HiperPFS design equations
Hi!
Im new to this forum, so I salute you all!
Im finding it hard to replicate the results in the spreadsheet of PI Expert regarding a 550W PFC using the PFS727EG.
Is there any app note of yours or material to read where I can find the design equations you are using in the spreadsheet? Speccially those regarding the Inductor Design (Inductance & number of turns).
In the other steps I'm finding results very similar to those on the spreadsheet, but I can't seem to get the same number of turns for the coil as you guys do on the software.
Thanks and I pardon my English, for it is not my mother language.
Esteban.
Comments
This thread is six months old and appears abandoned, so I'll just use it instead of creating a new duplicate.
The question that Esteban initially asks is, are the equations and assumptions made in the PIXls spreadsheets available in any other form? In my case I want to investigate the effects of either an odd sized PQ core (Magnetics PQ3214), or a more exotic material (MPP), in order to meet a size constraint, but the result is the same - I end up trying to reverse-engineer the PIXls sheet in order to get enough information to do my own what-if analyses.
I don't have the time nor money to iterate designs several times through build-and-check as the application notes suggest, and I'm certain other customers don't as well. Is there a better way to get at the raw calculation data?
Unfortunately the equations are not available anywhere else.
What problem are you trying to solve?
The problem I'm trying to solve is whether the PIxls results I'm getting are actually accurate. Certain combinations of inputs produce results which seem unreasonable, and without some insight into how the calculation is done, I don't want to blindly trust it.
Most of the calculations being done are simple physics and material properties lookup tables, but there are a few parameters key to the device itself that I can't work out. For instance, how are the peak and average switching frequency calculated? We are given only graphs in the datasheet, which cover only selected cases. Calculating inductor values without having an accurate estimate of switching frequency is difficult.
Peak and average switching frequencies are calculated via a simulation over a line half-cycle.
What is it about the inductor value you are trying to calculate?
As I said in my original response, I'm looking at alternate core geometries and alloys to those allowable through the PIXls calculation environment. Calculating core losses requires the switching frequency.
I find it hard to believe that PIxls is doing a full simulation in the background every time a parameter is changed (or were the simulations pre-calculated and it uses a gigantic lookup table?), and equally hard to believe that the relatively simple-looking ramp generator in the HiperPFS-2 can't be distilled to a set of equations. I'm surprised that this isn't a more common complaint.
It doesn't take long to calculate a few hundred switching cycles. It does a simplified time domain simulation.
There are equations that describe the switching frequency. They're used in the simulation.
But those equations are not available outside the simulation?
We don't have a closed form equation for the frequency plot vs. line angle. We solve it numerically.
What core material are you using?