Fundamental Frequency Switching Strategies of a Seven-Level Hybrid Cascaded H-Bridge Multilevel Inverter

• Published in: IEEE transactions on power electronics Vol. 24; no. 1; pp. 25 - 33
• Main Authors: Zhong Du, Tolbert, L.M., Ozpineci, B., Chiasson, J.N.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.01.2009; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Batteries; Capacitors; Circuit properties; Circuits; Dielectric, amorphous and glass solid devices; Direct current; Electric currents; Electric power; Electric, optical and optoelectronic circuits; Electrical engineering. Electrical power engineering; Electronic circuits; Electronic equipment and fabrication. Passive components, printed wiring boards, connectics; Electronics; Exact sciences and technology; Frequency; Fuel cells; Fundamental frequency modulation control; hybrid cascaded H-bridge multilevel inverter (HCMLI); Inverters; Motor drives; Multilevel; Power capacitors; Power electronics, power supplies; Power sources; Power supplies; Resonant frequency; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Signal convertors; Switching; Thermal stresses; Transformers; triplen harmonic compensation; Voltage; Electric transformer; Power converter; Output power; Conversion rate; Power supply; Fundamental frequency modulation control; Implementation; Switching conditions; Direct current; Power supply quality; Energy quality; Multilevel system; Fuel cell; Fundamental frequency; Inverter; Current source; Motor drives; Secondary cell; Power capacitor; Power electronics; Switching; hybrid cascaded H-bridge multilevel inverter (HCMLI); High power; triplen harmonic compensation; High efficiency; Service quality; Cascade connection
• ISSN: 0885-8993; 1941-0107
• DOI: 10.1109/TPEL.2008.2006678

This paper presents a cascaded H-bridge multilevel inverter that can be implemented using only a single dc power source and capacitors. Standard cascaded multilevel inverters require n dc sources for 2 n + 1 levels. Without requiring transformers, the scheme proposed here allows the use of a single dc power source (e.g., a battery or a fuel cell stack) with the remaining n -1 dc sources being capacitors, which is referred to as hybrid cascaded H-bridge multilevel inverter (HCMLI) in this paper. It is shown that the inverter can simultaneously maintain the dc voltage level of the capacitors and choose a fundamental frequency switching pattern to produce a nearly sinusoidal output. HCMLI using only a single dc source for each phase is promising for high-power motor drive applications as it significantly decreases the number of required dc power supplies, provides high-quality output power due to its high number of output levels, and results in high conversion efficiency and low thermal stress as it uses a fundamental frequency switching scheme. This paper mainly discusses control of seven-level HCMLI with fundamental frequency switching control and how its modulation index range can be extended using triplen harmonic compensation.