RU2331979C1 - Source of pulse magnetic field - Google Patents

Abstract

FIELD: electricity; physics.

SUBSTANCE: source of pulse magnetic field includes power supply, power switch, current distributor, current generator startup unit, storage capacitors, current generators, field-forming system, which contains no less than two solenoids and control switch. Field-forming system is available in two options. First design provides for all solenoids having equal length and being placed into each other so that lead-outs of start of winding are available from side of the system, whereas lead-outs of winding ends are available from the other side. In the second design, all solenoids have equal axial hollow and are placed end-to-end and in axial alignment with longitudinal line of field-forming system so that lead-out of start of one solenoid winding is arranged near lead-out of the other solenoid winding end. Power supply is connected to common bus (ground) and to current distributor input and current generator startup unit input via serial connection of power switch. Each current distributor output is coupled with one storage capacitor having output linked with common bus. Current generators are connected in parallel to storage capacitors. Windings of field-forming system throttles are connected in parallel to current generators diodes. Control signal outputs of generator startup unit are linked with control inputs of current generators, startup unit control switch being connected to input and output of current generator startup unit control.

EFFECT: generation of unidirectional periodic pulses of magnetic field of high intensity; possibility of increasing pulse magnetic field energy and reduction of unit dimensions and weight.

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Description

The invention relates to the field of producing pulsed magnetic fields of high energies when feeding an inductive load from a shock generator.

State of the art

A known pulse generator of a magnetic field (Aut. St. No. 491197, H03K 17/64, Bull. No. 41, 05.11.75.), Which contains a trigger unit connected to the inputs of two pulse generators, each of which is connected respectively to the strip line and Helmholtz rings. Helmholtz rings and the strip line are inductively interconnected, which ensures the expansion of the limits of change of the magnetic field.

The disadvantages of this generator are:

- low efficiency (less than 30%) due to the use of two pulse generators simultaneously, connected by one trigger unit through an inductively coupled strip line with Helmholtz rings, which requires accurate time synchronization of the EMF of two generators, the achievement of which is a difficult task;

- the need to introduce an additional pulse generator to expand the limits of the magnetic field, which leads to the additional use of high-speed devices for comparing the amplitudes of the pulses of both generators;

- the device can only be used in laboratory conditions;

- does not provide the possibility of increasing the energy of the pulsed magnetic field.

Also known is a method of transferring energy to an inductive load from a shock generator and a device for its implementation (Aut. St. No. 192922, H03K 17/64, Bull. No. 6, 02.03.1967). This device is taken as a prototype of the invention. It consists of a current generator, inductive load - a solenoid, a block of storage capacitors and two contact-gate switches. The current generator through the contact of one switch is connected in parallel with a capacitor bank, which is also connected in parallel with the solenoid through the contact of the second switch. The disadvantages of this device are:

- does not provide the possibility of increasing the energy of the pulsed magnetic field;

- the need to connect to the generator a pre-charged capacitor bank to which the load is connected, which leads to the need for accurate synchronization of the generator EMF and the voltage on the capacitor bank;

- the need to use high-speed comparison devices at certain points in time of the voltage on the capacitor bank and generator;

- the service life of the device is limited by the service life of contact-valve arcless switching devices (mechanical switches);

- low efficiency (25%) of the shock generator, which can be increased (due to accurate synchronization of the switching moments of the keys K1 and K2 only by 10-12%;

- the large dimensions and mass of the shock generator and the capacitor bank do not allow the device to be used outside of laboratory conditions.

The technical result of the invention

The technical result of the invention is the creation of unipolar periodic pulses of a magnetic field of high intensity, providing the possibility of increasing the energy of a pulsed magnetic field and reducing the size and weight.

Description of figures and symbols

Figure 1 presents the electrical circuit of the source of the pulsed magnetic field.

Figure 2a shows a longitudinal axial section of a field-forming system of a first embodiment.

On figb presents a longitudinal axial section of the field-forming system of the second variant of its execution.

Figure 3 presents a graph of the dependence of the intensity of the pulsed magnetic field over time in the cross section of the cavity of the field-forming system.

Figure 4 presents graphs of changes in the voltage Uk on the capacitor when it is charged over time from t ₀ to t1 and discharge - from t ₁ to t ₂ and the magnetic field strength N during discharge of the capacitor, where t ₀ is the moment of switching on the switch VP2, t ₁ - the moment of turning on the switch B12, t ₂ - the moment of the complete discharge of the capacitor.

Figure 5 presents the plot of the intensity of the total magnetic field along the cavity axis of the field-forming system of the first embodiment, where H _∑ is the total intensity of the magnetic fields of the two solenoids (the longitudinal section of the cavity is shown by a dotted line).

