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In order to study the unique dynamic behavior of the lithium-ion battery system in the periodic high-rate pulse discharge, a frequency-domain impedance model and a dynamic extraction method of impedance parameters are proposed. Moreover, a 24-kWh lithium battery system is built to carry out the pulse-discharged cycle experiment. The harmonic characteristics in high and low frequency pulse discharge are studied by harmonic analysis method. Besides, the impedance characteristics of the 24-kWh lithium battery system under different state-of-charge and different cycles are analyzed quantitatively. The results show some new characteristics and verify that the proposed frequency-domain impedance model and impedance extraction method are well qualified to analyze the frequency-domain characteristics and dynamic behavior of the periodic pulse-discharged lithium battery system. [ABSTRACT FROM AUTHOR]

This paper has introduced two important indexes, turn-off surge voltage (TSV) on power switch and peak positive pole potential (PPPP) of storage batteries, which can be used to evaluate switching transient process of high-voltage energy storage system. Research on them is of great significance to power switch choice and high-voltage isolation design in engineering applications. Power switch response process at the turning off moment and transient process in freewheel stage have been analyzed by the established small-signal model of single power switch; then, a power switch test platform for hybrid energy storage system was built to verify it. Taking pulsed-power supply charging device with a novel inductor of low resistance and high inductance as a research object, this paper has analyzed dynamic process of the TSV and the PPPP at the turning off moment through establishing state space model of the whole system. Comparison shows that the numerical curves match the simulated curves well. Finally, the exactness of the employed model has been further verified in two pulse capacitor charging experiments. [ABSTRACT FROM AUTHOR]

Due to the overlapping structure of the offset quadrature amplitude modulation-based orthogonal frequency-division multiplexing (OQAM-OFDM) signals, the peak-to-average power ratio (PAPR) in OQAM-OFDM systems cannot be efficiently reduced by existing PAPR reduction methods, which independently consider the PAPR reduction in each data block. In this paper, a novel multiblock tone reservation (MB-TR ) scheme is proposed for the PAPR reduction in OQAM-OFDM systems. The key idea of the MB-TR scheme is to exploit the overlapping structure of the OQAM-OFDM signals and jointly consider the adjacent data blocks to obtain the clipping noise. To effectively eliminate the peaks of the OQAM-OFDM signals, the MB-TR scheme generates the peak-canceling signal by employing the weighted least square algorithm to fit the waveform of the peak-canceling signal to the waveform of clipping noise. Simulation results and analysis show that the MB-TR scheme could offer better PAPR reduction with lower computational complexity than the clipping control tone reservation scheme directly employed in OQAM-OFDM systems. [ABSTRACT FROM PUBLISHER]