Generator oil level detection method based on analog quantity acquisition

Abstract

The invention relates to the technical field of oil level detection, in particular to a generator oil level detection method based on analog quantity acquisition, which comprises the following steps: acquiring the theoretical oil quantity of a generator after a preset first duration; excitation is added when the permanent magnet machine has a frequency fault and a wheel load signal is in a ground state; excitation is removed, and the end oil mass of oil mass detection is obtained; and the current actual oil quantity of the generator after the preset first duration is obtained, and the oil level state of the generator is determined. When the generator is in the oil level warning state, generator low-oil-quantity warning is given out in time, the generator is prevented from being damaged, and execution of a flight task is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of oil level detection, and in particular to a generator oil level detection method based on analog quantity acquisition. Background Art

[0002] In aviation power generation systems, whether the generator oil level signal can be correctly collected is crucial to aviation safety. At present, most aviation power generation systems use discrete oil level detection sensors for oil level detection. The implementation principle is to pre-set one or two sensors at different heights inside the generator. When the lubricating oil level in the generator tank is lower than the lower limit (the distance from the oil level to the installation surface of the oil level signal), the sensor will be detected. mm, the oil level signal device reports a switch signal, transmits the switch signal to the generator controller, and reports a low oil level alarm after a delay judgment; when the lubricating oil level in the generator tank is higher than the upper limit (the distance from the oil level to the installation surface of the oil level signal device) 110 When the oil level signal is on, the oil level annunciator reports a switch signal, which is transmitted to the generator controller, and after a delay judgment, it reports that the oil level is normal.

[0003] The weight of the discrete oil level detection sensor is about 500g, and the outer dimensions are ∅54mm×119mm. According to actual usage, the current discrete oil level detection sensor has the characteristics of large size, large weight, large oil level detection error, and high failure rate. The specific disadvantages are as follows: The installation position and installation method of the discrete oil level detection sensor will affect its measurement accuracy. Due to the volume and weight limitations of the discrete oil level sensor, the installation position and installation method of the discrete oil level detection sensor will affect its measurement accuracy. Due to the volume and weight limitations of the discrete oil level sensor, compared with the analog oil level detection sensor in this article, the discrete oil level sensor has a larger installation measurement error; the discrete oil level detection sensor will cause its performance to deteriorate when it works for a long time and lacks necessary maintenance, thereby increasing the failure rate.

[0004] In addition to the above-mentioned defects of discrete oil level detection sensors, discrete oil level collection methods also have inherent defects, such as: 1. Data discontinuity: Discrete collection methods usually measure within a specific time interval and may not be able to reflect changes in oil volume in real time, resulting in data that is not timely and accurate enough; 2. Sampling deviation: Due to the selection of sampling time points, changes in oil volume at certain critical moments may not be captured, resulting in data deviation and affecting overall analysis and decision-making; 3. Slow response speed: When a rapid response is required, discrete collection methods may not be able to meet the needs of real-time monitoring, especially when the oil volume changes rapidly; 4. Complex data processing: Since the collected data is discrete, additional algorithms may be required to interpolate or estimate the data, which increases the complexity and uncertainty of data processing; 5. Environmental impact: External environmental factors (such as temperature, pressure, etc.) may affect the accuracy of discrete collection, especially under extreme conditions; 6. Unable to capture short-term fluctuations: For some short-term oil volume fluctuations, discrete collection methods may completely ignore them, resulting in misjudgment of the actual situation.

[0005] Therefore, it is necessary to provide a generator oil level detection method based on analog quantity acquisition to solve the above problems. Summary of the invention

[0006] The invention provides a generator oil level detection method based on analog quantity acquisition to solve the existing problems.

[0007] A generator oil level detection method based on analog quantity acquisition of the present invention adopts the following technical scheme, including: The real-time oil volume of the generator during power-on self-test is used as the initial real-time oil volume, and the theoretical oil volume of the generator after a preset first time period is obtained according to the initial real-time oil volume; When the permanent magnet machine frequency fails and the wheel load signal is in the ground state, the generator oil level detection excitation signal is set to the plus excitation state; When the generator low oil level detection delay reaches a preset first time length, the generator oil level detection excitation signal is set to a de-excitation state, and the current real-time oil level of the generator is set as the end oil level of the oil level detection; According to the initial real-time oil quantity and the final oil quantity, obtaining the current actual oil quantity of the generator after a preset first time period; The oil level status of the generator is obtained based on the theoretical oil volume and the current actual oil volume.

[0008] Preferably, the expression of the theoretical oil volume of the generator after the preset first time period is:

[0009] In the formula, Indicates the theoretical oil volume of the generator after the preset first time period; Indicates the initial real-time oil volume.

[0010] Preferably, when the permanent magnet machine frequency meets the preset frequency range and continues within the frequency range for a preset second time period, the permanent magnet machine frequency is faulty; when the permanent magnet machine frequency does not meet the preset frequency range, the permanent magnet machine frequency is normal.

[0011] Preferably, the preset frequency range is less than or equal to 100 Hz, and the preset second time length is 5 s.

