EPE Association: EPE 2009 - subtopic 07-2 - DS: 'Application of Control Methods to Electrical Systems'

EPE 2009 - subtopic 07-2 - DS: 'Application of Control Methods to Electrical Systems'
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2009 - Conference > EPE 2009 - Topic 07: 'Application of Control Methods to Electrical Systems' > EPE 2009 - subtopic 07-2 - DS: 'Application of Control Methods to Electrical Systems'

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   A maximum speed of response control of switches-based system
By Anatoly BEKISHEV, Albert ISKHAKOV, Lev KLYACHKO, Vladimir POSPELOV, Sergey SKOVPEN [View]
[Download]

Abstract: A maximum speed of response control of switches-based system described by a second-order difference equation is proposed. A feedback is produced as a linear combination of the differences of system variables. The equation is transformed to the form with nilpotent matrix. The solution of the transformed difference equation converges into a fixed point after two steps. The equation is transformed with the help of a special matrix. The two matrix elements representing the multipliers at the differences of variables are determined. Depending on the loci of the elements in the matrix, the problem of their calculation is formulated as linear or non-linear. Its solution gives the two functions of elements of the matrix of difference equation. Variation of the elements leads to corresponding changes of multipliers and, as a result, a convergence of transient into a fixed point within two steps remains as well. The control principle proposed can provide a theoretical basis for developing switches-based systems with maximum possible dynamic behavior in the single point of nominal operating mode as well as in the region of parameters. The example of synthesis a control of pulsewidth converter used for current regulation in active-inductive load is resulted, which demonstrates significantly improvement of system dynamic behavior.

   A Neural Network Based Alternator Power Angle Estimation Method For Marine Electrical Network Supervision And Control
By Gang YAO, Guy LEBRET, Mourad AIT AHMED, Pedro Neiva KVIESKA, Tianhao TANG [View]
[Download]

Abstract: A neural network based alternator power angle estimation method is presented in this paper. The method is dedicated to detect load commutations in marine electrical network and to issue scheduling variables to gain scheduling controller. The global objective is to deal with the unexpected parameter oscillations problem in transient process when load commutations happen.

   A New Low Voltage Detecting Method for Multi-string LED BLU Circuits
By EUNCHUL KANG, Duckki KWON, Jaeeul YEON , Dongsoo KIM , WONHI OH [View]
[Download]

Abstract: This paper proposes a new lowest-voltage detecting circuit for multi-channel LED backlighting units (BLUs) for LCD TVs. The proposed circuit detects the lowest voltage drop among the multi-channel LED strings with reduced number of devices. After detecting such condition the circuit provides a feedback voltage to control the output voltage of the boost converter. Therefore, it can minimize the power losses in LED driving circuit. Experimental results are presented for a 15W boost converter driving 40mA, 8-channel LED strings.

   Comparison of Different Fault-Tolerant Control Strategies for Seven-Phase Induction Motor Drives
By Domenico CASADEI, Michele MENGONI, Giovanni SERRA, Angelo TANI, Luca ZARRI [View]
[Download]

Abstract: In this paper some different control strategies, suitable for open-phase fault operation of seven-phase current regulated induction motor drives, are presented. These strategies, which are valid in steady-state as well as in transient operating conditions, are compared in terms of stator and rotor copper losses and torque pulsations. The comparison is carried out by means of an opportune mathematical model of the machine that, exploiting the properties of the multiple space vector representation of multi-phase systems, takes into account the first five spatial harmonics of the air-gap magneto motive force. Some experimental tests carried out on a seven-phase asynchronous motor drive prototype confirm the characteristics of the proposed control strategies and the results of the theoretical comparison.

   Control of a Single Phase Voltage Source Inverter using the Monophasor Theory
By Stephan KENZELMANN, Philippe BARRADE, Yannick LOUVRIER, Alfred RUFER [View]
[Download]

Abstract: A method for simplifying the analytical treatment of single phase systems is introduced. This method, called monophasor theory, makes it possible to apply the same calculation methods and control strategies used for three-phase systems. This way, the spacial phasors of three-phase systems are translated into â€œmonophasorsâ€ for single-phase system. The presented approach is a generalisation of already existing attempts of single-phase system descriptions. The Monophasor theory is presented, together with an application example of single phase voltage source inverter.

