Hi, I am trying to drive a half-bridge.

circuit-1 is the main circuit diagram relevant to this post. circuit-2 contains the remaining circuit. The CMOS-H pair is driven by Q, and the CMOS-L pair is driven by Q-INV. CMOS-H drives IPP-H, while CMOS-L drives IPP-L. Q, Q-INV, and the rest of the circuit in circuit-2 are correct and as expected.

The MOSFETs in the half-bridge do not turn on/off completely. Vo-MAINS, the output of the half-bridge, hits only 160V, much less than the 800V mains. Vgs for both IPP MOSFETs hits 0/12V as per the waveforms, so the MOSFETs should turn on/off completely.

What could be happening here?

 

The gate drive to an FET must be applied between the gate and the source points, and the voltage must be adequate, and the drive circuit needs to both supply charge and remove it to achieve both cutoff and saturation. Actually achieving that is not always simple.

 

As the Vgs meters indicate, i am able to drive sufficient voltage and current into the gates of all MOSFETs

 

since the rest of the circuit is not shown, there is no way to offer an evaluation of how it would function.
I am not a mind-reader, nor do I have the ability to see beyond the edges of my screen. Thus I am unable to evaluate the circuit completely.