EPE Association: EPE 2005 - Topic 06-2 - DS: Application of control methods to electrical systems

EPE 2005 - Topic 06-2 - DS: Application of control methods to electrical systems
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2005 - Conference > EPE 2005 - Topic 06: APPLICATION OF CONTROL MODELS TO ELECTRICAL SYSTEMS > EPE 2005 - Topic 06-2 - DS: Application of control methods to electrical systems

   [return to parent folder]

   A Fuzzy PWM Direct Torque Control of Induction Machines for Current Limitation and Reduced Torque Ripple
By GIMENEZ Maria; ORTEGA Marcel; RESTREPO Jose; VIOLA Julio; GUZMAN Victor [View]
[Download]

Abstract: This paper presents a PWM-fuzzy direct torque controller for induction machines, with a current limiting function during start-up or for changes in the flux-linkage reference. The use of PWM in the controller ensures a constant switching frequency, and provides additional degrees of freedom to regulate the stator current, stator flux-linkage build-up and torque production. Also, these additional degrees of freedom provide smooth state variables, and a reduction in the torque ripple. The proposed scheme is verified by simulations and by experimental tests in a laboratory prototype.

   A Linear Parameter Variant Hinfinity Controller design for a Permanent Magnet Synchronous Machine
By DARENGOSSE Cedric; CHEVREL Philippe; MACHMOUM Mohamed; MACHMOUM Souad [View]
[Download]

Abstract: A robust decoupling current multivariable controller for a permanent synchronous machine is designed using a Linear Parameter Variant (LPV) of H¥ Control. This controller is scheduled with the rotor speed. Closed loop sensitivity functions analysis and simulation results evaluate the performance and the stability robustness of the resulting controller over all admissible PMSM operating range and under both unstructured disturbances related to the implementation and uncertainties in stator parameters.

   A Neuro-Fuzzy Multilayer Weights Approach for an On-Line Learning Speed Controller applied to a Switched Reluctance Machine: why and how to use it.
By RAFAEL Silviano [View]
[Download]

Abstract: The most used neuro-fuzzy motor speed control systems are time consuming and have an high computation effort when the speed reference changes suddenly and the system, most of the time, has to learn this new operating point. In this case a degradation of the system performance is evident, as is demonstrated by our experimental results in this paper. To surpass these effects, a new neuro-fuzzy multilayer control’s approach is proposed. The multilayer controller is tested and compared in the speed control system for an 8/6 switched reluctance motor by experimental tests. The proposed solution is explained, tested and the experimental results are presented and discussed.

   ARE NONLINEAR CONTROLLERS REALLY NECESSARY IN POWER ELECTRONICS DEVICES?
By SIRA-RAMINEZ Hebertt [View]
[Download]

Abstract: We demonstrate that linear, time varying, state feedback controllers, based on static passive output feedback, acting on exact open loop trajectory tracking error models of a large class of power electronics devices, semi-globally stabilize the trajectory tracking error to zero. The controllers are isomorphic to linear state feedback controllers, based on passivity and approximate linearization around the desired reference state trajectory. We present two design examples for rather different switched devices

   Artificial Neural Network control and energy management in 42 V DC link
By GUALOUS Hamid; MARI; BERTHON Alain [View]
[Download]

Abstract: This paper deals with an experimental realization of a 42V hybrid power sources for automotive applications. It’s composed by a battery which provides the power in constant mean power and a supercapacitor tank in order to supply power in transient state. Two DC/DC converters are used to adapt voltage and current levels between the 42V DC link, battery and supercapacitor tank. Voltage is regulated by using Artificial Neural Networks (ANNs).Supercapacitors have a high power density and low internal resistance, they can be charged and discharged at high current. They are ideally placed for peak power requirements. They can be used in parallel with battery to start the internal combustion engine in order to reduce the size of the batter, in hybrid vehicle to provide power during acceleration with the aim to reduce the power of the internal combustion engine …The study presented here is about experimental realization of a hybrid power source and its voltage control by ANN.

