CN113866835B - Electromagnetic emission system combining time domain three waveforms and control method - Google Patents
Electromagnetic emission system combining time domain three waveforms and control method Download PDFInfo
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Abstract
The invention relates to an electromagnetic emission system combining time domain three waveforms and a control method thereof, which aim to generate trapezoidal waves and triangular waves with different turn-off times, half sine waves with different pulse widths and emission currents of the combined waveforms. The transmitting system is composed of a main control circuit, a transmitting bridge circuit, an RLC series resonant circuit, a passive clamping circuit, a transmitting coil and the like. Setting emission parameters according to exploration requirements, and outputting PWM signals by a main control circuit to drive corresponding switch modules in an emission system through an optocoupler; when the transmitting bridge circuit is switched on, the passive clamping circuit provides different clamping voltages for the transmitting coil during the period of switching off of the trapezoidal wave or the triangular wave so as to realize controllable current switching-off time; when the RLC series resonant circuit is on, the storage capacitor powers the resonant circuit, producing a bipolar half sine wave. The electromagnetic emission system combining the time domain three waveforms is applied to induction-polarization double-field detection based on the SQUID, so that the problems of shallow detection blind areas and SQUID lock losing can be solved, and the overall exploration precision of the transient electromagnetic method is improved.
Description
Technical Field
The invention relates to an electromagnetic emission system and a control method for time domain three-waveform combination, which are suitable for the field of geophysical exploration or geological structure detection by an electromagnetic method, and particularly provide an excitation source for a magnetic source time domain electromagnetic detection method.
Background
The magnetic source time domain electromagnetic detection method utilizes a non-grounding loop to emit bipolar pulse current to the underground, the pulse current can be square wave, trapezoidal wave, triangular wave, half sine wave and the like, in the intermittent process of a primary field generated by emitted pulse, a receiving coil or a superconducting quantum interference device (SQUID, superconducting Quantum Interference Device) and a receiver collect signals of the secondary field changing along with time, and the data are processed and interpreted to obtain abundant resistivity or polarizability information of an underground medium. The transient electromagnetic method has the advantages of large detection depth, economy and convenience, and has been widely applied to geological resource exploration and engineering detection.
The traditional time domain electromagnetic method can only excite and interpret electromagnetic induction signals due to the limitation of a detecting instrument and a data interpretation method, the measuring parameters and interpretation parameters are single, the accuracy of data interpretation is low, and the accuracy of exploration results is low; because the transmitting coil is an inductive load and contains larger parasitic inductance, the current cannot be immediately reduced to zero after the transmitting current is cut off, but is attenuated in an e exponential manner, and overshoot and oscillation phenomena are also generated at the tail of the current, so that the waveform quality of the transmitting current is lower due to the reasons, shallow information is seriously lost, and the primary field cannot be counteracted and corrected during data interpretation; the low performance of the transmitting system and the single interpretation parameters severely limit the further development and application of the transient electromagnetic method.
In order to meet the requirement of simultaneous detection of deep and shallow layers, the traditional bipolar trapezoidal wave is not applicable any more, the bipolar triangular wave has rich high-frequency components and smaller pulse width, the propagation distance of electromagnetic waves is smaller, and at the moment, the signals obtained by the receiving system are mainly signals of the shallow layer geologic body; the pulse width of the half sine wave emission current is large, the low-frequency components are rich, and the half sine wave emission current can be used as an excitation source for deep geological body detection; the triangular wave and half sine wave combined emission current can realize detection of geologic bodies with different depths, and detection dead zones of an electromagnetic method are reduced.
The dual-parameter combined detection is an effective method for improving the detection precision of the TEM, the induced polarization effect is a common phenomenon existing in the earth, and in recent years, with the progress of instruments and the development of electromagnetic theory, researchers have conducted intensive research on the induced polarization effect, and meanwhile, the explanation precision of the induced field and the induced polarization signal can be effectively improved. The induction field (TEM) is a secondary induction magnetic field generated by the underground medium, and the induction field is interpreted to obtain the conductivity parameter of the underground medium; the polarization field (IP) is an induced polarization field generated by excitation after the earth is electrified, and the polarization field is interpreted to obtain the polarization rate parameter of the underground medium. The research finds that TEM and IP can detect water resources and metal ores, and in the low-frequency time domain electromagnetic detection process, the induction field and the polarization field are found to exist simultaneously; the induction field is fast attenuated in the early stage after the current is cut off, which is shown by coexistence of the induction field and the polarization field, mainly the induction field and the polarization field in the later stage. When the amplitude of the emission current is fixed, the shorter the turn-off time is, the shorter the polarization charging time is, so that the induced polarization field is weaker, and the method is suitable for induction field measurement; the longer the turn-off time, the longer the polarization charging time, resulting in stronger induced polarization field, suitable for polarization field measurement. Therefore, the combined emission current of the trapezoidal wave and the triangular wave which emit a plurality of different turn-off times can be used for simultaneously detecting the IP and TEM signals.
