Showing papers on "Power module published in 2013"

Power module for use with a surgical instrument

Abstract: A surgical instrument, in at least one form, includes an end effector and a power module. The power module may include a first motion conversion assembly. The first motion conversion assembly includes a first rotary drive and a first axial drive operably coupled to the first rotary drive. The power module may further include a second motion conversion assembly which may include a second rotary drive and a second axial drive operably coupled to the second rotary drive. The power module may further include a motor configured to generate at least one rotational motion to actuate the end effector and a transmission assembly configured to selectively engage the motor with the first rotary drive and the second rotary drive, wherein the motor is concentrically arranged with the first rotary drive and the second rotary drive.

Systems and methods for wireless power transfer

Abstract: Systems and methods for enabling efficient wireless power transfer, and charging of devices and batteries, in a manner that allows freedom of placement of the devices or batteries in one or multiple (e.g., one, two or three) dimensions. In accordance with various embodiments, applications include inductive or magnetic charging and power, and wireless powering or charging of, e.g., mobile, electronic, electric, lighting, batteries, power tools, kitchen, military, medical or dental, industrial applications, vehicles, trains, or other devices or products. In accordance with various embodiments, the systems and methods can also be generally applied, e.g., to power supplies or other power sources or charging systems, such as systems for transfer of wireless power to a mobile, electronic or electric device, vehicle, or other product.

Apparatus and method for providing a modular power supply with multiple adjustable output voltages

Abstract: An apparatus and method for supplying operating voltages to a plurality of electronic devices is disclosed. A plurality of power supply modules of a modular power supply may output voltages to at least two electronic devices. The apparatus may identify a failure of one of the power supply modules. The electronic device may be disconnected from the failed power supply module, and then reconnected to a functional power supply module of the modular power supply. A supplied voltage of the functional power supply module of the modular power supply may be varied, such as wherein the supplied voltage matches the set output voltage of the failed power supply module.

High-Efficiency Wireless Power Transfer for Biomedical Implants by Optimal Resonant Load Transformation

Abstract: Wireless power transfer provides a safe and robust way for powering biomedical implants, where high efficiency is of great importance A new wireless power transfer technique using optimal resonant load transformation is presented with significantly improved efficiency at the cost of only one additional chip inductor component The optimal resonant load condition for the maximized power transfer efficiency is explained The proposed technique is implemented using printed spiral coils with discrete surface mount components at 1356 MHz power carrier frequency With an implantable coil having an area of 25 mm × 10 mm and a thickness of 05 mm, the power transfer efficiency of 58% is achieved in the tissue environment at 10-mm distance from the external coil Compared to previous works, the power efficiency is much higher and the structure is compact with planar integration, easy to tune, and suitable for batch production, as well as biocompatible owing to no incorporation of ferromagnetic core

An Energy-Stored Quasi-Z-Source Inverter for Application to Photovoltaic Power System

Abstract: The quasi-Z-source inverter (qZSI) with battery operation can balance the stochastic fluctuations of photovoltaic (PV) power injected to the grid/load, but its existing topology has a power limitation due to the wide range of discontinuous conduction mode during battery discharge. This paper proposes a new topology of the energy-stored qZSI to overcome this disadvantage. The operating characteristic of the proposed solution is analyzed in detail and compared to that of the existing topology. Two strategies are proposed with the related design principles to control the new energy-stored qZSI when applied to the PV power system. They can control the inverter output power, track the PV panel's maximum power point, and manage the battery power, simultaneously. The voltage boost and inversion, and energy storage are integrated in a single-stage inverter. An experimental prototype is built to test the proposed circuit and the two discussed control methods. The obtained results verify the theoretical analysis and prove the effectiveness of the proposed control of the inverter's input and output powers and battery power regardless of the charging or discharging situation. A real PV panel is used in the grid-tie test of the proposed energy-stored qZSI, which demonstrates three operational modes suitable for application in the PV power system.

