CN115201576A - Novel method and system for detecting equivalent inductance with high precision - Google Patents

Abstract

The invention relates to the technical field of sensors, in particular to a novel method and a system for detecting equivalent inductance with high precision, wherein a detection circuit is formed by connecting a resistor, a constant current source circuit and a planar coil inductor in parallel, the planar coil inductor is printed on a PCB (printed circuit board), the coil routing of the planar coil inductor enables the direction of a magnetic field generated by current to be consistent, a high-precision timer is connected with the planar coil inductor through a selection switch, the high-precision timer controls the selection switch through CCR1A, and the high-precision timer controls the detection circuit through CCR 2A.

Description

A Novel Method and System for Measuring Equivalent Inductance with High Precision

technical field

The invention relates to the technical field of sensors, in particular to a novel method and system for detecting equivalent inductance with high precision.

Background technique

The angular position sensor can detect the rotational angular displacement of the detected target. The angular position sensor is mainly used in the flow meter, industrial machine tool and robot industry. Metal displacement sensors are mainly used in industrial machine tools, robots, and industrial Internet of Things industries.

At present, the angular displacement and displacement sensors in the industry are mainly based on light. The detection method is generally to detect the change of the amplitude or frequency of the LC oscillation. The anti-interference is relatively weak, and is greatly affected by temperature drift.

Based on the above reasons, the present invention designs a novel high-precision equivalent inductance detection method and system, which detects the equivalent inductance value of the output signal of the induction coil, which is suitable for the working environment of micro-power consumption and micro-signal, and can be applied For angular displacement and metal displacement sensor products, it is easy to produce, has high accuracy and strong anti-interference.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies of the prior art, and to provide a novel method and system for detecting equivalent inductance with high precision, which can detect the equivalent inductance value of the output signal of the induction coil, and is suitable for the detection of micro-power consumption and micro-signal. Working environment, can be applied to angular displacement and metal displacement sensor products, easy to produce, high accuracy, strong anti-interference.

In order to achieve the above purpose, the present invention provides a novel high-precision detection equivalent inductance system, which is composed of a PCB circuit board, a plane coil inductance, a detection circuit and a high-precision timer. The detection circuit is composed of a resistor, a constant current source circuit and a plane coil inductance. It is composed of parallel connection. The plane coil inductance is printed on the PCB circuit board. The coil wiring of the plane coil inductance makes the direction of the magnetic field generated by the current consistent. The high-precision timer is connected to the plane coil inductance through the selection switch. switch, the high-precision timer controls the detection circuit through the CCR2A.

A novel high-precision detection method for equivalent inductance includes the following steps:

At time S1 and T0, the selection switch is connected to the constant current source circuit, and at the same time, the high-precision timer is started to work, the constant current source circuit discharges the inductance of the plane coil, and the current through the inductance of the plane coil reaches a stable value;

At time S2 and T1, the high-precision timer counts up, the timer CCR1A is enabled, and the selection switch is connected to the resistor;

At time S3 and T2, when the high-precision timer counts up, the timer CCR2A is enabled, and the detection circuit is activated to start working;

S4, the detection circuit calculates the equivalent inductance value by detecting the voltage across the resistor at time T2;

The specific algorithm of S4 is as follows:

The initial value of the inductor current is: i _l (0 ₊ )=i _l (0 _- )=I ₀ ;

Circuit current:

Resistor Voltage:

I ₀ is the initial current of the constant current source; UR is the decay function with stable initial amplitude, _R is the resistance value, _UR is the detected value, the time t=T2-T1 is obtained by a high-precision timer, and calculated by the formula deformation Get the equivalent inductance L value.

When the detection circuit detects _UR , a first-order differential circuit can be added inside the detection circuit to detect the rate of change of _UR .

The detection circuit calculates the equivalent inductance L value by detecting the time window when _UR changes to a certain fixed voltage _UT , and the value of _UT ranges from 0 to RI ₀ .

Compared with the prior art, the present invention can effectively measure the voltage value at both ends of the resistor and obtain the corresponding equivalent inductance value by setting a detection circuit on the planar coil inductance and controlling the selection switch through a high-precision timer, thereby realizing the The equivalent inductance value is detected in the working environment of micro power consumption and micro signal, which can be applied to sensor products of angular displacement and metal displacement, which is convenient for production, high accuracy and strong anti-interference.

Description of drawings

FIG. 1 is a schematic diagram of the exponential circuit of the algorithm of the present invention.

Figure 2 is a schematic diagram of the discharge of the planar coil inductance to the resistance.

FIG. 3 is a schematic diagram of the detection state of the present invention.

FIG. 4 is a schematic diagram of adding a first-order differential circuit to the detection circuit of the present invention.

Detailed ways

The present invention will now be further described with reference to the accompanying drawings.

Referring to Figures 1 to 4, the present invention provides a new method and system for high-precision detection of equivalent inductance, which is composed of a PCB circuit board, a planar coil inductance, a detection circuit and a high-precision timer. The detection circuit is composed of a resistor and a constant current source circuit. It is formed by connecting in parallel with the planar coil inductor. The planar coil inductor is printed on the PCB circuit board. The coil wiring of the planar coil inductor makes the direction of the magnetic field generated by the current consistent. The high-precision timer is connected to the planar coil inductor through the selector switch. The selector switch is controlled by CCR1A, and the detection circuit is controlled by the high-precision timer through CCR2A.

