Power-Electronics-Based Solutions for Plug-in Hybrid Electric Vehicle Energy Storage and Management Systems

Batteries, ultracapacitors (UCs), and fuel cells are widely being proposed for electric vehicles (EVs) and plug-in hybrid EVs (PHEVs) as an electric power source or an energy storage unit. In general, the design of an intelligent control strategy for coordinated power distribution is a critical issue for UC-supported PHEV power systems. Implementation of several control methods has been presented in the past, with the goal of improving battery life and overall vehicle efficiency. It is clear that the control objectives vary with respect to vehicle velocity, power demand, and state of charge of both the batteries and UCs. Hence, an optimal control strategy design is the most critical aspect of an all-electric/plug-in hybrid electric vehicle operational characteristic. Although much effort has been made to improve the life of PHEV energy storage systems (ESSs), including research on energy storage device chemistries, this paper, on the contrary, highlights the fact that the fundamental problem lies within the design of power-electronics-based energy-management converters and the development of smarter control algorithms. This paper initially discusses battery and UC characteristics and then goes on to provide a detailed comparison of various proposed control strategies and proposes the use of precise power electronic converter topologies. Finally, this paper summarizes the benefits of the various techniques and suggests the most viable solutions for on-board power management, more specific to PHEVs with multiple/hybrid ESSs.      

Managing technology development for safety-critical systems

This paper presents a model that determines the optimal budget allocation strategy for the development of new technologies, for safety-critical systems, over multiple decision periods. The case of the development of a hypersonic passenger airplane is used as an illustration. The model takes into account both the probability of technology development success as a function of the allocated budget and the probability of operational performance of the final system. It assumes that the strategy is to consider (and possibly fund) several approaches to the development of each technology to maximize the probability of development success. The model, thus, decomposes the system's development process into multiple technology development modules (one for each technology needed), each involving a number of alternative projects. There is a tradeoff between development speed and operational reliability when the budget must be allocated among alternative technology projects with different probabilities of development success and operational reliability (e.g., an easily and quickly developed technology may have little robustness). The probabilities of development and operational failures are balanced by a risk analysis approach, which allows the decision maker to optimize the budget allocation among different projects in the development program, at the beginning of each budget period. The model indicates that by considering reliability in the R&D management process, the decision maker can make better decisions, optimizing the balance between development time, cost, and robustness of safety-critical systems.     

Steady-State Performance and Stability Analysis of Mixed Pole Machines With Electromechanical Torque and Rotor Electric Power to a Shaft-Mounted Electrical Load

This paper presents the steady-state model, performance, and stability analysis of a mixed pole machine with a new operational mode which provides a rotor torque and an n -phase rotor electrical output power to a shaft-mounted rotating electrical load. The machine operated under this mode can be used in applications that require contactless power, such as in robotics, or applications that require independent control of both rotor torque and rotor electric power, such as for contactless rotational antennas and turret systems. The performance assessment includes electromagnetic torque, electrical efficiency, mechanical efficiency, and total efficiency based on both simulation and experimentation. The effect of electrical loading and stator voltage on both rotor torque and rotor electric power is also considered. The machine steady-state stability is introduced by plotting the machine operating characteristics that determine all stable operating regions of the machine under the proposed mode of operation.     

The role of systems and applications monitoring in operational risk management

Operational risk management is a reflection of the need for enterprises to demonstrate that they are prepared for all eventualities, through monitoring day-to-day operational risks. IT is an area that is critical to modern enterprises and consequently carries with it the capacity to cripple those same enterprises — business disruption as a result of IT failure is a major area of operational risk. Modern IT in many enterprises, especially large ones such as BT, is distributed and heterogeneous. This presents challenges to collecting and correlating management, monitoring and audit data in a timely manner. It also highlights the need to take an end-to-end view, with data collected from a number of sources and presented as an integrated picture of the health of a business solution. In an eBusiness environment, there is also a need to manage, monitor and audit the IT interfaces with customers, suppliers and partners. This paper looks at operational risk in an IT context and provides an overview of the contribution made by systems and applications monitoring to successful operational risk management. This paper has concentrated on using monitoring to address the downside of risk and reflects a culture in many organisations to eliminate or minimise risk. However, risk has an upside whereby an enterprise can gain competitive advantage through ‘right setting’ risk tolerance — this advantage can only be gained when the organisation begins to understand and articulates its risk appetite. Monitoring can contribute significantly to the upside through supplying the information required to manage and control the risk exposure to perform within the accepted risk appetite, facilitate risk taking and imbue a better risk culture in the organisation.     

