DC-link voltage ripple analysis and impedance network design of single-phase Z-source inverter

One major drawback of single-phase Z-source inverter is the introduction of low-frequency DC-link voltage ripple, which does not exist in three-phase Z-source inverter. Therefore, proper sizing of impedance network of single-phase Z-source inverter becomes a serious issue. In this paper, impedance network design rules of single-phase Z-source inverter are proposed in order to limit the low-frequency DC-link voltage ripple in an acceptable range. The design rules are derived under the assumptions that open state could be considered as part of active state and linear approximation of inductor current and capacitor voltage is accurate enough. Finally, the feasibility of this impedance network design rules has been validated both by computer simulations and laboratory experiments.