   Combining Exact Linearization and Model Reference Techniques for Design of Adaptive GAS Controller and Application to Adaptive Control of Induction Motor
By PHUOC Nguyen Doan [View]
[Download]

Abstract: The paper presents an adaptive global asymptotic stabilizing control scheme for the disturbance attenuation problem. Our design method combines exact linearization concept with model reference technique. The obtained controller makes the closed-loop system follow a given stable LTI model and hence global asymptotic stable. Simulation with doubly-fed induction motor model gives very promising results.

   Convergence Test of Model Reference Parameter Adaptive SRM Drives
By SZAMEL Laszlo [View]
[Download]

Abstract: Nowadays switched reluctance motor (SRM) drives have been widely used in the field of controlled electric motor drives. The paper proposes a model reference parameter adaptive control method for SRM drives. The main goal of the drive control is to improve dynamical performance by compensating for the motor nonlinearities. The adaptation practically works only in a relatively narrow speed error track (adaptation range) which is equal to approximately 20-100 revolution/min absolute value of speed error. The drawback of this limitation is the relatively short time for the algorithm to operate. But the convergence of the algorithm is extremely fast which significantly reduces the effect of this drawback. Two more important advantages emerge when adaptation works only with small speed errors. First of all the controller at changing drive parameters adapts to parameters around the value specified by speed reference signal which also assists to speed the adaptation. The other significant positive effect is the disappearing of the problem coming from nonlinear systems that the response of the system can even differ in its character when the value, amplitude of the reference signal is changed. The convergence test of this control method was performed in an experimental drive system. A SRM of 6/8 pole and 4 kW rated power was used. Simulation and experimental results are presented.

   Direct Model Predictive Control - A new Direct Predictive Control Strategy for Electrical Drives
By KENNEL Ralph; LINDER Arne [View]
[Download]

Abstract: Since more than 20 years the so-called "Field Oriented Control" is state-of-the-art for electrical drives. Strategies based on this principle fulfill nearly all demands of drive technology today. Due to its basic ideas, the performance of Field Oriented Control cannot be improved without limitations. Furthermore, linear controllers always produce a continuously valued output. Hence, for controlling an inverter additional components, which discretise the output of the controller, have to be inserted.Predictive Controllers, which allow to overcome this drawback, are known in drive control for quite a long time. Nevertheless all predictive control schemes proposed for controlling electrical drives until today only precalculate the system behaviour for one single future sampling cycle. Powerful control strategies like Model Predictive Control, well-known in chemical engineering, allow higher prediction horizons, but these strategies have not yet been used for drive control. This paper proposes a new predictive controller for electrical drives based on Model Predictive Control, which allows optimal control of the inverter directly, i.e. without using any kind of modulator. In contrast to all predictive strategies published so far for drive control, the new controller optimises the control action not only for the next sampling period, but for a longer prediction horizon.

   Flatness based control of three-phase boost rectifiers
By RUDOLPH Joachim; GENSIOR Albrecht; GUeLDNER Henry [View]
[Download]

Abstract: The flatness of the mathematical models of the three-phase three-wire and four-wire boost rectifiers is shown. Two trajectory planning algorithms are developed that enable fast voltage restoration after load steps by considering a load estimate. A load observer is suggested. Two tracking controllers are given. Simulations with a switched model show the value of the results.

   High Performance Control of Permanent Magnet Synchronous Motor Based on Magnetic Energy Model by Sliding Mode Control
By MURATA Toshiaki [View]
[Download]

Abstract: This paper presentsa field oriented direct torque control system in Permanent Magnet Synchronous Motor(PMSM) which controls torque directly as output. A PWM inverter-Fed PMSM control system has been driven by field oriented algorithm without chattering by sliding mode control. The validity of the proposed method is confirmed by simulation results.

   Intelligent measurement and control platform using Spartan3 FPGA
By RENTZSCH Martin; GUeLDNER Henry; LOSANSKY Jan [View]
[Download]

Abstract: Fast response of power electronic systems to events like load steps still is a domain of analogue controllers. Fast reconfigurable logic together with high rate Analogue to Digital Converter (ADC) opens this area for digital control. On-site data processing in FPGA minimizes risk of faulty transmission of analogue measurement data.

