{'fraction_non_alphanumeric': 0.02993348115299335, 'fraction_numerical': 0.0022172949002217295, 'mean_word_length': 4.901960784313726, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Research on DC Grid Power Characteristics and DC Active Power Filtering

When nonlinear load is powered by DC grid, harmonic currents and distortion power are produced. At first, the concept of the DC active power filter (DC-APF) is presented in this paper after the analysis of instantaneous power and power factor in the DC network. The DC-APF includes the parallel type, the series type and the series-parallel type, etc. The circuit topologies and the working principles of two kinds of DC-APF are proposed and analyzed: (1) the general type, which can compensate harmonic currents and reactive currents; (2) the correction type, which can track the DC voltage. The comprehensive simulation analysis of the double-bridge half-controlled DC-APF by means of MATLAB/SIMULINK and the experiment of the correction type prove the validity and the feasibility of these topologies and operating principles.