Design And Research Of Interleaving Bidirectional DC-DC Converter

With the increasing of power energy demand, the existing power energy systems would be hard to meet the demand. However, the increasing conversion efficiency in new energy makes clean and renewable resources can be used efficiently, rapidly improving in the energy storage technology makes these unstable energy easy to storage. Bidirectional DC-DC converter is the core component to link energy storage system and power supply system, transmission for electric energy storage and release. This requires bidirectional converter conversion output characteristic is stable and high efficiency. The interleaving technique can increase the equivalent switching frequency, reduce the filter parameters to optimize output characteristics, improve the power density. This paper uses interleaved bi-directional DC-DC converter design based on micro grid technology. The main research contents are as follows:Describes the working mode and control method of bidirectional full bridge converter and the interleaved bidirectional converter, analyzed each advantages and disadvantages using in the micro grid. Analysis the ripple characteristics of interleaving topology, explained the relationship between current ripple and number of interleaving and working condition. Pointed out that in the different scope of work conditions need to select the appropriate number of phase interleaving. Analysis of the current share characteristics of interleaving, staggered that each phase current share is mainly affected by the duty and parasitic resistance parameters of each phase inductance. Designed the main circuit parameters of bidirectional converter.The converter is modeled by use the state average method, find out small signal model of the buck and boost circuit, advantageous to the controller design. The introduction of the SISO TOOL MATLAB design tools, design a reasonable PID parameters, the open-loop characteristics with certain amplitude and phase margin, make the control loop maintaining the stability and achieve good dynamic effect.The detection and control circuit design, including signal acquisition, digital control, communication module, control and drive output. Each part of the circuit are discussed in detail the scheme, analysis of advantages and disadvantages of each module design, circuit structure suitable choice.Analysis of control strategy for bi-directional converter, according to the design requirements to produce a prototype 10 k W. The simulation circuit of micro grid are tested on the prototype, the test results show that the interleaving scheme is feasible and the analysis of its theory.In summary, this paper analyses working characteristic of interleaving topological structure, and the small signal characteristics of the loop, and to use the bidirectional DC-DC micro grid as the background of the prototype, and provide the basis for further improving the working performance and transmission efficiency of bidirectional converter.