CN214893474U

CN214893474U - Signal processing equipment of turbine fuel mass flow meter

Info

Publication number: CN214893474U
Application number: CN202120789829.XU
Authority: CN
Inventors: 侯小宇
Original assignee: China Civil Aviation Airworthiness Certification Center
Current assignee: China Civil Aviation Airworthiness Certification Center
Priority date: 2021-04-16
Filing date: 2021-04-16
Publication date: 2021-11-26
Anticipated expiration: 2031-04-16

Abstract

The embodiment of the utility model discloses a signal processing device of a turbine fuel mass flowmeter, which comprises an analog signal processing module and a digital signal processing module; the digital signal processing module comprises a digital adjustable low-pass filter, a digital zero-crossing judger, a high-speed digital clock and a processor; the output end of the analog signal processing module is connected with the input end of the digital adjustable low-pass filter; the output end of the digital adjustable low-pass filter is connected with the input end of the digital zero-crossing judger; the output end of the digital zero-crossing judger is connected with the input end of the high-speed digital clock; and the output end of the high-speed digital clock is connected with the processor. The signal processing equipment can be suitable for calculating the fuel mass flow in the prior art, and has simple structure and low price.

Description

Signal processing equipment of turbine fuel mass flow meter

Technical Field

The utility model relates to an aeroengine's control and fuel oil system technical field, concretely relates to turbine fuel mass flow meter's signal processing equipment.

Background

Fuel consumption monitoring of aircraft engines is an important part of aircraft engine operation monitoring. On one hand, the fuel consumption is an important index for measuring the performance of the aircraft engine, and has important significance for evaluating the task capacity and the running state of the aircraft engine; on the other hand, the fuel consumption monitoring is an important means for diagnosing the fault of the fuel system, and the fuel supply abnormity of the fuel system can be diagnosed by comparing the actual fuel consumption with the given quantity difference of the fuel system. Modern aircraft engines are equipped with turbine fuel turbine mass flow meter sensors.

The turbine fuel mass flow meter sensor generates two pulse signals when fuel flows through the sensor, the fuel mass flow is determined by measuring the time difference of the two pulse signals, and the fuel mass flow is in direct proportion to the time difference of the two pulse signals. The pulse signals generated by the turbine fuel mass flow meter belong to low-frequency weak pulse signals, the noise of the signals is large, the signals are easily interfered, the frequency range of the signals is usually 2-10Hz, and the amplitude range of the signals is usually-100-400 mv.

In the actual operation process of the aircraft engine, the fuel mass flow changes greatly, the minimum is 100-200 kg/h, the maximum is 5000-9000 kg/h, the corresponding signal amplitude changes greatly, the minimum is-5-15 mv, the maximum is-100-400 mv, the small flow is influenced by signal noise, the situation that the measurement cannot be carried out or large errors easily occur, the large errors easily occur due to the influence of the signal noise at the large flow, the maximum error is more than 100kg/h, and the evaluation of the operation state of the aircraft engine and the diagnosis of fuel supply faults of a fuel system are influenced.

The common processing method is to perform analog conditioning on an input signal, generate an I/O pulse level through amplitude comparison, calculate the time difference of the I/O pulse level by adopting a digital method, and finally convert the time difference of the pulse level into fuel mass flow. The method has the advantages of simple design and easy realization; the method has the disadvantages that the de-noising capability of analog filtering is limited, so that signals are easily interfered, and the pulse signals are converted into pulse levels through threshold judgment to perform falling edge judgment, so that the precision of signal processing is not high, and particularly, under the conditions of small flow and small signal amplitude, large errors exist, and the measurement precision requirement can not be met.

At present, in order to improve the measurement accuracy and the anti-interference capability of a fuel mass flow signal, the applicant researches a calculation method: and acquiring two paths of input signals, processing the input signals to obtain a time difference signal, and obtaining the fuel mass flow according to the time difference signal. However, no improved hardware device has been provided for adapting the above-described calculation method.

SUMMERY OF THE UTILITY MODEL

An object of the embodiment of the utility model is to provide a turbine fuel mass flow meter's signal processing equipment, this signal processing equipment simple structure, low price.

Therefore, the utility model provides a technical scheme as follows:

the signal processing equipment of the turbine fuel mass flowmeter comprises an analog signal processing module and a digital signal processing module; the digital signal processing module comprises a digital adjustable low-pass filter, a digital zero-crossing judger, a high-speed digital clock and a processor;

the output end of the analog signal processing module is connected with the input end of the digital adjustable low-pass filter;

the output end of the digital adjustable low-pass filter is connected with the input end of the digital zero-crossing judger;

the output end of the digital zero-crossing judger is connected with the input end of the high-speed digital clock;

and the output end of the high-speed digital clock is connected with the processor.

