Ivan Luigi Spano

An improved averaged model for boost DC-DC converters

An improved averaged model suitable for boost DC-DC converters is presented in this paper. It is developed on the basis of the averaging technique with the aim of appropriately taking into account the effects of switching phenomena. Thus, two appropriate trapezoidal signals have been introduced in order to model the transient evolutions of voltages and currents of the DC-DC converter devices over both turn-on and turn-off of the switch. This enables the synthesis of an appropriate averaged model of boost DC-DC converters, which can be usefully employed in determining average voltage and current evolutions, as well as steady state average powers. The worth and effectiveness of the proposed modelling approach has been validated through a simulation study, which refers to the case of a traditional boost DC-DC converter.

A novel continuous-time equivalent circuit for boost DC-DC converters

A novel continuous-time equivalent circuit suitable for boost DC-DC converters is presented in this paper. It has been developed on the basis of the averaging technique with the aim of achieving a good ripple-free representation of the state variables of the system, whatever the converter operating mode is, i.e. Continuous Conduction Mode (CCM) or Discontinuous Conduction Mode (DCM). This goal can be achieved on condition that an appropriate PWM pattern is introduced, which enables an almost perfect matching between state variables and their corresponding equivalent ones at the start of each sampling time interval. Apart from the inductor and the capacitor, the proposed circuit consists of some equivalent input voltage and output current sources, together with several constant and/or variable resistors, which depend on converter switching signals and circuital parameters. The proposed continuous-time equivalent circuit has been validated through a simulation study, which is performed by means of the software PLECS. Simulation results highlight the worth and the effectiveness of the proposed modelling approach, over both transient and steady state operations.

Electromagnetic compatibility analysis of RFID and implantable medical devices

An analysis of Electromagnetic Interference (EMI) between a Radio Frequency Identification (RFID) device and an Implantable Cardiac Defibrillator (ICD) is presented in this paper. In particular, the analysis focuses on the effects of EMI produced by an RFID reader on ICD operation. Thus, a brief overview of both ICD and RFID devices is presented at first. Subsequently, several experimental tests are performed inside an anechoic RF chamber, which ensures an appropriate shielding against external EMI sources. As a result, the comparison among ICD operating thresholds highlights its susceptibility against the RFID device.

Performance and EMC analysis of an interleaved PFC boost converter topology

An extensive experimental analysis of a two-phase Interleaved PFC Boost converter (I-PFC-B) is presented in this paper. It aims to highlight the most important features of I-PFC-B operation, in terms of both performances and Electromagnetic Compatibility (EMC) issues. Therefore, several experimental tests are performed inside an anechoic RF chamber; in particular, Power Factor, Total Harmonic Distortion Factor, Current Crest Factor and energy efficiency are determined at different I-PFC-B output powers. Furthermore, appropriate Conducted and Radiated Emission tests are performed, in accordance with international standards, in order to reveal I-PFC-B aptitude as a non-intentional Electromagnetic Interference (EMI) source. The results highlight poor I-PFC-B performances at light loads, as well as potential conducted EMI issues within low and medium frequency ranges.

SAR evaluation of wireless antenna on implanted cardiac pacemaker

Abstract For many people, a pacemaker represents something scary because it is related to heart disease. However, that is not the main purpose of this paper, the object of the article is the technical aspect of pacemakers, in particular, their calculation of specific absorption rate values, to which the pacemaker is exposed. A pacemaker generates electrical discharges that are transferred into the heart via a lead wire and electrodes. Authors focus on the impact of Wi-Fi signal antennas on a pacemaker. A dipole antenna working in the frequency range around 5 GHz is chosen as a source of electromagnetic radiation because this kind of antennas is relatively new and it is not widely used yet. Nevertheless, it represents a potential for the future. The experiment is performed through electromagnetic simulation software called CST Microwave Studio that provides tools for SAR calculation and it allows to visualise the scatter of the resulting SAR values around the pacemaker or human torso.

An Automatic Sensing Test procedure for Implantable Cardioverter Defibrillators

An Automatic Sensing Test procedure (AST) for evaluating the sensing performances of Implantable Cardioverter Defibrillators (ICDs) is presented in this paper. AST is based on the Sensitivity Test described by the Standard CEI EN 45502-2-1 for pacemakers and consists of determining the ICD sensing thresholds at different heartbeat frequencies. Consequently, an extensive evaluation of ICD sensing performances can be achieved. AST has been implemented by means of virtual instruments developed in the Labview environment and has been validated experimentally through several tests. These have been performed inside an anechoic RF chamber. Such an environment guarantees proper shielding against external electromagnetic interferences, thus ensuring reliability and repeatability of the tests. The discussion of the results highlights the usefulness of the proposed procedure.

EM level evaluation in indoor environment

In order to show that a given set of EM sources comply with national rules on exposition, a prediction model for EM propagation is needed. For indoor environment, the test presented her show that reflections and multipath can significantly affect the field level respect to the free-space situation, which sometimes can doubles.