0000000000206773
AUTHOR
Di Tommaso A. O.
Challenges for the Goal of 100% Renewable Energy Sources to Fit the Green Transition
The increasing penetration of Renewable Energy (RE) into the electrical market is desirable in terms of sustainability. Nevertheless, it is a challenge that all the interested actors shall address from both the technical and economical points of view. This paper provides an overview of the main challenges and solutions towards the technological transition to an electrical system with 100% renewable energy sources in terms of innovations and operative limits of the traditional systems. These innovative paradigms will also address the social impact and government policies.
Maximum Torque per Ampere Control strategy for low-saliency ratio IPMSMs
This paper deals with electrical drives employing low-saliency ratio interior permanent magnet synchronous motors. In particular, in order to help the designers choosing the best control algorithm, the performances of the Maximum Torque Per Ampere Control (MTPA) and the Field Orientation Control (FOC) are here both theoretically and experimentally assessed and compared, by using, as performance indicators, the torque-current ratio and the power losses. The tests are carried out on a low-power motor for various speeds and loads by implementing the two control strategies in a dSPACE® rapid prototyping system. The results show that the Maximum Torque Per Ampere algorithm has some appreciable a…
Mathematical formulation of pulse amplitude modulation selective harmonic elimination in multilevel three phase inverters
In this paper multilevel cascaded H-bridges (CHB) three phase inverters with 2n dc sources, n=1,2,3,... are considered and a mathematical formulation providing both 2n switching angles and dc voltage source to eliminate n+1 harmonics and their respective multiple from their output voltage waveform, is proposed. The computed angles don't depend on modulation index and the source voltages linearly vary with it. The proposed procedure finds the solution through an analytical formula that avoids to solve transcendental systems and presents very low computational cost. A lot of low order harmonics are eliminated, returning a very low total harmonic distortion (THD). Particularly for 9-level conf…
Experimental investigation on high-efficiency control algorithms for three-phase induction motors
This paper presents an experimental investigation regarding the power losses variations occurring in three-phase induction motors (IMs) as a function of the magnetization level of the machine. More in detail, the power losses identification is obtained by changing in real-time the working operating conditions of the IM drive and the IM reference flux. The sets of measurements are carried out by setting up a test bench and the obtained results confirm that the power losses occurring in induction motors can be minimized by adequately setting the direct axis current component for each IM working condition. This research represents the starting point for the conception of advanced real-time los…
Virtual Synchronous Generator: An application to Microgrid Stability
The objective of this paper is to illustrate an alternative control algorithm for power converters which have the task of introducing the energy generated by systems based on the use of renewable sources such as photovoltaic or wind power, into small-sized networks, microgrids. Virtual Synchronous Generator can operate both in parallel to the main network as well as in isolated and autonomous conditions (islanding-mode). The contribute of this work is to drive a consolidated approach, made in the time domain, in a more flexible and less time-consuming approach based on Park transformation
Experimental characterization of a proton exchange membrane fuel-cell for hybrid electric pedal assisted cycles
This paper presents a feasibility study on the prototyping of a hybrid EPAC (Electric Pedal Assisted Cycle) Through an FC-B-UC (Fuel Cell - Battery - Ultra-Capacitors) power system. Aim of this work is the characterization of a PEMFC (Proton Exchange Membrane Fuel Cell) in order to confirm its theoretical performances and to verify the possibility of its installation on an e-bike.
An accurate measurement procedure of power losses variations in electrical drives
This paper presents a general procedure for the accurate measurement of power losses variations in electrical drives. More specifically, the paper addresses the issue related to the efficiency comparison of electrical drive controlled with different control algorithms. This procedure is applied to a permanent magnet synchronous motor drive, assessing its power losses by means of two different measurement systems, each one characterized by different accuracy and cost. The comparison between these two systems is carried out for different working conditions in terms of load, speed and magnetization in order to demonstrate that the power losses variations can be accurately measured even with no…
A Simple Software-based Resolver To Digital Conversion System
In this paper, a software-based resolver to digital converter (RDC) is proposed. The hardware signal conditioning circuit is realized using common electronic components, while the algorithm can be implemented either using a microcontroller or an FPGA. Its validation and performance analysis has been carried out using an interior permanent magnet synchronous machine drive and, with comparative purposes, an LTN Servotechnik 1024 ppr incremental encoder. Tests show that the proposed RDC is characterized by a good dynamic response and precision, moreover, due to low computational demand, it can be successfully adopted without significant extra cost.
