Counter-Rotating Type Hydroelectric Unit (Effects of Blade Numbers on On-Cam Operations)

2011 ◽  
Author(s):  
Toshiaki Suzuki ◽  
Gohki Takano ◽  
Yoshihiro Nakamura ◽  
Toshiaki Kanemoto
Keyword(s):  
Maximum Efficiency ◽  
Maximum Output ◽  
Setting Angle ◽  
Hydroelectric Unit ◽  
Blade Setting Angles

To cope with warming global environments, authors have proposed the counter-rotating type hydroelectric unit, which is composed of tandem runners and the peculiar generator with double rotational armatures. The unit can be provided for various water circumstances at not only the onshore but also the offshore. This paper discusses effects of setting angle and the number of runner blades on turbine performances and then optimum blade setting angles giving the maximum output and/or the maximum efficiency, namely the on-cam operation, are presented at various discharges/heads.

scholarly journals Productivity Improvement by using Time Study Analysis and Modern Trends in Manufacturing Industry

2020 ◽  
Vol 4 (9) ◽  
pp. 75-79
Keyword(s):  
Material Handling ◽  
Manufacturing Industry ◽  
Manufacturing Sector ◽  
Maximum Efficiency ◽  
Maximum Output ◽  
Time Study ◽  
Work Study ◽  
Work Process ◽  
Productivity Improvement ◽  
Time Required

The productivity of any organization can be increased by optimizing the work process. Low productivity of workers is one of the reason behind the delay in delivery in manufacturing sector we know that in manufacturing sector labor is prominent thing. Improving the productivity means to make the best possible use of available resources and achieve maximum output. This paper focuses on the productivity of machine as well as labor by using fixtures, updated systematic layout and use of material handling equipment. This paper also covers the, what is productivity, which factors are affecting on productivity and efficiency. Maximum efficiency or productivity is trademark of any successful organization The objective of this paper is to identify the problem in medium scale industry due to time and effort required for any operations is high To tackle and understand a detailed analysis regarding processes using time study and work study. Due to implementation of all the measures the productivity of an organization is increases resulting in reduced effort and time required for operation and all operations done optimally.

Modeling and Simulation of MPPT-SEPIC Combined Bidirectional Control Inverse KY Converter Using ANFIS in Microgrid System

2016 ◽  
Vol 1 (2) ◽  
pp. 264 ◽  
Author(s):  
Soedibyo Soedibyo ◽  
Farid Dwi Murdianto ◽  
Suyanto Suyanto ◽  
Mochamad Ashari ◽  
Ontoseno Penangsang
Keyword(s):  
Energy Storage ◽  
Output Power ◽  
Distribution System ◽  
Maximum Output Power ◽  
Optimization Method ◽  
Photovoltaic System ◽  
Maximum Efficiency ◽  
Maximum Output ◽  
Pv System ◽  
Excess Power

<em>Photovoltaic system (PV) is widely used in various renewable energy application. The main problem of PV system is how to get the maximum output power which is integrated in microgrid system. Furthermore, the redundancy output power generated by on a distribution system should also be considered. This study utilizes the excess power for energy storage using bidirectional of KY inverse</em> <em>converter. Since the DC voltage which generated by PV and the energy storage will be converted into AC voltage using inverter toward load. This paper proposes ANFIS as search optimization method using SEPIC converter with a maximum efficiency of 99.95%</em> to impact to power generation performance  in microgrid system.

scholarly journals A Meta Study on the Implications of Thermoelectric Generation on Hybrid Photovoltaic Systems

2018 ◽  
Vol 5 ◽  
pp. 104-118
Author(s):  
Jamison Ghinis ◽  
Clifford Leslie
Keyword(s):  
Hybrid Systems ◽  
Considerable Effect ◽  
Operating Conditions ◽  
Energy Output ◽  
Maximum Efficiency ◽  
Practical Implementation ◽  
Total Efficiency ◽  
Maximum Output ◽  
Pv System ◽  
Specific Temperature

