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Dechirping Compression Method for Nonlinear Frequency Modulation Waveforms
摘要： This letter proposes a novel dechirp processing method for wideband nonlinear frequency modulation (NLFM) waveform which enables low sampling rate of data. As we know, NLFM waveform can easily realize optimal shape of power spectral density which helps to achieve better pulse compression result with low range sidelobes without signal-to-noise ratio degradation caused by weighting as we usually do for LFM waveforms. In the approach, hamming window is adopted in the generation of the NLFM waveform for better balance on the low range sidelobes and a relative small bandwidth. In dechirp operation, the NLFM radar echoes are mixed with a local reference LFM signal, and thus narrowband signals are resulted and only low sampling rate is needed. The dechirped NLFM signals are then up-sampled and inverse dechirped by software and ?nally matched ?ltering is conducted to complete pulse compression. Both numerically simulated data and real radar data are processed to verify the effectiveness of the proposed method.
关键词： nonlinear frequency modulation (NLFM),sampling rate,pulse compression,Dechirp processing
更新于2025-09-23 15:23:52
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[IEEE 2019 IEEE PES Innovative Smart Grid Technologies Europe (ISGT-Europe) - Bucharest, Romania (2019.9.29-2019.10.2)] 2019 IEEE PES Innovative Smart Grid Technologies Europe (ISGT-Europe) - Experimental Research on the Response Time of Three-Phase Inverter on Grid Coupled to Photovoltaic Panels
摘要： The purpose of this paper is to study the response time of SMA Sunny Tripower 5.5 inverters. Material and method: The photovoltaic polycrystalline photovoltaic panels totaling 5000 W, which directly feeds an STP 500TL-20- 5.5kW Sunny Tripower grid inverter. Experimental research was conducted to test the possibility of using these inverters designed for solar systems coupled with wind turbines. As MPPT (maximum power point traking) inverters used for the above purpose, and delivering voltage to the national grid, they have an operating algorithm that allows them to adapt the impedance so that the group of photovoltaic panels delivers maximum power, indifferent to and the angle of incidence of the solar panels. The maximum voltage at which the panels work is 1000V, which allows the insertion of a large number of panels on the same string (virtually 1000/42 = 24 monocrystalline panels or 1000/37 = 27 polycrystalline panels). The algorithm mentioned above probes the power curve at various impedances, and then positions itself on the impedance at which the calculated power was the maximum. After a while, the process is resumed, since it is possible that the power received by the Sun panels has changed.The same algorithm is also respected by wind turbine inverters, with the observation that the sweep of the power curve and the positioning to the maximum value takes much less. This is necessary because the value of the wind speed is much faster than the sun. In addition, the safety of the turbine requires this, as it could lead to a wind turbulence. In conclusion, SMA Sunnny Tripower inverters are very slow in terms of loading and calculating the optimal operating point.
关键词： sampling rate,inverter,response time,on grid,data,photovoltaic pannel
更新于2025-09-16 10:30:52