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Showing papers presented at "International Symposium on Industrial Electronics in 2004"


Proceedings ArticleDOI
04 May 2004
TL;DR: In this article, the influence of rolling-element bearing faults on induction motor stator current has been investigated and a new detailed approach is proposed based on two effects of a bearing fault: the introduction of a particular radial rotor movement and load torque variations caused by the bearing fault.
Abstract: This paper describes new models for the influence of rolling-element bearing faults on induction motor stator current. Bearing problems are one major cause for drive failures. Their detection is possible by vibration monitoring of characteristic bearing frequencies. As it is possible to detect other machine faults by monitoring the stator current, a great interest exists in applying the same method for bearing fault detection. After a presentation of the existing fault model, a new detailed approach is proposed. It is based on two effects of a bearing fault: the introduction of a particular radial rotor movement and load torque variations caused by the bearing fault. The theoretical study results in new expressions for the stator current frequency content. Experimental tests with artificial and realistic bearing damage were conducted by measuring vibration, torque and stator current. The obtained results by spectral analysis of the measured quantities validate the proposed theoretical approach.

174 citations


Proceedings ArticleDOI
04 May 2004
TL;DR: In this paper, the P/Q droop method is used to avoid any communication among the modules in order to achieve stable output impedance value, and therefore, proper power balance is guaranteed when sharing both linear and nonlinear loads.
Abstract: This paper deals with the design of the output impedance of UPS inverters with parallel-connection capability. The inner control loops are considered in the design of the controllers that makes possible the power sharing among the UPS modules. In these paralleled units, the power-sharing outer control loops are based on the P/Q droop method in order to avoid any communication among the modules. The power sharing accuracy is highly sensitive to the output impedance of the inverters, making necessary the tight adjustment of this impedance. Novel control loops are proposed to achieve stable output impedance value, and, therefore, proper power balance is guarantee when sharing both linear and nonlinear loads.

103 citations


Proceedings ArticleDOI
04 May 2004
TL;DR: In this article, the axial leakage flux spectrum was used to detect incipient stator inter-turn short-circuits in a three-phase squirrel-cage induction machine, in the presence of voltage source dissymmetry.
Abstract: The aim of this paper is to develop a tool for condition monitoring of squirrel-cage three-phase induction machines using axial flux measurement. The emf induced in a search coil which is proportional to the axial flux derivative, is measured in order to detect, in presence of voltage source dissymmetry, incipient stator inter-turn short-circuits in working induction machines. Starting from a theoretical analysis of the axial leakage flux spectrum associated to this fault, the measurement of the corresponding emf in the search coil is examined. The proposed simplified axial flux spectrum gives directly the sensitive frequency components to study faults for both no-load and rated-load operations. This spectrum enables us to observe directly the evolution of these components during the fault conditions, materialized by the presence of a few stator inter-turn short-circuits, compared to normal operation. An experimental test-bed with a 230 V/400 V-50 Hz-11 kW three-phase squirrel-cage induction machine has been used to verify the efficiency of this tool. Finally, the performance of the proposed technique is proved experimentally.

68 citations


Proceedings ArticleDOI
04 May 2004
TL;DR: In this article, a comparative study of these control strategies and architectures is proposed based on simulations and on some experiments, where the analysis is based on simulation and some experiments and it is also based on fuzzy logic.
Abstract: Power characteristics of wind turbines are nonlinear It is particularly true for Savonius vertical axis systems whose the provided power is very sensitive to the load Thus, controlling its operating is essential to optimise the energetic behaviour Several control strategies (maximum power point tracking) can be used for energy conversion If the wind turbine characteristic (Cp(/spl lambda/)) is supposed to be a priori known, it can be used for an optimal control of the torque, speed or of the output current On the contrary, if this characteristic is unknown, an operational seeking algorithm such as fuzzy logic has to be implemented Several structures are also possible following the AC-DC converter which can be a PWM converter or a simple diode bridge A comparative study of these control strategies and architectures is proposed in this paper The analysis is based on simulations and on some experiments

