Single-Phase Current Source High-Frequency Link Matrix Power Electronic Transformer And De-Re-Coupling Modulation

High frequency link matrix power electronic transformer is composed of high frequency transformer and matrix converter.This system can achive the unit power factor on the grid side,so that the input and output voltage and current have a more ideal sinusoidal wave.It has the advantages of high frequency electrical isolation,small size,light weight,small no-load loss,no need for insulating oil,and controllable frequency and voltage.This topology also has important research significance in the field of power electronic devices,and can be widely used in wind power generation,smart grids,electric vehicles and vehicle power supplies.In this paper,a new topology is proposed,and a suitable modulation strategy is proposed for the converter problem of power electronic transformer.In this paper,high frequency link matrix power electronic transformer as a research direction,a single-phase current source AC/AC high-frequency link matrix power electronic transformer topology is proposed.The current source circuit topology is used to achive the input-output voltage conversion.The pre-stage uses the LC filter and matrix converter structure,the rear-stage uses the matrix converter and CL filter structure,and the high frequency transformer is used for magnetic coupling and power transfer in the middle to achieve AC-HFAC-LFAC(HF: High Frequency;LF: Low Frequency).Based on the proposed topology,a current source de-recoupling modulation strategy combining a pre-stage unipolar frequency doubling SPWM(Sinusoidal Pulse Width Modulation)and a post-stage HPWM(Hybrid Pulse Width Modulation)is proposed.Which can make the pre-stage and post-stage bidirectional switch of the matrix converter work collaboratively and can effectively avoid the voltage spike generated when the switching tube is commutated due to the leakage inductance of the high-frequency transformer.The modulation principle diagram and the driving logic diagram are given,under which the pre-stage bidirectional switch tube is integrally driven and the post-stage bidirectional switch tube is discretely driven.Vertical drive and detailed analysis of its working mode.In order to broaden the conversion characteristics of the PET,a simulationplatform is built based on MATLAB/Simulink simulation software.Based on the analysis of the modulation principle and the working state of the main circuit,the modulation strategy was carried out with different load capacities,voltage transformation,frequency conversions and cascade mode is verified.The effectiveness and feasibility of the proposed topology and modulation strategy are verified by simulation.In this paper,a simple closed-loop control of a single-phase current source AC/AC high-frequency link matrix power electronic transformer is given,and the design methods of input LC filter and output CL filter are given.Analysis of single-phase phase-locked loop based on virtual two-phase of second-order generalized integrator.The double closed loop control system of voltage outer-loop and current inner-loop is established,which based on PI control.The parameter design method of PI regulator was analyzed in detail,and simulation was performed to verify the feasibility of the closed-loop control system.Based on theoretical analysis,the hardware circuit is designed,and a digital control circuit combining DSP and CPLD is used to build an experimental platform for single-phase current source AC/AC high-frequency link matrix power electronic transformers.Experimental verification with different loads is performed.The experimental results prove that the proposed topology and modulation strategy have good load carrying capacity.