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A Multimode Space Vector Overmodulation Strategy for Ultrasparse Matrix Converter With Improved Fundamental Voltage Transfer Ratio

In order to increase fundamental voltage transfer ratio for ultrasparse matrix converter, a novel multimode space vector overmodulation strategy is proposed. First, the relationship among voltage transfer ratio (VTR), the output voltage harmonic distortion rate under three inverter modulation methods and the input current harmonic distortion rate under two rectifier modulation methods is analyzed. After that, according to minimum principle of output voltage and input current harmonics, the three overmodulation modes are divided: the output voltage minimum-phase-error, input current minimum-magnitude-error (MME), and output voltage MME overmodulation strategies are realized in overmodulation mode I, II, and III, respectively. The proposed multimode overmodulation strategy not only extends the maximum VTR to 1.05, but also reduces the output low-frequency harmonic voltage components of the overmodulation mode I and mode II. In addition, the harmonic components of output voltage and input current in overmodulation mode are analyzed by double Fourier integral transform method. Finally, the effectiveness of the proposed multimode overmodulation strategy and the correctness of harmonic analysis method are verified by experiments.