Voltage Transfer Characteristic And Harmonic Analysis Of Matrix Converter

Matrix Converter is a new type of AC-AC power transmission. It is one of focus in the field of power research. The research of the ratio of transfer is lower than 0.866 in the domestic or in the foreign. and there is no special all-sided research of the characteristic of voltage transfer. The harmonic of input current and output voltage is not analyzed because of modulation strategy.The ultimate target of the research of Matrix Converter is to find switch combination and switch function. To solve the low transfer ratio problem, the over modulation strategy of Matrix Converter is put forward. The modulation zone is divided into two zone: linear zone and over modulation zone. Two over modulation strategy is adopted in the over modulation zone. The wave of output voltage is smooth from sine wave to six-step wave. On the basis of theorem of the mean, the essential of the modulation strategy is to adjust duty ratio of double line-voltage. At the same time the spectrum of the output voltage is analyzed with FFT. The maximal voltage transfer ratio is 1.0. The switch function is analyzed with FFT in the equivalent circuit. switch function is divided into high part and low part. The relation of the high part of switch function with the high part of input current is analyzed. From the relation The conclusion is draw the high part of harmonic content is inverse to switch frequency.The harmonic of output voltage arise because of output voltage wave itself and modulation strategy. The switch frequency is increased. So the harmonic content of output voltage mostly concentrates on the high part. The filter easily eliminates the harmonic.Simulation model is set up with the means of MATLAB/SIMULINK to prove the control strategy. The result of simulation is same with the theory analysis. Moreover the device is designed and debugged.