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 500-kV nanosecond pulse generator based on an off-the-shelf solid-state opening switch

This article investigates the use of off-the-shelf (OTS) diodes as opening switches in a 500-kV nanosecond pulsed power generator. A 40-J test bench based on a saturable pulse transformer and a primary thyratron switch is designed to evaluate the performance of the OTS diodes in comparison with standard semiconductor opening switch (SOS) diodes A distinguishing feature of the proposed circuit is the adjustability of the output pulse energy, which is achieved using flat hysteresis loop magnetic cores and variable reset magnetic field. The study confirms the operation of OTS diodes as an opening switch, although highlighting differences in the reverse current conduction that affect the generated voltage pulse characteristics. Based on the successful operation of the OTS diodes, a 500-kV pulsed power generator using an OTS Solid-State Opening Switch (GO-SSOS) is developed. The GO-SSOS provides output voltages of 100–500 kV across resistive loads from 50 Ω to 1 k Ω , with a pulse width of about 100 ns and a rise time of less than 40 ns. The generator achieves a peak power of 335 MW and demonstrates an overall energy efficiency in the range of 30%–70% depending on the load. Operation at a pulse repetition rate of 60 Hz is presented, showing a good reproducibility of the pulses with an amplitude and duration deviation of about 2% and 10%, respectively. No degradation of the OTS diodes has been observed after the tests (more than 1000 pulses). As an example of the possible applications of the GO-SSOS, corona discharge in the air is performed, also proving the stability of all the systems under conditions of strong electromagnetic interference. </p