;35</p></th><th><p class="p1">0&#46;148</p></th><th><p class="p1">3&#46;19</p></th><th><p class="p1">0&#46;471</p></th><th><p class="p1">43&#46;5</p></th><th><p class="p1">0&#46;3939</p></th><th><p class="p1">0&#46;466</p></th><th><p class="p1">2&#46;32</p></th><th><p class="p1">7&#46;83</p></th><th><p class="p1">70</p></th><th><p class="p1">50</p></th><th><p class="p1">60</p></th><th><p class="p1">70</p></th></tr><tr><th><p class="p1">T60</p></th><th><p class="p1">15&#46;2×8&#46;53×5&#46;94</p></th><th><p class="p1">0&#46;187</p></th><th><p class="p1">3&#46;74</p></th><th><p class="p1">0&#46;699</p></th><th><p class="p1">50</p></th><th><p class="p1">0&#46;336</p></th><th><p class="p1">0&#46;571</p></th><th><p class="p1">2&#46;48</p></th><th><p class="p1">9&#46;84</p></th><th><p class="p1">80</p></th><th><p class="p1">60</p></th><th><p class="p1">80</p></th><th><p class="p1">100</p></th></tr><tr><th><p class="p1">T68</p></th><th><p class="p1">17&#46;5×9&#46;4×4&#46;83</p></th><th><p class="p1">0&#46;179</p></th><th><p class="p1">4&#46;23</p></th><th><p class="p1">0&#46;759</p></th><th><p class="p1">43&#46;5</p></th><th><p class="p1">0&#46;297</p></th><th><p class="p1">0&#46;694</p></th><th><p class="p1">2&#46;47</p></th><th><p class="p1">11&#46;2</p></th><th><p class="p1">90</p></th><th><p class="p1">80</p></th><th><p class="p1">110</p></th><th><p class="p1">130</p></th></tr><tr><th><p class="p1">T80</p></th><th><p class="p1">20&#46;2×12&#46;6×6&#46;35</p></th><th><p class="p1">0&#46;231</p></th><th><p class="p1">5&#46;14</p></th><th><p class="p1">1&#46;19</p></th><th><p class="p1">46</p></th><th><p class="p1">0&#46;2445</p></th><th><p class="p1">1&#46;247</p></th><th><p class="p1">2&#46;80</p></th><th><p class="p1">15&#46;5</p></th><th><p class="p1">120</p></th><th><p class="p1">150</p></th><th><p class="p1">200</p></th><th><p class="p1">250</p></th></tr><tr><th><p class="p1">T80B</p></th><th><p class="p1">20&#46;2×12&#46;6×9&#46;53</p></th><th><p class="p1">0&#46;347</p></th><th><p class="p1">5&#46;14</p></th><th><p class="p1">1&#46;78</p></th><th><p class="p1">71</p></th><th><p class="p1">0&#46;2445</p></th><th><p class="p1">1&#46;247</p></th><th><p class="p1">3&#46;44</p></th><th><p class="p1">18&#46;7</p></th><th><p class="p1">120</p></th><th><p class="p1">150</p></th><th><p class="p1">200</p></th><th><p class="p1">250</p></th></tr><tr><th><p class="p1">T90</p></th><th><p class="p1">22&#46;9×14×9&#46;53</p></th><th><p class="p1">0&#46;395</p></th><th><p class="p1">5&#46;78</p></th><th><p class="p1">2&#46;28</p></th><th><p class="p1">70</p></th><th><p class="p1">0&#46;2174</p></th><th><p class="p1">1&#46;539</p></th><th><p class="p1">3&#46;64</p></th><th><p class="p1">22&#46;4</p></th><th><p class="p1">130</p></th><th><p class="p1">180</p></th><th><p class="p1">240</p></th><th><p class="p1">300</p></th></tr><tr><th><p