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My inverter is not working and, please help I may not graduate because of this

TarfaEE

Apr 1, 2021
3
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Apr 1, 2021
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Hello all,

I'm building a three phase motor controller, I've designed the circuit on a PCB and I'm trying to test the inverter and it is not working.
I'm using an IR2104 to drive the mosfets, the LO is fine but the HO is a noisy dc signal for some reason. I'm driving it with a 64khz PWM signals from an Arduino due.
I made sure the low mosfets are on first (to charge the capacitor).
attached is the schematic and the PCB layout. Originally I used am IRS2186 but I changed it to IR2104 with the appropriate connections made.
 

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Alec_t

Jul 7, 2015
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I don't see a connection between the VS input of the IC and the top MOSFET's source. Without that the boost won't work.
 

TarfaEE

Apr 1, 2021
3
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Apr 1, 2021
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I don't see a connection between the VS input of the IC and the top MOSFET's source. Without that the boost won't work.
Vs is connected to the phases of the mosfet. It’s the mid point between the upper and lower mosfets
 

Alec_t

Jul 7, 2015
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That's where it should be connected, but I don't see it in your schematic or board layout.
 

TarfaEE

Apr 1, 2021
3
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Apr 1, 2021
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That's where it should be connected, but I don't see it in your schematic or board layout.
It is connected the whole red via surrounding the top mosfet is conducting, I just checked using continuity test on a multimeter
 
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