Search

We demonstrate the usefulness of RF magnetron sputtering ZnO thin film at softening temperature, as interfacial barrier layer in air stable flexible inverted organic photovoltaic devices. We investigate the influence of annealing on the ZnO crystallinity, on the ITO substrate morphology and charge transport at the ZnO/active layer interface. The photo-physical and structural characteristics of P3HT beside ZnO interfacial layer and the photovoltaic device performances were also studied using UV–vis spectroscopy, photoluminescence (PL) and J-V characteristic. Finally, we study the interfacial stability of devices with and without ZnO interfacial layer in both normal and inverted structure OPVs. We show that under optimized sputtering conditions, higher order and orientation structure of P3HT, the ZnO thermally annealed beside active layer offers better efficiency of contact between the active layer and interfacial layer. We also show that ZnO annealed at a softening temperature of 180 °C is functional for both photovoltaic devices (rigid and plastic substrates), leading to improved performance and stability of plastic solar cell devices.

Inverted polymer solar cells based on P3HT/PCBM bulk heterojunction were prepared on flexible polyethylene naphthalate (PEN) substrate. The effect of annealing of the PEN/ITO/ZnO multilayer and ZnO/P3HT:PCBM on the structural, morphological, photophysical and photovoltaic properties was investigated and scrutinized directly on the OPV devices using atom probe tomography (APT), scanning electron microscopy (SEM) and microfocus X-ray techniques. We carried out a 3D reconstruction of the interfaces of the multilayer containing PEN/ITO, ZnO/ITO and P3HT:PCBM/ZnO to address the interface micro-structure and its influence on the morphology of the photoactive film. The analyses show that the morphology of the interfaces is affected by the structure of each layer of the BHJ devices causing orientation of P3HT crystals with PCBM aggregates and ZnO, which in turn leads to a significant change of the charge transport across each layer and therefore photovoltaic performances.

The interfaces in multilayer inverted polymer solar cells based P3HT / PCBM bulk heterojunction were prepared and studied on a flexible polyethylene naphthalate (PEN) substrate. The annealing effect on each interface of the PEN/ITO/ZnO multilayer and also ZnO/P3HT:PCBM on the structural, photophysical and photovoltaic properties was investigated and scrutinized directly on OPV device using the tomographic atom probe (TAP), scanning electron microscope (SEM) and microfocus X-rays techniques. We carried out a three-dimensional reconstruction of each interfaces of the multilayer containing PEN / ITO, ZnO / ITO and P3HT: PCBM / ZnO to analyze interface property and its influence on the morphology of the photoactive film. These analyzes provide strong evidence that the morphology of the interfaces induced by the modification of the structure of each layer of the BHJ devices leading to an anisotropic morphology and good orientation of P3HT crystals with PCBM Aggregates and ZnO and thus to lead to a significant change of Characteristics of photovoltaic devices.

We report the formation of nanoimprint master templates that can be used for the fabrication of bit patterned media (BPM). The template was formed by directed self-assembly, with solvent annealing, of a symmetric ABA triblock copolymer to form perpendicularly oriented lamellae on chemical patterns. We used a high-χ block copolymer, poly(2-vinyl pyridine)-block-polystyrene-block-poly(2-vinyl pyridine) to achieve smaller feature sizes than are possible with polystyrene-block-poly(methyl methacrylate). The work shows that triblock copolymers can provide a large processing window in terms of pitch commensurability. Using block-selective infiltration (atomic layer deposition with sequential long soaking/purge cycles), an alumina composite with high etch resistance was specifically incorporated into the polar and hydrophilic P2VP domains. Subsequently, the surface pattern was successfully transferred into underlying Si substrates by etching with a fluorine-containing plasma to create a nanoimprint master. The line/space pattern of the nanoimprint master met the BPM fabrication requirement of defectivity

