Showing papers by "Jean-Christophe Crebier published in 2011"

Optimized structure for next-to-next balancing of series-connected lithium-ion cells

Abstract: Voltage balancing between series-connected cells of rechargeable lithium-ion batteries is important for battery life, autonomy and security. Active balancing is the designated choice for applications that are sensitive to energy losses. A well-known next-to-next balancing technique is presented and its design and operating limitations are analyzed. This paper then presents a new technique for next-to-next balancing that improves on the conventional technique by offering better performances while being simpler to implement. Experimental results show an important reduction of the size of the magnetic coupler while maintaining efficiency at a level above 90%.

Design and Realization of Highly Integrated Isolated DC/DC Microconverter

Abstract: This paper deals with the design and the realization of an integrated isolated HF dc-to-dc converter for low-voltage and low-power conditioning applications (3.3 V and 1 W) including galvanic isolation. It is based on the 3-D integration of several elementary silicon dies in which essential components such as the inverter, the rectifier, the HF transformer, the input and output capacitors, and the output inductor have been integrated. The paper deals with the silicon integration of all these elements, with the presentation of our work being related with the state of the art. Then, it focuses on an estimate of the whole converter functional performance at 1-MHz switching frequency. Practical but partial implementation was carried out. The inverter and the rectifier are designed in CMOS technology (Austria Micro Systems 0.35 μm) and have been optimized to operate at HF (1 MHz) to reduce the size of passive devices. We have monolithically integrated all that is necessary for this function. The transformer, as well as the inductor and the capacitors, is also integrated on separate silicon dies. Their integration is discussed, as well as their design and practical characterization. Based on a distributed construction, the overall converter efficiency is estimated in simulation based on practical characterizations. It appears that correct efficiency with a reasonable silicon surface and volume can be reached.

Multi-cell battery emulator for advanced battery management system benchmarking

Abstract: This paper presents a hardware-in-the-loop battery simulation platform capable of emulating individual cells of a series connected string. The platform enables an efficient and reproducible way to benchmark battery management systems. The focus is put on battery modeling, embedded system architecture and software development. A practical implementation of a lithium-ion cell emulator based on a linear amplifier is described.

System for managing a series combination of electrical energy generation or storage elements, based on a plurality of voltage inverter legs

Abstract: A management system for managing a series association of elements for storing and/or generating electrical energy (CA 2 -CA n ), the system being characterized in that it comprises: first and second power bars (BP 1 , BP 2 ); a plurality of inverter arms (B 1 -B n-1 ) connected in parallel between said first and second power bars, each inverter arm being in turn constituted by two switches (T h1 , T b1 ) connected in series via a midpoint (PM 1 ) of the arm; a plurality of inductors (L 1 -L n ), each connected to the midpoint of a respective inverter arm; and a plurality of connectors for connecting the midpoint of each inverter arm to said series association between two adjacent elements via a respective one of said inductors. A series association of electrical energy storage and/or generator elements including such a management system.

Compact, isolated and simple to implement gate driver using high frequency transformer

Abstract: This paper presents a simple, ultra-compact and isolated gate driver system used to drive power switches. Using two legs of a CMOS inverter, a high frequency transformer and two zener diodes connected with the gate of power switch, this driver provides an optimal gate driver waveform with a high gate voltage to switch on the transistor, and a negative bias gate voltage during OFF state. In the paper, the proposed gate driver will be theoretically analyzed; simulation and experimental results for the system implemented to drive a high side MOSFET will be also showed and discussed.

Cascaded Inverters for electric vehicles: Towards a better management of traction chain from the battery to the motor?