66 citations


Proceedings ArticleDOI
04 May 2004
TL;DR: In this paper, the perturb and observe (P&O) maximum power point tracking (MPPT) algorithm can be confused due to the fact that it is not able to distinguish the variations of the photovoltaic array output power caused by duty cycle modulation from those ones caused by the irradiance variation.
Abstract: In presence of rapidly changing atmospheric conditions, the perturb and observe (P&O) maximum power point tracking (MPPT) algorithm can be confused due to the fact that it is not able to distinguish the variations of the photovoltaic array output power caused by the duty cycle modulation from those ones caused by the irradiance variation. In this paper, it is shown that the negative effects associated to such a drawback can be greatly reduced if the magnitude of the duty-cycle perturbations is customized to the dynamic behavior of the specific dc-dc converter adopted to realize the P&O MPPT. As an example, a boost battery charger has been studied.

50 citations


Proceedings ArticleDOI
04 May 2004
TL;DR: In this paper, a perturb and observe (P&O) maximum power point tracking (MPPT) control technique can be improved by optimizing its sampling interval T/sub a/ according to the converter's dynamics.
Abstract: This paper shows that the efficiency of the perturb and observe (P&O) maximum power point tracking (MPPT) control technique can be improved by optimizing its sampling interval T/sub a/ according to the converter's dynamics. During sunny days, when the maximum power point of the photovoltaic (PV) array moves very slowly, the sampling interval T/sub a/ must be set as short as possible without causing instability. If the algorithm samples the array voltage and current too quickly, it is subjected to possible mistakes caused by the transient behavior of the PV array+converter system, thus missing temporarily the MPP. As a consequence, the algorithm can be confused, the energy efficiency decays, and the operating point can become unstable, entering disordered behaviors. The solution proposed in this paper lies in choosing T/sub a/ according to the converter's dynamics. The choice of the value of T/sub a/ according to the proposed approach ensures a three-level steady-state duty-cycle swing around the MPP, whatever the duty-cycle step-size and the irradiance level are. As an example, a boost MPPT battery charger has been studied.

49 citations


Proceedings ArticleDOI
04 May 2004
TL;DR: In this paper, a voltage and current conditioning system is proposed for a multiple input dc-dc power electronic converter (MIPEC) devoted to combine hybrid-electric vehicles (HEV) different on-board energy sources; the proposed arrangement for the propulsion system includes fuel cell (FC), ultra-capacitor (UC) tank, and battery unit system (BU).
Abstract: In this paper design of voltage and current conditioning system is proposed for a multiple input dc-dc power electronic converter (MIPEC) devoted to combine hybrid-electric vehicles (HEV) different on-board energy sources; the proposed arrangement for the propulsion system includes fuel cell (FC), ultra-capacitor (UC) tank, and battery unit system (BU). In terms of power sources, the proton exchange membrane fuel cells (FCs) are being increasingly accepted as the most appropriate supply for electric vehicles (EVs) because they offer clean and efficient energy without penalizing performance or driving range. The FC generator, that is the main energy source, has poor efficiency at light load thus the BU is devoted to supply the power at such situation in order to save total efficiency. The UC tank is used to satisfy acceleration and regenerative braking requirements accomplishing the system load transients and improving the on-board BU life time. The paper is mainly focused on modeling the converter for both steady-state and dynamic behavior. Regulators tuning is also carried out, as well complete control system implementation on DSP board is accomplished. Information on carried on experimental test campaign are provided. Achieved results show power balancing appropriate to characteristics of generation and storage units.

47 citations


Proceedings ArticleDOI
04 May 2004
TL;DR: In this paper, the authors presented an efficient dynamical identification method to estimate parameters of a permanent magnet synchronous machine (PMSM) during different operating conditions using dynamical measurements.
Abstract: In advanced motor control system, an accurate knowledge of motor parameters is essential in order to achieve a good performance. Some of these parameters, such as stator resistance are given by constructors, but they vary in different operating conditions. The purpose of this paper is to present an efficient dynamical identification method to estimate parameters of a permanent magnet synchronous machine (PMSM). Using this method, we can determine these parameters during different operating conditions. This method has been simulated and implemented in an experimental test bench using a dSpace board and obtained results proved the validity and efficiency of proposed method. Physical parameters estimation of a dynamical 3-parameter model thanks to dynamical measurements is performed using an output error algorithm based on non linear optimisation. Simulations results show that, if PMSM is fed by a PWM inverter, no extra-signal, such as a pseudo random binary sequence (PRBS) adding on speed reference in vector control of PMSM, is necessary to excite the machine to assure identification algorithm convergence. However an extra-signal is a disturbance in respect to the machine running.

