Engine rotating speed acquisition circuit

Abstract

The utility model provides an engine rotating speed acquisition circuit, which comprises a voltage acquisition module, a voltage dynamic output module, a comparator and a processor, the input end of the voltage acquisition module is externally connected with a rotating speed signal of an engine, and the voltage acquisition module outputs a voltage signal acquired from the rotating speed signal to the processor; the processor dynamically processes the voltage signal obtained from the voltage acquisition module and then outputs the voltage signal to the voltage dynamic output module; one input end of the comparator is externally connected with a rotating speed signal of an engine, and the other input end of the comparator is electrically connected with the output end of the voltage dynamic output module; and the output end of the comparator is electrically connected with the processor. The engine rotating speed acquisition circuit is high in anti-noise performance, can improve the engine rotating speed acquisition precision, and is wider in adaptive voltage variation range.

Description

Technical Field

[0001] The invention relates to the technical field of aircraft onboard electronic equipment, and in particular to an engine speed acquisition circuit. Background Art

[0002] With the development of airborne electronic equipment technology, equipment functions are becoming more and more complex, equipment power is increasing, but equipment size is required to be smaller and smaller. This places higher and higher requirements on the anti-interference ability of airborne electronic equipment, which is already in a harsh airborne environment.

[0003] At present, the speed of civil aircraft engines is mostly collected by electromagnetic sensors. The output signal of this sensor is similar to a sine wave and contains various noises. Generally, this signal is converted into a PWM signal with a proportional frequency. The processor collects the signal frequency to obtain the speed. Among them, the conditioning circuit generally uses a comparator with a hysteresis loop. Since the voltage span of the collected signal is large and contains a lot of noise, it is difficult to select the reference voltage of the comparator. If the selection is inappropriate, it is easy to reduce the anti-interference ability of the circuit and the frequency test accuracy.

[0004] The main defects of the airborne multi-function display in the prior art are as follows:

[0005] Since the sensor contains various noises generated by the engine, and the signal amplitude increases with the increase of frequency, at low frequency, the sensor signal amplitude is about 0.4V-1V, and the noise is relatively small at this time; at high frequency, the sensor signal amplitude can exceed 50V, and the noise is relatively large at this time. If the reference voltage of the comparator in the acquisition circuit is too large, it is easy to cause signal leakage at low frequency, and if it is too small, the noise is large at high frequency, which is easy to cause misjudgment. As a result, the accuracy of engine speed acquisition is reduced.

[0006] The market urgently needs to develop an engine speed acquisition circuit that can optimize the engine speed signal, has high anti-noise performance, and can improve the accuracy of engine speed acquisition. Summary of the invention

[0007] In order to solve the problems in the prior art, the utility model provides an engine speed acquisition circuit which can optimize the engine speed signal, has high anti-noise performance, can improve the engine speed acquisition accuracy, and can adapt to a wider voltage variation range.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] An engine speed acquisition circuit includes a voltage acquisition module, a voltage dynamic output module, a comparator, and a processor;

[0010] The input end of the voltage acquisition module is externally connected to the engine speed signal, and the voltage acquisition module outputs the voltage signal collected from the speed signal to the processor; the processor dynamically processes the voltage signal obtained from the voltage acquisition module and outputs it to the voltage dynamic output module; one input end of the comparator is externally connected to the engine speed signal, and the other input end of the comparator is electrically connected to the output end of the voltage dynamic output module; the output end of the comparator is electrically connected to the processor.

[0011] In the engine speed acquisition circuit of this architecture, the voltage acquisition module acquires the voltage signal in the engine speed signal and sends it to the processor, which outputs it to the comparator through the voltage dynamic output module; the other input end of the comparator obtains the dynamic signal reference value from the voltage dynamic output module; one input end of the comparator obtains the current signal value from the engine speed signal; the comparator compares the current signal value directly obtained from the engine speed signal with the signal reference value obtained from the voltage dynamic output module to generate a PWM signal, which the comparator inputs to the processor, thereby completing the dynamic comparison acquisition of the engine speed. Compared with the traditional comparator whose reference value is a fixed value, the comparator of the acquisition circuit architecture of the utility model uses the signal acquired last time as the reference value for the current acquisition and performs dynamic comparison, so that the acquired engine speed is more accurate and has stronger anti-interference ability, especially compared with the traditional comparator whose reference value is a fixed value, it can adapt to a wider range of voltage changes and has stronger adaptability.

[0012] A preferred technical solution further includes a signal differential amplifier; the engine speed signal is output to the input end of the voltage acquisition module and an input end of the comparator after passing through the signal differential amplifier.

[0013] A preferred technical solution further includes a low-pass filter, and the engine speed signal is filtered by the low-pass filter and then input into the signal differential amplifier.

[0014] After the low-pass filter removes the high-frequency noise of the speed signal, the speed signal passes through the signal differential amplifier, which increases the signal voltage while removing the common-mode interference of the speed signal.

[0015] A preferred technical solution further includes an isolation circuit, and the engine speed signal is input into the low-pass filter after passing through the isolation circuit.

[0016] The speed signal passes through the isolation circuit, which isolates the engine sensor from the acquisition circuit to avoid mutual influence.

[0017] A preferred technical solution further includes a protection module, and the engine speed signal is input into the isolation circuit after passing through the protection module.

[0018] The speed signal first passes through the protection module to realize the electromagnetic compatibility protection function of the circuit.