Superconducting quantum interferometers (SQUIDs, superconducting Quantum Interference Device) have the characteristics of low noise, large bandwidth and high sensitivity (of the order of fT), and have been successfully used in transient electromagnetism, since the polarized field signals are very weak and are difficult to obtain with conventional receiving coils, SQUIDs are ideal sensors for receiving induced-polarized field signals. However, SQUID sensors need to operate in low electromagnetic noise environments, and their system slew rate (2.4 mT/s) is also small, placing new demands on the transmitting system. The overshoot of the emission current and the oscillation of the tail can generate larger electromagnetic interference, which can cause the loss of lock of the SQUID system and can not work normally, so that an absorption circuit is needed to be connected in the turn-off process of the emission current to restrain the overshoot of the current and the oscillation of the tail. When the current magnitude of the emission current rises or falls too quickly, the SQUID system is out of lock due to exceeding the slew rate, the effect is still limited although the low-voltage clamping circuit can prolong the turn-off time of the emission current, the clamping circuit cannot change the emission current rising process, the SQUID system is unstable in operation, and the out-of-lock phenomenon still occurs. Therefore, the RLC series resonant circuit is added in the transmitting system, the generated bipolar half sine wave transmitting current has larger pulse width, the waveform ascending part and the waveform descending part are symmetrical, the overall change of the transmitting current is slower, the requirement of the SQUID system can be completely met, the SQUID system is prevented from losing lock, and the SQUID system can work stably. In order to combine with the advantage of the linear turn-off of the trapezoidal wave, the emission current of the combination of the trapezoidal wave and the half sine wave is used for an excitation source for the detection of the SQUID system, so that the stability and the precision of the detection system can be obviously improved.
Chinese patent CN107017610B discloses a passive constant voltage clamp fast turn-off circuit for a transient electromagnetic transmitter, wherein TVS tubes are connected in series to two ends of a transmitting coil through electronic switches to provide passive clamp voltage for the coil; in addition, a variable damping matching absorption circuit is adopted to absorb the electric energy of reverse discharge of the coil. The clamp voltage adjustable circuit is matched with the absorption circuit, so that the rapid turn-off of the emission current is realized.
Chinese patent CN108227011a discloses a dual trapezoidal wave transmitting system with controllable falling edge and a control method, in which a switch module is connected in series with a group of high voltage transient suppression diodes or a group of low voltage transient suppression diodes during the turn-off period of the transmitting current to form a high voltage clamp or a low voltage clamp, so as to generate a group of trapezoidal wave transmitting currents with different turn-off times, realize simultaneous detection of dual parameters of resistivity and polarizability, and the experimental result proves the effectiveness of the clamp voltage on changing the turn-off time of the transmitting current.
The above-mentioned methods disclose methods for a passive clamp circuit to rapidly or slowly turn off the current in the transmitting coil, both of which are directed to the trapezoidal wave transmitting current turn-off time. However, for shallow detection by a transient electromagnetic method and induction-polarization field double-field measurement based on a SQUID sensor, the existing emission system almost cannot meet the requirements; and most transmitters can only transmit trapezoidal wave transmitting current, and the single transmitting current waveform causes that a transmitting system is difficult to excite a high-quality secondary field when facing to more complicated geological conditions. How to transmit the combined waveform and the emission current with high waveform quality in the time domain electromagnetic method detection, reduce the detection blind area and realize the accurate measurement of the induction-polarization field double fields is a technical problem which is urgently solved by the technicians in the field.
Disclosure of Invention
The invention provides an electromagnetic emission system with time domain three waveform combination and a control method, which aim to solve the problems of single emission current waveform, limited shallow layer detection and loss of lock of an induction-polarization field double field based on SQUID sensor measurement.
The embodiment of the invention provides an electromagnetic emission system and a control method for time domain three-waveform combination, wherein the electromagnetic emission system comprises an external power supply, a main control circuit, an emission bridge circuit, a passive clamping circuit, an absorption circuit and an RLC series resonant circuit; the external power supply supplies power to the transmitting bridge circuit and also charges the energy storage capacitor; the main control circuit is used as a control part of the transmitting system and controls the switch module to work so as to generate different types of transmitting current waveforms; the transmitting bridge circuit is an H bridge circuit formed by four switch modules, and is used for providing bipolar trapezoidal wave or triangular wave transmitting current for the transmitting coil; the passive clamp circuit is composed of five groups of switch modules and four groups of transient suppression diodes (TVS), and one group of transient suppression diodes are connected in series at two ends of a transmitting coil during the turn-off period of transmitting current to provide a clamp voltage for the transmitting coil; the absorption circuit consists of a group of switch modules and a power resistor and is used for absorbing electric energy of reverse discharge of emission current and inhibiting oscillation of the tail part of the current; the RLC series resonance circuit is composed of a transmitting coil, a nonpolar capacitor and an inductor, and generates bipolar half sine wave transmitting current under the action of an energy storage capacitor and a switch module.
