A High-Efficiency RF Harvester with Maximum Power Point Tracking

Gasulla, Manel; Robert, Francesc J.; Barnils, José Jordana; Ripoll-Vercellone, Edgar; Berenguer, J.; Reverter, Ferran

doi:10.3390/proceedings2131049

Cited by 2 publications

(7 citation statements)

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“…However, it was underlined that the over-voltage problem could be observed for the middle-voltage (MV) distribution system when installed PV power was being raised over a specific value. Similar discussions regarding over-voltage problems in MV and LV distribution systems can be found in [7][8][9].…”

Section: Introductionmentioning

confidence: 57%

Section: Approximating Procedures Of a Dynamic Processmentioning

confidence: 99%

“…It is easy to make sure that the error function is equal to zero when τ = 0 and τ = ∞. This circumstance is ensured by the fact that a strict solution of Equations (6) and (9) are equal in two extreme points for τ = 0 and τ = ∞. The goal of the approximation procedure is to choose a parameter β which will guarantee in some meaning a summarized minimum of the error function in the whole range of time.…”

Section: Approximating Procedures Of a Dynamic Processmentioning

confidence: 99%

“…All PV sources are equipped with Maximum Power Point Trackers (MPPT) and DC-AC inverters transforming naturally produced directly to alternating current applicable in grids. MPPT devises which designed on different control principles [8][9][10][11][12][13][14][15][16][17][18] try to manage PV panels output parameters (panels currents and voltages) in the manner that ensures maximum achievable electric power proportional to solar irradiation. Owing to the random, distributed in time solar irradiation, all these renewable sources suffer from stochastic, erratic and poorly predictable energy generation.…”

Section: Introductionmentioning

confidence: 99%

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Selecting Ultracapacitors for Smoothing Voltage Deviations in Local Grids Fed by Transformer with Tap-Changer and Distributed PV Facilities

2019

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Widespread use of photovoltaic (PV) small and middle-power plants close or inside existing townships and villages may cause significant deviations of the grid voltage. Owing to the oscillation of solar irradiation and corresponding power flows these voltage instabilities can damage equipment and must be prevented. Designated for the voltage regulation tap-changers in distribution transformers located in a significant distance of such settlements have a sluggish response time. As a possible answer for their delay is the smoothing energy of flows in PV power installation by intermittent capacitor low-pass filtering (LPF) located near those PV facilities. The application of ultracapacitors (UC) for LPF is remarkable due to their sustainability and relatively low costs of energy storage. The parameters selection of such appliances is a well-designed procedure for linear circuits. However, DC–AC inverters in PV facilities are represented by a power (instead of a voltage) source. As a result, the total circuit including such LPF becomes a non-linear and its transient process and consequently, its efficiency is difficult to assess requiring each time of development the UC storage an application complex numerical procedure. Engineers are usual to work with linear circuits that are describing fine by a time constant is designated as a multiplication of a capacitance times load equivalent resistance. In the case of PV DC–AC inverters, such an approach can be applied as well but a value of a time constant should be corrected. Considering a significant cost of UC storage, the non-optimal selection of a correcting coefficient may cause considerable loses. Submitted in the presented article is an original approximation procedure giving an efficiently approachable technique to select correcting coefficient for describing non-linear dynamic process by its linear analog. This way the development low-pass UC filtering in electrical systems with PV plants becomes more efficient and simpler task.

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Section: Introductionmentioning

confidence: 57%

Section: Approximating Procedures Of a Dynamic Processmentioning

confidence: 99%

Section: Approximating Procedures Of a Dynamic Processmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Selecting Ultracapacitors for Smoothing Voltage Deviations in Local Grids Fed by Transformer with Tap-Changer and Distributed PV Facilities

2019

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“…However, the derived expressions, which in some cases seek to model the rectenna output as an equivalent Thévenin circuit, are rather complex and may require additional simulations or extensive calculations, which hide the influence of the different parameters of the rectenna on its performance [12,18,26,27,28]. At the other extreme, the Thévenin parameters are sometimes inferred by experimental characterization [25,29,30,31,32]. However, in these cases no relationship with the rectenna parameters is established.…”

Section: Introductionmentioning

confidence: 99%

A Compact Thévenin Model for a Rectenna and Its Application to an RF Harvester with MPPT

Gasulla

Ripoll-Vercellone

Reverter

2019

Sensors

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This paper proposes a compact Thévenin model for a rectenna. This model is then applied to design a high-efficiency radio frequency harvester with a maximum power point tracker (MPPT). The rectenna under study consists of an L-matching network and a half-wave rectifier. The derived model is simpler and more compact than those suggested so far in the literature and includes explicit expressions of the Thévenin voltage (Voc) and resistance and of the power efficiency related with the parameters of the rectenna. The rectenna was implemented and characterized from −30 to −10 dBm at 808 MHz. Experimental results agree with the proposed model, showing a linear current–voltage relationship as well as a maximum efficiency at Voc/2, in particular 60% at −10 dBm, which is a remarkable value. An MPPT was also used at the rectenna output in order to automatically work at the maximum efficiency point, with an overall efficiency near 50% at −10 dBm. Further tests were performed using a nearby transmitting antenna for powering a sensor node with a power consumption of 4.2 µW.

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A High-Efficiency RF Harvester with Maximum Power Point Tracking

Cited by 2 publications

References 9 publications

Selecting Ultracapacitors for Smoothing Voltage Deviations in Local Grids Fed by Transformer with Tap-Changer and Distributed PV Facilities

Selecting Ultracapacitors for Smoothing Voltage Deviations in Local Grids Fed by Transformer with Tap-Changer and Distributed PV Facilities

A Compact Thévenin Model for a Rectenna and Its Application to an RF Harvester with MPPT

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