Research On Multi-objective Optimization And Double Hysteresis Control Of Hybrid Filter

Hybrid filter combines the both advantages of passive filters and active filters,it has better filtering performances in the same time can also ensure that the filtering cost is much lower.Because these advantages Hybrid filter has widely used in power systems.In this paper,we will research and improve the passive filter and active filter in the hybrid filter,the improvement method is as follows:The parameters of passive filter could directly affect the filtering performance,for the multi-objective optimization of passive power filter should taking account of the filtering performance,costs and power factor,so that meet the market requirements and also have a good variability.In order to ensure the synthesized performance of the system,the artificial immune algorithm is optimized with multi-objective.Through the improvement of the affinity function,the multi-objective optimization has realized,the cross and variation operation in the genetic algorithm is introduced to ensure the diversity of the population.The optimized algorithm can filter the harmonics better and realize the multi-objective optimization,it has also avoid the phenomenon of "premature convergence" and prove the feasibility of the algorithm after simulation analysis.For active filter,in the control strategy,the hysteresis control method is designed for double hysteresis,optimize the structure in the space vector.The improved double hysteresis control strategy not only eliminates the interphase effects,but also changes the control dead zone from the original hexagon to the more gentle inscribed circle,so that the error current is consistent at the boundary,effectively reducing the error.This method not only preserves the high precision and fast dynamic response speed of hysteresis control method,but also reduces the breaking frequency and vibration amplitude of the switch.Finally,the feasibility is verified by the simulation application of the hybrid filter.The harmonic of the characteristic is obtained by using 6k±1 times harmonic,and the relevant parameters in the filter are obtained by data analysis and numerical calculation.The partial structure of the substation is analyzed and simulated,and the filtering effect is obtained.It is proved that the hybrid filter has both feasibility and practicality.