Further, the main control circuit outputs multiple paths of PWM waves according to the set emission parameters and drives corresponding switch modules in the emission system through the optocouplers, so that the emission system can be controlled to independently output trapezoidal wave or triangular wave emission currents with controllable turn-off time and half sine wave emission currents with different pulse widths; the emission current of the combination of the trapezoidal wave and the triangular wave, the combination of the trapezoidal wave and the half sine wave, and the combination of the triangular wave and the half sine wave can also be output.
Further, the PWM wave output by the main control circuit of the transmitting bridge is switched on and off by four switch modules of the optocoupler driving bridge, and when the pulse width of the PWM wave is larger than the inherent rising time between the power supply and the transmitting coil, trapezoidal wave transmitting current with adjustable duty ratio and period can be generated; when the pulse width of the PWM wave is smaller than the inherent rising time, the triangular wave emission current with adjustable pulse width and period can be generated.
Furthermore, in order to meet the requirement of high-power emission, the switch modules in the transmitting bridge circuit, the clamping circuit, the absorption circuit and the RLC series resonant circuit generally adopt IGBT modules, MOSFET modules or other types of switch modules with high withstand voltage and high withstand current.
Further, the passive clamp circuit is composed of a group of main switch modules, four groups of switch modules and four groups of transient suppression diodes; the master switch module is controlled by a signal generated by the NOR gate logic circuit, so that the master switch module is closed during the transmitting period and is opened during the transmitting current off period; each group of transient suppression diodes consists of a plurality of transient suppression diodes with the same voltage value in parallel connection, the clamping voltages of the four groups of transient suppression diodes are distributed from low voltage to high voltage, the selectable range of the clamping voltages is generally 8.5V to 120V, the main control circuit controls one group of transient suppression diodes to be connected in series with two ends of a transmitting coil in the period of transmitting current turn-off, and the turn-off time of the transmitting current is controlled according to the difference of the clamping voltages.
Further, the absorption circuit is composed of a group of switch modules and a power resistor; the main control circuit controls the power resistor to be connected in series with two ends of the transmitting coil during the turn-off period of the transmitting current, and the resistance value of the power resistor is generally 200 to 500 times that of the transmitting coil; during the turn-off period of the transmitting current, when a group of transient suppression diodes are connected in, the current in the transmitting coil breaks down the transient suppression diodes first and forms a loop, and when the energy in the transmitting coil is insufficient to maintain the breakdown state of the transient suppression diodes, the power resistor is connected in and forms a loop with the transmitting coil so as to absorb the residual energy in the transmitting coil and suppress the overshoot and tail oscillation of the transmitting current; during the turn-off period of the transmitting current, when the transient suppression diode is not connected, the power resistor and the transmitting coil form a loop, so that energy in the transmitting coil can be quickly absorbed, and the turn-off time of the transmitting current is shortened.
Further, the RLC series resonance circuit is composed of a transmitting coil, a nonpolar capacitor and a magnetic ring inductor, wherein the resistor in the transmitting coil and the resistor in the inductor are used as resistors of the resonance circuit, the inductor in the transmitting coil and the magnetic ring inductor are used as inductors of the resonance circuit, and a plurality of high-withstand voltage nonpolar capacitors connected in parallel are used as capacitors of the resonance circuit; the external power supply charges the polar energy storage capacitors, the on-off of the switch module is controlled by the main control circuit, and the two energy storage capacitors respectively supply power to the RLC series resonant circuit to generate bipolar half sine wave emission current; the inductance and capacitance in the RLC series resonant circuit determine the pulse width of the half sine wave transmit current.
Compared with the prior art, the technical scheme provided by the embodiment of the invention has the following beneficial effects: the transmitting bridge circuit can transmit bipolar triangular waves or trapezoidal waves under the control of the main control circuit, transient suppression diodes with different clamping voltages are connected in series at two ends of the transmitting coil during the turn-off period of the transmitting current, the turn-off time of the transmitting current is controllable, overshoot and tail oscillation of the transmitting current are suppressed through the connection of the absorption circuit, and the waveform quality of the transmitting current is improved. The RLC series resonance circuit is adopted to emit bipolar half sine wave emission current, so that slow change of the emission current is realized, and the lock losing of the SQUID sensor is restrained. The combination of half sine wave and triangular wave emission current realizes the simultaneous detection of the geologic bodies with different depths; the combination of triangular waves and trapezoidal waves with different turn-off times transmits current to realize the simultaneous measurement of the induction-polarization field double fields; the trapezoidal wave and half sine wave combined emission current realizes the high-precision detection based on the SQUID sensor; and the detection blind area of the time domain electromagnetic method is reduced, and the working efficiency is improved.
