EPE Association: EPE 1985 - 10 - Lecture Session 2.03: CONTROL ALGORITHMS

EPE 1985 - 10 - Lecture Session 2.03: CONTROL ALGORITHMS
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   CASCADE ADAPTIVE SPEED CONTROL OF A THYRISTOR DRIVEN DC-MOTOR
By V. Hahn; H. Unbehauen; R. M. Stephan [View]
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Abstract: A cascade speed control strategy for a thyristor driven DC-motor subjected to parameter variations, is proposed. A dual mode adaptive inner current loop is cascaded with a model reference adaptive speed control loop. The scheme is implemented in a 16-bit microcomputer using a floating point coprocessor. Tests on a DC-machine have been conducted. The proposed solution guarantees a stable and predefined performance under all operating conditions. Comparisons with a conventional analog speed control are made.

   SLIDING MODE CONTROL FOR ROBOTIC MANIPULATOR
By F. Harashima; T. Ueshiba; H. Hashimoto; K. Maruyama [View]
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Abstract: The application of the sliding mode control based on VSS (Variable Structure System) for a multi-joint manipulator is presented. The high-gain effect of sliding mode control suppresses the complicated interactions between the each joints of a robot arm as well as the disturbances due to the parameter variations. The resulting system is completely robust whereas the obtained control law is simple and easy to be applied to on-line computer control. In this paper, the sliding mode controller is implemented to a two-linkage manipulator. The validity of this technique is confirmed in experiments where the system shows the robust performance in spite of the existing nonlinear interactions and unknown parametric changes.

   PARAMETER ADAPTIVE CONTROL OF INDUCTION MOTOR BASED ON STEADY STATE MACHINE MODEL
By K. Harms; W. Leonhard [View]
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Abstract: The induction motor drive described in this paper consists of a voltage source PWM transistor inverter with current control loops producing approximately sinusoidal impressed stator currents in steady state. The amplitude and frequency of the current references are derived from a steady state machine model. In order to obtain good dynamic performance of the speed control loop the references are calculated with the assumption of constant air gap flux. Subsequently this condition is modified with the view of improved efficiency of motor and inverter by varying the air gap flux as a function of the load, causing the lightly loaded motor to operate at reduced flux. The feedback variables are two stator currents and speed which is measured by a digital sensor. All signal processing is performed by a single board microcomputer (CPU 80186) with an analog/digital interface card. As a result, a four quadrant drive with torque limit and good dynamic performance over a wide speed range is obtained, the response time of which is somewhat larger than in case of an optimal field orientated control scheme. However, the computational complexity is considerably reduced. In order to eliminate the effects caused by changing rotor temperature and desaturation in the field weakening region, the varying motor parameters are detected by on-line Fourier transformation of a stator current and a line to line voltage and subsequent updating of the controller parameters. This task is also performed by the microcomputer. The paper covers the underlying theory and demonstrates the design of an experimental 7.5 kW drive.

   INTELLIGENT DIGITAL FIRING CONTROLLER FOR IMPROVING THE POWER FACTOR OF FULLY CONTROLLED BRIDGE CONNECTIONS
By V. Weiss; D. Naunin [View]
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Abstract: An intelligent digital firing controller will be presented, which can reduce the fundamental reactive power of fully controlled bridge connections with simultaneous control of the harmonic content for the line side current by making use of a new control method. The properties of the new control method will be shown. The features of the digital firing controller as well as the hardware realization will be discussed. Results from an electric drive with a converter cascade will be demonstrated.

   ADAPTIVE DIGITAL SPEED AND POSITION CONTROL OF DC-SERVO DRIVES
By R. Schönfeld [View]
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Abstract: Position Drives are almost elastically coupled multimasse-systems with changeable parameters and changeable disturbance signals. In this contribution, simple adaptive structures are discussed, which enables a fast control of the position process undependent upon parameter changes and disturbances. The control is realised by small microcomputers. The state-space-control of the motion-process and adaptive structures using signal-selfadaption are discussed. If the range of parameter-changes is limited, a structure using signal-selfadaption enables a very good dynamic behavior of the closed loop control. A linear and a nonlinear control algorithm is used in combination. So we could combine a good dynamic behavior of the system with a good constantness of the control signal. We could make a very effective use of the motor and the power electronic converter.

   INVERTER AND CONVERTER THYRISTORS FIRING CONTROL FOR CSl-FED INDUCTION MOTOR
By G. Fekete; L. Szentirmai [View]
[Download]

Abstract: Current-source inverter (CSI) -fed induction motor drive was developed recently for 4-quadrant operation without reactor (inductive coil) should be interconnected in DC circuit. New converter and inverter logic maintain revolving magnetic field even in that case if current-conduction in stator-winding of induction motor is discontinuous. The conduction ranges of appropriate thyristor-pairs are provided by code-network and within these stages synchronous signal generator carries out synchronous firing of 4 thyristors in every instant. Favourable dynamic features have also been achieved in this way. Energy is returned into the mains while induction motor works in generator action. The new drive operates at the university above: control systems incorporate r.p.m. control with subordinate current control, then slip-frequency and torque-angle control as well. Theory has been verified by oscilloscope records and oscillograms. The new system having patent pending is suitable for induction motors up to 300 kilowatts rated power without reactor in DC circuit.

