Electric vehicle gearshift analysis with synchronizer

The application of multi-speed transmissions in electric vehicles (EVs) continues to grow as a result of improved performance and driving efficiency in comparison to single speed EVs [1{3]. Traditionally, shifting and gear selection is performed with the use of friction clutches, a result of both limited controllability and high inertia of combustion engines. These friction elements are a major source of inefficiency in multi-speed gearboxes [4{6]. As electric motors are significantly more controllable than their conventional counterparts, as evidenced by paper such as [7{9], reliance on inefficient friction elements can be reduced, and even eliminated. This has resulted in the development of shift control strategies that rely on motor control rather than friction based strategies [10{12]. However, as shown in [13] these strategies cannot entirely eliminate the need for torsional vibration absorption during clutch lockup.