JP7364531B2 - electromagnetic accelerator - Google Patents

Description

The present invention relates to an electromagnetic accelerator.

A so-called coil gun is known as an electromagnetic accelerator that accelerates an object using electromagnetic force, which accelerates an object made of a conductor by passing a time-varying current through a coil to generate a magnetic field.

As an example of such a coil gun, a configuration has been proposed in which a plurality of acceleration coils are arranged in the direction of accelerating a metal flying object to continuously accelerate the flying object (Non-Patent Documents 1 and 2). In this configuration, when the accelerator coil is suddenly excited by passing current from the charged capacitor to the accelerator coil at the timing when the flying object passes through the center of the accelerating coil, an induced current is generated on the bottom surface of the flying object made of metal. flows. The flying object is accelerated by the magnetic field generated by this induced current repelling the magnetic field generated by the energization of the acceleration coil. By providing multiple stages of acceleration coils, the flying object can be accelerated to high speeds.

Zou Bengui, et.al., “Magnetic-Structural Coupling Analysis of Armature in Induction Coilgun”, IEEE Transactions on plasma science, vol.39, No.1, January 2011, pp.65-69. Tao Zhang, et.al., “Design and Evaluation of the Driving Coil on Induction Coilgun”, IEEE Transactions on plasma science, vol.43, No.5, May 2015, pp.1203-1207.

In the general coil gun mentioned above, a capacitor is used as a power source for supplying current to the accelerating coil, so the rise time t of the current in the accelerating coil is defined by the inductance L of the accelerating coil and the capacitance C of the capacitor. (t=π√LC/2). Therefore, as the flying object increases in speed, the current in the accelerator coil must rise quickly, and the capacitance of the capacitor that supplies the current must be reduced. However, reducing the capacitance of the capacitor reduces the amount of energy that can be stored, so the charging voltage must be increased.

In the configuration in which the accelerating coils are multi-staged as described above, the higher the speed of the flying object, the faster the accelerating coils are placed in later stages. Therefore, there is a problem that the capacitance of the capacitor that flows the current to the accelerating coil must be made smaller as the stage becomes later.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electromagnetic accelerator that accelerates an object to a higher speed by improving the rising speed of current in an accelerating coil.

Other objects and novel features will become apparent from the description of this specification and the accompanying drawings.

An electromagnetic accelerator according to a first aspect of the present invention includes a DC power source, an electromagnetic energy storage coil that is excited by supplying a DC current from the DC power source, and an electromagnetic energy storage coil that is excited by the DC power supply. an acceleration coil that accelerates an object to be accelerated in the axial direction by an induced magnetic field generated by a self-induced current being supplied from the electromagnetic energy storage coil when the supply of the direct current is cut off. be. Thereby, by supplying the self-induced current from the electromagnetic energy storage coil to the accelerating coil, it is possible to improve the rising speed of the current in the accelerating coil.

The electromagnetic accelerator according to a second aspect of the present invention is the electromagnetic accelerator described above, and includes a first switch connected in parallel with the accelerating coil between both ends of the DC power supply, and a first switch connected in parallel with the accelerating coil. a second switch connected in parallel to the acceleration coil and the first switch; and a second switch inserted between the first switch and the DC power supply. 3 switches, the electromagnetic energy storage coil is inserted into a path consisting of the first and second switches and the acceleration coil, and the second and third switches are closed; Opening the first switch to excite the electromagnetic energy storage coil; and after energizing the electromagnetic energy storage coil, closing the first switch and opening the second and third switches. , it is preferable that a self-induced current is supplied from the electromagnetic energy storage coil to the acceleration coil. This allows the current in the accelerating coil to rise at a high speed comparable to the switching speed of the switch.

