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Machine learning-based optimization of SiC-based DC-AC inverters for high-efficiency applications
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Machine learning-based optimization of SiC-based DC-AC inverters for high-efficiency applications

Philasande Nhlonipho Ngwenya
M.Eng., University of Johannesburg
2025
Handle:
https://hdl.handle.net/10210/520744

Abstract

Silicon Carbide (SiC) power devices are increasingly applied in high-efficiency systems such as electric vehicles, renewable energy converters, industrial drives, and aerospace power systems because of their superior thermal capability and switching performance. In DC-AC inverters, however, achieving optimum performance depends on the careful selection of switching frequency and dead-time. Conventional fixed proportional-integral control strategies use static switching parameters and fail to adapt under varying operating conditions, which can lead to reduced efficiency, increased thermal stress, and shorter device lifespan. This creates a need for intelligent and adaptive optimisation methods that can improve inverter operation in real time. In this study, a 13 kW, 850 V Wolfspeed reference inverter was modelled in MATLAB/Simulink to generate performance data over a switching-frequency range of 20 to 50 kHz and a dead-time range of 200 to 400 ns. A supervised machine learning model based on a neural network was developed to predict inverter efficiency from these operating parameters. The trained model was then integrated with a Genetic Algorithm to dynamically determine the optimum switching frequency and dead-time parameters. The model was further validated against datasheet values obtained from Wolfspeed, Infineon, and Rohm. The baseline simulation produced an efficiency of approximately 98.26% under fixed control settings of 20 kHz and 300 ns. The ML–GA optimisation framework identified operating points that improved efficiency to as high as 99.63%, while also reducing switching losses and maintaining stable power output. These findings show that intelligent optimisation can significantly improve inverter performance beyond that of conventional fixed-parameter control. Improved inverter efficiency also has wider practical benefits, including lower energy losses, reduced cooling requirements, lower carbon emissions, and improved sustainability in high-demand applications such as electric mobility and renewable energy systems. These results confirm that adaptive, data-driven control strategies are well-suited to unlocking the full performance potential of wide bandgap semiconductor devices across a broad range of high-efficiency power electronic applications. Index Terms: Silicon Carbide (SiC), DC-AC inverter, machine learning, genetic algorithm, switching frequency, dead time, power electronics, neural network, MATLAB/Simulink, ...
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