Problems with Harmonics - LNK417
Hi,
I design a LED-Driver for Streetlightnig. But we have massiv problems with harmonic currents @ 5,7,9,11 orders.
Effency of the driver is ~ 91,5% (very nice performance). Is it possible that we do a big fail with the filters or "DC" Caps? Powerfactor isnt stabil but with full Load we get an PF of 97%
Please refer to the atteched PDF.
Transformer:
1207µH prim
2x 28T prim (Series), 2x 14T Sec(Parall), 9T Bias
Core: PC44; PQ3230
The same configuration like the RDR-290 Transofrmer
System Parameters:
30W-Outputpower, 230V 50Hz AC Input, 0,88A @32-36V Output
2.
I want use the Transformer and the System for a 50W and 75W Powersupply... only change the LNK-IC. Is That possible?
Thank you for help.
*** 09.01.15
I add a picture from my mesured values ... Order 9 and 11 are the biggest problem.
Comments
Thank you for fast answer.
Yes I think I have some problems with our transformer.
PIXI calculate me Primary Inductance: 2900µH ... and my transformer have ~ 1205µH
Can i edit the Prim. Windings manual? I cant setup the "real" transformer in my spreadsheet.
Thats really hard ... we buyed 500pcs from this transformer and rebuild the RDR-290 with 35W Power! Is that desing with this transformer rescueable?
Thank you :(
| Attachment | Size |
|---|---|
| LinkSwitch-PH Design1.pdf (71.35 KB) | 71.35 KB |
Thank you for fast answer.
Yes I think I have some problems with our transformer.
PIXI calculate me Primary Inductance: 2900µH ... and my transformer have ~ 1205µH
Can i edit the Prim. Windings manual? I cant setup the "real" transformer in my spreadsheet.
Thats really hard ... we buyed 500pcs from this transformer and rebuild the RDR-290 with 35W Power! Is that desing with this transformer rescueable?
Thank you :(
| Attachment | Size |
|---|---|
| LinkSwitch-PH Design1.pdf (71.35 KB) | 71.35 KB |
VOR and NS are user inputs. If you fixed VOR then change NS (or vice versa) NP will change accordingly.
The Link-Switch-PH spreadsheet has a harmonic calculation at the bottom of the spreadsheet. Use this to obtain your desired objective. To reduce harmonic content, you can play by reducing KP and/or increasing VOR on your transformer design.
Using the same transformer for 3 different power might be possible but of course have tradeoffs as you cannot get the best performance. You can also use the spreadsheet to do this.