Magnetic Core - Inductors and Transformers

Motivation

For realizing any practical embedded system use of Magnetics (Inductors and Transformers) are unavoidable as it is a integral part of SMPS required for control supply. In other words I can also say selecting or making Magnetics is more critical and time consuming part of complete SMPS realization. To design transformers and Inductor, we will have a short overview of magnetic cores. 

What is a Magnetic Cores?

Magnetic cores are basically a piece of magnetic material made in a particular shape. This magnetic material provide low reluctance path to magnetic flux. (Here is word reluctance for magnetic flux is similar to resistance for electric current. That is lesser the reluctance more is the flux. Air itself have very high reluctance.) 

These low reluctance magnetic cores provide low reluctance path hence guide the flux in particular path. Confining magnetic flux in particular path solve one two or both purposes. 

1. Coupling electrical coils wounded around the path i.e. on the core. By using this magnetically coupled link, the coils can exchange the electrical energy. This is a typical application of Transformers. Please refer the image blow: 

2. Storing controlled amount of energy in the magnetic flux. This is a typical application of Inductors. Inductor cores generally have gaps, either a intentionally given small air gap e.g. gaped ferrite cores (please see image below), or distributed gap like in iron dust powder cores. 

TYPES

Laminated Core

These are made up by staking thin lamination of Iron material. These cores can carry high magnetic flux density without getting saturated, but operating frequencies are quite low (as high core losses occurs at high frequency). Generally used on power frequencies (50 Hz in India)  Almost all power transformers are makeup of Laminated cores. 

Ferrite Cores 

These are made of Ferrite material in many difference shapes (EE, EI, RM, Toroids, etc). Below image shows ferrite cores of EE shape. 

These are having low saturation flux density typically 0.2 web/m^2. Because of having very low core losses, it can be operated at very high switching speeds i.e. hundreds of kHz. These are used as Inductor with a small gap in the magnetic path, or as a part of high frequency transformer with no gap. Some application like Flyback converter needs a transformer with primary winding working as a Inductor also. In such case also a gaped ferrite core is used. 

Powder Cores

Power cores are made of Iron powder dust and are mostly available in Toroidal shape. It have mixture of magnetic material and non magnetic materials. Therefore, there would be evenly distributed gap between magnetic grain. These core are used in the Inductor application generally required in DC to DC converters and SMPS application. 

GPS / GSM Based Vehicle Tracking System

INTRODUCTION

The number of vehicles is increasing at a sharp rate, and the vehicle's dispatch and safety management has become an important problem of the department of the traffic. Therefore, the demand for a system with function of positioning and monitoring rises as well. The intelligent vehicle monitoring system, based on the GPS/GSM, integtes the technology of GPS, GIS and modern commutation technologies into the monitor and management of the vehicles. With the exchange of the system information, we can not only obtain the information of trip vehicles and road blocs that are needed for decision-making in traffic engineering, bnt also can meet the demand for vehicle guards against theft, alarm and help-seeking which greatly improves the transportation efficiency and ensures traffic safety. 

ANALYSIS OF INTELLIGENT VEHICLE MONITORING AND POSITIONING SYSTEM

A intelligent vehicle monitoring and positioning system is made number of vehicle terminal, wireless communication link and vehicle monitor management center  The wireless communication link of the system can adopt tanking system, GSM network or other wireless transmission systems to achieve data transmission. The monitor management center is made up of dispatch terminal, alarm terminal, data acquisition terminal (pre-positive machine) or network communication server, dispatch statistic printing terminal and electronic map showing terminal, which make up a LAN structure. In order to realize such functions as the management and dispatch of the vehicle, all the terminals can be incorporated together in terms of the need of the work. 

