Signal Flow Graph Modeling And Control Design Of Z Source Inverter

The newly proposed Z source inverter enjoys its unique advantage over the traditional voltage/current source inverter and has become the popular research filed in power electronics.An accurate and simple model is quite necessary to the research on the Z source steady state or transient characteristics. The commonly used state space averaging modeling method can't meet the requirement and hard to understand.The dc side control of Z source converter is hard to design due to its non-minimum phase feature, for the ac side control of three inverter, a stationary frame to rotary dq frame coordination transformation is performed to the three phase signal to achieve zero steady state error control.This dissertation presents the modeling and control design of three phase z-source inverter, By introducing the signal flow graph modeling method, the large signal, steady state and small signal models are derived. Compared with the traditional state space averaging method, this method greatly reduces the computation need and algebraic reduction and is more visual. A resonant adjustor is introduced to the AC side controller, which can achieve zero error track and fast dynamics in the stationary frame thus avoid the coordination transformation and convenient for digital implementation. The simulation results validate the merits of the proposed modeling and control method.