Engine rotating speed signal measuring circuit

Abstract

The utility model discloses an engine rotating speed signal measuring circuit, which belongs to the related technical field of signal measurement and comprises a positive end resistor R3 connected with a rotating speed input signal positive end S1 +, a negative end resistor R4 connected with a rotating speed input signal negative end S1-, an operational amplifier U0, a comparator and a signal conversion circuit. A rotating speed input signal negative end S1-is connected with a reference circuit in parallel and then is connected to a negative input pin of the operational amplifier U0, and the reference circuit is additionally arranged between the rotating speed input signal negative end S1-and the negative input pin of the operational amplifier U0. The interference signal is prevented from influencing the conditioning precision of the conditioning circuit on the rotating speed signal in the use process; and on the other hand, the magnitude of the threshold voltage is determined by the magnitude of the partial voltage of the reference circuit, so that the signal overturning of the frequency signal caused by interference when the threshold voltage accessory changes is reduced, the measurement accuracy is improved, and the problem that the error of the measured rotating speed signal is large due to the interference generated in the operation of the engine is solved.

Description

Technical Field

[0001] The utility model relates to the technical field related to signal measurement, in particular to an engine speed signal measurement circuit. Background Art

[0002] With the development of aerospace technology, the thrust of rocket engines is increasing day by day, and the monitoring of the core parameters of the engine is particularly important, especially in the new generation of liquid engines, there are many key measurement points involved in engine control, such as temperature, pressure, vibration, speed, liquid level, etc., and the accuracy requirements of the measured data must also be guaranteed. Therefore, high-precision and real-time measurement capabilities are the basis and prerequisite for ensuring that it can operate smoothly in a healthy and safe state.

[0003] Engine speed is a key parameter for evaluating engine performance. At present, the engine speed signal adopts the principle of electromagnetic induction, that is, the induced electromotive force is generated by cutting the magnetic flux lines by a coil. However, in actual use, interference is easily generated, resulting in poor accuracy of the measured speed. Therefore, it is urgent to provide an engine speed signal measurement circuit to solve the problem of large error in the measured speed signal caused by interference generated during engine operation. Utility Model Content

[0004] The utility model provides an engine speed signal measurement circuit, aiming to solve the above technical defects.

[0005] The specific technical solutions provided by the utility model are as follows:

[0006] The utility model provides an engine speed signal measurement circuit, comprising a positive terminal resistor R3 connected to a positive terminal S1+ of a speed input signal, a negative terminal resistor R4 connected to a negative terminal S1- of a speed input signal, an operational amplifier U0, a comparator connected to an output terminal of the operational amplifier U0, and a signal conversion circuit connected to the comparator, wherein the positive input pin of the operational amplifier U0 is connected to the positive terminal resistor R3, and the negative terminal S1- of the speed input signal is connected in parallel with a reference circuit and then connected to the negative input pin of the operational amplifier U0.

[0007] Optionally, the reference circuit includes a diode D1, a capacitor C1 and a capacitor C2 connected in parallel to the diode D1, a voltage regulator U1, capacitors C3 and C4 arranged in parallel, a reference voltage REF located between the capacitor C4 and the resistor R1, a resistor Rs arranged in parallel with the resistor R1, an operational amplifier U2, a resistor R2 and a capacitor C5.

[0008] Optionally, an input pin IN of the voltage regulator U1 is connected to one end of the capacitor C1, the capacitor C2 and the diode D1 respectively, and an output pin OUT of the voltage regulator U1 is connected to one end of the capacitor C3, the capacitor C4 and the resistor R1 respectively.

[0009] Optionally, the other ends of the capacitors C1 , C2 , C3 , and C4 and a ground terminal GND of the voltage regulator U1 are all grounded.

[0010] Optionally, the resistor Rs is a debugging resistor, and the resistor R1 and the resistor Rs are connected in parallel and then connected to the positive pin of the operational amplifier U2.

