A method and system for open circuit detection of a reluctance type rotational speed signal

Abstract

The present application relates to the field of aviation turboprop engine, and provides a kind of reluctance type rotational speed signal open circuit detection method and system, comprising: rotational speed signal acquisition conditioning circuit, DC level lifting circuit, integral circuit, negative feedback saturation prevention circuit and open circuit detection circuit, hardware integrator is used, only to ultra-low frequency signal amplification, low frequency and high frequency signal are filtered and attenuated.Can meet both sensor open circuit fault detection, meet low frequency signal and high frequency signal frequency detection, while ensuring that the sensor output frequency and amplitude are not triggered open circuit fault when normal work.Solve the technical problems that the rotational speed signal frequency is higher in the prior art, and the open circuit detection function under low rotational speed signal cannot be realized.

Description

Technical Field

[0001] This invention relates to the field of aero-engine turboprop technology, and in particular to a magnetoresistive speed signal open-circuit detection method and system. Background Technology

[0002] In the health management system of an aero-engine, engine speed is an extremely important parameter for evaluating engine performance, monitoring the test process, and monitoring functions. It is also a commonly used controlled variable for the engine. Measuring engine speed is frequently involved, and the control system requires a high degree of accuracy in speed measurement. Accurate and real-time measurement of engine speed is crucial for ensuring the normal operation and safety of the engine.

[0003] Regarding speed signal acquisition and open-circuit detection, existing methods include "An Engine Speed ​​Measurement Circuit and Method," which describes a high-precision speed signal detection circuit and method, but does not describe the open-circuit detection fault circuit and detection method; and "A Magnetoresistive Speed ​​Signal Acquisition Method and System with Open-Circuit Detection," which describes a circuit design method with open-circuit detection function. The main principle of this method is to use a voltage boosting circuit to provide different voltage boosting effects to the subsequent circuit when it is open-circuited and when it is not open-circuited, so as to identify the open-circuit state. In the non-open-circuit state, the amplitude of the sinusoidal voltage signal after being filtered by the low-pass filter of R4 and C1 is less than the comparison voltage of the comparator. Therefore, the speed signal frequency is required to be relatively high, which cannot realize the open-circuit detection function for low-speed signals, such as helicopter rotor speed and turboprop engine propeller speed. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide a magnetoresistive open-circuit detection method for speed signals to solve the technical problem in the prior art that requires a high frequency of speed signal and cannot achieve open-circuit detection function under low speed signal conditions. The method includes:

[0005] The speed signal acquisition and conditioning circuit amplifies the AC speed signal;

[0006] The DC level boosting circuit ensures that the amplitude and frequency of the speed signal are not affected when the sensor is not open-circuited, and that a DC level is superimposed on the speed signal acquisition and conditioning circuit when the sensor is open-circuited.

[0007] The integrating circuit amplifies the ultra-low frequency signal and filters and attenuates both the low-frequency and high-frequency signals.

[0008] A negative feedback saturation prevention circuit ensures that the integrating circuit amplifies the DC signal.

[0009] The open-circuit detection circuit compares the integrated output signal with the reference voltage to ensure that when the speed signal is open-circuited, the integrated output voltage can be effectively identified as an open-circuit voltage, and when the speed signal is not open-circuited, the integrated output voltage can be effectively identified as an open-circuit voltage.

[0010] Furthermore, the speed signal acquisition and conditioning circuit includes a differential amplifier circuit.

[0011] Furthermore, the DC level boosting circuit includes a DC voltage source and a boosting resistor.

[0012] Furthermore, the integrating circuit amplifies the DC input signal by a factor greater than or equal to 50.

[0013] Furthermore, the operation of each circuit includes:

[0014] Calculate the amplification factor of the differential amplifier circuit based on the output voltage range of the rotation speed signal;

[0015] Based on the sensor's internal resistance, the pull-up resistor of the DC level boosting circuit is determined; based on the amplification factor and the sensor's low-frequency output voltage value, the boosting voltage value is determined.

