Research On Two-stage Matrix Converter Based On The ?-Z-source

Two-stage matrix converter(TSMC)is a kind of "green environmental" power converter with excellent performance and compact structure.It has great potential in the field of rail transportation,power system and energy.However,TSMC has not been widely applied in industrialization because its maximum voltage transfer ratio is only 0.866,and it is greatly influenced by the input side.Although many scholars have proposed improved modulation strategies and topology structures to improve the voltage transmission ratio of TSMC,these methods still have some problems,such as the voltage transmission ratio is not obvious,and the topology is more complex.This paper introduces the topology structure and working principle of ?-Z source inverter,analyzes its characteristics.The ?-Z source is introduced into the TSMC,and the topology of ?-Z source TSMC is put forward.Using the high pressure capability,compact structure,anti-interference and so on,the problem of low voltage transmission ratio of the traditional TSMC topology is solved by the more economical and effective scheme.In this paper,the working principle of ?-Z source TSMC is analyzed,and the formula of voltage transmission ratio is derived.Based on its working principle,a dual space vector modulation strategy with direct through vector is proposed.The direct vector is inserted at the opening switching time of the inverter level,so the inverter level does not need dead time.The relationship between the coefficient is optimized,the modulation coefficient is improved,and the output waveform is improved.The simulation model is built by MATLAB/Simulink software,and the simulation waveform is obtained,and the theoretical analysis is verified.Finally,the experimental prototype is built on the basis of the theoretical research of ?-Z source TSMC.The hardware circuit and software system of the experimental prototype are introduced in detail.The hardware circuit mainly includes input power,input filter,?-Z source TSMC main circuit,control circuit and drive circuit,and the software system is based on DSP+CPLD controller to realize modulation calculation.The function of law,fault protection and so on.Analysis of the experimental results verify the correctness and feasibility of ?-Z source TSMC topologies and modulation strategies.