Hello Guys,

I have implemented a simple half-wave SCR rectifier with RL load on PSpice. The supply has amplitude 50V and period 20ms. The firing angle of the SCR is 90°. I simulated the circuit and generated the transient plot for load voltage. The waveform obtained was almost as expected in theory except for one feature: At the extinction angle, there are some small oscillations before the load voltage gets back to zero.

See the waveform below for only one cycle (i.e. 20 ms)


What is the explanation for this?
Thanks

 

Zero loss capacitors (no esr), no wire inductance, no wire resistance...

Real circuits show this tendency but to a much lesser extent than simulation using ideal components...

 

Zero loss capacitors (no esr), no wire inductance, no wire resistance...

Real circuits show this tendency but to a much lesser extent than simulation using ideal components...

Can you please elaborate?

 

Hello,

Here is an example of the comparison of a model of the capacitor as in the simulator and a real world capacitor:

This image is from this PDF : Decouple capacitors
wich can be found in this thread:
http://forum.allaboutcircuits.com/threads/decoupling-or-bypass-capacitors-why.45583/

Bertus

 

Hello,

Here is an example of the comparison of a model of the capacitor as in the simulator and a real world capacitor:

This image is from this PDF : Decouple capacitors
wich can be found in this thread:
http://forum.allaboutcircuits.com/threads/decoupling-or-bypass-capacitors-why.45583/

Bertus

OK, but why do the oscillations occur only at the discontinuities? And why only at the extinction angle and not the firing angle (because there is a discontinuity there also)?