EPE Association: EPE 1999 - Topic 04a: Fuzzy Control Methods

EPE 1999 - Topic 04a: Fuzzy Control Methods
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1999 - Conference > EPE 1999 - Topic 04: CONTROL > EPE 1999 - Topic 04a: Fuzzy Control Methods

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   A Neural Network-based Current Control Scheme for a 3-level Inverter
By J.Y. Choi; I. Choy; J.H.Song; S.C. Lee [View]
[Download]

Abstract: This paper presents the design of a new current controleer for a three-level inverter using neural networks (NNs). From the past experience, the unbalance of DC-link voltage in the three-level inverters causes a low power factor and an increased harmonics to induction motors. The proposed current control scheme offers "tight DC-link voltage balancing" for the inverter along with nonlinear mapping of essential switching patterns and fault tolerance, which are inherent characteristics of NNs. Both computer simulation and experimental results show that the proposed new current control scheme provides an excellent fault tolerance characteristic compared with conventional hysteresis and sinusoidal pulse-width-modulation (SPWM) current control to loss of one phase information.

   A New Approach to Fuzzy Rules Extraction for Electrical Drive Control
By S. Carmeli; F. Castelli Dezza; A. Monti [View]
[Download]

Abstract: This paper presents a new approach to the problem of fuzzy rules extraction. Aim of the work is to preserve the typical fuzzy logic characteristics of immediacy and deductibility. The method derives fuzzy relations between inputs and outputs starting from sampling system data: a fuzzy translation phase allows to directly obtain the fuzzy membership and rules. The method requires only one decision: the number of fuzzy sets. This approach has been applied to electrical drives field and has been tested with good results both in simulation and in a laboratory prototype. An interesting solution software implementation in low cost microcontrollers is also proposed.

   A New Fuzzy Logic Control Scheme for Three-Phase AC/DC PWM Converters Implemented in a DSP
By F. Stergiopoulos; H. Zelaya de la Parra; A.J. Forsyth [View]
[Download]

Abstract: This paper presents a novel fuzzy logic control scheme for three-phase unity power factor AC/DC converters. It has the significant advantage of being simple with a small number of control rules and does not require a mathematical representation (e.g. small-signal modelling) of the system. The proposed controller has been implemented in the laboratory using a TMS320C30 Digital Signal Processor where it has been seen that a fast response with small overshoots or undershoots can be achieved even when disturbances (e.g. load increase) occur.

   Fuzzy Adaptive Speed Controller Without Reference Model
By D. Bedford; J. L. Romeral; A. Arias; E. Aldabas [View]
[Download]

Abstract: The authors present an Adaptive Fuzzy Controller for AC motor speed regulation with a particular form of self-adaption without reference model, and therefore with a low computational algorithm. The control continuously measures the dynamic characteristics of the system, given by total accumulated error between set value and real speed, and uses it to vary fuzzy system parameters, in this case physical shape of membership fuzzy functions. the developed controller has been compared with other classical controls, as standard non-adaptive PID control and fuzzy control. Simulated results presented in the paper demonstrate that this algorithm is better than other classical PID and fuzzy controls, in terms of the performance selected index, the Integral of Absolute Error, IAE, which it should tend to minimum imposed by the constant time of the physical system. as is also shown, the algorithm is more robust than those others in front of plant parameters changes, specifically, the moment of inertia and the load torque. The dynamic simulation results of the whole drive are supported with experimental data.

   Fuzzy Logic Based Stator Flux Oriented Control of the DFSM
By A. Masmoudi; N. Derbel; A. Ouali [View]
[Download]

Abstract: Much attention is presently focused upon the doubly fed synchronous machine (DFSM) both at an academic level, as an interesting topic of research, and at an applied level, as an efficient machine for variable speed drives. the paper deals with the implementation of a stator flux oriented control system in a DFSM drive. The main contribution of this work consists of the substitution of the classical PI controllers, considered in previous studies, by fuzzy PI controllers. It has been found that a CRPWM voltage converter including hysteresis (bang-bang) controllers could efficiently match with the fuzzy logic control strategy. The stator flux oriented control system turns to be much more robust against the DFSM parameter variations, and the load disturbances.

   Fuzzy Logic Control of a Single Phase AC/DC Buck-Boost Converter
By V. Fernao Pires; T. G. Amaral; J. Fernando Silva; M. Crisóstomo [View]
[Download]

Abstract: This paper describes a Fuzzy Logic Controller for the output voltage of a single phase ac/dc Buck-Boost converters. The use of these rectifiers with a suitable PWM current controller, ensure a near unity power factor operation and input current with low harmonic content. The reference of the current controller is a sinusoidal waveform whose amplitude is modulated by the external voltage controller. Usually, the well-known Proportional Integral (PI- Controller is used for the voltage controller. However, the relationship between the amplitude of the input current and the output voltage is non-linear and depends on the load. Therefore, the PI-parameters are not constant. To correct this problem, a fuzzy logic controller is derived. Simulation results are presented, and the performances of the Fuzzy Logic Controller are compared with the behavior of the widely used Proportional Integral (PI) output voltage control, aided by a inner loop for the PWM current mode modulator.

