C. Cavallaro

Electrolyser in H2 Self-Producing Systems Connected to DC Link with Dedicated Phase Shift Converter

In this paper the converter requirements for an optimum control of an electrolyser linked with a DC bus are analyzed and discussed. The hydrogen generating device is part of a complex system constituted by a supplying photovoltaic plant, the grid and a fuel cell battery. The characterization in several operative conditions of an actual industrial electrolyser is carried out in order to design and optimize the DC/DC converter. A dedicated zero voltage switching DC/DC converter is presented and simulated inside the context of the distributed energy production and storage system. The proposed supplying converter gives a stable output voltage and high circuit efficiency in all the proposed simulated scenarios. The adopted DC/DC converter is realized in a full-bridge topology with phase-shift PWM technique in order to achieve zero voltage switching for the power switches and to regulate the output voltage. Furthermore, in order to increase the converter efficiency at the transformer secondary side, a current doubler rectifier is implemented.

A Phase-Shift Full Bridge Converter for the Energy Management of Electrolyzer Systems

The purpose of this work has been the development of the supplying system for an industrial electrolyzer. The hydrogen generating device is part of a complex system constituted by a supplying photovoltaic plant, the grid and a fuel cell battery. The main aim of this electrical system is the hydrogen storage devoted to the suitable load supplying in order to obtain an optimum load profile in case of domestic consumers. The converter is linked to a maximum power point tracking (MPPT) algorithm which enables a converter to extract the maximum power from the photovoltaic plant. The energy is supplied to the electrolyzer or the storage system according to the load profile. A phase-shift control strategy has been adopted and the ZVS at turn on driving strategy, in order to increase the efficiency and thus lowering the power consumption for the whole system. The system has been developed looking for the realization of a dedicated integrated circuits utilization where the control strategy has been implemented.

Smart photovoltaic UPS system for domestic appliances

The paper deals with an innovative system achieving an auxiliary source of energy supply from photovoltaic solar system, which operates in case of blackouts by providing a set of loads determined by the continuity of service during the absence of power supply by the network. The system is designed mainly suitable for use in the field of home appliances. It also finds additional possible uses in medical and/or in industries where the continuity of service plays a fundamental role for safety. The proposed solution is based on a photovoltaic system for stand-alone coupled with a conventional UPS (Uninterruptible Power Supply). A key role is played by an intelligent control that handles both the charge of a suitable stack of batteries, and the electrical loads connected to UPS. UPS enables loads to be supplied by assigning them an index of priority established by the operator depending on its importance or safety.

A voltage sensing approach for a maximum power tracking in integrated photovoltaic applications

The main aim of this paper is the analysis and experimental evaluation of the performance of a photovoltaic power plant controlled by a dedicated algorithm. This is devoted to the search of the maximum power point during the energy conversion of the photovoltaic panels. The proposed approach uses a control strategy that does not requires the current sensing, which is a main cause of noises, errors and delays during the step by step detection of the working point. Modeling of both the power source and the switching converter is a key step for the implementation of the voltage sensing tracking routine. The proposed algorithm has been implemented in a 8-bit microcontroller. A SEPIC converter topology is the core of the experimental workbench that has been realized with 100W as rated power. The experimental analyses show a very low noise in the signal sensing and a very fast response of the whole system. This is able to reach suitable working points in less than 100ms after the a perturbation occurred. The achieved results led to consider this set-up appropriate for a system that is composed by a PV module and an integrated DC-DC converter.

Energy harvesting in roped elevators

In civil buildings, large part of energy consumption of common service is related to lift apparatus operations. Considering the huge diffusion of roped elevators and their reciprocating operating mode, a critical evaluation of energy streams has been done using an accurate model specially developed. Thus, a retrofit kit has been studied and designed able to store the energy during the generating mode of the electrical machine and to recover it back in motor operation. Finally, a comprehensive evaluation of the saved energy parameterized with the numbers of passengers and lift duty cycle is presented, as well as the kit cost estimation and pay-back time.

Load priority control strategy for SPV-UPS system

The paper deals with a smart load priority control strategy for Photovoltaic Uninterruptible Power Supply (PV-UPS) system. This hybrid uninterruptible power supply system achieves an auxiliary source of energy supply from photovoltaic modules, which operates in case of blackouts by providing a set of loads determined by the continuity of service during the absence of power supplied by the AC network. The proposed system is mainly designed for the field of home appliances. The proposed solution is based on a stand-alone photovoltaic system with a conventional UPS. A key role is played by an intelligent control strategy that handles both the charge of a suitable stack of batteries and the electrical loads connected to UPS. UPS enables loads to be supplied by assigning them an index of priority established by the operator, depending on their importance or safety.

CAD analysis on electrical field of load break switch suitable for medium voltage applications

The proposed paper deals with the investigation of the electrical field distribution on an actual 36 kV gas insulated three phase load break switch application. The proposed medium voltage switch characteristics and applications are described and evaluated. In particular the switchgear characteristics and performances are focused. An accurate static analysis of the electrical field distribution in both the switchgear and the stainless steel tank will be carried out by several simulations on a suitable model through a finite element method (FEM). The numerical analysis is applied with two dimensional dedicated software tools. The simulation results allow the correct design of the distances for both the fixed and the rotary electrical contacts. The information on the electrical field distribution allows fitting the distances of the electrical contact and pressure value of the insulation gas (SF6) injected in both the switchgear and the stainless steel tank

Monolithic cascade device in low power converter applications with wide range input voltage

An improved converter for low power and wide range input voltage, which is particularly suitable for auxiliary uses in three-phase grid of industrial applications, is studied. A flyback quasi-resonant topology has been chosen, which offers the good characteristics of high voltage operations and good efficiency. A comparison is performed among available kinds of semiconductor devices with good peculiarities for the specific topic. In particular the analysis focuses on MOSFET and cascode devices. The latter component shows good characteristics in this specific application of high voltage operations at high switching frequency and low power. The converter design is described with a particular attention to the crucial instances of switching and conduction losses and the thermal dissipation. Moreover the quasi-resonant operation mode has been exploited in order to improve the effectiveness of the solution adopted. The zero voltage operation is obtained by a gate driver chip specifically designed to build offline quasi-resonant zero voltage switching in flyback converters. Finally, several experimental tests are considered and specifically described

Active boat roll stabilization via efficient PMSM actuators

The paper deals with the development of a mathematical model of an active anti-rolling system for yachts and luxury boats, tailored around a pair of fin stabilizers driven by Permanent Magnet Synchronous Motor drives. Based on such a model, dynamic and energetic performance of the stabilizing system can be analyzed either with the boat cruising and the boat at anchor. The developed model can be exploited to tune the parameters of the roll control system, a task often accomplished on the field, and to design optimal boat cruise control algorithms.

Smart load priority control for a SPV-UPS

The paper deals with a smart load priority control strategy for Photovoltaic Uninterruptible Power Supply (PV-UPS) system. This hybrid uninterruptible power supply system achieves an auxiliary source of energy supply from photovoltaic modules, which operates in case of blackouts by providing a set of loads determined by the continuity of service during the absence of power supplied by the AC network. The proposed system is mainly designed for the field of home appliances. The proposed solution is based on a stand-alone photovoltaic system with a conventional UPS. A key role is played by an intelligent control strategy that handles both the charge of a suitable stack of batteries and the electrical loads connected to UPS. UPS enables loads to be supplied by assigning them an index of priority established by the operator, depending on their importance or safety.