Kev soj ntsuam ntawm Electromagnetic Disturbance Sources nyob rau hauv High Frequency Switching Power Supplies
Yog hais tias qhov teeb meem ntawm electromagnetic cuam tshuam (EMI) uas twb muaj lawm nyob rau hauv high-frequency switching fais fab mov nws tus kheej tsis tau ua kom zoo, nws tsis yog tsuas yog yooj yim mus ua paug rau lub hwj chim daim phiaj, ncaj qha cuam tshuam rau ib txwm ua hauj lwm ntawm lwm yam khoom siv hluav taws xob, tab sis kuj yog ib qho yooj yim mus ua hauj lwm. tsim electromagnetic pollution nyob rau hauv qhov chaw nkag, ua rau cov teeb meem electromagnetic compatibility (EMC) ntawm high-frequency switching fais fab mov. Kab lus no tsom mus rau kev txheeb xyuas qhov cuam tshuam ntawm electromagnetic cuam tshuam tshaj tus qauv hauv 1200W (24V / 50A) high-frequency switching power supply module siv nyob rau hauv railway signal power supply screens, thiab qhia txog kev txhim kho.
Kev cuam tshuam ntawm electromagnetic cuam tshuam los ntawm cov khoom siv hluav taws xob ntau zaus tuaj yeem muab faib ua ob pawg: kev cuam tshuam thiab hluav taws xob cuam tshuam. Cov kev cuam tshuam tau nthuav tawm los ntawm AC lub zog hluav taws xob nrog cov zaus qis dua 30MHz; Radiation cuam tshuam propagates los ntawm qhov chaw, nrog ntau zaus ntawm 30 txog 1000MHz.
Qhov kev txiav txim siab zoo tshaj plaws tsim tawm thaum lub sij hawm rectification txheej txheem ntawm lub rectifier yuav ua rau cov conduction thiab hluav taws xob cuam tshuam nyob rau hauv txoj kab hluav taws xob.
Hloov fais fab transistors ua haujlwm hauv high-frequency conduction thiab txiav tawm lub xeev. Txhawm rau kom txo tau cov khoom ploj, txhim kho hluav taws xob ceev thiab tag nrho kev txuag hluav taws xob, qhib nrawm nrawm thiab nrawm dua, feem ntau yog ob peb microconds. Lub tshuab hluav taws xob hloov pauv qhib thiab kaw ntawm qhov nrawm no, tsim cov hluav taws xob hluav taws xob thiab hluav taws xob tam sim no, uas yuav tsim kom muaj kev sib tw siab thiab high-voltage peak harmonics thiab electromagnetic cuam tshuam ntawm qhov chaw thiab AC input kab.
Nyob rau tib lub sij hawm thaum lub high-frequency transformer T1 ua lub zog transformer, nws generates alternating electromagnetic teb, radiating electromagnetic tsis nyob rau hauv qhov chaw, tsim hluav taws xob cuam tshuam. Qhov faib inductance thiab capacitance ntawm lub transformer tsim oscillations, uas yog txuas mus rau AC input Circuit Court los ntawm kev faib capacitance ntawm thawj theem ntawm transformer, tsim conductive cuam tshuam.
Thaum cov zis hluav taws xob qis qis, qhov tso zis hluav taws xob rectifier diode ua haujlwm nyob rau hauv lub xeev hloov pauv siab thiab tseem yog qhov cuam tshuam ntawm electromagnetic cuam tshuam.
Vim yog cov kab mob parasitic inductance thiab junction capacitance ntawm diode cov hlau lead, nrog rau kev cuam tshuam ntawm kev rov qab los tam sim no, nws ua haujlwm ntawm high voltage thiab tam sim no hloov pauv. Lub sijhawm ntev ntawm lub diode rov qab lub sijhawm, qhov cuam tshuam ntawm qhov siab tshaj plaws tam sim no, thiab qhov muaj zog ntawm cov teeb liab cuam tshuam, uas ua rau muaj kev cuam tshuam ntau zaus attenuation oscillation, uas yog qhov sib txawv ntawm qhov kev cuam tshuam kev cuam tshuam.
Tag nrho cov hluav taws xob hluav taws xob tsim hluav taws xob tau xa mus rau cov khoom siv hluav taws xob sab nraud los ntawm cov hlau hlau xws li cov kab hluav taws xob, cov kab teeb liab, thiab cov xaim hauv av, ua rau muaj kev cuam tshuam kev cuam tshuam. Radiated cuam tshuam yog tshwm sim los ntawm kev cuam tshuam cov teeb liab tawm los ntawm cov xov hlau thiab cov khoom siv los yog los ntawm kev sib txuas ntawm cov xov hlau uas ua raws li cov kav hlau txais xov.