   Inverter DC-Link Stabilizing Control with Improved Voltage Sag Ride-Through Capability
By PIETILAeINEN Kai; HARNEFORS Lennart [View]
[Download]

Abstract: Previously published results concerning instability of the dc link in inverter drives fed from a dc grid or via a rectifier are extended in this paper. It is shown that rectifier-inverter drives equipped with small (film) dc-link capacitors may need active stabilization. The impact of limited bandwidth and switching frequency in the inverter-motor current control loop is considered. Recommendations for selection of the dc-link capacitor, the switching frequency, and the dc-link stabilization control law in relation to each other are given. The control law is incorporated in a previously proposed current controller, which is designed for good voltage sag ride-through capability.

   Load Current Estimation for Control Algorithms in Buck-Converter
By DERKSEN Sander; REEFMAN Derk [View]
[Download]

Abstract: In this paper a switching load current estimator for a buck converter is introduced. By combining two estimation principles in a single estimator, both a fast response and a high accuracy of the load current estimation can be obtained. The controller of the buck converter then uses this estimated load current, enabling it to respond fast on load changes and regulate the output voltage with high accuracy. Detailed descriptions of both types of estimation, their behavior and their combination are given. The load current estimator and the state feedback control algorithm have been implemented in a FPGA device. Experimental results from a buck converter controlled by the state feedback algorithm using the proposed switching load current estimator are presented.

   Online Diagnostics and Condition Monitoring in Voltage Source Inverters
By FRANKE Uwe [View]
[Download]

Abstract: This paper presents a method for online diagnostics and monitoring in voltage source inverters. Single components of the inverter prone to failure and aging are investigated and analysed. The proposed method allows for real time statistics and determination of gradual changes that would be difficult to estimate in an offline mode. Power semiconductors and other components of the voltage source inverter are considered and a more complete state report of the system can be given in real time. Practical measurements prove that the suggested diagnosis and monitoring approach can significantly contribute to better knowledge about the system’s state and help to recognise and overcome dangerous and critical states of voltage source inverters. Hence better utilisation and a more reliable power electronic system are obtained.

   Optimal Control Structure to reduce the commulative load in the drive train of Wind Energy Converters
By SOURKOUNIS Constantinos [View]
[Download]

Abstract: In principle the variable speed wind energy converters offer the technical possibilities to reduce thecumulative load in the drive train and the influence on the electrical grid. The short time wind powerfluctuations on the wind rotor can be smoothed by utilisation of rotating masses as storage of kineticenergy. This requires a special designed automatic control and system management, which minimiseselectric power fluctuation at maximum energy yield.Based on the named goals, a new control approach (fig. 2) has been conceived. These aims are achievedon base of stochastic dynamic optimisation algorithms. The new control approach considers the dynamicof the actual wind speed on the given location via a weight function on one hand and produces a directaction on the cumulative load for the plant´s drive train and the time dependent run of the electricalpower output curve by the formulation of quality functions on the other hand.The approach was tested with help of simulation and test plant, in which a variable speed wind energyconverter with the nominal power of 22 kVA is modulated under consideration of the separate systempart´s non-linear nature. The results of the new control approach are compared to conventional controlmethods.

   Post-Fault Operation of Fault-Tolerant Inverters for PMSM Drives
By WALLMARK Oskar; HARNEFORS Lennart; CARLSON Ola [View]
[Download]

Abstract: This paper considers post-fault operation of permanent-magnet synchronous motor drives equipped with a fault-tolerant inverter. In post-fault mode, the faulted phase is isolated and the neutral point is connected either to an additional inverter leg or to the midpoint of the dc bus. Different methods of controlling the neutral point voltage are presented and compared. Furthermore, operation without a position sensor (i.e., sensorless control) is considered and a modification to an estimator previously reported in the literature is proposed in order to take into account the effect of the asymmetry introduced due to the isolation of the faulted phase in post-fault mode. Simulations and experimental results are provided to support the theory and demonstrate the practical impact of the modifications proposed.