Drawings
FIG. 1 is a circuit diagram of a high power transient electromagnetic multi-waveform transmission system and control method of the present invention;
FIG. 2 is a general block diagram of a transient electromagnetic multi-waveform transmission system of the present invention;
FIG. 3 is a diagram of a triangle wave and trapezoidal wave transmitting circuit with controllable turn-off time based on a transmitting bridge;
FIG. 4 is a diagram of a half sine wave transmit circuit based on an RLC series resonant circuit;
FIG. 5 is a graph of trapezoidal wave emission current waveforms and clamping voltages at different off times;
FIG. 6 is a graph of triangular wave emission current waveforms at different off times;
FIG. 7 is a graph of half sine wave emission current waveforms of different magnitudes and pulse widths;
FIG. 8 is a graph of three combined transmit current waveforms;
Detailed Description
The present invention will be described in further detail with reference to the following examples in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
Examples
Referring to fig. 1 and 2, the time domain three-waveform combined electromagnetic emission system mainly comprises a main control circuit, a key part, a liquid crystal display screen, a low-power supply, an optocoupler drive, an emission bridge circuit, a passive clamping circuit, an absorption circuit, an RLC series resonant circuit, a transient suppression diode, a power resistor, an energy storage capacitor, an emission coil, a high-power supply and a series of switch modules. The low-power supply supplies power to the main control circuit; the key part and the liquid crystal display screen are used as man-machine interaction parts for selecting and determining emission parameters; the optocoupler driving part outputs PWM waves to boost and flow the PWM waves, and is used for controlling the on-off of the switch module; the high-power supply provides energy for the transmitting coil and the energy storage capacitor; the transmitting bridge consists of four switch modules and is used for generating bipolar triangular wave or trapezoidal wave transmitting current on the transmitting coil; the passive clamping circuit and the transient suppression diode are connected in series at two ends of the transmitting coil, and the turn-off time of the transmitting current is changed by applying different clamping voltages to the transmitting coil; the absorption circuit and the power resistor are connected in series at two ends of the transmitting coil, and can be used for rapidly switching off the transmitting current and inhibiting current overshoot and tail oscillation; the RLC series resonant circuit and the storage capacitor are used to generate a bipolar half sine wave transmit current on the transmit coil.
The transmitting bridge comprises an H bridge circuit formed by switch modules Q1, Q2, Q3 and Q4, four switch modules are respectively positioned on an upper bridge arm and a lower bridge arm of the H bridge circuit, a transmitting coil is connected between the upper bridge arm and the lower bridge arm, and the transmitting coil is equivalent to a resistor r and an inductor L1; the switching modules Q1, Q2, Q3 and Q4 are opened and closed according to a certain period and pulse width under the control of the main control circuit, and when the pulse width is smaller than the inherent rising time between the power supply and the transmitting coil, the transmitting coil can generate bipolar triangular wave transmitting current; when the pulse width is larger than the inherent rising time between the power supply and the transmitting coil, the transmitting coil can generate bipolar trapezoidal wave transmitting current; to meet the requirement of high-power emission, the switch modules Q1, Q2, Q3, Q4 are IGBTs, MOSFETs or other types of switches with high withstand voltage and high current.
The passive clamp circuit consists of a group of main switches Q7 and Q8, four groups of switches Q9, Q10, Q11, Q12, Q13, Q14, Q15 and Q16 and four groups of transient suppression diodes TVS1, TVS2, TVS3 and TVS 4; the main switches Q7 and Q8 are controlled to be on-off by logic signals generated by the NOR gate, and are opened when the emission current starts to be turned off and closed when the emission current starts to rise; the four-component switch is controlled to be switched on and off by the main control circuit, and one of the four-component switch is always switched on or the four-component switch is switched off; the clamping voltages of TVS1, TVS2, TVS3 and TVS4 are distributed from low to high, and each group of transient suppression diodes is formed by connecting a plurality of TVSs with the same clamping voltage in parallel; when a group of switches are opened, a group of transient suppression diodes are connected in series across the transmitting coil during the period of transmitting current turn-off, generating clamping voltages and changing the turn-off time of the transmitting current.
The absorption circuit consists of a group of switches Q5 and Q6 and a power resistor R, the switches Q5 and Q6 are controlled to be on-off by the main control circuit, and are opened when the emission current is started to be turned off and closed when the emission current starts to rise; during the turn-off period of the emission current, the power resistor is connected in series with two ends of the emission coil, when a group of TVS is connected, the current in the emission coil breaks down the TVS tube and forms a loop with the TVS, at the moment, the power resistor is equivalent to an open circuit state, and when the emission current is reduced to a breakdown state that the TVS cannot be maintained, the emission coil and the power resistor form a loop, and the residual energy is released; when no TVS is connected during the turn-off period of the transmitting current, the transmitting coil directly forms a loop with the power resistor, and the current in the transmitting coil can be turned off rapidly because the resistance value of the power resistor is far greater than that of the transmitting coil.