In Situ Diagnostics and Prognostics of Wire Bonding Faults in IGBT Modules for Electric Vehicle Drives

Abstract: This paper presents a diagnostic and prognostic condition monitoring method for insulated-gate bipolar transistor (IGBT) power modules for use primarily in electric vehicle applications. The wire-bond-related failure, one of the most commonly observed packaging failures, is investigated by analytical and experimental methods using the on-state voltage drop as a failure indicator. A sophisticated test bench is developed to generate and apply the required current/power pulses to the device under test. The proposed method is capable of detecting small changes in the failure indicators of the IGBTs and freewheeling diodes and its effectiveness is validated experimentally. The novelty of the work lies in the accurate online testing capacity for diagnostics and prognostics of the power module with a focus on the wire bonding faults, by injecting external currents into the power unit during the idle time. Test results show that the IGBT may sustain a loss of half the bond wires before the impending fault becomes catastrophic. The measurement circuitry can be embedded in the IGBT drive circuits and the measurements can be performed in situ when the electric vehicle stops in stop-and-go, red light traffic conditions, or during routine servicing.

EV/PHEV Bidirectional Charger Assessment for V2G Reactive Power Operation

Abstract: This paper presents a summary of the available single-phase ac-dc topologies used for EV/PHEV, level-1 and -2 on-board charging and for providing reactive power support to the utility grid. It presents the design motives of single-phase on-board chargers in detail and makes a classification of the chargers based on their future vehicle-to-grid usage. The pros and cons of each different ac-dc topology are discussed to shed light on their suitability for reactive power support. This paper also presents and analyzes the differences between charging-only operation and capacitive reactive power operation that results in increased demand from the dc-link capacitor (more charge/discharge cycles and increased second harmonic ripple current). Moreover, battery state of charge is spared from losses during reactive power operation, but converter output power must be limited below its rated power rating to have the same stress on the dc-link capacitor.

Portable wireless charging pad

Abstract: The present disclosure provides a method and apparatus for improved wireless charging pads for charging and/or powering electronic devices. Such pads may not require a power chord for connecting to a main power supply, for example a wall outlet. In contrast, power may be delivered wireless to the foregoing pads through pocket-forming. A transmitter connected to a power source may deliver pockets of energy to the pads which through at least one embedded receiver may convert such pockets of energy to power. Lastly, the pads may power and/or charge electronic devices through suitable wireless power transmission techniques such as magnetic induction, electrodynamics induction or pocket-forming.

On a Future for Power Electronics

Abstract: This paper presents a historical and philosophical perspective on a possible future for power electronics. Technologies have specific life cycles that are driven by internal innovation, subsequently reaching maturity. Power electronics appears to be a much more complex case, functioning as an enabling technology spanning an enormous range of power levels, functions and applications. Power electronics is also divided into many constituent technologies. Till now, the development of power electronics has been driven chiefly by internal semiconductor technology and converter circuit technology, approaching maturity in its internally set metrics, such as efficiency. This paper examines critically the fundamental functions found in electronic energy processing, the constituent technologies comprising power electronics, and the power electronics technology space in light of the internal driving philosophy of power electronics and its historical development. It is finally concluded that, although approaching the limits of its internal metrics indicates internal maturity, the external constituent technologies of packaging, manufacturing, electromagnetic and physical impact, and converter control technology still present remarkable opportunities for development. As power electronics is an enabling technology, its development, together with internal developments, such as wide bandgap semiconductors, will be driven externally by applications in the future.

Use of Stored Energy in PMSG Rotor Inertia for Low-Voltage Ride-Through in Back-to-Back NPC Converter-Based Wind Power Systems

Abstract: The increasing installed wind power capacity has caused wind power generation to become a significant percentage of the entire electric power generation. As a consequence, the power system operators have included wind power plants regulation to improve the control of the overall power system, both in steady-state and transient operation. Therefore, wind power systems are required to verify the grid connection requirements stated by the power system operators. In presence of grid voltage dips, the low voltage ride-through (LVRT) requirement compliance produces a mismatch between the generated active power and the active power delivered to the grid. The conventional solution assumes that the active power surplus is dissipated in a dc-link resistor. In this paper, a control scheme for the back-to-back neutral-point-clamped converter is proposed. Under grid voltage dip, the controllers for generator-side and grid-side converters work concurrently to meet the LVRT requirement by storing the active power surplus in the turbine-generator mechanical system inertia while keeping constant the dc-link voltage. Simulation and experimental results verify the proposed control scheme.