   Sensor Fault Detection for Fault Tolerant Vector Controlled Induction Machine
By BAGHLI Lotfi; REZZOUG Abderrezak; POURE Philipe [View]
[Download]

Abstract: This paper deals with instrument fault detection within a reconfigurable vector control scheme of induction motor. Current sensors failures are detected and reconfiguration of current measurement is achieved in order to allow continuous operation of the vector control. Simulation and experiments using a 5.5 kW machine are used to verify the theory.

   Simple Control Autotuning for PMSM Drives based on Feedback Relay
By TUBIANA Luca; MATTAVELLI Paolo; ZIGLIOTTO Mauro [View]
[Download]

Abstract: The rapid and precise tuning of speed and current controllers is a challenging issue in modern ac drives. So far, many different solutions have been proposed in the specialised literature, but they often describe highly sophisticated methods for special, high performance applications. Conversely, this paper proposes a very simple and effective autotuning technique, for both speed and current regulators, in permanent magnet synchronous motor drives.

   State-Space Control Structures for Buck Converters with/without Input Filter
By MYRZIK Johanna; LASCU Dan; KELLER GueNter [View]
[Download]

Abstract: Power supplies normally provide a constant output voltage. In most of the applications a DC/DC-converter is controlled by a voltage mode or a current mode controller. These controller types are well known and there are a lot of PWM controller ICs on the market. The controllers are often combined with feedforward techniques of the input voltage or output current, because these variables are disturbance variables. In this paper three state-space control structures are introduced. Based on the state-space representation an easy controller is designed first. The second one is improved as it works with an inner one-cycle controller and an outer I-controller for improving robustness. The third controller is designed for a buck converter with an input filter. The advantages of state-space controllers are pole placement and easy implementation. The input filter requires no resistor for damping and the filter elements can be much smaller. For each of the three controllers an example will be shown with controller design, simulation and results. Experimental results are shown for the state-space controller with inner one-cycle controller and outer I-controller.

EPE 2005 - Topic 06-2 - DS: Application of control methods to electrical systems
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2005 - Conference > EPE 2005 - Topic 06: APPLICATION OF CONTROL MODELS TO ELECTRICAL SYSTEMS > EPE 2005 - Topic 06-2 - DS: Application of control methods to electrical systems
	[return to parent folder]

	A Fuzzy PWM Direct Torque Control of Induction Machines for Current Limitation and Reduced Torque Ripple By GIMENEZ Maria; ORTEGA Marcel; RESTREPO Jose; VIOLA Julio; GUZMAN Victor	[View] [Download]
Abstract: This paper presents a PWM-fuzzy direct torque controller for induction machines, with a current limiting function during start-up or for changes in the flux-linkage reference. The use of PWM in the controller ensures a constant switching frequency, and provides additional degrees of freedom to regulate the stator current, stator flux-linkage build-up and torque production. Also, these additional degrees of freedom provide smooth state variables, and a reduction in the torque ripple. The proposed scheme is verified by simulations and by experimental tests in a laboratory prototype.

	A Linear Parameter Variant Hinfinity Controller design for a Permanent Magnet Synchronous Machine By DARENGOSSE Cedric; CHEVREL Philippe; MACHMOUM Mohamed; MACHMOUM Souad	[View] [Download]
Abstract: A robust decoupling current multivariable controller for a permanent synchronous machine is designed using a Linear Parameter Variant (LPV) of H¥ Control. This controller is scheduled with the rotor speed. Closed loop sensitivity functions analysis and simulation results evaluate the performance and the stability robustness of the resulting controller over all admissible PMSM operating range and under both unstructured disturbances related to the implementation and uncertainties in stator parameters.

