In this thesis, the neutral point potential drift/fluctuation of the three-level neutral
point clamped inverter is analyzed and a novel control algorithm, the two-parameter
PWM method is proposed to confine the neutral point potential variation to a very
small range. The two-parameter PWM method provides superior neutral point
potential control performance even with small DC bus capacitors. The method is
based on PWM pulse pattern modification and requires no additional hardware.
Detailed analytical models of the neutral point current and potential as a function of
the modulation parameters are established and the neutral point potential behavior is
thoroughly investigated. Based on the study, the deficiency of the known methods is
illustrated and the two-parameter PWM method is developed and its superior
performance demonstrated. The performance of the two-parameter PWM method is
verified by means of computer simulations utilizing both the per-PWM-cycle
average model and the detailed model of the inverter. The results are supported by
laboratory experiments involving both an R-L load and an induction motor drive.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12606928/index.pdf |
| Date | 01 December 2005 |
| Creators | Ustuntepe, Bulent |
| Contributors | Hava, Ahmet Masum |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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