Excitation source circuit and inductive displacement sensor

Abstract

An excitation source circuit comprises a sinusoidal signal generation circuit, a D-type power amplification circuit, an LC filter and a push-pull switching power supply circuit. The sinusoidal signal generation circuit is used for outputting a sinusoidal signal; the D-type power amplification circuit is electrically connected with the sinusoidal signal generation circuit, and the D-type power amplification circuit realizes the amplification of a sinusoidal signal by controlling the on and off of a power switching device; the LC filter is electrically connected with the D-type power amplification circuit, and the LC filter processes the amplified sinusoidal signal and then outputs a driving signal; the push-pull switching power supply circuit is used for supplying power to the D-type power amplification circuit. According to the utility model, the noise of the excitation source circuit is reduced, and the measurement precision of the inductive displacement sensor is further improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of excitation source, specifically to an excitation source circuit and inductive displacement sensor. BACKGROUND

[0002] The inductive displacement sensor is a non-contact measuring device based on electromagnetic induction principle, and is widely used in industrial automation, precision measurement and many other fields due to its unique measurement method. In the composition of the inductive displacement sensor, the excitation source plays a crucial role, and its performance directly affects the measurement accuracy and stability of the inductive displacement sensor.

[0003] However, most of the traditional excitation source devices use analog circuits or analog and digital hybrid circuits to achieve this. This design has a high noise level. The existence of noise will interfere with the measurement signal and reduce the quality of the signal, resulting in a decrease in the measurement accuracy of the inductive displacement sensor, making it difficult to meet the needs of high-precision and high-stability measurement. UTILITY MODEL CONTENT

[0004] In order to solve the problem of high noise level of the traditional excitation source device in the prior art, which leads to a decrease in measurement accuracy, the utility model provides an excitation source circuit and an inductive displacement sensor, which reduces the noise of the excitation source circuit and improves the measurement accuracy of the inductive displacement sensor.

[0005] The utility model adopts the technical scheme that: an excitation source circuit, including sinusoidal signal generating circuit, D class power amplifier circuit, LC filter and push-pull switching power supply circuit;

[0006] The sinusoidal signal generating circuit is used to output a sinusoidal signal.

[0007] The D class power amplifier circuit is electrically connected with the sinusoidal signal generating circuit. The D class power amplifier circuit realizes the amplification of the sinusoidal signal by controlling the conduction and shutdown of the power switching device.

[0008] The LC filter is electrically connected with the D class power amplifier circuit. The LC filter outputs a driving signal after processing the amplified sinusoidal signal.

[0009] The push-pull switching power supply circuit is used to supply power to the D class power amplifier circuit.

[0010] As a further optimization of the utility model an excitation source circuit: the sinusoidal signal generating circuit includes a phase shift oscillator and three series RC oscillation circuits electrically connected, and a buffer is connected in each RC oscillation circuit.

[0011] As a further optimization of the utility model an excitation source circuit: the push-pull switching power supply circuit includes two power switching devices electrically connected.

[0012] As a further optimization of the excitation source circuit of the utility model: the D class power amplifier circuit comprises a power bridge circuit and a plurality of passive devices.

[0013] The utility model discloses a technical scheme that solves the above technical problems: an inductive displacement sensor, comprising a displacement sensor body, a mounting mechanism and the excitation source circuit of any one of the above, the coil in the displacement sensor body receives the drive signal and generates a magnetic field, the mounting mechanism comprises a containing shell fixedly arranged on the displacement sensor body, and the excitation source circuit is arranged in the containing shell.

[0014] As a further optimization of the inductive displacement sensor of the utility model: a cover is arranged on the containing shell, and the inner wall of the containing shell and the bottom of the cover are both provided with a shielding layer.

[0015] As a further optimization of the inductive displacement sensor of the utility model: the cover is fixedly connected with the containing shell through connecting bolts.

[0016] As a further optimization of the inductive displacement sensor of the utility model: a mounting seat is arranged on the displacement sensor body, a through hole is formed in the mounting seat, a connecting rod is fixedly connected to the top of the cover, and the connecting rod is fixed through a nut after penetrating through the through hole.

