Impact of the modulation strategy on the dimensioning of three-phase Z-source inverters

In Z-Source Inverters (ZSI), the modulation strategy determines the size of the inductors and capacitors as well as the system losses. In this paper the impact of the modulation method on the design of the passive components is examined in detail with an Interior Permanent Magnet Synchronous Machine as load. Specific features of several modulation methods are presented for steady state operation and guidelines for the design procedure are developed. It will be shown, that a large number of Shoot-Through states does not necessarily lead to small ripples in the passive components. From these considerations, a method for minimizing the required inductance and ZSI losses is established. Simulations and experimental results, including the measurement of the system losses support the analysis.