Active Ageing Control of Winding Insulation in High Frequency Electric Drives

The objective of this work is to present a control technique for power converters capable of slowing down the electrical ageing phenomena affecting the winding insulation of high-speed electrical machines. Such machines are profitably used in aeronautical or electric vehicle applications since they allow a drastic reduction of encumbrance and weight. Obviously, these machines require high-frequency supply voltage and hence converters based on wide band gap devices are the most suitable. Notwithstanding, issues related to high-frequency operation of SiC or GaN MOSFETs are continuously arising, such as the increased electrical stress of the winding insulation due to more severe over-voltages at the motor terminals. These downsides represent a major concern for some applications where system reliability is of the utmost importance like in the aeronautical or automotive fields. This paper provides a detailed description of the proposed control technique and shows the relevant advantages through simulation and experimental results.