The electromagnetic accelerator according to a third aspect of the present invention is the electromagnetic accelerator described above, wherein the first accelerating coil is connected in parallel to the plurality of accelerating coils connected in series between both ends of the DC power source. a plurality of second switches connected in parallel with each of the plurality of acceleration coils, and a third switch inserted between the first switch and the DC power supply, The electromagnetic energy storage coil is inserted into a path composed of the first switch, the plurality of second switches, and the plurality of acceleration coils, and is configured to connect the plurality of second switches and the third switch. close the first switch, open the first switch to energize the electromagnetic energy storage coil, and after energizing the electromagnetic energy storage coil close the first switch and open the third switch, It is preferable that the self-induced current is sequentially and alternatively supplied from the electromagnetic energy storage coil to each of the plurality of coils by sequentially and alternatively opening each of the second switches. . Thereby, the current of each of the plurality of acceleration coils can be raised at a high speed comparable to the switching speed of the switch.

The electromagnetic accelerator according to a fourth aspect of the present invention is the electromagnetic accelerator described above, and is connected to an accelerating coil provided at an end opposite to the acceleration direction of the object among the plurality of accelerating coils. By sequentially and selectively opening each of the plurality of second switches toward the acceleration coil provided at the end on the side in the acceleration direction, the plurality of acceleration The self-induced current is sequentially applied to each of the plurality of coils from an acceleration coil provided at an end of the coil opposite to the acceleration direction to an acceleration coil provided at an end of the coil on the acceleration direction side. And it is desirable that they be supplied selectively. This makes it possible to continuously accelerate an object using the plurality of acceleration coils.

An electromagnetic accelerator according to a fifth aspect of the present invention is the electromagnetic accelerator described above, and includes a plurality of sensors for detecting passage of the object, which are provided corresponding to each of the plurality of acceleration coils. Control for controlling the timing of opening the second switch connected to the acceleration coil corresponding to the sensor that detected the passage of the object, in response to the passage of the object detected by each of the plurality of acceleration sensors. It further has a section, which makes it possible to continuously accelerate the object by the plurality of acceleration coils.

An electromagnetic accelerator according to a sixth aspect of the present invention is the electromagnetic accelerator described above, in which n+1 electromagnetic energy storage coils are connected in series, where n is an integer of 2 or more, and n+1 electromagnetic energy storage coils are connected in series. Preferably, a second switch is inserted between two adjacent ones of the n+1 electromagnetic energy storage coils. Thereby, by increasing the number of electromagnetic energy storage coils arranged, a larger amount of electromagnetic energy can be stored.

An electromagnetic accelerator according to a seventh aspect of the present invention is the electromagnetic accelerator described above, which includes the DC power supply, the first and third switches, the plurality of second switches, and the electromagnetic energy storage coil. It is preferable that a plurality of current supply units configured of the above are provided, and among the plurality of current supply units, the second switches connected to the same acceleration coil are opened and closed at a constant time difference. Thereby, even larger electromagnetic energy can be stored, and a larger current can be supplied to the accelerating coil.

According to the present invention, it is possible to provide an electromagnetic accelerator that accelerates an object to a higher speed by increasing the rising speed of the current in the accelerating coil.

1 is a diagram schematically showing the basic configuration of an electromagnetic accelerator according to a first embodiment; FIG. FIG. 2 is a diagram schematically showing the principle of acceleration of an object. 1 is a diagram showing a more detailed configuration of an electromagnetic accelerator according to a first embodiment; FIG. FIG. 2 is a circuit diagram of an electromagnetic accelerator when accumulating electromagnetic energy. FIG. 2 is a circuit diagram of the electromagnetic accelerator when supplying current to a front-stage accelerating coil. FIG. 3 is a circuit diagram of the electromagnetic accelerator when supplying current to a subsequent accelerating coil. FIG. 2 is a diagram schematically showing the configuration of an electromagnetic accelerator according to a second embodiment.

Hereinafter, specific embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments. Further, in order to clarify the explanation, the following description and drawings are appropriately simplified. In addition, the same elements are given the same reference numerals, and redundant explanations will be omitted.

Embodiment 1
An electromagnetic accelerator according to Embodiment 1 will be described. FIG. 1 schematically shows the basic configuration of an electromagnetic accelerator 100 according to the first embodiment. In the following figures, a left-handed orthogonal coordinate system is used. In Figure 1, the horizontal direction from left to right on the paper is the Z direction (Z-axis), the vertical direction from the bottom to the top on the paper is the Y direction (Y-axis), and the paper normal direction from the front to the back of the paper. is defined as the X direction (X axis).

