FUJI ELECTRIC JOURNAL Vol.64-No.10 (Oct/1991)
Variable-Speed Drives and Control Technology
Present Status and Prospects for Variable-Speed AC Drives
Takayoshi Nakano, Shigeaki Hori
This paper describes the technical trends of large and medium capacity variable-speed AC drives. It gives an outline of (1) large-capacity PWM inverters and 3-level inverters that utilize high-voltage, high-frequency reverse conducting GTO resulted from the recent development of semiconductor power devices, (2) low-speed, large-capacity cycloconverters, (3) the features of various control systems and digitalized, advanced control, and (4) data transmission networks to the upper-located programmable control-ler of a plant system.
High-Performance GTO PWM Inverters
Makoto Hashii, Kenji Kousaka, Fukashi Uehara
Fuji Electric started to manufacture vector control GTO PWM inverters using large-capacity reverse conducting GTO thyristor (2,500 V/2,000 A) to be used for variable-speed drive systems for plants. The capacity of an inverter is 650 kVA, and a maximum of 1,950 kVA system can be constructed by combining inverters with a polyphase motor. The control system consists of the CPL (Control Oriented Programming Language) DDC system featuring both hardware and software of easy and flexible application. A series of new GTO inverters with high-frequency reverse conducting GTO is a vailable up to 4,500 kVA. The series is planned to be expanded up to 9,000 kVA.
DC Link Transistor Inverters
Arata Sakuma, Kaoru Takahashi, Takafumi Kawai
Fuji Electric has developed industrial DC link transistor invertrers using total DDC (FRENIC4000 series). This paper describes the series classified by applications: (1) FRENIC4000VM3 that adopts vector control to realize precise speed and torque control, (2) FRENIC4000FM with an AVR to control V/f at a constant to drive motors at a time as in conveyor rollers, (3) FRENIC4000T3 used exclusively for the sythetic fiber industry that adopts magnetic flux control. It also outlines a loader developed as a man-machine interface for these drives.
Variable-Speed AC Drive for Industrial Use
Yoshinobu Nagao, Kazunori Hirotsu, Satoru Ozaki
FRENIC5000VG has fully been improved into its successor FRENIC5000VG3. As the result, the new model realizes a vector control inverter easy to use having high performance, multifunction, small size, and improved man-machine interface. To meet market needs for equipment and factory automation, it is provided with a function to communicate with a programmable controller and RAS functions against faults so that it can operate well enough in a processing line and other systems.
Cycloconverter Drive Systems
Masayoshi Chiashi, Hiroshi Osawa, Kazuya Endo
Inverters with self-turn-off device transistors are used widely for variable-speed AC drive, while cycloconverters are used for low-speed large-capacity drive. Among cycloconverter drive systems, circulating current-free cycloconverter fed cynchronous motor drive is superior in respect of input power factor and equipment capacity, induction motor drive is superior in respect of maintenance, and circulating current cycloconverter fed motor drive, controllability. Fuji Electric has completed preparation for the production of all them and is ready to supply the optimum system to meet needs. A GTO cycloconverter that can regulate input power factor at 1 is under development.
Application of Variable-Speed AC Drive to Steel Plants
Tsuneo Kurachi, Hidenori Minami, Tetsuzou Azuma
To meet market needs for rationalization toward 21st century, iron and steel manufacturing plants have been introducing the variable-speed AC drive and control system that integrates power electronics and microelectronics. The drive system improves reliability and control accuracy by sharing functions among the drive, programmable controller, and CRT for operation and supervision; also, it rationalize maintenance and improves the quality of plant system engineering and software.
Application of Variable-Speed AC Drive in Paper Plants
Paper plants have been introducing variable-speed AC drive as a measure to save labor by eliminating brushes and to install motors in an inferior environment. Today, the combination of induction motors and DDC vector control transistor inverters is the mainstream of drive systems.
The paper describes the features of paper machines, coaters, supercalenders, and rewinders, and introduces the latest driving systems for each of them.
Application of Variable-Speed AC Drive to Synthetic Fiber and Film Plants
Masahiro Kina, Masanori Hirano
The use of transistor inverters has been the mainstream of electrical drive systems in synthetic fiber and film plants. Synthetic fiber plants intend to equip with variable-speed AC drives of exclusive use, while film plants, with those of advanced function and general use. Typical examples are a combination of an inverter FRENIC4000T3 and a permosyn motor (permanent magnet synchronous motor) for a spinning machine, and a combination of an inverter FRENIC5000VG3 and a squirrel-cage induction motor for film plants.
Application of Variable-Speed Drive to Chemical Industry
Variable-speed AC drives in chemical plants operate squirrelcage induction motors and thyristor motors. These motors are explosionproof in principle because they have no brushes that cause commutating spark. Many variable-speed AC drives, therefore, are used by chemical industry taking the advantage of being suitable for explosionproof construction in addition to their power-saving effect. Further, recent remarkable progress in hardware and control technology has satisfied needs of variable-speed AC drives for total digital control, of which the paper gives a brief description.
Application of Variable-Speed AC Drive to Machines
Kazunori Hirotsu, Hideaki Nagahama
Starting from use for air and water handing machines aiming at energy saving, variable-speed AC drive has been expanding its application rapidly.This paper describes come of its noticeableapplications: Linear motor drive for traversing the table of a test bench, the traverser and lifting device of a three-dimensional parking garage, the pump drive of a snowmaking machine for a skiing ground, a mass damper for large structures, and the blower drive of a wind tunnel.
Application of Variable-Speed AC Drive to Water Treatment Plants
Water treatment plants require energy saving, optimumsized ponds, a minimized number of pumps, leak prevention, and optimum pressure supply. Variable-speed AC drive was mainly used for driving pumps and blowers to realize precise control that was not possible with constant-speed drive. Recent needs for further reliability and environmental coordination have spread the application of variable-speed AC drive over other loads than pumps and blowers. This paper describes the features of application in water treatment plants and an example of expanded applications.
Support System for Variable-Speed AC Drive
Hidefumi Anno, Kazushi Fujii, Yasuji Nakai
The maintenance and management of plant reliability has become complicated with the increase of the complexity and scale of plants. Now desired are advanced functions to monitor the condition of variable-speed drives and systems in plants and support systems to facilitate the grasp of a fault phenomenon and the pursuit of its cause.
This paper describes a concentrated monitoring system for variable-speed drive, FORS, and a DDC loader, LOAD MASTER, as an example.
Application of Modern Control Theory to Variable-Speed Drive
Akihiko Tanisaka, Koji Yano, Hidetoshi Umida
Plants that uses variable-speed drive systems such as industrial plants always hope for improvement in product quality and high value added. To meet these needs, Fuji Electric put control systems based on modern control theory to practical use earlier than others and has obtained remarkable results in a bar mill plant and so forth.
The paper describes control theory and its applications to actual plants in connection with variable-speed control systems till now, and refers to our attitude toward future.
AI Application to Fault Diagnosis of Variable-Speed Drives
Yuji Todaka, Masashi Kawano
As the digitalization of variable-speed drive made rapid progress, expert systems that introduced knowledge engineering have become able to meet recent needs for improved RAS functions, particularly complete fault diagnosis. Since the expert system COMEX used for fault diagnosis is of a problem-oriented selection and general-purpose type, it has the advantage of up-dating or adding a knowledge base easily on a personal computer without AI expert skill. This paper describes the contents of its fault diagnoses with examples.
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