   Fuzzy Logic to Correct Power Factor Considering Power Quality
By R. M. Martins; A. de Oliveira; S. Ferreira de Paula Silva [View]
[Download]

Abstract: The use of capacitors for correcting the power factor is a very well known approach in industry. However, the increase of harmonic sources in power systems is heightening the risk of resonance and, consequently, a drastic decrease in electric power quality. In order to keep the rating voltage, the power factor, and the voltage and current harmonic distortions within acceptable limits, a fuzzy control approach was implemented. Based on this approach, a software program that is able to decide about the optimal distribution of the capacitor banks has also been developed. The program decision is based of the rating voltage, the power factor and the whole voltage and current harmonic distortions. When necessary, the computer program decides on the use of filters for harmonic compensation, indicating the best filter and the corresponding tuning frequency. Furthermore, the approach is able to deal with some aspects concerning the electric losses, both on the rating frequency and on the harmonic components.

   Neural Network Approach for Power Factor Correction of PMW AC/DC Voltage Source Converters
By S. Meo; A. Perfetto [View]
[Download]

Abstract: The paper deals with a neural network approach for the control of ac/dc PWM voltage source converter. Al will be shown, this control guarantees a line currents closed to sinusoidal, with unity power factor and has very good dynamic response both to step changes in the dc load current and reference voltage. At end it gives a sufficient stability region, independant of the circuit parameters, against large-signal disturbances and can adequately control the rectifier over a wide range of operating conditions.

   Neuro-Fuzzy Vector Control of a Broken-Bar Induction Motor
By L. Baghli; A. Abed; H. Razik; A. Rezzoug. [View]
[Download]

Abstract: This paper is intended to show the behaviour of vector controlled induction motors when rotor-bars break. The motor operates in a vector controlled scheme. Thanks to a neuro-fuzzy speed controller, motor torque ripple is compensated by an oscillatory command torque. Moreover, analysis of Iqs stator current component can be used in order to diagnose rotor failures.

EPE 1999 - Topic 04a: Fuzzy Control Methods
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1999 - Conference > EPE 1999 - Topic 04: CONTROL > EPE 1999 - Topic 04a: Fuzzy Control Methods
	[return to parent folder]

	A Neural Network-based Current Control Scheme for a 3-level Inverter By J.Y. Choi; I. Choy; J.H.Song; S.C. Lee	[View] [Download]
Abstract: This paper presents the design of a new current controleer for a three-level inverter using neural networks (NNs). From the past experience, the unbalance of DC-link voltage in the three-level inverters causes a low power factor and an increased harmonics to induction motors. The proposed current control scheme offers "tight DC-link voltage balancing" for the inverter along with nonlinear mapping of essential switching patterns and fault tolerance, which are inherent characteristics of NNs. Both computer simulation and experimental results show that the proposed new current control scheme provides an excellent fault tolerance characteristic compared with conventional hysteresis and sinusoidal pulse-width-modulation (SPWM) current control to loss of one phase information.

	A New Approach to Fuzzy Rules Extraction for Electrical Drive Control By S. Carmeli; F. Castelli Dezza; A. Monti	[View] [Download]
Abstract: This paper presents a new approach to the problem of fuzzy rules extraction. Aim of the work is to preserve the typical fuzzy logic characteristics of immediacy and deductibility. The method derives fuzzy relations between inputs and outputs starting from sampling system data: a fuzzy translation phase allows to directly obtain the fuzzy membership and rules. The method requires only one decision: the number of fuzzy sets. This approach has been applied to electrical drives field and has been tested with good results both in simulation and in a laboratory prototype. An interesting solution software implementation in low cost microcontrollers is also proposed.

	A New Fuzzy Logic Control Scheme for Three-Phase AC/DC PWM Converters Implemented in a DSP By F. Stergiopoulos; H. Zelaya de la Parra; A.J. Forsyth	[View] [Download]
Abstract: This paper presents a novel fuzzy logic control scheme for three-phase unity power factor AC/DC converters. It has the significant advantage of being simple with a small number of control rules and does not require a mathematical representation (e.g. small-signal modelling) of the system. The proposed controller has been implemented in the laboratory using a TMS320C30 Digital Signal Processor where it has been seen that a fast response with small overshoots or undershoots can be achieved even when disturbances (e.g. load increase) occur.

