Research On Harmonic Detection And H_? Control Methods Of Single-phase Active Filter

The rapid development of power electronics technology has brought a lot of convenience to people's production and life.Meanwhile,the widespread use of power electronic devices has brought a large number of harmonics to the grid,causing"grid pollution",which in turn threaten the normal operation of the devices and increase the probability of dangerous accidents.Therefore,the management of harmonics is particularly important.In recent years,active power filters are widely used and applied due to their significant effect on harmonic control.At present,single-phase equipments account for a much larger proportion of power electronic equipment and daily life than three-phase equipments.Consequently,research on single-phase active filters have practical significance.In order to improve the compensation performance and robustness of single-phase active filters,both of harmonic detection method and current tracking control method are designed and analyzed in this paper.The main contents of this paper are as follows:?1?The i_p-i_q detection method based on instantaneous reactive power theory,BP neural network detection method and active separation detection method are analyzed and designed in this paper,and simulation models of these three methods are built,the simulation analysis and comparison are carried out to compare their real-time and detection accuracy,and the difficulty of the implementation of each method and the applicable occasion are considered comprehensively.Finally,their application are obtained in this paper.?2?In order to improve the compensation performance and robustness of single-phase active filter,on the base of the transfer function model of single-phase APF system,an H_?control method based on hybrid sensitivity analysis is proposed based on the transfer function model of single-phase APF system.In order to meet the requirements of the control target,the H_?performance constraints of the sensitivity function and the weighting function are derived.The hybrid sensitivity problem of the single-phase APF system is transformed into the standard H_?control problem.Finally,the appropriate weighting function is selected,and two controllers are obtained.In order to verify the effectiveness of the controller,the relevant simulation model is built for simulation analysis.The simulation results show that the H_?controller can ensure that the fundamental component is not affected and can effectively filter out 3^rd,5^th,7^th and 9^thh harmonics under the steady state;When the load fluctuates,the two controllers can maintain good compensation performance and have favorable robustness.?3?In order to avoid the selection of weighting function and the high order controller,on the base of the switching function model of single-phase APF,an H_?control method based on linear matrix inequality is proposed.Through the establishment of the standard H_?control model of the single-phase APF system,the problem of solving the H_?output feedback controller of the single-phase APF system is transformed into a linear matrix inequality.Finally,the parameter values of the controller are obtained through the LMI toolbox.The simulation results show that the designed controller has good compensation performance and anti-interference ability,what's more,the compensation effect is better than the previous method.