Figure 6 shows plots of the intensity of magnetic fields along the axis of the cavity of the second embodiment of its field-forming system, where H ₁ is the plot of the intensity of the magnetic field along the axis of the cavity of the first solenoid, H ₂ is the same along the axis of the cavity of the second solenoid, H _∑ is the plot of intensity total magnetic field along the axis of the cavity of the field-forming system (the longitudinal section of the cavity is shown by a dotted line).

The following notation is introduced in the figures:

1 - power source; 2 - power switch; 3 - distribute current; 4 - start block current generator; 5 - the first storage capacitor; 6 - the second storage capacitor; 7 - the first current generator; 8 - second current generator; 9 - field-forming system; 10 - the first solenoid; 11 - the second solenoid; 12 - control switch; 13 and 14 - distribution diodes; 15 and 16 - diodes; 17 and 18 - thyristors; 19 - resistor voltage divider; 20 - current limiting resistor; 21 - a zener diode; 22 - electrolytic capacitor; 23 - solid state relay; 24 and 25 - resistors of the voltage divider.

The device source of a pulsed magnetic field

The technical result of the invention is achieved due to the fact that the source of pulsed magnetic fields contains (Fig. 1): power supply (PI) 1, power switch (VP) 2, distribute current (RT) 3, start-up block of current generator (BZG) 4, storage capacitors (NK) 5 and 6, current generators (GT) 7 and 8, field-forming system (PS) 9, which includes at least two solenoids (C) 10 and 11 and a control switch (B) 12.

The constant voltage source IP1 has two outputs: plus (1) and minus (2). The VP2 power switch also has two outputs (1) and (2).

The current distributor RTZ has a power input (1) and at least two equivalent current outputs (2) and (3). An increase in the current outputs in the RTZ current distributor makes it possible to infinitely increase the power of the pulsed magnetic field source due to additional storage capacitors of the NK and GT current generators, which are connected in parallel with the capacitors.

The start block of the BZG4 generator has a power input (1) and control signal outputs (2) and (3) and an input (5) and an output (6) of the control of the start block.

The switch control unit of the launch unit B 12 has two outputs (1) and (2).

In the field-forming system PS9, the solenoids C10 and C11 have the same direction of winding their windings and are made on a dielectric frame with a cavity of round or rectangular cross section. The solenoid windings have two conclusions: (1) the beginning of the winding and (2) the end of the winding (figure 1). Solenoids are collected in a field-forming system so that the magnetic field vectors of all solenoids lie on the longitudinal axis of the system and are directed in one direction.

The field-forming system PS9 can be performed in two versions.

1st embodiment PS9. In this embodiment (figa), all solenoids have the same length and are placed one in the other (on the principle of "Matryoshka") and so that the terminals of the beginning of their windings are located at one end of PS9, and the terminals of the ends are from the other. A solenoid in which the smallest transverse dimensions of the axial cavity have external dimensions equal to the transverse dimensions of the axial cavity of the solenoid located outside the first solenoid.

2nd embodiment PS9. In this embodiment (fig.2b), all solenoids have an axial cavity of the same size, placed end-to-end one after another and coaxially to the longitudinal axis of PS9 and so that the output of the start of one winding of one solenoid is located at the output of the end of the winding of the other solenoid.

Pulsed magnetic field source device connections

The minus (2) of the IP1 power source is connected to a common bus (ground), and its plus (1) is connected through a series-connected power switch VP2 to the power inputs of the RTZ and BZG4 (Fig. 1).

Each output of the PT3 current distributor is connected to one output of the NK storage capacitor, the second output of which is connected to a common bus.

In parallel with the storage capacitors, GT7 and GT8 current generators are included, which contain a diode (15 or 16) and a thyristor (17 or 18) connected in series.

Parallel to the diodes of the GT current generators, the windings of the solenoids C10 and C11 of the field-forming system are included.

The outputs (2) and (3) of the control signal of the start block of the BZG4 generators are connected to the control inputs (2) (with the control electrodes of the thyristors) of the GT current generators.

The switch B 12 control unit of the launch is connected to the input (5) and output (6) of the control unit of the start of the current generators BZG4.

Operation of a pulsed magnetic field source

After turning on the switch VP2 to the inputs of the current distributor RT3 and the start block of the generators BZG4 receives a constant voltage from the power source IP1 (figure 1). The PT3 current distributor provides an equal distribution of currents in its circuits to ensure the operation of GT7 and GT8 current generators and storage capacitors NK5 and NK6 with the same power mode. Storage capacitors NK5 and NK6 through diodes 13 and 14 are charged to the voltage value of the power source IP1. To obtain pulses that control the operation of the GT7 and GT8 current generators at the time of switching on the B12 switch, the power supply unit is supplied to the start unit of the BZG4 generators, at the input of which a voltage divider made on resistors 19 and 20 provides a proportional voltage division between the control pulse generation circuit, GT7 and GT8 current generators and the control circuit of the start blocks of the BZG4 generator. From the divider through the current-limiting resistor 20, the current is supplied to the stabilizer voltage 21, from which the stabilized voltage is supplied to the normally open contacts (NOC) of the solid-state relay 23.

