Research On Modulation Strategies And Performance Of Matrix Converter

Traditional AC/AC converters have many disadvantages, meanwhile people ask for higher requirement of power quality, so the research on matrix converter is getting more and more. In this paper, the mainly research is based on three phase to three phase direct matrix converter. The identical characters and differences between three usual voltage modulation strategies are studied so that we can choose one to get better performances.After introducing the basic theory of matrix converter, this paper analysis the modulation principle, characters and switch sequences of Venturini method, Optimized Venturini method(optAV), Instant Double Line Voltage method(INST) and Space Vector Modulation method(SVM). At last, seven SVM switching sequences because of different distribution of Zero Vectors are concluded.On the basis of Indirect SVM, the relationship between Zero Vectors and Zero Sequence is studied. Then, with choosing special Zero Sequences, the modulation matrix of two SVM strategies are testified equal to Venturini's and Optimized Venturini's method, so this two Venturini method are one special type of switching sequences of SVM method. At last, the INST method algorithm are derived from SVM method so that it is also a special type of SVM method(SVM-1-2).Differences between these modulation strategies are studied from input current harmonic, output current harmonic and Common-Mode Voltage(CMV). Theory analysis and Simulation results show that SVM-2-13, SVM-3 and SVM-AV have better performance on input and output current, SVM-2-13, SVM-1-1 and SVM-1-3 have small CMV magnitude and RMS value.At last, experiment results shows that when load inductance is small, high frequency harmonics play an important role, the comparison result is similar to theory analysis and simulation results. But when load inductance has big value, the low order harmonics are more important, so the output current THD comparison results change. For input current, SVM-2-13 shows lower THD than others'which is accord with theory analysis. SVM-1-1, SVM-1-3 and SVM-2-13's CMV experiment result is the same as simulation and theory analysis. In sum, SVM-2-13 and SVM-3 have better performance.