Smooth Mode-Switch Control for the Powertrain of Parallel Hybrid Electric Vehicle

The coordinated control of internal combustion engine and electric machine is vital to improve driveability and reliability of Parallel hybrid electric vehicle (PHEV). This paper address to the mode-switch problem for powertrain of PHEV, construct a model-based rapid control prototype as a controller by MATLAB/SIMULINK software and dSPACE system for mode-switch control, come up with a mode-switch control strategy which employ the quick transient response of electric machine to compensate the deficiency of transient torque performance of internal combustion engine. Aiming at the general characters of mode-switch, a experiment schedule was implemented on the PHEV test bench, Comparing to the control method by estimating the engine toque with steady torque map, the experiment result show that the control strategy proposed in this paper can reduce the torque and speed fluctuation significantly during the course of mode switching in PHEV. Keywords-parallel hybrid electric vehicle; mode-switch; control strategy I. INTRODUCTION Hybrid electric vehicle gets high attention of researchers and automobile factories currently due to it's feasibility of mass production as well as low emission and high economy. Energy management strategy and the coordinated control of multi mechanical power sources are the two key problems for HEV. Energy management strategy has been researched widely(1), but for the other one, far less reports are presented. Some studies on this problem has been done just by simulations(2),(3). This paper address the smooth mode-switch control for the powertrain of PHEV by experiment to improve the driveability, comfort and reliability of PHEV. The second part of this paper will explain the control problem addressed by this paper; the third part presents the control strategy; the forth part focus on the way how to get the real time engine torque and construct the rapid control prototype of parallel hybrid powertrain by MATLAB/SIMULINK; the fifth part introduces the test equipment; the sixth part gives out the experiment method, test results and discussion; finally some conclusions are made in the seventh part.