Degree of Fault Tolerance as a Comprehensive Parameter for Reliability Evaluation of Fault Tolerant Electric Traction Drives

This paper describes a new approach and methodology of quantitative assessment of the fault tolerance of electric power drive consisting of the multi-phase traction electric motor and multilevel electric inverter. It is suggested to consider such traction drive as a system with several degraded states. As a comprehensive parameter for evaluating of the fault tolerance, it is proposed to use the criterion of degree of the fault tolerance. For the approbation of the proposed method, the authors carried out research and obtained results of its practical application for evaluating the fault tolerance of the power train of an electrical helicopter

Neutron Stars in Palatini R+αR2R+\alpha R^2 and R+αR2+βQR+\alpha R^2+\beta Q Theories

We study solutions of the stellar structure equations for spherically symmetric objects in Palatini $f(R)=R+\alpha R^2$ and $f(R,Q)=R+\alpha R^2+\beta Q$ in the mass-radius region associated to neutron stars. We illustrate the potential impact of the $R^2$ and $Q$ terms by studying a range of viable values of $\alpha$ and $\beta$. Similarly, we use different equations of state (SLy, FPS, HS(DD2) and HS(TMA)) as a simple way to account for the equation of state uncertainty. Our results show that for certain combinations of the $\alpha$ and $\beta$ parameters and equation of state, the effect of modifications of general relativity on the properties of stars is sizeable. Therefore, with increasing accuracy in the determination of the equation of state for neutron stars, astrophysical observations may serve as discriminators of modifications of General Relativity.Comment: 13 pages, 18 figures. References added. Discussion around Fig. 18 extended. Agrees with published versio

Modelling of a Resonant Charging Circuit for a Solid-State Marx Generator

For the pulsed electric field treatment of plant material on an industrial scale, Marx-type pulse modulators are used as a pulse source. The combination of a conventional Marx generator design equipped with solid-state switches with the concept of resonant charging via current-compensated chokes enables the set-up of a Marx generator having only one active semiconductor switch per stage. Thereby, the pulse shape is defined by the passive components of the RLC-pulse circuit. In the course of the design of such a resonant charging circuit, common-mode current components through the current-compensated chokes need to be considered. Moreover, especially for a generator having its ground connection at its centre, induced voltages versus ground need to be addressed. Therefore, an investigation based on circuit simulations has been made. The simulations showed that the common-mode current components decay to zero just after the resonant charging process and cause a voltage transient at the terminal of the power supply, which needs to be floating versus ground. In order to reduce the amplitude of this transient, the effects of adding a damping resistor have been studied. However, adding this resistor may involve an increase in the common-mode current components. Moreover, the common-mode current components of different chokes are influenced by the on-time of the switches. In the paper, based on the simulation results, different operation modes with and without the damping resistor are discussed. Thereby, the on-time of the switches has been varied. Selected simulation results have been verified by means of measurements

Reliability-Oriented Design of Vehicle Electric Propulsion System Based on the Multilevel Hierarchical Reliability Model

This chapter describes a methodology of evaluation of the various sustainability indicators, such as reliability, availability, fault tolerance, and reliability-associated cost of the electric propulsion systems, based on a multilevel hierarchical reliability model (MLHRM) of the life cycles of electric vehicles. Considering that the vehicle propulsion systems are safety-critical systems, to each of their components, the strict requirements on reliability indices are imposed. The practical application of the proposed technique for reliability-oriented development of the icebreaking ship’s electric propulsion system and the results of computation are presented. The opportunities of improvement of reliability and fault tolerance are investigated. The results of the study, allowing creating highly reliable electric vehicles and choosing the most appropriate traction electric drive design, are discussed

Degree of Fault Tolerance as a Comprehensive Parameter for Reliability Evaluation of Fault Tolerant Electric Traction Drives

This paper describes a new approach and methodology of quantitative assessment of the fault tolerance of electric power drive consisting of the multi-phase traction electric motor and multilevel electric inverter. It is suggested to consider such traction drive as a system with several degraded states. As a comprehensive parameter for evaluating of the fault tolerance, it is proposed to use the criterion of degree of the fault tolerance. For the approbation of the proposed method, the authors carried out research and obtained results of its practical application for evaluating the fault tolerance of the power train of an electrical helicopter

Passive Filter Design Algorithm for Transient Stabilization of Automotive Power Systems

The automotive power system is being increasingly expanded by adding high-dynamic power electronics. These components can potentially cause malfunction or failure of safety-relevant low-voltage components. The susceptibility to disturbances is often reduced by usage of oversized passive input electronics. This paper introduces an alternative means of disturbance suppression by the introduction of system integrated adaptive passive filters. A proposed methodology is presented for examining the suitability of potential access points within complex networks. An algorithmic procedure for the parametrization of several switchable bandpass filter stages is explained. The in-vehicle measurement demonstrates the effectiveness of the dimensioned filter being able to reduce disturbances at 70 kHz by more than 75 %.Passive Filter Design Algorithm for Transient Stabilization of Automotive Power SystemsacceptedVersio