This study aims to propose a high-performance single-phase cascaded asymmetric multilevel inverter topology tailored for aircraft ground power units. It aims to replace conventional two-level architectures, which suffer from high harmonic content at 400 Hz and require bulky filters, with a compact solution meeting strict aviation power quality standards.
The proposed topology integrates binary-scaled DC modules with a conventional H-bridge to synthesize a high number of voltage levels with minimized active switches. To avoid complex high-frequency PWM, a deterministic low-frequency switching strategy is implemented. The system’s steady-state and dynamic performance under load variations were verified via simulations and validated on a 31-level laboratory prototype.
Experimental results demonstrate stable voltage regulation under both steady-state and dynamic load conditions, maintaining the output RMS voltage within a 108–118V tolerance band at 400 Hz. The system delivers a high-quality 31-level output voltage waveform with very low total harmonic distortion, fully complying with ISO 6858 and MIL-STD-704 standards without requiring bulky filters.
This study introduces a novel application of an asymmetric cascaded multilevel inverter optimized for 400 Hz aircraft ground operations. The topology achieves significantly higher voltage level density compared with existing structures while eliminating flying capacitors or clamping diodes, thereby reducing hardware complexity, enhancing overall system reliability and providing rigorously validated power quality performance.
