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Journal ArticleDOI

Thyristor converter-fed synchronous motor drive

01 Sep 1981-Electric Machines and Power Systems (Taylor & Francis Group)-Vol. 6, Iss: 5, pp 433-449
TL;DR: In this article, the development, design and construction of a variable speed drive using a synchronous motor is described, and the digital simulation based on simplified block diagram is accurate enough for obtaining the responses of the system to step changes in speed reference and load on motor.
Abstract: The development, design and construction of a variable speed drive using a synchronous motor is described in this paper. At first, the operation of motor with a current-fed, motor e. m. f. commutated inverter is explained. The working of control circuitry is explained next with the aid of logic and functional blocks. The power circuit, comprising the converter, inverter and motor has been reduced to simple blocks so that the controller design by hand computations becomes possible. It has also been shown that the digital simulation based on simplified block diagram is accurate enough for obtaining the responses of the system to step changes in speed reference and load on motor.
Citations
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Journal ArticleDOI
TL;DR: In this paper, the capacitors of the reluctance motor and inverter are connected at machine terminals to obtain a wide range of speed control by varying the d.c. link voltage and value of the terminal capacitors.
Abstract: The naturally commutated d.c. link inverter is employed for feeding the active power to the reluctance motor. The lagging reactive power requirements of the motor and inverter fulfilled by connecting the capacitor bank at machine terminals. A wide range of speed control is obtained by varying the d.c. link voltage and value of the terminal capacitors.
References
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Journal ArticleDOI
TL;DR: In this article, a load-commutated inverter consisting of two bridges connected in parallel is used to provide two-way power flow by reversing the dc current. But the control system described does not use shaft position sensing, but senses the motor terminal voltage and the ac line current to determine the motor internal operating conditions.
Abstract: Synchronous motor drives are beginning to enjoy renewed popularity for certain applications such as flywheel energy storage. One of the reasons is that a synchronous motor drive can be made self-commutating so that the inverter becomes equivalent to a conventional phase-control bridge converter without large commutating components. The drive to be controlled consists of an inductor alternator coupled to a flywheel that will be used for temporary energy storage. The flywheel speed will vary over a two-to-one range; thus full performance can be achieved using a load-commutated inverter. A simple auxiliary commutating circuit is provided only for initial starting. The drive must operate both from a fixed dc voltage source (battery) and from a variable dc voltage source (dc motor), as it is intended for use in a battery-powered vehicle for load leveling. The load-Commutated inverter consists of two bridges connected in parallel so as to provide two-way power flow by reversing the dc current. The control system described does not use shaft position sensing, but senses the motor terminal voltage and the ac line current to determine the motor Nare internal operating conditions. This control method maintains the silicon-controlled rectifier (SCR) turn-off time as a constant percentage of the period of the generated back electromotive force (EMF) as speed and current are varied during operation. The inverter turn-off time is thus maintained by feedback control rather than the use of special function generators. A 20-kVA laboratory development drive system has been built and successfully tested using this control strategy.

58 citations

BookDOI
01 Jan 1970

47 citations

Journal ArticleDOI
TL;DR: In this article, a load-commutated inverter synchronous motor drive system employing a simple auxiliary commutation circuit for machine startup is analyzed, and results hybrid computer simulation are presented.
Abstract: A load-commutated inverter synchronous motor drive system employing a simple auxiliary commutation circuit for machine startup analyzed, and results hybrid computer simulation are presented. The commutation circuit employs a single commutation capacitor connected to the neutral of the machine and two auxiliary thyristors, which are used only during machine starting. A practical operating scheme is developed for the forced commutated inverter, which insures commutation over all load currents by actively allowing the commutation capacitor to charge to a voltage proportional to load, current. Results of key computer runs are given including inverter waveforms, transient waveforms during transition from forced to load commutation, as well as the effect of forced commutation and load commutation on pulsating torque. The forced-commutation circuit is used only for synchronous machine startup. However, due to its simplicity it also is an attractive alternative to be considered for other types of current-fed inverter ac drives.

45 citations