class="p1">T94</p></th><th><p class="p1">23&#46;9×14&#46;2×7&#46;92</p></th><th><p class="p1">0&#46;362</p></th><th><p class="p1">5&#46;97</p></th><th><p class="p1">2&#46;16</p></th><th><p class="p1">60</p></th><th><p class="p1">0&#46;2105</p></th><th><p class="p1">1&#46;584</p></th><th><p class="p1">3&#46;44</p></th><th><p class="p1">22&#46;0</p></th><th><p class="p1">130</p></th><th><p class="p1">190</p></th><th><p class="p1">250</p></th><th><p class="p1">310</p></th></tr><tr><th><p class="p1">T106</p></th><th><p class="p1">26&#46;9×14&#46;5×11&#46;1</p></th><th><p class="p1">0&#46;659</p></th><th><p class="p1">6&#46;49</p></th><th><p class="p1">4&#46;28</p></th><th><p class="p1">93</p></th><th><p class="p1">0&#46;1936</p></th><th><p class="p1">1&#46;651</p></th><th><p class="p1">4&#46;49</p></th><th><p class="p1">31&#46;0</p></th><th><p class="p1">150</p></th><th><p class="p1">190</p></th><th><p class="p1">250</p></th><th><p class="p1">310</p></th></tr><tr><th><p class="p1">T106A</p></th><th><p class="p1">26&#46;9×14&#46;5×7&#46;92</p></th><th><p class="p1">0&#46;461</p></th><th><p class="p1">6&#46;49</p></th><th><p class="p1">3&#46;00</p></th><th><p class="p1">67</p></th><th><p class="p1">0&#46;1936</p></th><th><p class="p1">1&#46;651</p></th><th><p class="p1">3&#46;86</p></th><th><p class="p1">26&#46;8</p></th><th><p class="p1">150</p></th><th><p class="p1">190</p></th><th><p class="p1">250</p></th><th><p class="p1">310</p></th></tr><tr><th><p class="p1">T130</p></th><th><p class="p1">33×19&#46;8×11&#46;1</p></th><th><p class="p1">0&#46;698</p></th><th><p class="p1">8&#46;28</p></th><th><p class="p1">5&#46;78</p></th><th><p class="p1">81</p></th><th><p class="p1">0&#46;1518</p></th><th><p class="p1">3&#46;079</p></th><th><p class="p1">4&#46;75</p></th><th><p class="p1">42&#46;2</p></th><th><p class="p1">190</p></th><th><p class="p1">370</p></th><th><p class="p1">490</p></th><th><p class="p1">610</p></th></tr><tr><th><p class="p1">T131</p></th><th><p class="p1">33×16&#46;3×11&#46;1</p></th><th><p class="p1">0&#46;885</p></th><th><p class="p1">7&#46;72</p></th><th><p class="p1">6&#46;84</p></th><th><p class="p1">116</p></th><th><p class="p1">0&#46;1628</p></th><th><p class="p1">2&#46;087</p></th><th><p class="p1">5&#46;11</p></th><th><p class="p1">42&#46;1</p></th><th><p class="p1">170</p></th><th><p class="p1">250</p></th><th><p class="p1">330</p></th><th><p class="p1">410</p></th></tr><tr><th><p class="p1">T150</p></th><th><p class="p1">38&#46;4×21&#46;5×11&#46;1</p></th><th><p class="p1">0&#46;887</p></th><th><p class="p1">9&#46;38</p></th><th><p class="p1">8&#46;31</p></th><th><p class="p1">96</p></th><th><p class="p1">0&#46;134</p></th><th><p class="p1">3&#46;631</p></th><th><p class="p1">5&#46;28</p></th><th><p class="p1">53&#46;2</p></th><th><p class="p1">210</p></th><th><p class="p1">430</p></th><th><p class="p1">580</p></th><th><p