Small Signal Modeling, Analysis and Control of A Novel Switched Quasi-Z-Source Boost Inverter for Renewable Energy System

In order to supply power from renewable energy source at a low dc voltage to a grid at a high ac voltage, small signal modeling, analysis and pulse width modulation (PWM) control of a novel switched quasi-Z-source boost inverter is presented in this paper. By adding a hybrid switched-inductor-capacitor structure to the traditional quasi-Z-source inverter (qZSI), the new topology generates high dc-ac voltage gain using a low shoot-through duty ratio and a large modulation index to improve the output voltage. The steady-state analysis and PWM control strategy have been discussed in this paper. Meanwhile, State-space averaging method is used to derive the small signal model. Based on the derived small signal and calculation of open-loop transfer function, the stability of the open-loop control is guaranteed. To achieve better performance, a closed-loop control scheme for the proposed topology is introduced. Simulation results are presented to validate the theoretical analysis and control strategy of the novel inverter.