47 citations


Proceedings ArticleDOI
04 May 2004
TL;DR: In this article, the authors present an architecture allowing the operation of each separate photovoltaic module at his optimum, independently of other modules, and propose a structure which allows simultaneously to galvanically isolate the module from the grid, to increase the voltage, to convert DC current to AC current.
Abstract: The market for photovoltaic systems has considerably developed during the last few years, be it for grid-connected power generation or along the sun applications. However, the cost of solar modules remains a sensitive issue which entails the need for a better use of available power. In this paper, we present an architecture allowing the operation of each separate photovoltaic module at his optimum, independently of other modules. For this purpose, we consider the use of large number of small converters, each of them being associated to one photovoltaic module, instead of only one converter. To be economically feasible, we propose a structure which allows simultaneously to galvanically isolate the module from the grid, to increase the voltage, to convert DC current to AC current. The whole structure ensures that the power conversion is done with reduced losses. The converter structure is also designed for parallel operation with as many modules as necessary in order to obtain the desired power. It ensues that the dynamic response of a module must be carefully studied to avoid any unforeseen oscillation between two or more different converters or between a module and others loads distributed along the network.

42 citations


Proceedings ArticleDOI
04 May 2004
TL;DR: This paper tries to survey recent energy efficient MAC protocols for WSN and presents a classification of the various approaches pursued and several energy-efficient MAC protocols are described and discussed under the appropriate category.
Abstract: Recent advances in wireless sensor networks (WSN) have led to many new protocols specifically designed for different kinds of applications where energy efficiency is an essential consideration. Most of the attention, however, has been given to the medium access control (MAC) protocols since they pay an important role in wireless communications and traditional MAC protocols are not suitable for WSN. This paper tries to survey recent energy efficient MAC protocols for WSN and presents a classification of the various approaches pursued. The four main categories explored in this paper are scheduling based, collision free, contention based, and hybrid schemes. Several energy-efficient MAC protocols are described and discussed under the appropriate category. Moreover, requirements for the MAC layer in WSN are also discussed. The paper concludes with open research issues in the end.

42 citations


Proceedings ArticleDOI
04 May 2004
TL;DR: In this paper, the authors address the subject of fault diagnosis in boost converters, operating in continuous and in discontinuous mode, focusing particularly on the output filtering electrolytic capacitors.
Abstract: This paper addresses the subject of fault diagnosis in boost converters, operating in continuous and in discontinuous mode, focusing particularly, in the output filtering electrolytic capacitors. The failure of those capacitor's leads to an increase of their equivalent series resistance (ESR), and therefore, the efficiency decreases and the output voltage ripple increases. Two diagnostic methods are used, one is based on the relation between the mean values of the output voltage ripple and of the capacitor current ripple, both considered during the conduction time of the transistor, and the other is based on the relation between the value of the output voltage ripple for Ton/2 and the mean value of the output current. Several simulated and experimental results are presented for two DC-DC boost-type converters, one operating in the continuous mode and the other in the discontinuous mode.

Proceedings ArticleDOI
04 May 2004
TL;DR: In this paper, a simulation model of the VAL 206 traction system is developed by using the energetic macroscopic representation, in the electrical part, the various coupling are pointed out by this representation tool.
Abstract: A simulation model of the VAL 206 traction system is developed by using the energetic macroscopic representation, in the electrical part, the various coupling are pointed out by this representation tool. The global model is transposed into Matalab-Simulink/sup /spl trade// and simulations results are provided.

