Novel Variable Edge Time Solid State Pulse Generator for Improved Dielectric Material Aging

This paper will address the generation of a novel test system for electrical insulation systems and components, such as stator slot insulation materials. The premise is to utilize unipolar and bipolar steep wave front high voltage pulses to simulate inverter drive pulses. The choice of either unipolar or bipolar pulses, as opposed to a single type of pulse, allows the study and modeling of the worst-case situation for the dipoles in the insulation material.The authors’ collaboration led to the development of a pulse generator prototype with unipolar or bipolar output, up to 16 kHz pulse repetition frequency and variable rise / fall time. This system provides pulse voltages that resemble more closely the conditions occurring in inverter driven applications. The pulse generator described is characterized by its flexibility (adjustable edge times), energy efficiency, low output impedance and notable load independence of the set edge times.The aging technique developed for this paper will allow for frequency variation as well as wavefront and trailing edge time adjustments. This was utilized in testing magnet wire materials to withstand the high energy encountered in steep wavefront voltage applications.Initial testing was performed on magnet wire (MW) samples to evaluate the ability of the MW dielectric insulation to withstand the high energy encountered in steep wavefront voltage applications, exploring the effect of material type on PDIV level in the knee region of the square wave.