Chu ky nhiet la ke sat nguam cua cum thanh dan: thiet ke va kiem tra cho tuoi tho dai

Chu ky nhiet so voi power cycling: biet su khac biet

Hai phep thu van dong cac phan khac nhau cua cum. Chu ky nhiet thay doi nhiet do cua toan module hoac cum giua cac diem co dinh (vi du tru 40 den cong 125 do theo IEC 60068-2-14) va lam ung suat cap dong goi: cong day de, tac lop hang solder cua de, nut mold va tang dien tro tong. Power cycling nguoc lai chi lam nong cac thiet bi tich cuc bang tu lam nong, soc nhiet cuc bo nhanh, va lam ung suat cac giao dien cap chip: die-attach va day bond. Trong cum thanh dan, tuong duong la phan biet giua chu ky moi truong (toan cum, tam cach dien, phan cung) va chu ky tai (lam nong bang dong cua dan dan va ket noi).

Voi mot thanh dan dien tu cong suat ca hai deu quan trong: tam cach dien chiu chu ky moi truong trong tu ngoai troi, trong khi ket noi chiu chu ky tai moi lan converter hoat dong. Huong dan rung va moi noi bulong trinh bay phia co hoc; huong dan nay trinh bay phia nhiet cua cung cau chuyen do tin cay.

Lech CTE: co che goc

Moi vat lieu trong cum thanh dan gian no theo nhiet do khac nhau. Dong gian khoang 17 ppm/K, nhom khoang 23 ppm/K, mang PET va dielectric epoxy lon hon mot bac trong mat phang hoac qua be day tuy cau tao, va phan cung thep khoang 12 ppm/K. Khi cum nong len, moi lop muon lon mot luong khac nhau, va cac giao dien chiu su khac biet nhu ung suat cat. Qua hang nghin chu ky, ung suat do tich luy nhu tu bien, rong khi, vet nut va tac lop trong cac lop hang va keo dinh.

Tai lieu IEEE ve moi hang solder cua module IGBT ro rang ve co che: do lech CTE giua cac lop ke nhau trong module da lop, ung suat nhiet-co hoc qua muc xuat hien o lop hang, va moi hang tich luy giua de va de DCB duoi dang tu bien, rong khi, vet nut hoac tac lop. Phien ban thanh dan cua cung vat ly la moi noi hang hoac keo dinh giua lop dong va dielectric, va giua tai dau noi va dan dan.

Vet nut bat dau dau: quy tac diem nong nhat

Met moi la hien tuong cuc bo va bat dau noi nhiet do cao nhat. Trong module IGBT, do la hang truc tiep duoi tam chip: nhiet chay qua chip xuong hang, va vung nong nhat va ung suat nhat nut truoc. Trong cum thanh dan, tuong duong la ket noi dau noi (noi mat do dong tap trung), cac giao dien canh nguon nhiet (dau noi module, ngan dien tro) va cac vung tam cach dien tren giao cua thanh dan noi mat do ton that dat dinh.

He qua thiet ke la do tin cay duoc quyet dinh tai diem nong, khong phai nhiet do trung binh. Mot mo phong nhiet chi bao cao trung binh 40 do se che giau giao dien dau noi 95 do noi vet nut se bat dau. Huong dan thiet ke quan ly nhiet cua chung toi cho thay cach xac dinh diem nong bang mo phong truoc nguyen mau dau tien va lam mat cac giao dien se met moi truoc.

Moi noi hang: mat xich de met moi

Moi noi hang cua thanh dan, tai dau noi, moi noi lop cach dien, ket noi thanh dan-dau noi, la noi met moi kinh dien. Hang khong chi co hanh vi khac hang thiec-chi truyen thong: cung hon va tu bien khac, va su thoai hoa dien tro nhiet khi hang nut thuong theo duong cong khac. Trinh tu hong nhat quan: vet nut vi mo xuat hien o mep giao dien, lon duoi chu ky, tang dien tro nhiet cuc bo, lam tang nhiet do moi noi va tang toc chu ky tiep theo, mot vong lap phan hoi duong ket thuc o ket noi ho hoac nong.