Proceedings ArticleDOI
04 May 2004
TL;DR: In this article, two frequency reconfigurable antennas using the ON/OFF states of a microelectromechanical system (MEMS) switch are presented, where an ON state RF MEMS switch, modeled by a piece of copper (1x1 mm/sup 2/), is inserted into the slot to achieve frequency switching.
Abstract: In this paper, two frequency reconfigurable antennas using the ON/OFF states of a microelectromechanical system (MEMS), are presented. A multifrequency planar inverted-F antenna (PIFA) is designed with a L-shaped open slot upon its main plate. As a proof-of-principle, an ON state RF MEMS switch, modeled by a piece of copper (1x1 mm/sup 2/), is inserted into the slot to achieve frequency switching (while OFF state is modeled without the piece of copper). According to the switch position alone the slot, the GSM operating frequency is not detuned while the other standards become reconfigurable. To validate our concept, a thermal MEMS switch, designed and developed at CEA-LETI is used. The MEMS switch is presented and its scattering parameters are measured and compared with simulated results from an equivalent RLC circuit. The active device is then inserted in the slot to valid the simulated frequency behaviour of the PIFA. Based on the same concept, a planar antenna is designed. It consists in a printed PIFA on a high-resistivity silicon substrate (10 k/spl Omega/.cm). The antenna resonates in the 2.4 GHz WLAN band but the insertion of two small gaps in its main aim which model the OFF state of a MEMS switch allows the antenna to work in the 5.150-5.875 GHz HIPERLAN 2 frequency bands.

Proceedings ArticleDOI
04 May 2004
TL;DR: From the experimental results of the level and temperature control, the fuzzy-PID controller has achieved and shown the better performance than standard PID controller E50AK, which is automatic tuneable parameter system.
Abstract: In this paper, a fuzzy proportional integral derivative (PID) controller, which is fabricated on a field programmable gate array (FPGA) is proposed to control an industrial process The fuzzy logic is provided to tune the PID parameters by using a gain scheduling method The tuning scheme is represented by a fuzzy system, which consists of fuzzification rule inference and defuzzification The fabricated FPGA chip, XC2S50-5tq-144, is embedded with the fuzzy system, which the chip is called fuzzy-PID controller The fuzzy-PID controller is contained several circuits, such as multiplier, adder, subtraction and some of the other logic gate The controller system uses two converter cards: TDA8763AM/3 (10 bits, high speed) to convert from analog to digital signal DAC08 (8 bits) to convert from digital to analog The maximum speed of the controller about 2,1 /spl mu/sec per action at 40550 MHz is calculated from timing summary The fuzzy-PID controller based on FPGA is verified by using to control model of level and temperature process From the experimental results of the level and temperature control, the fuzzy-PID controller has achieved and shown the better performance than standard PID controller E50AK which is automatic tuneable parameter system

Proceedings ArticleDOI
04 May 2004
TL;DR: An interpolation method is introduced to deal with the absence of marking due to, for instance, dirty marking, occlusion by other vehicles or poor visibility, and a KNN classifier recognizes the object from a training base built with simulated data.
Abstract: This paper describes a method of road segmentation and pattern recognition for road marking analysis. Efficient segmentation and pattern recognition are difficult due to other vehicles, outdoor lighting or shadows. Rectilinear marking and arrow extraction is carried out by mathematical morphology in order Io take into account geometrical characteristics (size for example). Thus, rectilinear objects such as white lines are extracted by Hough transform. We use Fourier descriptors to describe the boundaries of an object. Thus, a KNN classifier recognizes the object from a training base built with simulated data. Finally, the road is reconstructed with the elements detected in each image. Some results of the road segmentation and pattern recognition in difficult situations are shown. We introduce an interpolation method to deal with the absence of marking due to. for instance, dirty marking, occlusion by other vehicles or poor visibility.

Proceedings ArticleDOI
04 May 2004
TL;DR: In this paper, the simulation of a series HEV (hybrid electric vehicle) is suggested by using the energetic macroscopic representation (EMR) and simplified models are used in a first step.
Abstract: The simulation of a series HEV (hybrid electric vehicle) is suggested by using the energetic macroscopic representation (EMR). Simplified models are used in a first step. They lead to the simulation of an overall HEV with its control. The system is decomposed in two parts: the charge and traction subsystems. Simulations with Matlab-Simulink/sup /spl trade// are provided for the simplified system. These first simulations can now be improved by using more complex models of some devices. Indeed, the EMR organizes systems as interconnected components, that leads to modularity and flexibility.

