Suitability analysis of in-wheel motor direct drives for electric and hybrid electric vehicles

In most conventional EV applications, a central high speed electric motor is mechanically coupled to the wheels by a single speed reduction gearbox and a mechanical differential. An innovative alternative utilizes low speed, high torque, gearless, electric motors, mounted completely inside the rim of the wheels, to provide instantaneous torque and eliminate driveline transmission losses. These in-wheel motors have many advantages, including no mechanical linkages and independent and precise torque control of each wheel. Furthermore, advanced control functions like Antilock Braking System (ABS), Anti Slip Regulation (ASR), Electronic Stability Program (ESP), and steering assistance can be easily integrated. In this paper, various motors and control strategies for such in-wheel motor drives for 2-wheel and 4-wheel drive vehicles have been presented.