Research Of Bi-directional AC/DC Power Converter Based On DC Micro-grid

DC micro-grid can effectively solve the problem of distributed power system’s access to power grid, not only improved power supply’s quality, reliability but also flexibly meet the customer’s diversified needs. As the core component of micro-grid power’s energy management technology, bi-directional AC/DC power converter greatly reduced the harmonic pollution to power grid when realize bi-directional flow of power electricity, the research of control technology about it is a hot topic in the field of power electronics currently.On the basis of comparing all types of bi-directional AC / DC power converter circuit’s structure and characteristics, the single phase bi-directional AC/DC power converter choosed as research object. Three different modulations of SPWM are compared and unipolar double frequency modulation is selected as the control technology, the circuit’s working modes are analyzed in detail under unipolar double frequency modulation method. Based on mathematical model’s analysis and control strategy’s research, the two different control strategy of voltage-current close loop control and one-cycle control’s research and analysis are carried on detailed. Under gived system’s indicators the two control strategies’ research are carried on MATLAB, simulation results verified the two control strategies’ feasibility. By comparing the results of theoretical studies and simulation results, concluded that one-cycle control strategy has better control performance than voltage-current close loop control. On the basis of theoretical and simulation’s research, 700 w bi-directional AC/DC power converter prototype of one-cycle control is built, which TMS320F28335 type DSP as it’s controller, the prototype’s hardware circuit design and software control scheme are introduced.Finally, experimental resualts and test data of one-cycle control obtained by experiment of the prototype, the experimental results showed that one-cycle control of bi-directional AC/DC power converter has good performance and characteristic, verified the rationality and feasibility of the theoretical research and design.