class="p1">720</p></th></tr><tr><th><p class="p1">T157</p></th><th><p class="p1">39&#46;9×24&#46;1×14&#46;5</p></th><th><p class="p1">1&#46;06</p></th><th><p class="p1">10&#46;1</p></th><th><p class="p1">10&#46;7</p></th><th><p class="p1">100</p></th><th><p class="p1">0&#46;1174</p></th><th><p class="p1">4&#46;562</p></th><th><p class="p1">5&#46;89</p></th><th><p class="p1">63&#46;2</p></th><th><p class="p1">240</p></th><th><p class="p1">540</p></th><th><p class="p1">720</p></th><th><p class="p1">900</p></th></tr><tr><th><p class="p1">T184</p></th><th><p class="p1">46&#46;7×24&#46;1×18</p></th><th><p class="p1">1&#46;88</p></th><th><p class="p1">11&#46;2</p></th><th><p class="p1">21&#46;0</p></th><th><p class="p1">169</p></th><th><p class="p1">0&#46;1122</p></th><th><p class="p1">4&#46;562</p></th><th><p class="p1">7&#46;54</p></th><th><p class="p1">89&#46;2</p></th><th><p class="p1">250</p></th><th><p class="p1">540</p></th><th><p class="p1">720</p></th><th><p class="p1">900</p></th></tr><tr><th><p class="p1">T200</p></th><th><p class="p1">50&#46;8×31&#46;8×14</p></th><th><p class="p1">1&#46;27</p></th><th><p class="p1">13&#46;0</p></th><th><p class="p1">16&#46;4</p></th><th><p class="p1">92</p></th><th><p class="p1">0&#46;0967</p></th><th><p class="p1">7&#46;942</p></th><th><p class="p1">6&#46;50</p></th><th><p class="p1">90&#46;9</p></th><th><p class="p1">290</p></th><th><p class="p1">950</p></th><th><p class="p1">1270</p></th><th><p class="p1">1590</p></th></tr><tr><th><p class="p1">T200B</p></th><th><p class="p1">50&#46;8×31&#46;8×25&#46;4</p></th><th><p class="p1">2&#46;32</p></th><th><p class="p1">13&#46;0</p></th><th><p class="p1">30&#46;0</p></th><th><p class="p1">160</p></th><th><p class="p1">0&#46;0967</p></th><th><p class="p1">7&#46;942</p></th><th><p class="p1">8&#46;78</p></th><th><p class="p1">120</p></th><th><p class="p1">290</p></th><th><p class="p1">950</p></th><th><p class="p1">1270</p></th><th><p class="p1">1590</p></th></tr></tbody></table><p class="p1"> </p><p class="p1">&nbsp;&nbsp; 1)查图1或表2,可知75%μo时,H为25Oe。</p><p class="p1">&nbsp;&nbsp; 2)由表3中磁心的H/NI值,计算出安匝数,即:</p><p class="p1">  H=(H/NI)NI变换为NI=H/(H/NI)</p><p class="p1">试选T9026,该磁心的H/NI值为0&#46;2168。</p><p class="p1">NI=25/0&#46;2168=115&#46;3,取115</p><p class="p1">再由安匝数,求匝数</p><p class="p1">N=NI/I=115/3=38&#46;3,取38</p><p class="p1">计算电感量,该磁心的AL值为70nH/N2</p><p class="p1">L=N2AL=382×0&#46;07=101&#46;1μH</p><p class="p1">由于,此电感量接近所需值,故即可以38为所需匝数。如果,相差较多,则按公式(3)计算实际匝数。</p><p class="p1">3)由公式(3)计算匝数。</p><p class="p1">4)计算直流磁化力。</p><p class="p1">  NI=N×I=38×3=114</p><p class="p1">H=(H/NI)×NI=0&#46;2168×114=24&#46;7Oe</p><p class="p1">5)核对%μo,由图1或表2可知24&#46;7Oe,%μo&gt;75%,符合要求。</p><p class="p1">(2)方法二:由储能系数推算。</p><p class="p1">1)计算储能系数,按公式(6):</p><p class="p1">W=LI2/2=100×32/2=450μJ</p><p class="p1">2)由W推算出安匝数。变换公式(6′)可得:</p><p class="p1">NI=[2000W/AL]1/2</p><p class="p1">试选T9026,该磁心的AL值为70。