An improved modulation strategy for the three-phase Z-source inverters (ZSIs)

Z-source inverters (ZSIs), compared to the two-stage architecture, i.e. boost-converter (BC)-fed voltage source inverter (VSI), embrace some interesting features, like the reduced size and complexity of the entire conversion system. Several research activities have been established to improve the performance of the so-called ZSI since it has been proposed in 2003, and many modifications
have been introduced accordingly. These modifications include the structure of the ZSI, i.e. modifying the topology itself, and its modulation. From the modulation prospective, all the modulation strategies of the ZSI utilize two shoot-through (ST) pulses per switching cycle, resulting in an increased number of commutations, i.e. the switching frequency is increased. However, this
increased switching frequency is affecting only the input filter, i.e. the input impedance requirements, but not the output filter, as the added ST pulses are inserted inside the zero states. Hence, in this digest, an improved modulation strategy is proposed to enhance the performance of the three-phase ZSIs, including all the other improved topologies. The proposed modulation strategy,
which is called high-boost-based modified space vector modulation (HB-MSVM), utilizes one ST pulse per switching cycle and effectively reduces the number of commutations of the switches compared to the VSI, where one switch is continuously conducting for one-third the fundamental period.