Energy harvesting for a wireless-monitoring system of overhead high-voltage power lines

Abstract: For electric power transmission the overhead power line monitoring system plays an important role in operating security for grid operators as well as high supply availability at optimised cost. In this study, an approach to harvesting energy from the electric field around the conductor to supply the wireless sensor nodes was investigated. Special requirements in functionality, reliability and limited accessibility at the power line result in the development of a specific energy management strategy. A prototype of the power module was realised and tested under high voltage laboratory conditions. Then, a field test was carried out under real operating conditions. The test results confirm that the power module can collect enough energy to power the sensor nodes. The contribution in this study presents theoretical considerations of energy availability from the electric field, design of energy management and results from measurements with the prototype in a high voltage laboratory and in field test. The field test results demonstrate that the energy harvester can collect enough energy to power the sensor nodes by 16 mW.

Modeling and Simulation of All-Electric Ships With Low-Voltage DC Hybrid Power Systems

Abstract: DC hybrid power systems are of interest for future low emission, fuel-efficient vessels. In spite of the advantages they offer onboard a ship, they result in a complex, interconnected system, which requires effective analysis tools to enable a full realization of the advantages. Modeling and simulation are essential tools to facilitate design, analysis, and optimization of the system. This paper reviews modeling of hybrid electric ship components including mechanical and electrical elements. Power electronic converters are modeled by nonlinear averaging methods to suit system-level studies. A unified model for bidirectional converters is proposed to avoid transitions between two separate models. A simulation platform using the derived models is developed for the system-level analysis of hybrid electric ships. Simulation results of power sharing among two diesel generators, a fuel cell module, and an energy storage system are presented for three modes of operation.

Wireless power distribution system for military applications

Abstract: A wireless power distribution system for military applications is disclosed. The system includes a wireless power transmitter coupled with a power source. The transmitter may form pockets of energy using controlled radio frequencies. Electrical equipment coupled with an electronic receiver may utilize pockets of energy formed by the transmitter to charge or power the electrical equipment. The transmitter coupled with a power source may be used in a fixed position or may be carried in a vehicle for portability.

Comparison of Junction Temperature Evaluations in a Power IGBT Module Using an IR Camera and Three Thermosensitive Electrical Parameters

Abstract: The measurement of the junction temperature with thermosensitive electrical parameters (TSEPs) is largely used by electrical engineers or researchers, but the obtained temperature value is generally not verified by any referential information of the actual chip temperature distribution. In this paper, we propose to use infrared (IR) measurements in order to evaluate the relevance of three commonly used TSEPs with insulated gate bipolar transistor chips: the saturation voltage under a low current, the gate-emitter voltage, and the saturation current. TheIR measurements are presented in detail with an estimation of the emissivity of the black paint deposited on the power module. The temperatures obtained with IR measurements and with the different TSEPs are then compared in two cases: the use of only one chip and the use of two paralleled chips.

Energy harvest split core design elements for ease of installation, high performance, and long term reliability

Abstract: A power distribution monitoring system is provided that can include a number of features. The system can include a plurality of power line sensing devices configured to attach to individual conductors on a power grid distribution network. In some embodiments, the power line sensors can include a split-core transformer. In some embodiments, a power line sensing device is disposed on each conductor of a three-phase network. The sensing devices can be configured to measure and monitor, among other things, current and electric-field on the conductors. Methods of installing, sealing, and protecting the split-core transformers of the power line sensors are also discussed.

Power management for remote antenna units in distributed antenna systems

Abstract: Power management for a remote antenna unit(s) (RAUs) in a distributed antenna system. Power can be managed for an RAU configured to power modules and devices that may require more power to operate than power available to the RAU. For example, the RAU may be configured to include power-consuming RAU modules to provide distributed antenna system-related services. As another example, the RAU may be configured to provide power through powered ports in the RAU to external power-consuming devices. Depending on the configuration of the RAU, the power-consuming RAU modules and/or external power-consuming devices may demand more power than is available at the RAU. In this instance, the power available at the RAU can be distributed to the power-consuming modules and devices based on the priority of services desired to be provided by the RAU.