Proceedings ArticleDOI
04 May 2004
TL;DR: In this paper, the authors provide an overview of the key components of by-wire systems, i.e., the electric actuators and the communication networks, especially for steering and braking operations.
Abstract: A significant innovation effort in ground vehicles' technology is represented by the replacement of the traditional mechanical-hydraulic systems with all-electric systems, termed by-wire systems, for the transmission and execution of the driving commands. According to the experience in the aerospace environment, such replacement is expected to give appreciable benefits, even though it poses several problems. This paper provides an overview of the key components of by-wire systems, i.e. the electric actuators and the communication networks, especially for steering and braking operations.

Proceedings ArticleDOI
Tae-Won Lee1, Sung-Ho Kim1, Yong-Ho Yoon1, Su-Jin Jang1, Chung-Yuen Won1 
04 May 2004
TL;DR: In this paper, a fuel cell simulator designed and manufactured as electrical characteristic of fuel cell generation system uses a simple buck converter to overcome the disadvantages of high-priced fuel cell system.
Abstract: Fuel cell system includes a fuel processor and subsystems Io manage air, water, thermal energy, and power. The overall system is high-priced and needs to peripheral devices. In this paper, the fuel cell simulator designed and manufactured as electrical characteristic of fuel cell generation system uses a simple buck converter to overcome these disadvantages. Characteristic of voltage and current (V-I) curve for fuel evil simulator is controlled by the linear function of being simplified, and we designed the fuel cell simulator. In addition, to verify fuel cell generation system performance and operation, full-bridge DC/DC converter and single-phase DC/AC inverter are designed and manufactured for fuel cell applications. The close agreement between the simulation and the experimental results confirms the validity and usefulness of the proposed fuel cell simulator.

Proceedings ArticleDOI
04 May 2004
TL;DR: In this article, a discrete time piecewise affine (PWA) model predictive control (MPC) strategy was used to design an explicit state feedback control law for the electronic throttle body.
Abstract: Electronic throttle body (ETB) is a car device that regulates air inflow into the motor's combustion system. Its performance has a major impact on the quality of the overall engine speed control. However, due to the usage of cheap components and some design features the ETB exhibits several nonlinear phenomena. This nonlinear behavior and the fact that there is only one measurement available - low quality measurement of the throttle position makes a design of the throttle controller a challenging task. Our approach is to model the ETB as a discrete time piecewise affine (PWA) system and apply model predictive control (MPC) strategy to design an explicit state feedback control law. Since MPC is a full-state controller and there is only one measurement available the rest of the states have to be estimated. We have chosen unscented Kalman filter (UKF) for the estimation purpose since it was performing the best in the presence of strong, almost discontinuous, process nonlinearities. In the end, MPC and UKF algorithm were implemented and tested on the real electronic throttle for the case of set-point reference. Experimental results indicate that the performance of cheaply produced components can be significantly improved with a good control strategy.

Proceedings ArticleDOI
04 May 2004
TL;DR: In this paper, a variable speed constant frequency (VSCF) system for aircraft applications is presented, which consists in a doubly fed induction generator supplying a stand-alone aircraft grid through its stator windings.
Abstract: This paper presents a variable speed constant frequency (VSCF) system for aircraft applications. More accurately, it focuses on the design of an output filter to reduce the influence of non-linear loads. The VSCF system consists in a doubly fed induction generator (DFIG) supplying a stand-alone aircraft grid through its stator windings. It uses back-to-back PWM converters connected to the rotor for sub and super synchronous speed operation. A permanent magnet synchronous machine (PMSM) connected to a variable speed prime mover supplies these converters. An efficient control strategy of the system was presented in a previous paper for linear loads. However, non-linear loads such as 6-pulse diode rectifiers, that can represent up to 50% of the total load introduce undesirable current harmonic components. A LC output filter is thus designed to eliminate them. Simulation results demonstrate the feasibility of the proposed system.

Proceedings ArticleDOI
04 May 2004
TL;DR: In this article, a comparison between a matrix converter and a back-to-back converter feeding a passive load is presented, with the aim of determining the converter topology which yields the highest output power per switches number.
Abstract: A comparison between a matrix converter and a back-to-back converter feeding a passive load is presented in this paper, with the aim of determining the converter topology which yields the highest output power per switches number. The comparison has been performed for different values of the output frequency. For each output frequency the load power has been increased until one of the switching devices reaches the maximum thermal stress, so defining the maximum output power of the converter. For this purpose, a simplified thermal model has been used to evaluate the junction temperature of the switches on the basis of the switch losses. An accurate computer model of both converters has been implemented taking into account the modulation laws and the real characteristics of the switching devices. Simulation results are presented showing the different behaviour of the two converters as a function of the output frequency. It has been verified that matrix converters perform better than back-to-back converters at low output frequencies.

