Small signal modeling, analysis and control of Г-Z-Source Inverter

In this paper, small signal modeling, analysis and closed-loop control of Γ-Z-Source Inverter (Γ-ZSI) as a member of the magnetically coupled impedance-source converters family are investigated. The Γ-ZSI is modeled using the state-space averaging method. By applying perturbations to state variables, system control and disturbance inputs, the small signal model is obtained. Using the derived small signal model and calculation of open loop transfer functions, the closed loop control strategy is designed for DC side (shoot-through duty cycle control) as well as the AC side (inverter output voltage control). The small signal model of the converter is validated through comparison of the dynamic responses analysis of the derived model and detailed electrical model simulations. Besides, closed loop simulation results are presented to evaluate the effectiveness of the control strategy. Finally, frequency response analysis is carried out to verify the dynamic performance characteristics and design limitations of the Γ-ZSI. All provided simulation results and analysis approves the proposed model accuracy and control system performance.