On re-examining symmetry of two-level selective harmonic elimination PWM: Novel formulations, solutions and performance evaluation

• Published in: Electric power systems research 2014-03, Vol.108, p.185-197
• Main Authors: Konstantinou, G., Agelidis, V.G.
• Format: Article
• Language: English
• Subjects: Applied sciences; Convertors; Electrical engineering. Electrical power engineering; Electrical machines; Exact sciences and technology; Half-wave symmetrical PWM; Power electronics; Power electronics, power supplies; Pulse-width modulation; Selective harmonic elimination; Two-level converter
• ISSN: 0378-7796; 1873-2046
• DOI: 10.1016/j.epsr.2013.11.010

•New formulations for selective harmonic elimination pulse-width modulation (SHE-PWM) based on half-wave symmetries are proposed.•By relaxing the symmetry restrictions in two-level SHE-PWM waveforms, the number of solutions that are acquired is significantly extended.•A detailed evaluation of the harmonic performance of the solutions is presented.•Solutions based on HW symmetries can improve the operation of SHE-PWM operated two-level converters. This paper analyzes the half-wave symmetrical two-level SHE-PWM, proposes two formulations of the SHE-PWM waveform with multiple solutions and evaluates the solutions for different cases of eliminated harmonics. Previous work on SHE-PWM focused on algorithms for calculating the solutions and only considered the quarter-wave symmetry in the formulation. In this paper two different formulations to the problem are considered and solutions for a number of eliminated harmonics are presented. The different formulations increase the solution space of the problem and the number of acquired solutions. A comparison of the solutions in terms of harmonic performance is also presented. When compared with the quarter-wave symmetrical solutions, certain half-wave symmetrical solutions exhibit better performance and additional benefits can be acquired for two-level converters operated under SHE-PWM techniques. The HW symmetrical solutions are experimentally verified on a laboratory setup in order to confirm the validity of the solutions sets.