Proper Framework for the Application of Power Management Algorithms

A power aware system can reduce its energy dissipation by dynamically powering off during idle periods and powering on again upon a new service request arrival. We minimize the dissipated energy, by selecting the optimal waiting interval before powering off, under consideration of the expected time of the next arrival. This approach has been already proposed in the past, using the idle times distribution, rather than the interarrival periods captured at the moment of service completion. Algorithms proposed in the literature utilize the history of idle periods or assume a vanishing service time. There has been no clear proposition on how service time affects the time instance of our power off decision; rather, whenever service time has been significant, a “blurred” image of the system’s characteristic and a corresponding approximated optimal policy occurred. We clearly show analytically and experimentally that the idle times distribution should not be used as a primary design input, since it is the product of two separate inputs; the interarrival times and the service times. We give insight to our problem, using a mechanical equivalent established at the moment of service completion of all pending requests and show through analytical examples how service time affects our power-off decision. We explain the paradox of being advantageous to wait for intervals more than the shutdown threshold (which is a system characteristic) and show how the introduction of idle period lengths instead of interarrival periods “blurs” the input distribution, leading to non-optimal decisions. Our contribution is to define and solve the proper problem, solely relying on the interarrival distribution. Further, we examine the problem under the framework of competitive analysis. We show how the interarrival distribution that maximizes the competitive ratio, being an exponential distribution, intervenes with power management; it renders the optimization procedure worthless through its “memoryless property”. Exponential interarrivals, irrespective of the service time pattern, are the marginal case where we cannot obtain energy gains. In all other cases the framework we promote ensures considerable advantages compared to other approaches in the literature. Moreover, it leads to a self contained module, implementable in software or hardware, which is based on an iterative formula and thus reduces power management calculations significantly. Here we exploit all operational features of the problem in proposing an implementation which spreads computations over the whole of the waiting period. We extensively compare our results numerically both against claimed expectations and against previous proposals. The outcome fully supports our framework as the one most appropriate for the application of power management.Part of this work has been supported by the EU IST-2001-34157 project PACKWOMAN (Power Aware Communication for Wireless Optimised Personal Area Networks).     

The Japanese Way of Management

This paper presents a series of frameworks for analyzing and understanding the Japanese way of management which presumably has contributed to the phenomenal growth of the Japanese economy for the past quarter century. The treatment is limited to the context of practice of the so-called rationality-oriented aspects of management, especially to the application of operations research (OR), management science, and possibly also computer technology, to the solution of management decision problems. It encompasses not only the application of other, basic management technologies such as statistical quality control (SQC) and industrial engineering (IE) but also more comprehensive areas of practice such as management information systems (MIS).     

Control and dynamics of constant-power-loss-based operation ofpermanent-magnet synchronous motor drive system

The operational envelope of electrical machines is limited by the maximum permissible power loss of the machine at any given speed. The control and dynamics of the permanent-magnet synchronous motor (PMSM) drive operating with a maximum power loss versus speed profile is proposed in this paper. The proposed operational strategy is modeled and analyzed. Its comparison to the conventional strategy of limiting current and power to rated values demonstrates the superiority of the proposed scheme. The implementation of the proposed strategy is developed. It is achieved with an outer power loss feedback control loop. This has the advantage of retrofitting the present PMSM drives with the least amount of software/hardware effort. The PMSM drives in this case then can use the existing controllers to implement any torque control criteria, such as constant torque angle, unity power factor, constant air-gap flux linkages, maximum torque per unit current, or maximum-efficiency operation. Experimental verification of the new operational strategy is provided. The concepts presented in this paper can be applied to all other types of motor drives     

DYNAMO: A Cross-Layer Framework for End-to-End QoS and Energy Optimization in Mobile Handheld Devices

In this paper, we present the design and implementation of a cross-layer framework for evaluating power and performance tradeoffs for video streaming to mobile handheld systems. We utilize a distributed middleware layer to perform joint adaptations at all levels of system hierarchy - applications, middleware, OS, network and hardware for optimized performance and energy benefits. Our framework utilizes an intermediate server in close proximity of the mobile device to perform end-to-end adaptations such as admission control, intelligent network transmission and dynamic video transcoding. The knowledge of these adaptations are then used to drive "on-device" adaptations, which include CPU voltage scaling through OS based soft realtime scheduling, LCD backlight intensity adaptation and network card power management. We first present and evaluate each of these adaptations individually and subsequently report the performance of the joint adaptations. We have implemented our cross-layer framework (called DYNAMO) and evaluated it on Compaq iPaq running Linux using streaming video applications. Our experimental results show that such joint adaptations can result in energy savings as high as 54% over the case where no optimization are used while substantially enhancing the user experience on hand-held systems.     

