high energy gain systems

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High-Gain Resonant Switched-Capacitor Cell-Based DC/DC Converter for Offshore Wind Energy Systems

High-Gain Resonant Switched-Capacitor Cell-Based DC/DC Converter for Offshore Wind Energy Systems

High voltage dc (HVDC) transmission promises a very flexible and efficient technology for offshore wind farms that requires power conversion systems to step-up and control the wind turbine output. A conventional HVDC system uses an ac line frequency (50/60 Hz) transformer to boost the voltage and ac/dc converters for rectification and power flow control. This technology is robust and reliable, but it causes a considerable increase in weight and volume, which leads to higher installation cost. A high-power density can be obtained by replacing the bulky 50/60- Hz transformers with high-frequency transformers. Unfortunately, high-frequency transformers with large turn ratios are difficult to design at high voltages and mega power levels because of the enormous expense of the magnetic material, core, and dialectic losses. One of the key-enabling components for HVDC is the high power dc/dc conversion system because it has a rigid structure, is easy to control system and more compact
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High Gain DC-DC Converter for Photovoltaic Systems

High Gain DC-DC Converter for Photovoltaic Systems

To improve the converging speed during the variation in solar irradiation level, load etc modified algorithms have been introduced. Lower dc voltages are obtained from the renewable energy sources such as solar panels, fuel cells etc. The grid connection of such resources is made possible by the electronic power inverters. Inverters are realized using a two stage power processing scheme which involves high step up dc dc front end converter followed by a grid tied dc-ac inverter. Since inverter stage requires high dc bus voltage, it may need to step up the low voltage of the solar panel tenfold or higher. Tapped inductor converters are an alternative which gives a simple circuit. The proposed converter is obtained from a basic SEPIC topology in order to attain higher voltage gain by the application of tapped inductor. The converter also has the advantage of continuous input current. Lower voltage ripple across the PV panel can be helpful in assisting the controller tracking the MPP with greater accuracy.
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Evaluating the performance of domestic solar thermal systems

Evaluating the performance of domestic solar thermal systems

Table 1 gives details of the solar systems, energy outputs and energy consumption over the two year monitoring period for ten properties with high occupancy levels. The property identification is given in col. 1. The solar energy output, recorded as described in Section 4, is given in col. 2. Two roof pitches were used in the design of the properties (27 and 40) and these are shown in col. 3. The monitoring duration for each property is given in col. 4 and varies slightly due to the inability to gain access to some properties on the date of the second anniversary of commissioning. The occupancy dates are given in col. 5 and relates to when at least one person was living in the property. The occupancy dates are converted to percentage occupancy in col. 6. For simplicity, the number and type of occupant is not considered, nor is the time of the year to which the occupancy relates. A more accurate calculation would prove to be very difficult since some properties are rented and the number and type of occupant can change on a regular basis. The cylinder hot water temperature from a typical winter's day in November/December 2008 are given in col. 7 and will be used to possibly explain differences in performance in Section 5.1. Gas and electricity consumption in kWh are given in cols. 8 and 9 respectively. The electricity consumption was taken from the calibrated household electricity meters in kWhs but units of gas consumed were recorded in m 3 from the calibrated household gas meters and converted to kWhs using a standard procedure as shown in Equation 1:
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PV Cell Fed High Voltage Gain DC-DC Converter for Grid Converter Applications

PV Cell Fed High Voltage Gain DC-DC Converter for Grid Converter Applications

Abstract- Low voltage photovoltaic systems require highly efficient converters to deliver as much as possible energy to the load with high gain DC voltage conversion. This concept presents two efficient step-up DC/DC converters one composed of five identical phases driven interchangeably and latter partial parallel isolated converter with voltage double. Experimental validation of theoretical assumption and discussion on power losses has been carried out. The use of silicon carbide components and current sharing technique assures high efficiency within wide power range. The proposed concept can be implemented to pv cell fed dc-dc converter for grid connected applications by using Matlab/Simulink software.
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Proposal of High Gain, Reduced Stress with Low Duty Cycle Two Input Boost Converter for Renewable Energy Systems

Proposal of High Gain, Reduced Stress with Low Duty Cycle Two Input Boost Converter for Renewable Energy Systems

D. Fourth Operation Mode: In this mode S1 is turned ON and S2 is turned ON, when output diode is blocked, DM2 conducts transferring part of the energy stored in the capacitor CM1 to the capacitor CM2 in re- sonant way. When there is a balance of energy between the multiplier capacitors, the diode DM2 is blocked (t4) also with low di/dt. During the switch turn on the input inductor stores some energy as the classical boost.

