A Study On Switching Strategies For Matrix Converter

As a new AC-AC power converter, the matrix converter superior to others inmany aspects, such as, no large DC link capacitor discharge, controllable outputpower, four-quadrant operation and so on. Therefore, the matrix converter is favoredby research scholars at home and abroad, And with the development of powerelectronics and power electronics, and demonstrate its potential applications, thetopic is of great significance. This paper studies the high performance of spacevector modulation of he matrix converter, more details are as follows:(1) The basic principle of the matrix converter and the modulation strategy ofmatrix converter are in-depth analyzed. On this basis, aimed at the impacts on theproperties of the matrix converter, which is brought by the orders of the activeswitching vector and position of the zero vector within a switching period, fourdifferent switching modes are proposed and switching tables of the four are deduced.The low-distortion eight-switching mode, a newly proposed mode, not only reducesthe number of commutation in a period, but also reduces harmonic distortioneffectively.(2) A new harmonic analysis method is proposed based on the selection ofmatrix converter space vector modulation factor has great influence on harmoniccontent. the method were used in the above four switch mode, obtained the harmonicflux mathematical model for each switch mode, and analyzed on MATLAB. In thecase of different modulation index and input-output displacement angles, a3Dgraphic of values of the RMC flux is obtained, the actual study be provided areasonable basis about the selected parameters.(3) Four identical schematic diagram modules of the four-step commutationare built by the logic devices in MATLAB/Simulink. They work respectively assignals generator of the switch of three-phase input-one-phase output unit to drivethe actual switches of the matrix converter. Complex modes of voltage open-loopand closed-loop of the four switch modes are built respectively by using S-functionof C language programming. Thus, the S-function realizes the corn control strategy.The simulation testifies the feasibility and superiority of every switch mode underthe space vector control of the matrix converter. The harmonic of output voltage inclosed-loop control is lower than in open-loop, also, the distortion of the input-current and the output-voltage decrease. This simulation model matches muchto a real system, especially S-function programmed by C language speeds up thesimulation and the closed-loop control lays solid foundation for the development andcontrol of the high-performance prototype matrix converter.(4) Based on the simulative analysis,using TI’s TMS320F28335as the core, aprototyping system of the matrix converter is designed and built,and the maincontrol board for DSP and CPLD is made.It testifies the four-stepcommutation,designs the software of the system,and laids the foundation of thefurther experiments.