Excitation circuit and magnetostrictive sensor

Abstract

The utility model discloses an excitation circuit and a magnetostrictive sensor. The excitation circuit comprises a signal generating unit, a voltage doubling rectifying circuit and a switch unit, the signal generating unit is used for generating a periodic signal based on the first control signal, the voltage doubling rectifying circuit is connected with the signal generating unit, and the voltage doubling rectifying circuit is used for boosting the periodic signal to generate excitation voltage; the first end of the waveguide wire is connected with the voltage doubling rectifying circuit to receive the excitation voltage, the switch unit is connected with the ground voltage and the second end of the waveguide wire, and the switch unit is used for controlling connection and disconnection between the second end of the waveguide wire and the ground voltage based on the second control signal to generate a current signal on the waveguide wire. According to the excitation circuit and the magnetostrictive sensor, the voltage doubling rectifying circuit is adopted to generate excitation voltage, pulse current is provided for the waveguide wire, the power supply voltage range of the magnetostrictive liquid level meter is wider, compatibility is higher, and the low-power-consumption requirement of the magnetostrictive sensor is met.

Description

Technical Field

[0001] The utility model belongs to the technical field of magnetostriction, in particular to an excitation circuit and a magnetostrictive sensor. Background Art

[0002] Magnetostrictive sensors are a new type of measuring device commonly used in liquid level measurement. During measurement, a magnetostrictive sensor first applies a current pulse to a waveguide filament through an excitation circuit. This current pulse is accompanied by a circular magnetic field that propagates downward along the filament at the speed of light. When this circular magnetic field encounters the magnetic field formed by the permanent magnet in the float, the combined effects of the two magnetic fields cause the waveguide filament to deform, generating a torsional wave pulse that propagates along the filament toward both ends. By detecting this torsional wave pulse signal and calculating the difference between the current pulse generation time and the strain pulse reception time, combined with the product function of the strain pulse propagation velocity, the current liquid level can be calculated.

[0003] However, traditional magnetostrictive sensors still have shortcomings in power consumption control. In order to generate strong current pulses, the excitation circuit consumes high power, which is not conducive to the overall power consumption control of the magnetostrictive sensor.

[0004] The information disclosed in this background technology section is only intended to increase the understanding of the overall background of the present invention, and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art. Utility Model Content

[0005] The purpose of the utility model is to provide an excitation circuit and a magnetostrictive sensor, which can reduce system power consumption.

[0006] In order to achieve the above-mentioned purpose, the technical solution provided by a specific embodiment of the present invention is as follows:

[0007] An excitation circuit for a magnetostrictive sensor, the magnetostrictive sensor including a waveguide filament, the excitation circuit comprising a signal generating unit, a voltage-doubling rectifier circuit, and a switching unit. The signal generating unit is configured to generate a periodic signal based on a first control signal. The voltage-doubling rectifier circuit is connected to the signal generating unit and configured to boost the periodic signal to generate an excitation voltage. A first end of the waveguide filament is connected to the voltage-doubling rectifier circuit to receive the excitation voltage. The switching unit is connected to a ground voltage and a second end of the waveguide filament and configured to control the on / off switching between the second end of the waveguide filament and the ground voltage based on a second control signal to generate a current signal on the waveguide filament.

[0008] In one or more embodiments of the present invention, the signal generating unit includes a logic operation subunit, and the logic operation subunit is used to perform a logic operation on the first control signal and generate a periodic signal.

[0009] In one or more embodiments of the present invention, the excitation circuit further includes a first resistor, a first end of the first resistor is connected to the signal generating unit, and a second end of the first resistor is connected to the voltage doubling rectifier circuit.

[0010] In one or more embodiments of the present invention, the excitation circuit further includes a diode, an anode of the diode is connected to the voltage doubler rectifier circuit to receive the excitation voltage, and a cathode of the diode is connected to the first end of the waveguide filament.

[0011] In one or more embodiments of the present invention, the excitation circuit further includes a filtering unit, which is connected to the voltage doubler rectifier circuit and the first end of the waveguide wire, and is used to filter the excitation voltage.

[0012] In one or more embodiments of the present invention, the filtering unit includes a second resistor and a capacitor, the first end of the second resistor and the first end of the capacitor are connected to the voltage doubler rectifier circuit and the first end of the waveguide wire, and the second end of the second resistor and the second end of the capacitor are connected to the ground voltage.

[0013] In one or more embodiments of the present invention, the voltage doubler rectifier circuit is an eight-fold voltage doubler circuit.

[0014] In one or more embodiments of the present invention, the switch unit includes a transistor, a control end of the transistor is used to receive a control signal, a first end of the transistor is connected to a ground voltage, and a second end of the transistor is connected to a second end of the waveguide wire.

