Circuit Gives DC Current instead of Sine signal (LTspice XVII)
All your PMOS are upside down hence the parasitic diode in each (show by my red lines) is conducting a massive and unfeasible current from the power source: -

Given that the four PMOS are identical, the outputs will from a 2:1 potential divider and convert your input supply of 200 volts into an output of 100 volts.
I think you need to relook at what the original idea is behind your simulation because 4 MOSFETs wired like this can never properly work.

Original idea (oops they got that wrong):
Unfortunately, you can't rely on the diagram in the document you cite. It also shows PMOS devices (wrong) and also shows each half bridge gates connected together (also wrong): -

Here's a blow-up of Q1: -

Clearly and unambiguously, this is incorrectly drawn as a P channel MOSFET when it should be either an N channel MOSFET or a P channel device with source and drain reversed.