Research Of Pure Electric Vehicle Motor Controller

With the development of society and economy, Cars have become an important means of transport for us. The enviroN·mental problems caused by traditional fuel car demand for petroleum resources have attracted us attention. Electric vehicles have many advantages, such as non-exhaust emissions, high energy efficiency, low noise, more energy for recovery. Development of electric vehicles can effectively solve the problem of energy consumption and enviroN·mental pollution.This paper intends to carry out a deep research on light electric vehicle motor controller. Developed a motor controller with the advantages of perfect hardware protection function, reliable heat dissipation structure and low cost. The separate excited motor controller was developed at first. During the development process, several key technologies were analyzed, such as the design of power circuits, heat sink and the control strategies development as well as kinds of hardware and software protection functions. Based on this, the asynchronous motor controller was developed.Firstly this paper analyzes the research background of electric vehicle motor controller, research significance and development trend, And determine the direction of this subject. Select Power MOSFET as the power switch after comparing a variety of power devices. Introduce Power MOSFET parallel flow characteristics, Then study on the influence of parallel flow characteristics using NI Multisim electronic circuit simulation software. According to the results of simulation, motor controller power module is designed which is using parallel-power-MOSFET method adopted in the main circuit. At the same time drive circuit and the hardware protection circuit is designed. Secondly, because of the Power MOSFET can generate loss during the process of the switch, and distributed in the form of heat, if heat dissipation is not good the Power MOSFET will be damaged. At present there is not too much study at about power device heat sink design for electric vehicle motor controller. This paper analyzes the power MOFET thermal path, calculated the heat sink thermal resistance, and design a reasonable heat sink through electronic equipment thermal analysis software Qfin4. Thirdly, a complete hardware control circuit is designed, Micro controller chooses is a16-bit freescale microcontroller MC9S12XEP100which is Auto level chip, and do a lot of experimental to verify the control strategies for separately excited motor. Finally, according to the experience of develop DC motor controller combined with the characteristics of AC asynchronous motor, the final design is an AC asynchronous motor controller which has the advantage of perfect hardware protection function, low cost and reliable cooling structure.