Off-the-shelf diodes as high-voltage opening switches

A semiconductor opening switch (SOS) (also known as SOS diode) is a solid-state nanosecond switch of gigawatt power level. Due to its high pulse repetition rate, long lifetime, and maintenance-free capability, the SOS diodes are becoming increasingly attractive for use in solid-state pulsed power generators. However, the lack of SOS diode manufacturers prevents the widespread use of this technology. This work demonstrates the ability of off-the-shelf diodes to operate in the SOS mode. A wide range of off-the-shelf diodes including rectifier, fast recovery, avalanche, and transient-voltage-suppression (TVS) diodes have been tested as high-voltage opening switches. An experimental arrangement based on a saturating pulse transformer (PT) was developed to test off-the-shelf diodes in the SOS mode. The results obtained were compared with the existent top of the range SOS diodes, used as reference. Two versions of the experimental setup with the initially stored energy of 25 mJ and 10 J were used. The following pulse parameters were obtained using off-the-shelf diodes: 1) peak voltage impulse of 3 kV and rise time of 10 ns with a 110 Ω load (for the 25 mJ setup) and 2) peak voltage impulse of 80 kV and rise time of 20 ns with a 1 k Ω load (for the 10 J setup). Based on the parameters obtained, the door is opened for a future use of off-the-shelf diodes as opening switches in a wide range of solid-state-based pulsed power systems. </p

A Saturable Pulse Transformer Based on Nanocrystalline Magnetic Cores for an Adjustable Nanosecond High-Voltage Generator

This article is devoted to saturable pulse transformers (SPTs), combining the functions of a pulse transformer and a magnetic switch. Two nanocrystalline magnetic cores are investigated in the SPT of an inductive energy storage (IES) pulsed power system based on a semiconductor opening switch (SOS). The first magnetic core has a square hysteresis loop (Br/Bsat $>$ 90%), while the second core has a flat hysteresis loop (Br/Bsat $\sim$ 4%). A test bench with an initially stored energy of 10 J is developed. The circuit design is discussed, and the magnetic materials are compared. Based on the features of the hysteresis loops, two nanosecond high-voltage (HV) SOS generators are tested, with the output voltage adjusted by tuning the input voltage and controlling the bias magnetic field. The influence of the optimal core saturation on the operation of the SOS diode is studied. An adjustable output voltage impulse of more than 200 kV amplitude with a 16 ns rise time is demonstrated on a $1 \text {k}\Omega$ resistive load