A Design Method of Nonlinear Controller for Hybrid Active Filter

Abstract

The invention relates to a nonlinear controller design method of a mixed type active power filter. A current-voltage double closed loop control loop is designed for a mixed type active power filter formed by a passive part of limitation of high harmonic waves and an active part of compensation of low harmonic waves. From the view of stability of a current loop, a nonlinear control strategy based on the Lyapunov function is provided, thereby achieving decoupling control of reactive compensation current and fast tracing of harmonic wave reference current. In order to achieve the goal of improving the anti-interference performance of the system, the optimal gain of the controller is gained, so it is ensured that when parameter perturbation or step change of load requirements occur in the system, the system can still stably operate. The sliding formwork nonlinear control method is adopted on the voltage loop, so capacitor voltage is kept stable, dynamic adjustment during the load sudden change is achieved and anti-interference ability of the system is enhanced. The nonlinear controller based on the Lyapunov function is provided, so the mixed type active power filter has a wider application prospect in middle and high power occasions.

Description

technical field [0001] The invention relates to an active power filter technology, in particular to a design method for a nonlinear controller of a hybrid active filter based on Lyapunov functions. Background technique [0002] With the complexity of power grid system load and the diversification of system harmonic content, traditional harmonic control and reactive power compensation technologies cannot meet the requirements of power quality. Active filters are used to dynamically compensate power grid harmonics in real time. One of the effective ways to solve the problem of harmonic pollution. Compared with passive filtering, active filtering has the advantages of fast response and high controllability, but it is difficult to be widely used in medium and high voltage applications due to the limitation of device capacity and cost. In order to overcome the unsatisfactory control effects of the two alone, the hybrid active filter, which combines the single-tuned passive filte...

AI Technical Summary

Problems solved by technology

The traditional control strategy is based on the instantaneous reactive power theory and synchronous coordinate transformation. By calculating the harmonic components in the load current, the compensation control of the harmonic current is realized. The calculation is accurate, but the algorithm depends on the system mathematical model. When the line parameters are perturbed Or when the load demand changes greatly, the harmonic current tracking is likely to produce large errors, and the control performance cannot be guaranteed, seriously affecting the stable operation of the system

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