Abstract
The operating voltage of power electronics modules is increasing and it results in higher demands on the electrical insulation. Therefore, it is essential to overcome weak points in the insulation system. The weak points were specified by observing the trace of partial discharges (PDs) by a microscope. When the applied voltage is slightly above partial discharge inception voltage, streamer inception occurred at indented rims of the metallization. Silicone gel is used to encapsulate power electronic circuits. Sometimes the degassing is imperfect and voids may form. These voids induce PDs and limit the reliability of the module. As the indented rims may not be degassed and may contain voids, a simplified encapsulation technique is discussed quantitatively and was verified experimentally. The proposed encapsulation technique could reduce the number and amplitude of PDs.
