A Novel Reduced Switches Nine-Level Inverter Applicable in Aircraft Ground Power Unit

Abstract

Ground power unit (GPU) converters are often required to efficiently manage power distribution in various ground-based applications, necessitating designs that balance performance, and cost-effectiveness. In this paper, a novel nine-level output converter using a single voltage source, 8 unidirectional and one bidirectional MOSFET switches, and two capacitors has been presented to utilize in GPUs. A simple modulation algorithm (PWM) has been applied to achieve a THD of 3.1% on the output voltage at 115/200 V and 400 Hz without the need for additional filtering. With a relatively small output filter, the THD is further reduced to less than 1%. The proposed converter utilized a lower number of devices to output a nine-level staircase in comparison to existing converters. Additionally, the proposed converter employs inherent self-voltage balancing for capacitor voltages, thereby simplifying the control algorithm. In this paper, the topology analysis, modulation algorithm, capacitor calculation, loss, efficiency, and performance analysis of the proposed topology have been presented. The proposed circuit has been compared to recently published papers in terms of switch, capacitor, diode, and source numbers. The theoretical and experimental performance of the topology has been verified by simulation on PSIM software and experimental setup.

Keywords

• Nine-level inverter
• self-balancing capacitor
• single voltage source
• double capacitor
• ground power unit