Direct-current and low-frequency regulation dual-purpose current-stabilized power supply for observing seismic earth resistivity

Abstract

The invention relates to the related technical field of seismic observation, in particular to a dual-purpose current-stabilized power supply for direct current and low frequency regulation for seismic earth resistivity observation, which comprises an input rectification filter circuit, a high-frequency isolation and resonance circuit, a high-frequency DC / AC inverter circuit and a control module, the input rectification filter circuit is used for being connected with a power supply input end and used for rectifying and filtering input current. The high-frequency isolation and resonance circuit is used for transmitting and converting electric energy in a high-frequency alternating current mode and outputting direct current so as to improve the electric energy conversion efficiency and achieve safe electric isolation. The high-frequency DC / AC inverter circuit is connected with the output end of the secondary rectification circuit and is used for converting the direct current into alternating current and outputting the alternating current; and the control module is used for controlling a combined circuit consisting of the rectification filter circuit, the high-frequency isolation and resonance circuit and the high-frequency DC / AC inverter circuit, and carrying out direct-current power supply output or alternating-current power supply output based on the combined circuit.

Description

Technical Field

[0001] The present application relates to the technical field of earthquake ground resistivity observation, and particularly relates to a DC and low-frequency adjustable dual-purpose constant current power supply for earthquake ground resistivity observation. Background Art

[0002] Ground resistivity monitoring is an effective means of earthquake precursor monitoring. There are currently more than eighty ground resistivity monitoring stations in the earthquake network of our country. When these stations were initially built, the quality of the observed data was very good. However, with the rapid expansion of the urban rail transit network, the ground current generated by the operation of urban rail transit has caused significant electromagnetic interference to the observation stations around the city. These interference signals are mainly concentrated in the near DC frequency band, overlapping with the working frequency band of the existing observation system, resulting in limited anti-interference ability of the traditional DC observation system. Summary of the Invention

[0003] In view of this, a DC and low-frequency adjustable dual-purpose constant current power supply for ground resistivity observation in the present application is applied in ground resistivity observation to meet the application requirements of different stations and ensure the accuracy and quality of the observed data.

[0004] The present application provides a DC and low-frequency adjustable dual-purpose constant current power supply for earthquake ground resistivity observation, which is characterized by including: an input rectifier filter circuit, a high-frequency isolation and resonance circuit, a high-frequency DC / AC inverter circuit, and a control module;

[0005] The input rectifier filter circuit is used to connect to the power input terminal and rectify and filter the input current;

[0006] The high-frequency isolation and resonance circuit includes: a high-frequency link circuit, a high-frequency transformer circuit, and a secondary rectification circuit connected in sequence;

[0007] One end of the high-frequency link circuit is connected to the input rectifier filter circuit, and the other end is connected to the input terminal of the high-frequency transformer circuit;

[0008] The output terminal of the high-frequency transformer circuit is connected to the input terminal of the secondary rectification circuit;

[0009] The high-frequency isolation and resonance circuit is used to transmit and convert electrical energy in the form of high-frequency alternating current and output direct current to improve the electrical energy conversion efficiency and achieve safe electrical isolation;

[0010] The high-frequency DC / AC inverter circuit is connected to the output terminal of the secondary rectification circuit and is used to convert direct current into alternating current for output;

[0011] The control module is used to control the combined circuit composed of the rectification and filtering circuit, the high-frequency isolation and resonance circuit, and the high-frequency DC / AC inversion circuit, and perform DC power output or AC power output based on the combined circuit.

[0012] In some embodiments, the input rectification and filtering circuit is a Vienna rectification circuit.

[0013] In some embodiments, the high-frequency isolation and resonance circuit is an LLC circuit that controls energy transfer by adjusting the switching frequency.

[0014] In some embodiments, the high-frequency DC / AC inversion circuit and the control module adopt a single-phase full-bridge structure;

[0015] The control module is used to control the high-frequency DC / AC inversion circuit by means of sinusoidal pulse width modulation (SPWM).

