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 suggests a possible role of ultra-dense hydrogen in some aneutronic and many-body low energy nuclear reactions. © 2019 ISCMNS. All rights reserved

A General Mathematical Formulation for the Determination of Differential Leakage Factors in Electrical Machines with Symmetrical and Asymmetrical Full or Dead-Coil Multiphase Windings

This paper presents a simple and general mathematical formulation for the determination of the differential leakage factor for both symmetrical and asymmetrical full and dead-coil windings of electrical machines. The method can be applied to all multiphase windings and considers Görges polygons in conjunction with masses geometry in order to find an easy and affordable way to compute the differential leakage factor, avoiding the adoption of traditional methods that refer to the Ossanna's infinite series, which has to be obviously truncated under the bound of a predetermined accuracy. Moreover, the method described in this paper allows the easy determination of both the minimum and maximum values of the differential leakage factor, as well as its average value and the time trend. The proposed method, which does not require infinite series, is validated by means of several examples in order to practically demonstrate the effectiveness and the easiness of application of this procedure

Rotor bar pre-fault detection in the squirrel cage induction motors

The paper deals with a diagnosis technique to detect and monitor incipient faults in the rotor bars of squirrel gage induction motors. The failure mode analysis is performed monitoring the motor axial vibrations. To accomplish the task, the authors present a mathematical model that allows relating the occurrence and the severity of the faults to the presence and the magnitude of some frequency components of the axial vibration spectrum. To validate the proposed approach, the results obtained by applying the mathematical model are compared with the ones obtained by experimental tests done on both healthy and faulty motors

A Novel, Simple and Flexible Fault-Tolerant Control Algorithm for Multiphase Electrical Machine Operation Under Open Circuit Faults

This paper presents a novel and simple procedure for the determination of a Fault-Tolerant Algorithm (namely FTA) for the adequate working operation of an electric machine equipped with a general m-phase winding under possible open circuits occurring in some of its phases. The FTA is firstly theoretically derived from the analysis of the magnetic field distribution in polyphase systems, then simulated through finite-element analysis and finally implemented via software for real-time validation. The effectiveness of the proposed procedure is confirmed through experimental tests on a laboratory setup. Key contributions include the flexibility of the algorithm, which can be applied to any m-phase electric machine with various winding configurations. Both the obtained FEA and experimental results demonstrate that the proposed control algorithm can be easily used and applied in electric drives supplied by m-phase motors under fault conditions without significantly affecting the magnetic performance of the whole system and ensuring the continuity of operation even in the presence of faults

A Novel Multi-Objective Finite Control Set Model Predictive Control for IPMSM drive fed by a Five-Level Cascaded H-Bridge Inverter

In this work, a novel multi-objective voltage-vector-based finite control set model predictive control for a permanent magnet synchronous machine drive fed by a three-phase five-level cascaded H-bridge multilevel inverter is proposed. This algorithm aims to overcome the main issues relative to model predictive control implementation detected in the scientific literature for electric drives fed by cascaded H-bridge multilevel inverters. In detail, the goals are the minimization of computational cost by reducing the number of required predictions, the minimization of the switching devices state transitions, i.e. the switching losses minimization, and the common mode voltage reduction. These goals are fulfilled through an offline optimization process, thus, no additional terms and weighting factors to be tuned are required for the cost function. Experimental validations are presented to prove the effectiveness of the proposed approach. In detail, an accurate electric drive performance comparison, both in steady state and dynamic working conditions, is carried out when the proposed voltage-vector-based model predictive control and the cell-by-cell-based model predictive control are adopted. As comparison tools, current and voltage total harmonic distortion, apparent switching frequency, common mode voltage amplitude, and torque ripple are adopted

Impact Evaluation of Innovative Selective Harmonic Mitigation Algorithm for Cascaded H-Bridge Inverter on IPMSM Drive Application

This paper presents a detailed analysis of the use of a novel Harmonic Mitigation algorithm for Cascaded H-Bridge Multilevel Inverter in electrical drives for the transportation field. For this purpose, an enhanced mathematical model of Interior Permanent Magnet Synchronous Motor (IPMSM), that takes into account simultaneously saturation, cross-coupling, spatial harmonics, and iron loss effects, has been used. In detail, this model allows estimating accurately the efficiency and the torque ripple of the IPMSM, crucial parameters for transportation applications. Moreover, two traditional pulse width modulation strategies, Sinusoidal Phase-Shifted and Switching Frequency Optimal Phase-Shifted have been considered for comparison purposes with an optimized harmonic mitigation algorithm. Thus, this work provides a deep analysis of IPMSM drive performance fed by CHBMI, paying attention to various aspects such as the IPMSM efficiency, torque ripple, current, and voltage total harmonic distortion (THD). Finally, experimental investigations have been carried out to validate the analysis conducted

