What's the difference between a resistor and an electronic load in CR mode?

[Qingxuan]

Hello,
I am used a Chroma DC electronic load (63206A-600-420 ) in constant resistance (CR) mode as my PFC's load and the inductor current would always lose control after several seconds of operation.
When I change the load from electronic dc load to real resistor, the converter would always work. This really confused me.
In my simulation, I used a R as converter's load and the system would always work very well.
Do there exists any large difference between CR mode electronic load and real resistors? Thanks!

 

[Easy peasy]

CR on an electronic load has a time constant to the loop reponse - so the load and your circuit can interact

a real resistor has an almost zero time constant ( or delay between volts going up and current going up ) and hence will be more stable ...

 

[dick_freebird]

I have had similar problems with E-loads at
test and won't use them. If I want a variable
load I build my own out of switched-resistor
(MOSFET + drain resistor) networks.

 

[opampsmoker]

E-loads arent that great.....not for everything..

https://www.edaboard.com/threads/why-does-electronic-load-have-capacitance.348533/

You cant really do a transient response test with an eload...it effectively adds capacitance to the smps output...and C is an smps feedback loop parameter.