Proposed System Configuration Research Articles

家庭用コンテナケース運搬ロボットにおける機械的柔軟性を活用したシステム構成法の提案と実証

This paper proposes a system configuration method to realize a robot system which can perform daily-use object storage and management service in a living space. In the method, compliant mechanisms are utilized proactively to overcome position/posture errors and deviations in measurement or control phases. To validate the proposed system configuration method, we developed a home-use container transfer robot that is installed with (1) robust container handling mechanisms implemented by crank shafts and (2) passive compliant mechanisms for horizontal and inclination misalignment. The robot was integrated with a container position measurement system to perform experiments. Experiments confirmed that a robust container transfer motion can be realized without complex feedback measurement and control processes. Several key design points are also described to leverage mechanical compliance.

A wind/diesel hybrid system with desalination for Star Island, NH: feasibility study results

This paper summarizes a feasibility study for a wind–diesel hybrid system for Star Island, New Hampshire, that also includes a desalination system component. In addition to supplying electricity during the peak demand summer months, this system attempted to balance the seasonal mismatch between wind resource and electric demand load via the production and storage of potable water during the winter months. A proposed system configuration featuring wind–diesel components as well as a desalination system was analytically modeled using hybrid power system computational codes. Both reverse osmosis and variable-power mechanical vapor compression desalination plants were modeled. Using specific data obtained from the site, these models calculated the electrical generation as well as the excess energy produced by the wind turbines that would be available to power a desalination plant. Energy produced, fuel savings, and water processed (and stored) were determined for a number of commercially available wind turbines. This work has shown that is economical to install two or three 7.5 kW wind turbines on Star Island without desalination, even considering that much of the energy would be wasted in the winter. The economics of a proposed desalination system were not determined to be favorable at the present time. The proposed system, however, was determined to be technically feasible and it offers some interesting system design and environmental advantages.

Hydrogen production from idle generation capacity of wind turbines

This paper is concerned with the hydrogen production from wind energy. It is motivated by the new regulations for wind farms that compel them to operate normally with idle generation capacity. The idea is to use the excess wind power to produce hydrogen. The operation of a proposed system configuration, which essentially consists in incorporating an electrolyzer between the electronic converters of a conventional wind turbine, is analyzed. In particular, the control requirements to simultaneously achieve the grid and electrolyzer specifications are investigated. In this context, a control strategy for the different operating modes of the system is developed.

Multilevel Diode-Clamped Converter for Photovoltaic Generators With Independent Voltage Control of Each Solar Array

In photovoltaic (PV) power systems where a set of series-connected PV arrays (PVAs) is connected to a conventional two-level inverter, the occurrence of partial shades and/or the mismatching of PVAs leads to a reduction of the power generated from its potential maximum. To overcome these problems, the connection of the PVAs to a multilevel diode-clamped converter is considered in this paper. A control and pulsewidth-modulation scheme is proposed, capable of independently controlling the operating voltage of each PVA. Compared to a conventional two-level inverter system, the proposed system configuration allows one to extract maximum power, to reduce the devices voltage rating (with the subsequent benefits in device-performance characteristics), to reduce the output-voltage distortion, and to increase the system efficiency. Simulation and experimental tests have been conducted with three PVAs connected to a four-level three-phase diode-clamped converter to verify the good performance of the proposed system configuration and control strategy.

Web performance engineering based on ontological languages and semantic web

We present a web system architecture using ontologies to improve the behaviour of the system from the performance viewpoint. Since web system performance indexes depend on state and parameter values on runtime period, the proposed system configuration will change during this period. In order to perform this change, the web system is monitored and gathered information stored into a knowledge base. We also model the performance of the different web system elements intervening in the configuration using the knowledge base expressed by means of ontologies. An example of the use of this ontology in cache tier is also presented. We propose the use of performance reasoners to change the configuration during runtime period based on the information supplied from the knowledge base.

Automatic flow system for sequential determination of ABTS [rad]+ scavenging capacity and Folin-Ciocalteu index: A comparative study in food products

In the present work, an automatic flow procedure for the sequential spectrophotometric determination of Folin-Ciocalteu reducing capacity (FC assay) and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS +) scavenging capacity expressed as the trolox equivalent (TEAC assay) is proposed for a comparative study of antioxidant properties in food products. Exploiting the flexibility of flow management associated to the computer control offered by multisyringe flow injection analysis, both methodologies were carried out in the same manifold using gallic acid and trolox as standard compounds. The proposed system configuration allowed the performance of each method separately or in tandem, providing 24 determinations per hour, which accounts for its application in routine analysis. The present methodology was applied to a large number of beverages ( n = 72), namely red and white wines, herbal and tea infusions, juices and beers. The results obtained showed that FC reducing capacity and TEAC values of red wines were significantly different from those obtained for the other beverages, while tea infusions provided significantly higher TEAC values when compared to white wines, herbal infusions, juices and beers. A good correlation was found between TEAC and FC reducing capacity ( R > 0.9) for red wines, herbal and tea infusions, and beers. For these beverages, similar slope values were found (106–140 mg L −1 of gallic acid per mM of Trolox), except for beers that showed a higher response for FC assay. These results provided evidence that the correlation between these assays vary according to the type of sample, reinforcing the idea that more than one method should be used for evaluation of antioxidant capacity.

