The Research On Power Quality Of Civil Power Grid Based On Active Power Filter

In now days,as a result of the existence of a large amount of non-linear load,and the three-phase load change frequently in the civil power grid,the power quality of the civil power grid become more and more serious.Active Power Filter(APF)can solve the power quality problems,such as three-phase unbalance,harmonics,reactive power,and become a research hot spot in power electronics field because of fast response and dynamic characteristics of a good compensation effect.Firstly,this paper introduces and analyzes the main power quality problems in the civil power grid and the basic principles of some of power quality controller.For the power quality problems,such as three-phase unbalance,harmonics,reactive power,in the civil power grid,it decided to adopt the shunt APF as the solution to the power quality problems in the civil power grid.Secondly,this paper analyzes the topology and mathematical model of the shunt APF,as the same time,we choose a mid-point capacitor structure as the topology of shunt APF as the point of compensating unbalance and outputting neutral current.In the aspect of control strategy of APF,this paper analyzes Steinmetz balance compensation principle,some of harmonic current detection methods and current tracing control methods in detail.On the basis of analyzing various theories,this paper sets up the structure block diagram of split-Capacitor shunt APF,and analyzes the results of simulation in detail,the result of simulations indicates that the control strategy in this paper is correct and feasible.All the work of this article is summarized in the last part.Meanwhile it states the further potential of this paper.