When the control switch B 12 is turned on, the power circuit is closed and current flows through the control circuit of the start unit of the current generators BZG 4, which creates a pulse in the threshold element (included in the solid-state relay) to switch the solid-state relay 23 of the solid-state relay to the closed position. This inclusion provides high-impedance isolation on the control circuits, eliminates the interference of electromagnetic fields on the control circuit and ensures electromagnetic compatibility of the circuit elements in their compact arrangement. From the output of the relay 23 through the resistor 24 of the voltage divider, the generated control signal simultaneously from the outputs (2) and (3) of the start block of the current generator BZG4 is fed to the inputs (2) of the current generators GT7 and GT8, through which the NK5 capacitors are discharged to the solenoids C10 and C11 and NK6, respectively. As the current strength in these circuits increases (Figs. 3 and 4), the voltage across the NK5 and NK6 capacitors decreases, due to the flowing pulsed current of a large value in the solenoids C10 and C11, a pulsed unipolar magnetic field is formed with the same direction of the magnetic field vector, which in the field-forming system, PS9 is summarized (Figs. 5 and 6).

When the maximum current is reached, the electromotive force of the solenoids changes polarity, forming a control signal, which is fed to the current generators GT7 and GT8, the first input of which (1) opens the diodes 15 and 16. Then the current flows through the diodes 15 and 16 and closes the thyristors 17 and 18 respectively.

The process begins to repeat, the charge of the capacitors NK5 and NK6 begins again. The period of operation of the magnetic field source depends on the time constant of the capacitor charge circuit, which includes IP1-VP2-RT3-NK1 (NK2). This process is repeated many times until the power switch VP2 is turned off.

When GT7 and GT8 current generators are started in a short period of time, which is determined by the time constant of the capacitor discharge circuit (not more than 10 ms), pulsed currents of large values flow through thyristors 17 and 18 and diodes 15 and 16, which leads to the creation of a pulsed magnetic field, the value the intensity of which in the field-forming system depends on the design of this system and the time constant of the charge and discharge circuit of the capacitors.

An example of a pulsed magnetic field source

The source of the pulsed magnetic field was made according to the scheme of figure 2, in which the following components are used.

The current generator is made on a thyristor type 2T143-500-16 and a diode 2D133-500-26. The starting block of the current generators is made on a solid state relay of the type КР293КП11АП, a zener diode of the type КС515А and an electrolytic capacitor of the type К50-16. Control switch type P2KnT4-2V.

DC voltage source B5-71 (ratings: voltage from 0 to 30 V and current from 0 to 10 A). Power switch - TV 1-2 type tumbler. Current separator - diodes type KD 257 A. Storage capacitors type K50-77.

The field-forming system is made according to the first embodiment, in which cylindrical solenoids C10 and C11 are used, in which the internal diameters are 97 mm and 100 mm, respectively. The length of the solenoids is 150 mm. The outer diameter of the inner solenoid is equal to the inner diameter of the outer solenoid. The number of turns of each solenoid is 50, the cross section of the copper wire of the winding is 3 sq. Mm. The winding of the solenoid winding is made in one direction in one layer.

The prototype of the source of the pulsed magnetic field had the technical characteristics:

- current in the pulse of the current generator 50,000 A;

- the intensity of the magnetic field in each solenoid 210,000 E.

The device makes it possible to increase the magnetic field intensity almost unlimitedly by increasing the number of parallel channels in the current distributor using appropriate power sources and spatial summation of vectors of magnetic field strength of the same direction created by solenoids.

Claims (1)

A pulsed magnetic field source containing a constant voltage power source, a current generator, a storage capacitor, two current commutators and a field-forming system consisting of one solenoid, one terminal of the current generator being connected to one terminal of the capacitor, one terminal of the solenoid, and a common bus, characterized in that at least one current generator and at least one storage capacitor, at least one solenoid are introduced into the field-forming system, distribute the current and the control switch, the first the current switch is made in the form of a power switch, and the second in the form of a unit for starting current generators, in addition, the current distribution has a power input and outputs according to the number of current generators that have power inputs, current outputs and control signal inputs, the current generator start unit has an input power supply, control signal outputs, and in the field-forming system, the solenoids are placed coaxially one inside the other or one after another, in addition, the negative terminal of the power source is connected to the common bus, and the positive terminal is connected via the power switch dinene with power inputs of the current distributor and the start block of the current generators, each output of the current distributor is connected to one terminal of one capacitor, the power input of one current generator and one terminal of the winding of one solenoid, the other terminal of the introduced capacitor and the output of the introduced current generator are connected to a common bus, and the current generator current output is connected to the other output of the solenoid winding, the control output of each current generator is connected to the control signal output of the generator start block, its input and output is ION coupled to the control terminal of the switch.

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