[0016] In some embodiments, the control module includes: a centralized control circuit, a DCAC control circuit, a DCDC control circuit, a DC output control switch, a local display and control unit, and a host computer;

[0017] The DCAC control circuit, the DCDC control circuit, the DC output control switch, the local display and control unit, and the host computer are respectively connected to the centralized control circuit.

[0018] In some embodiments, the centralized control circuit, based on an ARM controller, coordinates and controls the relationship between DC output and AC output, as well as the host computer and local control; at the same time, it controls the DCDC output power to cooperate with AC and DC outputs;

[0019] The DCDC control circuit is used to control DC constant voltage and constant current output, accept instructions from the centralized control circuit, monitor and report the operating status of the DC power supply to the centralized control circuit;

[0020] The DCAC control circuit is used to control the AC output frequency and amplitude adjustment. A frequency-controllable square wave generated by the internal PWM controller of the ARM is used to control the output frequency; the output voltage is given by adjusting the analog quantity; the output voltage, current, and frequency status are collected and calculated through the internal integrated ADC of the ARM and uploaded to the display board in real time. At the same time, outer loop adjustment, fault detection, and protection control are realized;

[0021] The display and control unit is used for power supply body display and control functions; it obtains data from the centralized control circuit to realize the display of the output parameters and working status of the power supply.

[0022] In some embodiments, the centralized control circuit includes: a shutdown and desaturation circuit, a constant voltage closed-loop control circuit, a constant current closed-loop control circuit, and a current cutoff competition circuit.

[0023] In some embodiments, the centralized control circuit includes: a shutdown desaturation circuit, a constant voltage closed-loop control circuit, a constant current closed-loop control circuit, and a current cutoff competition circuit;

[0024] Among them, the constant voltage closed-loop control circuit and the constant current closed-loop control circuit are connected in parallel.

[0025] In some embodiments, the relay of the shutdown desaturation circuit is connected to the constant voltage control given port and the constant current control given port.

[0026] In some embodiments, the resistors in the constant voltage closed-loop control circuit and the constant current closed-loop control circuit are high-precision resistors; the operational amplifier in the constant current closed-loop control circuit is a high-precision operational amplifier.

[0027] A DC and low-frequency adjustable dual-mode constant current power supply for seismic georesistivity observation provided by the present application includes an input rectifier filter circuit, a high-frequency isolation and resonance circuit, a high-frequency DC / AC inverter circuit, and a control module; the input rectifier filter circuit is used to connect to the power input terminal and rectify and filter the input current; the high-frequency isolation and resonance circuit includes: a high-frequency link circuit, a high-frequency transformer circuit, and a secondary rectification circuit connected in sequence; one end of the high-frequency link circuit is connected to the input rectifier filter circuit, and the other end is connected to the input terminal of the high-frequency transformer circuit; the output terminal of the high-frequency transformer circuit is connected to the input terminal of the secondary rectification circuit; the high-frequency isolation and resonance circuit is used to transmit and convert electrical energy in the form of high-frequency alternating current and output direct current to improve the electrical energy conversion efficiency and achieve safe electrical isolation; the high-frequency DC / AC inverter circuit is connected to the output terminal of the secondary rectification circuit and is used to convert direct current into alternating current for output; the control module is used to control the combined circuit composed of the rectifier filter circuit, the high-frequency isolation and resonance circuit, and the high-frequency DC / AC inverter circuit, and perform DC power output or AC power output based on the combined circuit. With such a setting, the DC and AC dual-mode functions are realized, and the potential safety hazards caused by grounding at the output terminal are fully considered through the high-frequency isolation and resonance circuit. That is, in the solution provided by the present application, in view of the characteristics of DC and AC observations of georesistivity, a constant current power supply with DC and AC power supply functions is developed, which can set DC and AC power supplies according to requirements, cooperate with AC and DC georesistivity observation instruments to measure georesistivity, meet the requirements of different stations, obtain more reliable georesistivity data, and provide more accurate data support for earthquake prediction. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and other objects, features, and advantages of the present application will become more apparent by describing the embodiments of the present application in more detail with reference to the accompanying drawings. The drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present application and do not constitute a limitation to the present application. In the drawings, the same reference numerals generally represent the same components or steps.

