A motor speed measuring device

Abstract

The application relates to the technical field of motor rotating speed detection, and discloses a motor rotating speed detection device which comprises a signal generation unit, a signal detection unit and a control unit. Compared with the current technology, the signals collected by different types of sensors can be unstable or inaccurate, the additional signal generation unit is used as a signal sending device, the output fixed frequency signal is controlled, the signal detection unit receives the signal sent by the signal generation unit and sends the signal to the control unit for processing, and the control unit calculates the motor rotating speed by counting the number of signal cycles in a certain period. In the technical scheme, the external signal is used for rotating speed calculation, the problems of unstable or inaccurate signal acquisition are avoided, and the accurate detection of the motor rotating speed is realized by counting the number of signal cycles in a certain period.

Description

Technical Field

[0001] This application relates to the field of motor speed detection technology, and in particular to a motor speed measuring device. Background Technology

[0002] As a common moving part, the electric motor is widely used in various industries. Accurate measurement of the rotational speed allows workers to understand the operating status of the motor and its power output.

[0003] Currently, motor speed measurement typically involves mounting sensors on the motor shaft or connecting them in series with a coupling. These sensors collect photoelectric or electromagnetic signals, which are then analyzed using a microcontroller to measure the motor's rotational speed. However, when using sensors for data acquisition, the data obtained from different sensors may not be stable or accurate due to variations in sensor performance.

[0004] Therefore, how to accurately detect the motor speed is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this application is to provide a motor speed measuring device to avoid inaccurate data acquisition caused by different types of sensors, and to achieve accurate detection of motor speed.

[0006] To solve the above-mentioned technical problems, this application provides a motor speed measuring device, comprising:

[0007] Signal generation unit, signal detection unit, control unit;

[0008] The signal generation unit uses a solid-state source as a signal emitting device to emit a signal at a fixed frequency; the signal includes a positive voltage signal and / or a reverse voltage signal.

[0009] The signal detection unit is connected to the control unit to send the detected signal emitted by the signal generation unit to the control unit for processing;

[0010] The control unit is used to calculate the motor speed based on the number of cycles of the signal received within a preset time.

[0011] Preferably, the signal generation unit further includes a temperature detection device for detecting the temperature of the solid-state source;

[0012] Correspondingly, the signal emitted by the signal generation unit also includes a solid-state source temperature signal;

[0013] Furthermore, when the control unit detects that the temperature of the solid-state source exceeds a threshold, it stops the output of the solid-state source.

[0014] Preferably, after the control unit receives the positive voltage signal and the reverse voltage signal emitted by the signal generation unit, it further includes:

[0015] The standing wave ratio is calculated using the forward voltage signal and the reverse voltage signal;

[0016] The output of the solid-state source is stopped when the standing wave ratio is greater than a set value.

[0017] Preferably, the temperature detection device includes a temperature sensor and a temperature detection circuit;

[0018] The solid-state source temperature signal collected by the temperature sensor is sent to the control unit through the temperature detection circuit;

[0019] The temperature detection circuit includes: a first diode, a second diode, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a first capacitor, a second capacitor, a first operational amplifier, and a second operational amplifier;

[0020] The cathode of the first diode, the first terminal of the first capacitor, the first terminal of the first resistor, and the first terminal of the second resistor together serve as the input terminal of the temperature detection circuit, used to receive the signal sent by the temperature sensor; the anode of the first diode is grounded; the second terminal of the first capacitor is grounded; the second terminal of the first resistor and the first terminal of the third resistor are connected to the first power supply; the second terminal of the third resistor is connected to the first terminal of the fourth resistor and the first terminal of the fifth resistor; the second terminal of the fourth resistor is grounded; the second terminal of the fifth resistor is connected to the inverting input terminal of the first operational amplifier and the first terminal of the sixth resistor; the second terminal of the second resistor is connected to the non-inverting input terminal of the first operational amplifier and the first terminal of the seventh resistor; the second terminal of the seventh resistor is grounded; the output terminal of the first operational amplifier is connected to the second terminal of the sixth resistor and the non-inverting input terminal of the second operational amplifier; the output terminal of the second operational amplifier is connected to the inverting input terminal of the second operational amplifier and the first terminal of the eighth resistor; the second terminal of the eighth resistor, the first terminal of the second capacitor, and the anode of the second diode together serve as the output terminal of the temperature detection circuit and are connected to the control unit; the second terminal of the second capacitor is grounded; the cathode of the second diode is connected to the second power supply.

[0021] Preferably, it further includes: a tuning unit, used as an access point for the output signal of the signal generation unit, adjusting the signal and feeding it back to the signal detection unit;

[0022] Correspondingly, the tuning unit includes an air capacitor and an inductor coil; by adjusting the matching of the air capacitor and the inductor coil, the signal collected by the signal detection unit can achieve maximum transmission efficiency.