Optimized Finite Control Set Model Predictive Control for a Three-Phase Five-Level Cascaded H-Bridge Multilevel Inverter fed Interior Permanent Magnet Synchronous Machine With On-Line Candidate Switching State Selection

Model predictive control is a novel control strategy that is attracting the scientific community due to the several advantages it offers, such as the ability to consider system nonlinearities, the possibility to synthesize a control for a MIMO system instead of multiple SISO, and so on. Control feasibility, due to the very high computational cost required to solve the optimal control problem, is a challenge. By considering electric drives fed by multilevel inverters, the control design is more challenging due to the increased number of available output voltage vectors. In this work, a simple algorithm for the voltage candidate reduction is presented: it allows for reducing the control computational cost, minimizing the switching losses, and minimizing dv/dt on phase voltage waveforms

A Hybrid Storage Systems for All Electric Aircraft

A hybrid energy storage system specifically designed for a fully electric aircraft is presented in the paper. The analysis of the time evolution of the power demand of the electric propulsion system during a test mission of Maxwell X-57, an all-electric aircraft developed by NASA, has pointed out the presence of significant peak power during take-off and air tack. Considered the issues related to weight and the volume of the energy storage systems (ESSs) in all-electric aircraft, a hybridization of aircraft ESS with a Supercapacitors (SCs) bank, devoted to smooth peak power demand, has been investigated. A comparison between the simulation results of an electrochemical battery and hybrid ESSs, designed on the test mission of Maxwell X-57 power demand, has been developed. The advantage of hybrid configuration with respect to battery-based one in term of volume and weight reduction is finally presented

A simple DC-Link Voltage Balancing Strategy for NPC Three-level Inverters

Three-level neutral point clamped PWM inverters overcome some limitations of two-level inverters in medium voltage applications, leading to lower device ratings and greater efficiency. However, they are burdened by an intrinsic drawback of the neutral point clamped structure, which causes, under some operating conditions, a voltage imbalance of the DC link capacitors. In this paper, such an issue is faced on a system driven by a dual-carrier PWM strategy through a simple hysteretic control. The proposed technique features a very low computational burden and does not need additional power circuits or sensors. It is first presented theoretically, then its performance is evaluated through simulations

Dead-time impact on the harmonic distortion and conversion efficiency in a three-phase five-level Cascaded H-Bridge inverter: mathematical formulation and experimental analysis

To avoid leg short-circuit in inverters, dead time must be introduced on leg gate signals. Dead time affects the inverter output voltage fundamental harmonic amplitude, voltage harmonic distortion and inverter efficiency by introducing additional voltage drops. In this regard, dead time effects have been widely investigated for traditional two-level three-phase voltage source inverters in the literature but not extensively for multilevel topology structures. This paper provides a detailed analysis of dead time impact on the harmonic distortion and efficiency of Cascaded H-Bridges Multilevel Inverters (CHBMIs). For this purpose, a general mathematical formulation to determine voltage drop due to dead time effects, also taking into account the adopted Multicarrier PWM strategy, has been provided and experimentally validated for a five-level three-phase CHBMI structure. As a comparison tool between expected and ideal inverter output voltage, the percentage voltage error e% is introduced. In most of the cases, e% is lower than 5%, and it starts increasing for very low amplitude modulation index or for specific working points where nonlinearities occur. Furthermore, several experimental investigations have been carried out to evaluate the CHBMI performance in terms of harmonic distortion and efficiency by changing, the values of dead time, modulation index and switching frequency for ten different multi-carried PWM strategies. Experimental results confirm the strong dependency between the dead time impact on the converter performance and the adopted Multi Carrier-PWM (MC-PWM) strategy: as a way of example, converter efficiency can be reduced from 80% to 60% when dead time is increased from 0.5 μs to 1.5 μs and Phase Shifted-PWM (PS-PWM) is adopted