Wind speed sensor measurement circuit and method

Abstract

The present invention provides a wind speed sensor measurement circuit and method, wherein a logic control circuit is used to switch the positions of two temperature measuring resistors in a resistance division circuit, and the resistance division circuit is used to perform a division operation on the two temperature measuring resistors of the wind speed sensor to be measured. A main control circuit generates a wind speed signal based on the output signal of the resistance division current to complete the wind speed measurement. Compared with the bridge circuit in the prior art, this circuit structure has an essentially different measurement principle. From the perspective of the circuit principle, it can significantly improve the response characteristics of the wind speed sensor at high wind speeds and increase the resolution of the wind speed sensor at high wind speeds.

Description

Technical Field

[0001] The present invention relates to the field of meteorological observation, and in particular to a wind speed sensor measurement circuit and method. Background Art

[0002] In the field of meteorological observation, wind speed is one of the most fundamental meteorological factors, affecting production and living standards, as well as the safety of life and property. Currently, a variety of wind speed measurement methods exist, each with its own advantages and suitability for different scenarios. Hot-film wind speed sensors, based on MEMS (Micro-Electro-Mechanical System) technology, have become an emerging and rapidly developing wind speed sensor due to their small size, ease of integration, high accuracy, and low power consumption. However, these sensors have a narrow wind speed measurement range, which severely limits their application. Therefore, targeted research on this issue is necessary.

[0003] Wind speed sensors are the core of wind speed measurement. To improve sensor performance, research on wind speed sensors has primarily focused on the sensor's substrate and structure, attempting to improve the sensor's high wind speed response sensitivity by reducing the sensor's heat loss rate, thereby expanding the wind speed measurement range. In terms of wind speed measurement circuit design, innovative research is limited. Common circuit measurement schemes use a constant temperature difference circuit to achieve resistor heating and a bridge circuit to read the wind speed of a temperature measuring resistor. At low wind speeds, the bridge circuit can achieve a high resolution, but as the wind speed increases, the resolution gradually decreases until it reaches zero. This characteristic is one of the key drawbacks of MEMS wind speed sensors and severely limits their use cases. Summary of the Invention

[0004] In response to the above problems, the present invention provides a wind speed sensor measurement circuit and method, which improves the response characteristics of the wind speed sensor at high wind speeds and enhances the resolution of the wind speed sensor at high wind speeds from the perspective of circuit principles.

[0005] In a first aspect, an embodiment of the present invention provides a measurement circuit of a wind speed sensor, wherein the wind speed sensor includes a first temperature measuring resistor and a second temperature measuring resistor, and the measurement circuit includes:

[0006] a resistance division circuit connected to the wind speed sensor to be measured, and configured to perform a division operation on the first temperature measuring resistor and the second temperature measuring resistor of the wind speed sensor to be measured to obtain an output signal;

[0007] A logic control circuit is connected to the output terminal and the input terminal of the resistance division circuit, and is used to control the position switching of the first temperature measuring resistor and the second temperature measuring resistor of the wind speed sensor to be measured;

[0008] A main control circuit is connected to the resistance division circuit and the logic control circuit, and is used to generate a wind speed signal according to the output signal.

[0009] In some embodiments, the resistance division circuit includes:

[0010] an analog switch, wherein a first end and a second end of the analog switch are connected to a reference signal, a third end of the analog switch is connected to one end of the second temperature measuring resistor, the other end of the second temperature measuring resistor is connected to one end of the first temperature measuring resistor, and the other end of the first temperature measuring resistor is connected to a fourth end of the analog switch, and the analog switch is used to switch the positions of the first temperature measuring resistor and the second temperature measuring resistor;

[0011] A resistance divider, wherein the inverting input terminal is connected to the other end of the second temperature measuring resistor, the non-inverting input terminal is connected to one end of the compensation resistor, the other end of the compensation resistor is grounded, the output terminal of the resistance divider is connected to the fifth and sixth terminals of the analog switch, and the resistance divider is used to perform a division operation on the first temperature measuring resistor and the second temperature measuring resistor.

