Title :
A power-equalized harmonic-elimination scheme for utility-connected cascaded H-bridge multilevel converters
Author :
Vassallo, Joseph ; Clare, Jon C. ; Wheeler, Patrick W.
Author_Institution :
Sch. of Electr. & Electron. Eng., Nottingham Univ., UK
Abstract :
Although fundamental frequency switching has been the preferred method for high-power medium-voltage multilevel converters, the technology of current generation power semiconductors has made it possible to use higher rates. In utility-connected applications, where a restricted modulation index range is usually sufficient, a main requirement is for very tight control over individual harmonics. For these reasons, this paper considers the application of selective harmonic elimination PWM (SHEPWM) with 5- or 7-level converters switching at low multiples of the fundamental frequency. An alternative approach for the calculation of multiple solutions of the firing angles is outlined, and is then applied in a modulation scheme that inherently equalizes the power flow from and to the individual DC energy sources. Results from computer simulations for a 7-level energy conversion system are presented in this paper.
Keywords :
PWM power convertors; harmonics suppression; power control; power conversion harmonics; power engineering computing; switching convertors; 7-level energy conversion system; firing angles; medium voltage power converters; modulation index range; power equalization; power equalized harmonic elimination method; power semiconductors; pulse width modulation; selective harmonic elimination PWM; utility grid; utility-connected cascaded H-bridge multilevel converters; Computer simulation; Energy conversion; Frequency conversion; Load flow; Medium voltage; Power generation; Power semiconductor switches; Pulse width modulation; Pulse width modulation converters; Switching converters;
Conference_Titel :
Industrial Electronics Society, 2003. IECON '03. The 29th Annual Conference of the IEEE
Print_ISBN :
0-7803-7906-3
DOI :
10.1109/IECON.2003.1280221