{'fraction_non_alphanumeric': 0.024705882352941175, 'fraction_numerical': 0.009411764705882352, 'mean_word_length': 5.350746268656716, '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}}
Coil Arrangement Optimization to Improve Efficiency of Multiple-Relay Wireless Power Transfer System

In this paper, an optimization method for arranging a four-coil wireless power transfer (WPT) system is proposed to improve medium or long-distance power transfer efficiency. The system efficiency model with respect to the coil mutual inductance is established. Then the nonlinear constraints about power and distance are given, and the distance between adjacent coils is investigated with the optimal design. The system efficiency with identical coils and different coils is also compared based on the optimization. Finally, the simulation is carried out to show that the system efficiency can be improved from 56.42% under identical-coil-condition to 67.23% under different-coil conditions, where the distance between adjacent coils is optimized.