Research And Realization On7.5kw Back-to-back Converter Control System Based On DSP

With the problem between energy and environment has become increasinglyprominent, the electricity load presents diversity characteristics in different areas, thetraditional grid electricity load has been unable to meet different needs. Therefore themicro-grid technology is becoming research hotspot and key problem in electricpower and electric related areas. As a core part of the micro-grid, back-to-backconverter technology has been concerned. The back-to-back converter has beenwidely used in the field of renewable energy distributed generation and the micro-gridapplications, because of it can achieve the function of controlled interactionAC-DC-AC energy at both ends with the advantages such as adjustable power factor,small harmonic output current and two-way flow of energy etc.In this paper, a three-phase back-to-back converter control system is used for thestudy. The theory study, the debug design and the final system implementation of thesystem are completed. Firstly, according to the requirement of design, the systemfeasibility study is completed and system design scheme is determined, based on theanalysis and summary of the three-phase back-to-back converter research status anddevelopment trend at home and abroad. Secondly, The key technology workingprinciple of three-phase back-to-back converter is expounded. Considering AC loadcharacteristics, applying control stratgies of vector transformation and SVPWMmodulation technology, the permanent magnet synchronous motor mathematicalmodel is set up and control strategy is researched, based on the coordinatetransformation thought. system joint debugging between the grid side and the loadside is taken into account, research on system startup logic control and coordinatedcontrol strategy is required.On this basis, accroding to the system design schema, the main parameterscalculation and circuit design of system hardware are illustrated in detail, theparameter computing method of AC inductor and DC capacitor is proposed, thedesign scheme of main circuit unit is raised. Based on the control strategy of thethreephase back-to-back converter control, using DSP (TMS320F2812) as the core ofthe control system, the software structure of Control system is designed and thesystem software programming is completed. Using MATLAB Simulink simulationsoftware verified the validity of the system design.Lastly, setting up the experimental platform which can afford the requirements ofthe three-phase back-to-back converter system is inturduced in this paper, while theoverall system debugging data and real-time waveform are analysised. Above of allverifies the feasibility and correctness of the design of the threephase back-to-back converter system.