{"id":6226,"date":"2018-11-30T08:34:55","date_gmt":"2018-11-30T08:34:55","guid":{"rendered":"https:\/\/hocvienit.vn\/?p=6226"},"modified":"2024-11-06T11:32:32","modified_gmt":"2024-11-06T04:32:32","slug":"tim-hieu-ve-dong-dien-xoay-chieu","status":"publish","type":"post","link":"https:\/\/hocvienit.vn\/?p=6226","title":{"rendered":"Nh\u1eefng \u0111i\u1ec1u c\u1ea7n bi\u1ebft v\u1ec1 d\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u"},"content":{"rendered":"

D\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u, nh\u01b0 t\u00ean g\u1ecdi c\u1ee7a n\u00f3, l\u00e0 d\u00f2ng \u0111i\u1ec7n c\u00f3 chi\u1ec1u v\u00e0 c\u01b0\u1eddng \u0111\u1ed9 thay \u0111\u1ed5i li\u00ean t\u1ee5c theo th\u1eddi gian. Ngu\u1ed3n \u0111i\u1ec7n trong gia \u0111\u00ecnh ch\u00fang ta s\u1eed d\u1ee5ng h\u00e0ng ng\u00e0y ch\u00ednh l\u00e0 d\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u. Tuy nhi\u00ean, c\u00e1c thi\u1ebft b\u1ecb \u0111i\u1ec7n t\u1eed nh\u01b0 laptop, \u0111i\u1ec7n tho\u1ea1i l\u1ea1i ho\u1ea1t \u0111\u1ed9ng d\u1ef1a tr\u00ean d\u00f2ng \u0111i\u1ec7n m\u1ed9t chi\u1ec1u (DC)<\/a>. V\u1eady l\u00e0m th\u1ebf n\u00e0o \u0111\u1ec3 chuy\u1ec3n \u0111\u1ed5i t\u1eeb AC sang DC? H\u00e3y c\u00f9ng H\u1ecdc vi\u1ec7n iT t\u00ecm hi\u1ec3u ngay trong b\u00e0i vi\u1ebft n\u00e0y nh\u00e9!<\/p>\n

\"Nh\u1eefng
Nh\u1eefng \u0111i\u1ec1u c\u1ea7n bi\u1ebft v\u1ec1 d\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u<\/figcaption><\/figure>\n

D\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u l\u00e0 g\u00ec?<\/span><\/h2>\n

Ch\u00fang ta c\u00f3 \u0111\u1ecbnh ngh\u0129a d\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u nh\u01b0 sau: <\/span>D\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u<\/span><\/i> l\u00e0 d\u00f2ng \u0111i\u1ec7n<\/a> c\u00f3 chi\u1ec1u v\u00e0 gi\u00e1 tr\u1ecb bi\u1ebfn \u0111\u1ed5i \u00a0theo th\u1eddi gian, nh\u1eefng thay \u0111\u1ed5i n\u00e0y th\u01b0\u1eddng tu\u1ea7n ho\u00e0n theo m\u1ed9t chu k\u1ef3 nh\u1ea5t \u0111\u1ecbnh. D\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u th\u01b0\u1eddng \u0111\u01b0\u1ee3c t\u1ea1o ra t\u1eeb c\u00e1c m\u00e1y ph\u00e1t \u0111i\u1ec7n xoay chi\u1ec1u ho\u1eb7c bi\u1ebfn \u0111\u1ed5i t\u1eeb ngu\u1ed3n \u0111i\u1ec7n m\u1ed9t chi\u1ec1u b\u1edfi m\u1ed9t m\u1ea1ch \u0111i\u1ec7n t\u1eed th\u01b0\u1eddng g\u1ecdi l\u00e0 b\u1ed9 ngh\u1ecbch l\u01b0u d\u00f9ng c\u00e1c thyristor.<\/span><\/p>\n

