Existing dual Z-source networks three-level neutral-point-clamped (NPC) inverters integrates advantages of Z-source networks and three-level inverters. But voltage boost ability is limited. In order to get stronger boost ability，this paper presents switch inductance Z-source there level NPC inverters, which suits Photovoltaic power generation better. The paper analysis working theory of the present inverters in detail. Using improved carrier disposition PWM method control the working of the inverters. Last Simulation results demonstrate the theoretical analysis.