Generalised direct positioning approach for multilevel space vector modulation: theory and DSP-implementation

In three-phase DC-AC multilevel converters, the space vector modulation is the preferred pulse width modulation (PWM) technique. A particular area relative to the space vector modulation (SVM) analysis for multilevel converter is focused and a direct positioning approach for finding the location of the reference vector among available triangles within the SVM diagram is proposed. The developed procedure is then generalised for an n-level converter by proposing a (n - 1)² times 1 complex matrix that locates the exact place at the end of the reference vector. To verify the proposed method, the whole modulation process was implemented with DSP for three- and four-level converters. To prove the effectiveness of the proposed method in higher-level cases, it was also applied to five- and six-level SVMs. Experimental results validate the direct positioning approach to be an accurate and reliable technique for digital implementation purposes, reducing the total modulation time as well as saving it for complex control techniques needed in industrial applications of SVM.