[0015] In one or more embodiments of the present invention, the switch unit further includes a third resistor, a first end of the third resistor is connected to the control end of the transistor, and a second end of the third resistor is connected to the ground voltage.

[0016] A specific embodiment of the present utility model also provides a magnetostrictive sensor, including a control module, an excitation circuit, a waveguide wire, a permanent magnet and a detection module; the control module is used to generate a first control signal and a second control signal, and the waveguide wire is arranged close to the permanent magnet; the excitation circuit includes a signal generating unit, a voltage doubling rectifier circuit and a switch unit, the signal generating unit is connected to the control module to receive the first control signal and generate a periodic signal based on the first control signal, the voltage doubling rectifier circuit is connected to the signal generating unit, the voltage doubling rectifier circuit is used to boost the periodic signal to generate an excitation voltage, the first end of the waveguide wire is connected to the voltage doubling rectifier circuit to receive the excitation voltage, the switch unit is connected to the ground voltage and the second end of the waveguide wire, the switch unit is connected to the control module to receive the second control signal and control the connection and disconnection between the second end of the waveguide wire and the ground voltage based on the second control signal to generate a current signal on the waveguide wire, and cause the waveguide wire to generate a torsional wave signal at the permanent magnet, and the detection module is inductively connected to the waveguide wire to sense the torsional wave signal and generate an induction signal.

[0017] Compared with the existing technology, the excitation circuit and magnetostrictive sensor of the present invention use a voltage-doubling rectifier circuit to generate an excitation voltage, providing a pulse current for the waveguide wire, making the power supply voltage range of the magnetostrictive liquid level meter wider and more compatible, thus meeting the low power consumption requirements of the magnetostrictive sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 This is a system structure diagram of a magnetostrictive sensor in one embodiment of the present invention.

[0020] Figure 2 1 is a circuit schematic diagram of an excitation circuit in one embodiment of the present invention. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the following will be combined with the drawings of the embodiments of the present invention to clearly and completely describe the technical solutions of the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0022] The terms "coupled," "connected," or "connected" as used in this specification encompass both direct and indirect connections. An indirect connection is a connection made through an intermediate medium, such as an electrically conductive medium, which may have parasitic inductance or capacitance. An indirect connection may also include a connection through other active or passive devices, such as switches, follower circuits, or other circuits or components, to achieve the same or similar functional objectives. Furthermore, in the invention, terms such as "first" and "second" are primarily used to distinguish one technical feature from another and do not necessarily require or imply a specific relationship, quantity, or order between these technical features.

[0023] In the detailed description of the specification, reference is made to the accompanying drawings forming a part thereof, wherein like reference numerals designate like parts throughout, and wherein exemplary embodiments that may be implemented are shown by way of example. It should be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure. Therefore, the following detailed description should not be construed in a limiting sense.

[0024] The various operations in the specification may be described as multiple discrete actions or operations in a manner that is most helpful in understanding the claimed subject matter. However, the order of description should not be interpreted as implying that these operations must be sequentially related. Specifically, these operations may not be performed in the order presented. The described operations may be performed in an order different from the described embodiments. Various additional operations may be performed and / or the described operations may be omitted in additional embodiments.

[0025] For the purposes of this disclosure, the phrase "A and / or B" means (A), (B), or (A and B). For the purposes of this disclosure, the phrase "A, B and / or C" means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).

[0026] Various components and devices may be referred to or shown in the singular form in this document (for example, "MOS tube", "transistor", "switch", etc.), but this is only for convenience of discussion, and any element referred to in the singular form may include multiple such elements according to the teachings of this document.

[0027] The specification uses the phrases "in one embodiment," "in other embodiments," or "in some embodiments," which can each refer to one or more of the same or different embodiments. In addition, the terms "including," "comprising," "having," etc. used with respect to the embodiments of the present disclosure are synonymous.

[0028] like Figure 1 and Figure 2As shown, the magnetostrictive sensor in one embodiment of the present invention includes a control module 10 , an excitation circuit 20 , a waveguide wire, a permanent magnet and a detection module 30 .

[0029] The control module 10 is used to generate a first control signal and a second control signal, and the waveguide wire is arranged close to the permanent magnet.

[0030] The excitation circuit 20 includes a signal generating unit, a voltage doubling rectifier circuit, a switching unit, a filtering unit, a first resistor R3 and a diode D4. The signal generating unit is connected to the control module 10 to receive a first control signal and generate a periodic signal based on the first control signal. The first end of the first resistor R3 is connected to the signal generating unit to receive the periodic signal. The voltage doubling rectifier circuit is connected to the second end of the first resistor R3. The voltage doubling rectifier circuit is used to boost the periodic signal to generate an excitation voltage. The first resistor R3 is used to limit current.