The electromagnetic accelerator 100 has a configuration in which a plurality of acceleration coils are arranged in a direction D of accelerating an object. In this example, n acceleration coils LA1 to LAn (where n is an integer of 2 or more) are arranged in an acceleration direction D (Z(+) direction) with the Z axis as the central axis. The electromagnetic accelerator 100 is configured as a repulsion type coil gun that accelerates the object PR by the electromagnetic force generated when current is passed through the n acceleration coils LA1 to LAn.

Although not shown, the acceleration coils LA1 to LAn may be installed, for example, inside a cylindrical member whose central axis is the Z-axis. The cylindrical member may have various shapes, such as a circle, an ellipse, and a polygon including a square, as long as it can hold the acceleration coils LA1 to LAn. Further, the cylindrical member may be provided with holes for weight reduction. Further, the acceleration coils LA1 to LAn may be held by a member having an arbitrary shape other than a cylindrical member.

FIG. 2 schematically shows the principle of acceleration of the object PR. In FIG. 2, for generalization, acceleration coils LA corresponding to each of acceleration coils LA1 to LAn are shown. When a current I is applied to the acceleration coil LA while the object PR is located on the side of the acceleration direction D with respect to the acceleration coil LA (the Z(+) side in FIG. 2, that is, the right side), it A magnetic field B is generated. As a result, an induced current EC flows through the object PR in a direction that cancels the magnetic field generated by the accelerating coil LA, and a magnetic field BA in the opposite direction to the magnetic field B is generated. As a result, a repulsive force F due to electromagnetic force is generated in the object PR in the direction away from the acceleration coil LA, that is, in the acceleration direction D.

In this configuration, the object PR can be efficiently accelerated by repeating the acceleration shown in FIG. 2 multiple times using the acceleration coils LA1 to LAn.

The electromagnetic accelerator 100 is configured to accelerate the object PR by supplying self-induced current generated by electromagnetic energy stored in the electromagnetic energy storage coil to the acceleration coils LA1 to LAn. The basic configuration of the electromagnetic accelerator 100 will be described below.

The electromagnetic accelerator 100 includes acceleration coils LA1 to LAn, a DC power supply 1, switches 2 and 3, electromagnetic energy storage coils L0 to Ln, and switches S1 to Sn. In the electromagnetic accelerator 100, the DC power supply 1, the switches 2 and 3, the electromagnetic energy storage coils L0 to Ln, and the switches S1 to Sn form a current supply unit 10 that selectively supplies current to the acceleration coils LA1 to LAn. It consists of

As described above, the acceleration coils LA1 to LAn are arranged in parallel in the acceleration direction D so that their central axes are parallel to the Z-axis.

Between the positive and negative electrodes of the DC power source 1, a switch 2 (also referred to as a third switch) and electromagnetic energy storage coils L0 to Ln are connected in series in this order.

When k is an integer from 1 to n, a switch Sk is inserted between the electromagnetic energy storage coil L(k-1) and the electromagnetic energy storage coil Lk.

The node between the electromagnetic energy storage coil L(k-1) and the switch Sk is connected to one end of the acceleration coil LAk, and the node between the electromagnetic energy storage coil Lk and the switch Sk is connected to the other end of the acceleration coil LAk. is connected to.

A switch 3 (also referred to as a first switch) is inserted between the negative electrode of the DC power supply 1 and a node between the switch 2 and the electromagnetic energy storage coil L0.

The opening and closing of the switches S1 to Sn (each also referred to as a second switch) is controlled by applying control signals C1 to Cn to the switches S1 to Sn. As described later, the control signals C1 to Cn are provided, for example, by a control section.

The configuration shown in FIG. 1 is the basic configuration of the electromagnetic accelerator 100, and it is also possible to add desirable elements and configurations to fulfill the function as an electromagnetic accelerator. FIG. 3 shows a more detailed configuration of the electromagnetic accelerator 100 according to the first embodiment.

