Application of a modular multilevel cascade converter (MMCC-SDBC) to a STATCOM. Control of active power and negative-sequence reactive power.

This paper presents the application of a modular multilevel cascade converter based on single-delta bridge-cells (MMCC-SDBC) to a STATic synchronous COMpensator (STATCOM), particularly for negative-sequence reactive-power control. The SDBC is characterized by cascade connection of multiple single-phase H-bridge (or full-bridge) converter cells per leg, which facilitates flexible circuit design, low voltage steps, and low electromagnetic interference (EMI) emissions. However, there is no published report on such a STATCOM with experimental verification or a control strategy. This paper designs, constructs, and tests a 100-V 5-kVA PWM STATCOM based on the SDBC with focus on the operating principle and performance. Experimental results confirm that this converter can control not only the positive-sequence reactive power but also the negative-sequence reactive power and low-frequency active power intended for the flicker compensation of arc furnaces. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 183(4): 33-44, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22365 [ABSTRACT FROM AUTHOR]