Back in 2006 I was contracted to design a power amplifier prototype for the civil engineering department of a university. We built an adjustable 500W h-bridge

Back in 2006 I was contracted to design a power amplifier prototype for the civil engineering department of a university. We built an adjustable 500W h-bridge based amplifier (operating between 50kHz to 300kHz+) which was used to drive transducers to create standing waves for waste water treatment, and it seemed to work alright in a bunch of our tests, but at fairly low flow rates. We passed the prototype on to the client (I think it was for a joint project between Monash University and Melbourne Water), not sure where it ended up. Great to see the technique being applied in consumer applications :)