Passive Standby Research Articles

Reliability Analysis of Industrial Model Using Redundancy Technique and Geometric Distribution

The present paper is an initiative towards analyzing the maintenance process of an industrial model using regenerative techniques. With an increase in demands to analyze the reliability of any industrial models following continuous or discrete distribution, the major concern to be considered inspect the possibility and level of failure and proceeding the failed unit for further repairing process. The system consists of two parallel units following the passive standby redundancy and with different failure mechanism. The proposed analytical methodology in the paper made it possible to assess the reliability of the whole system in the event of failure of its components. The stochastic analysis of reliability characteristics of the considered system to the types of repair time distributions was also studied using geometric distribution. The numerical equations and results being calculated for reliability parameters like mean time to system failure, availability of system in operative form, down period of the system following repair mechanism, using regenerative techniques, and geometric distribution. Graphical and analytical analysis were presented.

Stochastic analysis to mechanical system to its reliability with varrying repairing services

Reliability is enhancing its value in the advancement of echanical and industrial world by incorporating the repair mechanism, availability and manufacturing possibility of machines with varying working capacity in all conditions. The present paper is an initiative taken with a mechanical system operating with single repair server facility for varying nature of failures and services. Passive standby machine strategy is adopted for maintaining reliability at a gratified level in the system. The inspection process is included for filtering the machines according to its failure or to the level of repair services. The computed numerical and raphical data is proved to be beneficial for clarifying the profit and reliability behaviour with increasing/decreasing rate of repair mechanism and failure rate. The preference policy has been initiated for regular failure or to the failure requiring normal servicing charges and time period than major ones to avoid the waiting time for normal customer

High availability of data using Automatic Selection Algorithm (ASA) in distributed stream processing systems

High Availability of data is one of the most critical requirements of a distributed stream processing systems (DSPS). We can achieve high availability using available recovering techniques, which include (active backup, passive backup and upstream backup). Each recovery technique has its own advantages and disadvantages. They are used for different type of failures based on the type and the nature of the failures. This paper presents an Automatic Selection Algorithm (ASA) which will help in selecting the best recovery techniques based on the type of failures. We intend to use together all different recovery approaches available (i.e., active standby, passive standby, and upstream standby) at nodes in a distributed stream-processing system (DSPS) based upon the system requirements and a failure type). By doing this, we will achieve all benefits of fastest recovery, precise recovery and a lower runtime overhead in a single solution. We evaluate our automatic selection algorithm (ASA) approach as an algorithm selector during the runtime of stream processing. Moreover, we also evaluated its efficiency in comparison with the time factor. The experimental results show that our approach is 95% efficient and fast than other conventional manual failure recovery approaches and is hence totally automatic in nature.

Low power mode energy demand of household appliances—SELINA and APP projects

In the last decades, it has been recognized that energy consumption in low power modes for electrical and electronic products is an important issue. There is a need to expand energy efficiency efforts beyond simple standby modes into the new more complex area of networks, thus tackling the new paradigm of living based on the Internet of Things. The European project SELINA carried out a large scale in store monitoring campaign, measuring about 6300 different equipment. Since then, there is no reference to other similar market surveillance studies being carried out in Europe. In Asia, a market surveillance campaign performed by the Asia Pacific Partnership with measurements on a regular basis has been very successful. SELINA results show that 18.5% of the measured products present power values higher than the 2010 EC 1275/2008 regulation threshold in off-mode, and for standby this value reached 31%. When a comparison is made with the 2013 EC 1275/2008 regulation threshold, these values increase twice. The Asia Pacific Partnership results alert policy makers that low passive standby does not guarantee low active standby. Several studies indicate that consumer electronic products are becoming more efficient and their energy consumption is decreasing. However, because the ownership of appliances is also increasing, these improvements in energy efficiency do not seem to have significant impact in the overall consumption of the households. In addition, there is evidence that not all appliances in the market reach the performance announced by the manufacturers. Recent measurements carried out by the Natural Resources Defense Council on flat screen TVs revealed that their real energy consumption seems to be higher than announced in the label. This shows the urgent need for measurement campaigns, since no market surveillance is being carried out on regular basis, and trusting the manufacturer’s data seems to be unreliable.

Power saving with passive standby mode using bitmap-based activity logs for energy-efficient set-top box

A set-top box (STB) increases its energy efficiency with active standby and passive standby modes. Compared to the active standby mode, the passive standby mode saves more power by turning off more STB functions, but it results in longer activation latency. For an energyefficient STB, in this paper, power saving with the passive standby is studied. The STB operates the passive standby mode when it is not in use, and the passive standby mode is switched to the active standby mode before a user turns on the STB in order to reduce the activation latency. To do that, the passive standby uses activity logs, which are represented in a bitmap form, to find a user pattern and to predict the next user activity. In the presented power saving method with the passive standby, recent activities is reflected with more weights to quickly find a new user pattern, instead of waiting until activity logs for a new user pattern are accumulated. The method is evaluated via simulations and discussed1.

