H Bridge Mosfet Using Transformer instead of Motor Help!!!

[MrDestruction]

h bridge mosfet

hey guys, i am working on an inverter circuit, i will post the circuit soon once i get this fixed. I am trying to run the transformer from my H Bridge Mosfet circuit. But instead of the motor i am going to attach the transformer. The H bridge is working great (square wave for now).

So basically can i hook up my transformer to the H bridge output.

H bridge Output = 12Vac square wave

I want to ramp the voltage to 120 VAC using transformer. Any help would be greatly appreciated.

I am not building, i am simulating. (Multisim)

 

[LordAli]

h bridge mosfet circuit

I cant understand what you wanna help with? If you want to make 120V from 12V, just use 110) ratio step up transformer. If you wanna know inductance, search for some equations in google. There's plenty of it.

You will design it using usual step down topology (even if you use step-up transformer).

 

[MrDestruction]

using transformer in place of motor

well that's what i thought, but when i hooked up my transformer CT it does not work, i have uploaded my schematic.

Please any help why the transformer is giving me errors when i connect to the H bridge.

 

[LordAli]

h bridge mosfets

Because you need to connect transformer to H-bridge diagonal (between Q2 and Q4 drains). No need for centertapped transformer. And disconnect Vdd from transformer CT.

Transistors Q1 and Q4 are switched together, then conductivity is reversed to Q2 and Q4. You need to proper drive and timing including deadtime to prevent connecting Vdd to GND for a short moment.

 

[MrDestruction]

h-bridge mosfet

i have uploaded my graph images after i loaded the transformer. but once i set the transformer in place, i get the oscillation but its not square wave, what do you think is wrong? do you think that its my BJT's slow switching and no deadtime?

let me know what you think.

 

[LordAli]

h-bridge mosfet circuit

I think you need another high-side driver. Not exactly Vgs = GND is always solution. Maybe if Vgs of high-side transistor Vgs = 0V is better solution. This means you need to switch MOS between G and S instead of G and GND.

 

[FvM]

using transformer in place of moter

The waveforms indicate, that your simulated design is miles away from an operational real design. Either the transformer inductance is much too low or the MOSFET switch dimensioning is completely unsuitable. As already mentioned, the drivers most likely need improvement, but they are not causing the said problems, I think.