[0016] Based on the sensor output frequency and the voltage value, determine the integrator resistance and capacitance values ​​according to a preset standard;

[0017] Based on the amplification factor, a preset resistance value is determined to form the negative feedback saturation prevention circuit;

[0018] The preset reference voltage is determined based on the different output results of the comparator when the speed signal is open and when the speed signal is not open.

[0019] Furthermore, this invention also provides a magnetoresistive speed signal open-circuit detection system to solve the technical problem in the prior art that requires a high speed signal frequency and cannot achieve open-circuit detection function under low speed signals. The system includes:

[0020] The speed signal acquisition and conditioning circuit module is used to amplify the AC speed signal;

[0021] The DC level boosting circuit module is used to ensure that the amplitude and frequency of the speed signal are not affected when the sensor is not open-circuited, and that a DC level is superimposed on the speed signal acquisition and conditioning circuit when the sensor is open-circuited.

[0022] The integrator circuit module is used to amplify ultra-low frequency signals and filter and attenuate both low-frequency and high-frequency signals.

[0023] A negative feedback saturation prevention circuit module is used to ensure that the integrating circuit amplifies the DC signal;

[0024] The open-circuit detection circuit module is used to compare the integrated output signal with the reference voltage to ensure that when the speed signal is open-circuited, the integrated output voltage can be effectively identified as an open-circuit voltage, and when the speed signal is not open-circuited, the integrated output voltage can be effectively identified as an open-circuit voltage.

[0025] Compared with the prior art, the beneficial effects achieved by at least one of the above-mentioned technical solutions adopted in the embodiments of this specification include at least the following: This invention provides a magnetoresistive speed signal open-circuit detection method, comprising: a speed signal acquisition and conditioning circuit, a DC level boosting circuit, an integrator circuit, a negative feedback saturation prevention circuit, and an open-circuit detection circuit. It employs a hardware integrator, amplifying only ultra-low frequency signals (including DC signals) while filtering and attenuating low-frequency and high-frequency signals. This method can satisfy both sensor open-circuit fault detection and low-frequency and high-frequency signal frequency detection, while ensuring that the sensor output frequency and amplitude do not trigger an open-circuit fault during normal operation. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a hardware schematic diagram of a high-frequency magnetoresistive speed signal open-circuit detection method provided in an embodiment of the present invention;

[0028] Figure 2 This is a hardware schematic diagram of a magnetoresistive speed signal open-circuit detection method provided in an embodiment of the present invention;

[0029] Figure 3 This is an amplitude-frequency curve of a hardware integrator provided in an embodiment of the present invention;

[0030] Figure 4 This is an amplitude-frequency curve of an RC low-pass filter provided in an embodiment of the present invention;

[0031] Figure 5 This is a structural diagram of a magnetoresistive speed signal open-circuit detection system provided in an embodiment of the present invention.

[0032] The attached diagram is labeled as follows: 500, System; 501, Speed ​​signal acquisition and conditioning circuit module; 502, DC level boosting circuit module; 503, Integrating circuit module; 504, Negative feedback saturation prevention circuit module; 505, Open circuit detection circuit module. Detailed Implementation

[0033] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0034] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0035] This invention provides a magnetoresistive speed signal open-circuit detection method, comprising: a speed signal acquisition and conditioning circuit for amplifying the AC speed signal; a DC level boosting circuit to ensure that the speed signal amplitude and frequency are not affected when the sensor is not open-circuited, and that a DC level is superimposed on the speed signal acquisition and conditioning circuit when the sensor is open-circuited; an integrating circuit for amplifying the ultra-low frequency signal and filtering and attenuating both the low-frequency and high-frequency signals; a negative feedback saturation prevention circuit to ensure that the integrating circuit amplifies the DC signal; and an open-circuit detection circuit for comparing the integrated output signal with a reference voltage to ensure that the integrated output voltage can be effectively identified as an open-circuit voltage when the speed signal is open-circuited, and can be effectively identified as an open-circuit voltage when the speed signal is not open-circuited.

[0036] Furthermore, the speed signal acquisition and conditioning circuit includes a differential amplifier circuit.