[0029] Figure 1 It is a schematic circuit diagram of a DC and low-frequency adjustable dual-purpose constant current power supply for seismic geoelectric resistivity observation provided by an embodiment of the present application.

[0030] Figure 2 It is a schematic circuit diagram of an input rectifier filter circuit provided by an embodiment of the present application.

[0031] Figure 3 It is a schematic circuit diagram of a high-frequency isolation and resonance circuit provided by an embodiment of the present application.

[0032] Figure 4 It is a schematic diagram of a resonant converter provided by an embodiment of the present application.

[0033] Figure 5 It is a schematic circuit diagram of a high-frequency DC / AC inverter provided by an embodiment of the present application.

[0034] Figure 6 It is a schematic diagram of sinusoidal pulse width modulation provided by an embodiment of the present application.

[0035] Figure 7 It is a schematic circuit diagram of a control module provided by an embodiment of the present application.

[0036] Figure 8 It is a schematic circuit diagram of a centralized control circuit provided by an embodiment of the present application. Detailed implementation manners

[0037] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0038] Figure 1 It is a schematic flow diagram of a DC and low-frequency adjustable dual-purpose constant current power supply for seismic geoelectric resistivity observation provided by an embodiment of the present application. As Figure 1 shown, the DC and low-frequency adjustable dual-purpose constant current power supply for seismic geoelectric resistivity observation includes: an input rectifier filter circuit, a high-frequency isolation and resonance circuit, a high-frequency DC / AC inverter circuit, and a control module;

[0039] The input rectifier and filter circuit is used to connect to the power input terminal and rectify and filter the input current.

[0040] The high-frequency isolation and resonance circuit includes: a high-frequency link circuit, a high-frequency transformer circuit, and a secondary rectification circuit connected in sequence.

[0041] One end of the high-frequency link circuit is connected to the input rectifier and filter circuit, and the other end is connected to the input terminal of the high-frequency transformer circuit.

[0042] The output terminal of the high-frequency transformer circuit is connected to the input terminal of the secondary rectification circuit.

[0043] The high-frequency isolation and resonance circuit is used to transmit and convert electrical energy in the form of high-frequency alternating current and output direct current to improve the electrical energy conversion efficiency and achieve safe electrical isolation.

[0044] The high-frequency DC / AC inverter circuit is connected to the output terminal of the secondary rectification circuit and is used to convert direct current into alternating current for output.

[0045] The control module is used to control the combined circuit composed of the rectifier and filter circuit, the high-frequency isolation and resonance circuit, and the high-frequency DC / AC inverter circuit, and perform direct current power output or alternating current power output based on the combined circuit.

[0046] Specifically, in the solution provided by the present application, this power supply is a power supply using a high-frequency transformer for isolation. The specific implementation scheme is that Vienna rectification is adopted for the input, which has the advantages of high efficiency, low noise, high reliability, and small current harmonics. DCDC adopts high-frequency LLC resonance technology, which can effectively improve the power density of the switching power supply, and the high-frequency switch can greatly reduce the size of the isolation device. After isolation, a stable and reliable direct current will be obtained through the secondary rectification circuit. This direct current can be directly output as a DC constant current source in the DC mode, and can be used as a bus support for the subsequent inverter unit in the AC mode, and then inverted through a single-phase H-bridge inverter to obtain single-phase frequency-modulated alternating current.

[0047] Specifically, the input rectifier and filter circuit is a Vienna rectification circuit. Refer to Figure 2 , the input rectifier and filter circuit adopts a Vienna rectification PFC power factor correction circuit, which has technical characteristics such as high power factor and small input current harmonics, effectively suppresses power grid pollution, improves power quality, makes the input current waveform close to sinusoidal, has characteristics such as low total harmonic current and improved power factor.

