Research On Two-stage Matrix Converter Based On Trans-quasi Z-source

Two stage matrix converter as a green environmental protection power converter has good input and output performance,low harmonics,bidirectional power flow,without DC energy storage,compact structure,small size and other advantages.However,due to some defects such as maximum voltage transfer ratio of TSMC is0.866 and affected by input side interference,TSMC is still not widely used in the industrialization.Although many scholars have proposed to improve the modulation strategy and topology to improve the voltage transfer ratio of TSMC,but these methods still have some problems,such as the improvement of voltage transfer ratio is not obvious,the topology is more complex and so on.In this paper,the topology and working principle of Trans-quasi Z-source inverter are introduced.Combine Trans-quasi Z-source with TSMC,proposed the topological structure of Trans-quasi Z-source TSMC,by using the characteristics of Trans-quasi Z-source,such as high voltage capability,compact structure and anti-interference,the more economical and effective solution to the problem of low transmission ratio of the traditional TSMC topology is solved.In this paper,the working principle of Trans-quasi Z-source TSMC is analyzed,the voltage transfer ratio formula is derived,and the dual space vector modulation strategy for Trans-quasi Z-source TSMC is proposed according to its working principle,the influence of the dead time of the inverter is eliminated by segmented insert the vector state;analyzed the relationship between the boost factor and the modulation coefficient according to the boost characteristics;aimed at the problem that the large inrush current will damage the circuit device,a soft start strategy is proposed based on the capacitance voltage characteristic of the Trans-Z-source network,it inhibit the starting impulse current effectively.The simulation model is built by MATLAB/Simulink software,and the simulation waveform is obtained,verified the theoretical analysis.Finally,the experimental prototype based on the theoretical study of Trans-quasi Z-source TSMC is built,this paper has introduced in detail about the hardware circuit and software system of the experimental prototype.The hardware circuit mainly contains: input power,input filter,main circuit of Trans-quasi Z-source TSMC,control circuit and drive circuit,etc.The software system is based on DSP+CPLD controller to realize the function of space vector modulation,soft start control andfault protection.The correctness and feasibility of the proposed topology,modulation strategy and soft start strategy are verified on the experimental platform.