Trong k\u1ef9 thu\u1eadt \u0111i\u1ec7n, ngu\u1ed3n xoay chi\u1ec1u \u0111\u01b0\u1ee3c vi\u1ebft t\u1eaft ti\u1ebfng anh l\u00e0 AC (Alternating Current) v\u00e0 \u0111\u01b0\u1ee3c k\u00fd hi\u1ec7u b\u1edfi h\u00ecnh d\u1ea5u <\/span>~<\/strong><\/p>\n

Trong m\u1ea1ch \u0111i\u1ec7n \u0111i\u1ec7n t\u1eed, s\u00f3ng sin \u0111\u01b0\u1ee3c d\u00f9ng \u0111\u1ec3 \u00e1m ch\u1ec9 \u0111i\u1ec7n xoay chi\u1ec1u \u0111\u1eb7t tr\u00ean nh\u1eefng linh ki\u1ec7n \u0111i\u1ec7n t\u1eed v\u00ec s\u00f3ng Sin l\u00e0 m\u1ed9t d\u1ea1ng s\u00f3ng tu\u1ea7n ho\u00e0n \u0111i\u1ec1u h\u00f2a.<\/span><\/p>\n

Chu k\u1ef3 v\u00e0 t\u1ea7n s\u1ed1 c\u1ee7a d\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u<\/span><\/h3>\n

Chu k\u1ef3 c\u1ee7a d\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u k\u00fd hi\u1ec7u l\u00e0 T. L\u00e0 kho\u1ea3ng th\u1eddi gian m\u00e0 \u0111i\u1ec7n xoay chi\u1ec1u l\u1eb7p l\u1ea1i v\u1ecb tr\u00ed nh\u01b0 c\u0169. Chu k\u1ef3 c\u1ee7a d\u00f2ng xoay chi\u1ec1u \u0111\u01b0\u1ee3c t\u00ednh b\u1eb1ng gi\u00e2y (s).<\/span><\/p>\n

T\u1ea7n s\u1ed1 \u0111i\u1ec7n xoay chi\u1ec1u l\u00e0 s\u1ed1 l\u1ea7n l\u1eb7p l\u1ea1i tr\u1ea1ng th\u00e1i nh\u01b0 c\u0169 c\u1ee7a d\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u trong m\u1ed9t gi\u00e2y k\u00fd hi\u1ec7u l\u00e0 F. \u0110\u01a1n v\u1ecb c\u1ee7a t\u1ea7n s\u1ed1 l\u00e0 Hz.<\/span><\/p>\n

C\u00f4ng th\u1ee9c: <\/span><\/p>\n

F=1\/T<\/strong><\/p>\n

Pha c\u1ee7a d\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u<\/span><\/h3>\n

Khi nh\u1eafc \u0111\u1ebfn pha c\u1ee7a d\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u, ng\u01b0\u1eddi ta th\u01b0\u1eddng nh\u1eafc t\u1edbi m\u1ed1i quan h\u1ec7 so s\u00e1nh gi\u1eefa 2 d\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u c\u00f3 c\u00f9ng m\u1ed9t t\u1ea7n s\u1ed1. C\u00f3 3 tr\u1ea1ng th\u00e1i quan h\u1ec7 gi\u1eefa 2 d\u00f2ng xoay chi\u1ec1u nh\u01b0 sau:<\/span><\/p>\n

– Hai d\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u c\u00f9ng pha l\u00e0 2 d\u00f2ng \u0111i\u1ec7n c\u00f3 c\u00e1c th\u1eddi \u0111i\u1ec3m \u0111i\u1ec7n \u00e1p c\u00f9ng t\u0103ng v\u00e0 c\u00f9ng gi\u1ea3m nh\u01b0 nhau.<\/span><\/p>\n

\"Nh\u1eefng
Nh\u1eefng \u0111i\u1ec1u c\u1ea7n bi\u1ebft v\u1ec1 d\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u<\/figcaption><\/figure>\n