</p><p class="p1">NI=[2000×450/70]1/2=113&#46;4,取113。</p><p class="p1">由安匝数计算N。</p><p class="p1">N=NI/I=113/3=37&#46;7,取38</p><p class="p1">计算电感量,</p><p class="p1">L=N2AL=382×0&#46;07=101&#46;1μH</p><p class="p1">以下步骤同方法一,不再列出。</p><p class="p1">上述两种方法,都要进行试选。如果试选不行,视情况找大或小一种的规格试选,直到满足要求为止。</p><p class="p1">(3)方法三:利用生产单位提供的两种曲线,(见图2,图3),查出所需磁心。</p><p class="p1">设计依据:电感量为100μH,额定电流为4A,在额定电流时,电感量不低于75μH。</p><p class="p1">1)计算储能系数。这里计算时,要求电感量为额定电流时的值,即75μH。</p><p class="p1" align="center">图2 材料--26μ<sub>0</sub>%与W关系曲线 </p><p class="p1" align="center">图3&nbsp; NI与W关系曲线</p><p class="p1">W=75×42/2=600μJ</p><p class="p1">2)查图2,600μJ与75%相交处为T106。</p><p class="p1">  再查图3,600μJ与T106相交之点安匝数约为130。</p><p class="p1">计算安匝数及电感量。</p><p class="p1">N=NI/I=130/4=32&#46;5,取33</p><p class="p1">L=332×0&#46;093=101&#46;3μH</p><p class="p1">此电感量为非额定电流时的值。</p><p class="p1">以后步骤同前。表4列出四种常用规格的铁粉心在几种μo条件下,不同电流时最大电感量。在设计时,通过查对表格,即可确定选用何种磁心(铁粉心的规格)。</p><p class="p1">表5列出不同额定电流,不同%μo时,不大于某个电感量时,可以选用的磁心规格。</p><p class="p1">表4四种常用规格的铁粉心不同电流时电感量</p><table border="1"><tbody><tr><th><p class="p1">%μo</p></th><th><p class="p1">50%</p></th><th><p class="p1">60%</p></th><th><p class="p1">70%</p></th><th><p class="p1">75%</p></th><th><p class="p1">80%</p></th><th><p class="p1">90%</p></th></tr><tr><th colspan="2"><p class="p1">T13026</p></th><th colspan="2"><p class="p1">33&#46;0×19&#46;8×11&#46;1</p></th><th colspan="3"><p class="p1">AL812A/mm2时NI240</p></th></tr><tr><th><p class="p1">NI</p></th><th><p class="p1">350</p></th><th><p class="p1">257</p></th><th><p class="p1">191</p></th><th><p class="p1">165</p></th><th><p class="p1">138</p></th><th><p class="p1">86</p></th></tr><tr><th><p class="p1">1A</p></th><th><p class="p1">9&#46;9mH</p></th><th><p class="p1">5&#46;3mH</p></th><th><p class="p1">2&#46;95mH</p></th><th><p class="p1">2&#46;2mH</p></th><th><p class="p1">1&#46;5mH</p></th><th><p class="p1">600μH</p></th></tr><tr><th><p class="p1">3A</p></th><th><p class="p1">1&#46;1mH</p></th><th><p class="p1">590μH</p></th><th><p class="p1">330μH</p></th><th><p class="p1">245μH</p></th><th><p class="p1">170μH</p></th><th><p class="p1">66&#46;6μH</p></th></tr><tr><th><p class="p1">5A</p></th><th><p class="p1">400μH</p></th><th><p class="p1">215μH</p></th><th><p class="p1">120μH</p></th><th><p class="p1">88μH</p></th><th><p class="p1">61&#46;7μH</p></th><th><p class="p1">24&#46;0μH</p></th></tr><tr><th><p class="p1">10A</p></th><th><p class="p1">100μH</p></th><th><p class="p1">53&#46;5μH</p></th><th><p class="p1">29&#46;5μH</p></th><th><p class="p1">22μH</p></th><th><p class="p1">15&#46;4μH</p></th><th><p class="p1">6&#46;0μH</p></th></tr><tr><th colspan="2"><p class="p1">T10626</p></th><th colspan="2"><p class="p1">26&#46;9×14&#46;5×11&#46;1</p></th><th colspan="3"><p class="p1">AL932A/mm2时NI130</p></th></tr><tr><th><p class="p1">NI</p></th><th><p