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Capacitor voltage control of PV based quasi-z-source inverter

Abstract:

With use of appropriate power converter renewable energy utilization can be increased many folds. Quasi-z-source inverter shows unconventional boosting with single stage power conversion. In this paper, effect of PV array output voltage variation is mitigated with appropriate closed loop control. Small signal models for the dc and ac sides are developed, and the influence of impedance network passive element size selection on the output control transfer function is investigated. The component size of the quasi-z-source inverter's impedance network is designed to provide an underdamped response. Closed loop control is used to maintain a consistent dc-link voltage by regulating the capacitor voltage. At the dc and ac sides, the shoot-through duty ratio and modulation index are regulated, and the closed loop control's effectiveness is evaluated for a step change in PV array output. The obtained outcomes support the described methodology for PV-based quasi-z-source inverter setup.