[0037] Specifically, the speed signal acquisition and conditioning circuit consists of a differential amplifier circuit, which differentially amplifies the output signal of the speed sensor. The amplification factor of the differential amplifier circuit is determined by the maximum value of the sensor output voltage. That is, the amplifier circuit cannot cause the differential amplifier circuit to exceed its limit after the sensor output voltage is amplified.

[0038] Furthermore, the DC level boosting circuit includes a DC voltage source and a boosting resistor.

[0039] Preferably, the DC level rise circuit consists of a DC voltage source and rise resistors, wherein there are two rise power sources and two rise resistors, and the two rise resistors have equal resistance values. The resistance value of the rise resistors is required to be 50 times greater than the internal resistance of the sensor. The two voltages in the rise voltage source are not equal, with the voltage of one rise voltage source being greater than the voltage of the other rise power source. The DC level rise circuit does not affect the normal output voltage of the sensor, and the DC level rise circuit does not cause the differential amplifier circuit to exceed the limits.

[0040] Furthermore, the integrating circuit amplifies the DC input signal by a factor greater than or equal to 50.

[0041] Specifically, the integrating circuit amplifies the DC input signal by no less than 100 times and ensures that the normal output voltage signal of the sensor is effectively attenuated (within the output frequency range of the speed sensor, the amplification factor corresponding to the amplitude-frequency curve of the integrator is less than 1.0).

[0042] Furthermore, the negative feedback saturation prevention circuit is connected to the resistor corresponding to the smaller voltage source of the differential amplifier circuit and the voltage boost circuit through a resistor, forming a negative feedback saturation prevention circuit for the differential amplifier circuit and the integrator circuit. The negative feedback saturation prevention circuit reduces the amplification factor of the integrator for DC signals, thereby preventing the integrator from saturating.

[0043] Furthermore, the operation of each circuit includes:

[0044] Calculate the amplification factor of the differential amplifier circuit based on the output voltage range of the rotation speed signal;

[0045] Based on the sensor's internal resistance, the pull-up resistor of the DC level boosting circuit is determined; based on the amplification factor and the sensor's low-frequency output voltage value, the boosting voltage value is determined.

[0046] Based on the sensor output frequency and the voltage value, determine the integrator resistance and capacitance values ​​according to a preset standard;

[0047] Based on the amplification factor, a preset resistance value is determined to form the negative feedback saturation prevention circuit;

[0048] The preset reference voltage is determined based on the different output results of the comparator when the speed signal is open and when the speed signal is not open.

[0049] Example 1

[0050] Please also refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 ,in, Figure 1 This is a hardware schematic diagram of a high-frequency magnetoresistive open-circuit detection method for rotational speed signals. Figure 2 This is a hardware schematic diagram of a magnetoresistive speed signal open-circuit detection method. Figure 3 It is the amplitude-frequency curve of the hardware integrator. Figure 4 This is the amplitude-frequency curve of an RC low-pass filter.

[0051] Combination Figure 1 , Figure 2 , Figure 3 and Figure 4 ,in Figure 1Based on the circuit described in the patent "An Engine Speed ​​Measurement Circuit and Method" and combined with the method described in "A Magnetoresistive Speed ​​Signal Acquisition Method and System with Open Circuit Detection," this is a modified speed measurement circuit and open circuit detection circuit. The main principle is to identify the open circuit state by utilizing the different voltage boosting effects of the voltage boosting circuit on the subsequent circuit when it is in an open circuit and not in an open circuit state. Its key parameters are those described in this patent. Figure 1 In the non-open-circuit state, R4 and C3 require that the amplitude of the sinusoidal voltage signal after being filtered by the low-pass filter of R4 and C3 be less than the comparison voltage of the comparator. Therefore, the speed signal frequency needs to be relatively high (e.g., Figure 4 It cannot achieve open circuit detection function under low speed signal.

