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Implantable medical devices (IMDs) necessitate a consistent energy supply, commonly sourced from an embedded battery. However, given the finite lifespan of batteries, periodic replacement becomes imperative. This paper addresses the challenge by introducing a wireless power transfer system designed specifically for implantable medical devices (IMDs). It begins with a detailed analysis of the four conventional topologies. Following this, the paper provides a thorough explanation for choosing the PS topology, highlighting its advantages and suitability for the intended application. The primary parallel capacitance necessitates power from current sources; thus, a Class-E amplifier was implemented. Additionally, the selected circuit was engineered to deliver 1 W at the biocompatible resonance frequency of 13.56 MHz. The delineation of the resonance parameters hinges on multifaceted solutions, encompassing bifurcation-free operation and the attainment of peak efficiency. To ensure the feasibility of the proposed solution, a Differential-Evolution-based algorithm was employed. The results obtained from simulation-based evaluations indicated that the system achieved an efficiency exceeding 86%. This efficiency level was maintained even in the face of frequency fluctuations and variations in the coupling between the coils, thereby ensuring stable operational performance. This aligns seamlessly with the specified application prerequisites, guaranteeing a feasible and reliable operation. [ABSTRACT FROM AUTHOR]

The work consists of the development of a market-friendly 600 W photovoltaic battery-less water pumping system. The system is composed of four 280 Wp solar panels, an auxiliary 10 W solar panel, a three-phase converter and a ½ horsepower (hp) submersible water pump. The electronic stage involves a resonant DC-DC converter in series with a voltage source three-phase inverter. The novelties of this work are related to the use of a resonant DC-DC converter with fixed duty-cycle and frequency for water pumping application, the use of Silicon Carbide Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) for solving converter startup issues, and the use of a constant voltage maximum power tracking (MPPT) algorithm with auxiliary panels. The work displays the design of the converter, simulation and experimental results, discussions, and cost evaluation. The feasibility of the system is studied for the water requirements of a beef cattle farm in Brazil. [ABSTRACT FROM AUTHOR]

This paper presents novel current sensorless maximum-power point-tracking (MPPT) algorithms based on compensators/controllers and a single-input voltage sensor. The proposed MPPTs eliminate the expensive and noisy current sensor, which can significantly reduce the system cost and retain the advantages of the widely used MPPT algorithms, such as Incremental Conductance (IC) and Perturb and Observe (P&O) algorithms. Additionally, it is verified that the proposed algorithms, especially the proposed Current Sensorless V based on PI, can reach outstanding tracking factors (TFs) such as the IC and P&O based on PI algorithms. In this sense, the insertion of controllers inside the MPPT gives them adaptive characteristics, and the experimental TFs are in the remarkable range of more than 99%, with an average yield of 99.51% and a peak of 99.80%. [ABSTRACT FROM AUTHOR]

This work proposes a differential evolution algorithm to control a vehicle-to-grid (V2G) system based on photovoltaic generation and energy cost curves, and constraints associated with the power converters' operation, battery charging strategy, and initial budgets. The algorithm is designed to trade off the batteries' state of charge and the profits gained from selling energy to the grid. To achieve this balance, a fuzzy controller is employed and acts based on forecasts of the photovoltaic generation and the cost of electricity, within prediction windows of 120 min, adapting the batteries' rate of charging or discharging. Simulation results show that for different curves and different initial budgets, the target state of charge is reached at the end of the time horizon. By evaluating the proposed scheme under different scenarios, the algorithm's performance is proven to be suitable for future practical deployment. [ABSTRACT FROM AUTHOR]

A polymorph of glycyl-L-alanine HI.H2O is synthesized from chiral cyclo-glycyl-L-alanine dipeptide. The dipeptide is known to show molecular flexibility in different environments, which leads to polymorphism. The crystal structure of the glycyl-L-alanine HI.H2O polymorph is determined at room temperature and indicates that the space group is polar (P21), with two molecules per unit cell and unit cell parameters a = 7.747 Å, b = 6.435 Å, c = 10.941 Å, α = 90°, β = 107.53(3)°, γ = 90° and V = 520.1(7) Å3. Crystallization in the polar point group 2, with one polar axis parallel to the b axis, allows pyroelectricity and optical second harmonic generation. Thermal melting of the glycyl-L-alanine HI.H2O polymorph starts at 533 K, close to the melting temperature reported for cyclo-glycyl-L-alanine (531 K) and 32 K lower than that reported for linear glycyl-L-alanine dipeptide (563 K), suggesting that although the dipeptide, when crystallized in the polymorphic form, is not anymore in its cyclic form, it keeps a memory of its initial closed chain and therefore shows a thermal memory effect. Here, we report a pyroelectric coefficient as high as 45 µC/m2K occurring at 345 K, one order of magnitude smaller than that of semi-organic ferroelectric triglycine sulphate (TGS) crystal. Moreover, the glycyl-L-alanine HI.H2O polymorph displays a nonlinear optical effective coefficient of 0.14 pm/V, around 14 times smaller than the value from a phase-matched inorganic barium borate (BBO) single crystal. The new polymorph displays an effective piezoelectric coefficient equal to d e f f = 280   p C N − 1 , when embedded into electrospun polymer fibers, indicating its suitability as an active system for energy harvesting. [ABSTRACT FROM AUTHOR]

This work compares the performance of two embedded FPGA controllers that can be used in Active Parallel Power Filters (APPF). Both controllers are validated through the FPGA-in-the-loop (FIL) technique, the algorithm's synthesis is accomplished using the Quartus II® platform, and the board used is from Altera®—Cyclone IV DE2-115. The main difference between the controllers resides in the power theories used to obtain the currents for compensation. The results confirm that the FPGA is a suitable digital device for the parallel operation of multiple compensators and calculation stages, being a viable solution for the requirements imposed in the control of APPF. Furthermore, the effectiveness of the FIL technique for validating the operation of digital circuits and control systems is also confirmed. Finally, a comparison between the processing costs of each of the implemented power theories is presented to guide novel proposals. [ABSTRACT FROM AUTHOR]

This paper describes the use of a Cascaded H-Bridge Multilevel Inverter to deal with the problem of partial shading in a photovoltaic system connected to the grid. Combined with the topology, it proposes the use of a virtual synchronous generator for power sharing between photovoltaic arrays and to ensure the connection to the power grid even in extreme shading situations with no power buffer. The experimental results demonstrate the feasibility of the strategy adopted and the limitations to overcome. [ABSTRACT FROM AUTHOR]

This article presents a study of the sampling rate effect on electrical power measurements whose definitions are based on the Conservative Power Theory (CPT). The definitions of active power and reactive power of the CPT were applied in the MATLAB® software by varying the sampling rate and using a digital power meter as a reference. The measurements were performed in scenarios with linear and non-linear loads. Due to the usage of an integral in the CPT calculus, an error was verified associated with the reactive power being inversely proportional to the sampling rate. From the present study, it is possible to conclude that depending on the sample rate, the errors associated with the reactive power measurements are unacceptable and make the CPT implementation unfeasible. The results also presented effective information about the minimal sampling rate needed to make these errors neglected and to assist in choosing suitable microprocessors for the digital implementation of the CPT. It is worth mentioning that this paper was limited to assess how accurate the measurements of active and reactive powers were and important to highlight that the CPT has the additional contribution of dealing with distortion currents and consequently new portions of powers. For the latter, the influence of sampling rate may be crucial and new lines of investigation are motivated. [ABSTRACT FROM AUTHOR]