[0012] In some embodiments, the logic control circuit includes:

[0013] an analog comparator, wherein a reference signal is input to a non-inverting input terminal and a flip signal of the output signal of the resistance divider is input to an inverting input terminal, and the analog comparator compares the reference signal and the flip signal, and an output terminal of the analog comparator is connected to a voltage divider circuit;

[0014] A JK trigger, wherein the J terminal, the K terminal, and the clock signal pin are connected to the main control circuit, the clock signal pin is also connected to the voltage divider circuit, the output terminal of the JK trigger is connected to the input terminal of the analog switch, and the states of the J terminal and the K terminal are set by the main control circuit according to the output signal of the resistance divider to control the position switching of the first temperature measuring resistor and the second temperature measuring resistor.

[0015] In some embodiments, the voltage divider circuit includes:

[0016] a third resistor, one end of which is connected to the output end of the analog comparator;

[0017] a fourth resistor, one end of which is connected to the other end of the third resistor, and the other end of which is grounded;

[0018] The clock signal pin is connected to the connection line of the third resistor and the fourth resistor.

[0019] In some embodiments, the logic control circuit further includes:

[0020] The first low-pass filter circuit is connected to the output end of the JK trigger and is used to filter out high-frequency noise at the output end of the JK trigger.

[0021] In some embodiments, the measurement circuit of the wind speed sensor further includes:

[0022] a signal conditioning circuit, one end of which is connected to the output end of the resistance divider, and is used to remove high-frequency interference signals from the output signal of the resistance divider;

[0023] The analog-to-digital conversion circuit has an input end connected to the output end of the signal conditioning circuit, and an output end of the analog-to-digital conversion circuit is connected to the main control circuit, and is used to perform analog-to-digital conversion on the output signal after removing the high-frequency interference signal and then send it to the main control circuit.

[0024] In some embodiments, the signal conditioning circuit includes:

[0025] a voltage inversion circuit, the input end of which is connected to the output end of the resistance divider, for inverting the output signal of the resistance divider to obtain an inversion signal; the output end of the voltage inversion circuit is connected to the input end of the logic control circuit to connect the inversion signal to the logic control circuit;

[0026] The second low-pass filter circuit has an input end connected to the output end of the voltage inversion circuit, and an output end of the second low-pass filter circuit is connected to the input end of the analog-to-digital conversion circuit.

[0027] In some embodiments, the resistance divider includes an operational amplifier, and the operational amplifier satisfies at least the following conditions:

[0028] The sum of the bias current and the input offset current of the operational amplifier is less than a preset threshold.

[0029] In a second aspect, an embodiment of the present invention provides a method for measuring a wind speed sensor, which is implemented based on the measurement circuit described in the first aspect. The method includes:

[0030] The resistance division circuit performs a division operation on the first temperature measuring resistor and the second temperature measuring resistor of the wind speed sensor to obtain an output signal;

[0031] The logic control circuit controls the position switching of the first temperature measuring resistor and the second temperature measuring resistor of the wind speed sensor to be measured so that the amplitude of the output signal is greater than the input reference signal;

[0032] The main control circuit generates a wind speed signal according to the output signal.

[0033] In some embodiments, when the logic control circuit outputs a high-level signal, the output signal is the product of the ratio of the first temperature measuring resistor to the second temperature measuring resistor and the reference signal; when the logic control circuit outputs a low-level signal, the output signal is the product of the ratio of the second temperature measuring resistor to the first temperature measuring resistor and the reference signal.

[0034] Compared with the prior art, one or more embodiments of the present invention can bring at least the following beneficial effects:

[0035] The present invention uses a logic control circuit to complete the position switching of the two temperature measuring resistors in the resistance division circuit, completes the division operation of the two temperature measuring resistors of the wind speed sensor to be measured through the resistance division circuit, and generates a wind speed signal according to the output signal of the resistance division current by the main control circuit to complete the wind speed measurement. Compared with the bridge circuit in the prior art, this circuit structure has an essentially different measurement principle, can significantly improve the response characteristics of the wind speed sensor at high wind speeds, and improve the resolution of the wind speed sensor at high wind speeds. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope.