As shown in FIG. 3, the switch Sk may include a semiconductor switch Mk and a metal contact electromagnetic relay RLk connected in parallel. As the semiconductor switch Mk, various transistors such as a MOSFET (metal-oxide-semiconductor field-effect transistor) or a bipolar transistor may be used. Further, the semiconductor switch Mk connects the electromagnetic energy storage coil L(k-1) and the electromagnetic energy storage coil Lk with appropriate polarity according to the direction of the current flowing through the coil provided in the electromagnetic accelerator 100. connected between.

The semiconductor switch Mk is provided together with the metal contact type electromagnetic relay RLk, and is provided as a high-speed switch that reduces resistance loss of the semiconductor switch Mk. A control signal Ck is applied from the control section 4 to the semiconductor switch Mk as a pulsed signal. Thereby, when the semiconductor switch Mk is closed, the metal contact type electromagnetic relay RLk can be closed, and when the semiconductor switch Mk is opened, the metal contact type electromagnetic relay RLk can be opened. This makes it possible to open and close the switches S1 to Sn.

By configuring each of the switches S1 to Sn using the metal contact type electromagnetic relays RL1 to RLn, a large current can flow through the switches S1 to Sn. This allows a large current to flow through the electromagnetic energy storage coils L0 to Ln, allowing electromagnetic energy to be stored efficiently.

Further, as shown in FIG. 3, diodes DA1 to DAn and DB1 to DBn for preventing reverse current may be provided. The anode of the diode DAk is connected to the electromagnetic energy storage coil L(k-1), and the cathode is connected to the acceleration coil LAk. The diode DBk has an anode connected to the electromagnetic energy storage coil Lk, and a cathode connected to the electromagnetic energy storage coil L(k-1).

Further, sensors 5_1 to 5_n for detecting passage of the object PR may be provided in front of the acceleration coils LA1 to LAn, that is, on the Z(-) side, respectively. When the object PR passes in the acceleration direction D, the sensors 5_1 to 5_n output timing signals T1 to Tn, respectively, to the control unit 4. The control unit 4 controls the timing of selectively opening each of the switches S1 to Sn by controlling the output timing of the control signals C1 to Cn according to the timing signals T1 to Tn. This makes it possible to control the timing of supplying current to each of the acceleration coils LA1 to LAn.

Hereinafter, the acceleration operation in the electromagnetic accelerator 100 will be explained. FIG. 4 shows a circuit diagram of the electromagnetic accelerator 100 when accumulating electromagnetic energy. As shown in FIG. 4, in order to store electromagnetic energy in the electromagnetic energy storage coils L0 to Ln, the coil excitation switch 2 and the switches S1 to Sn are closed, and the current circulation switch 3 is opened. As a result, the DC current I1 flows through the electromagnetic energy storage coils L0 to Ln to excite them, and electromagnetic energy is accumulated.

Next, the energy stored in the electromagnetic energy storage coils L0 to Ln supplies current to the acceleration coils LA1 to LAn. FIG. 5 shows a circuit diagram of the electromagnetic accelerator 100 when supplying current to the accelerating coil LA1. In this case, as shown in FIG. 5, the switch 3 for current circulation is closed and the switch 2 for coil excitation is opened. As a result, a loop-shaped circuit is formed in which the DC power supply 1 is separated from the circuit and the electromagnetic energy storage coils L0 to Ln are connected in series. In this circuit, when the current supply from the DC power supply 1 is cut off, a self-induced current I2 is generated by the electromagnetic energy storage coils L0 to Ln. This self-induced current I2 is a current in the same direction as the direct current I1.

In this state, when the switch S1 is opened and the other switches S2 to Sn are kept closed, a self-induced current I2 flows through the acceleration coil LA1, and a magnetic field B1 in the acceleration direction D is generated. As a result, the object PR placed closer to the acceleration direction D than the acceleration coil LA1 is accelerated in the acceleration direction D by the repulsive force F1, as described above.