Directed self-assembly (DSA) of block copolymers (BCPs) is a leading strategy to pattern at sublithographic resolution in the technology roadmap for semiconductors and is the only known solution to fabricate nanoimprint templates for the production of bit pattern media. While great progress has been made to implement block copolymer lithography with features in the range of 10-20 nm, patterning solutions below 10 nm are still not mature. Many BCP systems self-assemble at this length scale, but challenges remain in simultaneously tuning the interfacial energy atop the film to control the orientation of BCP domains, designing materials, templates, and processes for ultra-high-density DSA, and establishing a robust pattern transfer strategy. Among the various solutions to achieve domains that are perpendicular to the substrate, solvent annealing is advantageous because it is a versatile method that can be applied to a diversity of materials. Here we report a DSA process based on chemical contrast templates and solvent annealing to fabricate 8 nm features on a 16 nm pitch. To make this possible, a number of innovations were brought in concert with a common platform: (1) assembling the BCP in the phase-separated, solvated state, (2) identifying a larger process window for solvated triblock vs diblock BCPs as a function of solvent volume fraction, (3) employing templates for sub-10-nm BCP systems accessible by lithography, and (4) integrating a robust pattern transfer strategy by vapor infiltration of organometallic precursors for selective metal oxide synthesis to prepare an inorganic hard mask.

In this paper, we report on the photovoltaic properties of conventional organic photovoltaic solar cells integrating a sputtered ZnO interfacial film deposited on the absorber P3HT:PCBM layer. An emphasis has been put on the influence of the annealing temperature and time for restoring and controlling the P3HT:PCBM/ZnO interface morphology, which can be damaged by the sputtering process. We show a significant improvement in the current-voltage (J-V) characteristics upon annealing up to 160 degrees C. This is evidenced by the reduction of the S-shape of these curves systematically observed for the cells integrating thick (100 nm) sputtered ZnO films. This approach was also highlighted on cells containing thinner (20 nm) ZnO films using a longer annealing process at 140 degrees C, which led to a significant improvement of the power conversion efficiency compared with the value recorded in as-prepared cells or in cells with no interfacial ZnO layer. These photovoltaic performances have been related to the change of the morphology of the absorber layer and to the vertical phase segregation of P3HT:PCBM at the interface with ZnO. Optical microscopy, scanning electron microscopy and atomic force microscopy have been performed in order to confirm this approach.

In this paper, the authors report about recent achievement in distributed Micro Electro Mechanical Systems (MEMS) behavioral modeling, allowing both easy development and faster simulation for better integration of arrayed MEMS into systems. Design and simulation are produced by solver-based cost-effective solution using VHDL-AMS. A hierarchical circuit-level design methodology has been followed to model and simulate a MEMS array-based smart surface applied in air–fluid environment for 2D contactless micromanipulation. Using a V-shaped-based design approach, a top-down VHDL-AMS-based modeling has been first achieved with behavioral, structural behavioral, and component models, which include a MEMS-based pneumatic microactuator. Then, a modeling bottom-up approach has been developed to validate our design by comparing simulations and experiments of the distributed surface. Good agreements of resulting simulations have been successfully provided at all abstraction levels proving capability and facility of using VHDL-AMS for coupled distributed physical models.

Bit Patterned Media (BPM) for magnetic recording provide a route to densities $>1 Tb/in^2$ and circumvents many of the challenges associated with conventional granular media technology. Instead of recording a bit on an ensemble of random grains, BPM uses an array of lithographically defined isolated magnetic islands, each of which stores one bit. Fabrication of BPM is viewed as the greatest challenge for its commercialization. In this article we describe a BPM fabrication method which combines e-beam lithography, directed self-assembly of block copolymers, self-aligned double patterning, nanoimprint lithography, and ion milling to generate BPM based on CoCrPt alloys. This combination of fabrication technologies achieves feature sizes of $, 44 pages

International audience; Cet article présente une stratégie complète d'identification et de commande d'un filtre actif parallèle améliorant les performances des systèmes classiques de dépollution des installations électriques. Basée sur des techniques neuromimétiques, notre approche s'adapte aux variations de charge du réseau et donc aux fluctuations des perturbations harmoniques. De plus, les réseaux neuromimétiques rendent la structure de calcul homogène pour une implémentation matérielle en temps-réel. Des simulations démontrent les caractéristiques originales de cette stratégie et des résultats expérimentaux permettent de valider la robustesse de l'approche.

