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poida

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Joined: 02/02/2017
Location: Australia
Posts: 1446

Posted: 05:49am 25 Jan 2026

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63 parts.

4 fets
2 bulk caps 63V 3300uF

5 v1 highside drive
5 v2 highside
4 v1 lowside
4 v2 lowside

5 Vdd signal contitioning

2 v1 pulse maker IR2184
2 v1 pulse maker

18 Vfb signal conditioning

3 Heat sink 10 NTC signal conditioning

3 underneath Nano
1 nano

3 15V -> 5V linear reg
some 0.1" pin headers
2 heat sink fan FET and gate pull down resistor

I use HY5608 FETs and when fed 50V, only need to switch about 40A so I
think these FETs will be just fine.

idle current was 0.2A DC at 54V input for 239V AC output.
The toroid makes a huge difference in idle power and I am running
this one well below any hint of saturation.

I'm really quite happy with it.
Obviously I could build it with thicker V1 and V2 output cables but I
just could not be arsed, really.

It runs the picoverter code, which features low DC voltage shutdown
with auto restart, fan control for the heat sink and heat sink over temp shutdown.

The semiconductors are:
HY5608 80V 360A 1.5 mOhm Rds(on)
IR2186 gate drive IC
FOD3182 gate drive IC
LM358 dual opamp
LM7805 linear reg
any old logic level FET to drive the fan

it worked first time I applied power!

Edited 2026-01-25 15:50 by poida

wronger than a phone book full of wrong phone numbers

poida

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Joined: 02/02/2017
Location: Australia
Posts: 1446

Posted: 02:56am 27 Jan 2026

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it works well, only tested it to 1330W AC so far.

for the 1330W AC output (0.99 power factor), input is 54.7V at 29.1A
1590W in, 1330W out, it's 83.5 % efficient

Rather thin wire is used in the primary circuit, it's 4mm2 I think.
this wire is the primary winding and I need 3 meters of it.
I probably could pick up a few more % if thick stuff was used.
the DC resistance of the primary is 48 mOhm.
(I determined that by putting 5.8A DC through it and reading 281mV across it)

here is a thermal image of it running under this load.

the hottest part is where the low and high side FETs are soldered
sort of where "VS1" and "VS2" are located in the above image.

wronger than a phone book full of wrong phone numbers

analog8484
Senior Member

Joined: 11/11/2021
Location: United States
Posts: 184

Posted: 06:57pm 27 Jan 2026

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Nice little board. Is it 1 oz copper?

Also, curious if you have observed false MOSFET gate turn-on transients like the ones in your past reports on larger inverters.

poida

Guru

Joined: 02/02/2017
Location: Australia
Posts: 1446

Posted: 12:23am 30 Jan 2026

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it is 1oz copper, if it shows promise I will make a v.2 with 2 oz copper, error fixes, unused footprints removed and space for 3rd main cap.

I have 3 similar inverters to compare.
this one, the first version of it that uses TIP41/42 transistors in the totem pole
type gate drive and Wiseguy's inverter with it's professional design.

All 3 require about 1330 W input to drive the same load. Maybe Wiseguy's inverter
used 1300 W but the load varies over time so it's hard to get it accurate.

The next thing to examine is gate drive signal shapes and look for shoot through
at idle and under load.

I want also to play with more or less capacitor powering the drive side
of the FOD3182 chips. At the moment it is only 1uf ceramic
with ESR of about 3 Ohms.
In the past I have used 10uf electro (ESR of 10 Ohms) with a 0.1uF ceramic parallel.

I varied gate drive voltage while running under load and changing from 12 to 15V
made no difference to input power.

Finally, I might need to put "some" resistance in the gate drive, at the moment
the FET gate is direct connected to FOD3182 output and I suspect there is
MHz oscillation. No doubt that is causing some shoot through.

wronger than a phone book full of wrong phone numbers

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