[philso]

Devyash

You need to study up on the various types of motors available (DC, AC) and the advantages and disadvantages of each type. You then need to study the types of controllers available for each type of motor. Since you are aiming at maximum efficiency, you will have to select the motor and controller very carefully. As Tim above says, you need to have clear specifications for what you are trying to do before you start.

Adding regenerative braking will roughly double the complexity of your controller. It will also roughly double the losses in your controller while transferring power from the battery to the motor, reducing your overall efficiency. Unfortunately, I have yet to find a commercially available AC or DC motor controller for EV applications that has regenerative braking.