[0017] Compared with the prior art, the utility model has the beneficial effects that:

[0018] The utility model discloses a D class power amplifier circuit, a sinusoidal signal generating circuit and an LC filter are arranged, the efficiency of the excitation source circuit can be improved, the power consumption of the excitation source circuit can be reduced, the noise of the excitation source circuit can be reduced, the purity and stability of the excitation signal can be improved, and the measurement precision of the inductive displacement sensor can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is the structure schematic diagram of the utility model;

[0020] Figure 2 It is the schematic diagram of sinusoidal signal generating circuit;

[0021] Figure 3 It is the schematic diagram of D class power amplifier circuit and LC filter circuit;

[0022] Figure 4 It is the schematic diagram of push-pull switching power supply circuit;

[0023] Figure 5 It is the structure schematic diagram of inductive displacement sensor;

[0024] Figure 6 It is the schematic diagram of containing shell, cover and shielding layer cooperation;

[0025] Marked in the figure: 1, displacement sensor body, 2, mounting seat, 3, containing shell, 4, cover, 5, nut, 6, connecting rod, 7, shielding layer, 8, connecting bolt. DETAILED DESCRIPTION

[0026] The technical scheme of the utility model will be further described in detail below in combination with specific embodiments. The parts not described and disclosed in the following embodiments of the utility model should be understood as the prior art known or should be known by the person skilled in the art, such as the working principle of the inductive displacement sensor, the model of the phase shift oscillator, the model of the buffer, the structure of the power bridge circuit and the passive device, the material and shielding principle of the shielding layer, etc.

[0027] An excitation source circuit, as shown in Figure 1 , comprises a sinusoidal signal generating circuit, a class-D power amplification circuit, an LC filter and a push-pull switching power supply circuit. As shown in Figures 2 to 4 , the sinusoidal signal generating circuit is used for outputting a sinusoidal signal, and the sinusoidal signal has a certain frequency and amplitude; the sinusoidal signal generating circuit comprises a phase shift oscillator and three series-connected RC oscillation circuits electrically connected, and the phase shift oscillator has the advantages of small distortion and good frequency stability; a buffer is connected in each RC oscillation circuit to obtain a frequency and gain close to theoretical calculation. The sinusoidal signal generating circuit can be provided with different frequency and amplitude parameters to meet the needs of different inductive displacement sensors.

[0028] The class-D power amplification circuit is electrically connected with the sinusoidal signal generating circuit, and the class-D power amplification circuit realizes amplification of the sinusoidal signal by controlling the conduction and shutdown of the power switching device; the class-D power amplification circuit is designed based on the existing D-class power amplifier topology, takes the IRS2092 chip as the core, and has the functions of overload protection and overheat protection, which can ensure the safe and stable operation of the circuit. The IRS2092 chip has the following advantages: its output swing rate is as high as ±100V, and it can realize power output of more than 500W; the maximum working frequency can reach 800kHz. In addition, the class-D power amplification circuit also integrates the PWM modulation circuit, the overcurrent protection function of the high-voltage side and the low-voltage side, and the programmable dead time. The class-D power amplification circuit comprises a power bridge circuit and a plurality of passive devices.

[0029] As shown in Figure 3As shown, Vin is the input voltage, filtered by a 10uF capacitor, and then connected to the VAA pin of the IRS2092 through a 2.7KΩ resistor, VAA is the analog input pin of the IRS2092, which receives the filtered and current-limited input signal; GND is the ground line, connected to multiple points in the circuit, including the other end of the input capacitor and the GND pin of the IRS2092; IN- and IN+ are the differential input pins of the IRS2092, connected to VAA and GND through a capacitor and resistor network; Vcc provides a 12V operating voltage to the IRS2092 chip, Vcc is connected to a 12V power supply; VSS is the power ground, connected to GND; COMP is the compensation pin, grounded through a 510Ω resistor and a 1nF capacitor, used to stabilize the amplifier; VREF is the reference voltage pin, grounded through a 10uF capacitor; OCSET is the overcurrent protection setting pin, grounded through an 8.2kΩ resistor; DT is the dead time control pin, grounded through a 12kΩ resistor; VB and HO are the high-side power supply and high-side output pins, respectively, connected to the gate of the high-side MOSFET; LO is the low-side output pin, connected to the gate of the low-side MOSFET; VS is the high-side power supply sensing pin, grounded through a 22uF capacitor; COM is the common ground, connected to GND; two N-channel MOSFETs of type IRF6645 serve as high-side and low-side power switches, respectively; a Schottky diode of type MURS120 is used to protect the MOSFET from reverse voltage; +B and -B provide ±35V power supply for the output stage; a 10KΩ resistor connected between VB and HO is used to set the gate voltage of the high-side MOSFET; a 33KΩ resistor connected between VS and VCC is used to set the reference voltage of the high-side power supply sensing pin.