The focus of this paper is a meta-study analysis of the efficiency of hybrid thermal and photovoltaic (PV) energy systems and how various materials and specific temperature ranges for thermoelectric (TE) generation can increase their efficiency. This meta-study focuses on papers obtained from ACS NANO, Scopus, Web of Science and Nature which discuss the theoretical and practical implementation of TE and PV systems, with various hybrid systems being considered. Analysed is the Figure of Merit from various hybrid TE and PV integrated systems, the effect of energy efficiency and power generation on different PV system temperatures, and output over area. The total efficiency of the hybrid system is found to have a considerable effect in all papers analysed, with an increase of 5 to 10 percent efficiency in energy output due to the thermoelectric generator (TEG) section, with this maximum efficiency occurring approximately in a 25 kelvin range [1]. A maximum output of 125 W peaks can be maintained for systems efficiently over 600 W/m2 modules, this is an up to 5 percent total efficiency increase in power output in the previously discussed 25 kelvin range [2]. The papers proposed demonstrate the more efficient implementations, potential for further study and implementation of hybrid systems within specific temperature and operating conditions.

scholarly journals Extended Bandwidth and Increased Efficiency Quasi-Doherty Power Amplifier Design With A Revised Approach For Load Modulation

2021 ◽  
Author(s):  
Seyedehmarzieh Rouhani ◽  
Kasra Rouhi ◽  
Adib Abrishamifar ◽  
Majid Tayarani
Keyword(s):  
Power Amplifier ◽  
High Power ◽  
Maximum Output Power ◽  
Input Power ◽  
Maximum Efficiency ◽  
Maximum Output ◽  
Power Added Efficiency ◽  
Active Feedback ◽  
Doherty Power Amplifier ◽  
Load Modulation

This paper presents an approach to power added efficiency (PAE) increase for Quasi-Doherty power amplifier (Q-DPA) design. For this aim, active feedback is utilized instead of a passive quarter wavelength transmission line (TL) usage, which is conventionally used in the DPA schematic. PAE increase can be done by applying an accurate load modulation to the main amplifier (PAmain), especially for technologies in which output impedance of the main power amplifier (Zout,main) considerably varies in both low and high power regions. Because such precise modulation is still based on a modified TL, this approach suffers from the inherent narrowband behavior of that TL. As a consequence, expecting a wideband DPA may not be satisfied in all cases. To deal with this issue, active feedback is used to play a role in reaching PAmain, which is not saturated before, to its maximum efficiency at the highest level of received input power (Pin) in the high power region. Following Zout,main trajectories in power and frequency sweeps simultaneously just by a passive TL are not needed anymore. Still, for the sake of preventing total PAE degradation due to the consummated power by the feedback path’s power amplifier (PAfeedback) should be limited, analytical confinement is provided in this work. A comparison is made between GaAs pHEMT 0.25um MMIC technology-based conventional DPA and the proposed revised approach based-DPA to verify the mentioned approach. The proposed PA shows maximum output power of 33.4 dBm, maximum PAE of 41.6, fractional bandwidth of 11%. The Q-DPA works with a maximum power gain of 24.16.

Efficiency and Optimal Loading of Contra-Rotating Marine Turbines

2011 ◽  
Author(s):  
Wei Xu ◽  
Spyros A. Kinnas
Keyword(s):  
Output Power ◽  
Maximum Output Power ◽  
Optimization Method ◽  
The Self ◽  
Maximum Efficiency ◽  
Maximum Output ◽  
Optimum Ratio ◽  
Line Model ◽  
Performance Effects ◽  
Lifting Line

In this paper, an optimization method is developed for determining the loading on each component, which leads to the maximum efficiency (i.e. maximum output power) of a contra-rotating turbine when subject to uniform inflow. The lifting line model is adopted and both the self-induced velocities and the interaction induced velocities between the front and the back components are included. The optimum ratio of rotational velocities for reducing the torque on support structures and the performance effects of the gap distance between two components are investigated. The optimum distance for two in-line turbines in a turbine farm is also analyzed.