[0012] Preferably, when the aircraft is on the ground and the generator is not rotating in a stable oil level state, the wheel load signal is in a ground state.

[0013] Preferably, the difference between the final oil level of the oil level detection and the initial real-time oil level of the oil level detection is used as the current actual oil level of the generator after the preset first time period.

[0014] Preferably, the preset first duration is 30 seconds.

[0015] Preferably, the steps of obtaining the oil level status of the generator are: When the current actual oil volume is greater than or equal to the theoretical oil volume, the generator is in oil level alarm state; When the current actual oil volume is less than the theoretical oil volume, the generator is in a normal oil level state.

[0016] Preferably, the method further comprises: placing an analog oil level detection sensor for detecting the oil level in the generator parallel to the oil level.

[0017] The beneficial effects of the present invention are: When the aircraft is on the ground and the generator is stationary, the power supply system enters a real-time control state. After the generator controller is powered on, the generator oil level detection circuit is energized for detection, thereby obtaining the generator oil level status based on the theoretical oil level of the generator after a preset first period of time and the current actual oil level. When the generator is in an oil level warning state, a generator low oil level warning is issued in time to prevent damage to the generator and ensure the execution of the flight mission. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art 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 paying creative work.

[0019] Figure 1 It is a flow chart of an embodiment of a generator oil level detection method based on analog quantity acquisition of the present invention; Figure 2It is a detailed flow chart of a generator oil level detection method based on analog quantity acquisition in an embodiment of the present invention; Figure 3 is a schematic diagram of a generator low oil level detection circuit in an embodiment of the present invention; Figure 4 It is a curve diagram of the oil temperature signal value collected after the low oil level detection circuit of the generator in the air and oil in the embodiment of the present invention is stimulated. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] An embodiment of a generator oil level detection method based on analog quantity acquisition of the present invention, in this embodiment, the generator oil level detection is performed in the software real-time control, when the generator controller enters the real-time control state after power-on initialization, it detects that the wheel load signal is on the ground and the permanent magnet machine frequency is less than or equal to 100Hz and lasts for 5s, it enters the generator low oil level detection, such as Figure 1 and Figure 2 As shown, this embodiment specifically includes: S1, obtaining the theoretical oil volume of the generator after a preset first time period; The real-time oil volume of the generator during the power-on self-test is taken as the initial real-time oil volume, and the theoretical oil volume of the generator after the preset first time period is obtained according to the initial real-time oil volume. In this embodiment, the preset first time period is 30 seconds. Since the growth values ​​of the sensitive resistor in the air and the oil are different, a corresponding relationship between the initial value of the sensitive resistor and the difference value of the sensitive resistor after 30 seconds of excitation can be established, as shown in the following formula (1). The growth values ​​of the sensitive resistors of the oil and the air are collected. After power-on, the theoretical value of the difference value of the sensitive resistor after 30 seconds of excitation can be obtained by the sensitive resistor value collected during de-excitation, that is, the theoretical oil volume of the generator after the preset first time period is: (1) In the formula, Indicates the theoretical oil volume of the generator after the preset first time period; Indicates the initial real-time oil level; judge whether the sensitive resistor is in oil or air through the actual values ​​after de-excitation for 30s and after excitation for 30s. When the sensitive resistor is in the air, the generator controller reports the low oil level alarm of the generator through communication.

[0022] S2, add excitation when the permanent magnet machine frequency fails and the wheel load signal is in the ground state; When the permanent magnet machine frequency fails and the wheel load signal is in the ground state (the aircraft is on the ground and the generator is not rotating), the generator oil quantity detection excitation signal is set to the plus excitation state, that is, when the real-time collected permanent magnet machine frequency is less than or equal to 100Hz, the permanent magnet machine frequency is set to be too low. The fault flag is set to be a fault. At this time, if the low frequency reaches the preset second duration of 5.0s, the permanent magnet machine is a low frequency fault; if the permanent magnet machine frequency is greater than 100Hz, the permanent magnet machine frequency is normal. At this time, when the oil level is stable and detectable, the generator oil quantity detection excitation signal is set to the plus excitation state, and the initial oil quantity of the oil quantity detection is set to the real-time collected generator oil quantity, and the generator low oil quantity delay is started for the preset first duration of 30.0s for detection.

[0023] S3, de-energizing, and obtaining the end oil volume of the oil volume detection; When the generator low oil level detection delay reaches the preset first time length, the generator oil level detection excitation signal is set to the de-excitation state, and the current real-time oil level of the generator is set as the end oil level of the oil level detection. In this embodiment, the preset first time length is 30.0s. When the generator low oil level detection delay reaches the preset first time length of 30.0s, the generator oil level detection excitation signal is set to the de-excitation state, and the current real-time oil level of the generator currently detected is used as the end oil level of the oil level detection.

[0024] S4, obtaining the current actual oil volume of the generator after a preset first time period, and determining the oil level state of the generator; According to the initial real-time oil volume and the final oil volume, the current actual oil volume of the generator after the preset first time period is obtained; according to the size of the theoretical oil volume and the current actual oil volume, the oil level status of the generator is obtained.

