EEL 5245 POWER ELECTRONICS I

Lecture #8: Chapter 3 Diode/SCR Switching Circuits-AC

Objectives

•  Emphasize mode-by-mode analysis •  Simulating Ideal Elements •  Introduce Load Regulation •  Introduce Current Commutation •  Introduce Concepts of Steady State/Transient •  Present Current Freewheeling •  Define Inductor Current Ripple •  Inductor Voltage Average Value is Zero (Steady State) •  Half Wave Inductive Rectifiers w/ and w/out Freewheeling Diode •  Derivation of Full Bridge w/ Cap. Load

–  Introduce Output Voltage Ripple –  MathCAD usage

•  SCR Switching Circuits –  Current Freewheeling

Half Wave Rectifier w/ Inductive Load

Time0s 5ms 10ms 15msV(Vs:+) V(Vload) I(L1)

-100

0

100

Time

8.00ms 9.00ms 10.00ms7.20ms 10.88msV(Vs:+) V(Vload) I(L1) 0

-40

-20

-0

20

Half Wave Rectifier w/ Inductive Load

Time

0s 5ms 10ms 15msI(R1) V(Vload) V(Vs:+)

-100

0

100

Time

8.00ms 10.00ms 12.00ms13.55msI(R1) V(Vload) V(Vs:+) 0

-50

0

-82

26

Half Wave Rectifier w/ Inductive LoadVoavg

Time

0s 5ms 10ms 15msI(R1) V(Vload) V(Vs:+)

-100

0

100

Half Wave Rectifier w/ Inductive Loadand Freewheeling Diode

Time

0s 5ms 10ms 15msI(R1) V(Vload) V(Vs:+)

-100

0

100

Half Wave Rectifier w/ Inductive Loadand Freewheeling Diode

Time

0s 5ms 10ms 15msI(R1) V(Vload) V(Vs:+)

-100

0

100

Half Wave Rectifier w/ Inductive Loadand Freewheeling Diode

Time

130ms 140ms 150ms 160msI(R1) V(Vload) V(Vs:+)

-100

0

100Time

0s 50ms 100ms 150msI(R1) V(Vload) V(Vs:+)

-100

0

100

Half Wave Rectifier w/ Inductive Loadand Freewheeling Diode

Time

140.0ms 150.0ms 160.0ms133.3msavg(V(R1:2,L1:2))

-50V

0V

50VI(R1) V(R1:2,L1:2)

-100

0

100

Half Wave Rectifier w/ Inductive Loadand Freewheeling Diode

Time

130ms 140ms 150ms 160ms 170msI(L1) V(Vs:+)

-100

0

100

Time

140ms 150ms 160ms133ms 167msI(L1) V(Vs:+) -I(Vs)

-100

0

100

Full Wave Rectifier w/ Output Cap

Time

85ms 90ms 95ms 100msV(S1:4) V(ABS1:OUT)

0V

100V150V

avg(V(S1:4))160.0V

162.5V

165.0V

Time

85ms 90ms 95ms 100msV(S1:4) V(ABS1:OUT)

150.0V

160.0V

170.0V

178.5V

Time

85.0ms 90.0ms 95.0ms 99.9msV(ABS1:OUT) V(S1:4)

0V

100V

150V

I(ABS1)-1.0A

0A

1.0A

2.0A

Phase-Controlled Half WaveRectifier w/ Inductive Load

Time

0s 5ms 10ms 15msV(Vload) I(R_Isense) I(L1) V(Vs:+)

-100

0

100