A Single-Stage Boost-Derived T-Type Inverter With Self-Balanced Capacitor Voltage

This article proposes a novel single-stage three-level buck–boost inverter based on voltage multiplier cells. The characteristics of the proposed topology are listed as 1) providing buck–boost operation in a single-stage power conversion, 2) reducing the number of components, 3) low component rating, and 4) automatic capacitor voltage balance without requiring any voltage sensors. A space-vector modulation (SVM) technique is introduced to control the proposed inverter and improve the quality of the output voltage waveform. In the SVM scheme, three nearest vectors are used to generate the output voltage vector in any switching period. The upper shoot-through switching state is adopted to provide buck–boost operations. This state is added within the small N-type vectors. The operating states, steady-state analysis, component selections, and comparison analysis are detailed. A 1-kVA laboratory prototype is built to validate the effectiveness of the proposed inverter. The experimental results show that the switch operates under a zero-voltage switching conditions for both turning-
on
and -
off
. Moreover, the capacitor voltage self-balanced characteristic keeps the voltage difference within 3.8% of the average capacitor voltage.