Research On Bi-Directional DC/DC Power Storage Converter Based On Digital Control

The power grid in China now is faced with numerous challenges such as the continuous increasing of the top power load, the expansion of the ratio for the interrupted energy inserted and also the puzzle of the limited methods to regulate peak values. And these problems will certainly make bad effect on the safety and stability of the electrical field. For this reason, applying batteries with large capability to store the the power energy becomes urgent, which will remit the large demand for electrical power, enhance the safety and stability of power grid, improve the quality of power energy, and also will Boost the development and utilization of the sustainable energy. The energy-storage converter is the keypoint of the energy-storage system, and the platform for the converter control system could affect the accuracy, reliability and respond speed of the energy-storage system. Therefore, studying on this problem has not only the theoretical importance in theology, but also the practical significance.Based on the reading and the analyzing of domestic and foreign relative literatures, the design objective of the system was established and the Bi-directional half bridge topology was selected. Based on the basic Buck and Boost circuits, this paper detailed the principle of the half bridge DC/DC power storage convertor and the structure principle of the Interleaved three phase topology composed of this basic unit in parallel connection as well as its analysis of its advantages.According to the design requirement, the component parameters of the Interleaved three phases Bi-directional DC/DC converter were committed. And then the simulation models of the power circuit and it's control system were built with a simulation software PSCAD. The result shows that the parameters of the components designed above were reasonable and guides the direction of the debugging the PI parameters in the experiment. Based on this, a real system of a Bi-directional DC/DC converter to be realized was discussed, mainly including the design of the hardware and the software.At last, the experiment for the Bi-directional DC/DC converter was carried out by using resistant as the fake batteries load. The result shows that:under the same condition with a same size inductance, the ripple voltage and the ripple current in the Interleaved three phase Bi-directional DC/DC converter are less than the single phase one. Meanwhile, the Interleaved three phase topology enhance the switch frequency, and due to its parallel connection of the half bridge structure, the current stress of the switch transistor was released and the capacity of the system was increased. The result also shows that, the Interleaved three phase Bi-directional DC/DC converter designed in this paper meets the design requirement.