– Hai d\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u l\u1ec7ch pha l\u00e0 hai d\u00f2ng \u0111i\u1ec7n c\u00f3 th\u1eddi \u0111i\u1ec3m \u0111i\u1ec7n \u00e1p t\u0103ng gi\u1ea3m l\u1ec7ch nhau.<\/span><\/p>\n

– D\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u ng\u01b0\u1ee3c pha l\u00e0 d\u00f2ng \u0111i\u1ec7n c\u00f3 pha l\u1ec7ch nhau 180 \u0111\u1ed9. Khi d\u00f2ng \u0111i\u1ec7n n\u00e0y t\u0103ng th\u00ec d\u00f2ng \u0111i\u1ec7n kia s\u1ebd gi\u1ea3m v\u00e0 ng\u01b0\u1ee3c l\u1ea1i.<\/span><\/p>\n

Bi\u00ean \u0111\u1ed9 c\u1ee7a d\u00f2ng xoay chi\u1ec1u l\u00e0 gi\u00e1 tr\u1ecb \u0111i\u1ec7n \u00e1p \u0111\u1ec9nh c\u1ee7a d\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u. Bi\u00ean \u0111\u1ed9 n\u00e0y th\u01b0\u1eddng cao h\u01a1n \u0111i\u1ec7n \u00e1p m\u00e0 ta \u0111o \u0111\u01b0\u1ee3c t\u1eeb c\u00e1c \u0111\u1ed3ng h\u1ed3.<\/span><\/p>\n

Gi\u00e1 tr\u1ecb hi\u1ec7u d\u1ee5ng<\/span><\/h3>\n

Gi\u00e1 tr\u1ecb hi\u1ec7u d\u1ee5ng l\u00e0 gi\u00e1 <\/span>tr\u1ecb \u0111o \u0111\u01b0\u1ee3c t\u1eeb c\u00e1c \u0111\u1ed3ng h\u1ed3 v\u00e0 c\u0169ng l\u00e0 gi\u00e1 tr\u1ecb \u0111i\u1ec7n \u00e1p \u0111\u01b0\u1ee3c ghi tr\u00ean gi\u1eafc c\u1eafm ngu\u1ed3n c\u1ee7a c\u00e1c thi\u1ebft b\u1ecb \u0111i\u1ec7n t\u1eed.<\/span><\/p>\n

V\u00ed d\u1ee5: ngu\u1ed3n 220V AC m\u00e0 ta \u0111ang s\u1eed d\u1ee5ng ch\u00ednh l\u00e0 ch\u1ec9 gi\u00e1 tr\u1ecb hi\u1ec7u d\u1ee5ng, th\u1ef1c t\u1ebf bi\u00ean \u0111\u1ed9 \u0111\u1ec9nh c\u1ee7a \u0111i\u1ec7n \u00e1p 220V AC kho\u1ea3ng 220V x 1,4 l\u1ea7n = kho\u1ea3ng 300V.<\/span><\/p>\n

C\u00f4ng su\u1ea5t c\u1ee7a d\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u<\/span><\/h3>\n

C\u00f4ng su\u1ea5t c\u1ee7a d\u00f2ng xoay chi\u1ec1u l\u00e0 m\u1ed9t \u0111\u1ea1i l\u01b0\u1ee3ng ph\u1ee5 thu\u1ed9c v\u00e0o c\u01b0\u1eddng \u0111\u1ed9, \u0111i\u1ec7n \u00e1p v\u00e0 \u0111\u1ed9 l\u1ec7ch pha gi\u1eefa 2 \u0111\u1ea1i l\u01b0\u1ee3ng tr\u00ean. C\u00f4ng su\u1ea5t \u0111\u01b0\u1ee3c t\u00ednh b\u1edfi c\u00f4ng th\u1ee9c sau:<\/span><\/p>\n