Bang chung kiem tra den tu nghien cuu power cycling tren module IGBT, noi dien ap collector-emitter dan thong (V_CE_ON) va dien ap thuan (V_F) duoc dan xuat nhu chi so tieu chuan giam sat thoai hoa hang. Tuong duong trong thanh dan la troi dien tro tiep xuc trong moi noi bulong va tang tro khang nhiet trong giao dien hang. Giam sat ca hai chuyen su co thanh lich bao tri du dinh.

Day bond va tuong tu moi noi hang

Trong module IGBT, day bond boc va vet nut chan la che do mai mon thong tri khac: day met moi tai chan moi noi, noi nhom chuyen tu day sang pad. Tuong tu trong thanh dan la moi noi hang (sieu am, laser hoac TIG) va tai hang cua thanh dan pin. Hang tap trung ung suat tai ngon hang; duoi chu ky nhiet, vet nut khoi dau do va lon qua vung hang. Huong dan han noi trinh bay thiet ke moi noi; thong diep do tin cay la hinh hoc hang, khong chi do ben cua no, quyet dinh tuoi tho chu ky.

Cac bien phap thiet ke giong nhung gi bao ve day bond: giu day nhiet do chu ky nho (lam mat giao dien), dua moi noi ra khoi gradient nhiet manh nhat va chon hinh hoc moi noi voi ban kinh lon de ung suat phan bo thay vi tap trung.

Moi noi bulong: long duoi chu ky

Moi noi bulong cua thanh dan long duoi chu ky nhiet, ngay ca khi mo-men sieu hoan hao tai lap dat. Co che la tu bien: pad dong mo va chay nhe o nhiet do cao, luc sieu giam, dien tro tiep xuc tang, moi noi chay nong hon va chu ky tiep theo lam long them. Trong moi truong co rung, ca hai co che ket hop, long nhiet cong long co hoc, nen thiet ke moi noi kiem tra rung va thiet ke nhiet chia se cung phep thu moi noi.

Cac hieu chinh thuc te: vong deo hoac vong bi giu luc trong khi dong chay; quy trinh sieu lai sau mua nhiet dau tien; be mat tiep xuc lop phu giu giao dien khong oxy hoa; va tai lieu mo-men noi bao tri biet moi noi nen nhu the nao. Mot moi noi bulong la hang muc bao tri, khong phai chi tiet lap roi quen; ke hoach do tin cay phai noi khi nao no duoc kiem tra lai.

Tam cach dien: tac lop vi mo va met moi mep

Cau tao cach dien chinh no chu ky: lop dong gian chong lai dielectric, va qua hang nghin chu ky moi lien ket co the tac lop vi mo o mep tam. Nguy hiem khong phai ket cau, ma la dien: mep tac lop tro thanh rong khi, va rong khi trong tam cach dien dien ap cao la diem phong dien bo phan. Dien ap khoi dau phong dien bo phan giam khi rong khi lon, va su co xuat hien nhu ro dien hoac phong dien nhieu nam sau lap dat. Vi vay bim mep va cach dien khong rong khi la dac tinh do tin cay, khong phai trang tri.

Cho cau tao thanh dan cach dien nhieu lop, chat luong cach dien the hien trong thu chu ky nhiet: sau 1.000 chu ky, tam tot khong cho thay thay doi dien ap khoi dau phong dien bo phan, trong khi tam trung binh cho thay troi do duoc. Huong dan thiet ke khong phong dien bo phan cua chung toi trinh bay vat ly cua rong khi va mep, va huong dan kiem tra cach dien cac phep do bat troi.

