5. Half Wave SCR Rectifier/ Resistive Load
R-Load
1
𝑉𝑃 = 𝑉𝑅𝑀𝑆 𝑥 22
1
= 100 𝑥 22
= 141.42136𝑉
𝑇𝑜𝑡𝑎𝑙 𝑡𝑖𝑚𝑒:
𝑃𝑒𝑟𝑖𝑜𝑑 = 1/𝑓
= 1/50
= 0.02 sec
𝐹𝑜𝑟 2 𝑐𝑦𝑐𝑙𝑒𝑠, 𝑡𝑜𝑡𝑎𝑙 𝑡𝑖𝑚𝑒 = 0.04 𝑠𝑒𝑐
Topology circuit:
Vac
Vac rms value
RMS value
Time from: 1.000000 e-005
Time to: 4.0000000 e-002
Vac: 1.0000000 e+002
Calculated Vac: 100V rms
Vdc
Vdc average value
Average value
Time from: 1.000000e-005
Time to: 4.0000000 e-002
Vdc: 4.5015545 e+001
Calculated Vdc average: 45.02V
Idc
Iac rms value
RMS value
Time from: 1.000000e-005
Time to: 4.0000000 e-002
Iac: 1.4142133 e+000
Calculated Iac: 1.41A
SCR:
The SCR a silicon controlled rectifier with an assumed voltage drop of 0.7V.
The simulation results are in accordance with the experimental results.
The differences in the theoretically calculated values by simulation and the measured
experimental values are due to:
The SCR voltage considered in this simulation is not an accurate value.
The voltage set by the variac is not exactly 100vrms.
The resistive load is not actually set to 50 ohms.
The input AC source is not an exact sine wave.
The probes are not calibrated properly.
RL – LOAD
Circuit topology
Vac
Vdc
Idc
Vdc average value
Average value
Time from: 1.000000e-005
Time to: 4.0000000 e-002
Vdc: 3.5921669 e+001
Calculated Vdc average: 35.92V
Iac average value
Average value
Time from: 1.000000e-005
Time to: 4.0000000 e-002
Iac: 7.1952787 e-001
Calculated Iac average: 719.53 mA
Rms
Iac rms value
RMS value
Time from: 1.000000e-005
Time to: 4.0000000 e-002
Iac: 1.0419265 e+000
Calculated Iac: 1.04A
Free Wheel Diode with LR – LOAD
Free wheel diode provide a path for the discharge current.
Circuit topology
Vac
Vdc
Iac
Vdc average value
Average value
Time from: 1.000000e-005
Time to: 4.0000000 e-002
Vdc: 4.5015770 e+001
Calculated Vdc average: 45.02V
Iac rms value
RMS value
Time from: 1.000000e-005
Time to: 4.0000000 e-002
Iac: 9.9103975 e-001
Calculated Iac: 0.991 A
Average current value
Time from: 1.000000e-005
Time to: 4.0000000 e-002
Iac: 6.1366825 e-001
Calculated Iac: 613.67 mA
d) Simple R load with output filter capacitor
Filters are circuits that remove ripples from rectified circuits
Filter capacitor allows ac and blocks dc.
1
𝑉𝑃 = 𝑉𝑅𝑀𝑆 𝑥 22
1
= 50 𝑥 22
= 70. 71068 𝑉
Circuit topology
Vac
Vdc
Iac
Vdc rms value
RMS value
Time from: 1.000000e-005
Time to: 4.0000000 e-002
Vdc: 6.4003291 e+001
Calculated Vdc average: 64.00V
Iac rms value
RMS value
Time from: 1.000000e-005
Time to: 4.0000000 e-002
Iac: 1.2905524e+001
Calculated Iac: 12.91 A
FULLWAVE
a) R – Load
Topology circuit
Vac
Vdc
I
Vdc rms value
RMS value
Time from: 1.000000e-005
Time to: 4.0000000 e-002
Vdc: 9.9999959 e+001
Calculated Vdc average: 100.00V
Iac rms value
RMS value
Time from: 1.000000e-005
Time to: 4.0000000 e-002
Iac: 1.9999992 e+000
Calculated Iac: 2.00 A
b) LR – Load
Circuit Topology
Vac
Vdc
I
Vdc rms value
RMS value
Time from: 1.000000e-005
Time to: 3.9950000 e-002
Vdc: 1.0006252 e+002
Calculated Vdc average: 10.00V
Iac rms value
RMS value
Time from: 1.000000e-005
Time to: 3.9950000 e-002
Iac: 1.7166231 e+000
Calculated Iac: 1.72 A
c) Simple R- Load with output filter capacitor
Circuit Topology
Vac
Vdc
I
Vdc rms value
RMS value
Time from: 1.000000e-005
Time to: 4.0000000 e-002
Vdc: 6.766467 e+001
Calculated Vdc average: 67.66V
Iac rms value
RMS value
Time from: 1.000000e-005
Time to: 4.0000000 e-002
Iac: 1.2391495 e+001
Calculated Iac: 12.39 A