The Study Of Detection And Control Methods In Single-unity Power Quality Conditioner

As the main energy of the modern society, electrical power is applied in all aspects of life, and electrical power quality is related with national economy. Unified Power Quality Controller (UPQC) is one of the development trends of Custom Power, which combines the functions of voltage compensator, current compensator and energy storage. Multiple power quality regulation functions are implemented in UPQC simultaneously. It must have a prospective future.At first, the topology and the function of UPQC are explained in the paper. Then the detection method and the control strategy, which are the important parts affecting the compensation effect of the UPQC, are discussed and investigated in detail in the papers. For the control strategy, through the study of active power filter, this paper summarizes the active power filter control strategy of direct compensation, points out the advantages and disadvantages of each, and selects the timer-control hysteretic pulse wide modulation control method for the control method UPQC.Quickly and accurately detecting the harmonic signal from the target is the key to achieve the goal of compensation. In the basis of the APF detecting method, this paper summarizes the harmonics detecting methods based on the instantaneous reactive power, and an improved harmonic detection algorithm in single-phase circuit based on the instantaneous reactive is proposed, in which a time-delay circuit is used to reducing the delay-time of the lower-pass filter. The influence of the third harmonic would be clear by the time-delay circuit, so the total delay-time of the improver method is shorter. Theoretical analysis and simulation experiment prove that the proposed harmonic current detection algorithm is correct and effective.In the basis of the above, this paper makes reference to the literature of single-unity power quality conditioner of the model, analys the course of its work, and builds a simulation model at Matlab/Simulink. Through a variety of issues of power quality compensation simulation to verify the feasibility of the algorithm.