	Fuzzy Adaptive Speed Controller Without Reference Model By D. Bedford; J. L. Romeral; A. Arias; E. Aldabas	[View] [Download]
Abstract: The authors present an Adaptive Fuzzy Controller for AC motor speed regulation with a particular form of self-adaption without reference model, and therefore with a low computational algorithm. The control continuously measures the dynamic characteristics of the system, given by total accumulated error between set value and real speed, and uses it to vary fuzzy system parameters, in this case physical shape of membership fuzzy functions. the developed controller has been compared with other classical controls, as standard non-adaptive PID control and fuzzy control. Simulated results presented in the paper demonstrate that this algorithm is better than other classical PID and fuzzy controls, in terms of the performance selected index, the Integral of Absolute Error, IAE, which it should tend to minimum imposed by the constant time of the physical system. as is also shown, the algorithm is more robust than those others in front of plant parameters changes, specifically, the moment of inertia and the load torque. The dynamic simulation results of the whole drive are supported with experimental data.

	Fuzzy Logic Based Stator Flux Oriented Control of the DFSM By A. Masmoudi; N. Derbel; A. Ouali	[View] [Download]
Abstract: Much attention is presently focused upon the doubly fed synchronous machine (DFSM) both at an academic level, as an interesting topic of research, and at an applied level, as an efficient machine for variable speed drives. the paper deals with the implementation of a stator flux oriented control system in a DFSM drive. The main contribution of this work consists of the substitution of the classical PI controllers, considered in previous studies, by fuzzy PI controllers. It has been found that a CRPWM voltage converter including hysteresis (bang-bang) controllers could efficiently match with the fuzzy logic control strategy. The stator flux oriented control system turns to be much more robust against the DFSM parameter variations, and the load disturbances.

	Fuzzy Logic Control of a Single Phase AC/DC Buck-Boost Converter By V. Fernao Pires; T. G. Amaral; J. Fernando Silva; M. Crisóstomo	[View] [Download]
Abstract: This paper describes a Fuzzy Logic Controller for the output voltage of a single phase ac/dc Buck-Boost converters. The use of these rectifiers with a suitable PWM current controller, ensure a near unity power factor operation and input current with low harmonic content. The reference of the current controller is a sinusoidal waveform whose amplitude is modulated by the external voltage controller. Usually, the well-known Proportional Integral (PI- Controller is used for the voltage controller. However, the relationship between the amplitude of the input current and the output voltage is non-linear and depends on the load. Therefore, the PI-parameters are not constant. To correct this problem, a fuzzy logic controller is derived. Simulation results are presented, and the performances of the Fuzzy Logic Controller are compared with the behavior of the widely used Proportional Integral (PI) output voltage control, aided by a inner loop for the PWM current mode modulator.

	Fuzzy Logic to Correct Power Factor Considering Power Quality By R. M. Martins; A. de Oliveira; S. Ferreira de Paula Silva	[View] [Download]
Abstract: The use of capacitors for correcting the power factor is a very well known approach in industry. However, the increase of harmonic sources in power systems is heightening the risk of resonance and, consequently, a drastic decrease in electric power quality. In order to keep the rating voltage, the power factor, and the voltage and current harmonic distortions within acceptable limits, a fuzzy control approach was implemented. Based on this approach, a software program that is able to decide about the optimal distribution of the capacitor banks has also been developed. The program decision is based of the rating voltage, the power factor and the whole voltage and current harmonic distortions. When necessary, the computer program decides on the use of filters for harmonic compensation, indicating the best filter and the corresponding tuning frequency. Furthermore, the approach is able to deal with some aspects concerning the electric losses, both on the rating frequency and on the harmonic components.

	Neural Network Approach for Power Factor Correction of PMW AC/DC Voltage Source Converters By S. Meo; A. Perfetto	[View] [Download]
Abstract: The paper deals with a neural network approach for the control of ac/dc PWM voltage source converter. Al will be shown, this control guarantees a line currents closed to sinusoidal, with unity power factor and has very good dynamic response both to step changes in the dc load current and reference voltage. At end it gives a sufficient stability region, independant of the circuit parameters, against large-signal disturbances and can adequately control the rectifier over a wide range of operating conditions.

	Neuro-Fuzzy Vector Control of a Broken-Bar Induction Motor By L. Baghli; A. Abed; H. Razik; A. Rezzoug.	[View] [Download]
Abstract: This paper is intended to show the behaviour of vector controlled induction motors when rotor-bars break. The motor operates in a vector controlled scheme. Thanks to a neuro-fuzzy speed controller, motor torque ripple is compensated by an oscillatory command torque. Moreover, analysis of Iqs stator current component can be used in order to diagnose rotor failures.