My thoughts so far have been to pulse the transducer at 40kHz using +18V on one side then -18V on the other (so total 36V then ground then 36V etc).
To do this I was going to use MOSFETs connected to a bench power supply and using a Microcontroller to provide the timing pulses (connected to gate of MOSFETs, via an amplifer(s) if needed).
Will this work?
My other idea was to use two sine waves out of phase with each other (180deg) across the transducer in a push-pull way using 2x30W power audio amplifiers.
Are these ideas along the right track?
Can anyone provide any insight on how to drive these correctly?
My other idea was to use two sine waves out of phase with each other (180deg) across the transducer in a push-pull way using 2x30W power audio amplifiers.
Here I think I know what you mean. Look for "BTL" = bridge tied load.
But for your first solution I need a drawing of how you want to build it.
Maybe you want it to be square wave instead of pure sine.
Then a half bridge may be used (0V / 18V at the load) or a full bridge ( +/-18 V at the load, similar to BTL)
Square may have a benefit against pure sine wave regarding cleaning effect (overtones). You should read about this.