Abstract: Currently small electric vehicles (EV) are generally implemented with low voltage batteries around 48V with high current in order to reach a power of several kW for the traction chain. The objective of future converters is to increase the AC amplitude to higher levels (up to 300V) in order to decrease the level of currents, while keeping the same transferred power. Voltage source inverters are generally used in order to drive electric motors. Multilevel voltage source inverters, namely cascaded H-bridge, are under investigation in this paper, in their application to electrical vehicles. This paper presents a numerical and experimental analysis of cascaded H-bridge inverters, and focuses on an optimal modulation strategy. The expected benefits of cascaded inverters for electric vehicle are a better management of battery cells, improved output voltage waveforms, spread thermal losses sources and a better operation in fault modes.

Integrated low power and high bandwidth optical isolator for monolithic power MOSFETs driver

Abstract: An integrated solution for the galvanic isolation between power transistors and their control unit is presented in this paper. This solution is based on a monolithic integration of a photodetector within a power MOSFET without any modification of its fabrication process. This photoreceiver can be associated with a monolithic driver to drive high side switches. Exhaustive characteristics for several integrated photodetectors are presented and discussed: quantum efficiency, step response, small signal analysis and sensitivity to the High Voltage MOSFET's Drain. The results of this analysis are photoreceivers with a Full Width at Half Maximum above 300MHz and a responsivity above 0.15A/W at a wavelength of 500nm. This leads to an integrated low power and high bandwidth optical isolation.

System for balancing, by magnetic coupling, an association in series of elements for generating or storing electrical energy

Abstract: The invention relates to a system for balancing an association in series of elements for generating and/or storing electrical energy, characterised in that it comprises: a plurality of full bridge inverters (OPC1, OPC2, OPCN), each consisting of two inverter arms connected in parallel between two end ports of the inverter, each inverter arm, in turn, consisting of two switches (Th1, Tb1; Th2, Tb2) connected in series by a so-called median point (P11, P12) of the arm; a plurality of connectors for connecting the two end ports of each full bridge inverter to a respective element (CA1, CA2, CAN, PV1, PV2, PVN) of said association in series; and a magnetic coupler (NM) formed by a magnetic core on which a plurality of windings (W^ W2, WN) is formed, each winding being connected to the median points of the arms of one of said inverters. The invention also relates to an association in series of elements (CA1, CA2, CAN) for the electrochemical storage of electrical energy, provided with such a balancing system. The invention further relates to an association in series of photovoltaic cells (PV1, PV2, PVN) provided with such a balancing system.

A new compact, isolated and integrated gate driver using high frequency transformer for interleaved Boost converter

Abstract: This paper deals with the design and the implementation of an integrated gate driver for interleaved converter. It is based on a novel gate driver topology for power switches like MOSFETs and IGBTs. Composed of two legs of a CMOS inverter, a high frequency pulse transformer and two Zener diodes connected with the gate of power switch, this driver topology provides an optimal bipolar gate driver waveform with greater positive and negative gate bias to switch ON and OFF. It represents a simple, ultra-compact, isolated gate driver. We have integrated several driver systems in CMOS technology (Austria Micro System 0.35 µm) in order to reduce power consumption, system size and to increase the robustness of gate driver. Therefore, this integrated driver circuit can be used for any multi-transistor applications. The operation principle of the proposed driver topology is detailed in this paper. The integrated gate driver is able to control a three phase interleaved Boost converter; the results show the effectiveness of the proposed driver system.

The vertical voltage termination technique — Characterizations of single die multiple 600V power devices

Abstract: Deep trench terminations are commonly known as a technique to achieve ideal breakdown voltages for high voltage devices. This paper presents the use of deep trench terminations as an original concept to integrate multiple vertical power devices on a common die. The concept is based on the creation of vertical deep trench terminations on the periphery of the devices, thus allowing to separate the drift regions and to completely insulate the multiple power devices sharing the same backside contact electrode. Power diodes in the range of 600V are fabricated and experimentally tested to validate the concept. The prototypes demonstrated excellent forward and reverse biased static characteristics.

