0000000000206775
AUTHOR
Nevoloso C.
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…
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
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.
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…
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.