Research On Improved Control Method Of Controllably Inductive Power Filtering System

Modern power electronic technology has injected infinite vitality into the power system,which has improved the productive efficiency of society and the quality of life of the people.However,due to the nonlinear characteristics of power electronic devices,it also brings varying degrees of influence to the power system.The most important problem is harmonic pollution.In this context,the controllably inductive power filtering system(CIPF),as a new harmonic control method,has received extensive attention.In this paper,the CIPF is taken as the research object,and focuses on the analysis of the filtering principle and characteristics of different detection methods.Moreover,combining the special topology structure of the CIPF,the traditional harmonic detection method is improved,and a new control strategy is proposed.At the same time,the validity of the new control strategy is verified by the experimental platform of the CIPF.Firstly,the CIPF is studied from the perspective of circuit model and mathematical model,and the filtering principles and characteristics of different detection methods are theoretically analyzed.On this basis,the influence of harmonic source parameter fluctuation on the system performance under different detection modes is discussed.The reasons for the deviation of the output current of the system are studied,and the influence of the output current phase and amplitude error on the system compensation effect is elaborated.It provides a valuable reference for the selection of CIPF under different working conditions and the solution to the deviation of the output current of the system,so as to ensure the safe and effective operation of the CIPF.Secondly,the research status of harmonic current detection method is introduced.The harmonic detection principle based on instantaneous reactive power theory is analyzed in detail,and the influence of grid voltage distortion on detection accuracy is quantitatively analyzed.Because of the special topology,the detection point and compensation point are in different locations(the difference between phase and amplitude of detection point and compensation point),while the traditional harmonic current detection method based on instantaneous reactive power uses the phase and amplitude information of the detection point so that it is no longer applicable.Therefore,an improved harmonic detection method is proposed.By using the phase information of detection points and compensation points respectively,the problem of detection points and compensation points in different locations of power induction control filter system is solved.Then,on the basis of establishing the mathematical model of the CIPF,a new control strategy based on the Lyapunov function is proposed.The simulation results show that the new control strategy can effectively inhibit the influence of nonlinear load on the network side current.Compared with the traditional PI control,the new control strategy has better voltage regulation characteristics and superior dynamic performance.Finally,in order to verify the filtering performance of the CIPF and the effectiveness of the improved control method proposed in this paper,an experimental prototype of the power induction control filter system is built.The system structure,hardware design and software design of the prototype are introduced,and experimental debugging is carried out on the corresponding platform.The experimental results verify the correctness and effectiveness of the system's filtering performance and the proposed control strategy.