Aiming at the special structure of multi-inverter parallel connection in distributed power generation systems
this paper analyzes the mechanism of zero-sequence circulation
establishes the corresponding equivalent electrical model
and proposes a zero-sequence circulation suppression strategy which combines neural network PI control and quasi-proportional-resonant control. Firstly
the traditional PI controller parameter design method is improved
and the neural network is introduced to calculate the PI controller parameters
so as to solve the nonlinear problem of inverter output and complete the zero-sequence circulation suppression in the fundamental wave domain. Secondly
a quasi-proportional resonance controller is designed for the zero-sequence circulation in the third harmonic domain
and the zero-sequence circulation component is controlled by neural network PI control and quasi-PR control to obtain control instructions
and SVPWM zero-sequence duty ratio modulation is carried out
so as to accurately suppress the third-harmonic circulation; Finally
the large-scale simulation software Matlab/Simulink is used for modeling analysis and testing by experimental means. The results show that the proposed control strategy is reasonable and feasible
which can effectively suppress zero-sequence circulation
and has important guidance value for large-scale distributed power generation engineering and application.
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School of Mechanical Engineering, Shenyang University of Technology
School of Electrical and Power Engineering, Taiyuan University of Technology, Key Laboratory of Clean Intelligent Control of Coal Power, Ministry of Education
Beijing Kedong Electric Power Control System Co., Ltd.
Northwest Branch of State Grid Corporation of China
School of Electrical Engineering, Xi’an Jiaotong University