EPE 1985 - 10 - Lecture Session 2.03: CONTROL ALGORITHMS
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1985 - Conference > EPE 1985 - 10 - Lecture Session 2.03: CONTROL ALGORITHMS
	[return to parent folder]

	CASCADE ADAPTIVE SPEED CONTROL OF A THYRISTOR DRIVEN DC-MOTOR By V. Hahn; H. Unbehauen; R. M. Stephan	[View] [Download]
Abstract: A cascade speed control strategy for a thyristor driven DC-motor subjected to parameter variations, is proposed. A dual mode adaptive inner current loop is cascaded with a model reference adaptive speed control loop. The scheme is implemented in a 16-bit microcomputer using a floating point coprocessor. Tests on a DC-machine have been conducted. The proposed solution guarantees a stable and predefined performance under all operating conditions. Comparisons with a conventional analog speed control are made.

	SLIDING MODE CONTROL FOR ROBOTIC MANIPULATOR By F. Harashima; T. Ueshiba; H. Hashimoto; K. Maruyama	[View] [Download]
Abstract: The application of the sliding mode control based on VSS (Variable Structure System) for a multi-joint manipulator is presented. The high-gain effect of sliding mode control suppresses the complicated interactions between the each joints of a robot arm as well as the disturbances due to the parameter variations. The resulting system is completely robust whereas the obtained control law is simple and easy to be applied to on-line computer control. In this paper, the sliding mode controller is implemented to a two-linkage manipulator. The validity of this technique is confirmed in experiments where the system shows the robust performance in spite of the existing nonlinear interactions and unknown parametric changes.

	PARAMETER ADAPTIVE CONTROL OF INDUCTION MOTOR BASED ON STEADY STATE MACHINE MODEL By K. Harms; W. Leonhard	[View] [Download]
Abstract: The induction motor drive described in this paper consists of a voltage source PWM transistor inverter with current control loops producing approximately sinusoidal impressed stator currents in steady state. The amplitude and frequency of the current references are derived from a steady state machine model. In order to obtain good dynamic performance of the speed control loop the references are calculated with the assumption of constant air gap flux. Subsequently this condition is modified with the view of improved efficiency of motor and inverter by varying the air gap flux as a function of the load, causing the lightly loaded motor to operate at reduced flux. The feedback variables are two stator currents and speed which is measured by a digital sensor. All signal processing is performed by a single board microcomputer (CPU 80186) with an analog/digital interface card. As a result, a four quadrant drive with torque limit and good dynamic performance over a wide speed range is obtained, the response time of which is somewhat larger than in case of an optimal field orientated control scheme. However, the computational complexity is considerably reduced. In order to eliminate the effects caused by changing rotor temperature and desaturation in the field weakening region, the varying motor parameters are detected by on-line Fourier transformation of a stator current and a line to line voltage and subsequent updating of the controller parameters. This task is also performed by the microcomputer. The paper covers the underlying theory and demonstrates the design of an experimental 7.5 kW drive.

	INTELLIGENT DIGITAL FIRING CONTROLLER FOR IMPROVING THE POWER FACTOR OF FULLY CONTROLLED BRIDGE CONNECTIONS By V. Weiss; D. Naunin	[View] [Download]
Abstract: An intelligent digital firing controller will be presented, which can reduce the fundamental reactive power of fully controlled bridge connections with simultaneous control of the harmonic content for the line side current by making use of a new control method. The properties of the new control method will be shown. The features of the digital firing controller as well as the hardware realization will be discussed. Results from an electric drive with a converter cascade will be demonstrated.

	ADAPTIVE DIGITAL SPEED AND POSITION CONTROL OF DC-SERVO DRIVES By R. Schönfeld	[View] [Download]
Abstract: Position Drives are almost elastically coupled multimasse-systems with changeable parameters and changeable disturbance signals. In this contribution, simple adaptive structures are discussed, which enables a fast control of the position process undependent upon parameter changes and disturbances. The control is realised by small microcomputers. The state-space-control of the motion-process and adaptive structures using signal-selfadaption are discussed. If the range of parameter-changes is limited, a structure using signal-selfadaption enables a very good dynamic behavior of the closed loop control. A linear and a nonlinear control algorithm is used in combination. So we could combine a good dynamic behavior of the system with a good constantness of the control signal. We could make a very effective use of the motor and the power electronic converter.

	INVERTER AND CONVERTER THYRISTORS FIRING CONTROL FOR CSl-FED INDUCTION MOTOR By G. Fekete; L. Szentirmai	[View] [Download]
Abstract: Current-source inverter (CSI) -fed induction motor drive was developed recently for 4-quadrant operation without reactor (inductive coil) should be interconnected in DC circuit. New converter and inverter logic maintain revolving magnetic field even in that case if current-conduction in stator-winding of induction motor is discontinuous. The conduction ranges of appropriate thyristor-pairs are provided by code-network and within these stages synchronous signal generator carries out synchronous firing of 4 thyristors in every instant. Favourable dynamic features have also been achieved in this way. Energy is returned into the mains while induction motor works in generator action. The new drive operates at the university above: control systems incorporate r.p.m. control with subordinate current control, then slip-frequency and torque-angle control as well. Theory has been verified by oscilloscope records and oscillograms. The new system having patent pending is suitable for induction motors up to 300 kilowatts rated power without reactor in DC circuit.