CN102129088A - Ground detector transmitter - Google Patents

Abstract

The invention discloses a ground probe transmitter, which includes a power supply, a main control circuit, a digital-to-analog conversion circuit, a transmitting circuit and a monitoring circuit, wherein the main control circuit is a single-chip microcomputer, the monitoring circuit includes a sampling circuit, and the transmitting circuit includes a bridge circuit, The isolation circuit and the transmitting antenna circuit, the isolation circuit is connected to the main control circuit, and the digital-to-analog conversion circuit is connected to the main control circuit. It is characterized in that: a switch circuit is added to the transmission circuit, and the control terminal of the switch circuit is connected to the output terminal of the control circuit. , the input end of the control circuit is connected to the digital-to-analog conversion circuit, the input end of the switch circuit is connected to the output end of the bridge circuit, the output end of the switch circuit is connected to the sampling circuit, and an insulating barrier double polar transistors, in parallel with the original insulated gate bipolar transistors. The invention has the advantages of short shut-off time, large emission current, deep measurement depth, complete monitoring functions, high integration and light weight.

Description

Geometry Transmitter

technical field

The invention relates to transient electromagnetic detection technology, in particular to a ground penetrating instrument transmitter.

Background technique

Transient electromagnetic detection method is a kind of induction electromagnetic detection method. The principle of transient electromagnetic detection is: the transient electromagnetic wave is attenuated by different media in each stratum during the process of propagating underground, and different media have different attenuation values for transient electromagnetic waves of different frequencies. As long as the characteristic spectrum of the transient electromagnetic signal corresponding to different formation substances is extracted from the echo signal, different substances in the formation can be inverted.

Transient electromagnetic detection has been more and more widely used in environmental protection, hydrogeology and engineering geology, energy and mining exploration.

The stability of the amplitude of the transient electromagnetic wave emitted by the transient electromagnetic device and the standard of the waveform are directly related to the accuracy of the detection result, and the intensity of the emission also determines the depth of detection. The existing ground penetrating instrument transmitter consists of power supply, main control circuit, digital-to-analog conversion circuit, transmitting circuit, slave control circuit, monitoring circuit and wave synchronization signal circuit. circuit connection.

The main control circuit is a single-chip microcomputer (MCU), which is mainly used to control the transmitting circuit to generate a bipolar rectangular wave with a certain frequency, and at the same time monitor the duty cycle of the rectangular wave, the waveform voltage and current, and the state of the waveform through the monitoring module; in addition The main control circuit also exchanges data with the slave control circuit to realize human-computer interaction. The control of the transmitting circuit by the main control circuit is mainly to select different current values according to the depth of detection. The current value is determined by the operator through the key input and the length of the selected transmitting antenna.

The transmitter circuit is the core of the transmitter to improve the waveform. It is mainly driven by the synchronization with the receiver and the drive signal sent by the main control circuit. The full bridge circuit composed of 4 insulated gate bipolar transistors can be used to achieve bipolar rectangular waves. Output. The transmitting current generates electromagnetic waves through the transmitting coil and transmits them underground.

The slave control circuit uses a complex programmable logic device (CPLD) as the control chip, through which the operator can adjust the size of the transmission current and the length of the transmission antenna to achieve the best transmission waveform; the voltage of the battery, the size of the transmission current and The length of the antenna can be displayed in real time on the display screen in the display circuit.

The monitoring circuit mainly monitors the emission current and waveform, and is mainly composed of a waveform state monitoring circuit and a current size monitoring circuit. Since the depth of detection is proportional to the size of the emission current, it is necessary to monitor the emission current; monitoring the emission current has two functions: one is to realize over-current protection; During the process, the voltage of the battery will gradually decrease, and the emission current will also decrease accordingly. Accurately detecting the emission current at any time can ensure the correctness of the inversion results. In order to accurately detect the emission current at any time, a current monitoring circuit is connected to the monitoring circuit, which samples the emission current through the sampling circuit, and converts the collected current signal through the analog-to-digital conversion circuit, and the current conversion value is sent to the main control In the circuit, the processor compares the sampling value with the current program control value, and adjusts the current emitted by the transmitting circuit to reach the set value, so as to ensure the stability of the emitting current. In addition, when the current detection value exceeds the set overcurrent value, the main control circuit will turn off the transmitter circuit to protect the system. A display in the display circuit displays relevant parameters of the emission current.