	A Neuro-Fuzzy Multilayer Weights Approach for an On-Line Learning Speed Controller applied to a Switched Reluctance Machine: why and how to use it. By RAFAEL Silviano	[View] [Download]
Abstract: The most used neuro-fuzzy motor speed control systems are time consuming and have an high computation effort when the speed reference changes suddenly and the system, most of the time, has to learn this new operating point. In this case a degradation of the system performance is evident, as is demonstrated by our experimental results in this paper. To surpass these effects, a new neuro-fuzzy multilayer control’s approach is proposed. The multilayer controller is tested and compared in the speed control system for an 8/6 switched reluctance motor by experimental tests. The proposed solution is explained, tested and the experimental results are presented and discussed.

	ARE NONLINEAR CONTROLLERS REALLY NECESSARY IN POWER ELECTRONICS DEVICES? By SIRA-RAMINEZ Hebertt	[View] [Download]
Abstract: We demonstrate that linear, time varying, state feedback controllers, based on static passive output feedback, acting on exact open loop trajectory tracking error models of a large class of power electronics devices, semi-globally stabilize the trajectory tracking error to zero. The controllers are isomorphic to linear state feedback controllers, based on passivity and approximate linearization around the desired reference state trajectory. We present two design examples for rather different switched devices

	Artificial Neural Network control and energy management in 42 V DC link By GUALOUS Hamid; MARI; BERTHON Alain	[View] [Download]
Abstract: This paper deals with an experimental realization of a 42V hybrid power sources for automotive applications. It’s composed by a battery which provides the power in constant mean power and a supercapacitor tank in order to supply power in transient state. Two DC/DC converters are used to adapt voltage and current levels between the 42V DC link, battery and supercapacitor tank. Voltage is regulated by using Artificial Neural Networks (ANNs).Supercapacitors have a high power density and low internal resistance, they can be charged and discharged at high current. They are ideally placed for peak power requirements. They can be used in parallel with battery to start the internal combustion engine in order to reduce the size of the batter, in hybrid vehicle to provide power during acceleration with the aim to reduce the power of the internal combustion engine …The study presented here is about experimental realization of a hybrid power source and its voltage control by ANN.

	Combining Exact Linearization and Model Reference Techniques for Design of Adaptive GAS Controller and Application to Adaptive Control of Induction Motor By PHUOC Nguyen Doan	[View] [Download]
Abstract: The paper presents an adaptive global asymptotic stabilizing control scheme for the disturbance attenuation problem. Our design method combines exact linearization concept with model reference technique. The obtained controller makes the closed-loop system follow a given stable LTI model and hence global asymptotic stable. Simulation with doubly-fed induction motor model gives very promising results.

	Convergence Test of Model Reference Parameter Adaptive SRM Drives By SZAMEL Laszlo	[View] [Download]
Abstract: Nowadays switched reluctance motor (SRM) drives have been widely used in the field of controlled electric motor drives. The paper proposes a model reference parameter adaptive control method for SRM drives. The main goal of the drive control is to improve dynamical performance by compensating for the motor nonlinearities. The adaptation practically works only in a relatively narrow speed error track (adaptation range) which is equal to approximately 20-100 revolution/min absolute value of speed error. The drawback of this limitation is the relatively short time for the algorithm to operate. But the convergence of the algorithm is extremely fast which significantly reduces the effect of this drawback. Two more important advantages emerge when adaptation works only with small speed errors. First of all the controller at changing drive parameters adapts to parameters around the value specified by speed reference signal which also assists to speed the adaptation. The other significant positive effect is the disappearing of the problem coming from nonlinear systems that the response of the system can even differ in its character when the value, amplitude of the reference signal is changed. The convergence test of this control method was performed in an experimental drive system. A SRM of 6/8 pole and 4 kW rated power was used. Simulation and experimental results are presented.