Technology of Vehicle Unit's Positioning

The vehicle unit of the intelligent vehicle monitor and positioning system is made nip of the position-getting unit, wireless communication module and controlling unit. In the vehicle unit, the function of the position-getting unit is to get the position of the vehicle automatically. It is an important index for vehicle unit's function and performance that whether the vehicle unit can get the current position of the vehicle accurately and quickly  The position-getting module of the vehicle unit involves the automatic positioning technology. There are many kinds of technologies that can be used in the vehicle terminal, such as the GPS technology, the GLONASS technology, GSM cell phone positioning technology and the BEIDOUXING positioning technology. The precision and the application fields of all the positioning technologies are shown in the table below.

From table 1, the GPS technology can be found out that it is the most extensive used in the vehicle monitoring and navigation. The basic principle of the GPS pseudo-range positioning is: The satellites send their own ephemeris indexes and time information. The GPS receiver can get several pseudo-range equations in its observation range by receiving several satellites (usually four). By applying the satellite ephemeris data to these equations, three dimensional position and direction speeds of movement and time information can be obtained by the receiver. The GPS pseudo-range positioning principle sketch is as shown in figure below. 

Wireless Transmission Method of Intelligent Vehicle Monitoring System

With the development of electronics, computer science and information technology, the development of the communication system has experienced vast changes, from wire communication to wireless communication  from voice transmission to data transmission, from local area to wider areas, etc. There are many communication networks and methods that can be used in the intelligent vehicle monitor and positioning system. the applied communication manners can be sum up as follows: routine communication manner, trunking communication, GSM, GPRS and satellite communication. Different application chooses different modes of wireless communication according to the actual demand.

Based on the GSM network that owns the digital mobile cellular communication technology, the reliability can be assured in the vehicle monitor and positioning system. Short message is a kind of convenient data communication manner of GSM. Short messages of GSM will be used as the communication method of the vehicle monitor and positioning system.

DESIGN SCHEME OF GPS/GSM VEHICLE MONITORING SYSTEM

Firstly, transmitting the mobile object's information such as the dynamic position (including longitude and latitude), time, state and so on through wireless communication link to the monitoring center real-timely; Secondly, showing the position and the moving track of the mobile object on the electronic map with the strong geographical information inquiry function; Thirdly, monitoring and inquiring the information of the speed, moving direction and vehicle state of the object that users are interested in, which provides the visual foundation for dispatch. This improves the operation efficiency of the vehicle and ensures the safety of vehicle. It is especially suitable for such departments as bus service, taxi, public security, bank, insurance, airport, etc. to monitor and dispatch vehicles.

Principle of GPS/GSM Vehicle Monitoring System

Making full use of GIS, GPS and GSM technology, the vehicle monitoring system based on GPS/GSM is a computer network system developed for real-time vehicle surveillance. The positioning terminal on the monitoring object receives the positioning data from the GPS satellites (24 satellites distributed on 6 diffident earth tracks) every second by GPS module and calculates its own geographical coordinates with the data from three or more satellites. According to the established protocols, the coordinate data which include the position and the state of the vehicle are sent to GSM network in form of short message by GSM module. The GSM network transfers the received information to the communication gateway of the monitoring center. After proper handling, the information is transmitted to the GIS monitoring terminal. In this way the monitoring center can grasp detailed real-time vehicle information. When a vehicle encounters emergency, the police can be called by positioning terminal, sending the information such as the location of the vehicle, alarm type to the monitoring center. Once the information is processed, the location of the alarm vehicle can be accurately showed on the electronic map.

The principle sketch of the vehicle monitoring system based on GPS/GSM is shown in the figure below.

Design of work Structure of GPS / GSM Intelligent vehicle Monitoring System

The GPS/GSM vehicle monitoring system is made up of three major parts: monitoring and commanding center, GSM communication (including communication control machine, GSM transmission module, GSM network and corresponding wire transmission) and vehicle unit. The overall structure of the vehicle monitoring system of GPS/GSM is shown in Figure blow. 

The monitoring and commanding center consists of the communication monitoring computers, GIS monitoring terminals and other computers, which are combined by network links. The communication between communication severs and GSM network adopts the DDN special line or the wireless MODEM depending on their availability. If the monitoring objects are large in number and the communication condition permits, the DDN special line can be adopted. In this way, the communication is rapid and messages are seldom congested.