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A New Near Optimal High Gain Controller For The Non-Minimum Phase Affine Nonlinear Systems

A New Near Optimal High Gain Controller For The Non-Minimum Phase Affine Nonlinear Systems

High gain feedback has gained much interest in singular optimal control problems named cheap control [18-24]. [25] studied the cheap control of non-minimum phase nonlinear systems in the strict-feedback normal form defined in [26]. They used the HJB equation to solve the minimum energy problem for the internal dynamics of the systems with normal strictly feedback form. The internal dynamics in this class of systems is affine with respect to its single input y (the system’s output) as

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Interleaved DC DC Boost Converter with High Voltage Gain and Efficiency for Solar Energy Systems

Interleaved DC DC Boost Converter with High Voltage Gain and Efficiency for Solar Energy Systems

High Voltage Capacitor DC filter are necessary to produce the required smooth voltage waveform from Non uniform voltage sources. Large values of currents and ripples are removed by energy storing in the capacitors and expelling charges in a defined manner. High voltage capacitor filters makes use of capacitance reactance. A simple high pass filter circuit using inductors and capacitors are as in fig.7

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A Zvzcs Full Bridge Converter With High Voltage Gain By Solar Energy Source

A Zvzcs Full Bridge Converter With High Voltage Gain By Solar Energy Source

Recently, the demand for dc/dc converters with high voltage gain has increased because they are required as an interface system between the low voltage sources and the high voltage load which requires higher voltage. This high voltage gain dc to dc converter find applications in electric vehicles, uninterruptible power supplies, fuel cells, and photovoltaic systems [1]–[6]. A conventional boost converter is often used in step-up applications due to its simple structure and low cost. However, it is not suitable for high step-up applications. This is because the conventional boost converter requires an extreme duty cycle to obtain high-voltage gain and its voltage gain is limited due to its parasitic components [11]. The reverse-recovery problem of the output diodes is another important factor in dc/dc converters with high voltage gain. In order to remedy these problems, high step-up dc–dc converters using coupled inductors have been suggested in [9] and [10]. However, they have parasitic oscillations across the switches and diodes. The current-fed converters are often used in high step-up applications due to their inherent low input current ripple characteristic and high-voltage gain [8], [12] but here the voltage stresses of the switches are serious. In order to clamp the voltages across the switches and provide zero-voltage switching (ZVS) features, active snubbers are often employed. The snubbers require additional switches and cause additional conduction losses. As a result, the system efficiency decreases. To remedy these problems, many topologies have been proposed that is the voltage-fed converters such as phase-shift full-bridge (PSFB) converters, which are widely used, show low-voltage stress of the switching devices.
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Optimum Tilt Angle and Maximum Possible Solar Energy Gain at High Latitude Zone

Optimum Tilt Angle and Maximum Possible Solar Energy Gain at High Latitude Zone

Here it should be noted that even optimum orienting solar collector towards Equator could provide an increase in the produced power in relation to other orientations, a lower power production ratio compared with that produced by the tracking systems is envisaged especially during morning and evening. The effect of tilt angle and system orientation is evaluated theoretically and experimentally (Lazaroiu et al., [47]) on the basis of two photovoltaic systems: one fixed and one equipped with a sun tracker. The study verified that the PV module equipped with a single axis sun tracker evidenced an important
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Doubly Fed Induction Generator Based Wind Turbine Associated to a Shunt Active Power Filter for Current Harmonics Mitigation

Doubly Fed Induction Generator Based Wind Turbine Associated to a Shunt Active Power Filter for Current Harmonics Mitigation

Previous equations need to be modified in order to consider proper operation of the capacitor on the DC side of the inverter. The capacitor stores energy which is utilized as a power supply for the normal operation of the SAPF. More in detail, in normal operating conditions the SAPF does not feed active power because it should be able to supply p f = and q f = q l and so only reactive power is fed. For this reason, capacitor voltage level is

