New Modulation Strategy for Volume Reduction of Inductor for q-Z-source Inverter

This paper proposes a new modulation method based on Space-Vector Modulation for Z-source inverter, which can minimize the inductor volume of its impedance source by changing arrangement and distribution of the shoot-through state. The proposed method can reduce the inductor current ripple by 58.3% compared with the conventional method which has six equal shoot-through intervals. When achieve the same inductor current ripple, the proposed method can reduce the inductor volume. Due to the number of switching in one control cycle in proposed method is increased by 33.3%, inductor current ripples with same switching frequency were also compared. The current ripple of the proposed method can still be reduced by 44.5% compared with the conventional method. The inductor ripple reduction and inductor volume reduction of the proposed method were confirmed in experiments with a 3-kW-class qZSI prototype. Its results are consistent with the theoretical calculation results, and it was confirmed that the proposed method does not increase the total loss for the same switching frequency.