Research In Energy Management Strategy And Hardware In Loop Of The Controller For The Plug-in Hybrid School Bus

Plug-in hybrid vehicle is a compromise of pure electric vehicle and hybrid vehicle, it can run in pure electric mode saving energy and zero emissions, it can also run in hybrid mode, taking into account the needs of people’s long-distance running, along with the advantages of both, so it has good prospects. This paper developed a rule-based energy management control strategy, and has been build a model for the strategy to do an off-line simulation, set up hardware in loop(HIL) simulation platform for controller flashed control strategy to do HIL simulation. The main contents of this paper are:Complete the selection and matching of plug-in hybrid school bus powertrain structure. The selection and matching of the powertrain structure is the security of vehicle dynamic performance and the basis of economy, the selection of this paper considers the aspects of cost and dynamic performance potential, and makes a preliminary match by two indexes which are maximum speed and climb performance, and checks by acceleration performance index. The acceleration time from 0 to 50km/h is less than 15 s in electr ic vehicle mode and less than 20 s in hybrid mode, both of the acceleration time are less than the design requirement 22 s. It verifies that the match can meet the school bus dynamic performance requirements.Develop the rule-based energy management control strategy. Energy management control strategy is the basis of economy for plug-in hybrid school bus. According to the four principles of energy management control strategy, design the energy management control strategy contains EV, CD and CS modes, three modes corresponds to the battery state of charge from high to low in turn. And the switch between CD mode and CS mode is set to be reversible. When the battery power backs up to a certain level due to the engine generating electricity, it can switch from CS mode to CD mode. Extending the time of CD mode for the vehicle process in another way, which is fit with the global optimum theor y results, it’s in favor of enhancing vehicle fuel economy further.Complete the plug-in hybrid school bus vehicle and energy management control strategy modeling based on MATLAB/Simulink environment. By building the power unit models, battery model, driver model and energy management control strategy model of the vehicle model, in offline simulation environment, by velocity track, power track and So C curve and other simulation results, verify the developed control strategy effectiveness and rationality, control strateg y developed meets the design requirements in terms of dynamic performance, it can track the China typical city driving cycle well; it also makes a good performance in econom y, the diesel consumption and the electricity consumption are 15.3L and 10.7 k W ? h with the beginning of 85% power of battery in 19 driving cycles. It can make a reversible switch between CD mode and CS mode for the vehicle energy consumption mode, and extending the time of CD mode.Complete the CANoe&Simulink co-simulation based on CAN bus simulation environment. By splitting the vehicle powertrain system into each node model on CAN bus, simulate the operation of the control strategy in CAN bus environment, verify that the bus load is reasonable in the value 27.17% and the signal transmission and reception time meet the development requirements of the vehicle controller, the function of the control strategy is normal, the correlation coefficient between the results and the Simulink off-line simulation results is 0.98.Complete the vehicle controller development based on Moto Tron. Embed the control strategy to the Moto Hawk project and generate code by automatic code generation technology, and then download the code to the controller by the Moto Tune, and use Moto Tune to do online monitoring and calibration for the controller.Develop the HIL simulation platform for CAN bus simulation, monitor and calibration. Based on the "V" cycle control system development process, combine with the development process from virtual to real, verify the controller ’s function gradually. The results of the HIL simulation shows that the controller has the control function, and the velocity track, power track, mode switch, the torque of power units and other simulation results are consistent with the control strategy anticipation, it’s also corresponding to the simulation results in software level, the controller of the plug-in hybrid school bus has the robustness and the reliability.