[0030] The LC filter is electrically connected with the D-class power amplification circuit, and outputs a driving signal after processing the amplified sinusoidal signal. The LC filter is used to filter out high-frequency noise and spurs of the amplified sinusoidal signal output by the D-class power amplification circuit. It adopts a series resonant circuit composed of inductance and capacitance, and by reasonably selecting the inductance value and capacitance value, it has excellent filtering performance in the target frequency range, effectively filters out high-frequency noise and spurs, thereby improving the purity and stability of the excitation signal. In addition, the driving signal output by the LC filter is the driving signal output by the entire excitation source circuit, which is used to drive the coil of the inductive displacement sensor.

[0031] The push-pull switching power supply circuit is used for supplying power to a class-D power amplifier circuit. The push-pull switching power supply circuit comprises two electrically connected power switching devices. The design of the push-pull switching power supply circuit needs to consider the stability, efficiency and ripple of the power supply. The push-pull switching power supply circuit adopts a push-pull topology structure, and realizes high-efficiency conversion from an input DC voltage to an output DC voltage by controlling the alternate conduction and turn-off of two N-channel MOSFETs of IRF6645 type. The circuit has the advantages of high efficiency, high stability and low ripple, and can meet the high requirements of the excitation source circuit on the power supply, and provide stable power supply for the entire excitation source circuit.

[0032] An inductive displacement sensor, as shown in Figure 5 and Figure 6 includes a displacement sensor body 1, a mounting mechanism and an excitation source circuit as claimed in any one of the preceding claims, the coil in the displacement sensor body 1 receives the driving signal and generates a magnetic field, the mounting mechanism includes a containing shell 3 fixedly arranged on the displacement sensor body 1, and the excitation source circuit is arranged in the containing shell 3. In order to protect the excitation source circuit in the containing shell 3, a cover 4 is arranged on the containing shell 3, and a shielding layer 7 is arranged on the inner wall of the containing shell 3 and the bottom of the cover 4, which is used to prevent the magnetic field of the coil from interfering with the excitation source circuit. In order to ensure the fastening connection between the cover 4 and the containing shell 3, the cover 4 is fixedly connected with the containing shell 3 through connecting bolts 8. After the excitation source circuit is placed in the containing shell 3, the top of the containing shell 3 is sealed by the cover 4, and then is fastened and fixed by the connecting bolts 8 and connecting nuts 5. In order to facilitate the connection between the containing shell 3 and the displacement sensor body 1, a mounting seat 2 is arranged on the displacement sensor body 1, a through hole is formed in the mounting seat 2, the top of the cover 4 is fixedly connected with a connecting rod 6, the containing shell 3 is sealed by the cover 4, and then is fixed by the connecting bolts 8 and the connecting nuts 5, and then the connecting rod 6 is passed through the through hole and is fixed by a nut.

[0033] The above description of disclosed embodiments enables those skilled in the art to carry out or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An excitation source circuit, characterized by: The sinusoidal signal generating circuit, the class-D power amplification circuit, the LC filter and the push-pull switching power supply circuit are connected in series. The sinusoidal signal generating circuit is used for outputting a sinusoidal signal. The class-D power amplification circuit is electrically connected with the sinusoidal signal generating circuit. The LC filter is electrically connected with the class-D power amplification circuit.

2. The excitation source circuit of claim 1, wherein: The push-pull switching power supply circuit is used for supplying power to the class-D power amplification circuit.

3. The excitation source circuit of claim 1, wherein: The sinusoidal signal generating circuit comprises a phase-shift oscillator and three RC oscillation circuits connected in series.

4. The excitation source circuit of claim 1, wherein: The push-pull switching power supply circuit comprises two power switching devices connected in series.

5. Inductive displacement sensor, characterized in that: The class-D power amplification circuit comprises a power bridge circuit and a plurality of passive devices.

6. An inductive displacement sensor as claimed in claim 5, characterised in that: The displacement sensor body (1) is provided with a mounting seat (2), and a through hole is formed in the mounting seat (2).

7. An inductive displacement sensor as claimed in claim 6, characterised in that: The top of the cover (4) is fixedly connected with a connecting rod (6), and the connecting rod (6) passes through the through hole and is fixed by a nut (5).

8. The inductive displacement sensor of claim 6, wherein: ​

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