Research On Deadbeat Compensation Of Active Power Filter Based On Repetitive Internal Model

With the progress of the times,power electronic technology-based power electronic devices and various non-linear loads in civil and industrial applications,resulting in serious impact on power quality,but also on the quality of the power grid to put forward higher requirements,how to effectively improve the quality of power,more and more people are becoming a concern.Active Power Filter(APF)realizes the high-precision dynamic compensation of grid harmonics,while taking into account the advantages of reactive power compensation,and has become an important research direction in the field of grid harmonic management.This paper takes shunt-type active power filter as the research object,mainly from the grid harmonic current detection link,compensation current without differential shot prediction control link,inverter modulation link and other aspects of the research work,the main work includes the following aspects.Firstly,the generation of harmonics,hazards,harmonic standards and current main harmonic control measures are briefly described,the active power filter is classified,and its principle and structure are briefly analyzed.The first step is the harmonic detection link,and the harmonic detection algorithm based on the instantaneous reactive power theory is used in the harmonic detection link of the grid,and this paper mainly focuses on the low-pass filter and phase-locked loop which affect the harmonic detection accuracy.The phase-locked loop design mainly considers the phase locking in the case of grid distortion,and designs a phase-locked loop based on a smoothing filter.The second step is the harmonic current tracking control link,in the harmonic current tracking control link using two beats ahead of the prediction of the non-differential beat control method,pointing out that the traditional one beat ahead of the hysteresis problem,proposed a combination of Lagrangian interpolation and repetitive internal mode based on two beats ahead of the prediction method,Lagrangian interpolation is used to predict the current value of the next two beats,repetitive internal mode is used to accumulate the error,and error correction,the combination of the two methods The combination of the two methods can solve the disadvantage of poor tracking effect of repetitive internal mode when the load changes suddenly.The third step is the inverter modulation output compensation current process,in the output inverter selected a simple structure,good modulation effect of single-weight H-bridge inverter,modulation method using SVPWM modulation technology,and on the basis of the traditional seven-segment modulation method proposed a simplified five-segment modulation method,each compensation cycle to reduce the switch twice action,can effectively improve the life of switching power devices.Finally,it is verified on MATLAB/Simulink and experimental platform respectively.First,the unit circuits of harmonic current detection,repetitive predictive control,and inverter output are modeled in Simulink,and the conventional repetitive predictive control method is simulated and compared with the improved repetitive internal mode predictive control method proposed in this paper under the conditions of steady-state load and sudden load change,respectively,and then the control method proposed in this paper is also experimentally verified on the APF experimental prototype,which verifies the The effectiveness and feasibility of the proposed control method are verified.This paper has 69 pictures,5 tables and 62 references.