[0025] In this embodiment, the difference between the end oil level of the oil level detection and the initial real-time oil level of the oil level detection is used as the current actual oil level of the generator after the preset first time period. When the current actual oil level is greater than or equal to the theoretical oil level, it is considered that the sensitive resistor is in the air, and the generator is determined to be in the oil level alarm state; when the current actual oil level is less than the theoretical oil level, the generator is in the normal oil level state.

[0026] In this embodiment, an analog oil level detection sensor (using a thermistor) for detecting the oil level is placed in the generator parallel to the oil surface, rather than perpendicular to the oil surface, so as to minimize the contact time between the oil level and the sensor, thereby facilitating accurate measurement of whether the oil level is low. After completing the low oil level detection, the generator oil level detection excitation signal is de-excited, and the generator oil level status at this time is reported through communication.

[0027] The following is combined with Figure 3-4 This embodiment is described: The generator low oil detection circuit of this embodiment is shown in FIG. Figure 3 Specifically, the circuit includes: a relay controlled circuit, a filter circuit, a voltage stabilizing circuit and a voltage following circuit. When the generator controller is working normally, it analyzes whether the oil quantity detection conditions are met according to the oil quantity detection judgment logic. If so, the CPLD device I / O port outputs a level, which is passed through the JS164245 level conversion chip and Darlington array to close the relay coil. The thermistor sampling circuit monitors the oil temperature signal in real time.

[0028] Based on the characteristic that thermistors have different temperature rise values ​​in different media when the heat generation is the same, the oil temperature difference is used to determine which medium the thermistor is in after 30 seconds. The difference between the de-excitation and the excitation after a period of time takes into account the different growth of sensitive resistors after excitation at different temperatures. Therefore, at the temperature [-20,100]℃ where the airborne equipment can be used normally, a large number of experiments are conducted to obtain the oil temperature signal value collected after the generator low oil detection circuit is excited in air and oil and plot it into a curve (see Figure 4 ), the horizontal axis is time, the unit is 100ms, and the vertical axis is the oil temperature signal value collected by the circuit. According to the curve, the oil temperature signal value collected by the circuit after the low oil detection circuit of the generator in the air and oil at different temperatures is excited shows a rapid rise and tends to be flat after 25s. Considering the error of the acquisition, the circuit is selected to be excited for 30s and then read the difference between the de-excitation and the excitation for a period of time.

[0029] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A generator oil level detection method based on analog quantity acquisition, characterized in that: include: The real-time oil volume of the generator during power-on self-test is used as the initial real-time oil volume, and the theoretical oil volume of the generator after a preset first time period is obtained according to the initial real-time oil volume; When the permanent magnet machine frequency fails and the wheel load signal is in the ground state, the generator oil level detection excitation signal is set to the plus excitation state; When the generator low oil level detection delay reaches a preset first time length, the generator oil level detection excitation signal is set to a de-excitation state, and the current real-time oil level of the generator is set as the end oil level of the oil level detection; According to the initial real-time oil quantity and the final oil quantity, obtaining the current actual oil quantity of the generator after a preset first time period; The oil level status of the generator is obtained based on the theoretical oil volume and the current actual oil volume.

2. The generator oil level detection method based on analog quantity acquisition according to claim 1 is characterized in that: The expression of the theoretical oil volume of the generator after the preset first time period is: In the formula, Indicates the theoretical oil volume of the generator after the preset first time period; Indicates the initial real-time oil volume.

3. The generator oil level detection method based on analog quantity acquisition according to claim 1 is characterized in that: When the permanent magnet machine frequency meets the preset frequency range and lasts within the frequency range for a preset second time period, the permanent magnet machine frequency is faulty; when the permanent magnet machine frequency does not meet the preset frequency range, the permanent magnet machine frequency is normal.

4. The generator oil level detection method based on analog quantity acquisition according to claim 3 is characterized in that: The preset frequency range is less than or equal to 100 Hz, and the preset second time length is 5 seconds.

5. The generator oil level detection method based on analog quantity acquisition according to claim 1 is characterized in that: When the aircraft is on the ground and the generator is not rotating and the oil level is stable, the wheel load signal is in the ground state.

6. The generator oil level detection method based on analog quantity acquisition according to claim 1 is characterized in that: The difference between the final oil quantity of the oil quantity detection and the initial real-time oil quantity of the oil quantity detection is used as the current actual oil quantity of the generator after the preset first time period.

7. The generator oil level detection method based on analog quantity acquisition according to claim 1 is characterized in that: The default first duration is 30s.

8. The generator oil level detection method based on analog quantity acquisition according to claim 1 is characterized in that: The steps to obtain the oil level status of the generator are: When the current actual oil volume is greater than or equal to the theoretical oil volume, the generator is in oil level alarm state; When the current actual oil volume is less than the theoretical oil volume, the generator is in a normal oil level state.

9. The generator oil level detection method based on analog quantity acquisition according to claim 1 is characterized in that: Also includes: An analog oil level detection sensor for detecting the oil level is placed in the generator parallel to the oil level.

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