A self‐commutated back‐to‐back system and its performance under a single line‐to‐ground fault condition

AbstractThis paper deals with a self‐commutated BTB (Back‐To‐Back) system for the purpose of power flow control and/or frequency change in transmission systems. Each BTB unit consists of two sets of 16 three‐phase voltage‐source converters, and their AC terminals are connected in series to each other via 16 three‐phase transformers. Hence, the BTB unit uses totally 192 switching devices capable of achieving gate commutation. This results in a great reduction of voltage and current harmonics without performing PWM control. Simulation results verify the validity of the proposed system configuration and control scheme not only under a normal operating condition but also under a single line‐to‐ground fault condition. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 143(3): 68–78, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10124

Performance of a self-commutated BTB HVDC link system under a single-line-to-ground fault condition

This paper deals with a self-commutated back-to-back (BTB) high-voltage direct-current (HVDC) link system for the purpose of power flow control and/or frequency change in transmission systems. Each BTB unit consists of two sets of 16 three-phase voltage-source converters, and their AC terminals are connected in series each other via 16 three-phase transformers. Hence, the BTB unit uses totally 192 switching devices capable of achieving gate commutation. This results in a great reduction of voltage and current harmonics without performing PWM control. Simulation results verify the validity of the proposed system configuration and control scheme not only under a normal operating condition but also under a single-line-to-ground fault condition.

A Self-Commutated BTB System and its Performance under a Single-Line-to-Ground Fault Condition

This paper deals with a self-commutated BTB (Back-To-Back) system for the purpose of power flow control and/or frequency change in transmission systems. Each BTB unit consists of two sets of 16 three-phase voltage-source converters, and their ac terminals are connected in series each other via 16 three-phase trans-formers. Hence, the BTB unit uses totally 192 switching devices capable of achieving gate commutation. This results in a great reduction of voltage and current harmonics without performing PWM control. Simulation results verify the validity of the proposed system configuration and control scheme not only under a normal operating condition but also under a single-line-to-ground fault condition.

Combining Activity-Based Costing with the Simulation of a Cellular Manufacturing System

Abstract Discrete-event simulation is one of the most effective techniques for analyzing a manufacturing system. Unfortunately, little attention is given to using simulation models to estimate the economic impact of a proposed system configuration. This paper defines how activity-based costing (ABC) concepts can be incorporated into a discrete-event simulation model. Special emphasis is on demonstrating how decision making can be aided by having the simulation create a detailed “Bill of Activity” describing costs associated with manufacturing a part. The integration of ABC and simulation is illustrated by evaluating the impact of a proposed manufacturing cell configuration. The additional costing information aids in cell design, determining part sequencing and scheduling, and provides a quick evaluation of product mix changes for a part family.

New high power, high performance power converter systems

A new, high performance, low cost power converter system architecture is proposed. The system consists of a main converter and a multifunctional load conditioner. The main converter deals with most of the power flow running at a low switching frequency. The load conditioner is designed at a much lower power level running at a high-switching frequency. The load conditioner can (1) act like a current source and inject harmonic currents required by the load; (2) act like an active resistor to provide damping to the main converter; and (3) for three-phase inverters, decouple the coupling sources in the main inverter model in the rotating coordinates to make the control loop design for the main inverter much easier. The concept has been proved by simulation and experimental results on a 150 kW high performance three-phase utility power supply prototype. The proposed system configuration can be used in high power DC-DC converters, inverters, PFC and UPS applications.

Satellite attitude stabilization through tether

Effective utilization of gravity gradient moments for attitude control demands rather slender satellite shapes. This imposes a major system design constraint and, further, provides only limited attitude accuracies, especially in the presence of disturbances and/or excitation. A new attitude control approach is presented here that overcomes most of these limitations. The proposed system configuration assumes a downward deployment of a ‘pendulum-like’ small mass from the satellite through a pair of identical tethers attached to its two distinct but symmetrically off-set points around the mass center. The well-known Lagrangian approach is utilized to obtain the governing equations of motion for the system in a circular orbit. A detailed stability analysis of motion-in-the-small is undertaken that establishes the feasibility of the concept. Furthermore, it leads to useful design criteria in the form of inequality constraints on the control parameters.

Electron discharge devices

A 100 kWe liquid-cooled HT-PEMFC subsystem is integrated with an absorption chiller subsystem to provide electricity and cooling. The system is designed, modeled and simulated to investigate the potential of this technology for future novel energy system applications. Liquid-cooling can provide better temperature control and is preferable for middle-scale transport applications, such as commercial vessels, because stack cooling can be achieved within smaller volumes. A commercial ship requiring cooling and electricity is taken as the case study for the application of the proposed system. All system components are described and analyzed in detail, in terms of modeling assumptions and configuration topology. The results show the conceptual feasibility of the proposed system configuration, since high net electrical efficiencies are accomplished. The calculated net electrical efficiency is 43.8% for a net electrical power output of 100 kWe. The heat exhausted to the absorption chiller subsystem is 107 kW and can satisfy a cooling duty of up to 128 or 64.5 kW for a LiBr–water double-effect system or a water–NH3 single-effect system, respectively. Finally, the projected total cost is comparable to conventional systems, i.e., diesel engines integrated with vapor-compression chillers, and therefore justifies further development of the proposed system.