[0037] Figure 1 This is the internal schematic diagram of the MEMS wind speed sensor;

[0038] Figure 2 This is a schematic diagram using a traditional bridge circuit as the measurement circuit;

[0039] Figure 3 This is a measurement circuit connection block diagram of a wind speed sensor provided by an embodiment of the present invention;

[0040] Figure 4 1 is a schematic diagram of a resistance division circuit provided by an embodiment of the present invention;

[0041] Figure 5 yes Figure 4 The error analysis schematic diagram of the resistance division circuit shown;

[0042] Figure 6 is a schematic diagram of a logic control circuit provided by an embodiment of the present invention;

[0043] Figure 7 1 is a schematic diagram of a signal conditioning circuit provided by an embodiment of the present invention;

[0044] Figure 8 This is a flow chart of a measurement method for a wind speed sensor provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0046] Example 1

[0047] In practical applications, there are many heating schemes for MEMS hot film wind speed sensors, including constant temperature difference, constant power, constant pressure, etc. In this embodiment, the design is based on the constant temperature difference heating circuit and related theoretical analysis is carried out. In this embodiment, the design of the constant temperature difference heating circuit is not elaborated in detail. In order to make it easier to understand the circuit principle and advantages of this embodiment, Figure 1 A diagram of the internal circuit of a MEMS hot-film wind speed sensor is provided. The sensor's main electrical features include a heating platinum resistor R5 and two symmetrically designed temperature-measuring platinum resistors R1 and R2 (also called the first temperature-measuring resistor R1 and the second temperature-measuring resistor R2). During wind speed measurement, the change directions of R1 and R2 are always opposite. Figure 1 The R3, R4, and R6 shown in the figure have different meanings from the resistors with the same name in other figures.

[0048] The measurement circuit of the wind speed sensor provided in this embodiment can be applied to Figure 1 The wind speed sensor shown in FIG. 1 includes a first temperature measuring resistor R1 and a second temperature measuring resistor R2. Figure 3 As shown, the measurement circuit includes:

[0049] The resistance division circuit 200 is connected to the wind speed sensor 100 to perform a division operation on the first temperature measuring resistor R1 and the second temperature measuring resistor R2 of the wind speed sensor 100 to obtain an output signal;

[0050] The logic control circuit 300 is connected to the output terminal and the input terminal of the resistance division circuit 200 and is used to control the position switching of the first temperature measuring resistor R1 and the second temperature measuring resistor R2 of the wind speed sensor 100 to be measured;

[0051] The main control circuit 600 is connected to the resistance division circuit 200 and the logic control circuit 300 and is used to generate a wind speed signal according to the output signal.

[0052] The measurement circuit of this embodiment uses a logic control circuit to complete the position switching of the two temperature measuring resistors in the resistance division circuit, and uses the resistance division circuit to complete the division operation of the two temperature measuring resistors of the wind speed sensor to be measured. The main control circuit generates a wind speed signal based on the output signal of the resistance division current to complete the wind speed measurement. Compared with the bridge circuit in the prior art, this circuit structure has an essentially different measurement principle and can significantly improve the response characteristics of the wind speed sensor at high wind speeds and increase the resolution of the wind speed sensor at high wind speeds.

[0053] In some implementations, such as Figure 4 As shown, the resistance division circuit 200 includes: an analog switch 201 ( Figure 4 U1 in ) and resistor divider 202.

[0054] The first end S1A and the second end S2B of the analog switch U1 are connected to the reference signal Vref, the third end D1 of the analog switch U1 is connected to one end of the second temperature measuring resistor R2, the other end of the second temperature measuring resistor R2 is connected to one end of the first temperature measuring resistor R1, and the other end of the first temperature measuring resistor R1 is connected to the fourth end D2 of the analog switch U1. The analog switch U1 is used to switch the positions of the first temperature measuring resistor R1 and the second temperature measuring resistor R2.

