EPE Association: EPE 1991 - 24 - Session 3.2: ADVANCED CONTROL STRATEGIES

EPE 1991 - 24 - Session 3.2: ADVANCED CONTROL STRATEGIES
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   LINEARIZED MODEL OF INDUCTION MOTOR DRIVES VIA NONLINEAR STATE FEEDBACK DECOUPLING
By A. Bellini; G. Figalli; F. Tosti [View]
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Abstract: The paper presents a linearized and input-output decoupled model of induction motors obtained through a nonlinear state feedback. This approach has made it possible to carry out a simple model of the motor constituted by two lines of double integrators. In addition, the determination of the components of the motor supply voltage - on the basis of the model inputs and machine state values - does not involve heavy computations. Besides showing the methodology, the paper also analyzes the effects due to variations in the most significant electromagnetic and mechanical parameters and presents the results of some simulations in which a classical PI controller and a tachometer feedback have been adopted as control system. The availability of a simple equivalent model for the induction motor allows the use of more sophisticated control techniques, that the authors are investigating.

   NONLINEAR SPEED CONTROL OF A SYNCHRONOUS SERVOMOTOR WITH ROBUSTNESS
By G. Georgiou; B. Le Pioufle [View]
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Abstract: Nonlinear decoupling and linearization techniques are applied to the control of a synchronous servomotor described by a nonlinear model expressed in the (d,q) frame. Proportional-Derivative controllers associated to the linearized and decoupled closed-loop system, assure asymptotic speed regulation while the direct current id, is maintained to zero. The addition of integrators together with the choice of a rectilinear reference trajectory for the speed, permit to improve the robustness of such a controller without exceeding predetermined constraints on the current iq. Simulation and experimentation results are presented.

   ROBUST SELF-TUNING CONTROL OF AC-SERVO DRIVE
By Michael Tonnes; Henrik Rasmussen [View]
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Abstract: This paper describes a method for robust self-tuning of a speed controlled induction motor drive. Generalized Predictive Control (GPC) is used for the design of the speed regulator. The standard GPC structure is extended to the general RST regulator structure in order to make it comparable to other known design methods. In order to ensure robust control by the RST regulator, a new saturation function is developed for the induction motor drive. The method is tested on a current controlled induction motor drive developed at Danfoss A/S.

   SPEED CONTROL OVER A WIDE OPERATING RANGE OF BRUSHLESS DC MOTOR APPLYING OPTIMAL FEEDBACK CONTROL
By Tsuneo Uchijima; Masahiro Takigawa; Takashige Saijo [View]
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Abstract: An improvement of characteristics for a small size and hand-held type, Brushless DC Motor (BLM) with a permanent magnet rotor, which is controlled in constant speed over a wide rotative speed range, is studied in this paper. The optimal feedback control is applied to the BLM to construct a control system with robustness. A control method adopting variable gain to the compensating element to construct the control system which has excellent transient responses at each reference speed is proposed. To construct the variable compansating gain control, the weight on the optimal feedback control is examined and the relation between the weight and a transient response is clarified. The weight of each reference speed is determined by using their relationship. The optimal feedback gain of each reference speed is calculated from the characteristics of weight versus speed. It is cleared that the analytical and numerical results of the BLM system applying optimal feedback control with variable gain show the characteristics of excellent transient response over a wide operating range. Then, a Digital Signale Processor is using in the experimental circuit. The good characteristics of the BLM system is confirmed by the experiment results.

   TWO DEGREES OF FREEDOM SPEED CONTROLLER USING REFERENCE SYSTEM MODEL FOR MOTOR DRIVES
By Masato Koyama; Masao Yano [View]
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Abstract: This paper proposes a new speed controller based on the two degrees of freedom control method for motor drives. In order to overcome the stability problem caused by the sampling time and dead time of a conventional digital PI speed controller, a reference system model which has a desirable dynamic performance is incorporated. In this system model, the load disturbance is compensated with the disturbance estimater, which estimates the load disturbance from the actual motor speed. By making use of the torque reference generated from the system model, the fast response speed control can be realized. This new speed controller has a great advantage when applied for the motor drives with high inertia load such as paper mills or steel processing lines.

   A VARIABLE-SPEED INDUCTION MOTOR DRIVE USING EXPERT SYSTEM TECHNOLOGY
By J. Douglas Birdwell; Roger D. Horn; Jovan Ilic; Stephen D. Patek; Prathap S. Shanmugam [View]
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Abstract: A new control strategy for induction motors in variable-speed applications using a resonant link inverter is proposed. Standard melhods for generation of the inverter's gate control signals are replaced by an algorithm residing in a floating-point digital signal processor (DSP). The algorithm can be represented as a decision tree, testing measured quantities to produce the binary gate control signals for each phase. The algorithm is automatically generated and coded for the DSP by machine learning software residing in a second processor. An expert system in the second processor monitors the inverter's performance using, for example, measurements of the input current's harmonic content, and can modify theDSP algorithm during on-line operation, adapting inverter operation to changing conditions, and providing initial tuning of the inverter to a specific application.

