Topology,Modulation And Parallel Control Of Current Source Type Three-Phase Three-Arm High Frequency Link Matrix Inverter

Inverters and their parallel technology are widely used in the field of micro-grid systems represented by new energy power generation.Power frequency transformers is used for electrical isolationo at traditional inverters,but high-frequency link inverters are more in line with the requirements of modern power systems due to their small size,light weight,high power density,and ease of installation.For solar power generation systems,voltage source type inverters are usually used,but current source type inverters can eliminate the intermediate DC boost link due to their boosting characteristics,increase system power density,and meet system requirements more.Therefore,this thesis takes the current source type three-phase high-frequency link matrix inverter as the research object,and it has important practical significance to study its topology,modulation and parallel control.Firstly,the current source type three-phase three-arm high-frequency link matrix inverter and applicable de-re-coupling square pulse width modulation and de-re-coupling sine pulse width modulation strategies is proposed.In order to suppress the voltage spike in the switching process of the matrix converter and solve the commutation problem of the matrix converter,a square pulse width modulation and sinusoidal pulse width modulation strategy based on the idea of de-re-coupling is proposed,and two and three values logic conversion are given.The logic conversion method is used to analyze the working mode of the circuit.Under the proposed modulation strategy,the overvoltage spikes at both ends of the switching tube can be suppressed,the safe commutation of the matrix converter can be realized,and the circuit can work normally.Secondly,in this paper,the current source type three-phase high-frequency link matrix inverter parallel system is modeled and the system circulating current is mathematically analyzed.Then,the traditional virtual impedance control is studied,the traditional virtual impedance control is improved,and a method based on The SOGI sequenced virtual impedance droop control scheme is proposed.This program simplifies the program structure,effectively reduces the impact of output current noise on the system,and reduces the circulating current of the parallel system,the power is distributed proportionally,and the output voltage quality is improved.Finally,based on the de-re-coupling modulation strategy,the mathematical model of the current source type three-phase high-frequency link matrix inverter is analyzed,and the large-signal and small-signal mathematical models are established,and then the output CL filter parameters of the inverter are determined.And the voltage and current double closed-loop parameters are analyzed and designed.The Matlab/Simulink module is used to simulate and verify the proposed modulation strategy and control scheme.An experimental platform for a current source type three-phase high-frequency link matrix inverter is built,the experimental software and hardware are designed,and the DSP+CPLD control system is adopted,and the feasibility and effectiveness of the proposed method are verified through experiments.