[0055] The resistance divider 202 is a basic out-of-phase amplifier circuit, including an operational amplifier U2A, whose inverting input terminal is connected to the other end of the second temperature measuring resistor R2, and whose non-inverting input terminal is connected to one end of the compensation resistor R17, and the other end of the compensation resistor R17 is grounded. The output end of the resistance divider 202 (the output end of the operational amplifier U2A) is connected to the fifth end S1B and the sixth end S2A of the analog switch U1. The resistance divider 202 is used to perform a division operation on the first temperature measuring resistor R1 and the second temperature measuring resistor R2.

[0056] exist Figure 4 In the resistance division circuit 200 shown, S1A and S2B on one side of the analog switch U1 are connected to the reference voltage Vref, S1B and S2A are connected to the output Out- of the operational amplifier U2A, and IN1 is connected to IN2, which is connected to the output IN of the logic control circuit. Figure 5 As shown, the resistance division circuit contains two equivalent resistors, R15 and R16. Selecting a precision analog switch with an on-resistance less than 3Ω can negligibly affect the circuit's measurement errors. Analog switch U1 is preferably a dual-channel single-pole double-throw analog switch.

[0057] In some implementations, the sum of the bias current and input offset current of the operational amplifier U2A needs to be less than a certain threshold to ensure the accuracy of the measurement circuit. Therefore, the operational amplifier U2A should at least meet the following conditions: the bias current and input offset current of the operational amplifier U2A are both less than a preset threshold.

[0058] In some implementations, such as Figure 6 As shown, the logic control circuit 300 includes: an analog comparator 301 ( Figure 6 U2B in) and JK flip-flop 302 ( Figure 6 Optionally, the JK trigger is a rising edge trigger. The logic control circuit 300 is used to complete the position switching of the two temperature measuring resistors in the resistance division circuit.

[0059] The analog comparator 301 has its non-inverting input connected to the reference signal Vref and its inverting input connected to the inverted signal Out+ of the output signal Out- of the resistance divider. The analog comparator 301 compares the reference signal Vref with the inverted signal Out+. The output of the analog comparator 301 is connected to the voltage divider circuit 303. The comparison result of the analog comparator 301 is used to control the state of the analog switch 201.

[0060] The J terminal, K terminal, and clock signal pin CLK of the JK trigger 302 are connected to GPIO1, GPIO2, and GPIO3 of the main control circuit 600. The clock signal pin CLK is also connected to the voltage divider circuit 303. The output terminal Q of the JK trigger 302 is connected to the input terminal IN of the analog switch 201. The status of the J terminal and the K terminal is set by the main control circuit 600 according to the output signal of the resistance divider 202 to control the position switching of the first temperature measuring resistor R1 and the second temperature measuring resistor R2. The PRE terminal and the CLR terminal of the JK trigger 302 are connected to the high level VCC.

[0061] In some implementations, the voltage divider circuit 303 includes:

[0062] A third resistor R3, one end of which is connected to the output end of the analog comparator 301;

[0063] A fourth resistor R4, one end of which is connected to the other end of the third resistor R3, and the other end of the fourth resistor R4 is grounded;

[0064] The clock signal pin CLK is connected to a connection line between the third resistor R3 and the fourth resistor R4.

[0065] The high level output by the analog comparator 301 can be reduced by the voltage divider circuit 303 so that its output voltage can trigger the JK flip-flop.

[0066] In some implementations, the logic control circuit 300 further includes:

[0067] The first low-pass filter circuit 304 is connected to the output terminal Q of the JK flip-flop 302 and is used to filter out high-frequency noise at the output terminal of the JK flip-flop 302 .

[0068] In some implementations, the first low-pass filter circuit 304 includes:

[0069] A resistor R18, one end of which is connected to the output terminal Q of the JK flip-flop 302;

[0070] One end of the capacitor C1 is connected to the other end of the resistor R18 , and the other end of the capacitor C1 is grounded.

[0071] The reference signal Vref in the resistance division circuit and the logic control circuit is the same reference voltage.