A decision support algorithm to assess cost-effective control ofdetriments associated with a production planning system

In systems where production of a commodity or service is accompanied by simultaneous generation of detriments, reduction of the latter usually implies increase in production cost. This leaves considerable scope for sustainable decisions regarding the extent to which control of detriments can be done in a cost effective manner. One example of such a system is production of power over an energy management scenario, where control of pollution from thermal units attracts considerable interest due to the environmental and economic implications. This paper presents an approach that decides the optimality for cost effective control of detriments accompanying a production process. The total burden on the production system is viewed in terms of two components, namely, a cost burden and a detriment burden; both considered relative to their values for the base case, which incorporates no control for detriments. The cost effective decision is obtained as an optimal tradeoff between the two burdens. The concept is formulated for the general production planning system, as well as for application to an energy management scenario. An illustrative case study adapted from the existing Indian energy scenario is used to highlight the applicability of the approach     

In search of energy-efficient mobile networking

With the proliferation of mobile fixed-power devices, energy consumption emerged as a vibrant research and development subject area in networking. Mobile devices are designed with several hard constraints such as low cost and small geometries, as well as, low heat dissipation, and operation using fixed power sources. Manufacturers have been adding an ever increasing set of features to small mobile devices, which are no longer binary-use gadgets, but fully-fledged computers. With respect to power management, several mechanisms have been introduced; but, by and large, gains in power consumption at the hardware level have been essentially traded for extended functionality. All in all, the overall operational time has not increased. For example, early GSM cellular phones could only allow for less than an hour of talk time in a single battery charge. By the late 1990s, top models, introduced through better engineering and an evolutionary development approach, featured talk times increased by a factor of 3-5. This level of performance has remained the same over the last decade, although it is well below user expectations. This article reviews the evolution from simple cell phones toward the feature-rich mobile networked devices we have come to expect from manufacturers, and explains the factors that have led to stagnation in operational time. We then turn our attention to the multiaccess nature of modern mobile devices and the respective implications for power management. We find that the current host-centric mobile networking paradigm, based on end-to-end always on connectivity, leads to energy-inefficient operation. Finally, this article introduces information-centric networking and outlines open research issues in the design of energy-efficient future Internet architectures.     

Application of control plane technology to dynamic configurationmanagement

The distinction between switched and leased line services is beginning to disappear. Many network operators and suppliers are developing control plane technology for application in transport networks. This will allow faster service provisioning, particularly between network operators, and the creation of new network services. However, such systems will still require comprehensive management systems, and successful operators and vendors of the future will be those that are capable of developing operational support systems that complement the control plane with service management capabilities, automated plan and build processes, inventory management, and capacity planning. This article examines the distribution of functionality between the management and central planes for support of soft permanent and switched connections     

Network management and control systems and strategic issues

The development of a network management strategy and a network control system for the large integrated telecommunications network (ITN) at American Express Travel Related Services Company is discussed. Network control relates to operational activities such as the diagnostics, configuration, monitoring, and performance of networks, and network management relates to all of the functions performed to manage network resources. An architecture that addresses both control and management requirements is described. Network control functions are consolidated so that operations have a single interface to the system and can operate dissimilar systems from a single workstation. NETVIEW, a licensed IBM software, performs the functions of a focal point, and the network element management system (NEMS) addresses the management of network elements. The centralization of alarms and/or alerts and issuance of commands provides immediate capability to monitor and resolve network problems through a single set of terminals as well as a platform for further automation through the use of artificial intelligence technology     

A Guard Dog Perspective on the Role of Media

A guard dog perspective is offered as a way to better understand the functioning of the mass media as an important set of communication agencies in the social system. This perspective takes into account the varying role performances by mass media in reporting on major public issues. The guard dog metaphor suggests that media perform as a sentry not for the community as a whole, but for groups having sufficient power and influence to create and control their own security systems. This conception is delineated from other perspectives, which include (a) the traditional fourth estate role of watchdog media, (b) the lapdog view of submissive media, and (c) the view of media as part of a power oligarchy. Several hypotheses that may be derived for testing the utility of the guard dog perspective are suggested and discussed in light of various bodies of evidence available.     

