Hybrid energy storage system (HESS) consists of different electrical storage devices with complementary characteristics to satisfy both the energy and power requirements of the load. This study presents an improved fr...
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Hybrid energy storage system (HESS) consists of different electrical storage devices with complementary characteristics to satisfy both the energy and power requirements of the load. This study presents an improved frequency sharing algorithm for battery/ultracapacitor (UC) HESS in the presence of delay. Time delay is inevitable with the digital implementation of control algorithms. Presence of delay deteriorates the transient response of the system by limiting the bandwidth of inner current loops. The DC-link voltage will settle only after settling of the slower loop, i.e. battery loop, hence the presence of delay will make the system response slower in conventional methods. However, the improved algorithm shares battery current loop error during transients with faster UC current loop and hence DC-link voltage settling becomes faster. Furthermore, for safe and efficient operation, an energy management algorithm (EMA) has been designed that ensures nominal UC voltage and other operational constraints as described in the study. To analyse the effect of UC voltage control loop on the operation of the DC-link voltage control loop during transients, UC voltage control loop with different bandwidths have been designed and tested. microcontroller based implementation was done for experimental verification of the improved control algorithm and EMA.
We investigate the dynamics of a pair of coupled non oscillatory Rayleigh-Duffing oscillators (RDOs here after). The RDO serves as a model for a class of nonlinear oscillators including microwave Gunn oscillators [Gui...
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We investigate the dynamics of a pair of coupled non oscillatory Rayleigh-Duffing oscillators (RDOs here after). The RDO serves as a model for a class of nonlinear oscillators including microwave Gunn oscillators [Guin et al Comm. in Nonlinear Sci. Numerical Simulat, 2017]. Here, the coupling between the two oscillators is obtained by superimposing to each one's amplitude a perturbation proportional to the other one. We demonstrate that the coupling induces more equilibrium points and results in extremely complex nonlinear behaviors including multistability (up to six coexisting attractors), multiple Hopf bifurcations, multi-scroll chaos, and coexisting bifurcation trees. These phenomena are studied in detail by utilizing one-parametric bifurcation plots, bi-parametric Lyapunov exponent diagrams, phase space trajectory plots, and basins of attraction as well. Experimental results captured from an Arduino microcontroller-based realization of the coupled RDOs are included to support the observations made through numerical analysis. We would like to point out that the coupling scheme followed in this work may stimulate the research on multiscroll chaos generation based on coupled nonlinear oscillators.
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