In the prior art, a bipolar rectangular wave current of a certain frequency is mainly generated through a bridge circuit and a constant current source circuit, and the emitted bipolar rectangular wave current of a certain frequency is sent to the ground through a transmitting antenna to transmit electromagnetic waves. Since the transmitting coil in the transmitting antenna is an inductive load, the current in the inductor decreases exponentially at the moment the switch tube is turned off, so that the trailing edge of the transmitting current also decays exponentially, which affects early signal detection; in addition, for the use of batteries as power supplies During the use of the transmitter, the voltage of the battery will gradually decrease, and the transmission current will also decrease accordingly, which will affect the echo signal and hinder the correctness of the inversion results in the processing stage.

Contents of the invention

The object of the present invention is to provide a ground-penetrating instrument transmitter with short shut-off time, large emission current, deep measurement depth, complete monitoring functions, high integration and light weight in view of the deficiencies in the prior art.

The purpose of the present invention is achieved by the following technical solutions:

A ground probe transmitter, comprising a power supply, a main control circuit, a digital-to-analog conversion circuit, a transmitting circuit, a slave control circuit, a monitoring circuit and a wave synchronization signal circuit, wherein the main control circuit is a single-chip microcomputer, the monitoring circuit includes a sampling circuit, and a transmitting circuit It includes a bridge circuit, an isolation circuit and a transmitting antenna circuit. The isolation circuit is connected to the main control circuit, and the digital-to-analog conversion circuit is connected to the main control circuit. The difference from the prior art is:

A switch circuit is added in the transmitting circuit, the control terminal of the switch circuit is connected with the output terminal of the control circuit, the input terminal of the control circuit is connected with the digital-to-analog conversion circuit, the input terminal of the switch circuit is connected with the output terminal of the bridge circuit, and the switch circuit The output terminal of the bridge circuit is connected with the sampling circuit, and an insulated gate bipolar transistor is respectively added on each arm of the bridge circuit, and is connected in parallel with the original insulated gate bipolar transistor.

The switch circuit is mainly composed of insulated gate bipolar transistors, the collector of the insulated gate bipolar transistors is connected to the output end of the bridge circuit, the emitter of the insulated gate bipolar transistors is connected to the sampling circuit, and the insulated gate bipolar transistors The gate is connected to the output end of the control circuit, the emitter and collector of the insulated gate bipolar transistor are connected in series with an energy feedback buffer circuit, and the gate and emitter are connected in series with a switch protection circuit.

The energy feedback buffer circuit includes a resistor, a capacitor and a diode, and is composed of a resistor connected in parallel with a diode and connected in series with a capacitor.

The switch protection circuit includes two fast recovery diodes, which are composed of two fast recovery diodes connected in reverse series.

The number of insulated gate bipolar transistors added on each arm is two.

A duty ratio monitoring circuit is added to the monitoring circuit, the detection input end of the duty ratio monitoring circuit is connected to the sampling circuit, and the output end is connected to the main control circuit.

A waveform voltage monitoring circuit is added to the monitoring circuit, the detection input end of the waveform voltage monitoring circuit is connected to the sampling circuit, and the output end is connected to the main control circuit.

A power supply voltage monitoring circuit is added to the monitoring circuit, the detection input terminal of the power supply voltage monitoring circuit is connected to the power supply, and the output terminal is connected to the main control circuit.

The advantages of the present invention are:

1. The main control circuit generates a programmable power supply voltage according to the current value input by the operator to provide emission currents with different current intensities and frequencies. Different levels are selected according to different measurement depths to adapt to exploration at shallow, medium and deep depths; Since an insulated gate bipolar transistor is added to each arm of the bridge circuit, the maximum emission current can reach 200A, which is better than the current maximum current of 50A in similar products;

2. Since the insulated gate bipolar transistor is used to form a full bridge circuit as an electronic switch, and a fast recovery diode is connected to provide a release circuit for reactive power, the reactive energy stored in the load inductance is fed back to the DC side, thus improving the emission current In addition, the system also monitors parameters such as the voltage, current and duty cycle of the emission current in real time and feeds them back to the main control circuit for processing, so that the pulse waveform of the emission current tends to the standard rectangular wave, which greatly improves the inversion results. the accuracy;

3. Add a power supply voltage monitoring circuit, which can monitor the power supply voltage in real time, so as not to affect the stability of the emission current due to changes in the power supply voltage;

4. High integration, light weight, can also use small transmitting coils, and can be used for underground detection in piggyback type.