A Dual-Mode High-Voltage High-Efficiency Peak-Current-Mode Asynchronous Buck Converter

2016 ◽  
Vol 25 (11) ◽  
pp. 1650136 ◽  
Author(s):  
Zhaohan Li ◽  
Yongcheng Ji ◽  
Shu Yang ◽  
Yuchun Chang
Keyword(s):  
High Voltage ◽  
High Efficiency ◽  
Load Condition ◽  
Reducing Power ◽  
Current Mode ◽  
Buck Converter ◽  
Maximum Efficiency ◽  
Maximum Output ◽  
Peak Current ◽  
Light Load

This paper proposes a high-voltage high-efficiency peak-current-mode asynchronous DC–DC step-down converter operating with dual operation modes. The asynchronous buck converter achieves higher efficiency in light load condition compared to synchronous buck converters. Furthermore, the proposed buck converter switches operation mode automatically from pulse-width modulation (PWM) mode to pulse-skipping mode (PSM). By reducing power MOS on-state resistance and optimizing rise/fall time of switches, the proposed buck converter also obtains high efficiency under heavy load condition. The maximum efficiency of the proposed buck converter is 92.9%, implemented with 0.35[Formula: see text][Formula: see text]m BCDMOS 2P3M process, and the total size is 1.1[Formula: see text] 1.2[Formula: see text]mm2. The input range and output range of the converter are 6–30 V, and ([Formula: see text]–3) V, respectively, with the maximum output current of 3 A. Moreover, its built-in current loop leads to good transient response characteristics. Therefore, it can be used widely in communication system and 12 V/24 V distributed power system.

Optimization of Kaplan Hydroturbine at Very Low Head With Rim-Driven Generator

2019 ◽  
Vol 141 (11) ◽  
Author(s):  
Ahmad I. Abbas ◽  
Ryoichi S. Amano ◽  
Mandana S. Saravani ◽  
Mohammad D. Qandil ◽  
Tomoki Sakamoto
Keyword(s):  
Power Output ◽  
Rotational Speed ◽  
Maximum Output Power ◽  
Maximum Efficiency ◽  
Design Parameters ◽  
Maximum Output ◽  
Cfd Analysis ◽  
Original Design ◽  
Speed Range ◽  
Low Head

The objective of the paper is to study the design and optimization of Kaplan hydroturbines for a very low head (less than 3 m), with a particular emphasis on the use of rim-drive electrical generators. The work is based on an experimental setup and computational fluid dynamics (CFD) analysis of various design parameters for maximum output power and efficiency. Two designs are presented in this paper. One is a 90-cm (35-in.) diameter vertical-oriented Kaplan hydroturbine system as an intended product capable of generating over 50 kW. The other is a smaller, 7.6-cm (3-in.) diameter horizontal-oriented system for prototyping and laboratory verification. Both are analyzed through CFD based on large eddy simulation (LES) of transient turbulence. Specific design for the runner and the stator, intake tube shape, as well as guide vanes upstream of the turbine was studied to get the most from the available head. The intent is to use 3D-printing manufacturing techniques, which may offer original design opportunities as well as the possibility of turbine and water conduit design customization as a function of the head and flow available from a specific site. Based on the CFD analysis, the 7.6-cm diameter system achieved the highest power output and the maximum efficiency at the rotational speed range of 1500–2000 rpm, while for the experimental testing, the optimum rotational speed range was 1000–1500 rpm. Because of the mismatch between CFD and experimental results, the CFD results were correlated due to the presence of air and friction; moreover, error and uncertainty analysis were presented for both methods. For the 90-cm case, the optimum performance was found at a rotational speed around 350 rpm according to the CFD results. Finally, investigating the shape of the intake tube of the hydroturbine setup can significantly increase the power output and the efficiency of the system.