A novel high-precision detection method for equivalent inductance includes the following steps:

At time S1 and T0, the selection switch is connected to the constant current source circuit, and at the same time, the high-precision timer is started to work, the constant current source circuit discharges the inductance of the plane coil, and the current through the inductance of the plane coil reaches a stable value;

At time S2 and T1, when the high-precision timer counts up, the timer CCR1A is enabled, and the selection switch is connected to the resistor to discharge the planar coil inductance with an initial stable current to the resistor;

At time S3 and T2, when the high-precision timer counts up, the timer CCR2A is enabled, and the detection circuit is activated to start working;

S4, the detection circuit calculates the equivalent inductance value by detecting the voltage across the resistor at time T2;

The specific algorithm of S4 is as follows:

The initial value of the inductor current is: i _l (0 ₊ )=i _l (0 _- )=I ₀ ;

Circuit current:

Resistor Voltage:

I ₀ is the initial current of the constant current source; UR is the decay function with stable initial amplitude, _R is the resistance value, _UR is the detected value, the time t=T2-T1 is obtained by a high-precision timer, and calculated by the formula deformation Get the equivalent inductance L value.

Through the first-order differential circuit, the rate of change of _UR will amplify the signal by at least ten thousand times, which is convenient for weak signal detection, improves the detection accuracy, and improves the anti-interference degree.

The detection circuit calculates the equivalent inductance L value by detecting the time window when _UR changes to a certain fixed voltage _UT , and the value of _UT ranges from 0 to RI ₀ .

Example:

Please refer to FIG. 1 to FIG. 4 , the present invention provides a novel method and system for detecting equivalent inductance with high precision:

When the detected metal object is far away from the induction coil, that is, the inductance of the plane coil, at T0, the selector switch C is connected to A, and the high-precision timer is started to work at the same time. At this time, the constant current source circuit discharges the inductance of the plane coil. The current reaches a stable value;

When the high-precision timer counts the time T1, the timer CCR1A is enabled, the selection switch C is disconnected from A, and connected to B, so that the planar coil inductance with an initial stable current discharges to the resistor;

When the high-precision timer counts time T2, the timer CCR2A is enabled, and the detection circuit is activated to start working; the detection circuit detects the voltage U _R 11 across the resistor at the time of T2.

When the detected metal object is close to the induction coil, that is, the inductance of the plane coil, at T0, the selector switch C is connected to A, and the high-precision timer is started at the same time. reach a stable value;

When the high-precision timer counts the time T1, the timer CCR1A is enabled, the selection switch C is disconnected from A, and connected to B, so that the planar coil inductance with an initial stable current discharges to the resistor;

When the high-precision timer counts time T2, the timer CCR2A is enabled, and the detection circuit is activated to start working; the detection circuit detects the voltage _UR 22 across the resistor at the time of T2.

The values of _UR 11 and _UR 22 are definitely different, and the difference between _UR 11 and _UR 22 is caused by the change of the equivalent inductance value caused by the distance and proximity of metal objects.

The above are only the preferred embodiments of the present invention, and are only used to help understand the method and the core idea of the present application. The protection scope of the present invention is not limited to the above-mentioned embodiments, and all technical solutions under the idea of the present invention belong to the present invention. scope of protection. It should be pointed out that for those skilled in the art, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

The invention as a whole solves the problems in the prior art that it is difficult to detect micro-signals and micro-power consumption, and the anti-interference of frequency detection is relatively weak and greatly affected by temperature drift. A detection circuit is set up, and the selector switch is controlled by a high-precision timer, which can effectively measure the voltage value across the resistor and obtain the corresponding equivalent inductance value. It can be applied to sensor products of angular displacement and metal displacement, which is convenient for production and accuracy. High, strong anti-interference.

Claims (5)

1. A novel high-precision detection equivalent inductance system is characterized in that, it is composed of a PCB circuit board, a plane coil inductance, a detection circuit and a high-precision timer, and the detection circuit is composed of a resistance, a constant current source circuit and a plane coil inductance. It consists of a parallel connection, the planar coil inductor is printed on the PCB circuit board, the coil wiring of the planar coil inductor makes the direction of the magnetic field generated by the current consistent, and the high-precision timer is connected to the planar coil inductor through a selection switch. connected, the high-precision timer controls the selection switch through CCR1A, and the high-precision timer controls the detection circuit through CCR2A. 2. A novel high-precision detection equivalent inductance method of the system according to claim 1, characterized in that, comprising the following steps: At time S1 and T0, the selection switch is connected to the constant current source circuit, and at the same time, the high-precision timer is started to work, the constant current source circuit discharges the inductance of the plane coil, and the current through the inductance of the plane coil reaches a stable value; At time S2 and T1, the high-precision timer counts up, the timer CCR1A is enabled, and the selection switch is connected to the resistor; At time S3 and T2, when the high-precision timer counts up, the timer CCR2A is enabled, and the detection circuit is activated to start working; S4, the detection circuit calculates the equivalent inductance value by detecting the voltage across the resistor at time T2. 3. a kind of novel high-precision detection equivalent inductance method according to claim 2, is characterized in that, the concrete algorithm of described S4 is as follows: The initial value of the inductor current is: i _l (0 ₊ )=i _l (0 _- )=I ₀ ; Circuit current:

Resistor Voltage:

The I ₀ is the initial current of the constant current source; the UR is the decay function with stable initial amplitude, the _R is the resistance value, the _UR is the detected value, and the time t=T2-T1 passes the high precision The timer is obtained, and the equivalent inductance L value is calculated through the deformation of the formula. 4. a kind of novel high-precision detection equivalent inductance method according to claim 2 is characterized in that, when the described detection circuit detects _UR , a first-order differential circuit can be added inside the detection circuit to detect the change of _UR Rate. 5. A novel high-precision detection equivalent inductance method according to claim 2, wherein the detection circuit calculates the equivalent inductance L by detecting the time window in which _UR changes to a certain fixed voltage _UT value, the U _T value ranges from 0 to RI ₀ .

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