Search results for "computers"
showing 10 items of 3243 documents
Predicting the Batteries' State of Health in Wireless Sensor Networks Applications
2018
[EN] The lifetime of wireless sensor networks deployments depends strongly on the nodes battery state of health (SoH). It is important to detect promptly those motes whose batteries are affected and degraded by ageing, environmental conditions, failures, etc. There are several parameters that can provide significant information of the battery SoH, such as the number of charge/discharge cycles, the internal resistance, voltage, drained current, temperature, etc. The combination of these parameters can be used to generate analytical models capable of predicting the battery SoH. The generation of these models needs a previous process to collect dense data traces with sampled values of the batt…
Adapting power consumption to performance requirements in a MSP430 microcontroller
2005
Microcontroller based low power systems using batteries must run at low clock frequencies with short activity periods to extend battery life. These constraints reduce the microcontroller computational capabilities and limit the complexity of algorithms that can be used. New microcontroller architectures, as the Texas Instruments MSP430 family, allow to adapt power consumption to application performance requirements combining several low power modes with the capability of switching the clock frequency dynamically. A complete characterization of power consumption vs. performance has been obtained for the MSP430. A method to determine the range of clock frequencies that meets a consumption and…
Characterisation of a commercial automotive lithium ion battery using extended Kalman filter
2013
This paper presents a extented Kalman filter based on a dynamic model of a commercial lithium ion battery pack in automotive applications, and experimental data are collected using the Noao. This vehicle is an electric track with range extender, which has been developed and produced by the association Pole de Performance de Nevers Magny-Cours (PPNMC). This model has been developed with MATLAB/Simulink to investigate the output characteristics of lithium-ion batteries. It incorporates I-V performance of the battery, battery capacity fading, temperature effect on battery performance, and the battery temperature rise. This estimation technique is used in order to estimate some parameters, whic…
Efficient contactless power transfer system for EVs
2016
Based on the inductive power transfer (IPT), the contactless approach allows safe and comfortable operations of battery charging for Electric Vehicles (EVs). In this paper, a contactless system particularly suitable for E-bike battery charging is proposed. A practical realization of the system has been carried out, aiming at the system evaluation in terms of working and efficiency. Through a phase shift modulation, a power regulation has been implemented. The target power level is 100 W.
An efficient wireless power transfer prototype for electrical vehicles
2017
Based on the inductive power transfer (IPT), the contactless approach allows safe and comfortable operations of battery charging for Electric Vehicles (EVs). In this paper, a contactless system particularly suitable for E-bike battery charging is proposed. A practical realization of the system has been carried out, aiming at the system evaluation in terms of working and efficiency. Through a phase shift modulation, a power regulation has been implemented. The target power level is 100 W.
Battery technologies for electric vehicles
2017
This chapter gives a brief overview of the following types of vehicles: battery electric vehicle (BEV), plug-in hybrid electric vehicle (PHEV), and hybrid electric vehicle (HEV). It then provides a comprehensive summary of the electrochemical energy storage including Ni-MH battery, Li-ion battery, and advanced rechargeable battery. Battery chemistry is explained in a detailed manner including an abbreviated modelling approach. Also, the issues of battery-charging method, management, and monitoring are addressed. The chapter concludes with a discussion on battery cell voltage balancing and temperature monitoring in addition to the battery state-of-charge (SOC) estimation.
Near field improvements of stochastic collaborative beamforming in wireless sensor networks
2020
Wireless sensor networks (WSN) are groups of small devices that contain a microcontroller in which a large number of sensors can be added. They transmit data and communicate to each other in the ISM band, standard IEEE 802.15.4, exchanging packets using a multi-hop routing. These devices are named motes and are nodes of the WSN. They are very simple and easy to program, powered by batteries of 1.5Volts (AA and AAA). The nodes are autonomous elements that can be deployed implementing any type of network. In a typical deployment the nodes communicate with each other and with a master node or Base Station (BS), which in turn transmits the information to an external server, which collects the e…
A Comprehensive Survey on Cooperative Relaying and Jamming Strategies for Physical Layer Security
2019
Physical layer security (PLS) has been extensively explored as an alternative to conventional cryptographic schemes for securing wireless links. Many studies have shown that the cooperation between the legitimate nodes of a network can significantly enhance their secret communications performance, relative to the noncooperative case. Motivated by the importance of this class of PLS systems, this paper provides a comprehensive survey of the recent works on cooperative relaying and jamming techniques for securing wireless transmissions against eavesdropping nodes, which attempt to intercept the transmissions. First, it provides a in-depth overview of various secure relaying strategies and sch…
Practical Considerations in the Implementation of Collaborative Beamforming on Wireless Sensor Networks
2017
Wireless Sensor Networks (WSNs) are composed of spatially distributed autonomous sensor devices, named motes. These motes have their own power supply, processing unit, sensors and wireless communications However with many constraints, such as limited energy, bandwidth and computational capabilities. In these networks, at least one mote called a sink, acts as a gateway to connect with other networks. These sensor networks run monitoring applications and then the data gathered by these motes needs to be retrieved by the sink. When this sink is located in the far field, there have been many proposals in the literature based on Collaborative Beamforming (CB), also known as Distributed or Cooper…
Relay selection in FDD amplify-and-forward cooperative networks
2017
In this paper, the problems of relay selection and distributed beamforming are investigated for bi-directional dual-hop amplify-and-forward frequency-division duplex cooperative wireless networks. When using individual per-relay maximum transmission power constraint, it has been proven that the relay selection and beamforming optimization problem becomes NP hard and requires exhaustive search to find the optimal solution. Therefore, we propose a computationally affordable sub-optimal multiple relay selection and beamforming optimization scheme based on the l1 norm squared relaxation. The proposed scheme performs the selection for the two transmission directions, simultaneously, while aiming…