This paper reports the design, fabrication and control of arrayed microelectromechanical systems (MEMS)-based actuators for distributed micromanipulation by generation and control of an air-flow force field. The authors present an original design of pneumatic microactuator, improving reliability and durability of a distributed planar micromanipulator described in the previous study. The fabrication process is based on silicon-on-insulator (SOI) wafer and HF (hydroflouric acid) vapor release, which also significantly increases the production yield of the 560 microactuator array device of 35times35 mm2. Minimization of the electrostatic actuation pull-in voltage through suspension shaping fabrication was also studied, and successfully validated for electrical efficiency improvement. A distributed control method to achieve good conveyance performance and reduce motion control instability was investigated. An emulation approach was chosen to validate a decentralized control strategy on the distributed active surface in order to conduct a proof-of-concept of a future smart structure, integrating sensors, intelligence, and microactuators. Thus, a centralized/decentralized control flow, inspired by autonomous mobile robot principles, was applied. It was modeled and implemented using C-programming language. Experimental and characterization results validate the control method for feedback micromanipulation with good velocity and load capacity performance

A technique for the self-alignment of components is applied to the assembly of a passive micro-valve which is to be used for safety purposes in a miniature fuel cell. The technique uses the capillary forces originating in the interactions of HMDS (Hexadimethyldisilazane) and the faces of the components to achieve their passive alignment. HMDS is chosen because it is a volatile, low surface tension and inert liquid. The originality of this method is that the liquid area is defined by the edges of the components. Compared to a traditional pick-and-place technique, it leads to a leakage rate more than five times smaller.

The impact of crystalline structure changes of sputtered ZnO interfacial layer on performances of inverted organic solar cells (OSCs) has been investigated. We find that the structural modification of the ZnO cathode interfacial layer, obtained by thermal annealing, plays a crucial role in the origin and solving of the S-curve in conjugated polymer/fullerene photovoltaics. Our results show that the crystallization (i.e. crystallites size) of poly(3hexylthiophene) (P3HT) evolves as a function of that of ZnO according to the annealing temperature. This evolution can directly impact the interfacial orientation and organization of the chains of P3HT at the ZnO buried interface. Such an ordered profile favors the vertical phase segregation and raises the carrier mobility, which explains the disappearance of the S-shape observed in current density-voltage device characteristics for annealing temperatures above 200 degrees C. These results adequately address recent research and provide an important insight into the interfacial layers of inverted OSCs. (C) 2014 Elsevier B.V. All rights reserved.

Zinc oxide (ZnO) has recently shown to be of considerable interest for the development of interfacial buffer layers in inverted organic solar cells (OSCs). High quality ZnO thin films can indeed be prepared on large-area ITO-coated flexible substrates, using low temperature deposition techniques such as sputtering, a compatible technique with roll-to-roll process. However, further studies are still needed for a better understanding of the influence of the flexible substrate properties on the photovoltaic performances of those devices. In this work, ZnO films have been sputtered on ITO-coated flexible (PEN) substrates and annealed at different temperatures. The role of the surface morphology and the crystalline quality of ZnO films has been investigated. In the window of flexible compatible process, we found that moderate annealing temperatures of ZnO (

Les auteurs de cet article presentent une structure de controle vectorielle de la machine asynchrone, proposant une alternative a la commande a flux rotorique orientee en reduisant l'influence des parametres propres a cette methode. Les principes du controle direct du couple sont introduit, de plus un module de simulation et un dispositif experimental sont proposes, permettant d'evaluer les possibilites de la structure. Finalement, les auteurs illustrent le bon fonctionnement du systeme, par une etude du comportement aux basses vitesses, ou l'influence de la resistance statorique peut etre critique

In this paper, we present latest results of a thermo-pneumatic microactuator based on polymer membrane and silicon technology. This device has application in distributed air-jet planar micromanipulation to levitate and convey small objects by changing air-flow direction on the surface. Our technology, combining deformable polymer membrane and movable silicon nozzle fabrication, offers many advantages compared to classic silicon technology, e.g. pneumatic microactuator array device. Those advantages are as follows: low-cost, reliable, simple batch fabrication process, multi-directional (4 directions) air-jet flow, low driving voltage (≤ 5 V), durability under high air-pressure, higher transparency for implementing photodetection capabilities, and enabling technology to use flexible and smart materials in MEMS.

