Showing papers on "Voltage published in 2008"

System and method for inductive charging of portable devices

Abstract: A system and method for variable power transfer in an inductive charging or power system. In accordance with an embodiment the system comprises a pad or similar base unit that contains a primary, which creates an alternating magnetic field. A receiver comprises a means for receiving the energy from the alternating magnetic field from the pad and transferring it to a mobile device, battery, or other device. In accordance with various embodiments, additional features can be incorporated into the system to provide greater power transfer efficiency, and to allow the system to be easily modified for applications that have different power requirements. These include variations in the material used to manufacture the primary and/or the receiver coils; modified circuit designs to be used on the primary and/or receiver side; and additional circuits and components that perform specialized tasks, such as mobile device or battery identification, and automatic voltage or power-setting for different devices or batteries.

Switched-Capacitor/Switched-Inductor Structures for Getting Transformerless Hybrid DC–DC PWM Converters

Abstract: A few simple switching structures, formed by either two capacitors and two-three diodes (C-switching), or two inductors and two-three diodes (L-switching) are proposed. These structures can be of two types: ldquostep-downrdquo and ldquostep-up.rdquo These blocks are inserted in classical converters: buck, boost, buck-boost, Cuk, Zeta, Sepic. The ldquostep-downrdquo C- or L-switching structures can be combined with the buck, buck-boost, Cuk, Zeta, Sepic converters in order to get a step-down function. When the active switch of the converter is on, the inductors in the L-switching blocks are charged in series or the capacitors in the C-switching blocks are discharged in parallel. When the active switch is off, the inductors in the L-switching blocks are discharged in parallel or the capacitors in the C-switching blocks are charged in series. The ldquostep-uprdquo C- or L-switching structures are combined with the boost, buck-boost, Cuk, Zeta, Sepic converters, to get a step-up function. The steady-state analysis of the new hybrid converters allows for determing their DC line-to-output voltage ratio. The gain formula shows that the hybrid converters are able to reduce/increase the line voltage more times than the original, classical converters. The proposed hybrid converters contain the same number of elements as the quadratic converters. Their performances (DC gain, voltage and current stresses on the active switch and diodes, currents through the inductors) are compared to those of the available quadratic converters. The superiority of the new, hybrid converters is mainly based on less energy in the magnetic field, leading to saving in the size and cost of the inductors, and less current stresses in the switching elements, leading to smaller conduction losses. Experimental results confirm the theoretical analysis.

Semiconductor apparatus and method of manufacturing the same

Abstract: PROBLEM TO BE SOLVED: To provide a MOS type semiconductor apparatus having a top gate structure capable of preventing excessive polishing and over polishing at the time of formation of a semiconductor crystal layer of a thin film in the top gate structure, of making thickness variation small to enhance gate characteristics, and of improving a gate withstand voltage. SOLUTION: In a MOS type semiconductor apparatus having a top gate structure, a p-type well region 120 is in a selective flat pattern in alignment with unit cells, and a polysilicon gate electrode 108 is in a flat pattern provided on the p-type well region 120 and on a substrate oxide film 104 positioned outside a first opening 103, and not provided on a region on which a semiconductor crystal layer 106 is laminated. COPYRIGHT: (C)2009,JPO&INPIT

Efficient Far-Field Radio Frequency Energy Harvesting for Passively Powered Sensor Networks

Abstract: An RF-DC power conversion system is designed to efficiently convert far-field RF energy to DC voltages at very low received power and voltages. Passive rectifier circuits are designed in a 0.25 mum CMOS technology using floating gate transistors as rectifying diodes. The 36-stage rectifier can rectify input voltages as low as 50 mV with a voltage gain of 6.4 and operates with received power as low as 5.5 muW(22.6 dBm). Optimized for far field, the circuit operates at a distance of 44 m from a 4 W EIRP source. The high voltage range achieved at low load current make it ideal for use in passively powered sensor networks.