Thereafter, a current is supplied to the acceleration coil LA2 at a timing when the object PR moves further in the acceleration direction D than the acceleration coil LA2. FIG. 6 shows a circuit diagram of the electromagnetic accelerator 100 when supplying current to the accelerating coil LA2. As shown in FIG. 6, by closing the switch S1 and opening only the switch S2 at the timing when the object PR moves to the side in the acceleration direction D rather than the acceleration coil LA2, a self-induced current I2 flows through the acceleration coil LA2, causing acceleration. A magnetic field B2 oriented in direction D is generated. As a result, the object PR located closer to the acceleration direction D than the acceleration coil LA2 is further accelerated in the acceleration direction D by the repulsive force F2.

After that, the object PR can be accelerated by opening only the switch corresponding to each accelerating coil and closing the other switches at the timing when the object PR has moved further in the acceleration direction D than each subsequent accelerating coil. can.

With this configuration, the rise of the current (self-induced current I2) supplied to the coil can be accelerated to a time that depends on the switching time of the switches S1 to Sn. As shown in FIG. 3, when a semiconductor switch is used as the switch, it is possible to speed up the rise of the current up to the switching time defined by the withstand voltage characteristics of the semiconductor switch.

As a result, it can be understood that the current supplied to the accelerating coil rises rapidly regardless of whether the accelerating coil is disposed in the front stage or the rear stage. Moreover, unlike the case where current is supplied from a capacitor, the rise of the current is not restricted by the LC resonance condition, so it is possible to accelerate the object to a higher speed than with a general coil gun.

Further, since it is possible to supply a current of approximately the same magnitude to each acceleration coil, it is also possible to equalize the acceleration given to the object PR by each acceleration coil.

Each of the switches S1 to Sn can be opened and closed at desired timing by the control unit 4, so that current can be supplied to appropriate accelerator coils in accordance with the movement of the object PR. Thereby, it becomes possible to continuously accelerate the object PR by each of the plurality of acceleration coils.

Furthermore, in this configuration, since the current in the accelerating coil rises quickly, the induced magnetic field also becomes stronger, making it possible to accelerate the object more efficiently and to a higher speed.

Embodiment 2
In the first embodiment, the electromagnetic accelerator 100 is provided with one current supply section 10 in which the electromagnetic energy storage coils L0 to Ln are connected in a line. In contrast, in this embodiment, a configuration will be described in which the electromagnetic energy stored can be increased by arranging current supply units in parallel.

FIG. 7 schematically shows the configuration of an electromagnetic accelerator 200 according to the second embodiment. In the electromagnetic accelerator 200, m (m is an integer of 2 or more) current supply sections 10_1 to 10_m having the same configuration as the current supply section 10 are arranged in parallel.

Here, j is an integer between 0 and m. DC power supply 1_j, switch 2_j, switch 3_j, electromagnetic energy storage coils L0_j to Ln_j, switches S1_j to Sn_j, and diodes DA1_j to DAn_j of current supply unit 10_j are DC power supply 1, switch 2, and switch of current supply unit 10, respectively. 3. Corresponds to electromagnetic energy storage coils L0 to Ln, switches S1 to Sn, and diodes DA1 to DAn.

Further, in the current supply unit 10_j, a diode DCk_j for preventing reverse current is provided between the acceleration coil LAk and the electromagnetic energy storage coil Lk_j. The anode of the diode DCk_j is connected to the acceleration coil LAk, and the cathode is connected to the electromagnetic energy storage coil Lk_j.

Control signals C1_j to Cn_j are applied from the control unit 4 to the switches S1_j to Sn_j. The control unit 4 simultaneously opens and closes the switches Sk_1 to Sk_m corresponding to one acceleration coil LAk using the control signals Ck_1 to Ck_m, thereby converting the self-induced currents generated in the m current supply units 10_1 to 10_m into one It can be supplied to the acceleration coil LAk.

As described above, according to this configuration, current can be supplied from m current supply units to one acceleration coil, so that the magnetic field generated by one acceleration coil can be strengthened. This allows objects to be accelerated to even higher speeds.

