Cov yam ntxwv ntawm Switching Power Supply thiab Mechanism of Electromagnetic Interference Generation
Muaj plaub yam tseem ceeb ntawm kev hloov cov khoom siv hluav taws xob:
① Qhov chaw yog qhov tseeb. Feem ntau yog tsom rau ntawm cov khoom siv hluav taws xob hloov hluav taws xob, diodes, thiab cov khoom siv hluav taws xob sib txuas thiab cov tshuab hluav taws xob ntau zaus;
② Lub zog hloov hluav taws xob ua haujlwm hauv lub xeev qhib / tawm. Vim qhov tseeb tias lub zog hloov hluav taws xob yog lub zog hloov hluav taws xob uas ua haujlwm hauv lub xeev hloov pauv, nws qhov voltage thiab tam sim no hloov pauv tau siab, ua rau muaj kev cuam tshuam loj heev;
③ Kev xaim hluav taws xob luam tawm Circuit Board (PCBs) feem ntau yog manually teem. Qhov kev npaj no ua rau nws tsis txaus ntseeg, ua rau muaj kev nyuaj ntawm kev rho tawm PCB faib tsis tau thiab kwv yees thiab ntsuas kev cuam tshuam ze ntawm thaj chaw;
④ Hloov zaus yog loj, xws li kaum tawm txhiab Hz mus rau ob peb megahertz. Cov ntaub ntawv tseem ceeb ntawm kev cuam tshuam yog kev cuam tshuam thiab kev cuam tshuam ze ntawm thaj chaw.
Mechanism ntawm electromagnetic cuam tshuam tiam
Electromagnetic cuam tshuam generated los ntawm switching circuits
Lub tshuab hluav taws xob hloov hluav taws xob yog qhov tseem ceeb ntawm cov khoom siv hluav taws xob hloov hluav taws xob, feem ntau yog tsim los ntawm kev hloov cov raj thiab cov tshuab hluav taws xob ntau zaus. Lub dv/dt generated los ntawm nws yog ib tug mem tes nrog ib tug loj amplitude, ib tug dav zaus band, thiab nplua nuj harmonics. Lub ntsiab yog vim li cas rau qhov no mem tes cuam tshuam yog ob npaug: ntawm ib sab, lub hloov raj load yog thawj kauj ntawm ib tug high-frequency transformer, uas yog ib tug inductive load. Thaum lub sij hawm thaum lub hloov lub raj yog qhib, lub hauv paus coil generates ib tug loj surge tam sim no thiab ib tug high surge ncov voltage tshwm nyob rau hauv ob qho tib si kawg ntawm thawj kauj; Thaum lub sij hawm hloov lub raj disconnection, vim yog cov xau flux ntawm thawj kauj, ib feem ntawm lub zog tsis xa los ntawm thawj kauj mus rau theem ob. Lub zog khaws cia nyob rau hauv inductor yuav tsim ib tug decaying oscillation nrog spikes nrog rau lub capacitance thiab kuj nyob rau hauv lub collector Circuit Court, uas yuav superimposed nyob rau hauv lub tig tawm voltage los tsim ib tug tig tawm voltage spike. Hom kev siv hluav taws xob tam sim no cuam tshuam yuav ua rau tib lub magnetization surge tam sim no ib ntus raws li thaum lub hauv paus kauj txuas nrog, thiab lub suab nrov no yuav raug xa mus rau cov khoom siv thiab cov khoom siv tawm, tsim kev cuam tshuam. Ntawm qhov tod tes, lub voj voog loj hloov tam sim no tsim los ntawm thawj kauj, hloov raj, thiab lim capacitor ntawm cov mem tes transformer tuaj yeem tsim hluav taws xob tseem ceeb, tsim hluav taws xob cuam tshuam.
Qhov cuam tshuam los ntawm lub sijhawm rov qab los ntawm diode nyob rau hauv high-frequency rectifier Circuit Court yog tshwm sim los ntawm ib tug loj rau pem hauv ntej tam sim no ntws los ntawm lub rectifier diode thaum lub sij hawm rau pem hauv ntej conduction. Thaum nws raug muab tua vim qhov rov qab tsis zoo voltage, vim muaj ntau cov cab kuj nyob rau hauv lub PN hlws ris, tam sim no yuav ntws nyob rau hauv lub opposite kev taw qhia thaum lub sij hawm ua ntej cov cab kuj ploj mus, ua rau ib tug ntse txo nyob rau hauv lub rov qab tam sim no. cov neeg nqa khoom ploj mus thiab ua rau muaj kev hloov pauv tseem ceeb tam sim no (di/dt).