In this work, we use rf magnetron sputtering to deposit at room temperature a ZnO thin film on top of a photoactive material based on P3HT:PCBM blend for organic photovoltaic devices. We investigate the influence of the sputtering conditions on the ZnO crystallinity, on the substrate layer nanoscale morphology and on the photovoltaic device performances. We show that, under appropriate sputtering conditions, the modification of the P3HT:PCBM film causes no functional damage of the photoactive layer, and leads to an improved performance of the photovoltaic devices.

In this work, we investigate in a Hardware-in-the-Loop (HiL) approach to solve the problems and opportunities created by the control of large numbers (hundreds to thousands) of MEMS sensors and actuators. Using HiL simulation, one or several devices of the system are used instead of their simulated models. HiL simulation is supposed to achieve a highly realistic simulation of equipment in an operational virtual environment. In this paper, we study the capacity of a FPGA component to compute a decentralized control strategy of a contact less micromanipulateur based on distributed pneumatique MEMS. We couple a VHDL-AMS behavioral model of the DMASM device with a FPGA-based real hardware element. To validate our approach, we are able to run the FPGA-based control algorithm by emulation from a simulated model of 5 × 5 cells. Simulation and hardware results are presented using a graphic interface with digital input and output nodes to perform the control emulation.

International audience; Distributed-air-jet MEMS-based systems have been proposed to manipulate small parts with high velocities and without any friction problems. The control of such distributed systems is very challenging and usual approaches for contact arrayed system don't produce satisfactory results. In this paper, we investigate reinforcement learning control approaches in order to position and convey an object. Reinforcement learning is a popular approach to find controllers that are tailored exactly to the system without any prior model. We show how to apply reinforcement learning in a decentralized perspective and in order to address the global-local trade-off. The simulation results demonstrate that the reinforcement learning method is a promising way to design control laws for such distributed systems.

International audience; In this paper, an efficient and reliable neural active power filter (APF) to estimate and compensate for harmonic distortions from an AC line is proposed. The proposed filter is completely based on Adaline neural networks which are organized in different independent blocks. We introduce a neural method based on Adalines for the online extraction of the voltage components to recover a balanced and equilibrated voltage system, and three different methods for harmonic filtering. These three methods efficiently separate the fundamental harmonic from the distortion harmonics of the measured currents. According to either the Instantaneous Power Theory or to the Fourier series analysis of the currents, each of these methods are based on a specific decomposition. The original decomposition of the currents or of the powers then allows defining the architecture and the inputs of Adaline neural networks. Different learning schemes are then used to control the inverter to inject elaborated reference currents in the power system. Results obtained by simulation and their real-time validation in experiments are presented to compare the compensation methods. By their learning capabilities, artificial neural networks are able to take into account time-varying parameters, and thus appreciably improve the performance of traditional compensating methods. The effectiveness of the algorithms is demonstrated in their application to harmonics compensation in power systems.

In this paper, we discuss a flip-chip packaging method using liquid solder for 3D large-scale electronic/MEMS co-integration. This approach has been inspired from self-assembly technique which is emerging as one of the main methods for fabrication of heterogeneous micro-and nano-systems. We proposed to form solder bump by coating liquid solder directly on electrodes of a MEMS chip based on sophisticate microstructures of electrostatic microactuator array. Self-alignment and assembly techniques for electronic receptor chip were also detailed in order to achieve efficient flip-chip of MEMS and Electronic chip without any stiction and contamination problem. Functionality of the system has been validated and perspectives discussed.