class="p1">274</p></th><th><p class="p1">202</p></th><th><p class="p1">150</p></th><th><p class="p1">130</p></th><th><p class="p1">108</p></th><th><p class="p1">67</p></th></tr><tr><th><p class="p1">1A</p></th><th><p class="p1">7&#46;0mH</p></th><th><p class="p1">3&#46;8mH</p></th><th><p class="p1">2&#46;1mH</p></th><th><p class="p1">1&#46;6mH</p></th><th><p class="p1">1&#46;1mH</p></th><th><p class="p1">410μH</p></th></tr><tr><th><p class="p1">3A</p></th><th><p class="p1">775μH</p></th><th><p class="p1">420μH</p></th><th><p class="p1">230μH</p></th><th><p class="p1">175μH</p></th><th><p class="p1">120μH</p></th><th><p class="p1">46μH</p></th></tr><tr><th><p class="p1">5A</p></th><th><p class="p1">280μH</p></th><th><p class="p1">150μH</p></th><th><p class="p1">85μH</p></th><th><p class="p1">60μH</p></th><th><p class="p1">43μH</p></th><th><p class="p1">16&#46;7μH</p></th></tr><tr><th><p class="p1">10A</p></th><th><p class="p1">70μH</p></th><th><p class="p1">37&#46;9μH</p></th><th><p class="p1">20&#46;9μH</p></th><th><p class="p1">15&#46;7μH</p></th><th><p class="p1">10&#46;8μH</p></th><th><p class="p1">4&#46;2μH</p></th></tr><tr><th colspan="2"><p class="p1">T9026</p></th><th colspan="2"><p class="p1">22&#46;9×14&#46;0×9&#46;53</p></th><th colspan="3"><p class="p1">AL702A/mm2时NI120</p></th></tr><tr><th><p class="p1">NI</p></th><th><p class="p1">244</p></th><th><p class="p1">180</p></th><th><p class="p1">133</p></th><th><p class="p1">115</p></th><th><p class="p1">97</p></th><th><p class="p1">60</p></th></tr><tr><th><p class="p1">1A</p></th><th><p class="p1">4&#46;2mH</p></th><th><p class="p1">2&#46;3mH</p></th><th><p class="p1">1&#46;2mH</p></th><th><p class="p1">925μH</p></th><th><p class="p1">660μH</p></th><th><p class="p1">250μH</p></th></tr><tr><th><p class="p1">2A</p></th><th><p class="p1">1&#46;0mH</p></th><th><p class="p1">560μH</p></th><th><p class="p1">310μH</p></th><th><p class="p1">230μH</p></th><th><p class="p1">165μH</p></th><th><p class="p1">63μH</p></th></tr><tr><th><p class="p1">3A</p></th><th><p class="p1">460μH</p></th><th><p class="p1">250μH</p></th><th><p class="p1">137μH</p></th><th><p class="p1">102μH</p></th><th><p class="p1">73μH</p></th><th><p class="p1">28μH</p></th></tr><tr><th><p class="p1">5A</p></th><th><p class="p1">165μH</p></th><th><p class="p1">90μH</p></th><th><p class="p1">50μH</p></th><th><p class="p1">37μH</p></th><th><p class="p1">26μH</p></th><th><p class="p1">10μH</p></th></tr><tr><th colspan="2"><p class="p1">T8026</p></th><th colspan="2"><p class="p1">20&#46;2×12&#46;6×6&#46;35</p></th><th colspan="3"><p class="p1">AL462A/mm2时NI100</p></th></tr><tr><th><p class="p1">NI</p></th><th><p class="p1">217</p></th><th><p class="p1">160</p></th><th><p class="p1">120</p></th><th><p class="p1">102</p></th><th><p class="p1">86</p></th><th><p class="p1">53</p></th></tr><tr><th><p class="p1">1A</p></th><th><p