Proceedings ArticleDOI
04 May 2004
TL;DR: In this article, the authors presented a fuzzy-logic approach to the energy management of an embedded fuel cell system, where two fuzzy controllers were proposed for both the internal air supply control loop and also for the whole embedded energy management strategy.
Abstract: This paper presents a fuzzy-logic approach to the energy management of an embedded fuel cell system. The main objective is to study one of the most technological bolts to be overcome for embedded fuel cell systems: their energy optimization. To reach this aim, experimentally validated models of a low power 5 kW proton exchange membrane fuel cell (PEMFC) and its most power hungry ancillary (the FC air supply system) are described. All simulation results have been performed using Matlab/Simulink/spl reg/ environment. Two fuzzy controllers are proposed for both the internal air supply control loop and also for the whole embedded energy management strategy.

Proceedings ArticleDOI
04 May 2004
TL;DR: In this article, a detailed analysis of the synchronized overmodulation control modes for standard voltage source inverters for adjustable speed ac drives is presented, and the linearity of the fundamental voltage during over-modulation is much better for the algebraic algorithms of synchronized pulsewidth modulation in comparison with the trigonometric ones.
Abstract: This paper presents detailed analysis of the synchronized overmodulation control modes for standard voltage source inverters for adjustable speed ac drives. Two basic versions of symmetrical discontinuous pulsewidth modulation (PWM) for control of inverters in the zone of overmodulation have been analyzed in the paper. It provides smooth shock-less pulses-ratio changing, and the spectra of the output voltage of inverters do not contain even harmonics and sub-harmonics (combined harmonics) in the overmodulation one, which is especially important for large drive systems. Simulations show, that linearity of the fundamental voltage during overmodulation is much better for the algebraic algorithms of synchronized pulsewidth modulation in comparison with the trigonometric ones.

Proceedings ArticleDOI
04 May 2004
TL;DR: In this article, a clamped-free beam equipped with collocated piezoelectric actuator/sensor is used to perform active damping of a flexible structure.
Abstract: A predictive control method to perform the active damping of a flexible structure is here presented The studied structure is a clamped-free beam equipped with collocated piezoelectric actuator/sensor Piezoelectric transducers advantages lie in their compactness and reliability, making them commonly used in aeronautic applications, context in which our study fits Theirs collocated placement allow the use of well-known control strategies with guaranteed stability First an analytical model of this equipped beam is given, using the Hamilton's principle and the Rayleigh-Ritz method After a review of the experimental setup (and notably of the piezoelectric transducers), two control laws are described The chosen one, generalized predictive control (GPC), is compared to a typical control law in the domain of flexible structures, the positive position feedback, one of the control law mentioned above Major befits of GPC lie in its robustness in front of model uncertainties and others disturbances The results given come from experiments on the structure which performed by a DSP GPC appears to suit for the considered study's context (ie damping of the first vibration mode) Some improvements may be reached Among them, a more complex structure with more than a single mode to damp, and more uncertainties may be considered

Proceedings ArticleDOI
04 May 2004
TL;DR: A field programmable gate array (FPGA) implementation of a bio-inspired visual sensor designed for estimating the optic flow onboard micro-air-vehicles (MAV) and improving the stabilization and visual guidance performances is described.
Abstract: Here we describe a field programmable gate array (FPGA) implementation of a bio-inspired visual sensor designed for estimating the optic flow onboard micro-air-vehicles (MAV) and improving the stabilization and visual guidance performances. Optic flow determination depends here on elementary motion detectors (EMDs), the principle of which was originally based on an electro-physiological analysis of the housefly's EMD neurons performed at our laboratory. FPGA technology appears to be well suited for use with several EMDs with visual fields covering various subregions of the MAVs fields of view. The multi-EMD architecture described here processes the signals emitted by a small linear array of photoreceptors operating in the current-integration mode. The experimental data presented confirm the validity of our multi-EMD implementation. The small 12/spl times/12 mm sized FPGA used here could incorporate up to 245 EMD.

