Electromagnetic Compatibility Design Scheme ntawm High Frequency Stabilized Power Supply
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 yog tsis ua hauj lwm zoo, nws yuav tsis tsuas yooj yim 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 yooj yim tsim electromagnetic. Cov pa phem rau hauv qhov chaw, ua rau muaj teeb meem Electromagnetic Compatibility (EMC) ntawm zaus hloov cov khoom siv hluav taws xob. Daim ntawv no tsom mus rau kev tsom xam ntawm kev cuam tshuam ntawm electromagnetic cuam tshuam ntau tshaj li tus qauv ntawm 1200W (24V / 50A) high-frequency switching power supply module siv nyob rau hauv lub railway signal power supply screen, thiab qhia txog kev txhim kho.
Lub electromagnetic cuam tshuam tsim los ntawm high-frequency switching fais fab mov tuaj yeem muab faib ua ob pawg: kev cuam tshuam kev cuam tshuam thiab hluav taws xob cuam tshuam. Lub conduction cuam tshuam propagates los ntawm AC fais fab mov, thiab zaus qis dua 30MHz; Cov hluav taws xob cuam tshuam cuam tshuam los ntawm qhov chaw, thiab qhov zaus yog 30-1000MHz.
Kev soj ntsuam ntawm Electromagnetic Disturbance Source of High Frequency Switching Power Supply
Lub rectifier, lub hwj chim raj Q1 nyob rau hauv Circuit Court, lub hwj chim raj Q2 ~ Q5, siab zaus transformer T1, thiab tso zis rectifier diodes D1 ~ D2 nyob rau hauv lub Circuit Court nyob rau hauv daim duab 1b yog lub ntsiab qhov chaw ntawm electromagnetic cuam tshuam thaum lub siab zaus hloov fais fab mov ua hauj lwm. . Tshwj xeeb tsom xam raws li hauv qab no.
Qhov kev txiav txim siab sib haum xeeb tsim los ntawm cov txheej txheem rectification ntawm lub rectifier yuav ua rau muaj kev cuam tshuam thiab cuam tshuam los ntawm txoj kab hluav taws xob.
Lub tshuab hluav taws xob hloov hluav taws xob ua haujlwm nyob rau hauv high-frequency on and off state. Txhawm rau txo qis kev hloov pauv, txhim kho lub zog ceev thiab tag nrho cov txiaj ntsig ntawm cov khoom siv hluav taws xob, lub raj xa hluav taws xob tau qhib thiab tawm sai dua thiab nrawm dua, feem ntau hauv ob peb microseconds, thiab lub raj hloov pauv yuav siv sij hawm tig rau thiab tawm ntawm qhov zoo li no. ceev cov ntaub ntawv surge voltage thiab surge tam sim no, uas yuav tsim high-frequency thiab high-voltage ncov harmonics, thiab tsim electromagnetic cuam tshuam rau qhov chaw thiab AC input kab.
Thaum lub high-frequency transformer T1 ua lub zog hloov dua siab tshiab, nws tsim ib qho kev sib hloov electromagnetic teb thiab radiates electromagnetic nthwv dej rau hauv qhov chaw, tsim hluav taws xob cuam tshuam. Qhov faib inductance thiab capacitance ntawm transformer oscillate, thiab yog txuas mus rau AC input voj los ntawm kev faib capacitance ntawm thawj theem thiab theem nrab ntawm lub transformer, tsim kev cuam tshuam kev 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, uas kuj yog qhov cuam tshuam ntawm electromagnetic cuam tshuam.
Vim yog cov kab mob parasitic inductance ntawm cov hlau lead ntawm lub diode, qhov muaj nyob ntawm qhov sib txuas capacitance thiab cuam tshuam ntawm qhov rov qab los tam sim no, nws ua haujlwm ntawm qhov siab ntawm qhov voltage thiab tam sim no hloov. Lub sijhawm rov qab rov qab ntev dua ntawm lub diode, qhov cuam tshuam ntau dua ntawm lub ncov tam sim no. , 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 hom kev cuam tshuam kev cuam tshuam.
Tag nrho cov teeb liab hluav taws xob tsim hluav taws xob no tau xa mus rau sab nraud hluav taws xob los ntawm cov hlau xaim xws li cov kab hluav taws xob, cov kab teeb liab, thiab cov kab hauv av los tsim kev cuam tshuam kev cuam tshuam. Radiated cuam tshuam yog tshwm sim los ntawm kev cuam tshuam cov teeb liab radiating los ntawm conductors thiab pab kiag li lawm los yog los ntawm interconnecting kab ua raws li antennas.