DESIGN OF MONITORING AND COMMANDING CENTER

The monitoring ad commanding center is composed of communication monitoring computers, GIS monitoring terminals, GPS database sever and database backup sever through network link. The location and state information of the mobile center are sent to vehicle monitoring and managing center by means of short message through GSM network. After analyzing the location information of vehicle, the vehicle monitoring and managing center will show the moving object dynamically on the electronic map. If the vehicle meets unexpected (stolen, robbing) situations, after receiving the alarm from vehicle, the vehicle monitoring and managing center will inform the users to take relevant measures through the form of sound or light to minimize their loss. The network structure of the vehicle monitoring and commanding center is as shown in figure below. 

DESIGN OF VEHICLE UNIT

The vehicle unit is installed on the vehicle and other mobile devices. It is constituted by GPS receiver,  antenna, processing unit, GSM module and hand-free devices. GPS receiver demodulates positioning data of GPS satellites through the aerial, the process unit receives data from serial port, and the data is sent to message center after modulated. The alarm function is used in the condition that the vehicle or mobile device breaks down or pre-warns, and then the driver can press down the hidden alarm button to call the police, or is catenated with the vehicle alarm, and sends out warning information automatically. The alarm information includes the number, the state, and the location of the vehicle. The dispatch center will take relevant reactions after receiving the alarm. The structure sketch of the GPS/GSM vehicle unit is as shown in figure below. 

DESIGN OF COMMUNICATION GATEWAY

The communication gateway of the vehicle monitoring system is responsible for bidirectional information transmission between monitoring platform and the vehicle unit. The communication gateway comprises two parts: one is installed in the communication sever (COM SEVER): the other is installed on the communication client (COM CLIENT). The software of the communication gateway can be realized by using Visual C++. There are two processes in the communication sever: one is PROCESS GSM which is required to changing short messages into a uniform format, storing it in the short message queue temporarily waiting for inquiry of

COMM CLIENT; the other process is PROCESS CLIENT, which is used to monitor the inqiwry command of COMM-CLIENT, returning the short messages in the same format, at the same time receiving the monitoring command from the COMM-CLIENT and sending the message to vehicle unit with the DDN special line or wireless MODEM communication protocol by GSM network. The COMM CLIENT is suggested to design into a dynamic link library, with the following functions: judging whether there is short message needed, receiving short message, sending short message command.

FUNCTIONAL REALIZATION OF GPS / GSM VEHICLE MONITORING SYSTEM

1) Vehicle real-time monitoring

The information of the vehicle track and state can be shown on the electronic map in the dispatching center,

insuring the dispatching center to monitor the vehicle real timely.

2) Track playback

The location record of a vehicle, the received information of a vehicle and the alarm information in a period, etc. can be inquired at any time. And can select the position record in some time of a vehicle and carry on the track playback.

3) Road matching

According to longitude, latitude, moving direction, moving speed of the object and the road information on the electronic map, shows the vehicle object in the center of the road.

4) Routine choices

The system may provides routine choices for different conditions.

5) Voice link

The system allows two-way voice-communication when transmitting the position information of the vehicle.

6) Information inquiries

Users can real-timely inquire the information of the location of authorized vehicle and state, etc.

7)Acceptation of active alarm

When a vehicle is robbed or thieved, the vehicle terminal will send the alarm information to the center. The watcher will be noticed at the monitoring terminal through voice or ray, and the data such as the location of the vehicle (X, Y coordinate), the time of moving object will be shown on the screen. The decision of the accident will be offered for the vehicle manager. For the safety of the vehicle, on receiving the alarm information from the vehicle, the monitoring center will send the alarm information to the owner of the vehicle, noticing that the vehicle meets accident, and the owner will be supposed to take relevant actions.