The RLC series resonance circuit consists of energy storage capacitors C1 and C2, circuit switching switches Q17, Q18 and Q19, resonance control switches Q1 and Q2, current flow direction control diodes D1 and D2, a nonpolar capacitor C3, a magnetic ring inductor L2 and a transmitting coil; after the energy storage capacitors C1 and C2 acquire the energy of the power supply, the power is supplied to the resonant circuit; the circuit change-over switches Q17, Q18 and Q19 are controlled to be switched on and off by the main control circuit, when the Q17, Q18 and Q19 keep an on state, the transmitting system transmits bipolar half sine waves, and when the Q17, Q18 and Q19 keep an off state, the transmitting system transmits bipolar triangular waves or trapezoidal waves; the resonance control switches Q1 and Q2 are controlled to be switched on and off by a main control circuit, the energy storage capacitor is controlled to be switched on and off with the resonance circuit, and the polarity of half sine wave current is changed; the current flow direction control diodes D1 and D2 are used for restraining the reverse current of the RLC resonant circuit, and the resonant process is ended when the current is reduced to zero; the nonpolar capacitor C3, the magnetic ring inductor L2 and the transmitting coil are charged and discharged after the energy of the energy storage capacitor is acquired, and half sine wave transmitting current is generated.
Referring to fig. 3, the operation of the triangular wave and trapezoidal wave transmitting circuit with controllable turn-off time is divided into four stages, namely forward power supply, forward power supply stopping, reverse power supply and reverse power supply stopping.
(1) Forward power supply: the switches Q1 and Q4 are simultaneously opened, the current flow direction in the transmitting coil is E-D1-Q1-r-L1-Q4-D4, and when the transmitting current is increased from zero and reaches a stable value, the transmitting coil is a trapezoidal wave; when the emission current is increased from zero and then does not reach a stable value, the triangular wave is obtained.
(2) And stopping power supply in the forward direction: the switches Q1 and Q4 are simultaneously closed, at the moment, the switches Q5, Q6, Q7 and Q8 are opened, the switch of one group of TVS tubes is always kept in an open state, at the moment, one group of TVS tubes among TVS1, TVS2, TVS3 and TVS4 is immediately connected in series with the transmitting coil to generate a clamping voltage V, the power supply voltage is U, t is the moment after the starting of the turn-off, at the moment, the current in the transmitting coil meets the equation (1), and the turn-off time t d Equation (2) is satisfied and the falling edge slope S satisfies equation (3).
(3) Reverse power supply: the switches Q5, Q6, Q7 and Q8 are simultaneously closed, the switches Q2 and Q3 are simultaneously opened, and the current flow direction in the transmitting coil is E-D3-Q3-L1-r-Q2-D2, so that the current flow direction in the transmitting coil is changed.
(4) And (5) reversely stopping power supply: the switches Q2 and Q3 are closed at the same time, at the moment, the switches Q5, Q6, Q7 and Q8 are opened, a group of TVS tubes and a power resistor R are connected in series with the transmitting coil, and different clamping voltages determine different turn-off times; the power resistor suppresses current overshoot and tail oscillation.
Referring to fig. 4, the operation of the half sine wave transmitting circuit based on the RLC series resonant circuit is divided into two phases, positive half-cycle resonance and negative half-cycle resonance, respectively.
(1) Positive half-cycle resonance: the switch Q1 is opened, Q17, Q18 and Q19 of the switch switching circuit are kept in an open state, at the moment, the energy storage capacitor C1 supplies power to the resonant circuit, the current flow direction in the transmitting coil is C1-D1-Q1-r-L1-Q18-C3-L2-Q17-Q19, the half sine wave pulse width satisfies the equation (4), and generally, the switch Q1 is opened for a longer time than the half sine wave pulse width, so that after resonance is completed, the transmitting current is kept to be zero and stable under the action of the diode D1.
(2) Negative half-cycle resonance: the switch Q2 is opened, the switch Q1 is closed, the Q17, the Q18 and the Q19 of the switch switching circuit are kept in an open state, the energy storage capacitor C2 supplies power to the resonant circuit, the current flow direction in the transmitting coil is C2-Q17-L2-C3-Q18-L1-r-Q2-D2, the half sine wave transmitting current flow direction is changed, the opening duration of the switch Q2 is the same as the opening duration of the switch Q1, and after resonance is completed, the transmitting current is kept to be zero and stable under the action of the diode D2.