Description of drawings

Fig. 1 is the connection block diagram of the transmitting circuit of the embodiment;

Fig. 2 is the electrical principle diagram of embodiment bridge circuit and switch circuit;

Fig. 3 is a connection block diagram of the monitoring circuit of the embodiment.

Detailed ways

The content of the present invention will be described in detail below in conjunction with the accompanying drawings and embodiments, but the present invention is not limited thereto.

Example:

With reference to Fig. 1 Fig. 2, a kind of geodetic instrument transmitter comprises power supply 15, main control circuit 1, digital-to-analog conversion circuit 2, transmitting circuit 10 and monitoring circuit, wherein main control circuit 1 is a single-chip microcomputer, and monitoring circuit includes sampling circuit 7 , the transmitting circuit 10 includes a bridge circuit 5, an isolation circuit 4 and a transmitting antenna circuit 6, the isolation circuit 4 is connected to the main control circuit 1, and the digital-to-analog conversion circuit 2 is connected to the main control circuit 1,

A switch circuit 8 is added in the transmitting circuit 10, the control end of the switch circuit 8 is connected with the output end of the control circuit 3, the input end of the control circuit 3 is connected with the digital-to-analog conversion circuit 2, and the input end of the switch circuit 8 is connected with the bridge circuit 5. The output terminal is connected, the output terminal of the switch circuit 8 is connected with the sampling circuit 7, as shown in the circuit diagram of Figure 2, an insulated gate bipolar transistor is respectively added on each arm of the bridge circuit 5, and the original insulated gate bipolar transistor Q1 , Q2, Q3, and Q4 are connected in parallel, and the number of additional IGBTs on each arm is 2, and the additional IGBTs Q5 and Q6 are connected in parallel with the original IGBT Q1, and the additional insulation The gate bipolar transistors Q9, Q10 are connected in parallel with the original IGBT Q2, the additional IGBTs Q7, Q8 are connected in parallel with the original IGBT Q3, and the additional IGBTs Q11, Q12 is connected in parallel with the original IGBT Q4. The transmitting antenna 6 is connected to both ends of the output resistor R3 of the bridge circuit 5 , the diode D1 is connected to the power supply 15 , and the resistors R1 , R2 , R4 , R5 are the input terminals of the bridge circuit 5 and connected to the isolation circuit 4 .

Referring to Fig. 1 and Fig. 2, the switch circuit 8 is mainly composed of an IGBT Q13, the collector of the IGBT Q13 is connected to the output terminal of the bridge circuit 5, and the emitter of the IGBT Q13 is connected to the sampling circuit R11 is connected, the gate of the IGBT Q13 is connected to the output terminal resistor R8 of the control circuit 3, the emitter and the collector of the IGBT Q13 are connected in series with an energy feedback buffer circuit, and the gate and the emitter are connected in series with a switch Protection circuit 9. The control circuit 3 includes an operational amplifier U1 , resistors R7 , R8 , R9 , R10 and a capacitor C2 . The input resistor R7 of the control circuit 3 is connected to the main control circuit 1 through the digital-to-analog conversion circuit 2 .

The energy feedback buffer circuit includes a resistor R6, a capacitor C1 and a diode D2, and is composed of a resistor R6 connected in parallel with a diode D2 and connected in series with a capacitor C1.

The switch protection circuit 9 includes two fast recovery diodes D3 and D4, which are composed of two fast recovery diodes D3 and D4 connected in series in reverse polarity.