[0031] The anode of diode D4 is connected to the voltage-doubling rectifier circuit to receive the excitation voltage. The cathode of diode D4 is connected to a filter unit, which is connected to the first end of the waveguide filament. The filter unit is used to filter the excitation voltage, and diode D4 is used to prevent the current in the waveguide filament from flowing back into the voltage-doubling rectifier circuit.

[0032] The switching unit is connected to the ground voltage and the second end of the waveguide wire. The switching unit is connected to the control module 10 to receive a second control signal and control the on and off between the second end of the waveguide wire and the ground voltage based on the second control signal to generate a current signal on the waveguide wire and cause the waveguide wire to generate a torsional wave signal at the permanent magnet.

[0033] The detection module 30 is inductively connected to the waveguide wire to sense the torsional wave signal and generate a sensing signal.

[0034] In one embodiment, a permanent magnet is disposed in the float. When the excitation circuit generates a current signal on the waveguide wire, the current signal will be accompanied by a circular magnetic field, which propagates downward along the waveguide wire at the speed of light. When the circular magnetic field encounters the magnetic field formed by the permanent magnet, the waveguide wire will be deformed under the action of the two magnetic fields, generating a torsional wave pulse. The torsional wave pulse propagates along the waveguide wire to both ends, and the detection module detects the torsional wave pulse and generates an induction signal. The detection module can send the induction signal to the control module or external device, and by calculating the time difference between the induction signal and the current signal generated on the waveguide wire, the current liquid level value can be further calculated. This embodiment does not involve any structural improvements to the magnetostrictive sensor other than the excitation circuit, and can be implemented using existing technologies, which will not be repeated here.

[0035] like Figure 2 As shown, the signal generating unit includes a logic operation subunit, which is used to perform a logic operation on the first control signal and generate a periodic signal.

[0036] In one embodiment, the logic operation subunit includes a logic gate chip U4, model number 74HCT1G02GV, which is a NOR gate. There are two sets of first control signals: a first control signal PW_EN and a first control signal PW_PL. Pin 1 of the logic gate chip U4 is connected to the control module 10 to receive the first control signal PW_EN, and pin 2 of the logic gate chip U4 is connected to the control module 10 to receive the first control signal PW_PL. Controlled by the first control signals PW_EN and PW_PL, the logic gate chip U4 outputs a 0V to 5V square wave signal on its pin 4. Pin 4 of the logic gate chip U4 is connected to the first end of the first resistor R3.

[0037] In one embodiment, the voltage doubler rectifier circuit includes an octave voltage doubler circuit.

[0038] like Figure 2 As shown in Figure 1, the eightfold voltage multiplier circuit includes capacitors C12-C15, C17-C20, and diodes D5-D12. This circuit utilizes the rectifying and steering properties of the diodes to store voltages on their respective capacitors. These capacitors are then connected in series based on the principle of polarity addition, resulting in a high voltage output higher than the input voltage. Theoretically, this circuit can generate a 40V voltage across capacitor C15 and the cathode of diode D6.

[0039] In other embodiments, voltage doubling rectifier circuits with other multiples may also be used.

[0040] The filtering unit includes a capacitor C16 and a second resistor R4. The first end of the capacitor C16 and the first end of the second resistor R4 are connected to the cathode of the diode D4 and the first end of the waveguide wire. The second end of the capacitor C16 and the second end of the resistor R4 are connected to the ground voltage.

[0041] like Figure 2 As shown, the switch unit includes a transistor Q2 and a third resistor R7. A first terminal of the transistor Q2 and a second terminal of the third resistor R7 are connected to a ground voltage, a second terminal of the transistor Q2 is connected to a second end of the waveguide filament, and a control terminal of the transistor Q2 and a first terminal of the third resistor R7 are connected to a control module 10 to receive a second control signal.

[0042] In one embodiment, the transistor Q2 is an NMOS transistor, the first end of the transistor Q2 is a source, the second end of the transistor Q2 is a drain, and the control end of the transistor Q2 is a gate.

[0043] When the second control signal is at a low level, transistor Q2 is turned off, disconnecting the second end of the waveguide from the ground voltage. When the second control signal is at a high level, transistor Q2 is turned on, connecting the second end of the waveguide to the ground voltage, and generating a current signal on the waveguide.

[0044] In other embodiments, the transistor Q2 may also be a PMOS transistor, and its connection method and control method are adaptively adjusted.

[0045] In other embodiments, one or more of the filter unit, the first resistor R3 and the diode D4 may not be provided.