The combined emission current of the trapezoidal wave and the triangular wave is eight stages, namely, forward trapezoidal wave emission, forward stop emission, forward triangular wave emission, forward stop emission, reverse trapezoidal wave emission, reverse stop emission, reverse triangular wave emission and reverse stop emission; the combined emission current of the trapezoidal wave and the half sine wave is six stages, namely, forward trapezoidal wave emission, forward stop emission, positive half-period resonance, reverse trapezoidal wave emission, reverse stop emission and negative half-period resonance; the combined emission current of the triangular wave and the half sine wave is six stages, namely, forward triangular wave emission, forward stop emission, positive half-period resonance, reverse triangular wave emission, reverse stop emission and negative half-period resonance.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.
Claims (7)
1. A control method of an electromagnetic emission system based on time domain three waveform combination is characterized in that: the device comprises an external power supply, a main control circuit, a transmitting bridge circuit, a passive clamping circuit, an absorption circuit and an RLC series resonance circuit; the main control circuit outputs multipath PWM waves according to the set emission parameters, the PWM waves drive a switch module acting on an emission bridge circuit through an optical coupler to control the electromagnetic emission system to output trapezoidal waves and triangular waves, the PWM waves drive a switch module acting on an RLC series resonant circuit through the optical coupler to control the electromagnetic emission system to output half sine wave emission currents, the PWM waves drive the switch module acting on the emission bridge circuit and the RLC series resonant circuit through the optical coupler at the same time to control the electromagnetic emission system to output emission currents of the trapezoidal waves and the triangular waves, the trapezoidal waves and the half sine waves and the triangular waves and the half sine waves; the PWM wave is driven by an optocoupler to act on a switch module of the passive clamping circuit and the absorption circuit and is used for changing the turn-off time of the emission current and inhibiting tail oscillation; the external power supply supplies power to the transmitting bridge circuit and also charges the energy storage capacitor; the main control circuit is used as a control part of the transmitting system and controls the switch module to work so as to generate different types of transmitting current waveforms; the transmitting bridge circuit is an H bridge circuit formed by four switch modules, and provides bipolar trapezoidal wave and triangular wave transmitting current for the transmitting coil; the passive clamp circuit is composed of five groups of switch modules and four groups of transient suppression diodes (TVS), and one group of transient suppression diodes are connected in series at two ends of a transmitting coil during the turn-off period of transmitting current to provide a clamp voltage for the transmitting coil; the absorption circuit consists of a group of switch modules and a power resistor and is used for absorbing electric energy of reverse discharge of emission current and inhibiting oscillation of the tail part of the current; the RLC series resonance circuit consists of a transmitting coil, a nonpolar capacitor and a magnetic ring inductor, and generates bipolar half sine wave transmitting current under the action of an energy storage capacitor and a switch module;
the specific process of outputting the current waveform by the trapezoid wave and the triangular wave combination by the transmitting system comprises the following steps:
the main control circuit outputs four paths of PWM waves, the two paths of PWM waves act on the Q1 and Q4 switch modules of the left half bridge of the H bridge, and a positive half-cycle trapezoidal wave and a positive half-cycle triangular wave are generated in the process; the other two paths of PWM waves act on the Q2 and Q3 switch modules of the right half-bridge of the H bridge, and negative half-cycle trapezoidal waves and negative half-cycle triangular waves are generated in the process; the emission system outputs bipolar trapezoidal wave and triangular wave combined current waveform in a cyclic reciprocating mode;
the specific process of outputting the trapezoid wave and half sine wave combined current waveform by the transmitting system comprises the following steps:
the main control circuit outputs five paths of PWM waves, the two paths of PWM waves act on the Q1 and Q4 switch modules of the left half bridge of the H bridge, and positive half-cycle trapezoidal waves are generated in the process; one path of PWM wave acts on Q17, Q18 and Q19 switch modules of the RLC series resonant circuit, and one path of PWM wave acts on Q1 switch module of the H bridge circuit, and in the process, C1 discharges to generate half sine wave of positive half period; when two paths of PWM waves act on the Q2 and Q3 switch modules of the right half bridge of the H bridge, negative half-cycle trapezoidal waves are generated in the process; one path of PWM wave acts on Q17, Q18 and Q19 switch modules of the RLC series resonant circuit, and one path of PWM wave acts on Q2 switch modules of the H bridge circuit, and in the process, C2 discharges to generate a half sine wave with a negative half period; the emission system outputs bipolar trapezoidal wave and half sine wave combined current waveform in a cyclic reciprocating mode;
the specific process of the current waveform combining the triangular wave and the half sine wave output by the transmitting system is as follows:
the main control circuit outputs five paths of PWM waves, two paths of narrow-bandwidth PWM waves act on Q1 and Q4 switch modules of a left half bridge of the H bridge, and a positive half-cycle triangular wave is generated in the process; one path of PWM wave acts on Q17, Q18 and Q19 switch modules of the RLC series resonant circuit, and one path of PWM wave acts on Q1 switch module of the H bridge circuit, and in the process, C1 discharges to generate half sine wave of positive half period; when two paths of narrow bandwidth PWM waves act on the Q2 and Q3 switch modules of the right half bridge of the H bridge, negative half-period triangular waves are generated in the process; one path of PWM wave acts on Q17, Q18 and Q19 switch modules of the RLC series resonant circuit, and one path of PWM wave acts on Q2 switch modules of the H bridge circuit, and in the process, C2 discharges to generate a half sine wave with a negative half period; with this cyclic reciprocation, the transmitting system outputs a bipolar triangular wave and half sine wave combined current waveform.
