Voltage and Current Programmed Modes in Control of the Z-Source Converter

The Z-source converter (ZSC) is an alternative power conversion topology that can both buck and boost the input voltage with improved reliability. Dynamic modeling of the ZSC from different perspectives has been studied. Based on these models, the dc-link voltage is controlled using direct measurement or measurement of the capacitor voltage. In this paper, two methods of dc-link voltage control of ZSC are analyzed and compared. Both methods are based on measuring the input voltage and the capacitor voltage to estimate the peak of the dc link voltage. Compensator for both voltage mode (VM) and current programmed mode (CPM) controls were designed based on the state space averaged signal model of the ZSC with inductive loading. In CPM, since the order of the system is reduced by one, it is possible to achieve similar dynamic performance with a simpler compensator. Performance of both control methods of the compensated ZSC are verified by simulation and experimental results for input and load disturbances.