arXiv subjects

Juana M. Martínez-Heredia

Publications and source records attributed to Juana M. Martínez-Heredia.

5 recordsLinked to original sources

arXiv2026

Emergency Locator Transmitters in the Era of More Electric Aircraft: A Comprehensive Review of Energy, Integration and Safety Challenges

The progressive electrification of aircraft systems under the more electric aircraft (MEA) paradigm is reshaping the design and qualification constraints of safety-critical avionics. Emergency locator transmitters (ELTs), which are essential for post-accident localization and search and rescue (SAR) operations, have evolved from legacy 121.5/243 MHz beacons to digitally encoded 406 MHz systems, typically retaining 121.5 MHz as a homing signal in combined units. In parallel, the modernization of the Cospas-Sarsat infrastructure, especially MEOSAR, together with multi-constellation global navigation satellite system (GNSS) integration and second-generation beacon capabilities, is reducing detection latency and enabling richer distress messaging. However, MEA platforms impose stricter constraints on available power, thermal management, wiring density, and electromagnetic compatibility (EMC). As a result, ELT performance increasingly depends not only on the device itself, but also on its installation conditions and on the aircraft's overall electrical environment. This review summarizes the ELT architectures and activation/operational cycles, outlines key technological milestones, and consolidates the main integration challenges for MEA, with emphasis on energy autonomy, battery qualification frameworks, EMC and installation practices, and survivability-driven failure modes (e.g., antenna/feedline damage, mounting, and post-impact shielding). Finally, emerging trends include ELT for distress tracking (DT), energy-based designs, advanced health monitoring, and certification-ready pathways for next-generation SAR services are discussed, highlighting research directions that can deliver demonstrable, certifiable gains in reliability, energy efficiency, and robust integration for future electrified aircraft.

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arXiv2026

Neural Network Tuning of FSMPC for Drives

This preprint presents a neural network tuner for the finite state model predictive control of an induction motor. The tuner deals with the parameters of the controllers in the speed loop and in the stator current loop. The results are assessed using a five phase machine in an experimental setup. Data for the neural network training is obtained from the experiments using step tests.

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arXiv2026

Analog Time Multiplexing for Digital-to-Analog Conversion

The signal bandwidth of Digital to Analog Converters based on Sigma Delta Modulation is limited by speed constrains. Time-Interleaving allows coping with complexity vs. speed by replacing the original architecture by M parallel paths. These path are clocked at a frequency M times smaller and their digital outputs time multiplexed. This is then converted to analog by means of a Digital to Analog Converter clocked at the high rate. This preprint proposes that time multiplexing be performed in the analog domain. As a result robustness against dynamic effects is achieved.

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arXiv2025

A new data weighted averaging algorithm to reduce tones in the signal band

Digital/Analog converters based on sigma-delta modulation are simple and unexpensive circuits featuring a signal bandwidth limited by speed constraints. Multi-bit modulators allow balancing complexity and speed by reducing the clock frequency and increasing the number of levels in the quantizer. In this case, the multi-bit digital to analog block (DAC) can reduce the performance of the entire system. Data Weighted Averaging (DWA) methods have been proposed to reduce the vulnerability to DAC errors at the cost of spurious tones in the signal band. This work analyzes the tone producing mechanism and proposes a modification of the DWA to remove spurious tones.

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arXiv2025

Single vs Multi Vector Predictive Control of Five-phase Drives

The field of Finite State Model Predictive Control for multiphase drives has produced many contributions. Many variants of FSMPC exist, each aiming at some aspect such as complexity of the cost function, switching frequency, etc. Despite past efforts to compare different techniques, the field is still out of consensus regarding the relative merits of each one. This paper presents a new method to compare FSMPC variants. The method is based on analyzing the modulation, implicit or explicit, used by each variant. In the paper the method is used to compare single-vector state-of-the-art FSMPC with a multi-vector variant designed to cancel xy currents and simplify the cost function. The results show the strengths and weaknesses of each technique. Also, it is found that the trade-offs between figures, previously thought to concern just individual regimes, extend to the whole operating space and also can be pinpoint to each FSMPC variant. Finally, it is shown that the flexibility of the single-vector approach and its better DC-link usage makes it, arguably, superior over the multi-vector variant.

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