The control of the transmitting circuit 10 by the main control circuit 1 is mainly to select different current values according to the depth of detection. The current value is input by the operator through keys, and the length of the selected transmitting antenna 6 is processed to generate a program-controlled signal. The signal generates a reference voltage signal after passing through the digital-to-analog conversion circuit 2, and the opening degree of the switch tube of the IGBT Q13 is adjusted through the signal, so as to adjust the emission current.

Referring to FIG. 3 , the original waveform state monitoring circuit 11 in the monitoring circuit is connected to the transmitting circuit 10 and the main control circuit 1 , the current monitoring circuit 12 is connected to the sampling circuit 7 and the main control circuit 1 , and the sampling circuit 7 is connected to the transmitting circuit 10 .

A duty cycle monitoring circuit 14 is added to the monitoring circuit, the detection input end of the duty cycle monitoring circuit 14 is connected to the sampling circuit 7 , and the output end is connected to the main control circuit 1 .

A waveform voltage monitoring circuit 13 is added to the monitoring circuit, the detection input terminal of the waveform voltage monitoring circuit 13 is connected to the sampling circuit 7 , and the output terminal is connected to the main control circuit 1 .

The waveform voltage monitoring circuit 13 and the duty ratio monitoring circuit 14 are mainly to ensure that the voltage value of the transmitted pulse waveform is maintained within the range allowed by the transmitting circuit 10, and to ensure that the periodicity of the waveform transmission is synchronized with the signal acquisition of the receiver .

A power supply voltage monitoring circuit 16 is added to the monitoring circuit. The detection input terminal of the power supply voltage monitoring circuit 16 is connected to the power supply 15 , and the output terminal is connected to the main control circuit 1 . The power supply voltage monitoring circuit mainly converts the analog value of the power supply voltage into a digital value that can be processed by the processor, so as to realize the monitoring of the voltage.

In order to ensure the stability of the system, at first the stability of the power supply 15 supply will be guaranteed, so the voltage of the battery of the power supply 15 should be monitored in real time. Into the receiver, the power level of the transmitting device can be clearly seen at the receiving end, the power level is displayed on the receiver, and the other way is sent to the main control circuit for processing, and the power status of the battery is displayed in real time on the display screen of the display circuit for the operator to identify.

Claims (6)

1. visit ground instrument transmitter for one kind, comprise power supply, governor circuit, D/A converting circuit, radiating circuit and observation circuit, wherein governor circuit is a single-chip microcomputer, observation circuit comprises sample circuit, radiating circuit comprises bridge circuit, buffer circuit and emitting antenna circuit, buffer circuit is connected with governor circuit, and D/A converting circuit is connected with governor circuit, it is characterized in that:

Set up on-off circuit in the radiating circuit, the control end of described on-off circuit is connected with the output terminal of control circuit, the input end of control circuit is connected with D/A converting circuit, the input end of on-off circuit is connected with the output terminal of bridge circuit, the output terminal of on-off circuit is connected with sample circuit, set up igbt respectively on each arm of bridge circuit, in parallel with original igbt.

2. spy according to claim 1 ground instrument transmitter; it is characterized in that: described on-off circuit mainly is made up of igbt; the collector of igbt is connected with the output terminal of bridge circuit; the emitter of igbt is connected with sample circuit; the gate pole of igbt is connected with the output terminal of control circuit; the emitter of igbt and collector are in series with energy feedback buffer circuit, and gate pole and emitter are in series with the switch protection circuit.

3. spy according to claim 1 ground instrument transmitter, it is characterized in that: the quantity of the igbt of setting up respectively on described each arm is 2.

4. spy according to claim 1 ground instrument transmitter, it is characterized in that: set up the dutycycle observation circuit in the observation circuit, the detection input end of described dutycycle observation circuit is connected with sample circuit, and output terminal is connected with governor circuit.

5. spy according to claim 1 ground instrument transmitter, it is characterized in that: set up the waveform voltage observation circuit in the observation circuit, the detection input end of described waveform voltage observation circuit is connected with sample circuit, and output terminal is connected with governor circuit.

6. spy according to claim 1 ground instrument transmitter, it is characterized in that: set up supply voltage monitoring circuit in the observation circuit, the detection input end of described supply voltage monitoring circuit is connected with power supply, and output is connected with governor circuit through analog to digital conversion circuit.

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