RU22597U1 - POWERFUL SEMICONDUCTOR GENERATOR - Google Patents

Abstract

A powerful semiconductor generator comprising a power circuit from a series-connected power capacitive energy storage device, a reversibly switched dinistor connected by the anode to the positive terminal of the power capacitive storage device, and a cathode to the beginning of the secondary winding of the transformer with a saturable core, and the load and the start circuit connected to the primary transformer winding, containing in series connected starting capacitive energy storage, connected negatively to the end of the primary transformer windings, and the key, characterized in that the generator further introduced drift recovery diodes connected in parallel with the load so that its anode connected to the negative terminal of said power storage capacitor.

Description

POWERFUL SEMICONDUCTOR GENERATOR.

The proposed utility model relates to the field of pulsed technology, more precisely to the generation of electrical pulses, and can be used, for example, in electric discharge cleaning systems for industrial gas emissions, in which for reliable and safe operation it is necessary to generate powerful current pulses of long duration with a short rise time .

For the formation of powerful, but short current pulses (nanosecond range of duration), there are currently powerful semiconductor generators based on drift diodes with sharp recovery (DDRV) 1. Their principle of operation is based on the effect of the fast recovery of the blocking ability of the DDRV when changing the polarity of the current in the power circuit , consisting of series-connected DDRV, ind5ivostnosti and power capacitor. First, a short (not more than 300-400 nanoseconds) direct current pulse 1u with a density of not more than 100 amperes per square centimeter of the working area of the DDRV is passed through the power circuit. This current creates a sharply inhomogeneous distribution of the electron-hole plasma in the p-base of the diode and provides the charge of the power capacitor. Then a short reverse current pulse passes through the DDRV, which is the discharge current of the power capacitor. At the time of maximum reverse current, the p-base of the DDRV is completely freed from the charge of minority carriers accumulated during the passage of forward current 1u. In this case, the DDRV transition is displaced in the locking direction, and the resulting space charge region expands in the p-base due to the removal of the main carriers (electrons) from the diode structure. The ratio between the density of the reverse current and the concentration of the main carriers in the base is chosen so as to ensure the movement of electrons with the maximum possible speed (10 cm / sec). The result is a very fast (in a few nanoseconds) current flow in the DDRV and the current switching of the power circuit into a parallel connected load.

The disadvantage of generator 1 is the short duration of the power current pulses switched into the load (significantly less than one microsecond), due to the small amount of charge Q accumulated in the power capacitor at

current passage ly. The small value of the charge Q is determined by the essentially short duration of the current 1u and the relatively small amplitude of this current, due to the small value of the maximum permissible current density through the DDRV.

Also known is a powerful semiconductor generator based on a reversibly switched dinistor (RVD) 2, taken as a prototype. It contains a power circuit consisting of a series-connected RVD, a power capacitive energy storage device and a secondary winding of a transformer with a saturable core, as well as a load and a start circuit connected to the transformer primary winding and consisting of a series starting capacitive storage device and a key. When the start circuit key is turned on, a short voltage pulse appears on the secondary side of the transformer, the amplitude of which exceeds the value of the charge voltage of the power storage device. At the same time, a reverse current pulse of 1u passes through the WFD, which ensures the accumulation in its structure of the control charge necessary for subsequent switching. At the time of saturation of the core of the transformer, a direct voltage is applied to the RVD, it switches without delay and switches the power current pulse, which is the discharge current of the power storage device, to the load. If the magnitude of the control charge is sufficiently large, then the WFM switches uniformly over the area of its structure and with very low energy losses, which ensures high switching capabilities of the WFD during switching of rapidly growing power current pulses. Since the RVD is a thyristor type device, the duration of the power current passing through the RVD after its switching is determined only by the value of the charge Q stored in the power capacitive storage in the initial state. In the generator under consideration, in contrast to the analog device, there are no physical restrictions on the duration of the charging process and the magnitude of the charging current of the power capacitive storage, and the charge Q can be very large. In this case, the duration of the pulse of the power current switched to the load can be tens or hundreds of microseconds.

The disadvantage of the prototype device is the relatively long duration of the front of the rise of the switching current pulse of the power current of at least several hundred nanoseconds. It is determined by the sufficiently long duration of the process of establishing stationary conductivity in the WFD due to the relatively low diffusion rate of the carriers filling the base areas of the WFD during the switching of the power current.

Thus, existing high-power semiconductor generators cannot provide a combination of a short (nanosecond) rise front with a large (microsecond) duration of power current pulses switched to a load, which is necessary when operating electric gas discharge cleaning systems using powerful pulse generators. In these systems, it is necessary to increase the uniformity of the passage of current in the corona discharge of the gas gap in order to eliminate the possibility of spark breakdown leading to an emergency, for which it is necessary to increase the efficiency of the impact on the load, i.e. switching pulses with a sharp increase in the front and a long duration.

