Research Of Electric Vehicle Bi-directional DC/DC Converter Based On DSP

As the energy shortage and environment pollution are deteriorating, electric vehicles have drawn wide attentions because of their great advantage in technology, environment protection and energy saving. It is well known that bi-directional DC/DC converter is an indispensable component of electric vehicle, and plays an important role in the electric vehicle—energy bi-directional transmission and stabilizing voltage, it can optimize motor control, improve efficiency and performance of electric vehicle. Therefore, development of a high-efficiency and high-power density of bi-directional DC/DC converter for electric vehicle is of great significance.In this paper, the soft-switching is achieved and high-efficiency is obtained by using the bi-directional DC/DC converter topology. After introducing multi-phase interleaving technique and magnetic coupling technique on half-bridge DC/DC bi-directional converter, a four-phase interleaving bi-directional DC/DC converter based on coupling inductor is presented, it has the following advantages:switches have smaller current stress and realize ZVS capability over a wide load range, current ripple can be reduced, having good steady-state and dynamic performance and suitable for electric vehicle applications.Firstly, in a brief introduction of the bi-directional DC/DC converter research status and development trend, this paper detailedly analyses the working principle (including topology, operating modes, operating principles and achieve ZVS soft switching) of the four-phase interleaving bi-directional DC/DC converter based on coupling inductor, establishes magnetic models of the two coupling inductors and produces its formula of coupling coefficient.Secondly, according to subject requirements and digital microprocessor control system performance requirements, this paper determines the technical parameters of the bi-directional DC/DC converter and chooses DSP TMS320F28035as core controller. Based on this, the high-side400V and low-side250V16kW main circuit (including coupling inductor design and manufacture, power MOSFET selection, snubber capacitor design input and output filter capacitor design), control circuit (including driver circuit design, sample conditioning circuit design, protection circuit design, and auxiliary power supply circuit design) and software system (including ADC software design, PWM software design and digital PID controller design) are designed detailedly.Finally, this simulation models of the converter are established using the software Saber and a16kW prototype are fabricated. Simulations and experiments show that theoretical analysis and prototype design of bi-directional DC/DC converter is correct and feasible.