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This paper analyzes a DC-DC Dual Active Bridge (DAB) converter in order to obtain Zero Voltage Switching (ZVS) or Zero Current Switching (ZCS) in all the switches for any power range. This analysis shows the conditions that should be fulfilled to achieve ZVS and ZCS; also, it presents all the DAB switching modes that appear when a triple phase shift (TPS) modulation is used. Soft switching reduces...
The aim of this work is to study the feasibility of using the modulated frequency selective surface (FSS) as a semi-passive tag for body sensing applications at 2.45 GHz ISM band. Two prototypes are presented: a breathing sensor and a skin thermometer. The breathing sensor measures the change of the airflow temperature that is produced during respiration. The core of this sensor is a negative temperature...
This paper describes the analysis of a Dual Active Bridge converter (DAB) with soft switching and the minimum RMS current for the whole power range, using Triple Phase Shift (TPS) modulation. This analysis shows the conditions needed to have zero voltage switching (ZVS) and zero current switching (ZCS), furthermore the minimum RMS current, for all output power range. The validation has been done by...
In this paper, we present and experimentally validate a transparent signal delivery scheme using programmable sliceable bandwidth/bit rate variable transceivers (S-BVTs), for converged optical access/metro networks. A programmable transceiver based on discrete multitone (DMT) directly modulated vertical cavity surface-emitting laser (VCSEL) and direct detection (DD) is proposed to efficiently increase...
The Internet data traffic constant growth caused by the popularization of cloud services, mobile and social networks is requiring changes at the underlying networks in order to enable scalability whereas supporting a highly dynamic connectivity. Cost-effective and energy efficient solutions for flexible network subsystems are also required in order to provide future sustainable networks. In this paper,...
Plastic optical fiber (POF) has been considered as a low-cost alternative to traditional copper cabling for indoor and industrial networks. Large core step index plastic optical fibers (SI-POFs) are lightweight and robust with a safe and an easy installation. These advantages are coupled with high attenuation and dispersion that have so far limited its use to short reach and low bit rate applications...
A 1.25–2.5Gbps cost-effective transceiver based on DPSK directly phase modulated VCSEL and a heterodyne receiver with a VCSEL as LO is proposed. The proposed transmitter sensitivity is −43.5dBm for 1.25Gbps and −40.5dBm for 2.5Gbps.
The control system described in this work tunes a digital controller to achieve the specified phase margin and crossover frequency by applying a design method based on the measured frequency response of the DC/DC converter, identified by the system itself. The converter is working closed-loop from the start but with a simple controller, so the output voltage remains regulated though does not meet...
A DC-DC Dual Active Bridge (DAB) converter is analysed in this paper to obtain the conditions that allow having Soft Switching (Zero Voltage Switching or Zero Current Switching) using Triple Phase Shift modulation for any power range. Since Soft Switching reduces the switching losses, the efficiency is improved. The theoretical results are validated with a 250W prototype.
Supercapacitors, also referred as ultracapacitors, are very attractive elements to combine with batteries or fuel cells in hybrid electric vehicle applications. This is due to the fact that they present some interesting features like high power density, long life cycle and low maintenance. Accurate supercapacitors circuit models are very important because they allow optimizing the sizing and power...
Nowadays fuel cell based vehicles are considered as an environmentally friendly alternative to fossil fuel propelled vehicles. However, despite the advantages associated to fuel cells, there are a number of drawbacks that must be overcome through the design of the control strategy and the powertrain design. The use of power management strategies is intended to reduce the fuel consumption while fulfilling...
Batteries have become the most popular energy storage devices due to several features like high energy density, durability and safety. Nowadays batteries are used in fuel cells based on hybrid electric vehicles, as a zero emissions alternative transportation. In order to size and design the energy management of this type of systems, the designer requires an easy equivalent model of battery. This paper...
1Gbps full-duplex 5GHz frequency slot is proposed for uDWDM Flexible Metro-Access Networks. The cost-effective ONU transceiver is based on VCSEL as LO for coherent reception and seed for phase-modulated RSOA, providing 40.5dB of power budget.
The ICT eco-system is constantly growing in traffic demands, with emerging cloud services, mobile and social network technologies to be integrated in 5G networks. New architectural changes at the underlying networks are required to support the traffic volume growth, while providing a high level of dynamic connectivity so that applications are constantly provisioned, released, and moved around. SUNSET...
The Internet data traffic constant growth caused by the popularization of cloud services, mobile and social networks, is being stressed by the advent of 5G technologies. Hence, architectural changes are required at the underlying networks to support the expected traffic volume growth, whereas providing a highly dynamic connectivity. Cost-effective and energy efficient solutions for flexible network...
The new cloud services, the Internet of Things (IoT) and the convergence of mobile and optical networks in the 5G scenario are pushing up the traffic demand over the metro-access networks. Flexible ultra-dense Wavelength Division Multiplexing (udWDM) is a promising technology to address all these new requirements at the metro-access networks. These networks are cost sensitive, so vendors and providers...
Current trends in power distribution systems are focused on distributed architectures instead of centralized approach. Distributed architectures are more complex since interactions between converters can cause stability problems. To analyze these interactions, it is needed to know the behavior of converter impedances. Moreover, distributed power systems are typically comprised of subsystems made up...
The control system described in this work implements automatically a digital controller that achieves the highest possible cross-over frequency for the specified phase margin by applying a design method based on the measured frequency response of the DC/DC converter, identified by the system itself. The algorithms for the design, identification process and control of the converter are implemented...
A highly-scalable access architecture achieving high-user-density and enabling resiliency, centralized light-generation control, remote amplification and colorless ONU with Reflective Semiconductor Optical Amplifier (RSOA) is presented as the bridge between the already deployed Fiber-to-the-Home infrastructures and the advanced optical access networks. A techno-economical comparison of these optical...
This work describes an ultrasonic-based inspection and identification system for pieces. Given the well-known versatility and reliability of ultrasonic sensors for working in industrial environments, this system is developed for application to foundry pieces which will later be machined within the automobile industry. Starting from treatment of the ultrasonic signal reflected by an object and applying...
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