2. The method for controlling an electromagnetic emission system based on time domain three waveform combinations as claimed in claim 1, wherein: the main control circuit outputs multiple paths of PWM waves according to the set emission parameters and drives corresponding switch modules in the emission system through the optocouplers to control the emission system to independently output trapezoidal wave and triangular wave emission currents with controllable turn-off time and half sine wave emission currents with different pulse widths; or the emission system is controlled to output emission currents of the combination of the trapezoidal wave and the triangular wave, the combination of the trapezoidal wave and the half sine wave and the combination of the triangular wave and the half sine wave.
3. The method for controlling an electromagnetic emission system based on time domain three waveform combinations as claimed in claim 1, wherein: the emitting bridge is connected and disconnected by four switch modules of the optocoupler driving bridge circuit through PWM waves output by the main control circuit, and when the pulse width of the PWM waves is larger than the inherent rising time between the power supply and the emitting coil, trapezoidal wave emitting currents with adjustable duty ratio and period are generated; when the pulse width of the PWM wave is smaller than the inherent rising time, a triangular wave emission current with adjustable pulse width and period is generated.
4. The method for controlling an electromagnetic emission system based on time domain three waveform combinations as claimed in claim 1, wherein: the switch modules in the transmitting bridge circuit, the clamping circuit, the absorbing circuit and the RLC series resonant circuit are suitable for the requirement of high-power transmission, and the IGBT module or the MOSFET module with high withstand voltage and high withstand current is required to be selected.
5. The method for controlling an electromagnetic emission system based on time domain three waveform combinations as claimed in claim 1, wherein: the passive clamp circuit consists of a group of main switch modules, four groups of switch modules and four groups of transient suppression diodes; the master switch module is controlled by a signal generated by the NOR gate logic circuit, so that the master switch module is closed during the transmitting period and is opened during the transmitting current off period; each group of transient suppression diodes consists of a plurality of transient suppression diodes with the same clamping voltage value in parallel connection, the clamping voltage of the four groups of transient suppression diodes is distributed from low voltage to high voltage, the clamping voltage range is 8.5V to 120V, the main control circuit controls one group of transient suppression diodes to be connected in series with two ends of a transmitting coil in the transmitting current turn-off period, and the turn-off time of the transmitting current is controlled according to the difference of the clamping voltage.
6. The method for controlling an electromagnetic emission system based on time domain three waveform combinations as claimed in claim 1, wherein: the absorption circuit consists of a group of switch modules and a power resistor; the main control circuit controls the power resistor to be connected in series with two ends of the transmitting coil during the turn-off period of the transmitting current, and the resistance value of the power resistor is 200 to 500 times of that of the transmitting coil; during the turn-off period of the transmitting current, when a group of transient suppression diodes are connected in, the current in the transmitting coil breaks down the transient suppression diodes first and forms a loop, and when the energy in the transmitting coil is insufficient to maintain the breakdown state of the transient suppression diodes, the power resistor is connected in and forms a loop with the transmitting coil so as to absorb the residual energy in the transmitting coil and suppress the overshoot and tail oscillation of the transmitting current; during the turn-off period of the transmitting current, when the transient suppression diode is not connected, the power resistor and the transmitting coil form a loop, so that energy in the transmitting coil can be quickly absorbed, and the turn-off time of the transmitting current is shortened.
7. The method for controlling an electromagnetic emission system based on time domain three waveform combinations as claimed in claim 1, wherein: the RLC series resonance circuit is composed of a transmitting coil, a nonpolar capacitor and a magnetic ring inductor, wherein the resistor in the transmitting coil and the resistor in the inductor are used as resistors of the resonance circuit, the inductor in the transmitting coil and the magnetic ring inductor are used as inductors of the resonance circuit, and a plurality of high-voltage-resistant nonpolar capacitors which are connected in parallel are used as capacitors of the resonance circuit; the external power supply charges the polar energy storage capacitors, the on-off of the switch module is controlled by the main control circuit, and the two energy storage capacitors respectively supply power to the RLC series resonant circuit to generate bipolar half sine wave emission current; the inductance and capacitance in the RLC series resonant circuit determine the pulse width of the half sine wave transmit current.