[0048] In some embodiments, the high-frequency isolation and resonance circuit is an LLC circuit that controls energy transmission by adjusting the switching frequency. To ensure safety in use and in combination with the actual operating conditions of the product, the actual operating condition is that both poles of the power supply output are connected to the ground. Electrical isolation between the front and rear stages must be achieved. Therefore, DCDC adopts phase-shifted full-bridge resonance + high-frequency transformer isolation technology. Increasing the switching frequency can effectively reduce the size of the isolation transformer. However, when the switching frequency is increased, the switching loss will inevitably increase. The resonant converter can use soft switching to effectively reduce the switching loss and enable the system to operate at high frequencies. For the schematic diagram, refer to Figure 3 。

[0049] There are various different classification methods for resonant converters. According to the connection relationship between the load and the resonant circuit, resonant converters can be divided into series resonant converters, parallel resonant converters, and series-parallel resonant converters. The LLC we designed and used this time belongs to the series-parallel resonant converter. The structure of the resonant converter is as shown in Figure 4 shown. An AC square-wave voltage or current is applied across the resonant network to generate high-frequency resonance. After the resonant voltage or current is rectified and filtered, it is converted into a DC voltage or current, thereby achieving DC-DC conversion. Different from the traditional PWM (pulse width modulation) converter, LLC is a resonant circuit that achieves a constant output voltage by controlling the switching frequency (frequency regulation). The LLC resonant circuit consists of a switching network (half-bridge or full-bridge), a resonant capacitor (C), a resonant inductor (L), a transformer excitation inductor (L), a transformer, and a rectifier.

[0050] In some embodiments, the high-frequency DC / AC inverter circuit and the control module adopt a single-phase full-bridge structure; the control module is used to control the high-frequency DC / AC inverter circuit by means of sinusoidal pulse width modulation (SPWM).

[0051] Refer to Figure 5 、 Figure 6 . The inverter part adopts a single-phase full-bridge structure. The inverter selects a wide-bandgap semiconductor device SIC-MOSFET as the switching element. Compared with traditional IGBT devices, SIC-MOSFET has the characteristics of low switching loss and a high temperature tolerance range. The switching frequency can reach 100k, which can greatly reduce the output filtering parameters and ensure the waveform quality during output.

[0052] Taking advantage of its relatively high switching frequency, the inverter is controlled by means of sinusoidal pulse width modulation (SPWM) to convert a stable direct current into an alternating current with a pulse width modulated output. As shown in the figure, SPWM adopts a bipolar mode, that is: the upper and lower switching tube elements of the same bridge arm are complementary to each other for on and off, and the diagonal elements are turned on and off simultaneously. Therefore, the amplitude of the output SPWM wave is constant, and the width changes according to the sine law. The fundamental frequency of this alternating current is the required power supply output frequency. The pulse width modulated wave output by the inverter is filtered by an LC filter circuit to obtain a pure sine wave alternating current with very small harmonic components contained therein.

[0053] In some embodiments, referring to Figure 7 , the control module includes: a centralized control circuit, a DC-AC control circuit, a DC-DC control circuit, a DC output control switch, a local display and control unit, and a host computer;

[0054] The DC-AC control circuit, the DC-DC control circuit, the DC output control switch, the local display and control unit, and the host computer are respectively connected to the centralized control circuit.

[0055] Among them, the centralized control circuit is based on an ARM controller, and its main functions are to coordinate and control the relationship between DC output and AC output, as well as the host computer and local control. At the same time, it controls the DC-DC output power to cooperate with AC and DC outputs.

[0056] The DC-DC control circuit is mainly used for controlling DC constant voltage and constant current output control, accepting instructions from the centralized control circuit, monitoring and reporting the operating status of the DC power supply to the centralized control circuit;

[0057] The DC-AC control circuit controls output frequency and amplitude regulation, and is an outer loop control. The AC control board generates a square wave with a controllable frequency through the internal PWM controller of the ARM, thereby controlling the output frequency and adjusting the analog quantity setting to achieve the output voltage setting; it collects and calculates the output voltage, current, and frequency status through the internal ADC integrated in the ARM, and uploads them to the display board in real time through RS232. At the same time, it realizes outer loop regulation, fault detection, and protection control.

