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Journal ArticleDOI

Steady state analysis of an inverter-fed induction motor employing natural commutation

01 Jan 1990-IEEE Transactions on Power Electronics (IEEE)-Vol. 5, Iss: 1, pp 117-123
TL;DR: In this article, a steady-state analysis of a three-phase induction motor fed by a DC link inverter commutated by machine-induced EMF is presented, where the active power requirement of the motor is met by the DC link, and the necessary reactive power is supplied by a capacitor bank connected at the motor terminals.
Abstract: A steady-state analysis of a three-phase induction motor fed by a DC link inverter commutated by machine-induced EMF (electromotive force) is presented. The active power requirement of the motor is met by the DC link, and the necessary reactive power is supplied by a capacitor bank connected at the motor terminals. A generalized analytical model is developed for no-load as well as loaded conditions of the motor. The steady-state performance of the motor is numerically evaluated. The computed results are compared with corresponding experimental results for a 4 HP squirrel cage induction motor. The relevant oscillograms of voltage and current waveforms of the inverter and motor are presented and discussed. >
Citations
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Journal ArticleDOI
12 Oct 2003
TL;DR: In this paper, a hybrid solution employing a combination of a load-commutated inverter and a voltage-source inverter is proposed for the induction motor drives by avoiding the use of output capacitors and a forced DC-commutation circuit.
Abstract: A novel, hybrid solution employing a combination of a load-commutated inverter and a voltage-source inverter is proposed for the induction motor drives. By avoiding the use of output capacitors and a forced DC-commutation circuit, this solution can eliminate all disadvantages related with these circuits in the conventional load commutated inverter based induction motor drives. In addition, improved quality of output current waveforms and faster dynamic response can be achieved. The proposed hybrid scheme features the following tasks: (1) the safe commutation angle for the load commutated inverter, controlled by the voltage source inverter in all speed region of the induction motor and (2) a DC-link current control loop to ensure minimum voltage source inverter rating. Advantages of the proposed solution over the conventional load commutated inverter based induction motor include the followings: (1) sinusoidal motor phase current and voltage based on the instantaneous motor speed control; (2) fast dynamic response by the voltage source inverter operation; (3) elimination of motor circuit resonance and motor torque pulsation. The feasibility of the proposed hybrid circuit for the high power drive system is verified by computer simulation for a 500 hp induction motor. Experimental results are also under way in our laboratory to show the validity of the proposed technique.

49 citations

Journal ArticleDOI
TL;DR: The feasibility of the proposed hybrid circuit for the high-power drive systems is verified by computer simulation for a 500-hp induction motor, and experimental results are also included for a 1- hp induction motor laboratory setup controlled by the proposed Hybrid system.
Abstract: A hybrid converter system employing a combination of a load-commutated inverter (LCI), a dc-dc buck converter, and a voltage-source inverter (VSI) is proposed for the large induction motor drives. The VSI ensures the safe commutation of the LCI with active commutation angle control over all speed regions. By replacing capacitor banks and a forced dc-commutation circuit, this system can eliminate all drawbacks related to these circuits in the conventional LCI-based induction motor drives. Sinusoidal motor current and voltage waveforms are achieved with the VSI providing the reactive and harmonic power to the motor, resulting in high-performance drives. The buck converter enables both the VSI and the LCI to be fed from the single-diode rectifier. As a result, the dc-link inductor size can be reduced and the LCI is operated without the controlled rectifier. In addition, faster dynamic response can be obtained through the VSI and the buck converter operation. Finally, the buck converter performs the dc-link current control to ensure minimum VSI rating. The feasibility of the proposed hybrid circuit for the high-power drive systems is verified by computer simulation for a 500-hp induction motor. Experimental results are also included for a 1-hp induction motor laboratory setup controlled by the proposed hybrid system.

39 citations

Journal ArticleDOI
TL;DR: In this article, a load-commutated current source inverter (LCCSI) induction motor drive system employing a novel DC-side forced commutation circuit for machine start-up is proposed.
Abstract: A load-commutated current source inverter (LCCSI) induction motor drive system employing a novel DC-side forced commutation circuit for machine start-up is proposed. To avoid the adverse effects of harmonic resonance between the output capacitor and the inductance of the induction motor, a solution is proposed using a special type of one-notch current PWM, fully utilizing the proposed commutation circuit. A direct vector controller, which refers to the fixed reference frame of the rotor flux without using a speed sensor, is applied. In addition to compensating for the capacitive current, this controller is applied to decouple the torque and flux generating currents and to overcome the instability caused by the output capacitor. The feasibility of the proposed circuit for the high power drive system is verified by computer simulation for a 600 hp induction motor. Experimental results for a laboratory LCCSI-induction motor (10 hp) are also included. >

31 citations

Proceedings ArticleDOI
10 Mar 1991
TL;DR: In this paper, the steady state characteristics of an induction motor drive system employing a load commutated current source inverter (LCCSI) were investigated using a linearised model.
Abstract: The authors present a systematic study of an induction motor drive system employing a load commutated current source inverter (LCCSI). The steady-state characteristics of a LCCSI-fed induction motor are shown to be the intermediate characteristics between the voltage source inverter (VSI) and the auto sequentially commutated current source inverter (ASCI). The dynamic characteristics of the LCCSI-fed induction motor are investigated using a linearised model. A study through the pole/zero locations of the linearized system shows that a V/Hz ratio control loop plays an essential role in the stabilization of the system. >

10 citations


Cites background from "Steady state analysis of an inverte..."

