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.     

Studying dynistor switches with nanosecond switching times

The results of studying the process of switching deep-level dynistors (DLDs) with 16- and 24-mm-diameter structures in the modes of switching micro- and nanosecond pulses with amplitudes of several kiloamperes are presented. It is shown that the dynistor switching process is highly uniform. The results of DLD tests at a high repetition rate of switched current pulses are presented. The principle of constructing high-power DLD switches with independent triggering of dynistors, which is based on the use of a single-turn saturable-core choke in the power circuit and a saturable-core isolating transformer in the DLD triggering circuits, is described. A DLD switch with an operating voltage of 8 kV is considered, which can switch current pulses at a frequency of 2 kHz with an amplitude of 1.5 kA and a duration of 200 ns.     

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).     

A High-Voltage Reverse Switch-on Dynistor Switch with a Control Circuit Based on Magnetic-Compression Sections

A high-voltage switch of submicrosecond range based on an assembly of reverse switch-on dynistors (RSDs) connected in series and a coaxial saturable-core choke is described. Dynistors are triggered using a control circuit in the form of a high-voltage magnetic-compression section, in which the current-forming capacitor is charged from the power-circuit capacitor using an additional low-power saturable-core choke. The results of tests of a small-sized (200 × 200 × 55 mm) RSD switch with an operating voltage of 6 kV switching 1-kA current pulses with a 600-ns duration are presented. Low switching energy losses in dynistors make it possible to use devices with a 12-mm diameter of the structure in the RSD assembly. Their temperature was within 20°C at a switching frequency of 100 Hz.     

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 Reverse Switch-On Dynistors Upgraded for Reducing the Energy Loss when Switching Reverse-Current Pulses

The results of investigations of new semiconductor devices, reverse switch-on dynistors dynistors–diodes (RSDDs), with an operating voltage of 2 kV and a 50-mm diameter of the structure are presented. Their comparison with conventional RSDs shows that the losses in RSDDs are approximately 2 times lower when high-power reverse-current pulses are switched, the losses are virtually the same during switching, and the losses are 15–20% higher when switching rapidly rising forward-current pulses. The limiting abilities of RSDDs are determined when switching unipolar current pulses with a duration of 300 μs: 30 and 100 kA in the reverse and forward directions, respectively. The possibility of reliable switching of alternating slowly damped current pulses with a duration of 40 μs and amplitudes of the first forward and reverse half-waves of 90 and 65 kA, respectively, with which conventional RSDs cannot operate, is shown.     

Small switches of high-power microsecond pulses on the basis of high-voltage integrated pulse thyristors and reverse switch-on dynistors

A high-voltage switch on the basis of a small unit of series-connected high-voltage integrated pulse thyristors (HVIPTs), which were developed at the Ioffe Physical Technical Institute, was designed and investigated. At a power voltage of 25 kV, current pulses of microsecond duration with an amplitude of 2.8 kA and a rise time of 0.8 μs were switched. The attained current density through an HVIPT (5.6 kA/cm²) appreciably exceeds the permissible current density for conventional thyristors. It is shown that the developed HVIPT unit can be used in the triggering circuit of a high-power assembly of reverse switch-on dynistors (RSDs) at an operating voltage of 25 kV, which consists of 14 series-connected dynistors with a diameter of their structures of 24 mm. The RSD switch with a triggering circuit on the basis of HVIPTs allowed switching of rapidly rising current pulses with an amplitude of 20 kA and a duration of 150 μs. The small dimensions of the HVIPT unit (4 × 10 × 32 cm) and the RSD assembly (7 × 7 × 34 cm) determine the wide prospects for using them in high-power pulse technology.     