[0011] The utility model has the following beneficial technical effects:

[0012] The embodiment of the utility model provides an engine speed signal measurement circuit, including a positive terminal resistor R3 connected to the positive terminal S1+ of the speed input signal, a negative terminal resistor R4 connected to the negative terminal S1- of the speed input signal, an operational amplifier U0, a comparator connected to the output terminal of the operational amplifier U0, and a signal conversion circuit connected to the comparator, wherein the positive input pin of the operational amplifier U0 is connected to the positive terminal resistor R3, the negative terminal S1- of the speed input signal is connected to the negative input pin of the operational amplifier U0 after being connected in parallel with a reference circuit, and a reference circuit is added between the negative terminal S1- of the speed input signal and the negative input pin of the operational amplifier U0, on the one hand, the speed signal is raised to avoid interference signals during use affecting the conditioning accuracy of the conditioning circuit for the speed signal; on the other hand, the voltage division size of the reference circuit also determines the size of the threshold voltage, reducing the signal flipping of the frequency signal due to interference when the threshold voltage changes, thereby improving the measurement accuracy and solving the problem of large error in measuring the speed signal caused by interference generated during engine operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0014] Figure 1 This is a schematic diagram of the framework structure of an engine speed signal measurement circuit according to an embodiment of the utility model;

[0015] Figure 2 The figure is a schematic diagram of the structure of a reference circuit according to an embodiment of the utility model. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model will be further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0017] The following will be combined Figure 1 and Figure 2 An engine speed signal measurement circuit according to an embodiment of the utility model is described in detail.

[0018] refer to Figure 1 and Figure 2 As shown, an engine speed signal measurement circuit provided by an embodiment of the utility model increases a reference circuit between the negative terminal S1- of the speed input signal and the negative input pin of the operational amplifier U0. On the one hand, the speed signal is raised to prevent interference signals from affecting the conditioning accuracy of the speed signal by the conditioning circuit during use. On the other hand, the voltage divider size of the reference circuit also determines the size of the threshold voltage, thereby reducing the signal flipping of the frequency signal due to interference when the threshold voltage changes, thereby improving the measurement accuracy and solving the problem of large errors in the measured speed signal caused by interference generated during engine operation.

[0019] refer to Figure 1 and Figure 2 As shown, the utility model provides an engine speed signal measurement circuit including a positive resistor R3 connected to the positive terminal S1+ of the speed input signal, a negative resistor R4 connected to the negative terminal S1- of the speed input signal, an operational amplifier U0, a comparator connected to the output terminal of the operational amplifier U0, and a signal conversion circuit connected to the comparator, wherein the positive input pin of the operational amplifier U0 is connected to the positive resistor R3, and the negative terminal S1- of the speed input signal is connected to the negative input pin of the operational amplifier U0 after being connected in parallel with the reference circuit. In order to improve the accuracy of measuring the speed signal, a reference circuit is added between the negative terminal S1- of the speed input signal and the negative input pin of the operational amplifier U0, and a stable voltage signal is connected to the negative pole of the speed measurement signal input terminal. It can also be adjusted according to actual use requirements to obtain a signal to be processed with interference removed, thereby avoiding interference with subsequent conditioning circuits. An engine speed signal measurement circuit provided by an embodiment of the utility model, when testing the speed signal, the positive and negative differential inputs of the signal are connected to the operational amplifier U0, and the negative end of the operational amplifier U0 is grounded, the speed signal is impedance matched and amplified, and then a comparator is connected to convert the amplified sine wave into a square wave signal, and the square wave signal is converted into a voltage signal that meets the output requirements through a signal conversion circuit.

