A. L. Zhmodikov

Dynistors with nanosecond response times

The results of studies of deep-level dynistors (DLDs) in modes of switching high-power nanosecond current pulses at a current rise rate of up to 200 A/ns unique for semiconductor switches are presented. The dependences of the switching energy loss in DLDs on the amplitude of the control current and the shape of triggering voltage pulses are shown. The electrophysical processes developing at the edge surface of a DLD subjected to the application of high-voltage triggering pulses are analyzed.

Reverse switch-on dynistor switches of gigawatt-power microsecond pulses

A high-power (150 kA and 16 kV) small switch based on an assembly of reverse switch-on dynistors (RSDs) connected in series and a coaxial saturable-core choke, which creates conditions for their efficient switching, is described. An essential feature of this switch is a drastic reduction of the duration of the control action, as a result of which minimum dimensions and a low inductance of the saturable-core choke are ensured at a high (25 kA/μs) rise rate of the switched current. Increases in the control-current amplitude and rise rate that are required for maintaining the triggering charge at a constant level are attained thanks to the use of a fast-acting switch based on new semiconductor devices—deep-level dynistors—in the RSD-control circuit.

Semiconductor switches of laser pumping pulses of nanosecond duration

Switches of megawatt nanosecond pulses based on high-voltage (12 kV) assemblies of drift step-recovery diodes (DSRDs) and deep-level dynistors (DLDs) are described. Circuit diagrams allowing their use in laser technology are considered. Results of testing of the diode and dynistor switches in power supply circuits of nitrogen lasers at a frequency of 100 Hz are presented. Their high efficiency in shaping of pumping current pulses with a rise time of 10 ns and amplitudes of 500 A (a DSRD switch) and 900 A (a DLD switch) is shown.

Prospects of using reverse switch-on dynistors in the modes of switching submicrosecond current pulses

The results of studying reverse switch-on dynistors (RSDs) with an operating voltage of 2 kV and a 12-mm diameter of structures that switch high-power current pulses of submicrosecond duration are presented. It is shown that, in this time interval, the switching energy losses in RSDs are much lower than those for thyristors and IGBT transistors having almost the same area of semiconductor structures and a maximum acceptable blocked voltage. The switching time at which the use of RSDs becomes low-efficient is determined (<0.4 μs).

High-power switches based on reversely switched-on dynistors for high-voltage pulse technologies

The results of comparative investigations of commercially produced reversely switched-on dynistors (RSDs) with an operating voltage of 2 kV and 76-mm-diameter structures are presented. The studies were performed in the mode of switching current pulses with an amplitude of 200 kA and a duration of 300 μs. The electric scheme of the power circuit of the generator of high-power high-voltage pulses with a switch on the basis of an assembly of RSDs is considered. RSD switches with an operating current of 250 kA and operating voltages of 12 and 24 kV are described. Some results of using RSD switches in high-voltage pulse technologies are presented.

High-voltage diode-dynistor switches of high-power alternating current pulses

Electric circuits of high-power switches based on assemblies of diodes that are connected in series to reverse switch-on dynistors (RSDs) are considered. They allow RSDs to be efficiently used in the modes of switching high-power weakly decaying current pulses, which were previously impossible because of high energy losses in dynistors during the reverse-current flow. The results of a comparative study of high-voltage (24 kV) diode-dynistor switches under the conditions of switching current pulses with an amplitude of 50 kA and a damping decrement of 1.3 are presented. The possibility of increasing the switched power is shown.

Semiconductor formers of high-voltage pulses of nanosecond duration

A small former of high-voltage pulses of nanosecond duration based on new semiconductor devices—deep-level dynistors (DLDs)—is described. The former has been developed on the basis of the Marx voltage-multiplication principle and allows formation of 8-kV voltage pulses across an 8-Ω load at a 2.5-kV input-voltage level. A DLD-based former with an output diode opening switch based on assemblies of drift step-recovery diodes connected in series is described. The results of its being tested are presented. Voltage pulses with an amplitude of 25 kV and a rise time of 1 ns are obtained across a 100-Ω load.

Investigation of high-voltage integral pulse thyristors in single-pulse and pulse-train modes

The results of studying the switching capabilities of recently developed high-voltage integral pulse thyristors (HIPTs) with a working area of 0.45 cm2 and an operating voltage of 3 kV are presented. A silicon chip of a thyristor consists of a large number of microthyristor cells that are enabled strictly synchronously with a control-current pulse, thus providing low switching energy losses and allowing a current of up to 8 kA at a pulse duration of 1.5 μs to be switched within 500 ns in a single-pulse mode. The HIPT switching-off time is several microseconds when, after a power-current pulse terminates, a field-effect transistor with a low (tens of milliohms) channel resistance closes the emitter–base circuit. The low switching energy loss and the short switching-off time made it possible to use HIPTs in the mode of switching current pulses with an amplitude of 500 А at a frequency of 50 kHz.

A high-voltage pulse integrated thyristor

The results of investigations of a small-size integrated thyristor recently developed at the Ioffe Physical Technical Institute of the Russian Academy of Sciences are presented. The operating voltage of the thyristor is 3300 V. The thyristor shows high switching performance in the regime of commutation of short current pulses with a high rise rate. The amplitude of a current pulse with a duration of 600 ns reaches 3.3 kA, while the current density is ∼37 kA/cm2.

A capacitor cell of a capacitive energy storage with a switch based on reverse switch-on dynistors

A capacitor cell of a capacitive energy storage designed for operating with an arc load is described. The cell that stores an energy of 64 kJ is based on a high-voltage (18 kV) capacitor and allows formation of current pulses with an amplitude of up to 60 kA. The discharge circuit of the cell contains a semiconductor switch in the form of an assembly of reverse switch-on dynistors (RSDs) connected in series, a crowbar diode switch, and a replaceable toroidal inductor. An assembly of protecting diodes connected in series to the RSD switch excludes the possibility of a flow of reverse-current pulses through dynistors. All elements of the cell are mounted on the capacitor and occupy a volume of 120 dm3.