Inverter
An inverter, in an EV traction drive usually called a traction inverter, is the power electronics that converts high-voltage battery DC into controlled multiphase AC for the motor and manages reverse power flow during regenerative braking.
What it controls
Semiconductor switches rapidly connect each motor phase to the positive or negative side of the DC bus. By varying the switching pattern, the inverter controls phase voltage and current, which lets the motor controller regulate torque, speed, and regeneration while enforcing electrical and thermal limits.
The inverter is not the same component as the onboard charger or DC-to-DC converter. It is also not the source of the driver's torque request: higher-level vehicle control supplies that request, and the motor-control system turns it into current targets and switching commands.
For the detailed circuit, control, semiconductor, efficiency, cooling, and protection trade-offs, see Traction Inverters in Electric Vehicles.