Guru
Joined: 21/06/2018
Location: AustraliaPosts: 1309
| Posted: 04:21am 14 Jul 2019 |
Time for an update on my inverter. Had some surgery to my finger a few weeks ago and haven't achieved a lot one handed since....
Have fitted all the Mosfets, insulating pads and ferrite beads. I wasn't sure when I designed the PCB whether I would have a fully isolated heatsink or connect it to Battery Neg. I decided to ground it to Bat neg & used the lower FETs mounting screws to achieve this via the PCB ground-plane. The upper row of FETs required an insulating shoulder washer so the Batt+ ground-plane was not shorted to ground also.
The Enphase solar battery I recently acquired was only a 24V LiFePO4 not 48V so my testing will soon move to a 24V inverter configuration. By having a fully isolated gate power supply & opto drive I can use any input voltage to the Power board from 0 - 60V, I only need to change the transformer and choke. Obviously voltages below 12V are very useless except for initial power up & anti-smoke testing.
Running from a 30V 3A bench supply it all actually appears to works very well so far with an 18V primary transformer.
Today I might have bagged a good bargain on Ebay, it is a 10KW 3Phase to 48V @ 210A rectifier unit. They claim brand new never used for $75!. All in a 3u High ~ 5" rack module @ 32kG lol. I used the buy it now button - just need to figure out how to get it to SA as its in Sydney & he wanted collect, no postage. For interest here is the brochure :2019-07-14_141706_PFM10kW.pdf
That should help with testing my inverter and later I can use it as a fast charger when I eventually get batteries.
Update pictures below:
If at first you dont succeed, I suggest you avoid sky diving....
Cheers Mike