class="p1">2&#46;2mH</p></th><th><p class="p1">1&#46;2mH</p></th><th><p class="p1">660μH</p></th><th><p class="p1">480μH</p></th><th><p class="p1">340μH</p></th><th><p class="p1">130μH</p></th></tr><tr><th><p class="p1">2A</p></th><th><p class="p1">540μH</p></th><th><p class="p1">290μH</p></th><th><p class="p1">165μH</p></th><th><p class="p1">120μH</p></th><th><p class="p1">85μH</p></th><th><p class="p1">32μH</p></th></tr><tr><th><p class="p1">3A</p></th><th><p class="p1">240μH</p></th><th><p class="p1">130μH</p></th><th><p class="p1">75μH</p></th><th><p class="p1">50μH</p></th><th><p class="p1">40μH</p></th><th><p class="p1">15μH</p></th></tr><tr><th><p class="p1">4A</p></th><th><p class="p1">135μH</p></th><th><p class="p1">75μH</p></th><th><p class="p1">40μH</p></th><th><p class="p1">30μH</p></th><th><p class="p1">20μH</p></th><th><p class="p1">8μH</p></th></tr></tbody></table><p class="p1">表5不同额定电流所需电感量选用何种磁心</p><table border="1"><tbody><tr><th><p class="p1">A</p></th><th><p class="p1">μH</p></th><th><p class="p1">μo50%</p></th><th><p class="p1">μo60%</p></th><th><p class="p1">μo70%</p></th><th><p class="p1">μo75%</p></th><th><p class="p1">μo80%</p></th><th><p class="p1">μo90%</p></th></tr><tr><th><p class="p1">1</p></th><th><p class="p1">100</p></th><th><p class="p1">T2626</p></th><th><p class="p1">T3726</p></th><th><p class="p1">T4426</p></th><th><p class="p1">T5026</p></th><th><p class="p1">T5026B</p></th><th><p class="p1">T8026</p></th></tr><tr><th><p class="p1"> </p></th><th><p class="p1">200</p></th><th><p class="p1">T3826</p></th><th><p class="p1">T5026</p></th><th><p class="p1">T5026B</p></th><th><p class="p1">T6026</p></th><th><p class="p1">T6826</p></th><th><p class="p1">T9026</p></th></tr><tr><th><p class="p1"> </p></th><th><p class="p1">300</p></th><th><p class="p1">T5026</p></th><th><p class="p1">T5026B</p></th><th><p class="p1">T6826</p></th><th><p class="p1">——</p></th><th><p class="p1">T7226</p></th><th><p class="p1">T10626</p></th></tr><tr><th><p class="p1"> </p></th><th><p class="p1">500</p></th><th><p class="p1">——</p></th><th><p class="p1">T6826</p></th><th><p class="p1">T8026</p></th><th><p class="p1">T7226</p></th><th><p class="p1">T9826</p></th><th><p class="p1">T13026</p></th></tr><tr><th><p class="p1">2</p></th><th><p class="p1">30</p></th><th><p class="p1">T3726</p></th><th><p class="p1">T3826</p></th><th><p class="p1">T5026</p></th><th><p class="p1">T5026B</p></th><th><p class="p1">——</p></th><th><p class="p1">T8026</p></th></tr><tr><th><p class="p1"> </p></th><th><p class="p1">50</p></th><th><p class="p1">T3826</p></th><th><p class="p1">T5026</p></th><th><p class="p1">T5026B</p></th><th><p class="p1">T6026</p></th><th><p class="p1">T8026</p></th><th><p class="p1">T9026</p></th></tr><tr><th><p class="p1"> </p></th><th><p class="p1">100</p></th><th><p class="p1">T5026</p></th><th><p class="p1">T6026</p></th><th><p