Flexible Third Harmonic Voltage Control of Low Capacitance Cascaded H-Bridge STATCOM

Reliability evaluation and analysis of multi‐terminal interconnect power distribution system with flexible multi‐state switch

“…We assume that each subsystem only has two states (normal and fault), then the FMSS equipment has the following four types of operating modes: (i) the device operates normally; (ii) one of MMCs in three‐port FMSS fails, and the other two MMC ports can operate normally, and in this case, FMSS will switch to a point‐to‐point power supply mode from the original multipoint power supply mode; (iii) two MMC modules fail, in this case, FMSS can still work, but cannot adjust active power and the non‐fault port of FMSS can only control reactive voltage, which is called STATCOM mode [16, 17]; (iv) all three MMC modules fail or the central control system is faulty or the DC side bus and capacitor are faulty, in this case, the entire FMSS is out of service.…”

Evolution of Microgrids with Converter-Interfaced Generations: Challenges and Opportunities

“…In this strategy, two particle swarm optimisation (PSO) algorithms are implemented to obtain the optimal sizing/siting and online control of multiple CPDs. In [40], the operational performance of a low-capacitance cascaded H-bridge STATCOM is optimised to minimise switching losses. Change in network fault level: A distribution network containing DG units is an active network in which the power and extra current can flow in a reverse direction toward the fault side [41], with all types of DG units assisting in increasing the fault level.…”

Harmonic circulation and DC voltage instability mechanism of parallel‐SVG system

“…Regarding DC voltage imbalance of multiple H‐bridge modules, a three‐layer DC voltage control is established in [6] through injecting zero sequence component into the voltage command and adjusting voltage commands of H‐bridge modules of each phase along the direction of the converter current, by which three‐phase active power can be redistributed among each module and DC voltages of modules of each phase can be thus balanced. Ge and Gao [7] present a DC voltage control method for a low‐capacitance cascaded H‐bridge STATCOM, which can adjust the averaged DC voltage according to the compensated reactive power through enlarging the low‐frequency DC voltage ripple, thus keeping DC voltage within the acceptable range. For CHB STATCOM, the adverse effect of switching harmonics on DC voltage, and the DC voltage imbalance in cascaded modules under the different switching frequency are analysed in [8], but the negative impact of the inter‐converter harmonic circulation for multi‐paralleled converters is not addressed.…”