0000000000266054
AUTHOR
José A. Carrasco
A three domain controller for a high frequency high power four quadrant power converter for superconducting magnets
The paper describes the implementation of a controller that orchestrates the functioning of three subsystems that implement a high energy converter (/spl plusmn/1500 A, /spl plusmn/15 V) that supplies a superconducting magnet to be used in particle accelerators. The performance of the whole system, in accordance to specifications, is documented with experimental results.
Isolated two-stage passive PFC rectifier for the Radioisotope Stirling Generator
This paper describes an isolated, passive power factor correction rectifier devised for low-voltage, large-inductance, single-phase alternator, like the one used in the Radioisotope Stirling Generator. The power converter splits into two independent stages, the front-end rectifier corrects the power factor by adding a series capacitor in the AC line. Further, the rectifier, thanks to the alternator inductance, behaves as a constant-current source that powers a current-fed, zero voltage and zero current switching push-pull stage. This approach takes advantage of all parasitic elements to increase power density while keeping simple and reliable. Full description and analysis is given as well …
High-Efficiency Regulation Method for a Zero-Current and Zero-Voltage Current-Fed Push–Pull Converter
A new high-efficiency regulation method for a zero-current and zero-voltage current-fed push-pull converter is presented. The method proposed is based on the use of a controlled transformer as a post-regulator, which adds or subtracts an additional voltage to the output filter of the converter. An auxiliary regulator, which only handles a percentage of the output power, controls this transformer, and therefore, results in much higher efficiency than a normal preregulator would have. The novelty of the presented converter is that regulation is achieved without affecting the zero-voltage and zero-current switching in any working conditions. Small- and large-signal models of the converter have…
The Sequential Switching Shunt Maximum Power Regulator and its Application in the Electric Propulsion System of a Spacecraft
This paper describes a baseline solution of a Power Conditioning and Distribution Unit (PCDU) for Electrical Propulsion (EP) systems. The solution adopted uses two high efficiency, low-mass power regulators; a solar array regulator (SAR) based on the classical Sequential Switching Shunt Regulator with Maximum Power Point Tracking (MPPT) capability followed by a step-up converter to achieve the desired regulated bus voltage. This paper focuses on the first part of the PCDU, the Sequential Switching Shunt Maximum Power Regulator (S3MPR). This electrical architecture has been adapted and recently proposed for the Electric Propulsion power system of the European and Japanese Mercury Mission (Be…
A new bi-faced log periodic printed antenna
In this paper, a new design of a broadband planar printed antenna based on the academic log periodic antenna is presented. The antenna consists of a series of printed dipoles, distributed on both faces of the substrate. Some configurations are explored, with a different number of printed dipoles. These are designed, simulated, fabricated, and measured. The calculated and measured return losses and radiation patterns are presented. The utility of the proposed antenna associated with its frequency bandwidth is better than 80%. The measured absolute gain is 6.5 dBi, and the front-to-back ratio is around 8 dB. The presented antenna should find wide applications in wireless communication systems…
Evaluation of Gallium Nitride Transistors in Electronic Power Conditioners for TWTAs
The aim of this paper is to evaluate the benefits of replacing Si Mosfets transistors with enhancement mode GaN transistors in a Half-Bridge Zero Voltage and Zero Current Switching Power Switching Converter (ZVZCPS). This converter is usually used as power supply of the travelling-wave tube amplifiers (TWTAs) in aerospace applications. In this paper, firstly the converter is theoretically analyzed, obtaining its operation, losses and efficiency equations, these equations are used to obtain optimizations maps based on the main system parameters. In this way, the ideal design parameters can be visually obtained. These optimization maps are the key to quantify the potential benefits of GaN tra…
Real time estimation of photovoltaic modules characteristics and its application to maximum power point operation
In this paper, an approximate curve fitting method for photovoltaic modules is presented. The operation is based on solving a simple solar cell electrical model by a microcontroller in real time. Only four voltage and current coordinates are needed to obtain the solar module parameters and set its operation at maximum power in any conditions of illumination and temperature. Despite its simplicity, this method is suitable for low cost real time applications, as control loop reference generator in photovoltaic maximum power point circuits. The theory that supports the estimator together with simulations and experimental results are presented.
