How to design voltage loop for three-phase PFC DCM boost Rectifier?

[[email protected]]

Hello. I am trying to design a simple three phase PFC DCM
(discontinuous conduction mode) boost rectifier. I already have
designed the power stage and now want to design the controller for the
output voltage loop. Can anybody tell me what model should I use for
the power stage to design the output voltage compensator? Any other
recommendations? Thank you in advance!

 

[Reg Edwards]

(discontinuous conduction mode) boost rectifier. I already have

designed the power stage and now want to design the controller for the
output voltage loop. Can anybody tell me what model should I use for
the power stage to design the output voltage compensator? Any other
recommendations? Thank you in advance!

Why not ask a real electrical engineer? It would be safer.

 

[[email protected]]

Hello. Thanks for your concern, but I only want to simulate such a
circuit, not build it!

 

[Terry Given]

Hello. I am trying to design a simple three phase PFC DCM
(discontinuous conduction mode) boost rectifier. I already have
designed the power stage and now want to design the controller for the
output voltage loop. Can anybody tell me what model should I use for
the power stage to design the output voltage compensator? Any other
recommendations? Thank you in advance!

Use a PI controller. Messers Zeigler & Nicholls can be used to tune it,
without bothering with the actual plant model. Thats what everyone else
does.

If you have an inner current loop, then calculate the current loop gain
(as seen by the much slower voltage control loop) as

Gc = dIout/dVcontrol

where Vcontrol = output of voltage controller error amp (after whatever
diodes, resistive dividers etc are in the way)

because its DCM you will find Gc varies with Vcontrol. One would
normally design with Gc(max). When you transition into CCM Gc will
become constant.

Then ignore the inductor etc. and "pretend" you have a current source,
gain Gc, driving your DC bus cap (inc. ESR) and load, the small-signal
response of which is trivial to calculate.

Choose your voltage loop bandwidth less than the inevitable output
ripple. In the case of single-phase PFC, 10-20Hz is commonly used, but
of course this can be much higher in a 3-phase system.

Cheers
Terry (a "real" electrical engineer)

 

[Fabio G.]

[email protected] ha scritto:

Hello. Thanks for your concern, but I only want to simulate

Which software are you using to simulate it?
In MatLab 7 you can find an example of the 3-phase rectifier: you could
be inspired by that model to better understand the control loop.

 

[[email protected]]

Hello. thank you for your replies. I plan on using Saber to simulate
the circuit. I will look into Terry's advice. Thanks again to all and
if you have more advice send it this way!