Modeling and Stability Analysis of DC Microgrid for Coal Bed Methane Extraction
Wang Hao1, Wang Cong1, Ma Yong1, Bai Lijun2, Cheng Hong1
1. School of Mechanical Electronic & Information EngineeringChina University of Mining & Technology (Beijing) Beijing 100083 China; 2. Shanxi Lanyan Coal-bed Methane Group Co. Ltd Jincheng 048200 China
Abstract:According to the status of power consumption in the field of coal bed methane (CBM) extraction, a novel power supply system of DC microgrid for CBM extraction was set up, and its stability issues and control strategy were also studied. The DC microgrid for CBM extraction has three-level configuration. The first is the power supply level consisting of PV arrays and battery banks. The second is the power transmission and distribution level comprised of bidirectional Buck/Boost converter. The third is the load level including CBM-well pumping units. The output impedance Zo(s) of the first and second levels was established, as well as the input impedance Zin(s) in series with the controlled source of the third level. Thereafter, a global small-signal model was derived. Since the system instability will be induced by the dynamical and cyclical load of CBM-well pumping units with negative impedance characteristics, a stability control strategy based on virtual impedance was analyzed and discussed in the second level. Simultaneously, droop control was employed to achieve dynamic load power sharing. The impedance criteria were selected to evaluate the overall system stability with and without this stability control strategy by solving the dominant poles of polynomial 1/(1+Zo(s)/Zin(s)). Finally, the DC microgrid model comprised of PV arrays, battery banks and CBM-well pumping units was established in Matlab/Simulink, which verified this method.
王浩, 王聪, 马勇, 白利军, 程红. 煤层气抽采直流微网建模与稳定性分析[J]. 电工技术学报, 2017, 32(14): 194-204.
Wang Hao, Wang Cong, Ma Yong, Bai Lijun, Cheng Hong. Modeling and Stability Analysis of DC Microgrid for Coal Bed Methane Extraction. Transactions of China Electrotechnical Society, 2017, 32(14): 194-204.
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