Research On Electric Vehicle Motor Drive System Based On Trans-Z-Source Inverter

The electric vehicles as the main force of the new energy vehicles, which leading the development direction of the global automotive industry. The electric motor is the power source of electric vehicle, and its output characteristics affected by the battery voltage. The battery provides power to the motor, because of traditional power supply mode does not have the boost function, battery will cause a great voltage drop under the condition of automobile starting, rapid acceleration or insufficient of battery storage, which will make the output characteristics of the motor is not smooth and the power performance is limited. The thesis has designed an inverter with buck / boost function based on Trans-Z-S network to solve this problem and the main research contents are as follows.Firstly, based on the topology structure of Trans-Z-S inverter, the working principle of the inverter and the small signal mathematical model are analyzed. An improved Space Vector Pulse Width Modulation method (SVPWM) control strategy is proposed to solve the problem that the traditional control strategy causes larger inductor current ripple. More than this, the improved control strategy has good output characteristics of inverter voltage.Secondly, the problem of power-supply drive system of electric vehicle is analyzed, and the influence of DC voltage drop on the mechanical characteristics of the motor is discussed. The fuzzy adaptive PID control algorithm is adopted to realize the closed-loop control of the Trans-Z-S inverter, which enhances the dynamic adjustment ability of the Trans-Z-S inverter.Finally, the design method of capacitance and inductance parameters of Trans-Z-S network is given based on the inductor current ripple and capacitor voltage ripple,the rationality of parameter selection is guaranteed; An improved SVPWM control strategy model is established in Simulink, and a three-phase inverter is built based on the network parameters to verify feasibility of SVPWM.The closed-loop control model of Trans-Z-S inverter is established in Simulink and the validity is verified through simulating self-regulating process of the whole system when the DC input voltage decreased.Simulation and experiment results verify the feasibility and validity of the Trans-Z-S motor closed-loop control system in the field of electric vehicles.