[0072] In some implementations, the measurement circuit of the wind speed sensor further includes: a signal conditioning circuit 400 and an analog-to-digital conversion circuit 500;

[0073] One end of the signal conditioning circuit 400 is connected to the output end Out- of the resistance divider 202, and is used to remove the high-frequency interference signal caused by the analog switch in the output signal of the resistance divider 202; the input end of the analog-to-digital conversion circuit 500 is connected to the output end of the signal conditioning circuit 400, and the output end of the analog-to-digital conversion circuit 500 is connected to the main control circuit 600, and is used to perform analog-to-digital conversion on the output signal after removing the high-frequency interference signal and send it to the main control circuit 600.

[0074] In some implementations, such as Figure 7 As shown, the signal conditioning circuit 400 includes: a voltage flip circuit 401 and a second low-pass filter circuit 402;

[0075] The input of the voltage inversion circuit 401 is connected to the output of the resistance divider 202 and is used to invert the output signal Out- of the resistance divider 202 to generate an inverted signal Out+, that is, to convert the negative voltage output by the resistance divider into a positive voltage. The output of the voltage inversion circuit 401 is connected to the input of the logic control circuit 300 (the input of the analog comparator 301) to connect the inverted signal Out+ to the logic control circuit 300 (the input of the analog comparator 301).

[0076] An input end of the second low-pass filter circuit 402 is connected to an output end of the voltage inversion circuit 401 , and an output end of the second low-pass filter circuit 402 is connected to an input end of the analog-to-digital conversion circuit 500 .

[0077] In some implementations, the voltage flipping circuit 401 includes: an out-of-phase amplifier circuit based on the operational amplifier U3B. Further, the voltage flipping circuit 401 also includes:

[0078] a resistor R8 having one end connected to the output of the resistance divider 202 and the other end connected to the inverting input of the operational amplifier U3B;

[0079] Resistor R12, one end of which is connected to the non-inverting input of operational amplifier U3B and the other end is grounded;

[0080] The resistor R5 is connected between the inverting input terminal and the output terminal of the operational amplifier U3B.

[0081] Among them, R5=R8, R12=R5||R8 are compensation resistors, and the gain is -1.

[0082] In some implementations, the second low-pass filter circuit 402 includes: a second-order Butterworth filter circuit based on an operational amplifier U3A. In some implementations, the second low-pass filter circuit 402 also includes:

[0083] Resistor R9, one end of which is connected to the output of operational amplifier U3B;

[0084] Resistor R10, one end and the other end of resistor R9, the other end of which are connected to the non-inverting input terminal of operational amplifier U3A;

[0085] Resistor R6, one end of which is connected to the output of operational amplifier U3A;

[0086] Resistor R7, one end of which is connected to the other end of resistor R6, and the other end of which is grounded. The inverting input end of operational amplifier U3A is also connected to the connection line between resistor R6 and resistor R7;

[0087] Capacitor C3, one end of which is connected to the connection line between resistors R9 and R10, and the other end of which is connected to the output terminal of operational amplifier U3A;

[0088] One end of capacitor C4 is connected to the connection line between resistor R10 and the same-direction input terminal of operational amplifier U3A, and the other end is grounded;

[0089] The capacitors C3 and C4 are used to filter out high-frequency noise in the circuit, and the output end of the operational amplifier U3A is connected to the analog-to-digital conversion circuit 500 .

[0090] After power-up, the main control circuit 600 sets the states of the J and K terminals of the JK flip-flop 302 based on the reading from the analog-to-digital conversion circuit 500 (i.e., the output of the signal conditioning circuit U3A converted into a digital signal). If the GPIO3 signal received by the main control circuit 600 is high, the J and K states are switched, causing the output Q to be set to 0 or 1, thereby changing the output state of the JK flip-flop. This change in logic value between 0 and 1 switches the state of the analog switch U1. If the GPIO3 signal received by the main control circuit 600 is low, J=1 and K=1 are set, and the JK flip-flop 302 enters its normal rising-edge triggered operating state. The first low-pass filter circuit 304, consisting of resistor R18 and capacitor C1 connected to the JK flip-flop 302, filters out high-frequency noise at the output Q of the JK flip-flop 302. The main control circuit 600 calculates the wind speed from the digital signal output by the analog-to-digital conversion circuit and presets the J and K levels of the JK flip-flop of the logic control circuit based on the reading from the analog-to-digital conversion circuit 500 after power-up.