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4316242A (en) * | 1980-09-04 | 1982-02-16 | General Electric Company | Wide input range, transient-immune regulated flyback switching power supply |
| US5121314A (en) * | 1991-02-04 | 1992-06-09 | Maxwell Laboratories | Bi-mode high voltage resonant power supply and method |
| JP2000341946A (en) * | 1992-09-25 | 2000-12-08 | Murata Mfg Co Ltd | Operating method of resonance type power supply circuit for high voltage generation |
| CN104682763A (en) * | 2015-03-10 | 2015-06-03 | 中国科学院电子学研究所 | Method and device for high-speed off of energy-feedback constant-voltage clamp |
| CN207301137U (en) * | 2017-09-21 | 2018-05-01 | 吉林大学 | A kind of new transient electromagnetic method pulse current radiating circuit |
| CN111352164A (en) * | 2020-03-20 | 2020-06-30 | 吉林大学 | Transient electromagnetic detection system with large transmitting magnetic moment and short turn-off time |
| CN112578466A (en) * | 2020-12-08 | 2021-03-30 | 重庆璀陆探测技术有限公司 | Energy-feedback type constant-voltage double-clamping circuit of transient electromagnetic transmitter and control method thereof |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9285496B1 (en) * | 2012-10-22 | 2016-03-15 | White's Electronics, Inc. | Truncated half-sine methods for metal detectors |
| CN104407391B (en) * | 2014-12-05 | 2017-02-22 | 吉林大学 | Magnetic source non-modulation type transmitter and control method thereof |
| CN104953884A (en) * | 2015-07-14 | 2015-09-30 | 中国科学院电子学研究所 | Bipolar half-sine current generating device and method for full-ATEM (airborne transient electromagnetic system) |
| CN105743385B (en) * | 2016-04-26 | 2018-05-04 | 吉林大学 | A kind of Transient Electromagnetic Transmitter current waveform shaping circuit |
| CN106208734A (en) * | 2016-08-22 | 2016-12-07 | 中国科学院电子学研究所 | Transient electromagnetic exploration system transmitter |
| CN107979300B (en) * | 2016-10-19 | 2020-10-27 | 中国科学院电子学研究所 | Bipolar trapezoidal current large magnetic moment transmitter and current generation method thereof |
| CN107065020B (en) * | 2017-01-09 | 2019-09-06 | 重庆璀陆探测技术有限公司 | The more wave investigation systems of twin coil manifold type |
| CN107783196B (en) * | 2017-11-22 | 2023-08-29 | 中国地质大学（武汉） | Transient electromagnetic instrument transmitter |
| CN107991708A (en) * | 2018-01-29 | 2018-05-04 | 中国科学院电子学研究所 | A kind of bipolarity triangular wave transient electromagnetic emission system |
| CN108227011B (en) * | 2018-02-02 | 2023-07-07 | 吉林大学 | Double-trapezoidal wave transmitting system with controllable falling edge and control method |
| CN110515129A (en) * | 2019-08-08 | 2019-11-29 | 吉林大学 | Urban underground space multi-coil pull-type dipole electromagnetic exploration apparatus and method |
| CN111965713A (en) * | 2020-07-15 | 2020-11-20 | 中国地质大学（武汉） | Passive constant voltage clamping transient electromagnetic transmitting circuit |
-
2021
- 2021-11-10 CN CN202111325720.1A patent/CN113866835B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4316242A (en) * | 1980-09-04 | 1982-02-16 | General Electric Company | Wide input range, transient-immune regulated flyback switching power supply |
| US5121314A (en) * | 1991-02-04 | 1992-06-09 | Maxwell Laboratories | Bi-mode high voltage resonant power supply and method |
| JP2000341946A (en) * | 1992-09-25 | 2000-12-08 | Murata Mfg Co Ltd | Operating method of resonance type power supply circuit for high voltage generation |
| CN104682763A (en) * | 2015-03-10 | 2015-06-03 | 中国科学院电子学研究所 | Method and device for high-speed off of energy-feedback constant-voltage clamp |
| CN207301137U (en) * | 2017-09-21 | 2018-05-01 | 吉林大学 | A kind of new transient electromagnetic method pulse current radiating circuit |
| CN111352164A (en) * | 2020-03-20 | 2020-06-30 | 吉林大学 | Transient electromagnetic detection system with large transmitting magnetic moment and short turn-off time |
| CN112578466A (en) * | 2020-12-08 | 2021-03-30 | 重庆璀陆探测技术有限公司 | Energy-feedback type constant-voltage double-clamping circuit of transient electromagnetic transmitter and control method thereof |
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