   Control of system with the switched actuator rate limitation
By Algirdas BASKYS, Valerijus ZLOSNIKAS [View]
[Download]

Abstract: The control problem of the system with the switched actuator rate limitation is analyzed. The controller for plants, which include the actuator with the switched rate limitation, has been suggested. It is based on the algorithm, which differs from the conventional PI controller algorithm in the fact that the integral constant has different values during the plant output parameter rise and fall. The proposed controller allows us to achieve good quality of the control of plants with the switched actuator rate limitation. It was investigated using simulation and experimentally. The obtained results were compared to the results gained using the PI controller with the classical parallel structure, the PI controller with the anti-windup scheme and the PI controller with the two degrees of freedom scheme as well. The proposed controller is applied for control of differential air pressure of the industrial ventilation systems with the variable speed drive of the fan based on the AC induction motor supplied by the frequency converter, which acts as the actuator with the switched rate limitation.

   Current controller design for passivity of the input admittance
By Lennart HARNEFORS, Massimo BONGIORNO [View]
[Download]

Abstract: Current controller design for three-phase voltage-source converters, by which a passive input admittance is ideally obtained, is considered. Two design alternatives, with and without voltage feedforward, respectively, are shown to give similar performance. It is demonstrated how additional parts can be added to the controller while preserving the passivity property. This is applied particularly to resonant controllers.

   Design, Tuning and Testing of a Flexible PLL for Grid Synchronization of Three-Phase Power Converters
By Jon Are SUUL, Kjell LJÃ˜KELSÃ˜Y, Tore UNDELAND [View]
[Download]

Abstract: This paper is discussing a flexible three-phase Phase Locked Loop (PLL) with added functionality for grid voltage synchronization in a wide range of operating conditions. The presented structure is based on enhancing the well known Synchronous Reference Frame (SRF) PLL. Functions that modify the behaviour of the loop in order to handle large frequency and grid voltage deviations are also added. The PLL-structure is applicable for many applications with different control systems and different hardware, but is presented for grid synchronization of voltage source converters, with parts of the control system implemented in a Field Programmable Gate Array (FPGA). A simple tuning procedure based on analytical criteria has been developed and the system is analyzed in the frequency domain to verify the stability and illustrate the influence of the added functionality. Results from time-domain simulations and laboratory experiments are presented and discussed to verify the behaviour of the proposed PLL structure.

   GRID CONNECTED INVERTER BEHAVIOR WITH AN OUTPUT LC FILTER UNDER A VOLTAGE SAG OPERATION
By FOUAD SALHA, FrÃ©dÃ©ric COLAS, Xavier GUILLAUD [View]
[Download]

Abstract: The aim of this paper is to propose an over current limitation and voltage control strategy for a grid connected inverter with a LC output filter used in distributed generation and in case of voltage sag. This strategy relies on the control of LC output filter voltage with a resonant controller. This controller has to control current and load voltage throughout voltage sag. Generally, resonant controller is made up of a proportional and resonance term, which contains two imaginary poles that aimed to obtain an infinite gain at the resonance frequency. State feedback structure and pole assignment approach are used to tune the proposed control strategy. Comparative results for the application of both resonant and classical PI controller in d-q frame are showed in this paper. The last part deals with the implementation of control strategies on a real time simulation environment. The effectiveness of the proposed controller under a voltage sag operation is shown by experimental results.

