Increasing efficiency of ecological vehicles by integrating auxiliary units directly to the traction shaft

The climatisation requirements of Electric Vehicles (EVs) largely depend on its usage location. For example, EVs operated in European countries require heating during the winter season, while those operated in equatorial regions face cooling load throughout the year. To date, the low range for a given battery charge remains the single-most important factor hindering the widespread acceptance of EVs. The principal electrical loads of an EV comprises of the traction and air-conditioning (A/C) compressor motors. These high power loads expedites the battery drain, leading to poor cruise range. The paper proposes a novel design solution geared towards improving the overall operating efficiency of these motors by integrating them into a single housing. The integrated unit is expected to operate close to 100 % efficiency during recuperation mode. The unprecedented improvement in efficiency is achieved through direct mechanical coupling of the traction motor with the A/C compressor during breaking events. The mechanical configuration of the unit is such that the torque and speed characteristics of traction and compressor motors can be independently controlled during drive mode. In addition to improved efficiency, the integrated unit boosts numerous other advantages such as increased reliability, compact design and weight saving.