A Multilevel 30-Sided Space Vector Structure With Congruent Triangles and Timing Calculation Using Only Sampled Reference Voltages

In this article, a multilevel inverter scheme to generate a 30-sided space vector structure (SVS) with congruent triangles is proposed. The 30-sided SVS eliminates all the lower order harmonics till 25th order from motor phase voltage throughout the modulation range. The proposed scheme is implemented using a single dc-link on an open-end induction motor (OEIM). The OEIM is fed with primary inverter from one end and secondary inverter from the other end. Primary inverter is fed from an active dc-link and supplies all the required active power for the scheme. Secondary inverter is a capacitor fed inverter, which acts as the switched capacitive filter. In this work, a simple algorithm is proposed, which calculates the timings required for a 2-level 30-sided SVS from sampled reference voltages. The algorithm requires only simple operations such as addition, multiplication, and comparisons. From the obtained timing values, the space vector location of three nearest multilevel 30-sided vectors and its time duration can be identified. The feasibility of the proposed scheme is proved by experimental results.