	Direct Model Predictive Control - A new Direct Predictive Control Strategy for Electrical Drives By KENNEL Ralph; LINDER Arne	[View] [Download]
Abstract: Since more than 20 years the so-called "Field Oriented Control" is state-of-the-art for electrical drives. Strategies based on this principle fulfill nearly all demands of drive technology today. Due to its basic ideas, the performance of Field Oriented Control cannot be improved without limitations. Furthermore, linear controllers always produce a continuously valued output. Hence, for controlling an inverter additional components, which discretise the output of the controller, have to be inserted.Predictive Controllers, which allow to overcome this drawback, are known in drive control for quite a long time. Nevertheless all predictive control schemes proposed for controlling electrical drives until today only precalculate the system behaviour for one single future sampling cycle. Powerful control strategies like Model Predictive Control, well-known in chemical engineering, allow higher prediction horizons, but these strategies have not yet been used for drive control. This paper proposes a new predictive controller for electrical drives based on Model Predictive Control, which allows optimal control of the inverter directly, i.e. without using any kind of modulator. In contrast to all predictive strategies published so far for drive control, the new controller optimises the control action not only for the next sampling period, but for a longer prediction horizon.

	Flatness based control of three-phase boost rectifiers By RUDOLPH Joachim; GENSIOR Albrecht; GUeLDNER Henry	[View] [Download]
Abstract: The flatness of the mathematical models of the three-phase three-wire and four-wire boost rectifiers is shown. Two trajectory planning algorithms are developed that enable fast voltage restoration after load steps by considering a load estimate. A load observer is suggested. Two tracking controllers are given. Simulations with a switched model show the value of the results.

	High Performance Control of Permanent Magnet Synchronous Motor Based on Magnetic Energy Model by Sliding Mode Control By MURATA Toshiaki	[View] [Download]
Abstract: This paper presentsa field oriented direct torque control system in Permanent Magnet Synchronous Motor(PMSM) which controls torque directly as output. A PWM inverter-Fed PMSM control system has been driven by field oriented algorithm without chattering by sliding mode control. The validity of the proposed method is confirmed by simulation results.

	Intelligent measurement and control platform using Spartan3 FPGA By RENTZSCH Martin; GUeLDNER Henry; LOSANSKY Jan	[View] [Download]
Abstract: Fast response of power electronic systems to events like load steps still is a domain of analogue controllers. Fast reconfigurable logic together with high rate Analogue to Digital Converter (ADC) opens this area for digital control. On-site data processing in FPGA minimizes risk of faulty transmission of analogue measurement data.

	Inverter DC-Link Stabilizing Control with Improved Voltage Sag Ride-Through Capability By PIETILAeINEN Kai; HARNEFORS Lennart	[View] [Download]
Abstract: Previously published results concerning instability of the dc link in inverter drives fed from a dc grid or via a rectifier are extended in this paper. It is shown that rectifier-inverter drives equipped with small (film) dc-link capacitors may need active stabilization. The impact of limited bandwidth and switching frequency in the inverter-motor current control loop is considered. Recommendations for selection of the dc-link capacitor, the switching frequency, and the dc-link stabilization control law in relation to each other are given. The control law is incorporated in a previously proposed current controller, which is designed for good voltage sag ride-through capability.

	Load Current Estimation for Control Algorithms in Buck-Converter By DERKSEN Sander; REEFMAN Derk	[View] [Download]
Abstract: In this paper a switching load current estimator for a buck converter is introduced. By combining two estimation principles in a single estimator, both a fast response and a high accuracy of the load current estimation can be obtained. The controller of the buck converter then uses this estimated load current, enabling it to respond fast on load changes and regulate the output voltage with high accuracy. Detailed descriptions of both types of estimation, their behavior and their combination are given. The load current estimator and the state feedback control algorithm have been implemented in a FPGA device. Experimental results from a buck converter controlled by the state feedback algorithm using the proposed switching load current estimator are presented.

	Online Diagnostics and Condition Monitoring in Voltage Source Inverters By FRANKE Uwe	[View] [Download]
Abstract: This paper presents a method for online diagnostics and monitoring in voltage source inverters. Single components of the inverter prone to failure and aging are investigated and analysed. The proposed method allows for real time statistics and determination of gradual changes that would be difficult to estimate in an offline mode. Power semiconductors and other components of the voltage source inverter are considered and a more complete state report of the system can be given in real time. Practical measurements prove that the suggested diagnosis and monitoring approach can significantly contribute to better knowledge about the system’s state and help to recognise and overcome dangerous and critical states of voltage source inverters. Hence better utilisation and a more reliable power electronic system are obtained.

