Research On Control Strategy Of E.T.Driver Based On AMT In Parallel Hybrid Electric Vehicles

The integration research of hybrid power system of hybrid electric vehicle (HEV) is the key research emphasis at home and abroad, and the trend will still prevail in the future.Hybrid power system is the central component of HEV. The performance of HEV is greatly achieved by the capability of hybrid power system. How to efficiently achieve the integrated control of HEV and to make the whole power configuration become highly integrated and simple are the key point and difficult point for research. Now, the hybrid power system has already been developed from a discrete structure into an integrated one, which is called the integrated hybrid power system in past ten years. The integrative hybrid power system can well represent the optimization idea of HEV and it is also the most difficult structure for study, which has the most complexity and the most diversity. So it will always be the important research emphasis even in the coming several years. As for the integration research of transmission (gear box) and motor, also called transmission system integration, there is still no research in this field both in China and other countries. This dissertation presents the idea of E.T.Driver (electric Transmission Driver) for the first time. The E.T.Driver integrates the transmission and permanent magnet synchronous motor into a compositive hybrid power unit system, which can perform shift, generate electricity, regenerative braking and drive function. The main research of this dissertation is the E.T.Driver, which integrates AMT (Automatic mechanical transmission) and a permanent magnet synchronous motor into a hybrid power system. In the E.T.Driver based on AMT, the permanent magnet synchronous motor is mounted on the output shaft of AMT and the rotor of permanent magnet synchronous motor is coupled with the output shaft of AMT directly or with a coupling device. The E.T.Driver based on AMT can perform the drive, generation of electricity, regenerative braking and power transmission function. The gear shift quality, including shock intensity and slipping friction work, is the most important appraisable target during the gear shift phase. This dissertation mainly makes a deep research on how the E.T.Driver improves the gear shift quality, driving smoothness and riding comfort during the driving shift phase and start-up gear shift phase.The index of slipping friction work is incompatible with that of shock intensity. In order to form an integrative optimization between shock intensity and slipping friction work, different gear shift control strategy have been made to find a compromise between shock intensity and slipping friction work according to different work condition of E.T.Driver. Under the condition that the driving torque of E.T.Driver is larger than or equal to the resistance torque, the flywheel has enough time to track the rotational speed of the friction clutch plate, because the E.T.Driver can provide enough driving torque to assure the driving torque of vehicle is not interrupted during the clutch detachment phase. When the rotational speed difference between the flywheel and clutch disk plate is small enough, that is to say, the rotational speed difference between the flywheel and clutch disk plate is smaller than what is set in advance, the flywheel and the clutch disk will engage as quickly as they can. So the shock intensity and slipping friction work are all very small when the clutch engages with the flywheel. When the driving torque provided by E.T.Driver is smaller than the resistance torque, the multi-objective optimal torque control strategy, based upon the minimum value principle, is adopted to compromise the shock intensity and slipping friction work and make them to reach an integrative optimization. The optimal torque control function is derived and described by an analytic function.The gear shift operation can be finished under the condition that the driving torque is not interrupted. Furthermore, the gear shift quality, driving smoothness and riding comfort also can be ensured because of the special structure of E.T.Driver, combining the corresponding optimal torque control strategy presented in this dissertation. Besides this, the especially important thing is the E.T.Driver can output positive driving torque and also can output negative torque for electricity generation, which can well harmonize the coefficient value of weight function Z. This can ensure the gear shift quality to attain optimization.As an important part of the dissertation, the virtual prototype simulation and the practical on-vehicle experiment for the E.T.Driver are made. The virtual prototype simulation is modeled by SIMULATIONX and CRUISE software and verified by practical vehicle experiments. The practical on-vehicle experiments can gain theory basement and data contrast from the simulation model by analyzing the simulation results. The road experiments of hybrid electrical bus equipped with E.T.Driver are carried out according to the standard of China, and mainly attention is focused on typical difficult working conditions, such as small throttle start-up gear shift, gear shift during acceleration course and high gear position. From the final simulation results and road test results, it can be found that the special structure and the corresponding control strategy of E.T.Driver can greatly enhance the gear shift quality, driving smoothness and driving comfort of HEV compared with the traditional AMT. With the optimal torque control strategy presented in this dissertation, the E.T.Driver achieves good dynamic character, which is adaptive to time varying driving condition of HEV and complicated surroundings. The research of E.T.Driver can greatly promote the development of automobile industry and HEV's key technology.