Research On Three-phase Three-wire Shunt Active Power Filter System

Along with the fast development of power industry,non-linear power electronic based equipment has increased significantly in the past decades,which leads to serious harmonic and reactive power pollutions.As a great concern,one of the most effective methods is active power filter(APF),which is the major research object of many scholars.At present,the APF has been widely used in Japan,Europe and the United states,and its application is becoming more mature in China.Therefore,the research on the key technologies of APF is of primary importance.In thesis,the key technology of the three-phase three-wire shunt APF is studied and the main contents is summarized as follows:(1)Working principle of three-phase three-wire shunt APF the main circuit structure of the APF is investigated and the mathematical model the static coordinate is derived.Then the mathematical model of the system in the rotating coordinate is deduced,which facilitates the design of the current controller.(2)i_p-i_q harmonic current detection method based on instantaneous reactive power theory.Comparison with the existing harmonic detection methods,the theory of instantaneous reactive power is introduced.Because the accuracy of the phase-locked loop determines the harmonic current detection,a DSOGI-SPLL algorithm with high precision is designed to ensure the detection performance of the harmonic current(3)The advantages and disadvantages of hysteresis control,deadbeat control,PI control,repetitive control and proportional resonant(PR)control are analyzed in this thesis.The deadbeat controller,PR controller and PI+repetitive controller are designed,complete the design of DC side voltage controller.Simulation models of the system are established in MATLAB,and simulation confirmation to three kind of controller is demonstrated.(4)System hardware circuit design and test verifications.An experimental prototype of a three-phase three-wire shunt APF with a capacity of 3k VA is built.DSP28335 is applied as the agent and model based code generation is applied for code SIL test to verify the validity of the control algrithms This method shortens the system development period,and the development efficiency is increased.Simulation and experimental result indicates that the three-phase three-wire shunt APF system designed in this work has better harmonic compensation performance,and the THD of grid current can be attenuated to 5%.