An Isolated Three-Port Bidirectional DC-DC Converter With Decoupled Power Flow Management

Abstract: An isolated three-port bidirectional dc-dc converter composed of three full-bridge cells and a high-frequency transformer is proposed in this paper. Besides the phase shift control managing the power flow between the ports, utilization of the duty cycle control for optimizing the system behavior is discussed and the control laws ensuring the minimum overall system losses are studied. Furthermore, the dynamic analysis and associated control design are presented. A control-oriented converter model is developed and the Bode plots of the control-output transfer functions are given. A control strategy with the decoupled power flow management is implemented to obtain fast dynamic response. Finally, a 1.5 kW prototype has been built to verify all theoretical considerations. The proposed topology and control is particularly relevant to multiple voltage electrical systems in hybrid electric vehicles and renewable energy generation systems.

Model for Power Cycling lifetime of IGBT Modules - various factors influencing lifetime

Abstract: A large number of power cycling data from different IGBT module generations and test conditions have been evaluated. Multiple regression with respect to the variables temperature swing DeltaTJ, TJ, power-on-time (ton), chip thickness, bonding technology, diameter (D) of bonding wire, current per wire bond (I) and package type was performed. It provided parameters for a new empirical model describing number of power cycles (Nf) in relation to these variables. For a fixed module technology and blocking voltage class, the set of variables have been restricted to DeltaTJ, TJ, ton and I as the factors influencing the number of cycles to failure. The model is used to estimate the power cycling capability for the new generation of 1200V-IGBT4 Modules, which are rated up to a junction temperature of 150deg C in operation.

Double-Tiered Switched-Capacitor Battery Charge Equalization Technique

Abstract: The automobile industry is progressing toward hybrid, plug-in hybrid, and fully electric vehicles in their future car models. The energy storage unit is one of the most important blocks in the power train of future electric-drive vehicles. Batteries and/or ultracapacitors are the most prominent storage systems utilized so far. Hence, their reliability during the lifetime of the vehicle is of great importance. Charge equalization of series-connected batteries or ultracapacitors is essential due to the capacity imbalances stemming from manufacturing, ensuing driving environment, and operational usage. Double-tiered capacitive charge shuttling technique is introduced and applied to a battery system in order to balance the battery-cell voltages. Parameters in the system are varied, and their effects on the performance of the system are determined. Results are compared to a single-tiered approach. MATLAB simulation shows a substantial improvement in charge transport using the new topology. Experimental results verifying simulation are presented.

Vibration energy harvesting by magnetostrictive material

Abstract: A new class of vibration energy harvester based on magnetostrictive material (MsM), Metglas 2605SC, is designed, developed and tested. It contains two submodules: an MsM harvesting device and an energy harvesting circuit. Compared to piezoelectric materials, the Metglas 2605SC offers advantages including higher energy conversion efficiency, longer life cycles, lack of depolarization and higher flexibility to survive in strong ambient vibrations. To enhance the energy conversion efficiency and alleviate the need of a bias magnetic field, Metglas ribbons are transversely annealed by a strong magnetic field along their width direction. To analyze the MsM harvesting device a generalized electromechanical circuit model is derived from Hamilton’s principle in conjunction with the normal mode superposition method based on Euler‐Bernoulli beam theory. The MsM harvesting device is equivalent to an electromechanical gyrator in series with an inductor. In addition, the proposed model can be readily extended to a more practical case of a cantilever beam element with a tip mass. The energy harvesting circuit, which interfaces with a wireless sensor and accumulates the harvested energy into an ultracapacitor, is designed on a printed circuit board (PCB) with plane dimension 25 mm × 35 mm. It mainly consists of a voltage quadrupler, a 3 F ultracapacitor and a smart regulator. The output DC voltage from the PCB can be adjusted within 2.0‐5.5 V. In experiments, the maximum output power and power density on the resistor can reach 200 μW and 900 μ Wc m −3 , respectively, at a low frequency of 58 Hz. For a working prototype under a vibration with resonance frequency of 1.1 kHz and peak acceleration of 8.06 m s −2 (0.82 g), the average power and power density during charging the ultracapacitor can achieve 576 μ Wa nd 606 μ Wc m −3 , respectively, which compete favorably with piezoelectric vibration energy harvesters. (Some figures in this article are in colour only in the electronic version)

Design and New Control of DC/DC Converters to Share Energy Between Supercapacitors and Batteries in Hybrid Vehicles

