The Research On Drive System Of Electric City Bus Based On EMT

With the increase of vehicle population, the environmental pollution and the problem of energy shortage become more serious. So the development of clean-energy vehicles becoming the focus of auto companies and research institutes. Under intense analysis of the global car industry, I come to a conclusion that electric vehicle is a feasible route to realize the new energy industry at the present conditions.The performance of electric vehicle is largely depend on its drive system, and which also is major difference between traditional car and electric vehicle, so the research in electric vehicle is now focused on the drive system. Electric automated Mechanical Transmission (EMT) is a power system which special for electric vehicle, using the shifting way of Motor adjust speed, and EMT no longer use synchronizer ring. So EMT Can realize high quality shifting which is the quickly, accurately and having small impact. EMT drive and shift by the same motor, and it integrates the motor and transmission together. So the system has small weight and volume. This makes it is convenient to arrange the system in the vehicle, and it reduce the quality of the vehicle, reducing the unnecessary energy consumption.Based on the electric vehicle bus project from Dong Feng Yangtze Bus Company, the drive system of electric vehicle bus was researched. The job of the project is to convert the WG6120 by replacing the drive system. The paper focuses on the structure and working principle of EMT, and analyzing the advantage of EMT in the using in electric buses. By the research of the composition of electric vehicle drive system, motors, batteries and transmission, summarized the advantages and disadvantages of each type. In this paper I complete the selection of all part of the drive system according to design requirements and the actual working conditions, and complete the calculation of all parts of the system when choosing parameters based on the parameters of WG6120.The control of electric vehicle which is one of key factors that determine the performance of electric vehicles can impact the energy efficiency of electric vehicle. In this paper the composition of electric vehicle control system is researched and the control principle of all part of the driver system of electric city bus that based on EMT comes on. Through the design of free port communication between PLC and CAN485MB CAN bus protocol converter realize CAN communication of electric vehicle controller, which greatly improving the real-time and reliability between the control units in data exchange, and the control strategy of the driver system of electric city bus that based on EMT comes on depending on the characteristics of the motor and the actual conditions. The method of distinguish the difference between several braking comes on after the research in different braking, and regenerative braking strategy which full consideration to safety when braking comes on.