Operation modes and characteristics of the Z-source inverter with small inductance

Abstract

The Z-source inverter utilizing a unique LC network and forbidden shoot-through states provides unique features, such as the ability to buck and boost voltage with a single stage simple structure. The analysis and control methods provided in the literature are based on an assumption that the inductor is relatively large and the inductor current is continuous and has small ripple. This assumption becomes invalid when the inductance is small in order to minimize the inductor's size and weight for some applications where volume and weight are crucial. Under this small inductance condition, the inductor current becomes high ripple or even discontinuous. As results, the Z-source inverter exhibits new operation modes that have not been discussed before. This paper analyzes these new operation modes and voltage boost relationship of the Z-source inverter under the low inductance and large current ripple condition.