Abstract: In this paper, the authors propose the supercapacitor integration strategy in a hybrid series vehicle. The designed vehicle is an experimental test bench developed at the laboratory of electrical engineering and systems (L2ES) in collaboration with the research in electrical engineering and electronics center of Belfort (CREEBEL). This test bench currently has two diesel motors (each connected to one alternator) and lead-acid batteries with a voltage rating of 540 V and a fluctuation margin between +12% and -20% of the rated voltage. The alternators are connected to the dc link by rectifiers. An original strategy of the supercapacitor integration in this vehicle with their control is presented to find a better compromise between the dimensions of the embarked devices, the share energy efficiency, the dynamics of the supply, and the electric power storage. The supercapacitor packs are made up of two modules of 108 cells each and present a maximum voltage of 270 V. The main objective is to provide a peak power of 216 kW over 20 s from supercapacitors to the dc link. Various topologies of dc/dc converters are presented with effective methodologies of electric power management in the hybrid vehicle.

Energy Scavenging From Low-Frequency Vibrations by Using Frequency Up-Conversion for Wireless Sensor Applications

Abstract: This paper presents an electromagnetic (EM) vibration-to-electrical power generator for wireless sensors, which can scavenge energy from low-frequency external vibrations. For most wireless applications, the ambient vibration is generally at very low frequencies (1-100 Hz), and traditional scavenging techniques cannot generate enough energy for proper operation. The reported generator up-converts low-frequency environmental vibrations to a higher frequency through a mechanical frequency up-converter using a magnet, and hence provides more efficient energy conversion at low frequencies. Power is generated by means of EM induction using a magnet and coils on top of resonating cantilever beams. The proposed approach has been demonstrated using a macroscale version, which provides 170 nW maximum power and 6 mV maximum voltage. For the microelectromechanical systems (MEMS) version, the expected maximum power and maximum voltage from a single cantilever is 3.97 muW and 76 mV, respectively, in vacuum. Power level can be increased further by using series-connected cantilevers without increasing the overall generator area, which is 4 mm2. This system provides more than an order of magnitude better energy conversion for 10-100 Hz ambient vibration range, compared to a conventional large mass/coil system.

Operation, design and control of dual H-bridge-based isolated bidirectional DC-DC converter

Abstract: The operation, design and control of an isolated bidirectional DC - DC converter for hybrid electric vehicle energy management applications are discussed. Different operation modes and boundary conditions are distinguished by phase-shift angle and load conditions. The absolute and relative output voltage ripple was derived. The dead-band effect and safe operational area are further investigated. The relations between output power and leakage inductance and switching frequency are also presented. The proposed converter was simulated and a prototype was built and tested. Experiments on the converter's steady state and transient operations validated the design and simulation.

Power transmission control device, power transmission device, electronic instrument, and non-contact power transmission system

Abstract: A power transmission control device provided in a power transmission device of a non-contact power transmission system includes an amplitude detection circuit that detects amplitude information that relates to an induced voltage signal of a primary coil, an A/D conversion circuit that performs A/D conversion of the amplitude information, and a control circuit. The A/D conversion circuit performs A/D conversion of a detected voltage detected by the amplitude detection circuit at a conversion timing and determines digital data relating to a reference threshold voltage, the conversion timing being a timing after a given period has expired from a timing when the detected voltage has exceeded a provisional voltage. The control circuit performs at least one of data detection that detects data that has been transmitted from a power reception device by means of load modulation, foreign object detection, and detachment detection using the digital data relating to the reference threshold voltage.

LED Driver With Self-Adaptive Drive Voltage

Abstract: This paper presents an LED driver circuit consisting of multiple linear current regulators and a voltage preregulator with adaptive output voltage. In the proposed driver, the output voltage of the preregulator is always self-adjusted so that the voltage across the linear current regulator of the LED string with the highest voltage drop is kept at the minimum value that is required to maintain the desired string current. Because the linear current regulators in this driver operate with the minimum voltages, the driver efficiency is maximized. The performance of the proposed driver was experimentally verified on a four-string LED setup with eight white LEDs in each string. The measured efficiency improvement of the linear current regulators was approximately 15% compared to the corresponding implementation with a constant preregulator voltage.

