CAREER: Accelerated Insulation Aging due to Fast, Repetitive Voltage Pulses from Wide Bandgap Power Electronics

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Title: CAREER: Accelerated Insulation Aging due to Fast, Repetitive Voltage Pulses from Wide Bandgap Power Electronics Abstract: By 2030, it is expected that 80% of all electric power will flow through power electronics systems. Wide bandgap power modules that can tolerate higher voltages and currents than silicon-based modules are the most promising solution to reducing the size and weight of power electronics systems. These wide-bandgap power modules constitute powerful building blocks for power electronics systems, and wide bandgap-based converter/power electronics building blocks are envisaged to be widely used in power grids in low- and medium-voltage applications and possibly in high-voltage applications for high-voltage direct current and flexible alternating current transmission systems. One of the merits of wide bandgap devices is that their slew rates and switching frequencies are much higher than silicon-based devices. However, from the insulation side, frequency and slew rate are two of the most critical factors of a voltage pulse, influencing the level of degradation of the insulation systems that are exposed to such voltage pulses. The shorter the rise time, the shorter the lifetime. Furthermore, lifetime dramatically decreases with increasing frequency. Thus, although wide bandgap devices are revolutionizing power electronics, electrical insulating systems are not prepared for such a revolution; without addressing insulation issues, the electronic power revolution will fail due to dramatically increased failure rates of electrification components. This research plan pioneers overcoming the accelerated aging of insulation systems under wide bandgap-based voltage pulses, and its goal is to characterize, model, and mitigate this insulation degradation issue under atmospheric pressure. The integrated education plan will help to train the next generation of high electric field and electrical insulation engineers/ researchers, who are needed to maintain the competitive vitality of the U.S. power electronics and power system workforce regarding the two trends toward (I) high-power-density designs in various applications and (II) the increasing use of power electronics, leading to the accelerated aging issue. The education plan also includes outreach to students in grades K-12 and underrepresented groups.Accelerated aging and degradation of insulation systems in power system components as a consequence of exposure to the high slew rates (ranging from tens to hundreds of kV/μs) and repetitive (frequencies ranging from hundreds of kHz to MHz) voltage pulses that originate from emerging wide bandgap-based power electronics systems are one of the most significant barriers for the acceptance and utilization of wide bandgap power modules. This research endeavor aims to (1) characterize, (2) model, through a “theoretical-based Multiphysics” approach, and (3) mitigate the accelerated aging problem. Through comprehensive experimental investigations, the accelerated aging issue will be characterized, and the experimental data will also be used to validate the Multiphysics models developed. Furthermore, optimal mitigation methods to solve the accelerated aging problem will be determined through the models that will be developed and verified experimentally. Moreover, high-frequency electromagnetic transient models for rotating machines, transformers, cables, and transmission lines will be developed to determine (i) overvoltages, (ii) electrical stress, and (iii) thermal stress on different components including motor and transformer windings, and stress grading systems in electrical motors and cable terminations under wide bandgap-based voltage pluses.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.