Elimination of the Transfer-Time Effects in Line-Interactive and Passive Standby UPSs by Means of a Small-Size Inverter

The main drawback of line-interactive and passive standby uninterruptible power supplies (UPS) is the transfer time when changing from normal mode of operation to battery mode of operation. During this time, the critical loads protected by the UPS are under the influence of the grid disturbance that forced the mode change. On the other hand, equipment protected by a double-conversion UPS is never affected by disturbance in the mains. Unfortunately, the efficiency of this topology is lower and its size and cost are considerably higher. Hence, the elimination of the transfer process between modes in line-interactive and passive standby UPSs would make them more competitive than double-conversion UPSs in many situations. In this paper, a method for eliminating the transfer time is proposed. It is based on a half-bridge inverter with a hysteretic controller whose output voltage is only applied to the load during the transfer time. Considering the random nature of the grid failures and the short duration of the transfer time, the design and selection of the components are nothing but standard. This also leads to a nonstandard hysteretic controller that needs to be fully analyzed. Experimental results are provided for a 750-W line-interactive UPS whose transfer time of 4 ms was eliminated by the proposed system.

An Energy-Efficient ASIC for Wireless Body Sensor Networks in Medical Applications

An energy-efficient application-specific integrated circuit (ASIC) featured with a work-on-demand protocol is designed for wireless body sensor networks (WBSNs) in medical applications. Dedicated for ultra-low-power wireless sensor nodes, the ASIC consists of a low-power microcontroller unit (MCU), a power-management unit (PMU), reconfigurable sensor interfaces, communication ports controlling a wireless transceiver, and an integrated passive radio-frequency (RF) receiver with energy harvesting ability. The MCU, together with the PMU, provides quite flexible communication and power-control modes for energy-efficient operations. The always-on passive RF receiver with an RF energy harvesting block offers the sensor nodes the capability of work-on-demand with zero standby power. Fabricated in standard 0.18-¿m complementary metal-oxide semiconductor technology, the ASIC occupies a die area of 2 mm × 2.5 mm. A wireless body sensor network sensor-node prototype using this ASIC only consumes < 10-nA current under the passive standby mode, and < 10 ¿A under the active standby mode, when supplied by a 3-V battery.

Simplified Voltage-Sag Filler for Line-Interactive Uninterruptible Power Supplies

There are three types of static uninterruptible power supplies (UPSs): passive standby, line interactive, and double conversion. The last one protects the load against all types of line disturbances, but it is the most expensive and the one with the lowest efficiency. On the other hand, passive-standby and line-interactive UPSs have higher efficiency and lower cost, but they show an important drawback: a switching time from normal to stored-energy mode. As a consequence, there is a notch in the UPS output voltage during this switching time. In a previous paper, the authors proposed a method for filling these voltage notches with a sinusoidal waveform generated by a switch-mode converter. In this one, a simplified notch filler is proposed. It consists of two capacitors, one charged with positive voltage and the other with negative voltage. If the fault occurs in the positive period, the positive-charged capacitor is connected to the load. This connection is then modulated in order to obtain a sinusoidal waveform at the load. In the negative period, the other capacitor is used in the same way.

Design of a Microcontroller-Based Passive Standby Uninterruptible Power Supply

This paper describes the design of a microcontroller-based passive standby Uninterruptible Power Supply (UPS), where the student applies a top-down systems approach to produce a working system. Such a project involves hardware-software co-design for realizing the relatively large number of detection, protection and control functions within the UPS.

Three of a kind

With uninterruptible power supplies now used in critical applications across every industrial sector, a standard terminology to describe types and performance measures has become essential. The author outlines how the international standards community has responded to this need by introducing IEC 62040-3 which distinguishes three types of UPS topology: passive standby, line interactive, and double conversion. These three topologies are described. For low power ratings (less than 2 kVA) all three topologies, as defined by the standards, are used. For medium to high power ratings, the case for the passive standby and the line interactive is, at best, marginal, in spite of their significantly lower cost. The vast majority of sales to medium to high-power rating applications are represented by double conversion UPSs (95% from a few kVA upwards; 98% above 10 kVA). The dominance of the double-conversion topology is attributable to its almost total lack of weaknesses, combined with the capacity to meet the needs of sensitive loads at these power ratings-a consequence of UPS being connected in series with the utility power sources.