EMC optimized tsim qauv rau kev hloov fais fab mov PCB
Txoj kev cuam tshuam ntawm kev hloov hom hloov suab nrov muab cov kev sib txuas rau qhov cuam tshuam thiab cov khoom siv cuam tshuam, thiab kev tshawb fawb ntawm nws cov hom kev cuam tshuam thiab qhov sib txawv hom cuam tshuam yog qhov tseem ceeb tshwj xeeb. Feem ntau txheeb xyuas cov qauv siv hluav taws xob ntau ntawm cov khoom tseem ceeb ntawm Circuit Court, nrog rau cov qauv hauv Circuit Court ntawm hom sib txawv thiab txawv hom suab nrov, muab kev pab cuam zoo rau EMC optimization tsim ntawm hloov hluav taws xob PCBs.
Hom kev cuam tshuam thiab kev sib txawv ntawm hom kev cuam tshuam ntawm kev hloov cov khoom siv hluav taws xob muaj qhov sib txawv ntawm lub voj voog. Feem ntau, qhov sib txawv hom suab nrov dominates ntawm tsawg frequencies thiab hom hom suab nrov dominates ntawm high frequencies. Tsis tas li ntawd, cov hluav taws xob hluav taws xob ntawm hom hom tam sim no feem ntau yog ntau dua li qhov sib txawv ntawm hom tam sim no. Yog li ntawd, nws yog ib qho tsim nyog yuav tsum paub qhov txawv ntawm qhov sib txawv hom cuam tshuam thiab hom kev cuam tshuam hauv cov khoom siv hluav taws xob.
Txhawm rau kom paub qhov txawv ntawm qhov sib txawv ntawm qhov cuam tshuam thiab hom kev cuam tshuam, peb thawj zaug yuav tsum tau kawm txog hom kev sib txuas ntawm cov khoom siv hluav taws xob hloov pauv. Raws li qhov no, peb tuaj yeem tsim txoj hauv kev rau kev sib txawv hom suab nrov tam sim no thiab hom suab nrov tam sim no. Lub conduction coupling ntawm switching fais fab mov feem ntau muaj xws li:
Circuit Court raws li conductive coupling, capacitive coupling, inductive coupling, thiab ib tug ua ke ntawm cov coupling txoj kev.
1 Hom hom thiab txawv hom suab nrov txoj kev qauv
Hauv kev hloov cov khoom siv hluav taws xob, hom suab nrov nrov thiab qhov sib txawv hom suab nrov txoj hauv kev yog tsim los ntawm kev sib txuas capacitance CW ntawm lub hauv paus thiab theem nrab windings ntawm high-frequency transformers, stray capacitance CK ntawm lub hwj chim raj thiab cov dab dej kub, cov kab mob parasitic ntawm lub hwj chim raj. lawv tus kheej, thiab kev sib nrig sib inductance, tus kheej inductance, kev sib nrig sib capacitance, tus kheej capacitance, impedance thiab lwm yam parasitic tsis tsim los ntawm kev sib nrig sib coupling ntawm cov xov hlau luam tawm, uas ua rau cov hom sib txawv thiab txawv hom kev cuam tshuam. Raws li kev txheeb xyuas cov kab mob parasitic cov qauv ntawm kev tiv thaiv, inductance, thiab capacitance ntawm lub zog hloov khoom siv, transformers, thiab cov xov hlau luam tawm, lub suab nrov tam sim no tus qauv ntawm lub converter tuaj yeem tau txais.
High zaus qauv ntawm lub ntsiab Cheebtsam ntawm 2 Circuit Court
Internal parasitic inductance thiab capacitance ntawm lub hwj chim hloov cuam tshuam rau kev ua haujlwm siab ntawm Circuit Court. Cov capacitors no ua rau muaj kev cuam tshuam ntau zaus ntws mus rau cov hlau substrate, thiab muaj ib qho CK capacitor ntawm lub hwj chim hloov thiab lub dab dej kub. Rau kev nyab xeeb vim li cas, lub dab dej kub feem ntau yog hauv av, muab txoj hauv kev nrov nrov.
Thaum lub sijhawm ua haujlwm ntawm PWM converters, hom suab nrov kuj raug tsim nrog rau kev ua haujlwm ntawm kev hloov khoom siv. Raws li pom nyob rau hauv daim duab 1, rau ib nrab choj converter, qhov hluav taws xob xau ntawm hloov Q1 yog ib txwm U1, thiab cov peev txheej muaj peev xwm sib txawv ntawm 0 thiab U1/2 nrog kev hloov pauv ntawm lub xeev; Qhov peev xwm ntawm Q2 ib txwm yog 0, thiab qhov dej ntws tau txawv ntawm 0 thiab U1/2. Txhawm rau kom muaj kev sib cuag zoo ntawm lub raj hloov pauv thiab lub tshuab hluav taws xob, cov khoom siv hluav taws xob los yog cov khoom siv silicone nrog cov thermal conductivity zoo feem ntau ntxiv rau hauv qab ntawm lub raj hloov thiab lub radiator. Qhov no tshwm sim nyob rau hauv lub xub ntiag ntawm ib tug parallel coupling capacitor CK ntawm point A thiab hauv av. Thaum lub xeev hloov cov raj Q1 thiab Q2 hloov pauv, ua rau muaj kev hloov pauv ntawm qhov muaj peev xwm ntawm point A, lub suab nrov tam sim no Ik yuav raug tsim tawm ntawm CK, raws li qhia hauv daim duab 2. Cov tam sim no ntws los ntawm lub dab dej kub mus rau hauv lub casing, uas muaj ib tug coupling impedance nrog rau lub ntsiab fais fab kab, tsim ib hom suab nrov txoj kev raws li qhia los ntawm cov dashed kab nyob rau hauv daim duab 2. Yog li ntawd, hom hom suab nrov tam sim no generates ib tug voltage poob ntawm lub coupling impedance Z ntawm hauv av thiab lub ntsiab fais fab kab, sib sau hom suab nrov.