8) Acceptation of stolen alarm

When the door of vehicle is prized illegally, the vehicle terminal will send the stolen alarm to the center. The

watcher will be noticed at the monitor terminal through voice or ray, and the data such as the location of the v-chicle (X, Y coordinate); time of moving object will be shown in the screen. The decision foundation of the accident will be offered to the vehicle manager. For the safety of the vehicle, on receiving the alarm information from the vehicle, the monitoring center will send the alarm information to the owner of the vehicle, noticing that the vehicle meets accident, and the owner will take relevant actions.

9) The special incident alarm

Whee met the special incident, the monitoring center will be alarmed, and the location of the vehicle will be signed with special signal. After sending the alarm information to center. the watcher will be noticed at the monitoring terminal through voice or ray, and on the electronic map the object will be signed with fresh color and special icon. The owner data will be shown in the character monitoring platform, including the number of the vehicle, license number of the vehicle, the vehicle type, the vehicle color, the motor number, using type, driver's name the license number of the driver, the department of the vehicle, the director, the telephone number, the location (X, Y coordinate), the speed, the type of the alarm and time, to help the watcher deal with alarm. The system can provide the alarm condition acceptation window for the watcher to record the acceptation condition.

10) The communication function of TCP/IP

The GIS monitoring and managing center may make communication connection through TCP/IP protocol and communication gateway to realize the monitoring and dispatching of the vehicle positioning terminal .

REFERENCES: 

Qiang Liu; Huapu Lu; Hongliang Zhang; Bo Zou; , "Research and Design of Intelligent Vehicle Monitoring System Based on GPS/GSM," ITS Telecommunications Proceedings, 2006 6th International Conference on , vol., no., pp.1267-1270, June 2006

What is RFID?

Radio frequency identification (RFID) has been around for decades. Only recently, however, has the convergence of lower cost and increased capabilities made businesses take a hard look at what RFID can do for them.A major push came when retailing giant Wal-Mart dramatically announced that it would require its top 100 suppliers to supply RFID-enabled shipments by January 2005. Though the bottom line story of that deployment has yet to surface.

Following obvious questions will strike on anybody's mind:

• What is RFID, and how does it work? 

• What are some applications of RFID? 

• What are some challenges and problems in RFID technology and implementation?

• How have some organizations implemented RFID?

TECHNICAL OVERVIEW

The basic premise behind RFID systems is that you mark items with tags. These tags contain transponders that emit messages readable by specialized RFID readers. Most RFID tags store some sort of identification number; for example a customer number or product SKU (stock-keeping unit) code. A reader retrieves information about the ID number from a database, and acts upon it accordingly. RFID tags can also contain writable memory,which can store information for transfer to various RFID readers in different locations. This information can track the movement of the tagged item,making that information available to each reader.

RFID tags fall into two general categories, active and passive, depending on their source of electrical power.Active RFID tags contain their own power source, usually an on-board battery. Passive tags obtain power from the signal of an external reader. RFID readers also come in active and passive varieties, depending on the type of tag they read. 

Active tags transmit a stronger signal, and readers can access them from further away.The on-board RFID offers tantalizing benefits for supply chain management, inventory control, and many other applications. Power source makes them larger and more expensive, so active RFID systems typically work best on large items tracked over long distances. Low-power active tags are usually slightly larger than a deck of playing cards.Active tags can remain dormant until they come in range of a receiver or can constantly broadcast a signal. Because of their on-board power source,active tags operate at higher frequencies—commonly 455 MHz,2.45 GHz, or 5.8 GHz—depending on the application’s read range and memory requirements.Readers can communicate with active RFID tags across 20 to 100 meters.

Passive tags, on the other hand, are very inexpensive; they can cost as little as 20 cents apiece, and new technologies are constantly making them cheaper to integrate into common materials and products.Because passive tags are inexpensive, they will likely be the basis of most of the growth in RFID implementations. In addition to their low cost, passive tags can also be quite small. Current antenna technology limits the smallest useful passive tag to about the size of a quarter. The larger the tag, the larger the read range. Currently, passive RFID tags contain about 2 Kbits of memory. This is too small to hold much more complex information than identification and history information. The technology behind RFID is constantly improving, so the amount of information and capabilities of RFID tags will increase over time, allowing RFID tags to eventually contain and transmit much more information. A passive-tag reader can constantly broadcast its signal or broadcast it on demand. 