EPE 1991 - 24 - Session 3.2: ADVANCED CONTROL STRATEGIES
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1991 - Conference > EPE 1991 - 24 - Session 3.2: ADVANCED CONTROL STRATEGIES
	[return to parent folder]

	LINEARIZED MODEL OF INDUCTION MOTOR DRIVES VIA NONLINEAR STATE FEEDBACK DECOUPLING By A. Bellini; G. Figalli; F. Tosti	[View] [Download]
Abstract: The paper presents a linearized and input-output decoupled model of induction motors obtained through a nonlinear state feedback. This approach has made it possible to carry out a simple model of the motor constituted by two lines of double integrators. In addition, the determination of the components of the motor supply voltage - on the basis of the model inputs and machine state values - does not involve heavy computations. Besides showing the methodology, the paper also analyzes the effects due to variations in the most significant electromagnetic and mechanical parameters and presents the results of some simulations in which a classical PI controller and a tachometer feedback have been adopted as control system. The availability of a simple equivalent model for the induction motor allows the use of more sophisticated control techniques, that the authors are investigating.

	NONLINEAR SPEED CONTROL OF A SYNCHRONOUS SERVOMOTOR WITH ROBUSTNESS By G. Georgiou; B. Le Pioufle	[View] [Download]
Abstract: Nonlinear decoupling and linearization techniques are applied to the control of a synchronous servomotor described by a nonlinear model expressed in the (d,q) frame. Proportional-Derivative controllers associated to the linearized and decoupled closed-loop system, assure asymptotic speed regulation while the direct current id, is maintained to zero. The addition of integrators together with the choice of a rectilinear reference trajectory for the speed, permit to improve the robustness of such a controller without exceeding predetermined constraints on the current iq. Simulation and experimentation results are presented.

	ROBUST SELF-TUNING CONTROL OF AC-SERVO DRIVE By Michael Tonnes; Henrik Rasmussen	[View] [Download]
Abstract: This paper describes a method for robust self-tuning of a speed controlled induction motor drive. Generalized Predictive Control (GPC) is used for the design of the speed regulator. The standard GPC structure is extended to the general RST regulator structure in order to make it comparable to other known design methods. In order to ensure robust control by the RST regulator, a new saturation function is developed for the induction motor drive. The method is tested on a current controlled induction motor drive developed at Danfoss A/S.

	SPEED CONTROL OVER A WIDE OPERATING RANGE OF BRUSHLESS DC MOTOR APPLYING OPTIMAL FEEDBACK CONTROL By Tsuneo Uchijima; Masahiro Takigawa; Takashige Saijo	[View] [Download]
Abstract: An improvement of characteristics for a small size and hand-held type, Brushless DC Motor (BLM) with a permanent magnet rotor, which is controlled in constant speed over a wide rotative speed range, is studied in this paper. The optimal feedback control is applied to the BLM to construct a control system with robustness. A control method adopting variable gain to the compensating element to construct the control system which has excellent transient responses at each reference speed is proposed. To construct the variable compansating gain control, the weight on the optimal feedback control is examined and the relation between the weight and a transient response is clarified. The weight of each reference speed is determined by using their relationship. The optimal feedback gain of each reference speed is calculated from the characteristics of weight versus speed. It is cleared that the analytical and numerical results of the BLM system applying optimal feedback control with variable gain show the characteristics of excellent transient response over a wide operating range. Then, a Digital Signale Processor is using in the experimental circuit. The good characteristics of the BLM system is confirmed by the experiment results.

	TWO DEGREES OF FREEDOM SPEED CONTROLLER USING REFERENCE SYSTEM MODEL FOR MOTOR DRIVES By Masato Koyama; Masao Yano	[View] [Download]
Abstract: This paper proposes a new speed controller based on the two degrees of freedom control method for motor drives. In order to overcome the stability problem caused by the sampling time and dead time of a conventional digital PI speed controller, a reference system model which has a desirable dynamic performance is incorporated. In this system model, the load disturbance is compensated with the disturbance estimater, which estimates the load disturbance from the actual motor speed. By making use of the torque reference generated from the system model, the fast response speed control can be realized. This new speed controller has a great advantage when applied for the motor drives with high inertia load such as paper mills or steel processing lines.

	A VARIABLE-SPEED INDUCTION MOTOR DRIVE USING EXPERT SYSTEM TECHNOLOGY By J. Douglas Birdwell; Roger D. Horn; Jovan Ilic; Stephen D. Patek; Prathap S. Shanmugam	[View] [Download]
Abstract: A new control strategy for induction motors in variable-speed applications using a resonant link inverter is proposed. Standard melhods for generation of the inverter's gate control signals are replaced by an algorithm residing in a floating-point digital signal processor (DSP). The algorithm can be represented as a decision tree, testing measured quantities to produce the binary gate control signals for each phase. The algorithm is automatically generated and coded for the DSP by machine learning software residing in a second processor. An expert system in the second processor monitors the inverter's performance using, for example, measurements of the input current's harmonic content, and can modify theDSP algorithm during on-line operation, adapting inverter operation to changing conditions, and providing initial tuning of the inverter to a specific application.