Design and digital implementation of voltage and current mode control for the quasi-Z-source converters

Two strategies of peak dc-link voltage control of the voltage-fed quasi-Z-source converters (qZSC) are analysed and compared. Different from the currently available literatures, the peak dc-link voltage is estimated by summing the two capacitor voltages of qZSC. The voltage mode and current mode controls are derived based on the fifth-order small-signal model of the quasi-Z-source network with inductive load. Both controllers are digitally implemented using a digital signal processor (DSP)-based direct digital design approach, where the real-time workshop is used for automatic real-time code generation for a TMS320F2808 DSP. Digital compensators are tuned using Bode diagram and discrete frequency response approaches with a graphical MATLAB/single-input single-output tool. The performances of the proposed control strategies are verified by the experimental results during start-up, input voltage and load disturbances.