As a specific embodiment of the present application, the analog signal processing module includes:

the second-order analog low-pass filter receives an input analog signal 1 and an input analog signal 2 and carries out analog filtering processing on the analog signals;

the amplifier is used for amplifying and conditioning the analog signal 1 and the analog signal 2 after analog filtering;

the sampler is used for carrying out rapid AD sampling on the amplified and conditioned analog signal 1 and analog signal 2 to obtain a digital signal 1 and a digital signal 2; wherein the sampling frequency is more than 2 times of the-40 dB frequency point of the analog filter.

As a preferred embodiment of the present application, the digitally tunable low-pass filter comprises three second-order IIR filters.

The utility model discloses a signal processing device of turbine fuel mass flowmeter, including analog signal processing module and digital signal processing module, and the digital signal processing module includes digital adjustable low pass filter, digital zero crossing judger, high-speed digital clock and treater; the signal processing equipment can be suitable for calculating the fuel mass flow in the prior art, and has simple structure and low price.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the technical solutions in the prior art will be briefly described below. Throughout the drawings, like elements or portions are generally identified by like reference numerals. In the drawings, elements or portions are not necessarily drawn to scale.

FIG. 1 is a schematic diagram of high precision processing of turbine fuel mass flow meter signals;

fig. 2 is a diagram of an IIR filtering calculation process.

The symbols in the drawings are as follows:

analog low pass filtering

Analog signal amplification

Analog to digital conversion

Digitally tunable low pass filtering

Digital zero crossing determination

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and therefore are only examples, and the protection scope of the present invention is not limited thereby.

It is to be noted that unless otherwise specified, technical or scientific terms used herein shall have the ordinary meaning as understood by those skilled in the art to which the present invention belongs.

The utility model provides a turbine fuel mass flow meter's signal processing equipment mainly includes analog signal processing module and digital signal processing module.

Referring to fig. 1, the analog signal processing module mainly includes:

the second-order analog low-pass filter receives an input analog signal 1 and an input analog signal 2 and carries out analog filtering processing on the analog signals; the second-order analog low-pass filter can be of the type of EMIF10-LCD03F3, but is not limited to the type;

the amplifier is used for amplifying and conditioning the analog signal 1 and the analog signal 2 after analog filtering; the amplifier can be a common operational amplifier or a low-power consumption amplifier of HJ322A type;

the sampler is used for carrying out rapid AD sampling on the amplified and conditioned analog signal 1 and analog signal 2 to obtain a digital signal 1 and a digital signal 2; wherein the sampling frequency is more than 2 times of the-40 dB frequency point of the analog filter. The sampler can select an AD series data acquisition device of AD 2014-ICJ.

The digital signal processing module comprises a digital adjustable low-pass filter, a digital zero-crossing judger, a high-speed digital clock and a processor;

and the output end of the high-speed digital clock is connected with the processor. The processor may select the stm32f103 chip.

Preferably, in this embodiment, the digitally tunable low-pass filter includes three second-order IIR filters, and the specific filtering calculation process thereof can refer to fig. 2.

Referring to fig. 1 again, the working principle of the signal processing apparatus provided by the present invention is as follows:

(1) and performing second-order analog low-pass filtering processing on the input Start pulse signal and Stop pulse signal to reduce the noise level of the signals.

(2) And amplifying and conditioning the Start pulse signal and the Stop pulse signal after analog filtering respectively to enable the signals to be matched with the voltage of a subsequent processing circuit.

(3) Respectively carrying out rapid AD acquisition on the amplified and conditioned Start and Stop pulse signals to obtain a digital signal 1 and a digital signal 2; wherein the sampling rate is more than 2 times of the-40 dB frequency point of the analog filter.

(4) And three second-order IIR filters are adopted to respectively carry out filtering processing on the digital signal 1 and the digital signal 2 so as to reduce the noise of the digital signal 1 and the digital signal 2.

(5) And performing falling edge zero-crossing judgment processing on the filtered digital signal 1 and the filtered digital signal 2 by adopting a waveform zero-crossing identification method to obtain a zero-crossing signal 1 and a zero-crossing signal 2.

(6) And calculating the time difference of the zero-crossing points of the zero-crossing signal 1 and the zero-crossing signal 2 by adopting a high-speed digital clock.

(7) And converting the time difference into the fuel mass flow rate by combining the characteristics of the turbine fuel mass flow meter. The time difference between zero-crossing points of the zero-crossing signal 1 and the zero-crossing signal 2 is in direct proportion to the fuel mass flow.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the scope of the embodiments of the present invention, and are intended to be covered by the claims and the specification.

Claims

1. The signal processing equipment of the turbine fuel mass flowmeter is characterized by comprising an analog signal processing module and a digital signal processing module; the digital signal processing module comprises a digital adjustable low-pass filter, a digital zero-crossing judger, a high-speed digital clock and a processor;

2. The signal processing device of claim 1, wherein the analog signal processing module comprises:

3. A signal processing device according to claim 1 or 2, wherein the digitally tunable low-pass filter comprises three second-order IIR filters.