  • ...This type of CSI has been called a load commutated CSI (LCCSI).[3, 4 ]...

    [...]

Proceedings ArticleDOI
27 Sep 2004
TL;DR: In this paper, a hybrid converter system employing combination of a load-commutated inverter (LCI), a DC-DC buck converter, and a voltage-source inverter is proposed for the large induction motor drives.
Abstract: A novel, hybrid converter system employing combination of a load-commutated inverter (LCI), a DC-DC buck converter, and a voltage-source inverter is proposed for the large induction motor drives. By avoiding the use of output capacitors and a forced decommutation circuit, this system can eliminate all disadvantages related to these circuits in the conventional LCI based induction motor drives. Improved quality of output current waveforms and faster dynamic response can be achieved. In addition, the use of the buck converter enables reduction of the delink inductor size and eliminating requirement for the controlled rectifier. The proposed hybrid scheme features the following tasks: 1) safe commutation angle for the LCI controlled by the voltage source inverter over all speed regions, and 2) a delink current control loop to ensure minimum voltage source inverter rating. Advantages of the proposed solution over the conventional LCI-based induction motor include the followings: 1) sinusoidal motor phase current and voltage based en the instantaneous motor speed control; 2) fast dynamic response through the operation of voltage source inverter and buck converter; 3) elimination of motor circuit resonance and motor torque pulsation; 4) compact and simple system implementation due to small size of the delink inductor. The feasibility of the proposed hybrid circuit for the high power drive system is verified by computer simulation for a 500 hp induction motor. Experimental results to support the use of the proposed system are also included for a 1 hp induction motor laboratory setup.

10 citations

References
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Book
01 Jan 1982

306 citations

Journal ArticleDOI
Bimal K. Bose1
01 Feb 1982
TL;DR: In this paper, the authors reviewed the present status of ac drives technology in which the salient technical features of ac machines, converters, controls, and performances of the integrated drive systems have been discussed, and the appropriate trend of the technology has been indicated.
Abstract: The technology of solid-state adjustable speed ac drives was launched in the 1960's. Since then many innovations in devices, circuits, control theory, and signal electronics have made a considerable contribution to this technology. With the heritage of past experience, and the projection of present trends, an almost certain prediction can be made that adjustable speed ac drives will find widespread applications in industry before the end of this decade. The paper reviews the present status of ac drives technology in which the salient technical features of ac machines, converters, controls, and performances of the integrated drive systems have been discussed, and wherever possible, the appropriate trend of the technology has been indicated.

103 citations

Book
19 Nov 1984
TL;DR: In this article, the authors introduce the underlying principles of operation of power semiconductor drives and explain every facet of application of power electronics to the control of electric motors in industrial drives.
Abstract: This textbook introduces students to the underlying principles of operation of power semiconductor drives. It explains every facet of application of power electronics to the control of electric motors in industrial drives. The book is primarily intended for B.E./B.Tech. students of Electrical Engineering/ Electrical and Electronics Engineering having courses in Electric Drives/ Power Semiconductor Drives. It will also be highly useful for M.E./M.Tech. students of these disciplines specializing in Power Electronics/Industrial Drives/Electric Drives. The text is divided into eight chapters. The first two chapters cover the control of dc motors by using various kinds of converters. The third chapter focuses on dual converters and various braking techniques. Chopper control fed dc motors are discussed in the fourth chapter. The next three chapters are devoted to control methods for induction motors. The eighth chapter deals with the control of synchronous motor drives fed from VSI converters and cycloconverters. Extensively illustrated, the book contains numerous solved examples throughout the text as well as a variety of chapterend questions to help in comprehending as well as in strengthening the grasp of the underlying concepts and principles. (Goodreads)

74 citations

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

Journal ArticleDOI
TL;DR: In this article, the transient performance of self-controlled synchronous motors which are used as variable speed motors in industries is analyzed considering two types of position sensor used in these motors.
Abstract: The transient performance of self-controlled synchronous motors which are used as variable speed motors in industries is analyzed considering two types of position sensor used in these motors. A set of equations valid for the transient state is first derived and represented in a block diagram. Based on these equations, mechanical and electrical transient responses of the motors in the case of a step change in input voltage are analyzed. It is shown that the transient responses differ remarkably depending on the type of position sensor used. The transient characteristics of margin angle of commutation of thyristors are then compared in detail with the steady-state ones. It is shown that the thyristors in the inverter are commutated more successfully in the transient state than in the steady state when compared at the same dc input current. Finally, the transient responses in the case of a step change in load torque are investigated.

47 citations