I'm building a mobile robot which is quite heavy and needs some serious HP. For this and other reasons I want to mount 4 induction motors to each wheel (for a total output of about 8kW) and power them via batteries. However, those motors need 3-phase current and I obviously can't plug them directly to the batteries. This is why I need a variable frequency drive but without the prepended rectifier (input current is already DC). I have been looking all around but couldn't find any devices that seem to be able to do just this. Can anyone with a bit more oversight maybe lead me into the right direction?