Has anyone heard anything about a central electronic air purifier that is part of a heat pump unit?

Question

Or how well they work?

Answer 1

Yes, they use static electricity to capture micronic dust that makes it past your filters.   You need to have them installed by your HVAC technician, and wired by an electrician.

You need to clean them periodically.  They need to be off for a while, then you remove the plates, rinse them off with a hose, and let dry before re-installing.

I can't speak for how well they work.  I've only wired a few.