   Harmonic Content Identification Based on Neural Method for Single-Phase Power Systems
By Sergio SILVA, Claudionor NASCIMENTO, Alessandro GOEDTEL, Azauri OLIVEIRA JÃšNIOR, Paulo JosÃ© SERNI [View]
[Download]

Abstract: An alternative method is presented in this paper to identify the harmonic components of non-linear loads in single phase power systems based on artificial neural networks. The components are identified by analyzing the single phase current waveform in time domain in half-cycle of the ac voltage source. The proposed method is compared to the fast Fourier transform. Simulation and experimental results are presented to validate the proposed approach.

   Improved Robust Phase Locked Loop for Utility Grid Applications
By Mohamed choukri BENHABIB, Fei WANG, Jorge DUARTE [View]
[Download]

Abstract: A phase locked loop (PLL) is an essential part of power-electronic converter control in utility grid applications, which is used to synchronize the control reference signals with the fundamental components of the grid voltages. In order to cope with different grid conditions such as voltage harmonics, voltage dips and frequency variations, an improved robust PLL with frequency-adaptive ability for large grid frequency changes is presented. Three different filtering methods for determining the estimated grid frequency are introduced and compared. The effectiveness of the improvement of robust PLL is verified by simulation and experimental results.

   On the Control Bandwidth of Servo Drives
By Joachim BOECKER, Stephan BEINEKE, Alexander BAEHR [View]
[Download]

Abstract: In this paper, the control performance of servo drives is being investigated. In this context, particular focus is put on the achievable control bandwidth, dependant on the chosen design parameters such as sampling rate, sampling strategy, and filter constants.

   Sliding Mode Control Of Boost Converter : Application to energy storage system via supercapacitors
By Alaa HIJAZI, Michael DI LORETO, Pascal VENET, Guy CLERC, Gerard ROJAT [View]
[Download]

Abstract: Sliding mode control of boost converter is studied. In order to improve dynamical performances with static and dynamic specifications, we propose a systematic procedure to compute the gains of the controller based on an optimization scheme. This method is applied to the control of an energy storage system based on supercapacitors technology in order to regulate the output voltage. Given a system with large variations of input voltage and load, it is necessary to guarantee good performance of the controller for large variations of operating point. Our study shows the great influence of the controller gains on the static and dynamic performances of the system. Hence, we point out a methodology for choosing the gains.

EPE 2009 - subtopic 07-2 - DS: 'Application of Control Methods to Electrical Systems'
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2009 - Conference > EPE 2009 - Topic 07: 'Application of Control Methods to Electrical Systems' > EPE 2009 - subtopic 07-2 - DS: 'Application of Control Methods to Electrical Systems'
	[return to parent folder]

	A maximum speed of response control of switches-based system By Anatoly BEKISHEV, Albert ISKHAKOV, Lev KLYACHKO, Vladimir POSPELOV, Sergey SKOVPEN	[View] [Download]
Abstract: A maximum speed of response control of switches-based system described by a second-order difference equation is proposed. A feedback is produced as a linear combination of the differences of system variables. The equation is transformed to the form with nilpotent matrix. The solution of the transformed difference equation converges into a fixed point after two steps. The equation is transformed with the help of a special matrix. The two matrix elements representing the multipliers at the differences of variables are determined. Depending on the loci of the elements in the matrix, the problem of their calculation is formulated as linear or non-linear. Its solution gives the two functions of elements of the matrix of difference equation. Variation of the elements leads to corresponding changes of multipliers and, as a result, a convergence of transient into a fixed point within two steps remains as well. The control principle proposed can provide a theoretical basis for developing switches-based systems with maximum possible dynamic behavior in the single point of nominal operating mode as well as in the region of parameters. The example of synthesis a control of pulsewidth converter used for current regulation in active-inductive load is resulted, which demonstrates significantly improvement of system dynamic behavior.

	A Neural Network Based Alternator Power Angle Estimation Method For Marine Electrical Network Supervision And Control By Gang YAO, Guy LEBRET, Mourad AIT AHMED, Pedro Neiva KVIESKA, Tianhao TANG	[View] [Download]
Abstract: A neural network based alternator power angle estimation method is presented in this paper. The method is dedicated to detect load commutations in marine electrical network and to issue scheduling variables to gain scheduling controller. The global objective is to deal with the unexpected parameter oscillations problem in transient process when load commutations happen.