New Power Conditioning System for Battery-free Satellite Buses with Maximum Power Point Tracking
The purpose of this paper is describe a new conception of Power Conditioning Unit (PCU) developed to fulfill the requirements of BepiColombo Electronic Propulsion module. This load bus has very tough specification especially regarding transient response during total load switch-off ("beam out") which has to be less than 2% of the bus voltage. The conception we propose, is the new Sequential Switching Shunt Maximum Power Regulator (S3MPR) consisting in a S3R, to keep the SA voltage at its Maximum Power Point (MPP) followed by a Boost regulator to produce a constant 100V to supply the Electronic Propulsion (EP). This concept may also be of interest for other future missions involving high pow…
Hydrogen back-up power system with photovoltaic direct energy transfer regulation and interleaved boost for space applicattions
This work details a power conditioning unit for photovoltaic/hydrogen based energy systems in space applications. The power conversion techniques applied are similar to the ones used on photovoltaic/battery space power systems. A direct energy transfer photovoltaic regulator is devised for feeding two outputs; the first output corresponds to the main unregulated battery bus and the second output sets a power path to feed an electrolyser. A modular fuel cell converter completes the system and operates when photovoltaic energy is not available or load demand exceeds the generated photovoltaic power, providing electrical power from a fuel cell. An ancillary battery, located in the main bus, di…
Benefits and Drawbacks of A High Frequency Gan Zvzcps Converter
This paper presents the benefits and drawbacks of replacing the traditional Si Mosfets transistors with enhancement mode GaN transistors in a Half-Bridge Zero Voltage and Zero Current Switching Power Switching (ZVZCPS) converter. This type of converters is usually used as Electronic Power Converters (EPC) for telecommunication satellites travelling-wave tube amplifiers (TWTAs). In this study, firstly the converter is theoretically analysed, obtaining its operation, losses and efficiency equations. From these equations, optimizations maps based on the main system parameters are obtained. These optimization maps are the key to quantify the potential benefits of GaN transistors in this type of…
A low-cost compact uniplanar Quasi–Yagi printed antenna
A low cost directive uniplanar broadband printed Quasi–Yagi antenna design is presented. As a particular realization, some prototypes have been designed to operate in the 2.45 GHz band. They have been then modeled, fabricated onto standard printed circuit dielectric substrate and tested successfully. For the design and the modeling processes, we have make use of FDTD based in-house developed algorithms. The obtained bandwidth is, for all the considered cases, better than 15%. The main radiation characteristics are 2–5.5 dBi gain, depending on the number of director elements, and better than 25 dB front-to-back ratio. Overall antenna size was, in any case lesser than 1 λ × 0.5 λ. © 2008 Wile…
A high-efficiency regulation technique for a zero-voltage zero-current power switching converter
This paper describes the application of a new regulation technique to a resonant converter that features zero-voltage (ZV) and zero-current (ZC) switching and works at constant frequency and duty cycle. The regulator utilizes the concept of regulating only a percentage of the total power in a bidirectional manner, thus allowing the converter to be optimized for both mass and efficiency. The proposed regulation technique has a wide range of applicability to almost all types of power converters or inverters that utilize a transformer to produce an isolated output. By using the concept of addition or subtraction of AC voltages, a fully regulated output voltage is achieved. The resultant effect…
Design of Yagi-like printed antennas for WLAN applications
A directive broadband printed Yagi-like antenna design is presented. We have focused on the 2.45 GHz WLAN band, at which some designs have been carried out. For the design and the modelling processes, we made use of FDTD based in-house developed algorithms. Some selected prototypes have then been fabricated onto a low-cost printed circuit board dielectric substrate and tested successfully. Bandwidths higher than 10% and moderate to high (>7 dBi) gains can be obtained this way. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2174–2178, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22655
Cover Feature: Boosting the Supercapacitive Behavior of CoAl Layered Double Hydroxides via Tuning the Metal Composition and Interlayer Space
The Cover Feature illustrates the improvement in the supercapacitive performance of CoAl layered double hydroxides (LDHs) after enlarging their interlayer space with anionic surfactants. This enhancement in the energy storage is ascribed to the increase in the electrochemical surface area (ECSA), the higher electrolyte diffusion, and the partial aluminum dissolution. PNICTOCHEM 804110 (G.A.) CIDEGENT/2018/001 Portada de revista, actividad de difusión.