[0058] The display and control unit mainly realizes the display and control functions of the power supply body, obtains data from the centralized control circuit through RS232, and realizes the display of the output parameters and working status of the power supply. In the local control state, it can adjust the output voltage and frequency of the power supply, and control the start and stop of the power supply;

[0059] In some embodiments, referring to Figure 8 ; the centralized control circuit includes: a shutdown desaturation circuit, a constant voltage closed-loop control circuit, a constant current closed-loop control circuit, and a current cut-off competition circuit. The constant voltage closed-loop control circuit and the constant current closed-loop control circuit are in parallel.

[0060] The relay of the shutdown and desaturation circuit is connected to the constant voltage control given port and the constant current control given port. The resistors in the constant voltage closed-loop control circuit and the constant current closed-loop control circuit are high-precision resistors; the operational amplifier in the constant current closed-loop control circuit is a high-precision operational amplifier.

[0061] Specifically, this circuit consists of four parts: a shutdown and desaturation circuit, a constant voltage closed-loop control, a constant current closed-loop control, and a current cutoff competition, etc., which can achieve. During the startup process, the power supply decreases and the output overshoot is reduced. The functions of constant voltage and constant current real-time current limiting control.

[0062] In the figure, it consists of the relay KA9, the triode V6, -15V, and the PI-RUN signal of the single-chip microcomputer to form the shutdown and desaturation circuit.

[0063] In the shutdown state, PI-RUN is at a low level, and the voltage given GV-V-D and the current given signal GV-I-D signals are all switched to -15V. At this time, the constant voltage and constant current integral capacitors composed of C135, C136, and C147, C148 discharge. The cathode PI-RUN of VD41 and VD50 has a limit amplitude output of 0.7V. At this time, the given value to the drive circuit is less than 1V, and the regulator exits the saturation state.

[0064] During the power supply startup process, PI-RUN is at a high level, and the voltage given GV-V-D and the current given signal GV-I-D signals are all switched to the DA digital output given port. At this time, the constant voltage and constant current integral capacitors composed of C135, C136, and C147, C148 charge. The limit amplitude output of the cathode of VD41 and VD50 will gradually increase slowly from +0.7 according to the voltage and current feedback calculation, and the maximum value is -4.7V (the maximum saturation voltage). At this time, the power supply completes the soft startup process and operates according to the constant voltage or constant current state.

[0065] The voltage regulator consists of parts such as R198, R199, C135, C136, R202, A5, R203, VD41, etc. According to the voltage feedback VF and the given value GV-V-D, the voltage closed-loop control is completed. Among them, VD41 is a limiting zener diode to ensure that the power supply output will not exceed the maximum preset value.

[0066] The current regulator consists of parts such as R222, R223, C148, C147, R220, A5, R224, VD50, etc. According to the current feedback IF and the given value GV-I-D, the voltage-current loop control is completed. Among them, VD50 is a limiting zener diode to ensure that the power supply output will not exceed the maximum preset value.

[0067] A5C and VD45 are current clamping circuits. This circuit is connected in parallel with the output of the inner voltage loop to form a closed-loop voltage and current limiting circuit. When the given current is large and the given voltage is low, the current regulator saturates and outputs, and the current loop no longer plays a control role. The voltage closed-loop outputs the control power supply according to the control intention. According to the load operating state, when the voltage given is large and the current given is small, the level at XC9 is clamped and controlled by the current loop and is controlled by the voltage at pin 10 of the A5 operational amplifier. The power supply operates in the constant current control state.

[0068] Among them, in the figure, R198, R199, R202, R222, R224, and R225 are all high-precision resistors, and A5 is a high-precision operational amplifier. Combining high-precision voltage and current sampling together ensures the high-precision voltage and current output of the power supply.

[0069] The above description has been given for purposes of illustration and description. Additionally, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions, and sub-combinations thereof.

