The Research On Three-phase AC/DC Matrix Converter

Matrix converter has many good performances. It permits frequency conversion in a single-stage processing without large reactive energy storage components, the input fundamental displacement factor nearly at unity or freely varied regardless of the load power factor, and allows bi-directional power flow. Matrix converter is a flexible and universal power converter by itself. Several topologies can be reduced by this converter. A novel AC-DC power converter reduced by AC/AC matrix converter is investigated in the paper, besides general feature, it has other characters different with existing rectifiers. Combined with computer simulation and prototype experiment, a kind of matrix AC-DC power converter was deeply investigated in this dissertation.The circuit topology of AC-DC matrix power converter is fully researched in the paper, present two different converter structures, DC load can be isolated with power supply by one topology, the others is a direct convert structure. Direct convert structure is focused on in the paper, four different topologies can be evolved from the direct structure, one of them with four-quadrant operation capacity is deeply researched in the paper.Two control strategies of AC-DC matrix converter, switching function and current space vector modulation, are investigated. Under distorted or unbalanced power voltage, switching function and current space vector modulation are deduced and their influences over converter performances are investigated individually. Based on the principle of switching function parity, the uniform relationship is established in the two algorithms. By researching the common voltage in the converter, present a method which can effectively decrease the common voltage.The static circuit model of matrix three phases AC-DC converter is established, the power characteristics and its four quadrants operation capability are investigated systematically. Based on the system static model, the dynamic circuit AC small-signal model is established by moderately asymmetrical linearzed method. The stability and dynamic performance of the converter are investigated systematically.Safety commutation in matrix AC-DC converter is researched. Multi-step commutation methods in matrix converter design and their negative effect on the converter performances are analyzed. One-step commutation method adopted in the converter design matches the operation characteristics of AC-DC matrix converter. The logic and control circuit of one-step commutation is realized.In order to further studies on the converter performances and experimental research, the simulation model of the AC-DC matrix converter is established. Based on the model, the control and operation performances of the converter are simulated entirely. The correctness of theoretical analysis is proved by simulation results.The experimental platform of the converter system is established. Based on the platform, experimental research is carried out. Experimental results accord with the simulation results well. The correctness of theoretical analysis and the validity of design scheme are proved by experimental results, which found the basis for the matrix converter's further practical studies.