Reverse switching dynistor pulsers

A unique type of thyristor, the reverse switching dynistor (RSD), has been studied in specially designed pulsers to evaluate their performance for several high-power applications. The dynistor is an asymmetric thyristor with an alternating p⁺ and n⁺ structure in its anode. The device operates like a transistor during turn-on and generates a uniform plasma distribution enabling fast turn-on. This reduces commutation dissipation and permits high di/dt operation to be achieved. An 80-mm diameter device was evaluated in a pulser using a 0.5 ms full-width at half maximum (FWHM), 10-mΩ pulse-forming network (PFN) with a matched load. Operation was demonstrated at 177 kA and a di/dt of 2.8 kA/μs. These tests were performed using a stack of two RSDs in series with a diode to protect against voltage reversal. The devices were triggered by a common driver. The driver unit must be capable of holding off the PFN voltage and generating a high-voltage reverse pulse for turn-on. A. Saturable reactor is required to isolate the main discharge circuit for a period of 2 μs. This technique can be extended to many devices in series, thus, enabling a high-voltage switch to be built using a single driver. Results with two dynistor pulsers are also discussed