Electromagnetic cuam tshuam kev tiv thaiv
Peb lub ntsiab lus uas tsim electromagnetic cuam tshuam yog qhov cuam tshuam, kev nthuav tawm, thiab cov cuab yeej cuam tshuam. Yog li ntawd, suppressing electromagnetic cuam tshuam yuav tsum tau ua los ntawm peb yam no.
Lub hom phiaj yog txhawm rau txhawm rau cuam tshuam cov peev txheej, tshem tawm kev sib txuas thiab hluav taws xob ntawm cov khoom cuam tshuam thiab cov cuab yeej cuam tshuam, txhim kho qhov muaj peev xwm tiv thaiv kev cuam tshuam ntawm cov khoom cuam tshuam, thiab yog li txhim kho cov khoom siv hluav taws xob sib xyaw ua ke ntawm kev hloov hluav taws xob.
Siv cov ntxaij lim dej los tiv thaiv kev cuam tshuam electromagnetic
Kev lim dej yog ib txoj hauv kev tseem ceeb rau kev tiv thaiv electromagnetic cuam tshuam, uas tuaj yeem cuam tshuam electromagnetic cuam tshuam nkag mus rau hauv cov khoom siv hauv daim phiaj hluav taws xob thiab tseem cuam tshuam electromagnetic cuam tshuam nkag mus rau hauv daim phiaj hluav taws xob hauv cov khoom siv. Txhim kho lub tshuab hluav taws xob hloov pauv hauv cov khoom siv hluav taws xob thiab cov khoom siv hluav taws xob hloov pauv tsis tuaj yeem daws qhov teeb meem ntawm kev cuam tshuam, tab sis kuj yog ib qho cuab yeej tseem ceeb rau kev daws teeb meem hluav taws xob cuam tshuam. Lub tshuab lim lim tau muab faib ua ob txoj hauv kev: passive filtering thiab nquag lim.
Passive filtering tshuab
Passive filtering circuits yog qhov yooj yim, siv tau zoo, thiab txhim khu kev qha, ua rau lawv txoj hauv kev zoo los cuam tshuam electromagnetic cuam tshuam. Passive lim yog tsim los ntawm inductance, capacitance, thiab cov khoom tiv thaiv, thiab lawv txoj haujlwm ncaj qha yog los daws cov emissions.
Vim lub peev xwm loj ntawm lub lim dej capacitor nyob rau hauv thawj lub hwj huam mov Circuit Court, mem tes ncov tam sim no yog tsim nyob rau hauv lub rectifier Circuit Court, uas yog tsim los ntawm ib tug loj tus naj npawb ntawm high-order harmonic tam sim no thiab ua rau muaj kev cuam tshuam rau lub hwj chim daim phiaj; Tsis tas li ntawd, qhov kev coj ua lossis kev txiav tawm ntawm lub raj hloov pauv hauv lub voj voog, nrog rau cov kauj ruam tseem ceeb ntawm lub transformer, yuav tsim cov pulsating tam sim no. Vim tias qhov kev hloov pauv tam sim no siab, induced tam sim no ntawm cov zaus sib txawv yog tsim nyob rau hauv ib puag ncig circuits, nrog rau kev sib txawv thiab hom kev cuam tshuam cov teeb liab. Cov teeb liab cuam tshuam no tuaj yeem xa mus rau lwm cov kab ntawm daim phiaj hluav taws xob thiab cuam tshuam nrog lwm cov khoom siv hluav taws xob los ntawm ob txoj kab hluav taws xob. Qhov sib txawv hom kev lim dej hauv daim duab tuaj yeem txo qhov sib txawv ntawm qhov cuam tshuam cov teeb liab hauv kev hloov hluav taws xob, thiab tuaj yeem ua rau cov teeb liab cuam tshuam electromagnetic cuam tshuam los ntawm cov cuab yeej nws tus kheej thaum ua haujlwm thiab xa mus rau hauv daim phiaj hluav taws xob. Raws li txoj cai ntawm electromagnetic induction, E-Ldi / dt yog tau, qhov twg E yog qhov voltage poob ntawm ob kawg ntawm L, L yog inductance, thiab di / dt yog tus nqi ntawm tam sim no hloov. Pom tseeb, qhov me me ntawm qhov hloov pauv tam sim no, ntau dua qhov xav tau inductance.