Proceedings ArticleDOI
04 May 2004
TL;DR: The proposed hardware interface separates the hardware requirements from the real-time simulation requirements in terms of time resolution, maintaining appropriate accuracy in the testing procedure, and addresses the timing issues introduced by the presence of switching circuits in the system under test.
Abstract: Testing digital control systems for power electronics applications is an intricate procedure. An effective tool for the evaluation of electric systems and drives is provided by real-time hardware-in-the-loop (HIL) simulation, which is being increasingly used in industrial applications. However, to be practical, the real-time simulation platform must be inexpensive and easy to set up for various tests. In this paper, virtual test bed (VTB) and its real-time extension (RTVTB), in conjunction with a custom hardware interface, are utilized to implement an affordable and versatile real-time testing platform for digital controllers. The hardware interface addresses the timing issues introduced by the presence of switching circuits in the system under test. Integrating the switching gate control signal, which comes from the hardware digital controller, requires very high time resolution. However, such high resolution is not necessary to accurately simulate the electric system under control. The proposed hardware interface separates the hardware requirements from the real-time simulation requirements in terms of time resolution, maintaining appropriate accuracy in the testing procedure.

Proceedings ArticleDOI
04 May 2004
TL;DR: In this paper, the authors present a thermal model suitable for a MOSFET power switch derived from the seven-layer physical structure of the device, which can be implemented in real-time and used to estimate temperature variations within the active region of the power switch.
Abstract: Temperature management and control are among the most critical functions in power electronic devices, as operating temperature and thermal cycling can affect device performance and reliability. Therefore, it is useful to develop a device thermal model, which can be implemented in real-time and used to estimate temperature variations within the active region of the device. This paper begins by presenting a device thermal model suitable for a MOSFET power-switch derived from the seven-layer physical structure of the device. However it is shown subsequently that a third-order thermal model can give satisfactory estimates of device temperature. Furthermore, computational efficiency can he improved if the model is implemented as a third-order difference equation. Modelling results are compared with real-time temperature device measurements.

Proceedings ArticleDOI
04 May 2004
TL;DR: The paper presents a direct torque control DTC for induction motor drive using a 3-level NPC inverter optimized for torque oscillation reduction and evidencing the good performance validated by means of simulation.
Abstract: The paper presents a direct torque control DTC for induction motor drive using a 3-level NPC inverter. The control is optimized for torque oscillation reduction. The control is described evidencing the good performance validated by means of simulation. The results are reported and discussed in the paper.

Proceedings ArticleDOI
04 May 2004
TL;DR: In this article, a new switching amplifier circuit for multilayer actuators, which allows a fast and precise driving as well as the recovery of energy from the actuator, is presented.
Abstract: Today piezoelectric actuators are used in a growing number of applications. This article presents a new switching amplifier circuit for multilayer actuators, which allows a fast and precise driving as well as the recovery of energy from the actuator. Having modeled the power electronic analog circuit, its behavior could be well reproduced by a simulation. The design of a digital controller, which was considerably facilitated by this simulation, is presented. This controller and the analog switching amplifier as well as a model of the piezoelectric actuator are part of mixed analog digital simulation.

Proceedings ArticleDOI
04 May 2004
TL;DR: In this article, the authors describe the design and implementation of a computer controlled active load for characterization of the steady-state and the dynamic behaviors of polymer electrolyte membrane (PEM) fuel cell systems.
Abstract: This paper describes the design and implementation of a computer controlled active load for characterization of the steady-state and the dynamic behaviours of polymer electrolyte membrane (PEM) fuel cell systems. The active load converter is based on a linear regulator topology. The non-switching converter is ideal for steady-state measurements. The control of the converter is implemented in Simulink and dSpace and uses a PI feedback loop. The active load is designed for characterization of a fuel cell system, and therefore an electric circuit model for fuel cells is introduced. The circuit model contains a highly non-linear voltage source describing the activation polarization and the concentration polarization, two resistors for the ohmic polarization and the membranes double layer capacitor for the dynamic behaviour. The circuit model parameters are obtained from the measured data. Test results show good similarity with the fuel cell theory and confirm that the fuel cell circuit model can be used for modelling commercially available fuel cell systems, and uncontrolled fuel cell stacks.