	Optimal Control Structure to reduce the commulative load in the drive train of Wind Energy Converters By SOURKOUNIS Constantinos	[View] [Download]
Abstract: In principle the variable speed wind energy converters offer the technical possibilities to reduce thecumulative load in the drive train and the influence on the electrical grid. The short time wind powerfluctuations on the wind rotor can be smoothed by utilisation of rotating masses as storage of kineticenergy. This requires a special designed automatic control and system management, which minimiseselectric power fluctuation at maximum energy yield.Based on the named goals, a new control approach (fig. 2) has been conceived. These aims are achievedon base of stochastic dynamic optimisation algorithms. The new control approach considers the dynamicof the actual wind speed on the given location via a weight function on one hand and produces a directaction on the cumulative load for the plant´s drive train and the time dependent run of the electricalpower output curve by the formulation of quality functions on the other hand.The approach was tested with help of simulation and test plant, in which a variable speed wind energyconverter with the nominal power of 22 kVA is modulated under consideration of the separate systempart´s non-linear nature. The results of the new control approach are compared to conventional controlmethods.

	Post-Fault Operation of Fault-Tolerant Inverters for PMSM Drives By WALLMARK Oskar; HARNEFORS Lennart; CARLSON Ola	[View] [Download]
Abstract: This paper considers post-fault operation of permanent-magnet synchronous motor drives equipped with a fault-tolerant inverter. In post-fault mode, the faulted phase is isolated and the neutral point is connected either to an additional inverter leg or to the midpoint of the dc bus. Different methods of controlling the neutral point voltage are presented and compared. Furthermore, operation without a position sensor (i.e., sensorless control) is considered and a modification to an estimator previously reported in the literature is proposed in order to take into account the effect of the asymmetry introduced due to the isolation of the faulted phase in post-fault mode. Simulations and experimental results are provided to support the theory and demonstrate the practical impact of the modifications proposed.

	Sensor Fault Detection for Fault Tolerant Vector Controlled Induction Machine By BAGHLI Lotfi; REZZOUG Abderrezak; POURE Philipe	[View] [Download]
Abstract: This paper deals with instrument fault detection within a reconfigurable vector control scheme of induction motor. Current sensors failures are detected and reconfiguration of current measurement is achieved in order to allow continuous operation of the vector control. Simulation and experiments using a 5.5 kW machine are used to verify the theory.

	Simple Control Autotuning for PMSM Drives based on Feedback Relay By TUBIANA Luca; MATTAVELLI Paolo; ZIGLIOTTO Mauro	[View] [Download]
Abstract: The rapid and precise tuning of speed and current controllers is a challenging issue in modern ac drives. So far, many different solutions have been proposed in the specialised literature, but they often describe highly sophisticated methods for special, high performance applications. Conversely, this paper proposes a very simple and effective autotuning technique, for both speed and current regulators, in permanent magnet synchronous motor drives.

	State-Space Control Structures for Buck Converters with/without Input Filter By MYRZIK Johanna; LASCU Dan; KELLER GueNter	[View] [Download]
Abstract: Power supplies normally provide a constant output voltage. In most of the applications a DC/DC-converter is controlled by a voltage mode or a current mode controller. These controller types are well known and there are a lot of PWM controller ICs on the market. The controllers are often combined with feedforward techniques of the input voltage or output current, because these variables are disturbance variables. In this paper three state-space control structures are introduced. Based on the state-space representation an easy controller is designed first. The second one is improved as it works with an inner one-cycle controller and an outer I-controller for improving robustness. The third controller is designed for a buck converter with an input filter. The advantages of state-space controllers are pole placement and easy implementation. The input filter requires no resistor for damping and the filter elements can be much smaller. For each of the three controllers an example will be shown with controller design, simulation and results. Experimental results are shown for the state-space controller with inner one-cycle controller and outer I-controller.