Evidence map›Paper›PMID 33809337›Full record

ArticleSensors (Basel, Switzerland)2021

Simultaneous Power Feedback and Maximum Efficiency Point Tracking for Miniaturized RF Wireless Power Transfer Systems.

Sebastian Stoecklin, Adnan Yousaf, Gunnar Gidion, Leonhard Reindl, Stefan J Rupitsch

Abstract read
In one paragraph

Article in Sensors (Basel, Switzerland), 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 4 papers.

0numbers the graph read from it
0cells of the map it votes in
4citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

4 citing papers in PubMed.

  1. Article
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4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors.

Sebastian StoecklinLaboratory for Electrical Instrumentation and Embedded Systems, Department of Microsystems Engineering, University of Freiburg, 79110 Freiburg, Germany.ORCID 0000-0002-0108-9065
Adnan YousafLaboratory for Electrical Instrumentation and Embedded Systems, Department of Microsystems Engineering, University of Freiburg, 79110 Freiburg, Germany.ORCID 0000-0003-4242-3055
Gunnar GidionLaboratory for Electrical Instrumentation and Embedded Systems, Department of Microsystems Engineering, University of Freiburg, 79110 Freiburg, Germany.ORCID 0000-0002-0114-9056
Leonhard ReindlLaboratory for Electrical Instrumentation and Embedded Systems, Department of Microsystems Engineering, University of Freiburg, 79110 Freiburg, Germany.ORCID 0000-0002-5068-8929
Stefan J RupitschLaboratory for Electrical Instrumentation and Embedded Systems, Department of Microsystems Engineering, University of Freiburg, 79110 Freiburg, Germany.ORCID 0000-0002-4806-9838

Funding

Albert-Ludwigs-Universität Freiburg funding programme Open Access PublishingBaden-Württemberg Ministry of Science, Research and Art funding programme Open Access PublishingDeutsche Forschungsgemeinschaft EXC1086Fritz Hüttinger Stiftung Fritz Hüttinger PhD Scholarship
6 · The paper itself

Abstract

Near-field interfaces with miniaturized coil systems and low output power levels, such as applied in biomedical sensor systems, can suffer from severe efficiency degradation due to dynamic impedance mismatches, reducing battery life of the power transmitter unit and requiring to increase the level of electromagnetic emission. Moreover, the stability of weakly-coupled power transfer systems is generally limited by transient changes in coil alignment and load power consumption. Hence, a central research question in the domain of wireless power transfer is how to realize an adaptive impedance matching system under the constraints of a simultaneous power feedback to increase the system's efficiency and stability, while maintaining circuit characteristics such as small size, low power consumption and fast reaction times. This paper presents a novel approach based on a two-stage control loop implemented in the primary-side reader unit, which uses a digital PI controller to maintain the rectifier output voltage for power feedback and an on-top perturb-and-observe controller configuring the setpoint of the voltage controller to maximize efficiency. The paper mathematically analyzes the AC and DC transfer characteristics of a resonant inductive link to design the reactive AC matching network, the digital voltage controller and ultimately the DC-domain impedance matching algorithm. It was found that static reactive L networks result in suitable efficiency levels for coils with sufficiently high quality factor even without adaptive tuning of operational frequency or reactive components. Furthermore, the regulated output voltage of the rectifier is a direct measure of the DC load impedance when using a regular DC/DC converter to supply the load circuits, so that this quantity can be tuned to maximize efficiency. A prototype implementation demonstrates the algorithms in a 40.68 MHz inductive link with load power levels from 10 to 100 mW and tuning time constants of 300 ms, while allowing for a simplified receiver with a footprint smaller than 200 mm

Indexed as

adaptive impedance matchingbiomedical systemsmaximum efficiency point trackingpower feedbackwireless microsytemswireless power transfer

Identifiers

PMID33809337
PMCPMC8000423

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.