2- Dinh Iv ve tinh duv nhat
2.5.3 Ma tran tan xa (S)
Ngoai cae be phuong trinh (2-16) va (2-18), mang \iba eon eo the dugc mo ta theo mot each nhin khaẹ Ta biei rang, tai moi mat iham khaọ dien ap \a dong dien la t6 hgp eiia song toi va song phan xa:
V ^V ^y-, (2.40a)
n n n '
/ =r-r (2.4()b)
n 'I »
Sdng phan xa cd the dugc bieu thi qua he 56 phan xạ Thuc rạ khai niem "song loi"" va "sdng phan xa" co lh6 dugc hieu theo mgl y nghTa rong hon:
- Sdng tdi la sdng di lir ngoai N ao mang (sdng ve) - Sdng phan xa la song di tir trong mang ra (sdng di)
Vi vaỵ "sdng phan xa" tai moi cua cd the do chinh song tdi o cua do tao rạ nhung cung cd tha do sdng tdi d cae cira khac. Gia sir song tdi o mat tham khao cua nhanli
1 la thi ^^song phan xa*^ do no gay ra a cae mat tham khao ciia cae nhanh se ti le vai theo cae he so ti le khac nhau:
V~ =S V*
2 ''iV \
(2.41)
Tuang tu, vai song tai a mat tham khao ciia nhanh p, ta co song phan xa a eac nhanh:
2 Ip p
(2.42)
Neu a tat ca cae nhanh ciia mang deu co song tai thi song phan xa o cae eua se nhan dugc theo nguyen ly xep chong. Ta eo he phuong trinh sau:
v;-sx^^n^2^ s',^'';
K=s,J':^s,,r^ s,,v:
Day chinh la he phuang trinh tan \a cua mang \ibạ
Ma tran tan xa [S] mo ta quan he giua dien ap song toi \a dien ap song phan \a lai cae cong ciia mang:
(2.44 ' ' • , " ' ' • , " 'V / ^ . ~ 'Su • ^ ' : i _ ' " ^ . M S S .s\,.. ...s,. 1 ...s,. ...s.. K r: ^':
hoac vitn dudi dang riit ggn:
\rMS][r].
Cae phan tiJr S,,,^ ciia ma tran [S\ co the dugc xac dinh nhu sau:
s..J^
K (2.46)
5^^ dugc xac djnh bang each cap dien cho cong q voi dien ap "song tai" va do bien
do cua "song phan xa" (song di ra khoi mat tham khao cua cong p), eon "song tai" tai cae cong khac deu bang 0, nghTa la tai cae cong khac vai p deu dugc ph6i hgp tra khang. Sp^ la he so phan xa tir cong p khi tat ca eac cong khae deu dugc phoi hgp tra khang.