Inductive powering surface for powering portable devices

Abstract: Systems and methods for an inductive powering surface for powering portable devices are described. In one aspect, a powering device includes the inductive powering surface. The inductive powering surface includes multiple primary coils, an impedance auto-match circuit and other control circuits. The impedance auto-match circuit selectively energizes the primary coils to transfer power via inductive coupling to the secondary coil(s) in a portable device. The impedance auto-match circuit is configured to detect voltage and current phase differences over caused by positioning of the portable device on the inductive powering surface. The impedance auto-match circuit calibrates a power factor of the inductive powering surface to transfer an objectively maximized power load via inductive coupling to the portable device.

A Family of Single-Switch PWM Converters With High Step-Up Conversion Ratio

Abstract: A new family of a single-switch three-diode dc-dc pulsewidth-modulated (PWM) converters operating at constant frequency and constant duty cycle is presented in this paper. The proposed converters are different from the conventional dc-dc step-up converters, and they posses higher voltage gain with small output voltage ripples. Other advantages of the proposed converters include lower voltage stress on the semiconductor devices, simple structure, and control. Moreover, the reduced voltage stress on the diodes allows using Schottky diodes for alleviating the reverse-recovery current problem, as well as decreasing the switching and conduction losses. The principle of operation, theoretical analysis, and experimental results of one prototype rated 40 W and operating at 94 kHz are provided in this paper to verify the performance of this new family of converters.

An Improved Control Strategy of Limiting the DC-Link Voltage Fluctuation for a Doubly Fed Induction Wind Generator

Abstract: The paper presents to develop a new control strategy of limiting the dc-link voltage fluctuation for a back-to-back pulsewidth modulation converter in a doubly fed induction generator (DFIG) for wind turbine systems. The reasons of dc-link voltage fluctuation are analyzed. An improved control strategy with the instantaneous rotor power feedback is proposed to limit the fluctuation range of the dc-link voltage. An experimental rig is set up to valid the proposed strategy, and the dynamic performances of the DFIG are compared with the traditional control method under a constant grid voltage. Furthermore, the capabilities of keeping the dc-link voltage stable are also compared in the ride-through control of DFIG during a three-phase grid fault, by using a developed 2 MW DFIG wind power system model. Both the experimental and simulation results have shown that the proposed control strategy is more effective, and the fluctuation of the dc-link voltage may be successfully limited in a small range under a constant grid voltage and a non-serious grid voltage dip.

Long-Lifetime Power Inverter for Photovoltaic AC Modules

Abstract: This paper presents a power inverter tailored for low-power photovoltaic (PV) systems. The inverter features high reliability, thanks to a circuit topology that obviates aluminum electrolytic capacitors from the circuit. Moreover, all components, including logic and control, have been designed to exhibit high reliability at high temperatures. Three conversion stages form the power topology. First, a full bridge connected to a high-frequency transformer and a full-bridge rectifier amplifies the voltage of the PV panel to approximately 475 V. This stage is controlled by using a phase-shift pulsewidth-modulation controller that permits zero-voltage switching, thereby minimizing losses. Second, a buck converter is connected in series with the rectifier and is controlled by using current mode in order to shape the current injection into a rectified sine wave. Last, a full bridge is operated at line frequency to unfold the current injection. The amplification stage has a proportional compensator that maintains the voltage at the PV terminals constant. The current injection stage has a proportional-derivative compensator that controls the amplitude of the grid current so that the dc-link average voltage is maintained constant. Experimental results show that the peak efficiency of the system is 89%, and the total current harmonic distortion is below 5%. Finally, analyses show a designed lifetime of approximately ten years.

Distribution System Voltage Performance Analysis for High-Penetration PV

Abstract: Distributed generation can have an impact on distribution feeder voltage regulation, and distributed solar photovoltaics (PV) are no exception As the penetration level of solar PV rises over the coming decades, reverse power flow on the distribution feeder will happen more frequently and the associated voltage rise might lead to violations of voltage boundaries defined by ANSI C841 The severity of possible voltage problems depends on the relative size and location of distributed PV generation and loads, distribution feeder topology, and method of voltage regulation In this paper, an illustrative distribution system feeder is assumed, and various case studies are conducted The performance of the commonly used distribution voltage regulation methods under reverse power flow are investigated and presented Voltage performance of the feeder, and the flow of active and reactive power are studied under different loading assumptions, and different assumptions of PV inverters' participation The paper also explores the system performance using coordinated controls of inverters and utility equipment

An optimized self-powered switching circuit for non-linear energy harvesting with low voltage output