Claims

1. A DC and low-frequency regulated dual-purpose current-stabilized power supply for seismic ground resistivity observation, characterized in that: include: Input rectification and filtering circuit, high-frequency isolation and resonance circuit, high-frequency DC / AC inverter circuit and control module; The input rectifying and filtering circuit is used to connect to the power input terminal and to rectify and filter the input current; The high-frequency isolation and resonance circuit comprises: a high-frequency link circuit, a high-frequency transformer circuit and a secondary rectification circuit connected in sequence; One end of the high-frequency link circuit is connected to the input rectifier filter circuit, and the other end is connected to the input end of the high-frequency transformer circuit; The output end of the high-frequency transformer circuit is connected to the input end of the secondary rectifier circuit; The high-frequency isolation and resonance circuit is used to transmit and convert electrical energy in the form of high-frequency alternating current, and output direct current to improve the efficiency of power conversion and achieve safe electrical isolation; The high-frequency DC / AC inverter circuit is connected to the output end of the secondary rectifier circuit and is used to convert direct current into alternating current for output; The control module is used to control a combination circuit consisting of the rectifier and filter circuit, the high-frequency isolation and resonance circuit, and the high-frequency DC / AC inverter circuit, and perform DC power output or AC power output based on the combination circuit.

2. The DC and low-frequency regulating dual-purpose regulated current power supply for seismic resistivity observation according to claim 1 is characterized in that: The input rectification and filtering circuit is a Vienna rectification circuit.

3. The DC and low-frequency regulating dual-purpose regulated current power supply for seismic earth resistivity observation according to claim 1 is characterized in that: The high-frequency isolation and resonance circuit is an LLC circuit that controls energy transmission by adjusting the switching frequency.

4. The DC and low-frequency regulating dual-purpose regulated current power supply for seismic earth resistivity observation according to claim 1 is characterized in that: The high-frequency DC / AC inverter circuit and control module adopt a single-phase full-bridge structure; The control module is used to control the high-frequency DC / AC inverter circuit by adopting a sinusoidal pulse width modulation (SPWM) method.

5. The DC and low-frequency regulating dual-purpose regulated current power supply for seismic earth resistivity observation according to claim 1 is characterized in that: The control module includes: a centralized control circuit, a DCAC control circuit, a DCDC control circuit, a DC output control switch, a local display control and a host computer; The DCAC control circuit, the DCDC control circuit, the DC output control switch, the local display control and the host computer are respectively connected to the centralized control circuit.

6. The DC and low-frequency regulating dual-purpose regulated current power supply for seismic earth resistivity observation according to claim 5, characterized in that: The centralized control circuit, based on the ARM controller, coordinates the control of the relationship between DC output and AC output and the host computer and local control; and controls the DCDC output power at the same time to match the AC and DC outputs; DCDC control circuit, used to control DC constant voltage and constant current output, receive instructions from the centralized control circuit, monitor and report the DC power supply operation status to the centralized control circuit; The DCAC control circuit is used to control the AC output frequency and amplitude adjustment. The frequency-controllable square wave generated by the PWM controller inside the ARM controls the output frequency; the output voltage is set by adjusting the analog quantity; the output voltage, current, and frequency status are calculated through the ADC integrated inside the ARM, and uploaded to the display board in real time, while realizing external loop adjustment, fault detection and protection control; The display and control unit is used for the display and control functions of the power supply. It obtains data from the centralized control circuit to display the output parameters and working status of the power supply.

7. The DC and low-frequency regulating dual-purpose current-stabilized power supply for seismic georesistivity observation according to claim 5 is characterized in that: The centralized control circuit includes: a shutdown desaturation circuit, a constant voltage closed-loop control circuit, a constant current closed-loop control circuit and a current cutoff competition circuit.

8. The DC and low-frequency regulating dual-purpose regulated current power supply for seismic earth resistivity observation according to claim 7, characterized in that: The constant voltage closed-loop control circuit and the constant current closed-loop control circuit are connected in parallel.

9. The DC and low-frequency regulating dual-purpose regulated current power supply for seismic earth resistivity observation according to claim 8, characterized in that: The relay of the shutdown desaturation circuit is connected to the constant voltage control given port and the constant current control given port.

10. The DC and low-frequency regulating dual-purpose current-stabilized power supply for seismic georesistivity observation according to claim 8, characterized in that: The resistors in the constant voltage closed-loop control circuit and the constant current closed-loop control circuit are high-precision resistors; and the operational amplifier in the constant current closed-loop control circuit is a high-precision operational amplifier.

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