When a tag comes within the reader’s range, it receives an electromagnetic signal from the reader through the tag’s antenna. The tag then stores the energy from the signal  in an on-board capacitor, a process called inductive coupling.When the capacitor has built up enough charge, it can power the RFID tag’s circuitry, which transmits a modulated signal to the reader. That return signal contains the information stored in the tag. The communication between the reader and passive tag uses one of two methods to modulate the ID signal. 

In low-frequency (less than 100 MHz) tags pass information by releasing energy from the capacitor to the tag coils in varying strengths over time, which affects the radio frequency emitted by the tag. The reader detects these varying waves and can use these variances to demodulate the code. Figure below shows this load modulation.

In higher-frequency (greater than 100 MHz) tags,the tag transmits the signal using back scatter, in which the tag’s circuit changes the resistance of the tag’s antenna. This change in resistance causes a transmission of RF waves, which the reader can pick up and demodulate. Passive tags typically operate at frequencies of 128 KHz,13.6 MHz,915 MHz, or 2.45 GHz, and have read ranges of a few inches to 30 feet. Frequency choice depends on the system’s environment,what material the signal must travel through, and the system’s required read range.

RFID tags can be encased in many materials.Plastics are a very common material for RFID, forming  identification cards for building access,credit cards,or bus fares.Tags can also go on the back of labels printed on standard ink jet printers, for placement on inventory.

STANDARDS:

Several RFID standards exist, and their applications are under debate within the RFID development community. These standards cover: 

• identification, the coding of unique item identifiers, or other data on the RF tag;

• data and system protocols, effectively the middleware of an RFID system;

• the air interface, that is, the wireless communication between the reader and the tag;

• application support, which provides advice about how to implement the technology;

• testing, compliance, and health and safety, that is, the rules that govern RFID operations; and

• terminology.

The International Standards Organization (ISO) has three standards for RFID: ISO 14443 (for contactless systems), ISO 15693 (for vicinity systems, such as ID badges), and ISO 18000 (to specify the air interface for a variety of RFID applications). A not-for-profit organization, EPCglobal, has developed a widely accepted standard for product identification. The Electronic Product Code (EPC) standard covers the air interfaces, the format for the product identification data stored in an RFID tag, and the middleware and databases storing information about the tags.

APPLICATION:

RFID applications are numerous and far reaching. The most interesting and widely used applications include those for supply chain management,security,and the tracking of important objects and personnel. Supply chain management In supply chain management, RFID tags are used to track products throughout the supply chain—from supplier delivery, to warehouse stock and point of sale. New applications target tracking from checkout through customer billing. A central database records product movement, which manufacturers or retailers can later query for location, delivery confirmation, or theft prevention. For this application, RFID basically serves as a replacement for the bar code scanners used to track products and shipments in similar ways.

Security and personal identification applications are a major and broad application of RFID. A common use of RFID is in identification cards to control building access. Many organizations use RFID tags embedded in ID cards, which are readable at a building entrance. On a similar note,some credit cards use RFID tags. Other cards use tags for automatic fare payment in mass-transit systems, such as the SmarTrip card for the Washington DC area subway and bus system (http://www.wmata.com/riding/smartrip.cfm). Essentially,these are a replacement for identification cards with magnetic stripes, providing a more reliable way to store identification information—magnetic stripes tend to wear out and lose information over time. RFID tags also have a higher memory capacity than magnetic stripes.

RFID Keys: RFID tags that work with a reader near the car’s ignition switch.The reader will only accept codes stored in certain keys. If the code in a key does not match the reader in the car,the car will not start, making it more difficult to steal vehicles by copying keys. 

