Kev sib txuas lus Switching Power Supply Yam ntxwv thiab Electromagnetic Interference Mechanism
Cov yam ntxwv tseem ceeb ntawm kev hloov fais fab mov
Muaj plaub yam tseem ceeb ntawm kev hloov fais fab mov:
①Qhov chaw yog qhov tseeb. Feem ntau tsom rau lub zog hloov khoom siv, diodes, radiators thiab high-frequency transformers txuas nrog lawv;
② Lub zog hloov khoom siv ua haujlwm hauv lub xeev hloov pauv. Vim tias qhov hloov hluav taws xob hloov hluav taws xob yog lub zog hloov hluav taws xob uas ua haujlwm hauv lub xeev hloov pauv, nws qhov hluav taws xob thiab qhov hloov pauv tam sim no siab heev, thiab qhov cuam tshuam kev siv hluav taws xob yog qhov loj;
③ Fais fab luam ntawv Circuit Court board (PCB) thaiv feem ntau yog teem manually. Qhov kev npaj no ua rau nws tsis tshua muaj, uas ua rau muaj qhov 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 qhov loj, txij li kaum tawm txhiab Hz mus rau ob peb megahertz. Cov ntaub ntawv tseem ceeb ntawm kev cuam tshuam yog kev cuam tshuam kev cuam tshuam thiab kev cuam tshuam ze ntawm thaj chaw.
Lub mechanism ntawm electromagnetic cuam tshuam
1.2.1 Electromagnetic cuam tshuam los ntawm kev hloov circuits
Lub tshuab hluav taws xob hloov hluav taws xob yog lub hauv paus ntawm lub zog hloov hluav taws xob. Nws yog tsuas yog tsim los ntawm lub raj hloov pauv thiab lub tshuab hluav taws xob ntau zaus. Lub dv/dt generated los ntawm nws yog ib tug mem tes nrog ib tug kuj loj amplitude, ib tug dav zaus band thiab nplua nuj harmonics. Muaj ob lub laj thawj tseem ceeb rau qhov kev cuam tshuam ntawm cov mem tes: ntawm ib sab, qhov hloov lub raj thauj khoom yog thawj kauj ntawm lub tshuab hluav taws xob ntau zaus, uas yog qhov inductive load. Thaum lub sij hawm thaum lub hloov lub raj yog qhib, lub hauv paus kauj tsim ib tug loj inrush tam sim no, thiab ib tug high surge ncov voltage tshwm nyob rau hauv ob qho tib si kawg ntawm thawj kauj; Thaum lub qhov hluav taws xob hloov hluav taws xob raug muab tua, vim yog cov dej ntws tawm ntawm lub hauv paus kauj, ib feem ntawm lub zog Yog tias tsis muaj kev sib kis ntawm thawj kauj mus rau theem nrab kauj, qhov no ntawm lub zog khaws cia hauv inductor yuav tsim ib qho attenuating. oscillation nrog ib tug spike nrog lub capacitance thiab kuj nyob rau hauv lub collector Circuit Court, uas yog superimposed nyob rau hauv lub turn-off voltage los tsim ib tug tig-off voltage spike. Qhov kev cuam tshuam ntawm lub zog hluav taws xob no yuav ua rau tib lub magnetizing inrush tam sim no ib ntus raws li thaum lub hauv paus kauj yog qhib, thiab lub suab nrov no yuav raug coj mus rau cov tswv yim thiab cov zis tawm los tsim kev cuam tshuam. Ntawm qhov tod tes, lub siab hloov pauv tam sim no lub voj voog tsim los ntawm thawj kauj ntawm lub mem tes transformer, lub raj hloov thiab lub lim capacitor tuaj yeem tsim hluav taws xob ntau qhov chaw thiab tsim hluav taws xob cuam tshuam.
1.2.2 Kev cuam tshuam los ntawm lub sijhawm rov qab los ntawm lub diode Thaum lub diode rectifier nyob rau hauv lub high-frequency rectification circuit yog forward-conducting, ib tug loj rau pem hauv ntej tam sim no ntws los ntawm nws. Thaum nws rov qab-biased thiab tig mus rau kev txiav tawm, vim muaj ntau cov cab kuj sib sau ua ke, yog li tam sim no yuav ntws mus rau qhov tsis sib xws rau ib lub sijhawm ua ntej cov nqa khoom ploj mus, ua rau muaj kev poob qis hauv kev rov qab los. tam sim no ntawm tus cab kuj ploj lawm thiab ib tug loj tam sim no hloov (di/dt).
2 Electromagnetic Interference Suppression Measures
Peb lub ntsiab lus uas tsim electromagnetic cuam tshuam yog qhov cuam tshuam, kev nthuav dav thiab cov khoom cuam tshuam. Yog li ntawd, kev cuam tshuam ntawm electromagnetic cuam tshuam yuav tsum tau ua los ntawm peb yam no.
Lub hom phiaj ntawm kev cuam tshuam qhov cuam tshuam, tshem tawm qhov sib txuas thiab hluav taws xob ntawm qhov cuam tshuam thiab cov khoom cuam tshuam, thiab txhim kho qhov muaj peev xwm tiv thaiv kev cuam tshuam ntawm cov cuab yeej cuam tshuam, yog li txhim kho cov khoom siv hluav taws xob sib raug zoo ntawm kev hloov hluav taws xob.
2.1 Siv lim los tiv thaiv electromagnetic cuam tshuam
Kev lim dej yog ib txoj hauv kev tseem ceeb los tiv thaiv kev cuam tshuam electromagnetic. Nws tuaj yeem cuam tshuam cov electromagnetic cuam tshuam hauv daim phiaj hluav taws xob los ntawm kev nkag mus rau hauv cov khoom siv, thiab tseem tuaj yeem tiv thaiv kev cuam tshuam ntawm electromagnetic hauv cov cuab yeej los ntawm kev nkag mus rau hauv daim phiaj hluav taws xob. Txhim kho cov hloov hluav taws xob hloov lim dej hauv cov khoom siv hluav taws xob thiab cov khoom siv hluav taws xob hloov hluav taws xob tuaj yeem tsis tsuas yog daws qhov teeb meem ntawm kev cuam tshuam kev cuam tshuam, tab sis kuj yog ib qho cuab yeej tseem ceeb los daws qhov cuam tshuam hluav taws xob. Filter suppression technology muab faib ua ob txoj hauv kev: passive filtering thiab active filtering.
2.1.1 Passive filtering technology
Lub passive lim Circuit Court yog yooj yim, tsis tshua muaj nqi, txhim khu kev qha hauv kev ua tau zoo, thiab yog ib txoj hauv kev zoo los cuam tshuam electromagnetic cuam tshuam. Passive lim yog tsim los ntawm inductors, capacitors, thiab resistors, thiab lawv lub luag haujlwm ncaj qha yog los daws cov emissions. hloov hluav taws xob