class="p1">——</p></th><th><p class="p1">T7226</p></th><th><p class="p1">T8026B</p></th><th><p class="p1">T10626</p></th></tr><tr><th><p class="p1"> </p></th><th><p class="p1">200</p></th><th><p class="p1">——</p></th><th><p class="p1">T7226</p></th><th><p class="p1">T9426</p></th><th><p class="p1">T10626A</p></th><th><p class="p1">T10626</p></th><th><p class="p1">T15026</p></th></tr><tr><th><p class="p1">3</p></th><th><p class="p1">40</p></th><th><p class="p1">T5026B</p></th><th><p class="p1">T6026</p></th><th><p class="p1">——</p></th><th><p class="p1">T7226</p></th><th><p class="p1">T8026B</p></th><th><p class="p1">T10626</p></th></tr><tr><th><p class="p1"> </p></th><th><p class="p1">60</p></th><th><p class="p1">T6026</p></th><th><p class="p1">——</p></th><th><p class="p1">T7226</p></th><th><p class="p1">T8026B</p></th><th><p class="p1">T9026</p></th><th><p class="p1">T13026</p></th></tr><tr><th><p class="p1"> </p></th><th><p class="p1">100</p></th><th><p class="p1">——</p></th><th><p class="p1">T7226</p></th><th><p class="p1">T9026</p></th><th><p class="p1">T10626A</p></th><th><p class="p1">T10626</p></th><th><p class="p1">T15726</p></th></tr><tr><th><p class="p1"> </p></th><th><p class="p1">200</p></th><th><p class="p1">T9426</p></th><th><p class="p1">T10626A</p></th><th><p class="p1">——</p></th><th><p class="p1">T13026</p></th><th><p class="p1">T15026</p></th><th><p class="p1">T18426</p></th></tr><tr><th><p class="p1">4</p></th><th><p class="p1">20</p></th><th><p class="p1">T5026</p></th><th><p class="p1">——</p></th><th><p class="p1">T6826</p></th><th><p class="p1">——</p></th><th><p class="p1">T7226</p></th><th><p class="p1">T10626A</p></th></tr><tr><th><p class="p1"> </p></th><th><p class="p1">40</p></th><th><p class="p1">T6826</p></th><th><p class="p1">——</p></th><th><p class="p1">T7226</p></th><th><p class="p1">T9426</p></th><th><p class="p1">T10626A</p></th><th><p class="p1">T13126</p></th></tr><tr><th><p class="p1">5</p></th><th><p class="p1">20</p></th><th><p class="p1">——</p></th><th><p class="p1">T6826</p></th><th><p class="p1">T8026</p></th><th><p class="p1">T7226</p></th><th><p class="p1">T9026</p></th><th><p class="p1">T13026</p></th></tr><tr><th><p class="p1"> </p></th><th><p class="p1">40</p></th><th><p class="p1">T8026</p></th><th><p class="p1">T8026B</p></th><th><p class="p1">——</p></th><th><p class="p1">T10626A</p></th><th><p class="p1">T10626</p></th><th><p class="p1">T15726</p></th></tr><tr><th><p class="p1"> </p></th><th><p class="p1">60</p></th><th><p class="p1">T8026B</p></th><th><p class="p1">T10626A</p></th><th><p class="p1">T10626</p></th><th><p class="p1">T13026</p></th><th><p class="p1">T13126</p></th><th><p class="p1">T17526</p></th></tr><tr><th><p class="p1"> </p></th><th><p class="p1">80</p></th><th><p class="p1">T9026</p></th><th><p class="p1">T10626</p></th><th><p class="p1">T13026</p></th><th><p