Mathematical Model and Analysis of the Z-Source Inverter

Model and analysis of Z-source Inverter is the dominant aspect to investigate the performance of the Z-Source Inverter. This paper presents a comprehensive analysis of the Z-Source Inverter model by the aid of mathematical analytical approach. AC small-signal perturbations are derived based on the state-space averaging model and state variables are linearizations at equilibrium (steady-state values). The AC small-signal model is analyzed to study the changes that occur in the behaviour of ZSI such as change the input voltage, the current that passes through the load, or the shoot-through duty cycle. Moreover, the mathematical model gives the ability of choosing the optimal values of the capacitance and inductance of the Z-source network. The analytical results are verified by comparing them with those of the actual ZSI switching circuit analysis method. The comparison shows significant convergence between the presented analytical method and the actual ZSI analysis method. The percentage errors between the two methods, for both of the state variables (inductance current and capacitance-voltage) in the ZSI, are very acceptable for major analysis requirements. The presented model can replace the actual ZSI switching circuit model in an efficient manner in terms of the accuracy of the results.