Design and Validation of a Dynamic Inductive Power Transfer System for EV Battery Charging
In this paper, a Dynamic Resonant Inductive Power Transfer (DRIPT) System for the Electric Vehicle (EV) battery charging is proposed. In particular, the aim of the work is the general design of the whole system and its validation, with particular attention to the power electronic converters and their control. For the transmitter side, a DC/AC converter is used. It is controlled through the phase-shift technique and supervised by a Zero Phase Angle detection algorithm to ensure the maximum power transfer. For the receiver side, a double conversion stage, consisting of a diode rectifier and a controlled buck converter, is provided. The system is then simulated to verify its proper design.
Cascaded H-Bridges Multilevel Inverter Drive: Active Power Analysis in Frequency Domain
The international standard IEC 61800-9-2 introduces energy efficiency classification for frequency converters or complete drive module (CDM) and provides instrumentation minimum requirements for accurate measurement of CDM input and output power valid for conventional pulse-width-modulated (PWM) voltage source inverter (VSI). This paper highlights the necessary improvements to update the standard with more detailed prescriptions according to the converter topologies and the modulation techniques adopted. In this framework, this paper address the power analysis in the frequency domain of a cascaded H-bridges-multilevel inverter (CHBMI) in an interior permanent magnet synchronous motor (IPMSM…
Enhanced modulation strategy for 7-level voltage waveform in asymmetrical 5-level Cascaded H-Bridge Inverters
The CHBMI performance optimization can be reached both with hardware and software solutions. Generally, asymmetrical configurations allow the extension of the voltage levels number and the implementation of an innovative modulation strategy allows for improving the performance in terms of harmonic distortion and conversion efficiency. This work is devoted to the development of a modulation strategy that allows improving the performance of an asymmetrical single-phase five-level Cascaded H-Bridge Inverter generating a 7-level voltage waveform. Thus, a digital approach and corresponding digital functions are presented. Subsequently, the impact of the dead time and the influence on the voltage…
A Configuration of 3-phase Traction Inverter Employing {SiC} Devices
In the scenario of a more and more sustainable society, an increasing electrification in different fields, such as mobility and industrial applications, is foreseen in the next decades. As far as power electronics is concerned, a challenging perspective is represented by achieving higher and higher switching frequencies while maintaining high voltage and low power losses. To do that, emerging semiconductor technologies are supposed to be increasingly employed, as well as innovative topologies of connections among switching devices. Among them, the cascode configuration can notably contribute to achieve high levels of dV/dt without losing efficiency. In this paper, a 3-phase Pulse Width Modu…
Electron structure, ultra-dense hydrogen and low energy nuclear reactions
In this paper, a simple Zitterbewegung electron model, proposed in a previous work, is presented from a different perspective based on the principle of mass- frequency equivalence. A geometric- electromagnetic interpretation of mass, relativistic mass, De Broglie wavelength, Proca, Klein- Gordon, Dirac and Aharonov- Bohm equations in agreement with the model is proposed. A non-relativistic, Zitterbewegung interpretation of the 3.7 keV deep hydrogen level found by J. Naudts is presented. According to this perspective, ultra-dense hydrogen can be conceived as a coherent chain of bosonic electrons with protons or deuterons located in the center of their Zitterbewegung orbits. This approach sug…
Investigation about selective harmonic elimination in unbalanced multilevel inverters
In this paper 5 and 7 levels cascaded H-bridges inverters are considered, feeding by unequal dc voltage sources. The effect of these unbalancing operation is examined concerning harmonic analysis and total harmonic distortion of the output voltages. The system of equations, obtained by the expansion in the Fourier series of phase output voltage, is solved by applying a method of graphic solution that allows obtaining the switching angles able to eliminate the lower order harmonics.