Contents Chapter 1: Introduction 2: Simple Diode Circuits 3: Simple SCR Circuits 4: Fully Controlled 1 PH 5: Fully Controlled 3 PH 6: Semi - Controlled Rectifier Circuits 7: Switch MOde PowerSupply previous page Section Contents next page

 

Chapter 3
Simple SCR Circuits

Section 2
A Single SCR Circuit with a Free - Wheeling Diode

 

 

PSPICE Simulation

The circuit used for Pspice simulation is shown below.

The Pspice program is presented next.

* Half-wave Rectifier with a free-wheeling diode
* A problem to find the SCR current
VIN 1 0 SIN(0 340V 50Hz)
XT1 1 2 5 2 SCR
VP 5 2 PULSE(0 10 1667U 1N 1N 100U 20M)
L1 2 3 31.8MH
R1 3 0 10
D2 0 2 DNAME
.MODEL DNAME D(IS=10N N=1 BV=1200 IBV=10E-3 VJ=0.6)
* Subcircuit for SCR
.SUBCKT SCR 101 102 103 102
S1 101 105 106 102 SMOD
RG 103 104 50
VX 104 102 DC 0
VY 105 107 DC 0
DT 107 102 DMOD
RT 106 102 1
CT 106 102 10U
F1 102 106 POLY(2) VX VY 0 50 11
.MODEL SMOD VSWITCH(RON=0.0105 ROFF=10E+5 VON=0.5 VOFF=0)
.MODEL DMOD D((IS=2.2E-15 BV=1200 TT=0 CJO=0)
.ENDS SCR
.TRAN 10US 60.0MS 20.0MS 10US
.PROBE
.OPTIONS(ABSTOL=1N RELTOL=.01 VNTOL=1MV)
.END

The waveform of voltage at the cathode of SCR



The waveform of current through the load



The waveform of voltage across the SCR


The waveform of current through the SCR


The waveform of current through the free-wheeling diode


The waveform of voltage across the inductor

 
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