maybe the layout is the problem.
There are two fundamental "ground plane" to make
The first is the signal/output ground (GND): you've to use a plane to connect comparator, input signal, and level shifter. Al least, the output capacitor.
Then, the second, there's is a "power ground" that is "ground" for the power stage but not a real ground (i mean, 0 volt): it's -HV. You've to connect the IR2010, the phase shifter pull-down, the output mosfet
Final: hard decoupling. +HV to -HV, +HV to GND, -HV to GND with electrolitic+film, and the op-amp voltages
Can you post some waveforms?
I need:
- pwm before LC filter (if you can, at 50% duty, so no signal)
- output signal after the LC.
If your noise goes up when you put more IR modules in the same chassis, i think in a layout problem so your pcb is a little antenna.