We report the transfer of sub-10 nm half-pitch grating patterns created through a combination of block copolymer directed self-assembly and sidewall spacer-based self-aligned double patterning into Si substrates. Low substrate bias reactive ion etching of TiOx conformally deposited onto carbon mandrels using atomic layer deposition renders distinct, pitch-halved spacers with minimal etch byproduct redeposition. Independent spacer and mandrel width control and the use of an underlying CrNx hard mask deposited by reactive sputtering facilitates etching of Si lines with low roughness and fine placement control. The insights into pattern transfer presented here are directly applicable to the fabrication of rectangular bit pattern nanoimprint templates at densities above 1.5 Td in(-2).

In this paper, a pneumatic conveyor and its control mode are proposed for tiny object manipulation. The conveyor consists of a 2D array of 560 air-nozzle actuators realized by the silicon MEMS technology. A distributed control method, based on local air-flow force application, has been developed and successfully validated. Experimental and characterization results are finally presented and analyzed.

In the present work, the authors were focused on control modes used in distributed microsystems. Especially, they studied distributed manipulation like motion active surface that have been an important topic in micro and nanofabrication field. After comparing advantages and drawbacks between centralized, decentralized and distributed control systems, they decided to apply the control mode to an airflow active surface based on pneumatic microactuator array, and fabricated by MEMS technology. The size of the device is about 35x35 mm 2 for 560 MEMS-based actuators and holes respectively at the front- and the back-side of the silicon substrate. In a first approach, and to overcome fabrication problems of the micro- smart system, combining electronic and electro mechanic elements, a co-design software/hardware solution was implemented. By this way, and using a digital image captured from a CCD camera, autonomy of the distributed microsystems could be developed. Afterward, a feedback control strategy was elaborated by applying principles of autonomous mobile robots that lend it to. A first prototype, validating all control mode principles was successfully implemented directly in software. Experiment results demonstrated advantages and good performances of the method.

In this paper, the authors proposed to study a model and a control strategy of a two-dimensional conveyance system based on the principles of the Autonomous Decentralized Microsystems (ADM). The microconveyance system is based on distributed cooperative MEMS actuators which can produce a force field onto the surface of the device to grip and move a micro-object. The modeling approach proposed here is based on a simple model of a microconveyance system which is represented by a 5 x 5 matrix of cells. Each cell is consisted of a microactuator, a microsensor, and a microprocessor to provide actuation, autonomy and decentralized intelligence to the cell. Thus, each cell is able to identify a micro-object crossing on it and to decide by oneself the appropriate control strategy to convey the micro-object to its destination target. The control strategy could be established through five simple decision rules that the cell itself has to respect at each calculate cycle time. Simulation and FPGA implementation results are given in the end of the paper in order to validate model and control approach of the microconveyance system.

In this paper, a design approach was proposed to define suitable structures of distributed controlled MEMS used in a pneumatic two-dimensional microconveyance system. After an introduction to distributed systems, a brief survey of their applications in the field of micromanipulation and prospect in industrial microfabrication was presented. Afterward, the authors introduced the notion of intelligent motion surface used in the field of pneumatic microconveyance. They analyzed suitable distributed structures based on elementary microconveyance, which are supposed to provide an appropriate air-flow force and overcome microfluidic problems. The first microconveyer prototype was fabricated by using bulk micromachining technique. It was developed to estimate MEMS density required to produce an elementary force to convey a micro-object. Then, a specific distributed structure was proposed to develop the pneumatic two-dimensional microconveyer device. The device size is 35 x 35 mm 2 for 560 MEMS-microvalves, controlled by distributed arrays and processed by a centralized intelligence via a microprocessor. From experimental conveyance results, we can conclude to the feasibility of the pneumatic microconveyance by distributed air-flow microactuators.