[0091] The state of analog switch U1 is determined by the output state of JK flip-flop 302. When the output terminal Q of JK flip-flop 302 outputs a high level, analog switches S1A and S2A of U1 are turned on, while analog switches S1B and S2A of U1 are turned off. The output signal satisfies Out-=-Vref*R1 / R2. When the output terminal Q of JK flip-flop 302 outputs a low level, analog switches S1B and S2B of U1 are turned off, while S1B and S2A of U1 are turned on. The output signal satisfies Out-=-Vref*R2 / R1. In other words, the amplitude of the output signal Out- is always greater than the reference signal Vref according to the different states of analog switch U1.

[0092] In order to better understand the circuit principle and advantages of this embodiment, Figure 2 A schematic diagram of a conventional bridge circuit is provided as the measurement circuit. R13 and R14 have equal resistance values, representing the static resistance of R1 and R2 in the absence of wind, denoted by R. Because the directions of change for R1 and R2 are always opposite, for ease of derivation, R1 is denoted by R+Δr and R2 by R-Δr, where Δr is the resistance change. If an amplifier circuit (not shown) is connected to the back end and the amplification factor is K1, the output f(Δr) of the bridge circuit is expressed as:

[0093]

[0094] If Δr∈[0, R / 2], then:

[0095]

[0096] In order to calculate the changing trend of the output, calculate the derivative of f(Δr):

[0097]

[0098] Among them, V ref is the reference voltage.

[0099] exist Figure 4 In the resistance division circuit shown, the resistance divider adopts a basic out-of-phase amplifier circuit. The amplification factor of the operational amplifier U2A at the back end is K2, and its output absolute value expression is:

[0100]

[0101] If Δr∈[0, R / 2], then:

[0102]

[0103] If the lengths of h(Δr) and f(Δr) are equal, that is, the output voltage ranges are equal, for the convenience of calculation, let:

[0104] K1=7.5 (6)

[0105] K2=1 (7)

[0106] To calculate the changing trend of the output voltage f(Δr), calculate the derivative:

[0107]

[0108] For intuitive comparison, the output curve change rate at 0 wind speed (Δr = 0) and maximum wind speed (Δr = R / 2) is taken as follows:

[0109]

[0110]

[0111]

[0112]

[0113] Therefore, from equations (9) to (12), we can see that the modified circuit of this embodiment changes the wind speed sensor's wind speed-voltage output relationship. Compared with the traditional bridge circuit, by reducing its low-speed resolution, the sensor's high-speed resolution is improved, thereby improving the high-speed response characteristics of the MEMS wind speed sensor.

[0114] In the resistance division circuit, the compensation resistor R17 is used to reduce the error caused by the input bias current and offset current of the integrated operational amplifier. In order to reduce the impact of this error, the resistance value of the compensation resistor R17 needs to be set. In a conventional circuit, R1 and R2 are fixed values, so that R17 = R1||R2. However, in this embodiment, since R1 and R2 are variable resistors, when R17 is a fixed value resistor, its circuit bias current and offset current will cause the measurement error to change. Assume that the bias current of the non-inverting input terminal of the operational amplifier is The bias current at the out-of-phase input is The input offset current is Ios. Then the output error is V oΔ :

[0115]

[0116] If R 17 =R1||R2, then:

[0117]

[0118] However, since R1 and R2 may change at any time during operation, in order to estimate the impact of the maximum error on the measurement system, combined with the extreme value (maximum voltage) of the wind speed sensor in actual operation, take:

[0119] R 17 =3*R1||R2=3*R||R,

[0120] Then we have:

[0121] In order for the measurement circuit to meet the performance requirements, it is necessary to:

[0122]

[0123] Among them, V scale is the output voltage range of the wind speed sensor, S scale is the measured wind speed range, S res is the wind speed resolution requirement. All are estimated based on extreme values, V scale 1V, S scale is 40m / s, S res is 0.1m / s. In this embodiment, the maximum value of R is 1000Ω. Then:

[0124]

[0125] Currently, selecting a precision op amp with bias current and offset current in the pA level can effectively reduce measurement errors and meet the circuit measurement accuracy requirements. Therefore, it is easy to select an operational amplifier that meets the usage requirements.