A High-Voltage Reverse Switch-on Dynistor Switch with a Transistor Control Circuit

A high-voltage switch based on an assembly of reverse switch-on dynistors (RSDs) connected in series is described. In this device, the dynistors are triggered by the current, which is formed using parallel control transistor circuits and low-power shunting capacitors. The results of tests of a high-voltage (10 kV) RSD switch in the regime of switching high-power (6 kA) and short (1.5 s) current pulses are presented. The switch reliably operated under experimental conditions at a frequency of 300 Hz with very low energy losses in small-sized dynistors with a 24-mm-diameter structure (their heating was under 55°C).     

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.     

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.     

Comparative investigations of submicrosecond switches based on reverse switch-on dynistors and deep-level dynistors

Results of comparative investigations of switches on single reverse switch-on dynistors (RSDs) and deep-level dynistors (DLDs) during switching high-power submicrosecond current pulses in conditions, when the control circuits feature the same power consumption, are given. It is shown that, in this mode, the DLD switches have certain advantages specified by a smaller intrinsic inductance value and more efficient switching during the heating of the dynistors.     

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.     

Switches of High-power Current Pulses with a Submicrosecond Rise Time on the Basis of Series-connected IGBT Transistors

The results of comparative investigations of assemblies of series-connected IGBT transistors (IRGPS60B120KD) with control circuits that are based on pulse transformers and ADuM21N microcircuits, which have a high insulation strength, are presented. The conditions for efficient switching of high-power current pulses with a submicrosecond rise time are determined. A small switch with an operating voltage of 12 kV that consists of two parallel-connected transistor assemblies is described. It provides switching of microsecond current pulses with an amplitude of 500 A and a rise time of 200 ns at a frequency of 100 Hz under natural cooling. The possibility of scaling the results is shown.     

A Switch Based on Reverse Switch-on Dynistors with a Diode Sharpener of Switched Current Pulses

A principle of constructing a combined semiconductor switch based on a diode assembly and an assembly of reverse switch-on dynistors (RSDs) is considered. The diode assembly serves as a sharpener of current pulses switched by the RSD assembly. The results of tests of a combined switch, which forms 3.5-kV voltage pulses with a duration of 1 s and a rise time of 10 ns at a load of 10 , are presented. Ways of enhancing the switching capabilities of RSD switches with diode sharpeners are presented.     

A generator of high-voltage nanosecond pulses with a subnanosecond rise time

A generator of high-voltage pulses of nanosecond duration with a subnanosecond rise time is described. The generator contains a nanosecond-pulse shaper based on an assembly of drift step-recovery diodes (DSRDs) connected in series and a sharpening switch based on an assembly of deep-level dynistors (DLDs) connected in series. The results of tests of this generator at a pulse repetition rate of 100 Hz are presented. Voltage pulses with an amplitude of 20 kV, a rise time of 0.3 ns, and a duration of 10 ns are formed across a load with a resistance of 50 Ω.     

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.     

Investigation of Reversely Switched-on Dynistors in an Unconventional Switching Mode by Submicrosecond Control Current Pulses

Instruments and Experimental Techniques - The results of optimizing a high-power switch that consists of a block of reversely switched-on dynistors with 50-mm diameter structures, a dynistor...     

A Unit of Shock-Ionized Dynistors with a High-Voltage Pulse Sharpener in the Control Circuit

Instruments and Experimental Techniques - The results from studies of a high-voltage unit of shock-ionized dynistors in the switching mode of current pulses with an amplitude of several kiloamperes...     

Formation of High-Power Pulses of Nanosecond Duration by Generators on Reverse Switch-on Dynistors with Sharpening Circuits Based on Diode Opening Switches

The basic principles of constructing generators of nanosecond pulses on reverse switch-on dynistors with sharpening output circuits based on diode opening switches are considered. The results of an experimental study of a high-power generator incorporating such a dynistor; a step-up pulse transformer; and a high-voltage diode opening switch, which is an assembly of drift step-recovery diodes connected in series, are presented. The output voltage pulses of the generator with an amplitude of 45 kV, a duration of 50 ns, a rise time of 10 ns, and a repetition rate of 1 kHz are applied to a load resistance of 25 .