CN103116157B - Plasma sonar buoy - Google Patents

Abstract

The invention discloses a plasma sonar buoy, which comprises a low-voltage module and a high-voltage module connected thereto; the low-voltage module includes a positioning unit, a communication unit and an energy storage unit; the high-voltage module includes a DC-DC conversion unit and a pulse discharge unit. The invention adopts pulsed plasma corona discharge technology in water, which has long service life, good sound source stability, no multiple oscillations of pulsed sound waves, high repeatability, high source level and wide frequency band, and its main working frequency band can be adjusted from hundreds of Hz To several thousand Hz, which is lower than the frequency of piezoelectric transducers used in current sonobuoys, it is suitable for active detection of underwater stealth targets, and its narrow pulse and high repetition characteristics are also suitable for underwater acoustic measurement.

Description

A plasma sonobuoy

technical field

The invention belongs to the technical field of underwater detection, and in particular relates to a plasma sonar buoy.

Background technique

Sonobuoy is an underwater acoustic remote sensing detector. It forms a buoy sonar system with buoy signal receiving and processing equipment, which can be used for underwater noise measurement, underwater temperature depth measurement, underwater channel measurement, underwater target detection and underwater Download newsletter etc. At present, according to the working method, sonobuoys can be divided into two types: active type and passive type. Among them, passive sonobuoys only receive signals and have no underwater acoustic signal transmitters; active sonobuoys mostly use a single cylindrical piezoelectric transducer shared by transceivers, which can measure distances while detecting targets, and their working frequency bands are generally In the range of 9 ~ 13kHz, the emitted sound wave waveform is a pulse waveform. At present, with the gradual improvement of the stealth performance of underwater targets, especially the anechoic covering has a good sound absorption effect on the medium and high frequency bands, the detection distance of conventional active and passive sonobuoys is gradually reduced, which requires the sonobuoy The detection frequency develops towards the low frequency.

Plasma sound source is a new type of underwater pulse sound source. Compared with piezoelectric transducers, it has higher energy efficiency, and has the characteristics of narrow pulse, wide frequency bandwidth, and high source level. Its working principle is also very different from the piezoelectric transducer, which belongs to the explosive sound source. The technical principle of plasma sound source is the mechanical effect of high-voltage pulse discharge in water, also known as "hydraulic effect". According to its discharge form, high-voltage pulse discharge in water can be divided into pulse arc discharge in water and pulse corona discharge in water.

Texas Tech University Austin has been working on the research and development of underwater pulsed arc discharge technology and related sound source products for nearly 20 years. Phoenix Science and Technology Corporation of the United States has also developed a plasma sound source based on pulsed arc discharge in water and applied it to sonobuoys. The sonobuoy can only discharge 20 times after each charge, and the acoustic signal generated has multiple oscillations. This oscillation is caused by bubble pulsation. Bubble pulsation has great randomness, which makes the repeatability of the acoustic signal worse, which is not conducive to the application of target detection and underwater acoustic measurement.

Contents of the invention

Aiming at the above-mentioned technical problems existing in the prior art, the present invention provides a plasma sonobuoy, which adopts a modular design to optimize the electromagnetic environment, avoids the electromagnetic interference of the high-voltage pulse discharge on the low-voltage module, and outputs pulsed sound waves without multiple Oscillation, good signal repeatability.

A plasma sonobuoy, comprising a low-voltage module and a high-voltage module connected thereto;

The low voltage module includes:

a positioning unit, configured to receive positioning information provided by satellites;

The communication unit is used to communicate with the external upper control system, receive the control signal sent by it, and send the positioning information to it;

The energy storage unit is used to store direct current and supply power to the positioning unit, communication unit and high voltage module;

The high voltage module includes:

A DC-DC conversion unit, configured to increase the voltage level of the direct current and output high-voltage direct current;

The pulse discharge unit is used to use the high-voltage direct current to regularly perform pulse discharge independently or according to the control signal.

The low-voltage module is connected to the high-voltage module through a connector or a cable, the two can be separated, and the low-voltage module can be recharged and used; the cable is preferably used, and the length can be adjusted, and the high-voltage module can be sunk to different depths according to needs. This adjusts the working frequency band of the sonar; the connector can be an electrical connector or a photoelectric composite connector, and the cable can be a waterproof cable or a photoelectric composite cable.

The energy storage unit can be a supercapacitor, a lithium battery or a photovoltaic battery; preferably a lithium battery, which has a high energy storage density and a long working time.