[0020] refer to Figure 1 and Figure 2 As shown, the reference circuit includes a diode D1, a capacitor C1 and a capacitor C2 connected to the diode D1 in parallel, a voltage regulator U1, capacitors C3 and C4 arranged in parallel, a reference voltage REF located between the capacitor C4 and the resistor R1, a resistor Rs arranged in parallel with the resistor R1, an operational amplifier U2, a resistor R2 and a capacitor C5. The input pin IN of the voltage regulator U1 is respectively connected to one end of the capacitor C1, the capacitor C2 and the diode D1, and the output pin OUT of the voltage regulator U1 is respectively connected to one end of the capacitor C3, the capacitor C4 and the resistor R1. The other ends of the capacitors C1, C2, C3 and C4 and the ground terminal GND of the voltage regulator U1 are all grounded. The resistor Rs is a debugging resistor, and the resistor R1 and the resistor Rs are connected in parallel to the positive pin of the operational amplifier U2.

[0021] refer to Figure 1 and Figure 2 As shown, the voltage regulator U1 generates a stable reference voltage REF. By adjusting the resistance of Rs, the reference voltage is set to a suitable voltage value. After being filtered by the voltage follower and RC, it is connected to the negative terminal of the speed signal input. The embodiment of the utility model avoids interference caused by mechanical movement during the actual operation of the engine by adding a reference voltage to the speed measurement circuit and connecting it to the negative terminal of the speed signal.

[0022] The embodiment of the utility model provides an engine speed signal measurement circuit, including a positive terminal resistor R3 connected to the positive terminal S1+ of the speed input signal, a negative terminal resistor R4 connected to the negative terminal S1- of the speed input signal, an operational amplifier U0, a comparator connected to the output terminal of the operational amplifier U0, and a signal conversion circuit connected to the comparator, wherein the positive input pin of the operational amplifier U0 is connected to the positive terminal resistor R3, the negative terminal S1- of the speed input signal is connected to the negative input pin of the operational amplifier U0 after being connected in parallel with a reference circuit, and a reference circuit is added between the negative terminal S1- of the speed input signal and the negative input pin of the operational amplifier U0, on the one hand, the speed signal is raised to avoid interference signals during use affecting the conditioning accuracy of the conditioning circuit for the speed signal; on the other hand, the voltage division size of the reference circuit also determines the size of the threshold voltage, reducing the signal flipping of the frequency signal due to interference when the threshold voltage changes, thereby improving the measurement accuracy and solving the problem of large error in measuring the speed signal caused by interference generated during engine operation.

[0023] Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present invention without departing from the spirit and scope of the embodiments of the present invention. Thus, if these modifications and variations of the embodiments of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. An engine speed signal measurement circuit, characterized in that: The engine speed signal measurement circuit includes a positive resistor R3 connected to the positive terminal S1+ of the speed input signal, a negative resistor R4 connected to the negative terminal S1- of the speed input signal, an operational amplifier U0, a comparator connected to the output terminal of the operational amplifier U0, and a signal conversion circuit connected to the comparator, wherein the positive input pin of the operational amplifier U0 is connected to the positive resistor R3, and the negative terminal S1- of the speed input signal is connected in parallel with a reference circuit and then connected to the negative input pin of the operational amplifier U0.

2. The engine speed signal measurement circuit according to claim 1, characterized in that: The reference circuit includes a diode D1, a capacitor C1 and a capacitor C2 connected in parallel to the diode D1, a voltage regulator U1, capacitors C3 and C4 arranged in parallel, a reference voltage REF located between the capacitor C4 and the resistor R1, a resistor Rs arranged in parallel to the resistor R1, an operational amplifier U2, a resistor R2 and a capacitor C5.

3. The engine speed signal measurement circuit according to claim 2, characterized in that: An input pin IN of the voltage regulator U1 is connected to one end of the capacitor C1 , the capacitor C2 , and the diode D1 , respectively. An output pin OUT of the voltage regulator U1 is connected to one end of the capacitor C3 , the capacitor C4 , and the resistor R1 , respectively.

4. The engine speed signal measurement circuit according to claim 3, characterized in that: The other ends of the capacitors C1 , C2 , C3 , and C4 and a ground terminal GND of the voltage regulator U1 are all grounded.

5. The engine speed signal measurement circuit according to claim 3, characterized in that: The resistor Rs is a debugging resistor. The resistors R1 and Rs are connected in parallel and then connected to the positive pin of the operational amplifier U2.

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