Drift region integrated microchannel structure for direct cooling of power electronics

Abstract: Direct liquid microchannel cooling is of great interest when considering the thermal management of high heat flux power devices and modules. This paper presents an original concept for efficient cooling of power devices based on the integration of a microchannel cooler, including numerous parallel through wafer fluid vias, directly into the drift region of the power device and perpendicular to the PN junction. Simulation results proved that no negative side effects are resulting from this integration regarding the electrical performance of the device. Electrical tests were carried out to validate the functionality of the fabricated prototypes. The effectiveness of the proposed cooling technique was evaluated with hydraulic and thermal numerical models. In line with the device design and the microchannel cooler analysis an experimental setup for the measurement of the thermal and hydraulic performances of the concept was realized. Pressure drops were measured and compared with the theoretical results.

Electronic chip having channels through which a heat transport coolant can flow, electronic components and communication arm incorporating said chip

Abstract: The invention relates to an electronic chip, comprising: a semiconductor substrate (6) having an active area (8) formed by at least one P doped region and at least one N doped region which form one or more P-N junctions through which most of the useful current flows when said electronic chip is in a conductive state, and at least one channel (44) through which a heat transport coolant can flow, the channel(s) passing through at least said P or N doped region of the active area. Each channel (44) is rectilinear and passes through the substrate (6) in a direction which is collinear with a direction F to the nearest ± 45°, where the direction F is perpendicular to the plane of the substrate.

System for managing a series association of elements for generating or storing electrical energy based on a plurality of current-inverter arms

Abstract: System for managing a series association of elements for generating or storing electrical energy (CA 1 - CA N ), characterized in that it comprises: a first (B 1 ) and a second (B 2 ) power rail, which are connected together by way of an inductor (L) in series; a plurality of current-inverter arms connected between said first and second power rails, each of said arms being constituted by two bidirectional voltage switches (T G /D G ; T D /D D ) linked together in series by a point termed a midpoint (PM) of the arm; and a plurality of connectors for connecting each element of said series association between the midpoints of two said arms.

Innovative heat removal structure for power devices — The drift region integrated microchannel cooler

Abstract: Liquid microchannel cooling is approved to be a compact and high-performance solution to deal with the thermal requirements of power devices and modules. This is due to the large heat exchange surface, the high heat transfer coefficient and the minimized thermal interfaces that microchannel coolers offer. This paper reports an original concept for efficient thermal management of power devices based on the integration of a microchannel cooler, including numerous parallel through wafer fluid vias, directly into the drift region of the power device. Simulation results proved that no negative side effects are resulting from this integration regarding the electrical performance of the device. The effectiveness of the proposed cooling technique was evaluated with hydraulic and thermal numerical models. Vertical power diodes with integrated microchannel cooler were fabricated and characterized to demonstrate the feasibility and the effectiveness of the concept.

Optimization of a power mosfet and its monolithically integrated self-powering circuits

Abstract: The paper presents a physical structure optimizat ion of an integrated semiconductor device design: a power MOSFET and other vertical transistors are integrated within the same die, introducing a novel self supplied power transistor This integrat ed optimal design leads to complex optimization problems with close constraints The main constrain t deals with the avalanche phenomenon that is formulated by multiple integral expressions of nume rical functions The paper focuses on two aspects: the integral formulation of the avalanche model and mor e specifically its gradient computation in the view of applying a gradient-based optimization algorithm, a nd the comparisons of several optimization methods on this problem Keywords : Genetic optimization algorithms, gradient-based o ptimization algorithm, integration constraint, Power MOSFETs, design of monolithically integrated circuits

Quantification of Benefits and Drawbacks in Power Conversion Based on Complementary MOS Structures

Abstract: This paper deals with the advantages and drawbacks using complementary MOS structures in power converter. Approaching from the common-mode conducted electromagnetic interference (EMI) perspective, this paper shows, at first, how beneficial the complementary structures are. Experimental and simulation results underline the specific behavior of such structures. Then, other advantages and drawbacks are discussed and analyzed. This is made regarding the converter efficiency and the gate drivers operation for each converter leg. These issues are examined using simulations and experiments.