A Power Electronics Equalizer Application for Partially Shaded Photovoltaic Modules

Abstract: This paper studies a photovoltaic (PV)-module-embedded power-electronics topology derived from a battery equalizer. The proposed topology eliminates the multiple maximum power point peaks common to partial shading in PV modules. The topology does so by equalizing the overall energy of the PV module through the use of only one inductive storage element. A theoretical study is carried out to describe the physical equations of the topology. Based on it, a prototype is designed and built. It is tested with a partially shaded PV module, raising its power output by nearly 40% at best. The results are compared to similar topologies dedicated to mitigate partial shading in PV applications.

Energy Conversion and Transmission Modules for Space Solar Power

Abstract: This paper begins with an introduction to the concept of space solar power (SSP) and summarizes selected prior studies of proposed solar power satellite (SPS) systems. The functional components of a generic SPS are delineated, and various approaches and promising concepts from prior and current development efforts are elucidated. The fundamentals of wireless power transfer for the SPS application are reviewed, including a discussion of retrodirective beam control approaches. A survey of related technology research and development campaigns for energy conversion and transmission modules for recently proposed modular architectures is outlined. Advances in solid state amplifier technology with relevance to SSP are reviewed, with areas of particular criticality highlighted. Performance metrics for proposed SPS systems and their components are enumerated, and efforts to design, fabricate, and test a prototype conversion module operating at 2.45 GHz in a space-like environment are described.

Development of a SiC JFET-Based Six-Pack Power Module for a Fully Integrated Inverter

Abstract: In this paper, a fully integrated silicon carbide (SiC)-based six-pack power module is designed and developed. With 1200-V, 100-A module rating, each switching element is composed of four paralleled SiC junction gate field-effect transistors (JFETs) with two antiparallel SiC Schottky barrier diodes. The stability of the module assembly processes is confirmed with 1000 cycles of -40°C to +200°C thermal shock tests with 1.3°C/s temperature change. The static characteristics of the module are evaluated and the results show 55 mΩ on-state resistance of the phase leg at 200°C junction temperature. For switching performances, the experiments demonstrate that while utilizing a 650-V voltage and 60-A current, the module switching loss decreases as the junction temperature increases up to 150°C. The test setup over a large temperature range is also described. Meanwhile, the shoot-through influenced by the SiC JFET internal capacitance as well as package parasitic inductances are discussed. Additionally, a liquid cooled three-phase inverter with 22.9 cm × 22.4 cm × 7.1 cm volume and 3.53-kg weight, based on this power module, is designed and developed for electric vehicle and hybrid electric vehicle applications. A conversion efficiency of 98.5% is achieved at 10 kHz switching frequency at 5 kW output power. The inverter is evaluated with coolant temperature up to 95°C successfully.

Reactive Power Influence on the Thermal Cycling of Multi-MW Wind Power Inverter

Abstract: In this paper, the reactive power influence on the thermal cycling of power devices in grid-connected inverter for 10-MW wind turbines is investigated. Restrained by the grid codes, the allowable reactive power ranges in relation to amplitude and phase angle of the load current for a single converter system are first presented at different wind speeds. Furthermore, the interaction between paralleled converter systems in a wind park is also considered and analyzed. By controlling the reactive power circulated among paralleled converters, a new concept is then proposed to stabilize the thermal fluctuation of the power devices during wind gusts. It is concluded that the reactive power may change the thermal distribution of power devices. By properly controlling the reactive power, it is possible to achieve a more stable junction temperature in the power devices during the fluctuation of wind speed and thereby could provide a new way to improve the reliability of the wind power conversion system.

A Five-Level Single-Phase Grid-Connected Converter for Renewable Distributed Systems

Abstract: In low-power renewable systems, a single-phase grid-connected converter is usually adopted. This paper deals with a novel five-level converter topology that follows this trend. A review of the state of the art of the five-level topologies and a theoretical power loss comparison with the proposed solution is realized. The proposed converter architecture is based on a full-bridge topology with two additional power switches and two diodes connected to the midpoint of the dc link. Since the two added levels are obtained by the discharge of the two capacitors of the dc link, the balancing of the midpoint voltage is obtained with a specific pulse width modulation (PWM) strategy. Simulation and experimental results show the effectiveness of the proposed solution.