[0046] In actual application, the control module 10 controls the logic gate chip U4 to output a square wave signal through the first control signal PW_EN and the first control signal PW_PL, and disconnects the waveguide filament from the ground voltage through a low-level second control signal. The voltage doubler rectifier circuit continuously accumulates charge on the waveguide filament. Until the excitation voltage reaches the required voltage value, such as 20V, the control module 20 generates a high-level second control signal. The moment the second end of the waveguide filament is connected to the ground voltage, a large pulse current signal is generated on the waveguide filament, which is further sensed by the permanent magnet and the detection module 30 to generate an induction signal. Compared with the traditional method of using an LDO power supply chip to provide excitation voltage for the waveguide filament, the voltage doubler rectifier circuit in this solution can greatly reduce power consumption and meet the low power consumption requirements of the system. By adopting an eight-fold voltage multiplier circuit, the 5V square wave voltage can be quickly raised to the required 20V.

[0047] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be encompassed within the present invention. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0048] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. An excitation circuit for a magnetostrictive sensor, wherein the magnetostrictive sensor comprises a waveguide wire, characterized in that: The excitation circuit includes a signal generating unit, a voltage doubling rectifier circuit and a switching unit. The signal generating unit is used to generate a periodic signal based on a first control signal. The voltage doubling rectifier circuit is connected to the signal generating unit. The voltage doubling rectifier circuit is used to boost the periodic signal to generate an excitation voltage. The first end of the waveguide wire is connected to the voltage doubling rectifier circuit to receive the excitation voltage. The switching unit is connected to the ground voltage and the second end of the waveguide wire. The switching unit is used to control the on and off between the second end of the waveguide wire and the ground voltage based on the second control signal to generate a current signal on the waveguide wire.

2. The excitation circuit according to claim 1, characterized in that The signal generating unit includes a logic operation subunit, and the logic operation subunit is used to perform a logic operation on the first control signal and generate a periodic signal.

3. The excitation circuit according to claim 1, characterized in that The excitation circuit further includes a first resistor, a first end of the first resistor is connected to the signal generating unit, and a second end of the first resistor is connected to the voltage doubling rectifier circuit.

4. The excitation circuit according to claim 1, characterized in that The excitation circuit further includes a diode, an anode of the diode is connected to the voltage doubler rectifier circuit to receive the excitation voltage, and a cathode of the diode is connected to the first end of the waveguide wire.

5. The excitation circuit according to claim 1, characterized in that: The excitation circuit further includes a filtering unit, which is connected to the voltage doubler and rectifier circuit and the first end of the waveguide wire, and is used to filter the excitation voltage.

6. The excitation circuit according to claim 5, characterized in that: The filtering unit includes a second resistor and a capacitor, the first end of the second resistor and the first end of the capacitor are connected to the voltage doubler rectifier circuit and the first end of the waveguide wire, and the second end of the second resistor and the second end of the capacitor are connected to the ground voltage.

7. The excitation circuit according to claim 1, characterized in that: The voltage doubler rectifier circuit is an eight-fold voltage doubler circuit.

8. The excitation circuit according to claim 1, characterized in that: The switch unit includes a transistor, a control end of the transistor is used to receive a control signal, a first end of the transistor is connected to a ground voltage, and a second end of the transistor is connected to a second end of the waveguide wire.

9. The excitation circuit according to claim 8, characterized in that: The switch unit further includes a third resistor, a first end of the third resistor is connected to the control end of the transistor, and a second end of the third resistor is connected to the ground voltage.

10. A magnetostrictive sensor, characterized in that: It includes a control module, an excitation circuit, a waveguide wire, a permanent magnet and a detection module; The control module is used to generate a first control signal and a second control signal, and the waveguide wire is arranged close to the permanent magnet; The excitation circuit includes a signal generating unit, a voltage doubling rectifier circuit and a switching unit. The signal generating unit is connected to the control module to receive a first control signal and generate a periodic signal based on the first control signal. The voltage doubling rectifier circuit is connected to the signal generating unit. The voltage doubling rectifier circuit is used to boost the periodic signal to generate an excitation voltage. The first end of the waveguide wire is connected to the voltage doubling rectifier circuit to receive the excitation voltage. The switching unit is connected to the ground voltage and the second end of the waveguide wire. The switching unit is connected to the control module to receive a second control signal and control the on and off between the second end of the waveguide wire and the ground voltage based on the second control signal to generate a current signal on the waveguide wire, and enable the waveguide wire to generate a torsional wave signal at the permanent magnet. The detection module is inductively connected to the waveguide wire to sense the torsional wave signal and generate an induction signal.

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