Hybrid Five-Level Inverter with Modified Quasi-Z-Source

Abstract

 Hybrid Five-Level Inverter with Modified Quasi-Z-Source proposes the combination of a novel modified quasi-Z-source (MqZS) inverter with a single-phase symmetrical hybrid three-level inverter in order to boost the inverter three-level output voltage. The proposed single-phase MqZS hybrid three-level inverter provides a higher boost ability and reduces the number of inductors in the source impedance, compared with both the single-phase three-level neural-point clamped (NPC) qZSI and the single-phase quasi-Z source cascaded multilevel inverter (CMI).

Hybrid Five-Level Inverter with Modified Quasi-Z-Source Additionally, it can be extended to obtain the nine-level output voltage by cascading two three-level PWM switching cells with a separate MqZS and dc source, which herein is called a single-phase MqZS cascaded hybrid five-level inverter (MqZS-CHI). A modified modulation technique based on an alternative phase opposition disposition (APOD) scheme is suggested to effectively control the shoot-through state for boosting the dc-link voltage and balancing the two series capacitor voltages of the MqZS. The performances of both the proposed MqZS-CHI and the modulation techniques are verified through simulation and experimental results.

Keywords

Cascaded inverter, hybrid five-level inverter, modulation technique, quasi-Z-source.