717 publications from this institution
The emergence of high-power semiconductor devices such as insulated-gate bipolar transistors (IGBTs) or injection-enhanced gate transistors (IEGTs) and gate-commutated turn-off (GCT) thyristors or integrated gate-commutated thyristors (IGCTs) enables large static converters to expand into utility and industry applications. For instance, a /spl plusmn/80 kV 50 MW HVDC transmission system based on a string of many IGBTs connected in series was commissioned in 1999. This paper describes the present status of large static converters, with focus on their applications to utility and industry. The applications discussed are: HVDC transmission system, UPFC, flywheel energy storage system, pumped hydro plant adjustable speed generator, active filters for power conditioning, and steel mill drives. The paper also describes their future prospects and directions in the 21st century, including the personal views and expectations of the author.
Renewable energy sources such as wind turbine generators and photovoltaics are intermittent in nature, thus resulting in fluctuating electric power. Leveling of their electric power is indispensable to realize large‐scale renewable energy sources and to avoid severe power quality problems when they are interconnected into the grid. A battery energy storage system (BESS), combining batteries with a power converter and digital control, should be installed in the vicinity of an intermittent energy source. The fluctuating power is compensated by appropriately controlling active power stored in, or released from, the battery. This paper describes a 6.6‐kV transformerless battery energy storage system based on a cascade multilevel PWM (pulse‐width‐modulation) converter, with focus on a control method for active power and SOC (state‐of‐charge) balancing. A down‐scaled 200‐V, 10‐kW, 3.6‐kWh (13‐MJ) laboratory model using nine NiMH (Nickel Metal Hydride) battery packs was designed, constructed, and tested to verify the viability and effectiveness of the 6.6‐kV system. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 177(1): 43–54, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21127