[0019] Compared with the engine speed acquisition circuit in the prior art, the utility model has the following beneficial effects:

[0020] 1. The processor obtains the input signal voltage through the voltage acquisition module, and then outputs the last voltage signal through the voltage dynamic output module, dynamically adjusts the reference voltage signal of the comparator, and adapts to the different voltage ranges of the speed signal, thereby optimizing the high voltage and high noise problem and improving the engine speed acquisition accuracy.

[0021] 2. Optimize the noise processing of the acquisition circuit, increase the anti-interference ability of the acquisition circuit, and improve the accuracy of engine speed acquisition. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the principle of an engine speed acquisition circuit in Embodiment 1 of the present invention;

[0023] Figure 2 This is a schematic diagram of the principle of an engine speed acquisition circuit in Example 2 of the present invention. DETAILED DESCRIPTION

[0024] Example 1

[0025] like Figure 1 As shown, an engine speed acquisition circuit includes a voltage acquisition module, a voltage dynamic output module, a comparator, and a processor;

[0026] The input end of the voltage acquisition module is externally connected to the engine speed signal, and the voltage acquisition module outputs the voltage signal collected from the speed signal to the processor; the processor dynamically processes the voltage signal obtained from the voltage acquisition module and outputs it to the voltage dynamic output module; one input end of the comparator is externally connected to the engine speed signal, and the other input end of the comparator is electrically connected to the output end of the voltage dynamic output module; the output end of the comparator is electrically connected to the processor.

[0027] The working principle of the engine speed acquisition circuit of the present embodiment 1 is as follows: the voltage acquisition module acquires the voltage signal from the engine speed signal and inputs it to the processor, the processor sends the voltage signal value to the comparator through the voltage dynamic output module, the comparator uses the voltage signal obtained by the voltage dynamic output module as a reference value (there is a time difference between the reference value and the signal obtained by the comparator directly from the engine speed signal), compares it with the signal value obtained by the comparator directly from the engine speed signal, outputs a PWM signal to the processor, and the processor obtains the final engine speed based on the PWM signal. Thus, the reference voltage signal of the comparator is dynamically adjusted to adapt to different voltage ranges of the speed signal, thereby optimizing the high voltage and high noise problem and improving the accuracy of engine speed acquisition.

[0028] Example 2

[0029] like Figure 2 As shown, an engine speed acquisition circuit includes a protection module, an isolation circuit, a low-pass filter, a signal differential amplifier, a voltage acquisition module, a voltage dynamic output module, a comparator, and a processor;

[0030] The input end of the protection module is externally connected to the engine speed signal, and the output end of the protection module is electrically connected to the input end of the isolation circuit; the output end of the isolation circuit is electrically connected to the input end of the low-pass filter; the output end of the low-pass filter is electrically connected to the input end of the signal differential amplifier, the output end of the signal differential amplifier is electrically connected to the input end of the voltage acquisition module, and the output end of the signal differential amplifier is also electrically connected to an input end of the comparator; the input end of the voltage acquisition module is externally connected to the engine speed signal, and the voltage acquisition module outputs the voltage signal collected from the speed signal to the processor; the processor dynamically processes the voltage signal obtained from the voltage acquisition module and outputs it to the voltage dynamic output module; one input end of the comparator is externally connected to the engine speed signal, and the other input end of the comparator is electrically connected to the output end of the voltage dynamic output module; the output end of the comparator is electrically connected to the processor.

[0031] The working principle of an engine speed acquisition circuit in this embodiment 2 is as follows:

[0032] The speed signal first passes through the protection module to realize the electromagnetic compatibility protection function of the circuit. Then, the speed signal passes through the isolation circuit, which isolates the engine sensor from the acquisition circuit to avoid mutual influence. After the low-pass filter removes the high-frequency noise of the speed signal, the speed signal passes through the signal differential amplifier to increase the signal voltage while removing the common-mode interference of the speed signal. Finally, the processor obtains the input signal voltage through the voltage acquisition module, and then outputs the voltage signal through the voltage dynamic output module, dynamically adjusts the comparator reference voltage, and adapts to the different voltage ranges of the speed signal, thereby optimizing the anti-noise performance of the speed signal.

[0033] The other parts of the structure of the present embodiment 2 are the same as those of the aforementioned embodiment 1, and thus will not be described in detail here.

[0034] The above are only preferred application embodiments of the present invention and are not intended to limit the present invention. It should be pointed out that any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An engine speed acquisition circuit, characterized in that: It includes a voltage acquisition module, a voltage dynamic output module, a comparator, and a processor; The input end of the voltage acquisition module is externally connected to the speed signal of the engine, and the voltage acquisition module outputs the voltage signal collected from the speed signal to the processor; The processor dynamically processes the voltage signal obtained from the voltage acquisition module and outputs it to the voltage dynamic output module; one input end of the comparator is externally connected to the engine speed signal, and the other input end of the comparator is electrically connected to the output end of the voltage dynamic output module; the output end of the comparator is electrically connected to the processor.

2. The engine speed acquisition circuit according to claim 1, characterized in that: It also includes a signal differential amplifier; the engine speed signal is output to the input end of the voltage acquisition module and an input end of the comparator after passing through the signal differential amplifier.

3. The engine speed acquisition circuit according to claim 2, characterized in that: It also includes a low-pass filter, and the engine speed signal is filtered by the low-pass filter and then input into the signal differential amplifier.

4. The engine speed acquisition circuit according to claim 3 is characterized in that: It also includes an isolation circuit, and the engine speed signal is input into the low-pass filter after passing through the isolation circuit.

5. The engine speed acquisition circuit according to claim 4, characterized in that: It also includes a protection module, and the engine speed signal is input into the isolation circuit after passing through the protection module.

Images