A 21-level (line-to-line) BTB system based on series connection of 16 converter cells. Experimental verification by a 200-V, 20-kW laboratory system.

A 21-level (line-to-line) self-commutated BTB (Back-To-Back) system based on series connection of 16 converter cells has attractive features as follows: (i) Both active and reactive powers can be controlled independently even in transient states. (ii) The BTB system produces almost sinusoidal voltage at the AC side without performing PWM (Pulse-Width-Modulation) control, so that no harmonic filter is required. (iii) The BTB system provides an active power reason as high as 3 ms. This paper presents experimental verifications of the self-commutated BTB system intended for achieving power flow control in transmission systems. Experimental results obtained by a 200-V, 20-kW laboratory prototype confirm effectiveness and validity of both the system configuration and the developed control strategy. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(1): 61– 70, 2007; Published online in Wiley InterScience (<URL>www.interscience.wiley.com</URL>). DOI 10.1002/eej.20324 [ABSTRACT FROM AUTHOR]