class="p1">T13126</p></th><th><p class="p1">T15726</p></th><th><p class="p1">T18426</p></th></tr><tr><th><p class="p1"> </p></th><th><p class="p1">100</p></th><th><p class="p1">T10626A</p></th><th><p class="p1">T10626</p></th><th><p class="p1">T13126</p></th><th><p class="p1">T15026</p></th><th><p class="p1">T15726</p></th><th><p class="p1">T20026B</p></th></tr><tr><th><p class="p1">10</p></th><th><p class="p1">4</p></th><th><p class="p1">T5026B</p></th><th><p class="p1">T6026</p></th><th><p class="p1">——</p></th><th><p class="p1">T7226</p></th><th><p class="p1">T8026B</p></th><th><p class="p1">T10626</p></th></tr><tr><th><p class="p1"> </p></th><th><p class="p1">6</p></th><th><p class="p1">T6026</p></th><th><p class="p1">——</p></th><th><p class="p1">T7226</p></th><th><p class="p1">T9426</p></th><th><p class="p1">T10626A</p></th><th><p class="p1">T13126</p></th></tr><tr><th><p class="p1"> </p></th><th><p class="p1">10</p></th><th><p class="p1">T8026</p></th><th><p class="p1">T8026B</p></th><th><p class="p1">——</p></th><th><p class="p1">T10626A</p></th><th><p class="p1">T10626</p></th><th><p class="p1">T15726</p></th></tr><tr><th><p class="p1"> </p></th><th><p class="p1">15</p></th><th><p class="p1">T8026B</p></th><th><p class="p1">T10626A</p></th><th><p class="p1">T10626</p></th><th><p class="p1">T13026</p></th><th><p class="p1">T13126</p></th><th><p class="p1">T17526</p></th></tr><tr><th><p class="p1"> </p></th><th><p class="p1">20</p></th><th><p class="p1">T9026</p></th><th><p class="p1">T10626</p></th><th><p class="p1">T13026</p></th><th><p class="p1">T13126</p></th><th><p class="p1">T15726</p></th><th><p class="p1">T18426</p></th></tr></tbody></table><p class="p1">最后,需要指出的是,方法一、二计算出来的安匝数,有时会很大,实际上可能绕不下。因此,还要根据下列公式验算一下。</p><p class="p1">NI=KSoJ(7)</p><p class="p1">式中K为窗口利用系数,取0&#46;4。</p><p class="p1">So为磁心窗口面积,单位为mm2。</p><p class="p1">J为电流密度,单位为A/mm2。一般可取2~4A/mm2。电流密度大了,可绕较多匝数,但铜耗增大,线圈温升高。</p><p class="p1">表3右部列有不同电流密度时磁心可绕安匝数作为参考。</p><p class="p1">6温升核算</p><p class="p1">(1)计算Bac</p><p class="p1">Bac=L△I×102/2AeN=</p><p class="p1">(75×0&#46;75×100)/2×0&#46;395×38=187&#46;4(GS)</p><p class="p1">(2)计算单位体积功耗和铁损</p><p class="p1">core=6&#46;94×10-10f1&#46;36B2&#46;03(f:Hz,B:GS)</p><p class="p1">=6&#46;94×10-10×(100×103)1&#46;36×(187&#46;4)2&#46;03</p><p class="p1">=179&#46;9mW/cm3</p><p class="p1">Fe=Pcore×Ve=179&#46;9×2&#46;28=410&#46;2mw</p><p class="p1">(3)计算铜损</p><p class="p1">cu=(N×l/N)×ρ×I2</p><p class="p1">I0=3A,使用#19,每cm长0&#46;264mΩ</p><p class="p1">Pcu=38×3&#46;64×0&#46;264×32=328&#46;6mW</p><p class="p1">(4)计算温升</p><p class="p1">△T=|(PFe+Pcu)/SA|0&#46;833=|(410&#46;2+328&#46;6)/</p><p class="p1">22&#46;4|0&#46;833=18&#46;4℃</p><p class="p1">此温升不算高,完全可以使用。</p><p class="p1">参考文献</p><p class="p1">1美国微金属公司产品目录。</p>
发表于 2010-11-16 16:52:27 | 显示全部楼层
太棒了,找了很久這個最詳細.謝謝

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