| With the problem of energy shortage and environmental pollution becoming more and more prominent,new energy vehicles become the future development direction of automotive industry. Among the various new energy vehicles, Plug-in Hybrid Electric Vehicle(PHEV) has distinctive advantages at this stage. It can not only reduce fuel consumption and emissions largely but also have long range.Electromagnetic transmissions is a brushless CVT(Continuously Variable Transmission), which is a key unit of hybrid system. Because of its special structure and working principle and the special application background of hybrid system, new requirement for its control is proposed. Besides, fuel economy and low emissions demand a reasonable energy distribution.Firstly operating principle of the electromagnetic transmission are analyzed. The characteristic of electromagnetic transmissions is analyzed using graphic method and operating state as well as power flow of electromagnetic transmission is obtained.Working principle of the electromagnetic transmission is analyzed and power relationship between those ports is gained. Working modes of hybrid system is analyzed, which is the base for system control and making EMS(energy management system).Secondly, control strategy of hybrid system based on the electromagnetic transmission is proposed. The math model of the electromagnetic transmissions system is established. In order to avoid lossing torque transmission capability in the situation that there is large speed discrepancy between output terminals of powertrain and engine, field weakening control method for electromagnetic transmission is studied, and simulation results indicate that the proposed strategy obtains good results.Besides, the coordinated control strategy of electromagnetic transmission system is presented, and simulation results in several modes prove that the system is controlled well.Thirdly, in order to improve economy while meeting the dynamic performance, EMS is investigated. Basic knowlege of fuzzy logic control is introduced, then principle of EMS is analyzed, and driving fuzzy logic controller and braking fuzzy logic controller are designed.Finally, in order to test EMS, simulaion model is estabished using AVL Cruise and run in NEDC cycle and UDDS cycle respectively. Simulation results indicate ICE operate along its optimal curve and battery is controlled optimally. Besides, in order to estimate performance of the proposed EMS, the comparison with test resule of Prius2012 is carried out, and reult shows that energy consumption is very close, which verifies good performance of EMS this paper proposed. |
PDF Full Text Request