Kateryna Stoyka

Identification of ferrite core inductors parameters by evolutionary algorithms

This paper discusses the identification of Ferrite Core (FC) power inductors parameters in the real operating conditions relevant to Switch-Mode Power Supplies starting from experimental measurements. A novel method for parameters identification is proposed, based on Evolutionary Algorithms (EAs) and on the analysis of inductors non-linear behavior. Two EAs, the Genetic Algorithm and the Differential Evolution, are investigated and compared. The results of the proposed method are experimentally validated by means of a buck converter evaluation board.

Validation of inductors sustainable-saturation-operation in switching power supplies design

This paper discusses a novel method to validate Sustainable Saturation Operation (SSO) of ferrite inductors in switching power supplies design. SSO is achieved when an inductor operates in partial saturation, with ripple current, power losses and temperature rise fulfilling reliability and efficiency requirements. Achieving inductors SSO permits to reduce the size of power supplies. The method presented in this paper allows the SSO validation of inductors complying with the power supply specifications. A buck converter with Vin= 36V, Vout = 12 V, fs = 450kHz, Iout = [4, 5]A is adopted as reference case study to provide validation to the proposed approach.

A generalized numerical method for ferrite inductors analysis in high current ripple operation

Abstract Ferrite Core Power Inductors (FCPIs) operation in partial saturation offers unexplored opportunities in reducing the size of magnetic parts and the power losses in Switching Mode Power Supplies (SMPSs). This paper presents an enhanced numerical method to achieve a reliable prediction of the current ripple of FCPIs, also in partial saturation, for different conversion topologies and in whatever operating conditions. The proposed analysis includes High-Current Ripple (HCR) operations, for synchronous configurations in Continuous Conduction Mode (CCM) and for diode rectification configurations in Discontinues Conduction Mode (DCM). Relevant numerical algorithms for the reliable FCPIs current wave-shape prediction are given. Experimental verifications are performed on two boost converters in CCM and DCM to provide the validation of the proposed method.

Differential evolution algorithm-based identification of Ferrite Core Inductors saturation curves

Identification of saturation curves of Ferrite Core Inductors (FCIs) based on Differential Evolution Algorithms Processing of Experimental Measurements (DE-EMP) is discussed in this paper. It is shown that the DE-EMP approach provides more realistic data for the prediction of the peak-to-peak ripple current of FCIs compared with the information provided by manufacturers. An experimental validation of the proposed method is presented in the paper, relevant to a step-down dc-dc power converter application.

An improved algorithm for the analysis of partially saturated ferrite inductors in switching power supplies

Ferrite inductors operation in partial saturation offers unexplored opportunities in reducing the size of magnetic parts and the power losses in High-Current-Ripple Switching Mode Power Supplies (HCR SMPSs) using SiC and GaN devices. A reliable prediction of the inductor current ripple is required to exploit such opportunities. A new method for ripple analysis of saturated inductors has been recently proposed, allowing the investigation of effective SMPS design solutions with minimum size inductors. An extension of such method is herein presented, allowing design investigations for the reliable use of partially saturated ferrite inductors in HCR SMPS applications. Simulation results and experimental tests fully validate the proposed method.

Optimizing power converters with partially saturated inductors by evolutionary algorithms

This paper investigates the optimization of power converters using ferrite inductors in Sustainable Saturation Operation (SSO), performed by means of an Evolutionary Algorithm (EA). The EA is adopted to identify viable optimal solutions providing a trade-off among efficiency, inductor volume, reliability and electromagnetic emissions. Three non-isolated low-power converters of different voltage and current ratings and based on buck, boost and buck-boost topologies, have been considered for the investigation. The results show that the EA is able to identify design solutions achieving best efficiency, volume, reliability and emissions performances with inductors in SSO.

Ferrite inductor models for switch-mode power supplies analysis and design

This paper discusses some models useful to analyze ferrite inductors operating in partial saturation in Switch-Mode Power Supplies (SMPSs). Inductance vs current curves are needed to assess if the level of saturation is sustainable for the inductor, in order to achieve SMPS volume reduction. The models discussed in the paper are generated from experimental voltage and current waveforms of the inductor in SMPSs. Two dual approaches are presented, based on the local and global characterization of the inductor under small- and large-amplitude current ripple conditions. The resulting curves provide inductor current prediction in agreement with experimental data.

Photocatalytic reactor with multiphase digital control of luminous radiation

This paper investigates the effect of controlled periodic illumination by visible LEDs on the performances of a visible-light-active N-doped TiO2 photocatalyst (N — TiO2) immobilized on glass spheres for wastewater treatment, using Methylene Blue (MB) dye as a model pollutant. Different LED dimming techniques are investigated and compared, including a classical Pulse Width Modulation (PWM) technique and a novel proposed Variable-Peak PWM technique. A modulation of dimming duty-cycle is adopted as well, which allows to control the light irradiation in a new way with respect to previously used methods. Experimental results highlight the improvement in MB photocatalytic degradation process obtained by using the proposed modulation techniques.

Genetic programming approach for identification of ferrite inductors power loss models

This paper discusses the identification of power loss models of ferrite core power inductors for high-power-density Switch Mode Power Supplies. A novel method, based on Genetic Programming (GP) approach, is herein proposed. It is aimed at discovering new loss models, starting from experimental measurements and taking into account all the operating conditions, such as switching frequency, inductor current ripple and volt-microsecond product, average and rms inductor current values, even for possible inductor operation in partial saturation. The behavioral models obtained by means of the GP approach are in good agreement with experimental measurements.