P=UIcos\u03b1<\/strong><\/p>\n

Trong \u0111\u00f3: U l\u00e0 \u0111i\u1ec7n \u00e1p, I l\u00e0 d\u00f2ng \u0111i\u1ec7n v\u00e0 \u03b1 l\u00e0 g\u00f3c l\u1ec7ch pha gi\u1eefa U v\u00e0 I<\/span><\/p>\n

\u01afu \u0111i\u1ec3m c\u1ee7a d\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u<\/span><\/h3>\n

V\u1eady d\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u \u0111\u00f3ng g\u00f3p nh\u1eefng l\u1ee3i \u00edch g\u00ec v\u00e0 v\u00ec sao ng\u01b0\u1eddi ta l\u1ea1i s\u1eed d\u1ee5ng lo\u1ea1i \u0111i\u1ec7n n\u00e0y? Trong xe h\u01a1i, d\u00f2ng \u0111i\u1ec7n n\u1ea1p v\u00e0o trong \u1eafc quy do m\u00e1y ph\u00e1t \u0111i\u1ec7n xoay chi\u1ec1u t\u1ea1o ra. \u0110\u00f3 l\u00e0 m\u1ed9t lo\u1ea1i m\u00e1y ph\u00e1t c\u00f3 \u0111i\u1ec7n \u00e1p kh\u00f4ng li\u00ean t\u1ee5c m\u00e0 lu\u00e2n phi\u00ean. Trong tr\u01b0\u1eddng h\u1ee3p n\u00e0y, ch\u00fang ta c\u00f3 th\u1ec3 hi\u1ec3u l\u00e0 d\u1ea5u c\u1ee7a n\u00f3 \u0111\u00e3 \u0111\u01b0\u1ee3c thay \u0111\u1ed5i m\u1ed9t c\u00e1ch tu\u1ea7n ho\u00e0n t\u1eeb (+) sang (-) v\u00e0 ng\u01b0\u1ee3c l\u1ea1i theo th\u1eddi gian. Ch\u00ednh v\u00ec c\u01a1 n\u0103ng bi\u1ebfn \u0111\u1ed5i \u0111\u1ec1u h\u01a1n \u1edf ch\u1ebf \u0111\u1ed9 th\u1ea5p tr\u00ean m\u00e1y ph\u00e1t \u0111i\u1ec7n xoay chi\u1ec1u \u0111\u00e3 thay th\u1ebf dinamo trong \u0111\u1ed9ng c\u01a1 \u00f4 t\u00f4.<\/span><\/p>\n

T\u01b0\u01a1ng t\u1ef1 nh\u01b0 v\u1eady \u0111\u1ed1i v\u1edbi c\u00e1c \u0111\u1ea7u l\u1ea5y \u0111i\u1ec7n \u1edf trong nh\u00e0 hay v\u0103n ph\u00f2ng, s\u1ebd t\u1ed3n t\u1ea1i m\u1ed9t \u0111i\u1ec7n \u00e1p xoay chi\u1ec1u thay \u0111\u1ed5i d\u1ea5u. S\u1ef1 bi\u1ebfn \u0111\u1ed5i \u0111i\u1ec7n \u00e1p xoay chi\u1ec1u kh\u00f4ng ti\u00eau hao ho\u1eb7c g\u1ea7n nh\u01b0 v\u1eady c\u00f3 th\u1ec3 th\u1ef1c hi\u1ec7n \u0111\u01b0\u1ee3c nh\u1edd m\u1ed9t bi\u1ebfn th\u1ebf, l\u00e0 \u0111i\u1ec1u kh\u00f4ng l\u00e0m \u0111\u01b0\u1ee3c v\u1edbi m\u1ed9t \u0111i\u1ec7n \u00e1p m\u1ed9t chi\u1ec1u.<\/span><\/p>\n