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workload placement within the different data centers trying to avoid job migrations among them that -as is mentioned by the authors- could lead to non-negligible system performance degradation. This approach considers the allocation of only one job per server. When the job is finished, the server sends a message to the scheduler indicating its status. Then the scheduler can assign a new job or deactivate it. This, in addition to the characteristic of awaking servers in advance, could be very beneficial to performance in scenarios where all the workloads had high computing demands. However, the energy savings in real cloud scenarios could be seriously affected because of the heterogeneity of workloads and the lack of mechanisms for handling heterogeneous hardware infrastructure. The allocation of jobs with low resource demands in complete servers could represent a serious resource waste problem.
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Analysis of Bent Ground plane on MIMO Antenna

Analysis of Bent Ground plane on MIMO Antenna

This paper presents the analysis of bent ground plane antennas for multiple-input-multiple-output (MIMO). Here, antenna array with three elements are proposed to evaluate the diversity performance of MIMO antennas systems. Then a three-element suspended plate antenna array with a bent ground plane is analyzed. The diversity performance of the design is analysed with the simulation results. At suspended angle α = 0 o , the reflection coefficient of antenna is found to be - 26.58 dB with an isolation of -47.53dB at resonance frequency 5 GHz. While At suspended angle α = 45 o , the reflection coefficient of antenna is found up to -29.69 dB with a maximum isolation of - 56.65dB.
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10.1 and 10.2 KMT and Pressure.ppt

10.1 and 10.2 KMT and Pressure.ppt

This means that although individual molecules may gain or lose kinetic energy, there is no net (overall) gain or loss of kinetic energy from these collisions.. There are no forces of a[r]

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A NOVEL High Step-Up Converter with a Voltage Multiplier Module for a Photo Voltaic System

A NOVEL High Step-Up Converter with a Voltage Multiplier Module for a Photo Voltaic System

A novel high step-up converter is proposed for a front end photovoltaic system. Through a voltage multiplier module, an asymmetrical interleaved high step-up converter usually high step up gain without act as a function at an extreme duty ratio. The voltage multiplier module is create of a conventional boost converter and coupled inductors. An extra conventional boost converter is combine into the first phase to achieve a considerably higher voltage conversion ratio. The two-phase configuration not only decreases the current stress through each power switch, but also force to do some thing the input current ripple, which decreases the conduction losses of metal–oxide– semiconductor field- effect transistors (MOSFETs). In addition, the proposed converter functions as an active clamp circuit, which moderate large voltage spikes across the power switches. Thus, the low-voltage-rated MOSFETs can be adopted for reduces of conduction losses
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Review on High Gain DC/DC converters for Renewable Energy Applications and their comparison with proposed converter

Review on High Gain DC/DC converters for Renewable Energy Applications and their comparison with proposed converter

playing a vital role in DC-back up energy system for UPS, grid system, high intensity discharge lamp and automobile applications also. In many applications, high-efficiency, high-voltage step-up dc–dc converters are required as an interface between the available low voltage sources and he output loads, which are operated at much higher voltages [2]. In order to provide high output voltage, the classical boost converters are used, but these should operate at extreme duty cycle. The conventional boost converter can be advantageous for step-up applications that do not demand very high voltage gain, mainly due to the resulting low conduction loss and design simplicity. Theoretically, the boost converter static gain tends to be infinite when duty cycle also tends to unity. However, in practical terms, such gain is limited by the loss in the boost inductor due to its intrinsic resistance, leading to the necessity of accurate and high-cost drive circuitry for the active switch, mainly because great variations in the duty cycle will affect the output voltage directly. Because of high gain, the rectifier diode must sustain a short pulse current with high amplitude [3]. This results in severe reverse recovery as well as high stress on switching devices. Using extreme duty cycle may also lead to poor dynamic responses to line and load variations. Moreover, the input current in these high step up applications is usually large, but low-voltage-rated MOSFETs with small R DS (ON) may not be selected since voltage rating of the
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Economics of renewable energy integration and energy storage via low load diesel application

Economics of renewable energy integration and energy storage via low load diesel application

