Power inverter circuit in proteus giving DC output

Thread Starter

Umat

Joined Dec 6, 2016
7
Hello,

My DC to AC converter circuit (attached) does not produce AC output. I have connected a pulse generator to one pair of the bridge switches. The other pair is connected from the same pulse source except that the inputs are inverted through a not gate.
PowerInverter.jpg
I intend to replace the pulse generators with microcontroller PWMs after I get the circuit working.

Kind regards.
 

HW-nut

Joined May 12, 2016
97
The circuit needs some help.
1) The supply connection is incorrect, should be top half.
2) Gate driver for high side needs to go above the main supply to turn on.
 

Thread Starter

Umat

Joined Dec 6, 2016
7
Thanks a lot Hut,

I have now connected the positive terminal of the battery to the drain of the top MOSFETs and the negative terminal to ground. I have also connected the bottom (source) of the lower MOSFETs to ground. But I can't figure out how to make my gate driver goes above supply? The gate drive signal is only 12V.

Kind regards.
 

Thread Starter

Umat

Joined Dec 6, 2016
7
I have changed my transistors to N-Channel type MOSFETs, does this seem better? and have also changed the connections as shown below.
powerConverter3.png
 

HW-nut

Joined May 12, 2016
97
You are moving in the right direction. The N-channel MOSFET's will work. The gate drive will not work. But first, learning a H-bridge drive with a 200v supply is dangerous, make sure you know what you are doing. You may want to start with a 12v D.C. Motor and go from there.

As for the circuit, assuming the driver is ok for the low side, the high side will not work. You can either Change the high-side MOSFET's to P-channel or use a bootstrap driver.

I would also be very concerned over the turn-on/ turn-off time. The circuit will die a violent death if the MOSFET's cross conduct.

Look at some of the gate drivers from TI or linear tech to understand the issues.

Good luck. For what it's worth, I designed some dangerous circuits when I was a kid. Good for a 7500v shock.
 
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