Переходные процессы в электрических цепях (E=150 В, L=0,09 Гн, R1=300 Ом, R2=300 Ом, R3=600 Ом, C=5 мкФ, ключ размыкается), страница 4

Величина

t<0

t=0

t®

По законам Кирхгофа

По уравнениям

По законам Кирхгофа

По уравнениям

i1 (t) [A]

0.25

0.125

i2 (t) [A]

0

0.167

0

0

i3(t) [A]

0.083

0.125

uR1(t) [B]

75

37.5

uR2(t) [B]

25

37.5

UR3(t) [В]

0

50

75

UC [B]

75

112.5

UL [B]

0

0

0

0


11. Операторный метод

I3(p)

 

 

 

I2(p)

 

I1(p)

 

 

 

 

 

 

 

Составим систему уравнений в операторной форме:

                                                                                                                                                     (69)

Подставим начальные условия:

и преобразуем систему (69) относительно :

                                                                                                                                                     (70)

                                                                                                                                                     (71)

                                                                                                                                                     (71)

                                                                                                                                                     (72)

                                                                                                                                                     (73)

                                                                                                                                                     (74)

                                                                                                                                                     (75)

Перейти от изображения к оригиналу с помощью теоремы разложения (76):

                                                                                                                                                     (76)

Найдём производную полинома F2:

                                                                                                                                                     (77)

Подставляем корни:

                                                                                                                                                     (78)

                                                                                                                                                     (79)

                                                                                                                                                     (80)

Т. о.                                                                                                                                                      (81)

Формула (81), полученная операторным методом, совпадает с формулой (61), полученной с помощью классического метода.


12. Расчёт методом переменных состояния