The DC-DC conversion unit is composed of a full-bridge inverter, an LC resonant circuit, a step-up transformer and a full-bridge rectifier connected in sequence.

The pulse discharge unit includes a current-limiting inductance, a high-voltage pulse capacitor, a freewheeling diode, a discharge switch, a trigger and a discharge electrode; wherein, one end of the current-limiting inductance is connected to the high voltage of the DC-DC conversion unit The other end of the current-limiting inductor is connected to one end of the high-voltage pulse capacitor, one end of the freewheeling diode is connected to one end of the discharge switch, the other end of the discharge switch is connected to the discharge electrode, and the other end of the high-voltage pulse capacitor is connected to the freewheeling diode. The other end is connected to the low-voltage output end of the DC-DC conversion unit and grounded, and the trigger pole of the discharge switch is connected to a trigger, and the trigger triggers the discharge switch at regular intervals or according to the control signal.

The high-voltage pulse capacitor can be an oil-immersed capacitor or a dry capacitor, and the discharge switch can be a semiconductor switch.

The discharge electrode is composed of an insulating medium and at least one metal electrode; the metal electrode is embedded in the insulating medium, one end of the metal electrode is exposed and is a discharge tip, and the other end is connected to the other end of the discharge switch; if There are multiple metal electrodes, and the other ends of all the metal electrodes are connected in parallel to the other end of the discharge switch.

The discharge electrode is a single electrode or a multi-electrode, a single electrode includes only one metal electrode, and a multi-electrode includes a plurality of metal electrodes. The insulating medium can be made of polyethylene, epoxy resin or tetrafluoro material.

The present invention has two working modes, one is an autonomous working mode, and the other is a passive working mode. The autonomous working mode is as follows: the low-voltage DC source in the energy storage unit charges the high-voltage pulse capacitor through the DC-DC conversion unit. The trigger signal is output, and after the discharge switch is triggered and turned on, the high-voltage pulse capacitor generates pulse plasma discharge into the water through the discharge electrode, and the discharge process causes plasma bubbles to pulsate, thereby generating pulse sound waves. When the trigger triggers the discharge switch, the positioning unit receives the positioning signal and sends the positioning information of the buoy to the upper control system (the control system on the mother ship or the mother machine) through the communication unit at regular intervals; after the discharge is completed, the DC-DC conversion unit restarts work, the energy storage unit starts to charge the high-voltage pulse capacitor again, and so on. The difference between the passive working mode and the autonomous working mode is that the triggering of the discharge switch is passive, and the trigger control signal is sent by the external upper control system, which is transmitted to the trigger of the discharge switch through the communication unit to trigger it.

Compared with this, the present invention adopts the pulsed plasma corona discharge technology in water. Compared with the pulsed arc discharge in water, there are two main technical differences. First of all, the discharge switch used by the former is a semiconductor composite switch, not a spark gap switch, and the switch life is much longer than that of the latter; secondly, the discharge electrode is a unipolar single electrode or multi-electrode structure, not a bipolar electrode pair structure , and the discharge is only carried out at the tip of the electrode, and there is no conduction arc between the high and low voltage electrode pairs. The main features of pulsed corona discharge technology in water are long life, good stability of sound source, no multiple oscillations of pulsed sound waves, high repeatability, high source level, wide frequency band, and its main working frequency band is adjustable from hundreds of Hz to Thousands of Hz, which is lower than the frequency of piezoelectric transducers used in current sonobuoys, is suitable for active detection of underwater stealth targets, and its narrow pulse and high repetition characteristics are also suitable for underwater acoustic measurements.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the sonobuoy of the present invention.

Fig. 2 is a schematic structural diagram of a high-voltage module under negative polarity output.

Fig. 3 is a schematic structural diagram of a high-voltage module under positive polarity output.

Fig. 4 is an acoustic pulse waveform diagram of the sonobuoy of the present invention.

Fig. 5 is a waveform diagram of an acoustic pulse of an existing sonobuoy.

Detailed ways

In order to describe the present invention more specifically, the technical solutions and working principles of the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1, a plasma sonar buoy includes a low-pressure module and a high-voltage module connected to it. Both modules are placed in a cylindrical container with a diameter of 20 cm. The cylindrical container of the low-pressure module is made of high-strength plastic. , the length is about 35cm, while the cylindrical vessel of the high voltage module is made of stainless steel for grounding, and the length is about 45cm.

