Peak power bi-directional transfer from high speed flywheel to electrical regulated bus voltage system: a practical proposal for vehicular technology

Szabodos, B.; Schaible, U.

doi:10.1109/60.658201

Cited by 36 publications

(7 citation statements)

References 9 publications

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“…These solutions are explicitly dependent on a radial coordinate so that they are more similar to the example in the abstract than the examples in sections 2 and 3. The solution and one of its Bekenstein extensions are asymptotically flat, and also have well defined junction conditions, contrary to what has been stated by Szabodos (1990) [7]. The Bondi and ADM masses of the solutions are calculated.…”

Section: Introductionmentioning

confidence: 61%

Imploding scalar fields

Roberts

1996

Journal of Mathematical Physics

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Static spherically symmetric uncoupled scalar space-times have no event horizon and a divergent Kretschmann singularity at the origin of the coordinates. The singularity is always present so that non-static solutions have been sought to see if the singularities can develop from an initially singular free space-time. In flat space-time the Klein-Gordon equation ✷ϕ = 0 has the non-static spherically symmetric solution ϕ = σ(v)/r, where σ(v) is a once differentiable function of the null coordinate v. In particular the function σ(v) can be taken to be initially zero and then grow, thus producing a singularity in the scalar field. A similar situation occurs when the scalar field is coupled to gravity via Einstein's equations; the solution also develops a divergent Kretschmann invariant singularity, but it has no overall energy. To overcome this Bekenstein's theorems are applied to give two corresponding conformally coupled solutions. One of these has positive ADM mass and has the properties: i) it develops a Kretschmann invariant singularity, ii)it has no event horizon, iii)it has a well-defined source, iv)it has well-defined junction condition to Minkowski spacetime, v)it is asymptotically flat with positive overall energy. This paper presents this solution and several other non-static scalar solutions. The properties of these solutions which are studied are limited to the following three: i)whether the solution can be joined to Minkowski space-time, ii)whether the solution is asymptotically flat, iii)and if so what the solutions' Bondi and ADM masses are.

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Section: Introductionmentioning

confidence: 61%

Imploding scalar fields

Roberts

1996

Journal of Mathematical Physics

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“…As one of energy storage systems, flywheel energy storage system has many advantages such as high efficiency, long lifetime, low capital costs and no environmental pollution, which is applied in the uninterruptible power supply, rail transportation and wind power generation [7–11]. When the flywheel energy storage system is applied in DC micro‐grid, it could control the voltage and waveform of the power system strictly.…”

Section: Introductionmentioning

confidence: 99%

Sensorless control of PMSM for DC micro‐grid flywheel energy storage based on EKF

Zhang

Jian

2018

J. eng.

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“…Permanent magnet (PM) brushless dc motor (BLDCM) controlled FESS, with the advantages of high density, low maintenance, long lifetime, and good compactness, has become a new trend for energy storage, applied more and more in the uninterruptible power supply, rail transportation, and smart grids [1,2]. As shown in Figure 1, the FESS mainly consists of two self-contained parts, that is, the mechanical part (flywheel motor system) and the electrical part (power drive system).…”

Section: Introductionmentioning

confidence: 99%

Singular Perturbation Theory-Based Qualitative Dynamics Investigation of Flywheel Energy Storage System in Discharge Mode

Zhang

Chang

et al. 2014

Journal of Applied Mathematics

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An investigation on qualitative dynamics in a voltage-current dual-loop controlled flywheel energy storage system (FESS) operating in discharge mode is presented in this paper, providing novel insights into the effect of two-timescale characteristics on the safety and stability of energy transmission of FESS. Based on singular perturbation theory, a two-timescale approach is proposed to separate the FESS into the fast and slow subsystems. Stability analysis of the transient fixed points confirms the effects of systemic parameters on FESS’s dynamics and indicates that the FESS shifts from the spiking state to the quiescent state when the slow variable crosses the bifurcation point of the fast subsystem. Mechanism analysis reveals that the root cause of the qualitative dynamics is the voltage instability of the FESS. Moreover, the feasibility boundaries of key parameters are derived, and application requirements of the proposed approach are also discussed, guiding the extension of the approach to engineering applications and solving the dynamics analysis problem to some extent at a theoretical analysis level. Constant voltage discharge experiment is performed based on the FESS test bench built in Key Laboratory of Smart Grid of Ministry of Education, Tianjin University, which validates the theoretical results.

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Peak power bi-directional transfer from high speed flywheel to electrical regulated bus voltage system: a practical proposal for vehicular technology

Cited by 36 publications

References 9 publications

Imploding scalar fields

Imploding scalar fields

Sensorless control of PMSM for DC micro‐grid flywheel energy storage based on EKF

Singular Perturbation Theory-Based Qualitative Dynamics Investigation of Flywheel Energy Storage System in Discharge Mode

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