Towards reduced threshold voltages for vertical power Mosfet transistors

Abstract: The threshold voltage of insulated gate power transistors usually is around 3 to 4V and their nominal gate to source voltage between 15 and 20V. These unanimously recognized electrical characteristics are questioned in this paper in order to evaluate which benefits could be drawn from a reduction of the threshold voltage of power transistors. Logic level MOSFETs already exist, but this paper chooses to study theoretically the electrical and physical characteristics of power transistors as a function of the threshold voltage to see if these electrical values of power electronics standards are still appropriate. It appears that the reduction of the threshold voltage of power MOSFET reduces the amount of control power and may improve switching characteristics.

Système de gestion d'une association série d'éléments de génération ou de stockage d'énergie électrique basé sur une pluralité de bras d'onduleur de tension

Abstract: Systeme de gestion d'une association serie d'elements de stockage et/ou de generation d'energie electrique (CA1 - CAn), caracterise en ce qu'il comporte : une premiere (BP1) et une deuxieme (BP2) barres de puissance; - une pluralite de bras d'onduleur (B1 - Bn-1) connectes en parallele entre ladite premiere et ladite deuxieme barres de puissance, chaque bras d'onduleur etant a son tour constitue par deux interrupteurs (Th1, Tb1) connectes en serie par l'intermediaire d'un point dit point milieu (PM1) du bras; une pluralite d'inducteurs (L1 - Ln), relies chacun au point milieu d'un bras d'onduleur respectif; et une pluralite de connecteurs pour relier le point milieu de chaque bras d'onduleur a ladite association serie, entre deux elements adjacents, a travers un dit inducteur respectif. Association serie d'elements de stockage et/ou de generation d'energie electrique comportant un tel systeme de gestion.

Systeme d'equilibrage par couplage magnetique d'une association serie d'elements de generation ou de stockage d'energie electrique

Abstract: Systeme d'equilibrage d'une association serie d'elements de generation et/ou de stockage d'energie electrique, caracterise en ce qu'il comporte: une pluralite d'onduleurs en pont complet (OPC 1 , OPC 2 , OPCN), chacun desquels est constitue par deux bras d'onduleur connectes en parallele entre deux ports d'extremite de l'onduleur, chaque bras d'onduleur etant a son tour constitue par deux interrupteurs (T h1 , T b1 ; T h2 , T b2 ) connectes en serie par un point dit point milieu (P 11 , P 12 ) du bras; une pluralite de connecteurs pour connecter les deux ports d'extremite de chaque onduleur en pont complet a un element respectif (CA1, CA 2 , CA N , PV 1 , PV 2 , PV N ) de ladite association serie; et un coupleur magnetique (NM) forme par un noyau magnetique sur lequel est realisee une pluralite d'enroulements (W^ W2, WN), chacun desdits enroulements etant relie aux points milieux des bras de l'un desdits onduleurs. Association serie d'elements de stockage electrochimique d'energie electrique (CA 1 , CA 2 , CA N ) pourvue d'un tel systeme d'equilibrage. Association serie de cellules photovoltaiques (PV 1 , PV 2 , PV N ) pourvue d'un tel systeme d'equilibrage.

Modeling of power devices with Drift Region Integrated Microchannel Cooler

Abstract: This paper introduces the DRIMCooler — an innovative concept allowing to locate the heat exchanger directly inside the active region of a vertical power device. Based on vertical edge termination technique and the use of dielectric coolant fluid circulation, arrays of through wafer channels are drilled in the silicon substrate offering a large heat exchange coefficient while minimizing the pressure drops. The concept is introduced and discussed with respect to technological and electrical points of view. Thermal and fluidic issues are analyzed with numerical models and simulations. The obtained results show excellent thermal and hydraulic performances of the DRIM Cooler.