The low-voltage module includes a positioning unit, communication unit and energy storage unit, and the high-voltage module includes a DC-DC conversion unit and a pulse discharge unit. The two modules are connected by a photoelectric composite connector, which has two-core electrical connection and two-core optical connection, and the two-core electrical connection is the connection between the energy storage unit and the DC-DC conversion unit, which requires low voltage and high current, and the two-core optical connection Connect the communication unit with the pulse discharge unit.

The low-voltage module can be removed for charging and reused, and each full charge can perform about 200 pulsed plasma discharges. In the low-voltage module, the positioning unit is used to receive the positioning information provided by the satellite; in this embodiment, it adopts a commercial GPS module, equipped with a satellite receiving antenna, and the positioning accuracy is less than 2m.

The communication unit is used to communicate with the external upper control system, receive the control signal sent by it, and send positioning information to it; in this embodiment, the communication unit adopts NRF905 single-chip wireless transceiver, and communicates with the control system on the mother ship through the transceiver antenna Communication, working in three ISM channels of 433/868/915MHz, the transceiver also contains a photoelectric module, which communicates with the trigger fiber of the semiconductor switch in the pulse discharge unit through the fiber optic interface of the photoelectric composite connector. The GPS satellite receiving antenna of the positioning unit and the communication transmitting and receiving antenna of the communication unit are all arranged on the top of the low-voltage module container and exposed on the water surface.

The energy storage unit is used to store direct current and supply power to the positioning unit, communication unit and high-voltage module; in this embodiment, it includes two lithium battery packs, one of which is 3V, and the 800mAh lithium battery pack supplies power to the positioning unit and communication unit. The other part uses a 12V, 2500mAh lithium battery pack to supply power to the high-voltage module, and its output is connected to the DC-DC conversion unit in the high-voltage module through the cable interface in the photoelectric composite connector; both lithium battery packs are equipped with charging adapters , can be recharged and used repeatedly.

In the high-voltage module, the DC-DC conversion unit is used to raise the voltage level of the direct current stored in the energy storage unit and output high-voltage direct current; in this embodiment, the DC-DC conversion unit consists of a full-bridge inverter, an LC resonant circuit, and a A step-up transformer and a full-bridge rectifier are connected in sequence; for negative polarity output, its circuit structure is shown in Figure 2; for positive polarity output, its circuit structure is shown in Figure 3. Among them, the full-bridge inverter uses IGBT as the switching device, the operating frequency is 100kHz, and its maximum operating current is 250mA. The value of L in the LC resonant circuit is 20μH, and the value of C is 120nF. The step-up transformer adopts a hollow coaxial transformer. 1:200, the maximum output voltage is 2400V, and the maximum output current is 1.25mA.

The pulse discharge unit is used to use high-voltage direct current to perform pulse discharge independently or according to the control signal; the pulse discharge unit includes a current-limiting inductor, a high-voltage pulse capacitor, a freewheeling diode, a semiconductor switch, a trigger and a Composition of discharge electrodes; as shown in Figure 2 for negative polarity output, one end of the current-limiting inductor is connected to the high-voltage output end of the DC-DC conversion unit, the other end of the current-limiting inductor is connected to one end of the high-voltage pulse capacitor, and the anode of the freewheeling diode It is connected to the cathode of the semiconductor switch, the anode of the semiconductor switch is connected to the discharge electrode through the output cable, and the other end of the high-voltage pulse capacitor is connected to the cathode of the freewheeling diode, the low-voltage output terminal of the DC-DC conversion unit and the container shell of the high-voltage module. ground, the gate of the semiconductor switch is connected to the flip-flop. For the positive polarity output as shown in Figure 3, one end of the current-limiting inductor is connected to the high-voltage output end of the DC-DC conversion unit, and the other end of the current-limiting inductor is connected to one end of the high-voltage pulse capacitor, the cathode of the freewheeling diode and the semiconductor switch. The anode is connected, the cathode of the semiconductor switch is connected to the discharge electrode through the output cable, the other end of the high-voltage pulse capacitor is connected to the anode of the freewheeling diode, the low-voltage output terminal of the DC-DC conversion unit, and the container shell of the high-voltage module and grounded. The gate is connected to the flip-flop.

In this embodiment, the current-limiting inductance is 100 μH, and the high-voltage pulse capacitor is a CBB solid capacitor encapsulated in epoxy resin, with a capacitance of 18 μF, a withstand voltage of 4000V, and an operating voltage of 2400V, so the energy of one discharge is 50J. The semiconductor switch is a module packaged together with a thyristor and a freewheeling diode, with a withstand voltage of 3600V and an operating voltage of 2400V.