The objective of the proposed utility model is the creation of a powerful semiconductor generator that provides increased reliability and safety of operation of electric discharge gas cleaning systems by increasing the efficiency of the impact on physical activity.

The problem is solved in that in a powerful semiconductor generator that includes a power circuit from a series-connected power capacitive energy storage device, a reversibly switched dynistor connected by an anode to the positive terminal of the power capacitive storage device, and a cathode to the beginning of the secondary winding of a transformer with a hanging core, and the load, and starting circuit connected to the primary winding of the transformer, containing serially connected starting capacitive energy storage connected negative m output to the end of the primary winding of the transformer, and the key, an additional drift diode with a sharp recovery is added to the generator, connected in parallel with the load so that its anode is connected to the negative terminal of the said capacitive storage device.

The electrical circuit of the proposed utility model is presented in Fig., Where:

1-power capacitive energy storage;

2- reversibly included dinistor;

3-secondary transformer winding;

4-load;

5- primary winding of the transformer;

6-starting capacitive energy storage;

7-key;

 In the initial state, the power non-volatile energy storage device 1 and the starting capacitive storage device 6 are charged with the one indicated in FIG. polarity. When you turn on the key 7 on the secondary winding 3 of the transformer with a saturable core, a short (300-400 ns) voltage pulse appears, the amplitude of which exceeds the value of the charge voltage of the drive 1. As a result, a short pulse passes through the WFD 2 in the reverse direction and through the DDRV 8 current pulse 1y, providing the accumulation of charge of the electron-hole plasma in their structures. At the time of saturation of the core of the transformer, a direct voltage is applied to the RVD 2, it switches without delay and switches the pulse of the discharge current of drive 1 into the secondary winding 3 of the transformer, which increases during 200-300 NS. This current passes through DDRV 8 in the opposite direction and ensures the complete liberation of the p-base of the diode from the plasma accumulated during the passage of the current pulse 1y. As a result, DDRV 8 quickly recovers its locking ability. In this case, the power current passing through DDRV 8 abruptly breaks off and is switched to load 4. The duration of the rise front of the current in load 4 is determined by the interruption time of the current in DDRV 8 and amounts to several nanoseconds. After a current interruption in the DDDRV 8, the circuit slowly discharges the power storage device 1 through the high pressure switch 2, the secondary winding 3 of the transformer and load 4. At the same time, a power current pulse passes through load 4, the duration of which is determined by the amount of charge Q accumulated in drive 1. Since the principle of operation of the generator does not impose restrictions on the value of the charge Q, the duration of the pulse of the power current switched to the load can be very large tens or hundreds of microseconds.

Example.

For conducting experiments according to the circuit of FIG. A semiconductor pulse generator was manufactured. As drives 1 and 6, capacitor banks with a capacity of 500 nF and 6.6 nF were used, respectively, as a key 7 - a hydrogen thyratron TGI1-270 / 12, as a load 4 - a set of TVO type resistors with a total resistance of 10 Ohms. The core of the transformer was made of ferrites of the NMS-2500 type and had a size of 40x30x80 mm. Windings 3 and 5 of the transformer were made of coaxial cable RK - 50 and had 6 turns. The key RVD 2 consisted of four series-connected reversibly switched dynistors with a structure diameter of 10 mm and an operating voltage of 1000 V. The DDRV key 8 was made of four series-connected diodes with a structure diameter of 24 mm and an operating voltage of 1000 V. Charge voltage

) 5T

- 4

drive 1-3 kV, drive 6-9 kV. During experiments at load 4, voltage pulses with an amplitude of 3 kV and a rise front of -12 NS were formed. and duration of -15 μs. The pulse repetition rate of 100 Hz.

Compared with the prototype, the duration of the pulse front decreased by about an order of magnitude for the same duration of the pulse itself, which proves a significant increase in the efficiency of the impact on the load and, thereby, increasing the safety and reliability of operation of systems containing the proposed generator.

ioo- / y & f f

- 5 Literature. 1. Patent No. 2009611, Bull. Inventions No. 5,1994

2. Ж .. Electrical engineering, No. 3.1986, p. 44, Fig. 2, scheme b, Energoatomizdat.

Claims (1)

A powerful semiconductor generator that includes a power circuit from a series-connected capacitive energy storage device, a reversibly switched dinistor connected by the anode to the positive terminal of the capacitive storage device, and a cathode to the beginning of the secondary winding of the transformer with a saturable core, and the load and the start circuit connected to the primary transformer winding, containing in series connected starting capacitive energy storage, connected negatively to the end of the primary transformer windings, and the key, characterized in that the generator further introduced drift recovery diodes connected in parallel with the load so that its anode connected to the negative terminal of said power storage capacitor.