The Theory And Experimental Study On Chaotic Characteristics Of Motor In Vehicle Electric Propulsion System

Electric Vehicle (EV) electric propulsion system, which is consisted of electric motor system and mechanic transmission system, is the core of EV. Research shows that chaotic phenomenon appears during the working condition of motor and mechanic transmission equipment, which will bring bad influence on vehicle such as the durability of vehicle and the safety of driving. So the mechanism, feature recognition and suppression method of its chaotic phenomenon should be studied. As the power source of vehicle, the research on its chaotic characters is the foundation of the research on vehicle system coupled chaotic characters. The study of the generating condition of chaos can be helpful to let the motor be far away from chaotic area, and to suppress the chaotic phenomenon. For generating chaos is the base of the above studies, the study of chaotification of motors not only be helpful to figure out the reason that lead motor into chaotic situation, Thus it will be of guiding significance of the design of the controller, what’s more, chaotifying motor can also simulate the chaotic state of the vehicle motors in virtual situation, and supply the chaotic power source of the vehicle couple chaotic character study test platform.The main points of the thesis are the research focused on the chaotic properties of permanent magnet synchronous motor (PMSM) and brushless dc motor(BLDCM) both of which are widely used in electric vehicles, and the method to make the motor of vehicle system coupled chaotic properties research test platform produce chaotic power resource.The work of this study is summarized as follows:First, the background, purpose, significance, the domestic and foreign research conditions of chaotic properties and chaotification on motor is introduced.Second, the mathematic model of PMSM, BLDCM is built under the d-q axis system, by affined transformation and time scale transformation, and the model which is convenient of chaos study is formed. For Hopf bifurcation condition, the chaos parameters of PMSM and BLDCM are analyzed.Third, the chaotification methods such as indirect and direct time delayed feedback method are introduced, which is used on PMSM and BLDCM. Based on the principle of bus voltage speed control, a Two-phase conduction state brushless DC motor chaotic model is derived. This motor is chaotified with the indirect time delayed feedback method, thus the chaotic speed of motor could be controlled in the expected range.Forth, a BLDCM test platform with no load is built by LabVIEW and NI-USB data acquisition card. The experiment is designed, and the result verifies the method, so the simulation of the vehicle drive motor is realized.