Other Embodiments The present invention is not limited to the above embodiments, and can be modified as appropriate without departing from the spirit. For example, only one accelerating coil may be provided, or two or more accelerating coils may be provided.

The configurations of the switches S1 to Sn are not limited to the example shown in FIG. 3, and may have various configurations.

1 DC power supply 2 Switch 3 Switch 4 Control unit 100 Electromagnetic accelerator C1~Cn Control signal D Acceleration direction DA1~DAn, DB1~DBn Diode EC Induced current F Repulsion I Current I1 DC current I2 Self-induced current L0~Ln Electromagnetic energy storage Coil LA1~LAn Acceleration coil M1~Mn Semiconductor switch PR Object RL1~RLn Metal contact type electromagnetic relay S1~Sn Switch

Claims (7)

DC power supply and
an electromagnetic energy storage coil that is excited by being supplied with DC current from the DC power supply;
When the supply of the direct current to the excited electromagnetic energy storage coil is cut off, the induced magnetic field generated by the self-induced current supplied from the electromagnetic energy storage coil causes the object to be accelerated in the axial direction. An acceleration coil that accelerates;
Electromagnetic accelerator. a first switch connected in parallel with the acceleration coil between both ends of the DC power supply;
a second switch connected in parallel to the acceleration coil and the first switch between the acceleration coil and the first switch;
a third switch inserted between the first switch and the DC power supply,
The electromagnetic energy storage coil is inserted into a path composed of the first and second switches and the acceleration coil,
closing the second and third switches and opening the first switch to energize the electromagnetic energy storage coil;
After energizing the electromagnetic energy storage coil, the first switch is closed and the second and third switches are opened, so that a self-induced current is supplied from the electromagnetic energy storage coil to the acceleration coil. ,
The electromagnetic accelerator according to claim 1. a first switch connected in parallel to the plurality of acceleration coils connected in series between both ends of the DC power supply;
a plurality of second switches connected in parallel with each of the plurality of acceleration coils;
a third switch inserted between the first switch and the DC power supply,
The electromagnetic energy storage coil is inserted into a path composed of the first switch, the plurality of second switches, and the plurality of acceleration coils,
Close the plurality of second switches and the third switch, open the first switch, and energize the electromagnetic energy storage coil;
After the electromagnetic energy storage coil is energized, the first switch is closed, the third switch is opened, and each of the plurality of second switches is sequentially and selectively opened, so that the electromagnetic energy storage coil is energized. The self-induced current is sequentially and selectively supplied to each of the plurality of acceleration coils from the energy storage coil.
The electromagnetic accelerator according to claim 1. From the second switch connected to an acceleration coil provided at an end of the plurality of acceleration coils on the opposite side to the acceleration direction of the object to an acceleration coil provided at the end on the side in the acceleration direction. by sequentially and selectively opening each of the plurality of second switches toward the
The self-induced current accelerates the plurality of acceleration coils from the acceleration coil provided at the end opposite to the acceleration direction to the acceleration coil provided at the end on the acceleration direction side among the plurality of acceleration coils. supplied to each of the coils in turn and alternatively;
The electromagnetic accelerator according to claim 3. a plurality of sensors for detecting passage of the object, provided corresponding to each of the plurality of acceleration coils;
A control unit that controls timing to open the second switch connected to the acceleration coil corresponding to the sensor that detected the passage of the object, in accordance with the passage of the object detected by each of the plurality of sensors . and further comprising,
The electromagnetic accelerator according to claim 4. Let n be an integer of 2 or more,
n+1 electromagnetic energy storage coils are connected in series,
The n second switches are inserted between two adjacent ones of the n+1 electromagnetic energy storage coils,
The electromagnetic accelerator according to any one of claims 3 to 5. A plurality of current supply units each including the DC power supply, the first and third switches, the plurality of second switches, and the electromagnetic energy storage coil are provided,
Among the plurality of current supply units, the second switches connected to the same acceleration coil are opened and closed at a constant time difference,
The electromagnetic accelerator according to any one of claims 3 to 6.

Images