The trigger of the semiconductor switch is connected with the optical fiber interface of the photoelectric composite connector to receive the control signal sent by the upper system; A series of pulse transformers. The trigger has two working modes: in the autonomous mode, the thyristor is automatically triggered at regular intervals; in the passive mode, it is connected to the communication unit of the low-voltage module through the connector, and the control signal provided by the control system on the mother ship is converted by the trigger signal Then trigger the SCR.

In this embodiment, the discharge electrode adopts a single electrode, which is composed of an insulating medium and a metal electrode; the metal electrode is embedded in the insulating medium, one end of the metal electrode is exposed and is a discharge tip, and the other end is connected to a semiconductor switch; the metal electrode adopts a single core Copper electrode, the electrode diameter is 0.5mm, the insulating medium is epoxy resin, the discharge tip is in contact with the water body, and the connection between the metal electrode and the semiconductor switch is vulcanized and sealed.

In this embodiment, the energy storage unit adopts a lithium battery pack, and the lithium battery pack outputs 12V low-voltage direct current, which is converted into high-frequency alternating current by IGBT, and then input into a step-up transformer after LC resonance, and after boosting, it is rectified by a full bridge to become high-voltage direct current. , charge the high-voltage pulse capacitor through the current-limiting inductor. When the thyristor is turned on, the energy stored in the high-voltage pulse capacitor is injected into the tip of the discharge electrode, generating plasma bubbles, and radiating pulse strong sound waves, as shown in Figure 4, which uses a hydrophone with a sensitivity of -210dB Measured by the instrument, the test distance is 3m, and the source level is converted to about 215dB.

Fig. 5 is the acoustic pulse waveform diagram of the sonobuoy developed by Phoenix Science and Technology Corporation of the United States. From the comparison of Fig. 4 and Fig. 5, it can be seen that the pulsed sound wave in this embodiment is a single pulse, and there is no pulsed arc discharge to generate multiple oscillating waves, so the repeatability Good, suitable for underwater acoustic measurement and detection of underwater stealth targets.

Claims (1)

1. A plasma sonobuoy, characterized in that: comprising a low voltage module and a high voltage module connected thereto; The low voltage module includes: a positioning unit, configured to receive positioning information provided by satellites; The communication unit is used to communicate with the external upper control system, receive the control signal sent by it, and send the positioning information to it; The energy storage unit is used to store direct current and supply power to the positioning unit, communication unit and high voltage module; The high voltage module includes: A DC-DC conversion unit, configured to increase the voltage level of the direct current and output high-voltage direct current; The pulse discharge unit is used to use the high-voltage direct current to perform pulse discharge at regular intervals independently or according to the control signal; The low-voltage module is connected to the high-voltage module through a photoelectric composite connector. The photoelectric composite connector has two-core electrical connections and two-core optical connections, wherein the two-core electrical connections are connected to the energy storage unit and the DC-DC conversion unit. The two-core optical connection is the connection between the communication unit and the pulse discharge unit; The energy storage unit adopts a lithium battery pack; the communication unit adopts an NRF905 single-chip wireless transceiver; the DC-DC conversion unit consists of a full-bridge inverter, an LC resonant circuit, a step-up transformer and A full-bridge rectifier is sequentially connected to form; The pulse discharge unit includes a current-limiting inductor, a high-voltage pulse capacitor, a freewheeling diode, a semiconductor switch, a trigger, and a discharge electrode; wherein, one end of the current-limiting inductor is connected to the high voltage of the DC-DC conversion unit. The other end of the current-limiting inductor is connected to one end of the high-voltage pulse capacitor, one end of the freewheeling diode is connected to one end of the semiconductor switch, the other end of the semiconductor switch is connected to the discharge electrode, and the other end of the high-voltage pulse capacitor is connected to the freewheeling diode. The other end is connected to the low-voltage output terminal of the DC-DC conversion unit and grounded, and the trigger pole of the semiconductor switch is connected to a trigger, and the trigger triggers the semiconductor switch at regular intervals or triggers the semiconductor switch according to the control signal; The discharge electrode is composed of an insulating medium and at least one metal electrode; the metal electrode is embedded in the insulating medium, one end of the metal electrode is exposed and is a discharge tip, and the other end is connected to the other end of the semiconductor switch; if There are multiple metal electrodes, and the other ends of all the metal electrodes are connected in parallel to the other end of the semiconductor switch.