This paper presents a power quality evaluation of the Class-D high-frequency power amplifier/inverter. The real, reactive, complex, apparent, distortion, and non-active powers at the input of the resonant circuit are derived and illustrated as functions of frequency. Also, the total harmonic distortion and power factor are determined. Similar analysis of the power quality at the dc input of the amplifier is given. Experimental results are given to verify the theory. It is shown that the input current of the Class-D inverter contains a significant ac component that does not contribute to the real dc input power, resulting in high distortion power, high total harmonic distortion, and poor power factor. The Class-D inverter was designed, built and tested to verify the theory.

An effective and performing hysteresis model, based on a deep neural network, with the capability to reproduce the evolution of magnetization processes under arbitrary waveforms of excitation is here presented. The proposed model consists of a standalone multi-layer feed-forward neural network, with reserved input neurons for the past values of both the input (H) and output (M), aiming at the reproduction of the storage mechanism typical of hysteretic systems. The training set has been opportunely prepared starting from a set of simulations, performed by the Preisach hysteresis model. The optimized training procedure, based on multi-stage check of the model performance, will be comprehensively discussed. The comparative analysis between the neural network-based model, implemented at low level of abstraction, and the Preisach model covers additional hysteresis processes, different from those involved in the training. The mild/moderate memory requirement and the significant computational speed make the proposed approach suitable for a future coupling with finite-element analysis.

This paper presents an analysis of an LCR second-order low-pass filter capacitor to achieve a specified ripple output voltage in Buck, forward, Zeta, and Ćuk PWM DC-DC power converters for continuous-conduction mode (CCM). Current and voltage waveforms across output filter components are derived. Using the waveform of the ac component of the output voltage, an expression for the ripple voltage is developed in terms of the filter capacitance and equivalent series resistance. The results can be used for all PWM converters with the LCR output filter, such as Buck, forward, Zeta, and Ćuk PWM DC-DC converters. Theoretical results were in good agreement with simulation and experimental results.

A model-based strategy for an efficient power supply control used in a wireless sensor network is presented. The strategy, based on Pulse-Skipping Modulation, regulates the current charging a battery, delivered by a photovoltaic source, resulting in an accurate current regulation and highly efficient power management. The strategy is implemented on a microcontroller unit and compensates for the microcontroller self-absorbed current. The modulation signal is generated through a full software interface, reducing the requirement for external components. Experimental validations, performed on a charger prototype by using a laboratory photovoltaic device simulator, proved that both regulation accuracy, regulation resolution and converter efficiency achieved are superior to the classic Pulse-Width Modulation. The approach results in a simple practical implementation, carries over the advantages of an up-to-date model for the photovoltaic device, and serves the auxiliary purpose of using the photovoltaic source as an instantaneous solar irradiance sensor.

Knowing solar irradiance value allows an optimized management of photovoltaic (PV) power plants in terms of produced energy. Unfortunately, although sensing temperature is easy, the measurement of solar irradiance is expensive. In this paper, two circuit architectures for the estimation of the solar irradiance based on simple measurements are proposed. They are thought to be part of a centralized system implemented on field programmable gate array (FPGA) for sensing and monitoring of solar irradiance in a whole PV plant. The FPGA centralized architecture could allow for a real-time irradiance mapping by exploiting information coming from several low-cost measuring circuits suitably allocated on the PV modules. Validations on real irradiance data collected by the U.S. Department of Energy's National Renewable Energy Laboratory are presented.