D\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u 1 pha<\/span><\/h2>\n

D\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u 1 pha<\/span><\/i> l\u00e0 d\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u trong m\u1ea1ch \u0111i\u1ec7n xoay chi\u1ec1u c\u00f3 hai d\u00e2y n\u1ed1i v\u1edbi ngu\u1ed3n \u0111i\u1ec7n. H\u01b0\u1edbng c\u1ee7a c\u01b0\u1eddng \u0111\u1ed9 d\u00f2ng \u0111i\u1ec7n trong m\u1ea1ch AC thay \u0111\u1ed5i nhi\u1ec1u l\u1ea7n m\u1ed7i gi\u00e2y t\u00f9y theo t\u1ea7n s\u1ed1 c\u1ee7a ngu\u1ed3n \u0111i\u1ec7n trong m\u1ea1ch. \u0110i\u1ec7n 220V cung c\u1ea5p cho m\u1ed7i h\u1ed9 gia \u0111\u00ecnh s\u1eed d\u1ee5ng l\u00e0 \u0111i\u1ec7n xoay chi\u1ec1u 1 pha v\u00e0 c\u00f3 2 d\u00e2y: d\u00e2y pha v\u00e0 d\u00e2y trung t\u00ednh (d\u00e2y n\u00f3ng v\u00e0 d\u00e2y ngu\u1ed9i).<\/span><\/p>\n

\u00dd ngh\u0129a c\u1ee7a d\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u m\u1ed9t pha<\/strong><\/p>\n

D\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u 1 pha xu\u1ea5t hi\u1ec7n v\u00e0 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng ph\u1ed5 bi\u1ebfn trong sinh ho\u1ea1t h\u1ed9 gia \u0111\u00ecnh. Vi\u1ec7c s\u1eed d\u1ee5ng d\u00f2ng 1 pha ph\u00f9 h\u1ee3p v\u1edbi c\u00e1c thi\u1ebft b\u1ecb c\u00f3 c\u00f4ng su\u1ea5t nh\u1ecf, \u00edt hao ph\u00ed qu\u00e1 nhi\u1ec1u \u0111i\u1ec7n n\u0103ng.<\/span><\/p>\n

Th\u1ebf n\u00e0o l\u00e0 d\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u 3 pha?<\/span><\/h2>\n

D\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u 3 pha <\/span><\/i>l\u00e0 d\u00f2ng \u0111i\u1ec7n trong m\u1ea1ch \u0111i\u1ec7n xoay chi\u1ec1u m\u00e0 v\u1ec1 c\u01a1 b\u1ea3n t\u01b0\u01a1ng t\u1ef1 nh\u01b0 3 \u0111\u01b0\u1eddng \u0111i\u1ec7n 1 pha ch\u1ea1y song song, c\u00f3 chung 1 d\u00e2y trung t\u00ednh. V\u00ec v\u1eady h\u1ec7 th\u1ed1ng \u0111i\u1ec7n c\u1ee7a ch\u00fang ta th\u01b0\u1eddng c\u00f3 4 d\u00e2y, 3 d\u00e2y n\u00f3ng v\u00e0 1 d\u00e2y l\u1ea1nh (Trung t\u00ednh \u2013 0V).<\/span><\/p>\n

\"D\u00f2ng
D\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u 3 pha<\/figcaption><\/figure>\n

\u00dd ngh\u0129a c\u1ee7a d\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u 3 pha<\/strong><\/p>\n

\u0110i\u1ec7n 3 pha \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng cho vi\u1ec7c truy\u1ec1n t\u1ea3i, s\u1ea3n xu\u1ea5t c\u00f4ng nghi\u1ec7p s\u1eed d\u1ee5ng thi\u1ebft b\u1ecb \u0111i\u1ec7n c\u00f3 c\u00f4ng su\u1ea5t l\u1edbn \u0111\u1ec3 gi\u1ea3i quy\u1ebft v\u1ea5n \u0111\u1ec1 hao t\u1ed5n \u0111i\u1ec7n n\u0103ng. H\u1ec7 th\u1ed1ng \u0111i\u1ec7n 3 pha g\u1ed3m 2 d\u00e2y n\u00f3ng, 1 d\u00e2y l\u1ea1nh, \u0111i\u1ec7n \u00e1p chu\u1ea9n \u0111\u1ea7u ra l\u00e0 380V.<\/span><\/p>\n