	A New Low Voltage Detecting Method for Multi-string LED BLU Circuits By EUNCHUL KANG, Duckki KWON, Jaeeul YEON , Dongsoo KIM , WONHI OH	[View] [Download]
Abstract: This paper proposes a new lowest-voltage detecting circuit for multi-channel LED backlighting units (BLUs) for LCD TVs. The proposed circuit detects the lowest voltage drop among the multi-channel LED strings with reduced number of devices. After detecting such condition the circuit provides a feedback voltage to control the output voltage of the boost converter. Therefore, it can minimize the power losses in LED driving circuit. Experimental results are presented for a 15W boost converter driving 40mA, 8-channel LED strings.

	Comparison of Different Fault-Tolerant Control Strategies for Seven-Phase Induction Motor Drives By Domenico CASADEI, Michele MENGONI, Giovanni SERRA, Angelo TANI, Luca ZARRI	[View] [Download]
Abstract: In this paper some different control strategies, suitable for open-phase fault operation of seven-phase current regulated induction motor drives, are presented. These strategies, which are valid in steady-state as well as in transient operating conditions, are compared in terms of stator and rotor copper losses and torque pulsations. The comparison is carried out by means of an opportune mathematical model of the machine that, exploiting the properties of the multiple space vector representation of multi-phase systems, takes into account the first five spatial harmonics of the air-gap magneto motive force. Some experimental tests carried out on a seven-phase asynchronous motor drive prototype confirm the characteristics of the proposed control strategies and the results of the theoretical comparison.

	Control of a Single Phase Voltage Source Inverter using the Monophasor Theory By Stephan KENZELMANN, Philippe BARRADE, Yannick LOUVRIER, Alfred RUFER	[View] [Download]
Abstract: A method for simplifying the analytical treatment of single phase systems is introduced. This method, called monophasor theory, makes it possible to apply the same calculation methods and control strategies used for three-phase systems. This way, the spacial phasors of three-phase systems are translated into â€œmonophasorsâ€ for single-phase system. The presented approach is a generalisation of already existing attempts of single-phase system descriptions. The Monophasor theory is presented, together with an application example of single phase voltage source inverter.

	Control of system with the switched actuator rate limitation By Algirdas BASKYS, Valerijus ZLOSNIKAS	[View] [Download]
Abstract: The control problem of the system with the switched actuator rate limitation is analyzed. The controller for plants, which include the actuator with the switched rate limitation, has been suggested. It is based on the algorithm, which differs from the conventional PI controller algorithm in the fact that the integral constant has different values during the plant output parameter rise and fall. The proposed controller allows us to achieve good quality of the control of plants with the switched actuator rate limitation. It was investigated using simulation and experimentally. The obtained results were compared to the results gained using the PI controller with the classical parallel structure, the PI controller with the anti-windup scheme and the PI controller with the two degrees of freedom scheme as well. The proposed controller is applied for control of differential air pressure of the industrial ventilation systems with the variable speed drive of the fan based on the AC induction motor supplied by the frequency converter, which acts as the actuator with the switched rate limitation.

	Current controller design for passivity of the input admittance By Lennart HARNEFORS, Massimo BONGIORNO	[View] [Download]
Abstract: Current controller design for three-phase voltage-source converters, by which a passive input admittance is ideally obtained, is considered. Two design alternatives, with and without voltage feedforward, respectively, are shown to give similar performance. It is demonstrated how additional parts can be added to the controller while preserving the passivity property. This is applied particularly to resonant controllers.

