Masahiko Tsukakoshi

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A higher efficiency is one of the important features required on large capacity converters. As high voltage and large capacity power semiconductor devices replacing conventional GTO thyristors, 4.5 kV IEGTs (injection enhanced gate transistors) and IGBTs have been placed on the market, for use in inverters for driving large motors of rolling mills, pumps,(More)
This paper provides theoretical, numerical, and experimental comparisons in electrical-drive performance between a double-star chopper-cells (DSCC) inverter and a triple-star bridge-cells (TSBC) converter. The inverter and converter are two of the most promising members of the modular multilevel cascade converter (MMCC) family. Two sets of downscaled(More)
Reduction of energy consumption and CO<inf>2</inf> emissions are recognized as important environmental issues in today's world. In addition, Oil and Gas companies are striving for ways to increase their capacity and maximize system uptime in order to meet the global energy demand. To realize these goals, Oil and Gas utilities are looking for electrical(More)
Continuous improvements in the power rating and switching characteristics of power semiconductor devices have enabled the use of power electronics converters in high power variable speed drives (VSDs). These multimegawatt drives are needed for driving large capacity compressors in liquefied natural gas (LNG) plants. However, the generated harmonics and(More)
This paper makes an intensive comparison in operating performance between a modular multilevel double-star chopper-cells (DSCC) inverter and a modular multilevel triple-star bridge-cells (TSBC) converter. Both inverter and converter are intended to drive medium-voltage motors in industrial applications. First, it makes numerical comparisons, thus, resulting(More)
Reduction of energy consumption and CO2 emissions are recognized as important issues in today’s world. In addition, oil and gas companies are looking for ways to increase their capacity and maximize system uptime in order to meet the global energy demand. To realize these goals, oil and gas facilities are looking for 261 STUDY OF LARGE VSI DRIVE SYSTEM FOR(More)
Oil and gas are the most important energy resources on the globe. They need to be transported to feed the energy to remote cities and towns. For efficient use of energy, variable frequency drives (VFD) are used in domestic and industrial appliances. In Industrial applications such as the gas industry, capacity of driven compressors is extraordinary large(More)
This paper provides a theoretical and experimental discussion on ac-inductors design for a modular multilevel triple-star bridge-cells (TSBC) converter, or shortly a TSBC converter. This converter requires multiple ac inductors for controlling nine cluster currents. This paper proposes three three-legged, six-winding, &#x201C;interzigzag&#x201D; inductors(More)
Electrical drives for large capacity compressors in a liquefied natural gas (LNG) plant have been investigated. There are mainly two topologies for such an electrical drive; load commutated inverters (LCIs) and voltage source inverters (VSIs). Due to commutation of the thyristors, LCIs produce current harmonics with variable frequencies, and their(More)
Electrical drives for large capacity compressors in a liquefied natural gas (LNG) plant have been investigated. There are mainly two topologies for such an electrical drive; load commutated inverters (LCIs) and voltage source inverters (VSIs). Due to commutation of the thyristors, LCIs produce current harmonics with variable frequencies, and their(More)