New Simplified and Generalized Three-Dimensional Space Vector Modulation Algorithm for Multilevel Four-Leg Diode Clamped Converter

This article aims to propose a new simplified and generalized three-dimensional space vector modulation (3DSVM) for four-leg multilevel diode clamped converter (FL-DCC). The idea is to use the three-dimensional space vector diagram of the multilevel FL-DCC in alpha beta gamma space, while all calculation stages of the 3DSVM algorithm will be carried out in a new frame called rho sigma tau. The proposed 3DSVM algorithm provides, for any inverter level, 1) simple way to calculate the duration time; 2) automatic generation of the adjacent switching states; 3) balancing the dc capacitor voltages, and 4) switching sequence definition without prism and tetrahedron identification stage. All 3DSVM steps are implemented in only one sector, thanks to the proposed new reference voltage vector. Such feature makes possible to build a generalized 3DSVM that can be implemented with minimum computational burden in simple embedded digital platforms. Simulation and experimental results are provided to demonstrate the proposed concept.