Movement tracking: Because moving objects can easily carry RFID tags, a common use is to track the movement of people and the information associated with them.Some hospitals now use tags on newborns, to ensure identification and to alert hospital staff should someone attempt to take the baby outside of the hospital without authorization. Some schools are requiring children to wear tag-embedded bracelets or wrist bands while on school grounds, to monitor attendance and to locate lost children. The FDA recently approved a RFID tag that could stay with surgical patients in hospitals and store information on the surgical procedure the person requires, eliminating surprisingly common surgical mistakes (“FDA Approves Surgical ID Tag,”S.Lawrence,eWeek,Nov.2004; http://www.eweek.com/article2/0,1759,1731402,00.asp). Hospitals are also using RFID to track equipment throughout a facility as it moves from room to room.This

helps manage inventory and ensure the proper maintenance of equipment. Libraries also tag books, making it

possible to easily locate a book in the stacks, prevent theft, and automate the checkout process.

CHALLENGES AND ISSUES IN RFID

Although promising, RFID is not without its challenges, which arise from both a technological and usage point of view. Privacy concerns A common concern with RFID is privacy. It is disconcerting for many people to have their movements or buying habits automatically tracked electronically. Many privacy groups are concerned about the ability to identify people as they walk through a store or shopping center via the tags embedded in their clothing and linked to them at the time of purchase. To counter such concerns, RFID proponents propose that retail tags have “kill switches” that disable the tag at the point of sale. Even though a small tag might remain embedded inside a product, once the kill switch is activated, the tag would no longer transmit information. 

Many of the privacy concerns regarding RFID are addressable because of the nature of RFID tags themselves. The read range of RFID tags is much too small to allow readers out of personal range to read tags carried on a person or in a vehicle. Also, building materials tend to absorb the relatively weak RF waves transmitted by passive tags,making it extremely difficult to pick up RFID signals through the walls of a home. However, anytime someone automatically stores and tracks personal identification in electronic databases, privacy concerns are very real. RFID tags used in transportation systems—whether for fare collection on mass transit systems or automatic toll payment on bridges and highways—allows for the easy and unprecedented tracking of movement. If you can pay for products in an RFID tag and companies later bill you automatically, it takes all possible anonymity out of the retail process. Companies and government agencies must address these concerns before the public will truly feel comfortable using RFID systems. People will want to see policies about the use of  an RFID system and the information it collects. Security Security is another key issue in RFID. An organization that implements RFID in its supply chain does not want competitors to track its shipments and inventory. People who use devices that carry personal financial information, such as credit card or other ID numbers, do not want others to access their accounts. These are significant security vulnerabilities in RFID.

Some researchers have proposed schemes that would require tags to authenticate readers, transmitting information only to authorized readers.The tags would have to store ID numbers for authorized readers, and a reader would have to broadcast its ID to the tag. To protect the reader’s ID—and prevent others from eavesdropping and stealing the information—the reader uses either a fixed or randomly generated number to hash (encrypt) its ID (Gao and colleagues). If the tag cannot authenticate the reader’s identity, the tag will refuse to transmit the information it stores. Like most security tactics, this scheme is vulnerable to attacks,

such as man in the middle, or reverse engineering. 

Integration with legacy systems is another challenge to RFID. Several vendors are developing RFID middleware that will link new RFID systems into existing back-end infrastructures. Middleware, for example, can help with the current lack of standards in RFID. If an organization picks a standard that changes or loses its market prevalence, middleware can transform the data  from readers into the format supported by back-end systems. Many RFID middleware systems provide hooks into operational monitors,so organizations can monitor their tagged items in real time. Middleware can provide the primary link between RFID readers and databases.

RFID, a technology existing for years, has potential uses in a variety of applications.Though not without issues and challenges, RFID is a promising technology which analysts expect to become ubiquitous in the coming years,helping organizations solve problems in supply chain management, security, personal identification, and asset tracking.