Abstract: Harvesting energy from environmental sources has been of particular interest these last few years. Microgenerators that can power electronic systems are a solution for the conception of autonomous, wireless devices. They allow the removal of bulky and costly wiring, as well as complex maintenance and environmental issues for battery-powered systems. In particular, using piezoelectric generators for converting vibrational energy to electrical energy is an intensively investigated field. In this domain, it has been shown that the harvested energy can be greatly improved by the use of an original non-linear treatment of the piezoelectric voltage called SSHI (Synchronized Switch Harvesting on Inductor), which consists in intermittently switching the piezoelectric element on a resonant electrical network for a very short time. However, the integration of miniaturized microgenerators with low voltage output (e.g. MEMS microgenerators) has not been widely studied. In the case of low voltage output, the losses introduced by voltage gaps of discrete components such as diodes or transistors can no longer be neglected. Therefore the purpose of this paper is to propose a model that takes into account such losses as well as a new architecture for the SSHI energy harvesting circuit that limits such losses in the harvesting process. While most of the study uses an externally powered microcontroller for the non-linear treatment, this circuit is fully self-powered, thus providing an enhanced autonomous microgenerator. In particular this circuit aims at limiting the effect of non-linear components with a voltage gap such as diodes. It is shown both theoretically and experimentally that the harvested power can be significantly increased using such a circuit. In particular, experimental measurements performed on a cantilever beam show that the circuit allows a 160% increase of the harvested power compared to a standard energy harvesting circuit, while the classical implementation of the SSHI shows an increase of only 100% of the output power in the classical case.

A 1.9μW 4.4fJ/Conversion-step 10b 1MS/s Charge-Redistribution ADC

Abstract: An ADC for energy scavenging is proposed using a charge-redistribution DAC, a dynamic 2-stage comparator, and a delay-line-based controller realized in CMOS. The charge-redistribution DAC can be used in a simple way to make a SAR ADC. The 10b differential ADC uses bootstrapped NMOS devices to sample the differential input voltage onto two identical charge-redistribution DACs. The test chip is fabricated in a 65nm CMOS process. In this ADC, the MSB is set in between the sampling phase and the first comparison, saving energy and time.

Virtual-Flux-Based Predictive Direct Power Control of AC/DC Converters With Online Inductance Estimation

Abstract: This paper presents an improved predictive direct power control (P-DPC) algorithm for grid-connected three-phase voltage source converters without AC-side voltage sensors. The new algorithm is based on virtual-flux (VF) estimation and operates with constant switching frequency. Predictive controller selects in every sampling period appropriate voltage vector sequence and calculates duty cycles in order to minimize instantaneous active and reactive power errors. The theoretical principles of this algorithm are discussed, and selected experimental measurements and scope graphs that illustrate the operation and performance of the system are presented. It is shown that VF-P-DPC algorithm exhibits several advantages, particularly sinusoidal-grid-current low harmonic distortion even when grid voltage is distorted. In addition, the algorithm provides high dynamics at low switching frequency of 2 kHz.

Modeling and Control of Six-Phase Symmetrical Induction Machine Under Fault Condition Due to Open Phases

Abstract: This paper introduces a new fault-tolerant operation method for a symmetrical six-phase induction machine (6PIM) when one or several phases are lost. A general decoupled model of the induction machine with up to three open phases is given. This model illustrates the existence of a pulsating torque when phases are opened. Then, a new control method reducing the pulsating torque and the motor losses is proposed in order to improve the drive performances. The proposed method is compared to two other existing techniques. The simulation and experimental results obtained on a dedicated test-rig confirm the validity and the efficiency of the proposed method for a fault-tolerant symmetrical 6PIM drive.

On the Efficiency of Voltage Source and Current Source Inverters for High-Power Drives

Abstract: The energy performance of various types of voltage-source and current-source converters is examined. For fairness and completeness, efficiency is calculated for three major battleground scenarios. The first is a low dynamic nonregenerative group of applications such as pumps, fans, and compressors. This group represents 85% of high power (2 MW) industrial applications where energy savings are usually a primary consideration justifying investment. The second scenario considers applications requiring good dynamic response and regenerative braking. Finally, the third group considers very high power applications (over 20 MW). The evaluation presented takes into account semiconductor switching and conduction losses, losses in the medium voltage feeding transformer (determined per IEEE Standard C57.18.10-1998), and the losses in ac and dc filters. For purposes of analysis, computer simulations validated against measurements taken on a 1-MW voltage source inverter (VSI) and a 1.4-MW current source inverter (CSI) were used. The results of the first scenario show competitive efficiencies for VSI and CSI drives, whereas voltage source-based solutions are more energy efficient in the second scenario considered. For the last group, the current source load-commutated inverter exhibits the best performance.