Active power control of photovoltaic power systems

Abstract: Historically, electric power system operators have seen photovoltaic (PV) power systems as potential sources of problems due to intermittency and lack of controllability. However, the flexibility of power electronic inverters allows PV to provide grid-friendly features including volt-VAR control, ramp-rate control, high-frequency power curtailment, and event ride-through. These technologies offer power quality improvements and enable wider penetrations of PV systems. Commercially available smart PV inverters can further provide frequency down-regulation by curtailing power, but they are unable to provide true frequency regulation through active power control (APC) because they are unable to increase power on command. The development of inverters capable of APC for primary and secondary frequency regulation without the need for energy storage has the potential to transform the way grid operators view high PV penetration levels. This paper provides a brief tutorial on APC of PV inverters, summarizes state of the art research in the area, and suggests future research directions.

Component cost models for multi-objective optimizations of switched-mode power converters

Abstract: Besides product differentiation, cost is a key parameter for market success and sustainable competitive advantage of industrial companies. Academic research in the field of power electronics, however, is often confined to the search for technical innovations or optimizations with focus on pure physical performance indices while the cost dimension is neglected. An explanation for the lack of such cost considerations is the generally poor availability of cost data in academia. This paper discusses the necessity of an increased awareness and sensitivity towards costs and the related opportunities for academic research. Furthermore, cost models for the power semiconductors, the passive components, the cooling systems and the printed circuit boards of switched-mode power converters with an approximate rated power between 5 and 50kW are derived. Based on manufacturer prices for large ordering quantities, numerical values for the cost model parameters are proposed. An example of a multi-objective comparison of different power converter topologies for photovoltaic applications regarding efficiency, volume and total semiconductor chip area is extended by the cost dimension to demonstrate the benefits of employing the developed cost models.

A High-Temperature SiC Three-Phase AC - DC Converter Design for > 100/spl deg/C Ambient Temperature

Abstract: High-temperature (HT) converters have gained importance in industrial applications where the converters operate in a harsh environment, such as in hybrid electrical vehicles, aviation, and deep-earth petroleum exploration. These environments require the converter to have not only HT semiconductor devices (made of SiC or GaN), but also reliable HT packaging, HT gate drives, and HT control electronics. This paper describes a detailed design process for an HT SiC three-phase PWM rectifier that can operate at ambient temperatures above 100°C. SiC HT planar structure packaging is designed for the main semiconductor devices, and an edge-triggered HT gate drive is also proposed to drive the designed power module. The system is designed to make use of available HT components, including the passive components, silicon-on-insulator chips, and auxiliary components. Finally, a 1.4 kW lab prototype is tested in a harsh environment for verification.

An active damper for stabilizing power electronics-based AC systems

Abstract: The mutual interactions between the parallel grid-connected converters coupled through the grid impedance tend to result in a number of stability and power quality challenges. To address them, this paper proposes an active damper concept based on a low-power, high-bandwidth power converter. The basic idea behind this proposal is to dynamically adjust the grid impedance seen from the point of common coupling of the grid-connected converters, such that the potential instabilities and resonance propagation can be effectively mitigated. Simulation and laboratory tests on three parallel grid-connected converters are carried out. The results validate the stabilizing performance of the active damper.

Control Strategy for Power Flow Management in a PV System Supplying DC Loads

Abstract: The growing concern for energy saving has increased the usage of LED-based street lights, electronic chokes, compact fluorescent lamps, and inverter-fed drives. Hence, the load profile seen by the electrical grid is undergoing a notable change as these devices have to operate from a dc source. Photovoltaics (PV) being a major energy source, the aforementioned loads can be connected directly to the dc bus. A grid-connected PV system involves a power source (PV array), a power sink (load), and two power sources/sink (utility and battery), and hence, a power flow management system is required to balance the power flow among these sources. One such system is developed for selecting the operating mode of the bidirectional converter by sensing the battery voltage. The viability of the scheme has been ascertained by performing experimental studies on a laboratory prototype. The control strategy is digitally implemented on an Altera Cyclone II Field Programmable Gate Array (FPGA) board, and the algorithm is verified for different modes of operation by varying the load. Experimental results are presented to bring out the usefulness of the control strategy.