[0126] like Figure 5 The figure shows the error analysis principle diagram of the resistance division circuit in this embodiment. Due to the on-resistance of the analog switch, there are two equivalent resistors R15 and R16 in the circuit, both of which are δr. The expected output error equation H(Δr) is:

[0127]

[0128] In the above formula, δr is in Ω and R is in kilo-Ω. Therefore, the measurement error caused by this is less than 1%. If a precision analog switch (with an on-resistance δr in Ω, for example, 1Ω) is selected, this error can be reduced to less than 1‰. Therefore, the influence of the analog switch on the circuit measurement error is negligible.

[0129] It should be noted that the wind speed signal is converted into an analog voltage signal by the circuit, and the voltage signal is converted into a digital signal by the analog-to-digital conversion circuit. The size of the digital signal is positively correlated with the wind speed, but under normal circumstances this relationship is nonlinear. The voltage-wind speed relationship can be obtained through experimental calibration, and the relationship can be written into the controller of the main control circuit in advance by analytical fitting or table interpolation to complete real-time measurement and calculation of wind speed.

[0130] Example 2

[0131] This embodiment provides a method for measuring a wind speed sensor, which is implemented based on the measurement circuit of the embodiment. Figure 8 As shown, the measurement method includes:

[0132] Step S201: A resistance division circuit performs a division operation on a first temperature measuring resistor and a second temperature measuring resistor of a wind speed sensor to obtain an output signal.

[0133] Step S202: The logic control circuit controls the position switching of the first temperature measuring resistor and the second temperature measuring resistor of the wind speed sensor to be measured so that the amplitude of the output signal is greater than the input reference signal;

[0134] Step S203: The main control circuit generates a wind speed signal according to the output signal.

[0135] In some embodiments, when the logic control circuit outputs a high-level signal, the output signal is the product of the ratio of the first temperature measuring resistor to the second temperature measuring resistor and the reference signal: Out-=-Vref*R1 / R2; when the logic control circuit outputs a low-level signal, the output signal is the product of the ratio of the second temperature measuring resistor to the first temperature measuring resistor and the reference signal: Out-=-Vref*R2 / R1.

[0136] In the several embodiments provided in the embodiments of the present invention, it should be understood that the disclosed system and method can also be implemented in other ways. The above-described system and method embodiments are merely illustrative.

[0137] It should be noted that, in this document, the terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. The terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements includes not only those elements, but also includes other elements that are not explicitly listed, or also includes elements that are inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a..." does not exclude the presence of other identical elements in the process, method, article or device that includes the element.

[0138] Although the embodiments disclosed herein are as described above, the contents described herein are merely embodiments for facilitating understanding of the present invention and are not intended to limit the present invention. Any person skilled in the art may make any modifications and variations in the form and details of the embodiments without departing from the spirit and scope of the present invention. However, the scope of patent protection of the present invention shall remain subject to the scope defined by the appended claims.