	Design, Tuning and Testing of a Flexible PLL for Grid Synchronization of Three-Phase Power Converters By Jon Are SUUL, Kjell LJÃ˜KELSÃ˜Y, Tore UNDELAND	[View] [Download]
Abstract: This paper is discussing a flexible three-phase Phase Locked Loop (PLL) with added functionality for grid voltage synchronization in a wide range of operating conditions. The presented structure is based on enhancing the well known Synchronous Reference Frame (SRF) PLL. Functions that modify the behaviour of the loop in order to handle large frequency and grid voltage deviations are also added. The PLL-structure is applicable for many applications with different control systems and different hardware, but is presented for grid synchronization of voltage source converters, with parts of the control system implemented in a Field Programmable Gate Array (FPGA). A simple tuning procedure based on analytical criteria has been developed and the system is analyzed in the frequency domain to verify the stability and illustrate the influence of the added functionality. Results from time-domain simulations and laboratory experiments are presented and discussed to verify the behaviour of the proposed PLL structure.

	GRID CONNECTED INVERTER BEHAVIOR WITH AN OUTPUT LC FILTER UNDER A VOLTAGE SAG OPERATION By FOUAD SALHA, FrÃ©dÃ©ric COLAS, Xavier GUILLAUD	[View] [Download]
Abstract: The aim of this paper is to propose an over current limitation and voltage control strategy for a grid connected inverter with a LC output filter used in distributed generation and in case of voltage sag. This strategy relies on the control of LC output filter voltage with a resonant controller. This controller has to control current and load voltage throughout voltage sag. Generally, resonant controller is made up of a proportional and resonance term, which contains two imaginary poles that aimed to obtain an infinite gain at the resonance frequency. State feedback structure and pole assignment approach are used to tune the proposed control strategy. Comparative results for the application of both resonant and classical PI controller in d-q frame are showed in this paper. The last part deals with the implementation of control strategies on a real time simulation environment. The effectiveness of the proposed controller under a voltage sag operation is shown by experimental results.

	Harmonic Content Identification Based on Neural Method for Single-Phase Power Systems By Sergio SILVA, Claudionor NASCIMENTO, Alessandro GOEDTEL, Azauri OLIVEIRA JÃšNIOR, Paulo JosÃ© SERNI	[View] [Download]
Abstract: An alternative method is presented in this paper to identify the harmonic components of non-linear loads in single phase power systems based on artificial neural networks. The components are identified by analyzing the single phase current waveform in time domain in half-cycle of the ac voltage source. The proposed method is compared to the fast Fourier transform. Simulation and experimental results are presented to validate the proposed approach.

	Improved Robust Phase Locked Loop for Utility Grid Applications By Mohamed choukri BENHABIB, Fei WANG, Jorge DUARTE	[View] [Download]
Abstract: A phase locked loop (PLL) is an essential part of power-electronic converter control in utility grid applications, which is used to synchronize the control reference signals with the fundamental components of the grid voltages. In order to cope with different grid conditions such as voltage harmonics, voltage dips and frequency variations, an improved robust PLL with frequency-adaptive ability for large grid frequency changes is presented. Three different filtering methods for determining the estimated grid frequency are introduced and compared. The effectiveness of the improvement of robust PLL is verified by simulation and experimental results.

	On the Control Bandwidth of Servo Drives By Joachim BOECKER, Stephan BEINEKE, Alexander BAEHR	[View] [Download]
Abstract: In this paper, the control performance of servo drives is being investigated. In this context, particular focus is put on the achievable control bandwidth, dependant on the chosen design parameters such as sampling rate, sampling strategy, and filter constants.

	Sliding Mode Control Of Boost Converter : Application to energy storage system via supercapacitors By Alaa HIJAZI, Michael DI LORETO, Pascal VENET, Guy CLERC, Gerard ROJAT	[View] [Download]
Abstract: Sliding mode control of boost converter is studied. In order to improve dynamical performances with static and dynamic specifications, we propose a systematic procedure to compute the gains of the controller based on an optimization scheme. This method is applied to the control of an energy storage system based on supercapacitors technology in order to regulate the output voltage. Given a system with large variations of input voltage and load, it is necessary to guarantee good performance of the controller for large variations of operating point. Our study shows the great influence of the controller gains on the static and dynamic performances of the system. Hence, we point out a methodology for choosing the gains.