In assessing the performance of the hybrid diesel systems, it is useful to define low (<30%), medium (30% to 60%) and high (>60%) RE penetrations. The level of RE penetration represents the renewable energy contribution, as a percentage of the total annual system load. Adopting this classification the reader can appreciate the divide between low RE penetration, where the majority of isolated power systems reside, and high RE penetration systems, those offering the lowest cost of energy (Figure 3. With reference to King Island, the configuration of the system from 2004 to 2012 approaches the cost optimized RE penetration level for a conventional diesel system (Figure 3a). Post 2012, enabling technologies, including a battery ESS, were installed on King Island. RE utilization increased to 65%, the cost optimized RE penetration level for diesel plus ESS (Figure 3a) [34]. In realizing high RE penetrations, King Island has addressed many technical barriers; however, commercial obstacles remain, with the system capital cost exceeding $20 million [35]. A significant contributor to this cost is ESS integration, yet without such enabling technologies, increasing the level of RE integration is not possible. The challenge for hybrid diesel systems seeking to emulate King Island remains to minimize the capital cost and complexity of such enablers. As an enabling technology, LLD achieves this. LLD performs as a conventional diesel system at low RE penetrations, while offering benefits comparable to ESS integration, at higher levels. LLD accordingly finds application bridging the two approaches, with the ability to offer many of the benefits of storage without the high capital cost or complexity. Conceptually it bridges the divide evident between low and high RE penetrations (Figure 3a), offering systems a transitional pathway to improved RE utilization. Such a strategy holds additional benefit as battery ESS pricing discounts over time.
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Modelling and Simulation of New Hybrid Boosting Converter for Photovoltaic System

Modelling and Simulation of New Hybrid Boosting Converter for Photovoltaic System

ABSTRACT: A hybrid boosting converter(HBC) having collective advantages of regulation competence from its boost structure and enhancement of the gain from its voltage multiplier structure is forthput in this paper. New converter incorporates a bipolar voltage multiplier, prominent symmetrical configuration, single inductor and single switch, high gain capability with wide regulation range, low component stress,small output ripple and obsequious extension, which make it suitable for front-end PV system and some other renewable energy applications. In the proposed work operation principle and voltage ripple are analysed. A 200-W 35V to 415V second order HBC prototype using open loop was designed. In proposed methodnew HBC with PI controller is designed.Thesimulation results assure the practicability of the converter.
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Semiconductor disk lasers: the future's bright; the colour's flexible

Semiconductor disk lasers: the future's bright; the colour's flexible

Laser Properties • High gain / short lifetime ns: similar threshold to doped-dielectric • Short lifetime ns: poor energy storage, poor qswitching • Broad gain bandwidth: 10-100nm tuning [r]

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OPTIMUM STOICHIOMETRY OF CADMIUM ZINC TELLURIDE THIN FILMS IN THE LIGHT OF OPTICAL, STRUCTURAL AND PHOTON GENERATED GAIN STUDIES

OPTIMUM STOICHIOMETRY OF CADMIUM ZINC TELLURIDE THIN FILMS IN THE LIGHT OF OPTICAL, STRUCTURAL AND PHOTON GENERATED GAIN STUDIES

CdTe and its associated materials suffer from ohmic contact problems because of their high electron affinity and consequently large work function. Author of the article [9] has reported the possibility of nickel as a contact material on CdTe through work function engineering. In this work Ni is chosen as the contact points on Cd 1-x Zn x Te thin films.

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Design and Analysis of High Step-Up Converter with a Voltage Multiplier Module for a Solar Photovoltaic System with Maximum Power Point Tracker

Design and Analysis of High Step-Up Converter with a Voltage Multiplier Module for a Solar Photovoltaic System with Maximum Power Point Tracker

output terminal. Meanwhile, the voltage stresses over the power switches are restricted and are much lower than the output voltage (380V). These switches, conducted to low voltage rated and low ON state resistance MOSFET can be selected. Furthermore, the full-load efficiency is 96.1% at Po = 1000 W, and the highest efficiency is 96.8% at Po = 400 W. Thus, the proposed converter is suitable for solar photovoltaic systems or other renewable energy applications like wind, fuel cell etc., that need high step-up high power energy conversion.

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