Claims

1. A measurement circuit for a wind speed sensor, the wind speed sensor comprising a first temperature measuring resistor and a second temperature measuring resistor, characterized in that: The measuring circuit comprises: a resistance division circuit connected to the wind speed sensor to be measured, and configured to perform a division operation on the first temperature measuring resistor and the second temperature measuring resistor of the wind speed sensor to be measured to obtain an output signal; A logic control circuit is connected to the output terminal and the input terminal of the resistance division circuit, and is used to control the position switching of the first temperature measuring resistor and the second temperature measuring resistor of the wind speed sensor to be measured; a main control circuit, connected to the resistance division circuit and the logic control circuit, and configured to generate a wind speed signal according to the output signal; The resistance division circuit includes: an analog switch, wherein a first end and a second end of the analog switch are connected to a reference signal, a third end of the analog switch is connected to one end of the second temperature measuring resistor, the other end of the second temperature measuring resistor is connected to one end of the first temperature measuring resistor, and the other end of the first temperature measuring resistor is connected to a fourth end of the analog switch, and the analog switch is used to switch the positions of the first temperature measuring resistor and the second temperature measuring resistor; a resistance divider, wherein the inverting input terminal is connected to the other end of the second temperature measuring resistor, the non-inverting input terminal is connected to one end of the compensation resistor, the other end of the compensation resistor is grounded, the output terminal of the resistance divider is connected to the fifth terminal and the sixth terminal of the analog switch, and the resistance divider is used to perform a division operation on the first temperature measuring resistor and the second temperature measuring resistor; The logic control circuit includes: an analog comparator, wherein a reference signal is input to a non-inverting input terminal and a flip signal of the output signal of the resistance divider is input to an inverting input terminal, and the analog comparator compares the reference signal and the flip signal, and an output terminal of the analog comparator is connected to a voltage divider circuit; A JK trigger, wherein the J terminal, the K terminal, and the clock signal pin are connected to the main control circuit, the clock signal pin is also connected to the voltage divider circuit, the output terminal of the JK trigger is connected to the input terminal of the analog switch, and the states of the J terminal and the K terminal are set by the main control circuit according to the output signal of the resistance divider to control the position switching of the first temperature measuring resistor and the second temperature measuring resistor; The resistance divider includes an operational amplifier, and the operational amplifier at least meets the following conditions: The sum of the bias current and the input offset current of the operational amplifier is less than a preset threshold.

2. The measurement circuit of the wind speed sensor according to claim 1, characterized in that: The voltage divider circuit comprises: a third resistor, one end of which is connected to the output end of the analog comparator; a fourth resistor, one end of which is connected to the other end of the third resistor, and the other end of which is grounded; The clock signal pin is connected to the connection line of the third resistor and the fourth resistor.

3. The measurement circuit of the wind speed sensor according to claim 1, characterized in that: The logic control circuit further includes: The first low-pass filter circuit is connected to the output end of the JK trigger and is used to filter out high-frequency noise at the output end of the JK trigger.

4. The measurement circuit of the wind speed sensor according to claim 1, characterized in that: Also includes: a signal conditioning circuit, one end of which is connected to the output end of the resistance divider, and is used to remove high-frequency interference signals from the output signal of the resistance divider; The analog-to-digital conversion circuit has an input end connected to the output end of the signal conditioning circuit, and an output end of the analog-to-digital conversion circuit is connected to the main control circuit, and is used to perform analog-to-digital conversion on the output signal after removing the high-frequency interference signal and then send it to the main control circuit.

5. The measurement circuit of the wind speed sensor according to claim 4, characterized in that: The signal conditioning circuit comprises: a voltage inversion circuit, the input end of which is connected to the output end of the resistance divider, for inverting the output signal of the resistance divider to obtain an inversion signal; the output end of the voltage inversion circuit is connected to the input end of the logic control circuit to connect the inversion signal to the logic control circuit; The second low-pass filter circuit has an input end connected to the output end of the voltage inversion circuit, and an output end of the second low-pass filter circuit is connected to the input end of the analog-to-digital conversion circuit.

6. A method for measuring a wind speed sensor, characterized in that: Based on the measurement circuit implementation according to any one of claims 1 to 5, the measurement method includes: The resistance division circuit performs a division operation on the first temperature measuring resistor and the second temperature measuring resistor of the wind speed sensor to obtain an output signal; The logic control circuit controls the position switching of the first temperature measuring resistor and the second temperature measuring resistor of the wind speed sensor to be measured so that the amplitude of the output signal is greater than the input reference signal; The main control circuit generates a wind speed signal according to the output signal.

7. The wind speed sensor measurement method according to claim 6, characterized in that: In the case where the logic control circuit outputs a high level signal, the output signal is the product of the ratio of the first temperature measuring resistor to the second temperature measuring resistor and the reference signal; In the case where the logic control circuit outputs a low-level signal, the output signal is a product of a ratio of the second temperature measuring resistor to the first temperature measuring resistor and the reference signal.

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