Tieu chuan va phuong phap thu

Thuc don kiem tra do tin cay cho cum thanh dan theo cac tieu chuan nganh dien tu cong suat da dung. Chu ky nhiet do theo IEC 60068-2-14 voi toc do, thoi gian giu va so chu ky xac dinh; power cycling theo phuong phap duoc kiem dinh trong tai lieu IEEE voi bien do nhiet do moi noi hoac ket noi lam bien kiem soat; chu ky am (IEC 60068-2-30 hoac IEC 60068-2-38) noi ap dung van hanh ngoai troi; va rung theo IEC 60068-2-6/2-64 cho van chuyen va moi truong van hanh. Ke hoach thu phai khai bao tieu chi hong, bao nhieu troi dien tro tiep xuc hoac thay doi dien ap khoi dau phong dien bo phan la hong, truoc khi chu ky dau tien chay.

Danh gia IEEE ve power cycling ghi nhan rang phep thu power cycling du bao tuoi tho thanh phan trong converter cong suat va mach do V_CE_ON va V_F la duong tieu chuan giam sat tinh trang trong thu. Cung logic ap dung cho chuong trinh thanh dan: xac dinh chi so, do no trong thu va cong bo duong cong voi bang thong so.

Quy tac thiet ke keo dai tuoi tho chu ky

Nam quy tac thiet ke thong tri do tin cay duoi chu ky nhiet. Thu nhat, toi thieu hoa day nhiet do chu ky tai cac giao dien: moi lan giam 10 do gan nhu nhan doi tuoi tho met moi cua nhieu vat lieu, nen lam mat moi noi la bien phap do tin cay, khong chi an ui derating. Thu hai, bu tru he so noi co the: noi nhom tren thanh dan nhom, dong tren dong va phan cung nam giua CTE cua cac ban phan no giu. Thu ba, phan bo ung suat: ban kinh lon, dien tich tiep xuc lon hon, bulong phan bo. Thu tu, bao ve giao dien: lop phu khong oxy hoa, bim giu am khoi moi noi. Thu nam, lap ke hoach kiem tra: moi noi tiep can duoc, mo-men tai lieu va diem giam sat noi dien tro hoac nhiet do do duoc trong van hanh.

Danh sach kiem tra DFM cua chung toi chua cac diem lien quan do tin cay, va huong dan thiet ke cac quy tac layout; ca hai cung nhau cho cap ban ve cua bai viet nay.

Kiem tra do tin cay nhu yeu cau mua hang

Nguoi mua thanh dan cho ung dung nhieu chu ky, keo EV, container lu tru, truyen dong cong nghiep, gondola gio, phai dua bang chung do tin cay vao RFQ: ke hoach thu chu ky nhiet, so chu ky muc tieu, tieu chi hong va chi so giam sat. Mot nha cung cap co the cho thay du lieu 1.000 chu ky voi dien tro tiep xuc on dinh bao gia khac nha cung cap chi trinh danh muc tinh. Huong dan danh gia nha cung cap can nhung bang chung nay canh gia va thoi gian.

Cho chuong trinh EV va o to, yeu cau da ton tai qua ky vong dinh chat kieu AEC; cho ung dung cong nghiep va lu tru, ky luat dang bat kip. Nguoi mua them no bay gio la nguoi tranh duoc nam bao hanh.

Giam sat trong van hanh: troi dien tro va nhiet do

Chi so dang tin cay nhat cua moi noi thanh dan dang met moi la su troi: dien tro tiep xuc tang, nhiet do moi noi tang so voi duong co so hoac dien ap khoi dau phong dien bo phan giam trong tam cach dien dien ap cao. Ca ba deu do duoc trong van hanh voi moc thiet ke dung: pad cam bien tren thanh dan, moi noi tiep can, diem do phong dien bo phan. Chuong trinh chat luong dang sau don hang thanh dan phai bao gom huong dan giam sat, khong chi chung chi kiem tra.

