Three-Phase To Single-Phase High-Frequency-Link Matrix Power Electronic Transformer And De-Re-Coupling Modulation

Matrix converter can realize important functions such as rectifier,inverter and AC-AC converter.On the basis of matrix converter,introducing the idea of high frequency link,a high frequency transformer is added to connect the pre-stage matrix converter and rear-stage matrix converter,which becomes a single stage power electronic device.The topology can make the input voltage,input current,output voltage and output current present good sinusoidal degree and achieve the unit power factor of the network.Compared with the common power frequency transformer,it has the advantages such as high frequency electrical isolation,light weight,low no-load loss,and the controllable frequency and voltage.Among all the key technologies about the framework of smart grid,micro grid and global energy Internet,power electronic transformer has attracted extensive attention.In this paper,a single-stage three-phase to single-phase voltage source high-frequency matrix power electronic transformer(PET)topology is proposed,which uses voltage source circuit topology to realize voltage conversion between input and output.The idea of decoupling is used to analyze the matrix converter for the proposed topology.Combining this idea with the modulation of matrix power electronic transformer makes it flexibly analyze and the control of the bidirectional switches simple.Secondly,according to the characteristics of voltage-source high frequency link matrix power electronic transformer,this paper proposes two voltage-source modulation strategies.The first strategy combines the space vector pulse width modulation(SVPWM)with the hybrid pulse width modulation(HPWM),and the second strategy combines the space vector pulse width modulation(SVPWM)with the sinusoidal pulse width modulation(SPWM).Based on these two modulation strategies,PET can achieve high frequency AC output,high frequency DC output,low frequency AC wide-range output.In order to research whether or not the proposed topology can be applied to wide range,this paper proposes the optimized modulation to decrease the voltage stress of the switches for the pre-stage of current source PET.And the simulation verifies the proposed strategy.Thirdly,in order to ensure that accurate grid phase can be obtained even when the grid is unbalanced,this paper uses the double frequency phase-lock technology which can eliminate the phase missing and phase disorder,and the formula derivation and simulation verification of this method are carried out.The average model and small signal model of three-phase to single-phase voltage source high-frequency link matrix PET are established based on decoupling idea.Finally,the hardware circuit and software system required by the experiment are designed.DSP is used to generate waves and CPLD is used for logic operation to carry out digital control of the experimental platform.The experimental platform of three-phase to single-phase voltage source high frequency link matrix power electronic transformer is established.Experimental results prove the feasibility and effectiveness of the proposed strategy.