Development Of Digital Control Bi-Directional Full-Bridge DC/DC Converter Based On DSP

Bi-directional DC/DC converter (BDC) is such a typical device as "two functions in one device", with which energy can transfer in either direction. So, using BDC can reduce the size, the weight and the cost of power system, and it is worth while to research. The thesis mainly concentrated on the research of the digital controlled, isolated bi-directional full-bridge DC/ DC converter which can be used in high power applications.First, the conception, applications and research of the bi-directional DC/DC converter are presented. And on this basis, advantages and disadvantages of the voltage-current bi-directional full-bridge DC/DC converters are studied and analyzed. Then the voltage-voltage bi-directional full-bridge DC/DC converter is brought in. The high side and low side of voltage-voltage bi-directional full-bridge DC/DC converter are all voltage full-bridge structure. In buck mode, high side switch in possession of driving signal, and switch drive signal of low-pressure side is blocked, which has only body diode of switch to be used as rectifier. In boost mode, the situation is just reversed. So, the buck and boost mode of the voltage-voltage bi-directional full-bridge DC/DC converter are similar to a single full-bridge DC/DC converter. The magnetic bias problem of high-frequency transformer is analyzed and the solution is given. At the same time, the main circuit, the driving circuit, the sampling circuit, the protecting circuits and the auxiliary power supply circuits are designed based on the analysis of operation principle on voltage-voltage mode bi-directional full-bridge DC/DC converters, and the way of calculating and selecting the component parameters and the design flow of magnetic components such as transformer are also presented. In addition, the simulation of the main circuit is carried out by the OrCAD10.5/PSpice software. In this paper, because the digital control method which is based on DSP TMS320F2812 is adopted, so, a direct digital phase-shift method based on DSP full comparison is put forward, and by the way of programming, the phase-shift waveform can obtain and the dead-time can be set.Finally, a prototype with ration power 1kW is made. The experimental result shows that the scheme, analysis and the design are correct.