S\u1ef1 kh\u00e1c nhau gi\u1eefa d\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u v\u00e0 d\u00f2ng \u0111i\u1ec7n 1 chi\u1ec1u<\/span><\/h2>\n\n\n\n\n\n\n\n
Y\u1ebfu t\u1ed1<\/strong><\/td>\nD\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u<\/strong><\/td>\nD\u00f2ng \u0111i\u1ec7n m\u1ed9t chi\u1ec1u<\/strong><\/td>\n<\/tr>\n
Chi\u1ec1u d\u00f2ng \u0111i\u1ec7n<\/strong><\/td>\n\u0110\u1ed5i chi\u1ec1u \u1edf m\u1ed7i n\u1eeda chu k\u1ef3<\/td>\nC\u00f3 chi\u1ec1u x\u00e1c \u0111\u1ecbnh v\u00e0 ch\u1ea3y t\u1eeb c\u1ef1 \u00e2m v\u1ec1 c\u1ef1c d\u01b0\u01a1ng<\/td>\n<\/tr>\n
\u0110\u1ed9 l\u1edbn d\u00f2ng \u0111i\u1ec7n<\/strong><\/td>\nC\u01b0\u1eddng \u0111\u1ed9 bi\u1ebfn thi\u00ean \u0111i\u1ec1u h\u00f2a theo th\u1eddi gian<\/span><\/td>\nG\u1ea7n nh\u01b0 l\u00e0 h\u1eb1ng s\u1ed1<\/span><\/td>\n<\/tr>\n
T\u1eeb tr\u01b0\u1eddng<\/strong><\/td>\nT\u1eeb tr\u01b0\u1eddng bi\u1ebfn thi\u00ean theo th\u1eddi gian<\/td>\nM\u1ed9t h\u1eb1ng s\u1ed1 kh\u00f4ng \u0111\u1ed5i<\/td>\n<\/tr>\n
T\u1ea7n s\u1ed1<\/strong><\/td>\nf=50 Hz, 60 Hz t\u00f9y theo m\u1ed7i Qu\u1ed1c gia. Hi\u1ec7n t\u1ea1i Vi\u1ec7t Nam \u0111ang d\u00f9ng t\u1ea7n s\u1ed1 50 Hz.<\/span><\/td>\nf=0<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

L\u00e0m th\u1ebf n\u00e0o \u0111\u1ec3 chuy\u1ec3n \u0111\u1ed5i t\u1eeb AC sang DC?<\/h2>\n

Khi ch\u00fang ta c\u1eafm s\u1ea1c cho laptop ho\u1eb7c \u0111i\u1ec7n tho\u1ea1i, b\u1ed9 s\u1ea1c s\u1ebd th\u1ef1c hi\u1ec7n m\u1ed9t nhi\u1ec7m v\u1ee5 quan tr\u1ecdng: Chuy\u1ec3n \u0111\u1ed5i d\u00f2ng \u0111i\u1ec7n xoay chi\u1ec1u t\u1eeb \u1ed5 c\u1eafm th\u00e0nh d\u00f2ng \u0111i\u1ec7n m\u1ed9t chi\u1ec1u \u1ed5n \u0111\u1ecbnh \u0111\u1ec3 cung c\u1ea5p cho thi\u1ebft b\u1ecb. Qu\u00e1 tr\u00ecnh n\u00e0y bao g\u1ed3m hai b\u01b0\u1edbc ch\u00ednh:<\/p>\n