Equivalent impedance model analysis of modular multilevel matrix converter
The impedance modeling of modular multilevel matrix converter(M3C)is the key theoretical basis for stability and fault characteristic analysis of flexible low-frequency transmission system.The topology,mathematical model and control strategy of M3C are introduced.On this basis,considering the topology structure characteristic of M3C,dq coordinate transformation process and the double dq decoupling control,the response characteristic of disturbance current-bridge arm voltage-disturbance voltage transfer is analy-zed.The relationship between the M3C equivalent impedance characteristic and frequency is derived,and the M3C equivalent impedance mathematical model is established.The accuracy of the theoretical analysis of the equivalent impedance is verified by using the frequency sweeping method on the PSCAD/EMTDC simulation platform,and the effects of different factors such as control parameters,operation power and pri-mary parameters on the impedance-frequency characteristic of M3C are discussed.