Lithium-ion battery state of charge estimation with a Kalman Filter based on a electrochemical model

Abstract: Lithium-ion battery is the core of new plug-in hybrid-electrical vehicles (PHEV) as well as considered in many 2nd generation hybrid electric vehicles (HEV). In most cases the lithium-ion battery performance plays an important role for the energy management of these vehicles as high-rate transient power source cycling around a relatively fixed state of charge (SOC). In this paper an averaged electrochemical Lithium-ion battery model suitable for estimation is presented. The model is based on an averaged approximated relationship between (i) the Butler-Volmer current and the solid concentration at the interface with the electrolyte and (ii) the battery current and voltage. A 4th order model based extended Kalman filter (EKF) is then designed and the estimation results are tested in simulation with the non-averaged model.

El display device

Abstract: An EL display device includes: a source driver circuit to output a video signal voltage; a gate driver circuit to select a pixel in a display screen; a first capacitor to maintain the video signal voltage; and a drive transistor to supply current to an EL element of a pixel. The video signal voltage is applied to the drive transistor to perform a predetermined operation, and written into the first capacitor. The video signal voltage maintained in the first capacitor is used to perform an offset cancel operation.

Battery Management System Based on Battery Nonlinear Dynamics Modeling

Abstract: This paper presents a method of determining electromotive force and battery internal resistance as time functions, which are depicted as functions of state of charge (SOC) because . The model is based on battery discharge and charge characteristics under different constant currents that are tested by a laboratory experiment. This paper further presents the method of determining the battery SOC according to a battery modeling result. The influence of temperature on battery performance is analyzed according to laboratory-tested data, and the theoretical background for calculating the SOC is obtained. The algorithm of battery SOC indication is depicted in detail. The algorithm of the battery SOC ldquoonlinerdquo indication considering the influence of temperature can be easily used in practice by a microprocessor. An NiMH battery is used in this paper to depict the modeling method. In fact, the method can also be used for different types of contemporary batteries, as well as Li-ion batteries, if the required test data are available.

Cell controller, battery module and power supply system

Abstract: A cell controller with excellent reliability in which noise and soon are suppressed is provided. The cell controller includes, corresponding to the number of cell packs, a plurality of ICs each having a voltage detecting circuit detecting voltages of respective cells of a cell pack in which four cells are connected in series, a switch control circuit controlling conduction and a blocking operation of a plurality of switch elements connected in parallel to the respective cells via capacity adjusting resistors, a LIN1 terminal for inputting control information, a LIN2 terminal for outputting control information, a Vcc terminal and a GND terminal, and a LIN2 terminal of a higher-order IC and a LIN1 terminal of a lower-order IC are connected in a daisy chain. The Vcc terminal of each IC is connected to a positive electrode of a higher-order cell among cells constituting a corresponding cell pack via an inductor L for eliminating noise, and the GND terminal is coupled directly to the Vcc terminal of the lower-order IC. Noise is not superposed on the LIN1, LIN2 terminals.

Hybrid single-electron transistor as a source of quantized electric current

Abstract: The basis of synchronous manipulation of individual electrons in solid-state devices was laid by the rise of single electronics about two decades ago1,2,3. Ultrasmall structures in a low-temperature environment form an ideal domain for addressing electrons one by one. In the so-called metrological triangle, voltage from the Josephson effect and resistance from the quantum Hall effect would be tested against current via Ohm’s law for a consistency check of the fundamental constants of nature, ℏ and e (ref. 4). Several attempts to create a metrological current source that would comply with the demanding criteria of extreme accuracy, high yield and implementation with not too many control parameters have been reported5,6,7,8,9,10,11. Here, we propose and prove the unexpected concept of a hybrid normal-metal–superconductor turnstile in the form of a one-island single-electron transistor with one gate, which demonstrates robust current plateaux at multiple levels of e f at frequency f.