Trong thuc te, quet hong ngoai tai khoi dong va moi lan bao tri hang nam bat som cac moi noi nong; do dien tro bat som hon nhung can tiep can. Ket hop, quet khoi dong, quet hang nam va kiem tra mo-men sau mua nhiet dau tien, la phien ban re cua giam sat tinh trang bat 90 phan tram su co chu ky truoc khi chung la su co.

Mat do dong dien va vong tu hoat nhiet

Chu ky nhiet trong thanh dan duoc thuc day boi hai nguon nhiet: chu ky moi truong va chu ky tai. Chu ky tai la chu ky nha thiet ke kiem soat, va no bi chi phoi boi mat do dong dien. Tai moi noi dau, dong dien don vao dien tich tiep xuc; ton that ket qua lam nong moi noi; tang nhiet lam tang dien tro tiep xuc (dien tro suat cua dong tang theo nhiet do); va moi noi nong hon tan nhieu ton that hon, mot vong phan hoi chay nong hon thanh dan xung quanh. Mot moi noi tinh cho tang 30°C o trung binh thanh dan co the chay o 60°C tai tiep xuc, chinh la bien do nhiet lam moi giao dien.

Cac tai lieu kha nang mang dong va chia dong de cap phia dinh muc; phia do tin cay la cung phep tinh nhin tu giao dien. Neu dien tich tiep xuc qua nho, khong lop ma hay moment nao cuu moi noi khoi moi chu ky.

Nghien cuu truong hop: su co thanh dan rack luu tru

Mot mo hinh hien truong lap di lap lai trong cac rack luu tru nang luong minh hoa co che. Cac thanh dan rack tinh cho tang 30°C o 25°C moi truong chay tot nam dau; nam thu hai, vai dau noi bulong cho thay nhiet do cao o lan quet nam; den nam thu ba, cac dau noi do duoc siet lai va mot so tai noi duoc thay. Nguyen nhan goc la chu ky hang ngay cua container: sac ban ngay lam nong thanh dan len 55-65°C, tat ban dem lam lanh xuong 20°C, va bien do 40°C lap lai hang ngay, khoang 1.400 chu ky den cuoi nam thu hai, du de noi long mot moi ghep M8 duoc siet o muc toi thieu.

Bien phap khac phuc la su ket hop ma huong dan nay khuyen nghi: dien tich tiep xuc lon hon, vong dem lo xo giu luc kep, siet lai tai bao tri nam mot, va duong co so van hanh de do troi nhin thay. Bai viet ve lien ket DC luu tru de cap phia dien; bai hoc do tin cay la chu ky hang ngay la mot thu nghiem chay bat ke san pham co duoc dinh chung cho no hay khong.

Ket noi nhom va quan ly CTE

Nhom trinh bay mot truong hop CTE dac biet: no gian no khoang 23 ppm/K so voi 17 ppm/K cua dong va 12 ppm/K cua thep, va lop oxit cua no tai hinh thanh tai moi giao dien bi xao tron. Mot moi noi nhom-dong duoi chu ky nhiet thay su gian no khac biet cong van de oxit, va giao dien moi nhanh hon moi noi kim loai tuong dong. Noi nhom xuat hien tren cac duong di khong quan trong hoac noi trong luong quan trong, thiet ke nen quan ly su lech: cac mieng chuyen tiep hai kim loai, ket noi lo xo, dien tich tiep xuc lon hon, va lop ma ngan tai oxy hoa.

Tai lieu dong so voi nhom cua chung toi de cap su danh doi o cap dan; quy tac do tin cay la moi giao dien kim loai khac loai la mot hang muc bao tri voi khoang cach kiem tra xac dinh. Lua chon lop ma, rao can nickel, lop hoan thien thiec, la mot phan cua quan ly CTE va an mon tai cung moi noi.

