Power Electronics for Industrial Applications

An Overview of Recent High-Power Conversion Systems
Ginjiro Yanai
This paper describes recent technology and trends in future of high-power conversion systems. With the development of power semiconductor devices and the advance in functions of controllers, high-power conversion systems have greatly contributed to the improvement of productivity in the fields of industry and the electric railway, as well as to better environments such as improvement in power line quality and reduction in acounstic noise. Electric power has been and will be the mainstream of energy sources because of its cleanness, and the flexibility of high-power conversion systems will be required more and more.

Core Technologies of Power Electronics for Industrial Applications
Naoya Eguchi, Kiyoshi Takahashi, Kouji Maruyama
The conversion system used in power systems, industrial equipment, and electric railways is the technology of converting and controlling vast power using electronics. This paper describes the requirements of power conversion systems applied in these fields. Further, it outlines the present status and future prospects for basic technologies that support high-power electronics: (1) devices and circuitry technology (2) high power stacking technology (3) control technology (4) converter and system analysis technology.

Chopper System for Ash Melting Equipment
Katsuya Uto, Koji Hino, Haruhiko Shinonaga
The ash melting equipment melts and solidifies burned and fly ashes from incinerators. It is a measure for prolonging the life of final disposal lands for general waste. It is becoming of still more importance to living environment preservation. Formerly, the thyristor rectifier was used for the power supply of plasma-arc ash melting. Recently, Fuji Electric has developed a chopper type power supply using the IGBT. This paper describes the merits of the chopper type power supply, key points in system design, and the chopper circuit.

Power Conversion System for Electric Power Storage with Secondary Batteries
Kazunari Komatsugi, Masanobu Fujikura
The electric power storage system with secondary batteries is useful for load leveling of a power system. This system, using DC power, requires a power conversion system to connect with the commercial AC line. The power conversion system can be used not only for electric power storage for load leveling but also for raising power quality such as improvement in power factor and compensation for supply voltage dip or interruption of supply voltage. This paper outlines the basic configuration of the power conversion system, the system construction and features of effective functions, examples of supplied units and operating waveforms, and charging/discharging simulation technology.

Static Frequency Converters for Generator/Motor Starters
Kenji Okuma, Kinya Moriyama, Hiroshi Shinohara
Generator/Motor starters utilizing power electronics are equipped in pumped storage power stations. The pumped storage power station is generally under the ground and the equipment has to be small to reduce civil cost. To meet this requirement, the application of high voltage to starters has been developed. Besides, the pumped storage power station, large in capacity and important in the power system, requires high reliability. This paper introduces new technologies adopted in the starters and control systems manufactured for the pumped storage power station for export to India.

Var Compensators
Shigeo Konishi, Kenji Baba, Mitsuru Daiguji
The static var compensator (SVC) utilizing power electronics has widely been used in power systems to suppress voltage fluctuation and flickering. Further, the progress of large capacity self-extinguished devices such as the GTO and IGBT has advanced the application of the self-commutated SVC. This paper describes the technical trend and converter technology of the self-commutated SVC using a flat IGBT, which can give higher performance and smaller size than the GTO type, and recent examples of SVC applications.

Transformer-Rectifier Package (S-Former) for Aluminum Smelting
Shinichi Furuki, Ginji Ishizuka
Fuji Electric has supplied 74 rectifiers for aluminum smelting and now keeps a top-class share in the world. To reduce production cost, the aluminum smelting industry raised equipment voltage and current by increasing the number of smelter cells in series and current carrying area per unit cell. To meet these needs, We raised the S-former rating by technical development, and in 2000, supplied S-formers with the largest unit capacity in the world. This paper describes ingenious designs for the circuitry of this compound unit consisting of a transformer and a rectifier, the development of the rectifying semiconductor device, and application technology for the high-power device and fuse.

Custom-Waveform Power Supply for Metal Surface Treatment
Tetsuhiro Maruo
In the specific treatment of metal surfaces such as color anodizing on aluminum sashes and electroplating on substrates, electrolytic treatment with a special waveform is effective for foil uniformity, the yield rate, and compatibility with multiple colors and advanced-function foils. This paper describes the following application examples of custom-waveform power supply for metal surface treatment: the large capacity unit for color anodizing on aluminum sashes (50V, 10kA, delivered to Toyama Light Metal Industry Co., Ltd.) and the result of experiment with the unit for copper plating on substrates.

Thyristor Inverters for Induction Heating and Recent Applications
Iwao Kurata, Kiyokazu Nakamura
Thyristor inverters are most advantageous power supply for large capacity and low frequency applications. This paper describes the fea-tures and specifications of thyristor inverters for induction heating and their recent application examples, including a 13,000kW, 300Hz inverter for an induction furnace and a 1,000kW, 10kHz inverter for thin plate annealing. In addition, a newly developed controller for thyristor inverters is referred to.

MOSFET Inverter Type High-Frequency Power Supply
Toshie Miura, Kiyokazu Nakamura
Fuji Electric has newly developed a large-power, flat-package, 500V, 500A MOSFET and a 125kW stack with the MOSFET. These have been applied to 1,000kW, 150kHz high-frequency power supply. Thenew device has the same dimensions as conventional one, but its rated current has doubled or more. Though the volume and mass of the new stack become to 80% and 60% respectively, its output power has increased by 25% as compared with conventional one. This paper describes the features and test results of these products, and so on. Also it introduces recent power supply for seam welding and application of high-frequency power supply,for example plasma heating.

Vaporization-Cooling Silicon Rectifiers for Railway Substations
Shingo Tsuda, Toyotada Nakamura, Shuji Odaki
The silicon rectifier, a main piece of equipment in electric railway substations, has so far used a vaporization cooling system using perfluorocarbon (PFC) for the refrigerant. However, PFC was designated as a global warming substance in the Kyoto Conference on Global Warming (COP3) in 1997 and its use will be controlled in the future. Fuji Electric developed an epoch-making vaporization-cooling silicon rectifier that uses pure water intrinsically harmless to the environment for the refrigerant and has still more merits, and started sale. This paper describes the history of silicon rectifiers and the new silicon rectifier.

New Frequency Changer for the Running Test of the Shinkansen Cars
Kenji Baba, Kazuyoshi Umezawa, Yasushi Motoki
A car manufacturer requires a car testing power supply system capable of outputting 50/60Hz for AC trains. The power supply for testing the Shinkansen cars in the Hyogo Factory of Kawasaki Heavy Industries, Ltd. had been used for 20 years since delivered and became necessity for improvement from the viewpoint of capacity and functions. Under the circumstances, Fuji Electric developed and delivered a self-commutated frequency changer using IGBT devices instead of the self-commutated thyristor system. This paper describes the configuration of the supplied system and the result of evaluation on the actual running performance.


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