Optimal Control of a Hydrostatic Wind Turbine Drivetrain for Efficiency Improvements

2017 ◽  
Author(s):  
Majid Deldar ◽  
Sohel Anwar
Keyword(s):  
Optimal Control ◽  
Wind Speed ◽  
Wind Turbine ◽  
Wind Power ◽  
Minimum Principle ◽  
Maximum Output Power ◽  
Maximum Efficiency ◽  
Control Law ◽  
Maximum Output ◽  
Pontryagin Minimum Principle

To increase productivity of a wind power plant, the overall loss of its drivetrain should be minimized. For hydrostatic transmission wind turbine (HTSWT), aerodynamic efficiency of the rotor and the hydrostatic efficiency of pump and motor determine the overall loss. In this study, optimal control theory is utilized to develop a control law that minimizes the overall loss. A nonlinear model is considered for the drivetrain and a performance index (PI) is defined for the overall loss subject to system constraints which were then used to derive the optimal control law based on Pontryagin Minimum Principle (PMP),. Simulation results verified that the controller was able to maximize the drive-train efficiency. At very low wind speed, a trade-off is observed between aerodynamic and hydrostatic efficiency. For higher wind speed where the hydrostatic efficiency asymptotically reaches its maximum efficiency maximum output power coincided with maximum power point tracking of input wind power.

scholarly journals Adaptive On-Time Buck Converter with Wave Tracking Reference Control for Output Regulation Accuracy

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3809
Author(s):  
Pang-Jung Liu ◽  
Mao-Hui Kuo
Keyword(s):  
Output Voltage ◽  
Output Regulation ◽  
Buck Converter ◽  
Maximum Efficiency ◽  
Frequency Variation ◽  
Switching Frequency ◽  
Maximum Output ◽  
Equivalent Series Resistance ◽  
Load Current ◽  
Dc Offset

A ripple-based constant on-time (RBCOT) buck converter with a virtual inductor current ripple (VICR) control can relax the stability constraint of large equivalent series resistance (ESR) at an output capacitor, but output regulation accuracy deteriorates due to the issue with output DC offset. Thus, this paper proposes a wave tracking reference (WTR) control to improve converter stability with low ESR and concurrently eliminate output DC offset on the regulated output voltage. Moreover, an adaptive on-time (AOT) circuit is presented to suppress the switching frequency variation with load current changes in continuous conduction mode. A prototype chip was fabricated in 0.35 µm CMOS technology for validation. The measurement results demonstrate that the maximum output DC offset is 4.1 mV and the output voltage ripple is as small as 3 mV. Furthermore, the switching frequency variation with the AOT circuit is 11 kHz when load current changes from 50 mA to 500 mA, and the measured maximum efficiency is 90.9% for the maximum output power of 900 mW.

scholarly journals Design and simulate a doherty power amplifier using GaAs technology for telecommunication applications

2019 ◽  
Vol 15 (2) ◽  
pp. 845
Author(s):  
Ehsan Barmala
Keyword(s):  
Output Power ◽  
Power Amplifier ◽  
Power Amplifiers ◽  
High Efficiency ◽  
Maximum Output Power ◽  
Input Power ◽  
Power Divider ◽  
Maximum Efficiency ◽  
Maximum Output ◽  
Doherty Power Amplifier

<span>In this paper, a Doherty power amplifier was designed and simulated at 2.4 GHz central frequency which has high efficiency. A Doherty power amplifier is a way to increase the efficiency in the power amplifiers. OMMIC ED02AH technology and PHEMT transistors, which is made of gallium arsenide, have been used in this simulation. The Doherty power amplifier unique feature is its simple structure which is consisting of two parallel power amplifiers and transmission lines. In order to integrate the circuit, the Doherty power transmission amplifier lines were implemented using an inductor and capacitive components. Also, the Wilkinson power divider is used on the chip input. To improve the efficiency, the auxiliary amplifier dimensions is selected enlarge and the further input power is allocated it by the power divider. A parallel R-C circuit has been used at the input of transistors to improve their stability. Simulation results show that the Doherty power amplifier has 17.2 dB output power gain, 23 dBm maximum output power, and its output power P<sub>1dB</sub> =22.6dBm at compression point -1 dB, also, its maximum efficiency is 55.5%.</span>

Sign in / Sign up

Export Citation Format

Share Document