Three-Level Quasi-Switched Boost T-Type Inverter: Analysis, PWM Control, and Verification

In this paper, a three-level quasi-switched boost T-type inverter (3L qSBT(2)I) is proposed. A new pulse-width modulated (PWM) control method is presented to reduce the inductor current ripple of the qSBT(2)I. In the introduced PWM technique, the shoot-through duty cycle is maintained constant to keep the modulation index as high as possible. Then, the only control parameters of the qSBT(2)I are the duty cycles of the two additional switches. By controlling the duty cycles of the two additional switches, the voltage gain of the proposed qSBT(2)I can be improved to a value larger than that of the conventional 3L impedance source inverters. The steady-state analysis, operating principles, and comparisons with the impedance source-based 3L inverters are presented. A 1-kW prototype is constructed to verify the operating principle of the 3L qSBT(2)I. An indirect dc-link voltage regulator and a capacitor voltage-balance controller are applied to the proposed qSBT(2)I. Simulation and experimental results are presented.