A Low-Frequency Versatile Wireless Power Transfer Technology for Biomedical Implants

Abstract: Implantable biomedical sensors and actuators are highly desired in modern medicine. In many cases, the implant's electrical power source profoundly determines its overall size and performance. The inductively coupled coil pair operating at the radio-frequency (RF) has been the primary method for wirelessly delivering electrical power to implants for the last three decades. Recent designs significantly improve the power delivery efficiency by optimizing the operating frequency, coil size and coil distance. However, RF radiation hazard and tissue absorption are the concerns in the RF wireless power transfer technology (RF-WPTT) [4], [5]. Also, it requires an accurate impedance matching network that is sensitive to operating environments between the receiving coil and the load for efficient power delivery. In this paper, a novel low-frequency wireless power transfer technology (LF-WPTT) using rotating rare-earth permanent magnets is demonstrated. The LF-WPTT is able to deliver 2.967 W power at ~ 180 Hz to an 117.1 Ω resistor over 1 cm distance with 50% overall efficiency. Because of the low operating frequency, RF radiation hazard and tissue absorption are largely avoided, and the power delivery efficiency from the receiving coil to the load is independent of the operating environment. Also, there is little power loss observed in the LF-WPTT when the receiving coil is enclosed by non-magnetic implant-grade stainless steel.

Digital Detection, Control, and Distribution System for Co-Phase Traction Power Supply Application

Abstract: Unbalance and reactive power currents of electric railway will result in poor power quality of three-phase industrial power grid. A co-phase traction power supply system is introduced in this paper to solve these problems by adopting single-phase ac-dc-ac converter. The converter is connected between two secondary windings of traction transformer with abilities of active power transmission and reactive power compensation. Because of the power conversion, the co-phase supply system can utilize single-phase feeding connection scheme instead of traditional two-phase feeding scheme. An actual 10 MVA/27.5 kV co-phase system with impedance-matching balance transformer is designed, developed, and tested. Its real-time detection, control, and distribution algorithms with field programmable gate array-based implementation are introduced. Some test running results validate the performance of the digital controller and demonstrate the feasibility of the proposed co-phase power supply system.

A Compact and Integrated Multifunctional Power Electronic Interface for Plug-in Electric Vehicles

Abstract: The basic power electronic interfaces rendering volume and weight of electric and plug-in hybrid electric vehicles are an inverter, an on-board charger, and a bidirectional dc/dc converter. This paper proposes an innovative integrated bidirectional converter with a single-stage on-board charger to reduce the number of switches, size, and weight of the power electronic interfaces. The analyses show that 266 cm 3 and 1.1 kg can be saved due to the elimination of the inductor core used for power factor correction in charging mode, in addition to the reduction achieved through removal of inductor winding, power switches, diodes, and additional heat sink of the conventional structures. A proof-of-concept prototype with power limits of 8.4 kW in charging and 20 kW in propulsion modes has been designed and validated at various power levels. The peak efficiencies for propulsion and regenerative braking operations are measured as 96.6% and 94.1%, respectively. The power factor is recorded as 0.995 at 1.8 kW charging power, where crest factor and peak efficiency are recorded as 1.49 and 91.6%, respectively.

Control of grid-connected power converters based on a virtual admittance control loop

Abstract: The connection of electronic power converters to the electrical network is increasing mainly due to massive integration of renewable energy systems. However, the electrical dynamic performance of these converters does not match the behavior of the network, which is mainly formed by generation facilities based on big synchronous generation systems. Depending on the desired electrical operation mode different control structures can be implemented in the converters in order to get adapted with the grid conditions. However, changing between different control structures and operation is not an optimal solution, as the resulting system results complex and is not highly robust. As an alternative, this paper presents a new control technique for grid connected power converters based on the concept of virtual admittance. The proposed control permits to emulate the electrical performance of generation facilities based on classical synchronous generators with a power converter, with no need of implementing different control structures, giving rise to a system that provides a friendly and robust operation with the network.