References:

Weinstein, R.; , "RFID: a technical overview and its application to the enterprise," IT Professional , vol.7, no.3, pp. 27- 33, May-June 2005

Smart Meters for Smart Grid

Smart meter is an advanced energy meter that measures consumption of electrical energy providing additional information compared to a conventional energy meter. Integration of smart meters into electricity

grid involves implementation of a variety of techniques and software, depending on the features that the situation demands. Design of a smart meter depends on the requirements of the utility company as well as the customer. In fact, deployment of smart meters needs proper selection and implementation of a communication network satisfying the security standards of smart grid communication.

Image blow shows metering architecture of conventional and smart meter system. 

Communication technologies to be chosen have to be cost efficient, should provide good transmittable range, better security features, bandwidth, power quality and with least possible number of repetitions. Bluetooth technology can be a possible option for communication of control signals and to transmit energy consumption

data. In the view of implementing this technique, Koay et al. proposed a Bluetooth based energy meter that can collect and transmit the energy consumption data wirelessly to a central base station. Power Line Carrier (PLC) and Broadband Power Line (BPL) communications are the other possible options of data transfer supporting the higher level communication suites such as TCP/IP. One of the popular communication technologies is PLC, which uses the existing electricity grid, cellular/pager network, mesh network, combination of licensed and unlicensed radio, wireless modem, existing internet connection, power line communication, RS-232/485, Wi-Fi, WiMAX, and Ethernet with protocol to upload data using IEC DNP. PLC technology is highly efficient for automation of data in smart meter applications. In spite of substantial overhead caused by the large IPv6 header, this protocol can be applied even at low PHY layer data rates. This technology, with the combination of the MAC algorithm can achieve satisfactory delay times and throughput. Though this combination might slightly reduce the usable data transfer rate, it will not affect the overhead at MAC layer. IP based network protocol would be another promising option for communication because of its advantages over other technologies while satisfying the security standards of the smart grid communications. In addition, TCP/IP technology can also be used as a common platform for multiple

communication devices.

Figure below shows communication network for smart meter:

References:

1. Smart meters for power grid: Challenges, issues, advantages and status (Review Article) Renewable and Sustainable Energy Reviews, Volume 15, Issue 6, August 2011, Pages 2736-2742 Soma Shekara Sreenadh Reddy Depuru, Lingfeng Wang, Vijay Devabhaktuni

2. Koay BS, Cheah SS, Sng YH, Chong PHJ, Shum P, Tong YC, et al. Design and implementation of bluetooth energy meter. In: Proc. Fourth International Conference on Information, Communications & Signal Processing. 2003. p. 1474–7.

Smart Grid and Communication Technologies

The idea of Smart Grid has started to evolve more rapidly with the enhancement in Communication Technologies. One important feature of the smart grid is the integration of high-speed, reliable and secure data communication networks to manage the complex power systems effectively and intelligently. As these communication networks are responsible for delivering power system related messages, we discuss specifically the network implementation considerations and challenges in the power system settings.

Above figure is an illustrative framework of next-generation power grid, where A is a wind power plant, B is a large hydro power plant, C is a coal-fire power plant, D is a geothermal power plant, E and F are houses with solar-electricity generation, G and H are houses with wind-electricity generation, I is the power transmission infrastructure, J is the communication infrastructure, and K–Q are the seven constituent domains that are bulk generation, transmission, distribution, operation, market, customer, and service provider, respectively.

Above figure is an example of communication architecture in smart grid, where A is a power substation, B is   segment of power transmission lines, C is a PEV charging station, D is a residential subdivision installed with solar panels, E is a residential complex with AMI, and F is an energy smart house with electric appliances connected to the smart grid. The Internet and ISPs serve as the backbone in connecting the distributed subnetworks.

Some major communication technologies include IEEE specified ZigBee, WiMAX and Wireless LAN (Wi-Fi) technologies, GSM 3G/4G Cellular, DASH 7 and PLC (PowerLine Communications), with special focus on their applications in Smart Grids. The Smart Grid environments and domains such as Home Area Automation, Substation Automation, Automated Metering Infrastructure, Vehicle-to-Grid Communications, etc. are considered as priority areas for developing smarter grids.