We developed a pneumatic conveyance system that consists of an array of micro air valves fabricated by MEMS technology. The array of 560 micro actuators successfully conveyed a small silicon chip, which was 3 mm/spl times/3 mm/spl times/100 /spl mu/m in size and 2 mg in weight. The chip was transferred to the force equilibrium point, which was generated by the arrayed actuators. In addition, we proposed a control method for the system; in this method, the equilibrium point is moved in order to transfer the object on it We also conveyed a small plastic chip, which was 5 mm /spl times/ 5 mm /spl times/ 1 mm in size and 38 mg in weight. In this case, efficient conveyance was achieved by detecting the object edge and applying tilted air jets to it. A full control of two-dimensional conveyance is under investigation. The control circuit chip was developed; the circuit is an array of cells that have optical sensors and processors. Distributed information processing by the cooperation of cells enabled detection of the shape of the conveyed object. Our future goal is to assemble the conveyance system with the circuit, and to realize the autonomous distributed micro conveyance system.

We propose a microconveyor based on silicon microelectromechanical systems (MEMS) technology and demonstrate successful operation of the microconveyor. Microactuators work as air nozzles, which generate directed air flow by changing the pathways of compressed nitrogen gas. One-dimensional conveyance of an object 2.1mm × 4.1mm × 200μm weighing approximately 4mg is demonstrated with a directed air flow of 17kPa. Using a two-dimensional conveyor, we levitate and move an object 3mm × 3mm × 100μm weighing approximately 2mg using a continuous air flow. Conveyance toward the force equilibrium point was achieved with a regularly pulsed air flow. We are now studying full control of two-dimensional conveyance. We also propose control by actuating air nozzles to change the direction of air flow and move the equilibrium point to transfer the object to the desired point.

This paper deals with the main perturbations such as voltage harmonic pollution, voltage unbalance and voltage sag in electrical systems. The series active conditioner is able to compensate these voltages on the customer side or on the sub-transmission side, leaving the fundamental voltage in the load terminals. Two control approaches (PI, RST) have been studied to ensure the regulation of the output voltage filter. An advanced RST corrector has been developed. Two methods of the disturbance identification have been proposed and compared. In this paper, through the simulations made by SABER numerical code, an energetic study is presented when the compensation of one or a combination of these voltages is aimed at. A power rating comparison has also been performed between the case with PLL and without PLL.

Block copolymer lithography, an alternative lithographic technique by which self-assembled patterns made from block copolymer thin films are used as lithographic masks, has achieved a high enough level of maturity to be considered for nanofabrication in magnetic recording bit patterned media and in some applications in the semiconductor industry. As the demand for lithographic dimensions squeezes into the single-digit nm scale, pairing block copolymer materials that segregate at these dimensions with adequate pattern transfer techniques is increasingly difficult. For example, PS-b-PMMA, the most mature block copolymer system can only form line/space patterns with pattern transfer above 10 nm. Other promising materials like P2VP-PS-P2VP triblocks, however, lack sufficient etch contrast for reactive ion etching. Here, we present a nanofabrication strategy that integrates atomic layer deposition, ALD, with block copolymer lithography to enable fabrication of sub-10nm features for high density magnetic storage. The selective, cyclic and self-terminating nature of the materials synthesis within ALD reactors provides powerful nanofabrication tools. In particular, two of these tools stand out as enablers for high density patterning: First, the chemical selectivity of the organometallic precursors has facilitated selective synthesis inside porous polymeric materials. Second, the conformality afforded by the self-terminating nature of the ALD reactions has proven to be ideally suited for feature doubling in self-aligned double patterning, SADP. Integrating these powerful tools with block copolymer lithography opens new possibilities in two fronts: On the one hand, it is possible to generate hybrid nanocomposites with nanometer-scale resolution and high etching contrast. This is particularly useful for high resolution block copolymer materials for which no natural etch contrast exists such as P2VP-PS-P2VP triblocks. On the other hand, it is possible to use the already sub-lithographic features obtained by standard PS-b-PMMA block copolymer lithography as the starting point for an additional density multiplication using spacer lines grown by ALD for SADP. Be it for selective infiltration synthesis in block copolymer patterns or for the precise conformal growth in nanostructures made from block copolymers, ALD is likely to emerge as an ideal complimentary technique to block copolymer self assembly to enable sub-10nm lithography.