Dinh chung o cap he thong so voi cap thanh phan

Thu nghiem o cap thanh phan chung minh chi tiet; dieu kien o cap he thong quyet dinh che do van hanh thuc. Mot thanh dan co the vuot 1.000 chu ky o bien do 60°C tren ban thu va van hong trong container noi bien do la 45°C nhung co rung, hoac noi do am moi truong tang toc su suy giam giao dien. Dinh chung do tin cay vi vay nen ket hop thu nghiem nhiet voi dieu kien he thong thuc: ho so nhiet cua tu, rung lap dat va lich bao tri. Cac huong dan ve rung va do am ngoai troi de cap hai chan con lai cua cung tam giac dinh chung.

Voi nguoi mua, yeu cau la mot ke hoach thu nghiem ket hop thay vi ba chung nhan rieng: chu ky nhiet tren cum lap dat nhu duoc lap, voi do am noi ap dung van hanh ngoai troi, va rung noi ung dung yeu cau. Cac chi tiet qua thu rieng va hong cung nhau la khoang trong dinh chung pho bien nhat cua nganh.

Uoc tinh tuoi tho: tu chu ky den nam

Do tin cay cuoi cung la cau hoi lich: cum lap song duoc bao nhieu nam phuc vu? Cong thuc tat cua ky thuat la moi quan he Coffin-Manson, tuoi tho moi tinh theo bien do nhiet voi luy thua, dien hinh khoang am 2 den am 3 cho moi han. Dieu do lam bien do thanh bien so chi phoi: giam bien do 60°C xuong 45°C co the gan nhu nhan doi hoac nhan ba tuoi tho, va giam xuong 30°C co the nhan nhieu lan. Cung vat ly lam quy tac 10°C huu ich cung lam cho viec dau tu lam mat de chung minh.

Cho mot chuong trinh thanh dan tuy chinh, uoc tinh tuoi tho nen duoc khai bao voi gia dinh bien do: thiet ke cho 5.000 chu ky o bien do 50°C la mot tuyen bo kiem tra duoc, trong khi thiet ke cho 20 nam la hy vong khong co chu ky van hanh. Cac tai lieu ve ngan mach va nhiet cua chung toi cung nhau dinh nghia toan bo che do co hoc ma uoc tinh tuoi tho bao phu.

Tai lieu va ho so do tin cay

Ho so do tin cay di kem mot don hang thanh dan nen chua: ke hoach thu nghiem, so chu ky va tieu chi hong, cac chi so giam sat (dien tro tiep xuc, nhiet do, khoi dau PD), uoc tinh tuoi tho voi gia dinh bien do, va cac khuyen nghi bao tri, khoang cach siet lai, diem kiem tra, tieu chi thay the. Nguoi mua nhan duoc ho so nay co the dat thanh dan vao lich bao tri thay vi phat hien su moi tren hien truong.

Trang chat luong cua chung toi mo ta viec kiem soat thu nghiem va tai lieu dung sau ho so, va trang tham quan nha may cho thay thiet bi thu nghiem chu ky. Ky luat don gian: khai bao che do, thu nghiem che do, va cong bo nhung gi da thu nghiem. Do la toan bo hop dong do tin cay giua nha cung ung thanh dan va nha che tao converter.

FAQ: chu ky nhiet va do tin cay thanh dan

Thanh dan nen song sot bao nhieu chu ky? Phu thuoc ung dung: truyen dong cong nghiep dien hinh chi dinh hang tram den hang nghin chu ky; lu tru o to va noi luoi co the yeu cau hang nghin voi tieu chi hong xac dinh. Moi noi bulong hay hang tot hon duoi chu ky? Hang khong long nhung tap trung ung suat tai ngon; bulong co the sieu lai nhung long do tu bien. Cau tra loi dung phu thuoc bien do nhiet do va ke hoach bao tri. Lam sao biet thanh dan cua toi dang met moi? Do troi dien tro tiep xuc hoac nhiet do moi noi so voi duong co so khoi dong. Thiet ke co the sua van de chu ky khong? Gan nhu luon: lam mat giao dien va phan bo ung suat la hai thay doi hieu qua nhat. Lien he doi ngu ky thuat cua chung toi de danh gia do tin cay cho layout cua ban.