Modeling And Control Of Power Converter For Electric Vehicle

The situation of environmental pollution and energy crisis makes the new energy technology become a hot spot in the world. Automobile is an indispensable means of transportation in the city, and the development of electric vehicle becomes a more and more important issue in the new energy technology.This paper focuses on the research of DC/DC converter and the three-phase voltage type inverter power converter- in electric vehicles. Closed loop control DC/DC switch converter is adopted to realize high efficiency power conversion. The current control of three-phase voltage source inverter is realized by using the model predictive current control algorithm, and the fast tracking performance of three-phase voltage source inverter is guaranteed. Aiming at the problems such as delay, ripple and so on, the algorithm is improved, and the influence of these problems on the system is suppressed.(1) The working principle of DC/DC type Buck converter is analyzed,and the working principle is analyzed. Using the state space averaging method to model the system and analyzing the small signal system model, the transfer function of the system is derived, which provides the basis for the system control. The open-loop transfer function of the system was analyzed to determine the compensation network function type. The zero pole position of the compensation is determined according to the compensation rule, and the gain size of the compensation network is adjusted. Observe the phase margin size of the system near the cross-over frequency.The simulation model of Buck converter is built, and the control algorithm of compensation network is used to obtain good stability and dynamic performance.(2)The mathematical model of three-phase voltage source inverter is established, and the model predictive current control algorithm is analyzed theoretically, realize the control of the three-phase voltage source inverter model predictive current control algorithm. Aiming at the delay and current ripple of the model predictive current control algorithm, the improved model predictive current control algorithm is proposed to calculate the reference current. The load current of the system is predicted by the calculated reference current, and the current tracking is more accurate.The simulation model of three-phase voltage source inverter is built, and the model predictive current control algorithm and the improved predictive control algorithm are compared. The simulation results show that the improved algorithm can effectively track the current, the current ripple is reduced, and the system has good steady-state and dynamic characteristics.