The research work proposes an inverter topology for the first time for suppression of all lower order harmonics (5th, 7th, 11th, 13th, etc.) up to 39th harmonic. The lower order harmonic suppression is achieved by switching the 42-sided polygonal vectors, which eliminates harmonics in phase voltage. The power circuit topology uses a single dc-link supply for the primary inverter. The secondary inverter is fed with a capacitive supply. A novel topology is proposed for the dense six-level secondary inverter. The lower order harmonics in phase voltage are suppressed using the secondary inverter, which acts like a switched-capacitive filter. The voltages of secondary inverter capacitors are balanced using the power balance relationship between the primary inverter and the motor load. The work overcomes limitations of conventional methods of harmonic suppression like Selective Harmonic Elimination which limits the range of linear modulation and increases computational complexity. Employing LC filters for harmonic suppression results in expensive and bulky systems.
R. Dewani, R. R, K. Gopakumar, U. Loganathan, D. Zielinski, and L. G. Franquelo, “Suppression of lower order harmonics for the full modulation range for a two-level inverter-fed IM drive with a switched capacitive filter technique forming a 42-sided voltage space vector structure,” IEEE Transactions on Industrial Electronics, vol. 68, no. 8, pp. 6701–6709, 2021.
R. R, M. Ghosh Majumder, R. Dewani, K. Gopakumar, U. Loganathan, W. Jarzyna, and L. G. Franquelo, “A very high resolution 30-sided space vector generation from a single dc-link for induction motor drives,” IEEE Transactions on Industrial Electronics, 2021.