[0052] in Figure 2 This is a hardware schematic diagram of a magnetoresistive open-circuit speed signal detection method. Its specific working principle is as follows: the sensor output signal frequency range is (1~200)Hz, voltage range is (1~5)V, and internal resistance is less than 1.0Kohm (the parameters of each component in the circuit are set according to the sensor parameters); the speed signal acquisition and conditioning circuit consists of R1_1=50Kohm, R1_2=50Kohm, R3=100Kohm, C1=100pF, and operational amplifier 1, which amplifies the AC signal output by the speed sensor by 2 times; the DC level is raised... The boost circuit consists of R0_1 = 220Kohm, R0_2 = 220Kohm, power supply Vcc = 5V, and AGND. When the sensor is not open-circuited, it does not affect the amplitude and frequency of the speed signal. When the sensor is open-circuited, a DC level is superimposed on the speed signal acquisition and conditioning circuit. The integrator circuit consists of R2_1 = 1000Kohm, R2_2 = 1000Kohm, C3 = 220nF, and operational amplifier 2. It amplifies the DC signal infinitely (theoretically) and filters and attenuates both low-frequency and high-frequency signals (e.g., ...). Figure 3 The negative feedback saturation prevention circuit, composed of R6 = 100 Kohm, ensures that the amplification of the DC signal by the integrator circuit does not lead to saturation. The open-circuit detection circuit, composed of R4 = 10 Kohm, R5 = 10 Kohm, a reference voltage Vcc / 2 = 2.5V, and a comparator, compares the integrated output signal with the reference voltage to ensure that when the speed signal is open-circuited, the integrated output voltage can be effectively identified as an open-circuit voltage, and when the speed signal is not open-circuited, the integrated output voltage can be effectively identified as an open-circuit voltage. The circuit working principle is described in detail below:

[0053] When the sensor is not open-circuited, the speed sensor outputs an AC voltage signal. Since the pull-up resistors for the DC boost voltage Vcc and AGND are much larger than the sensor's internal resistance, they do not affect the operational amplifier's amplification factor. Therefore, the sensor's output AC voltage signal is amplified by operational amplifier 1 and then passes through a frequency detection device to measure the frequency of the speed sensor's output AC signal. Simultaneously, the AC voltage signal output by operational amplifier 1 is filtered and attenuated by an integrator (e.g., ...). Figure 3 Since the integrated voltage signals are all less than 2.5V, the comparator output level is Vcc (high level).

[0054] When the sensor is open-circuited, the speed sensor output is also open-circuited. The DC boost voltage Vcc and AGND are amplified by operational amplifier 1, and the op-amp output voltage is a (-Vcc / 2.7)V DC signal. After passing through the frequency detection device, the signal frequency when the speed sensor output is open-circuited is measured to be "0" Hz. At the same time, the (-Vcc / 2.7)V DC signal output by operational amplifier 1 is further filtered and amplified by an integrator (see...). Figure 3 The integrated voltage signal is (Vcc*3.7 / 2.7)V, which is greater than the comparator reference voltage of 0.5V. Therefore, the comparator output level is 0V (low level).

[0055] Based on the same inventive concept, this invention also provides a magnetoresistive speed signal open-circuit detection system, as described in the following embodiments. Since the principle of solving the problem in a magnetoresistive speed signal open-circuit detection system is similar to that of a magnetoresistive speed signal open-circuit detection method, the implementation of a magnetoresistive speed signal open-circuit detection system can refer to the implementation of a magnetoresistive speed signal open-circuit detection method, and repeated details will not be elaborated further. As used below, the terms "unit" or "module" can refer to a combination of software and / or hardware that performs a predetermined function. Although the system described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0056] like Figure 5 The diagram shown is a schematic of a magnetoresistive speed signal open-circuit detection system 500 according to an embodiment of the present invention, comprising:

[0057] The speed signal acquisition and conditioning circuit module 501 is used to amplify the speed AC signal;

[0058] The DC level boosting circuit module 502 is used to ensure that the amplitude and frequency of the speed signal are not affected when the sensor is not open-circuited, and that a DC level is superimposed on the speed signal acquisition and conditioning circuit when the sensor is open-circuited.