This paper presents a general "top-down" methodology for design and simulation of system control ASIC (application specific integrated circuit) using hardware description languages (HDL). Two languages are used: VHDL (very high speed integrated circuit hardware description language) for ASIC modeling and realization, and SpectreHDL for analog modeling of the control environment. The different models allow the optimization step by step of the final ASIC from the optimization of the control algorithm to the ASIC architecture. Each stage is completed by a functional validation resulting of mixed (analog/digital) simulation. This methodology is applied to direct torque control (DTC) of an induction machine. After describing the DTC principle, algorithm validation and optimization are studied: choices of numerical calculation methods, binary format and type. Then, architecture optimization is developed in order to implement the algorithm. Due to torque regulation accuracy and reduced treatment time, optimized architecture using 32 bits fixed point specific format type has been hardware implemented.

Latest developments in digital intelligent motion, as digital signal processors (DSPs), has strongly improved AC motor control performances. Application-specific-integrated circuit (ASIC) technology has changed the need for rapid process and low-cost processor. However, new technological problems appeared, requiring digital properties which need considering, such as quantization, sampling, word length and data types. The authors of this paper propose to study the quantization problems on ASIC-based direct torque control of an induction machine. They present a high level behavior model of the specific circuit and analyze the torque quantization errors. Finally, simulation results illustrate quantization influences on control performances with different data type solutions.

The field oriented control of an induction motor is sensitive to machine parameters and some detuning is expected in most rotor flux oriented systems. Consequently, direct torque control has been introduced to reduce parameter sensitivity problems, which are negligible at high speed. The authors of this paper present principles and implementation, with a digital signal processor, of the control system. They propose solutions to correct integrators, which cause some drift and operation errors, and they estimate the possibilities of the proposal. They describe the methods used to obtain good performance, even in the low speed range, where the stator resistance influence becomes critical. >

Nowadays, industries are investigating new, original and appropriate solutions to address challenges in 3D MEMS-IC large-scale integration. Self-assembly techniques are among those. We report on an alternative approach inspired from fluidic self-assembly and using the flip-chip method. Here, solder bumps are directly formed onto a MEMS chip using liquid solder solution in a bath. The self-alignment process is operated after surface treatment by plasma deposition to form high and low wettability selective patterns. Finally, MEMS and electronic chips are permanently bonded after low thermal heating without any pressure. Electrical contact is established and electromechanisms of the microsystems are proven. Compared to classic MEMS-IC flip-chip methods, this strategy presents many advantages: it is a low-cost and fast fabrication process requiring no specific equipment for deposition of solder bumps. Furthermore, it can be applied on different substrates and it does not require a specific pressure method during the bonding process. This strategy is also an appropriate fabrication method for large-scale MEMS integration where electronic connection density is high.

An advanced common control method for shunt and series active conditioners, which compensate for the main types of disturbances in electrical power systems, is considered. If shunt and series actives conditioners are already well known as good compensation solutions for power quality improvement, it is also admitted that they generate some undesired components at switching frequency. To avoid these propagation problems, conditioner designers proposed a high-order output filter associated to a specific controller based on the RST control method. However, by applying this controller, it can be observed that a phase lag between the reference and the injected signal appears in the current and voltage control loop, which damages harmonic compensation. Therefore, a new RST controller is proposed, called RSTimp, to overcome the phase lag effects over the entire bandwidth for both active conditioners. The RSTimp proposed control method is validated through SABER simulations. These simulations show very good active conditioner performance in terms of rapidity, tracking and robustness for both current and voltage compensation.

The authors present a methodology for designing a CMOS very large scale integration (VLSI) controller for AC motor control. Step-by-step, top-down methodology based on hardware description languages (HDL) with mixed simulation was used to study digital adaptation and architecture implementation of the control algorithm. An application using the proposed methodology was studied: the direct torque control (DTC) of an AC motor. The DTC is described and VLSI examined. Analogue and digital models were used to describe the algorithm implementation, specific binary format and architecture. The register transfer level (RTL) model for the DTC controller was validated by mixed simulation. The ASIC layout was created using Austria Mikro System standard cell library for 0.8 μm CMOS. Finally, the authors compared this VLSI approach with software implementation and co-design methodology.