Nothing easier. Obtain a 120V-to-your-voltage transformer.
On the pump, put the transformer right next to the pump, wire the transformer primary (the 120V side) to the pump motor. That side of the transformer will get to 120V+, so pot the heck out of it / double insulate it so nobody can get near those connecting wires.
Then, attach your low-voltage drive circuit to the secondary of the transformer.
This is called backfeeding a transformer. (this is how jackasses with home generators kill power company linemen, by the way.)
Anyway, you drive the transformer with your voltage at 50/60 cycles AC. Now, you don't need a full-wave inverter for this. You may be able to get off as cheaply as simply pulsing DC power to the transformer at your designated frequency. Or you can do a half-wave inverter, by using a center-trap transformer at twice your voltage (only requiring two gates and no negative power). You just have to play with it and see what works.
You may also be able to do even cooler things like VFD the motor, i.e. change the frequency to start it up or regulate its flow.