Blow image shows penetration level of different communication technologies for smart grid.

References: 

1. A survey on the communication architectures in smart grid

Computer Networks, Volume 55, Issue 15, 27 October 2011, Pages 3604-3629

Wenye Wang, Yi Xu, Mohit Khanna

2. Evolution of Communication Technologies for Smart Grid applications Review Article

Renewable and Sustainable Energy Reviews, Volume 19, March 2013, Pages 191-199

Ahmad Usman, Sajjad Haider Shami

Embedded Processor complexities for Smart Grid

Before we explore on processing element for Smart grid. Lets understand the meaning of smart grid itself. It's meaning is vary vast and vague and there is no common definition for it. In current time it is of high interest for researchers, developers and governments and it is basically a newer version of conventional power system.

I myself understand Smart grid as power system which have bi-way communication between electricity department and consumer, integrating lots of intelligence in power control and billing charges control, integrating lots of renewable energy sources in it, applying lots of advance power electronics techniques to make more reliable, safe and high quality power. there is lots to add on .......

To achieve all above mentioned functionality of Smart Grid, the role of embedded processors will be to achieve high performance in the given real time situations. The embedded processors carry out tasks similar to security encryption, signal processing, power flow calculation etc. which are essential for data analysis and proper data transmission. Depending on where the embedded processor is in the smart grid hierarchy, the application running on the processor will be different. There must be a need for a new design in the micro-architecture of the processors specifically for Smart Grid application to achieve these complex tasks.

Distributed computing in the grid will help tackle the bottlenecks produced by various devices communicating with each other. Inexpensive computing solutions and memory nodes in the field are expected to redefine electric grid management because of the availability of ubiquitous wireless computing on every critical node of the smart grid. The computations could be for power flow calculations, security encryptions etc. all running

simultaneously. This motivates the need for a new improved and customized design for an embedded processor in the smart grid

Design space exploration for an embedded processor involves finding the values for the design parameters resulting in optimal performance. Optimizing one parameter at a time is a method which cannot be used as there are too many interactions among the parameters. When the design is for a multi core processor the design space increases multiple times.  The applications in the smart grid are diverse and require embedded processors which are fundamentally different in the micro-architecture.

Reference:

Sai, Rohith Tenneti Seetha, et al. "Architecture Exploration of a Heterogeneous Embedded Processor for the Smart Grid." Southeastcon, 2012 Proceedings of IEEE. IEEE, 2012.

E-Health Care by using 2nd generation RFID system

Radio frequency identification technology has received an increasing amount of attention in the past few years as an important emerging technology. However, the intrinsically passive features of existing RFID systems, to which we refer as first-generation RFID systems, render their adaptation to real-world dynamics in order to efficiently  comply with up-to-date application specific requirements difficult. To address this challenging issue, evolution of  second-generation RFID systems is in progress. 

2nd generation RFID is characterized by the introduction of encoded rules that are dynamically stored in RFID tags. If we say it in simple words it is capable of sending dynamically changing data to RFID reader not like the 1st generation RFID system which just send a static ID. 

This novel approach facilitates the systems’ operation to perform actions on demand for different objects in different situations, and enables improved scalability. Based on 2G-RFID-Sys, many problems can be solved, a novel e-healthcare management system is an example of that. It is foreseeable that the flexibility and scalability of 2G-RFID System will support more automatic and intelligent applications in the future.

Figure blow shows diagram representation of the 2G-RFID-Sys based e-healthcare system. 

Sensors for checking the health parameters, like heartbeat etc are attached with Patient's body and RFID tags given information/data to RFID reader about it. As per network shown in the diagram any medical emergency and Patients data are directly communicated to hospital, ambulance and concerned doctors. 

Reference: 

Chen, Min, et al. "A 2G-RFID-based e-healthcare system." Wireless Communications, IEEE 17.1 (2010): 37-43.