Nanocoating for Variable Frequency Drives under Square Waveform

High-voltage transients from inverters have been a significant factor in the early breakdown of insulation in motors powered by inverters, compromising the safety and reliability of variable frequency drivetrains (VFD). Polyimide (PI) films are widely used in enamel wire insulation. Despite the PI films' characteristics of high heat resistance, corona resistance, and other excellent performance, the growing need for higher voltage on electrified transportation demands new and optimized approaches to tackle the concern of premature insulation failure in inverter-fed motors under square waveform. Here, we provide a systematic study of different types of PI films, enhanced with a surface engineering method of 2D nanocoating on the polymer films for improved endurance life under bipolar repetitive square waveform. With the application of 2D inorganic coating by using a readily scalable spray coating method, the time to breakdown of polymer films under repetitive pulse aging is significantly improved. This study contributes to a better understanding of the frequency component under pulse width modulation (PWM) accelerated aging tests and demonstrates the importance of insulating surface engineering, which will contribute to the development of new insulation for the safe operation of variable speed drive (VSD) electric motors with high payload efficiency.