Home automation

The impact of home automation on domestic lifestyles will be as far ranging as was that of factory automation on industry and its benefits will be available to all sectors of society. Home automation will be achieved not with the household robot but with embedded computing power and memory within dozens of pieces of domestic equipment, each of which will communicate with the user and with other equipments. Within the integrated home system the communication media will include infra-red, radio, mains wires, installed twisted wires and coaxial cable, and later perhaps optical fibre. Applications will include security, lighting, heating, cooking, washing appliances, audio and video systems, energy management as well as a number of new applications such as health monitoring, home publishing etc. A large standards activity is in place by the major manufacturers of domestic equipment throughout Europe to ensure that their equipments are reliable and compatible     

Multibeam antenna-based topology control with directional power intensity for ad hoc networks

This paper proposes a new approach that applies multibeam directional antennas to controlling topology by reducing the power intensity directionally instead of omnidirectionally. In contrast to omnidirectional topology control, which reduces transmission power (and, thus, the resulting transmission range) in all directions, the proposed approach maintains the original power range in certain directions while clearing the power intensity in other directions. This paper shows that the proposed approach and the. omnidirectional topology control approach are equivalent in terms of the probability distribution of the number of symmetric neighbors in their resulting topologies. Major benefits of this approach include reduced and steady hop count, power saving independent of the number of neighbors within the original power range, and symmetric link in terms of SNR quality, as compared to omnidirectional topology control approaches. Simulation studies have demonstrated these benefits and highlighted its trade-offs.     

Inter-operator OSS Interface for Delivering Pan-European ATM VP Service

The provision of ATM virtual paths across multiple network domains requires interaction between the operational support systems (OSS) used by the different network operators to manage those networks. This paper describes the interfaces needed between such OSS to support performance and accounting management. It also describes an approach to ensuring those interfaces are secure. The results may be suitable for operational deployment and applicable with further development for other ATM services such as virtual circuits and switched services.     

Security of industrial sensor network-based remote substations in the context of the Internet of Things

The main objective of remote substations is to provide the central system with sensitive information from critical infrastructures, such as generation, distribution or transmission power systems. Wireless sensor networks have been recently applied in this particular context due to their attractive services and inherent benefits, such as simplicity, reliability and cost savings. However, as the number of control and data acquisition systems that use the Internet infrastructure to connect to substations increases, it is necessary to consider what connectivity model the sensor infrastructure should follow: either completely isolated from the Internet or integrated with it as part of the Internet of Things paradigm. This paper therefore addresses this question by providing a thorough analysis of both security requirements and infrastructural requirements corresponding to all those TCP/IP integration strategies that can be applicable to networks with constrained computational resources.     

Intermodulation in multiple fixed beam distributed amplifier phased array antenna systems

In the recent development of phased array/distributed amplifier systems for application to mobile satellite or thin route communication systems, the intermodulation (IM) generated by the element amplifiers is spatially dispersed in such a way that some of the IM radiated energy falls outside the intended beam area. In addition, some of the IM falling inside the beam area has frequencies different from the carriers intended for that area. It is known that for fixed beam systems with frequency reuse, an average IM noise reduction of several dB can be realized. In the specific case under investigation, of four beams, nine frequencies and 12 carriers (1-33 frequency reuse factor), an IM improvement of about 2-0 dB is realized. The improvement in carrier-to-IM-noise ratio can be applied to increase system capacity, or for given capacity it can be used to reduce RF power amplifier back-off, which can be translated into a reduction of spacecraft prime power requirement. The considerable advantage gained from the multiple beam distributed amplifier approach makes it worthwhile to explore the workings of such a system and other benefits it may offer. One of the benefits is a common RF power pool for all carriers and beams, and the other is the spatial dispersion of intermodulation (IM). A satellite multiple beam pattern and the spatial dispersion of IM products are shown in Figure 1.     

La technologie asynchrone au service de la réduction d’énergie dans les systèmes embarqués

This article presents the benefits of asynchronous systems versus synchronous systems in term of energy reduction in the context of embedded systems and in particular for telecom equipments such as mobile communicating objects. The electrical consumption reduction is obtained at the hardware and software levels. The shutdown technique and the dynamic voltage scaling for asynchronous systems are studied and compared to synchronous systems. Finally, a power management policy is proposed for asynchronous microprocessors processing periodic and sporadic tasks.