P
P E Schoen
I want to make a DC-DC converter for 48 VDC to about 300 VDC at a continuous
power of about 800W to drive a 1 to 2 HP three phase induction motor. I have
some E55 cores and coilformers which should do the job, and also some
E47/20/15 which might work OK. The E55 is an Epcos type N27 and the E47 is
probably the same.
http://www.mouser.com/ds/2/136/e_47_20_16-75097.pdf
http://www.mouser.com/ds/2/136/e_55_28_21-73714.pdf
I found a website that shows a simple procedure to determine the turns
required for a transformer in a half-bridge topology using three capacitors.
I plan to use the same circuit but not use the additional series capacitor
and instead use two 20 uF 100 VAC PP capacitors in series across the DC bus
and the center to one end of the primary.
http://tahmidmc.blogspot.com/2013/02/ferrite-transformer-turns-calculation_22.html
The LTSpice for the basic circuit is on my server:
http://enginuitysystems.com/pix/48V-320V_DCDC_HalfBridge_2Cap.asc
I made a spreadsheet to automate the selection process and for the E55 core
and 50 kHz it came up with 23 turns of #8 AWG for the primary at 33 amps and
144 turns of #16 for the secondary at 5.3 amps. It appears to have 8 watts
of ferrite losses and about 6 watts primary and secondary copper losses for
total efficiency of about 97%.
Here is the (OpenOffice) spreadsheet. Please have a look and see if it is at
least close to being accurate:
http://enginuitysystems.com/files/Ferrite_Transformer.ods
Another question I have is if would be helpful to use heat shrink tape to
compress the ferrite halves:
http://www.mcmaster.com/#heat-shrink-tape/=pjzuzt
And, finally, I think it would be good to use Litz wire for this. I found
some that seems to be a good deal:
http://www.ebay.com/itm/370951676185
Thanks,
Paul
power of about 800W to drive a 1 to 2 HP three phase induction motor. I have
some E55 cores and coilformers which should do the job, and also some
E47/20/15 which might work OK. The E55 is an Epcos type N27 and the E47 is
probably the same.
http://www.mouser.com/ds/2/136/e_47_20_16-75097.pdf
http://www.mouser.com/ds/2/136/e_55_28_21-73714.pdf
I found a website that shows a simple procedure to determine the turns
required for a transformer in a half-bridge topology using three capacitors.
I plan to use the same circuit but not use the additional series capacitor
and instead use two 20 uF 100 VAC PP capacitors in series across the DC bus
and the center to one end of the primary.
http://tahmidmc.blogspot.com/2013/02/ferrite-transformer-turns-calculation_22.html
The LTSpice for the basic circuit is on my server:
http://enginuitysystems.com/pix/48V-320V_DCDC_HalfBridge_2Cap.asc
I made a spreadsheet to automate the selection process and for the E55 core
and 50 kHz it came up with 23 turns of #8 AWG for the primary at 33 amps and
144 turns of #16 for the secondary at 5.3 amps. It appears to have 8 watts
of ferrite losses and about 6 watts primary and secondary copper losses for
total efficiency of about 97%.
Here is the (OpenOffice) spreadsheet. Please have a look and see if it is at
least close to being accurate:
http://enginuitysystems.com/files/Ferrite_Transformer.ods
Another question I have is if would be helpful to use heat shrink tape to
compress the ferrite halves:
http://www.mcmaster.com/#heat-shrink-tape/=pjzuzt
And, finally, I think it would be good to use Litz wire for this. I found
some that seems to be a good deal:
http://www.ebay.com/itm/370951676185
Thanks,
Paul