New Modulation for Z-Source Inverters With Optimized Arrangement of Shoot-Through State for Inductor Volume Reduction

In this article, a new modulation method based on space-vector modulation for Z-source inverters is proposed. One modulation method named ZSVM6 is attractive for the use of SiC-
mosfet
s since it can avoid the body-diode conduction. The proposed modulation is based on ZSVM6 and can reduce the current ripple in the inductor in its impedance source by introducing additional shoot-through intervals to divide the longest active state. The proposed modulation can reduce the current ripple by 44.5% in comparison with that by the conventional ZSVM6 under the same switching frequency. Conversely, the inductance required to achieve the same current ripple can be reduced by the same ratio. The reduction of the inductor volume through the proposed modulation was confirmed experimentally using a prototype of quasi-Z-source inverter and fabricated inductors. The experimental results also confirmed that the inductor size reduction can be achieved without increase in the total power loss of the converter. A harmonics analysis based on the experiments showed that the harmonic components in the current can be increased through the proposed modulation. However, the frequency range of the increased components can be much higher than the control frequency; therefore, its influence on the design of passive components is not severe.