| Title |
Topology and Control Scheme of a Five-Level Asymmetrical Hybrid Flying Capacitor Inverter |
| Authors |
Si-Hyeong Hong ; Dinh Du To ; Sang-Baek Kim ; Dong-Choon Lee |
| DOI |
https://doi.org/10.6113/TKPE.2026.31.4.325 |
| ISSN |
1229-2214(pISSN), 2288-6281(eISSN) |
| Keywords |
Multi-level inverter; Pulse-width modulation; Zero-sequence voltage; Capacitor voltage control |
| Abstract |
This study proposes a five-level asymmetrical hybrid flying capacitor (AHFC) inverter topology derived from the conventional five-level hybrid flying capacitor (HFC) by eliminating the bottom-clamping half-bridge converter. This configuration achieves a 15% reduction in the cost of main components compared with the conventional HFC inverter for a 6 kV/1 MW system. A tailored modified level-shifted PWM strategy is developed to regulate the DC-link and FC voltages without requiring auxiliary balancing circuits. For the 6 kV/1 MW system, the proposed AHFC inverter operating with the developed PWM method exhibits lower total harmonic distortion at medium-to-high modulation indices and reduced power losses compared with the conventional HFC inverter. The effectiveness of the proposed PWM scheme and capacitor voltage balancing control has been validated through experimental results for a 320 V/2 kW hardware prototype. |