HEV Application of Shaking Vibration Control System Based on Advanced Motor Control

A hybrid system that has been put on the market by Nissan Motor Company was configured by removing the torque convertor with a lockup clutch from a conventional 7-speed automatic transmission and installing a clutch and a motor in its place. This hybrid electric vehicle (HEV) has a simple structure and is expected to improve fuel economy and responsiveness because it eliminates the torque convertor. One issue for this system is that an abrupt change in the input torque could cause torsional vibration of the drive shaft, resulting in a severe degradation of ride comfort. To solve this problem, an original vibration control system that was adapted for the mass-produced LEAF electric vehicle was also adapted for use on this HEV fitted with an engine and a 7-speed automatic transmission. This control system enables the hybrid vehicle to generate maximum motor torque at launch and also provides significant advantages for vehicle design. Moreover, the hybrid vehicle can still provide its intrinsic benefits even when strongly accelerated by adding the motor torque to the engine torque. Therefore, this unique vibration control system contributes to both fuel economy and drivability. This paper presents the results of verification tests that show the good control performance achieved with this vibration control system.