[0059] The integrator module 503 is used to amplify ultra-low frequency signals and filter and attenuate both low-frequency and high-frequency signals.

[0060] The negative feedback saturation prevention circuit module 504 is used to ensure that the integrating circuit amplifies the DC signal;

[0061] The open-circuit detection circuit module 505 is used to compare the integrated output signal with the reference voltage to ensure that when the speed signal is open-circuited, the integrated output voltage can be effectively identified as an open-circuit voltage, and when the speed signal is not open-circuited, the integrated output voltage can be effectively identified as an open-circuit voltage.

[0062] The embodiments of the present invention achieve the following technical effects:

[0063] This invention provides a magnetoresistive speed signal open-circuit detection method and system, employing a hardware integrator that amplifies only ultra-low frequency signals (including DC signals) while filtering and attenuating low-frequency and high-frequency signals. It satisfies both sensor open-circuit fault detection and low-frequency and high-frequency signal detection, while ensuring that the sensor output frequency and amplitude do not trigger an open-circuit fault during normal operation. This invention is simple in design, easy to implement, and has strong anti-interference capabilities. It can effectively detect open-circuit faults in speed signals without affecting the speed frequency range or the signal frequency acquisition accuracy.

[0064] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, various modifications and variations can be made to the embodiments of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for detecting open-circuit speed signals using a reluctance type, characterized in that, include: The speed signal acquisition and conditioning circuit amplifies the AC speed signal; The DC level boosting circuit ensures that the amplitude and frequency of the speed signal are not affected when the sensor is not open-circuited, and that a DC level is superimposed on the speed signal acquisition and conditioning circuit when the sensor is open-circuited. The integrating circuit amplifies the ultra-low frequency signal and filters and attenuates both the low-frequency and high-frequency signals. A negative feedback saturation prevention circuit ensures that the integrating circuit amplifies the DC signal. The open-circuit detection circuit compares the integrated output signal with the reference voltage to ensure that when the speed signal is open-circuited, the integrated output voltage can be effectively identified as the open-circuit voltage, and when the speed signal is not open-circuited, the integrated output voltage can be effectively identified as the non-open-circuit voltage. The speed signal acquisition and conditioning circuit includes a differential amplifier circuit; The integrating circuit amplifies the DC input signal by a factor greater than or equal to 50. The working process of each circuit includes: Calculate the amplification factor of the differential amplifier circuit based on the output voltage range of the rotation speed signal; Based on the sensor's internal resistance, the pull-up resistor of the DC level boosting circuit is determined; based on the amplification factor and the sensor's low-frequency output voltage value, the boosting voltage value is determined. Based on the sensor output frequency and the voltage value, determine the integrator resistance and capacitance values ​​according to a preset standard; Based on the amplification factor, a preset resistance value is determined to form the negative feedback saturation prevention circuit; The preset reference voltage is determined based on the different output results of the comparator when the speed signal is open and when the speed signal is not open.

2. The method for open-circuit detection of reluctance-type speed signal according to claim 1, characterized in that, The DC level boosting circuit includes a DC voltage source and a boosting resistor.

3. A magnetoresistive speed signal open-circuit detection system, characterized in that, The system is used to perform the method of claim 1 or 2, and the system comprises: The speed signal acquisition and conditioning circuit module is used to amplify the AC speed signal; The DC level boosting circuit module is used to ensure that the amplitude and frequency of the speed signal are not affected when the sensor is not open-circuited, and that a DC level is superimposed on the speed signal acquisition and conditioning circuit when the sensor is open-circuited. The integrator circuit module is used to amplify ultra-low frequency signals and filter and attenuate both low-frequency and high-frequency signals. A negative feedback saturation prevention circuit module is used to ensure that the integrating circuit amplifies the DC signal; The open-circuit detection circuit module is used to compare the integrated output signal with the reference voltage to ensure that when the speed signal is open-circuited, the integrated output voltage can be effectively identified as an open-circuit voltage, and when the speed signal is not open-circuited, the integrated output voltage can be effectively identified as an open-circuit voltage.

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