Reserch On Interference Suppression Strategy Of PWM Rectifier

The traditional technology of uncontrolled rectifier and phase-controlled rectifier has low power factor,which has caused large harmonic pollution to the power grid,and can not meet the requirements of modern society for power electronic equipment.The PWM rectifier replaces the uncontrolled and semi-controlled switching transistors with the full-controlled devices represented by IGBT,which overcomes the shortcomings of uncontrolled rectification and phase-controlled rectification,and has the advantages of high sinusoidal input current and four-quadrant operation,and is widely used in power electronic power conversion field.In this paper,the three-phase voltage source PWM rectifier is taken as the research object.Firstly,the development and basic working principle of the three-phase voltage source PWM rectifier are briefly introduced,then the mathematical model of the rectifier in abc,αβ and dq coordinate system is constructed and the voltage loop,Current loop and space vector PWM algorithm is studied.On the basis of this theory,a three-phase voltage-source PWM rectifier system based on by traditional double PI voltage outer loop and current inner loop is built.After that,the anti-interference ability of the traditional double pi control is improved,and a new dual pi control structure is proposed,and the simulation research is carried out.Finally,the TMS320F28335 DSP chip is used as the control core to achieve the purpose of voltage and current double PI control.The main contents of this paper are as follows:1.In terms of theoretical analysis,this paper mainly introduces the topological structure of three-phase voltage type PWM rectifier and the construction of its mathematical model in the coordinate systems of abc,αβ and dq.2.In terms of system modeling and simulation analysis,the traditional dual-pi control system of external voltage loop and internal current loop and the improved dual-pi control system were respectively constructed in the Matlab/Simulink environment, and the simulation waveforms of main performance parameters of the two systems were compared under the condition of different external interference.3.In terms of design and construction of the prototype,design is made respectively from the aspects of inductance and capacitance,voltage lifting circuit,DAC circuit, driving circuit and sampling circuit of the main circuit of the rectifier.In the end,a three-phase voltage PWM rectifier prototype is formed through cascade.Through the debugging of the prototype,the waveform of main performance parameters of the system was collected under different interference.Through comparative study,it was concluded that compared with the traditional double-pi control,the double-picontrol proposed in this paper has the advantages of high sinusoidal amplitude of ac current and small fluctuation of DC side voltage.