[0023] Preferably, the adjustment method for adjusting the tuning unit to achieve maximum transmission efficiency of the signal acquired by the signal detection unit includes:

[0024] Based on the positive voltage signal V1 and the reverse voltage signal V2 fed back by the solid-state source, calculate the reverse coefficient k = V2 / V1;

[0025] Calculate the standing wave ratio Vswr = (1+k) / (1-k);

[0026] When the standing wave ratio is at its minimum value, the tuning unit is considered to be in the optimal tuning position.

[0027] Preferably, it further includes: a filtering circuit; the filtering circuit is used to filter the signal emitted by the signal generation unit.

[0028] Preferably, the input terminal of the solid-state source is a power supply controlled by a PID algorithm to output a stable analog voltage so that the solid-state source outputs stable power.

[0029] Preferably, it further includes: a signal acquisition circuit for acquiring the analog voltage input to the solid-state source;

[0030] Furthermore, it is determined whether the simulated voltage is equal to the voltage setting value corresponding to the output power of the solid-state source;

[0031] If not, adjust the magnitude of the analog voltage so that the analog voltage is equal to the voltage setting value corresponding to the output power of the solid-state source.

[0032] Preferably, it also includes: a display unit;

[0033] The display unit is connected to the control unit to display the motor speed and the power of the solid-state source in real time.

[0034] The motor speed measuring device provided in this application includes a signal generation unit, a signal detection unit, and a control unit. The signal generation unit uses a solid-state source as a signal emitting device to emit a signal at a fixed frequency. The signal includes a forward voltage signal and / or a reverse voltage signal. The signal detection unit is connected to the control unit to send the detected signal emitted by the signal generation unit to the control unit for processing. The control unit calculates the motor speed based on the number of signal cycles received within a preset time. Compared to current technologies, where signals acquired by different types of sensors may be unstable or inaccurate, this technical solution uses an additional signal generation unit as a signal emitting device, controlling its output of a signal at a fixed frequency. The signal detection unit receives the signal emitted by the signal generation unit and sends it to the control unit for processing.

[0035] The control unit calculates the motor speed by counting the number of signal cycles within a certain period. This technical solution uses an external signal for speed calculation, avoiding the problems of unstable or inaccurate signal acquisition. By calculating the number of signal cycles within a certain period, accurate detection of motor speed is achieved. Attached Figure Description

[0036] To more clearly illustrate the embodiments of this application, the accompanying 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.

[0037] Figure 1 A structural diagram of a motor speed measuring device provided in an embodiment of this application;

[0038] Figure 2 This is a circuit diagram of a temperature detection circuit provided in an embodiment of this application. Detailed Implementation

[0039] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this application.

[0040] The core of this application is to provide a motor speed measuring device to avoid inaccurate data collection caused by different types of sensors, thereby achieving accurate detection of motor speed.

[0041] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] Figure 1 A structural diagram of a motor speed measuring device provided in an embodiment of this application is shown below. Figure 1 As shown, the motor speed measuring device includes:

[0043] Signal generation unit 10, signal detection unit 11, control unit 12;

[0044] The signal generation unit 10 uses a solid-state source as a signal emitting device to emit a signal at a fixed frequency; the signal includes a positive voltage signal and / or a reverse voltage signal.

[0045] The signal detection unit 11 is connected to the control unit 12 to send the signal generated by the detected signal generation unit 10 to the control unit 12 for processing;

[0046] The control unit 12 is used to calculate the motor speed based on the number of cycles of the signal received within a preset time.

[0047] First, it should be noted that, unlike the current technology which uses sensors directly mounted on the motor shaft for signal detection, this technical solution applies a signal to the outside of the motor, uses a signal detection unit 11 to receive the signal, and sends it to the control unit 12. The control unit 12 calculates the motor speed based on the number of cycles of the received signal within a preset time. In specific implementation, the control unit 12 can be a microcontroller.

[0048] In this technical solution, the signal generation unit 10 serves as a signal emitting device. To obtain a stable signal, a solid-state source is used in this embodiment to emit a signal at a fixed frequency. In specific implementations, the solid-state source can be a shortwave signal generator. This technical solution primarily calculates the motor speed by counting the number of cycles of the received signal within a preset time. In this embodiment, the signal detection unit 11 receives the signal emitted by the signal generation unit 10. In specific implementations, the signal detection unit 11 can be a circuit matched to the feedback signal from the solid-state source, enabling the acquisition of either the positive or reverse voltage signal fed back from the solid-state source. It can use a coupler in conjunction with a current-limiting resistor to acquire the voltage. The solid-state source mainly feeds back a positive voltage signal and / or a reverse voltage signal. It can be understood that the motor speed can be measured by counting the number of cycles of either the positive or reverse voltage signal.

[0049] Specifically, the number of cycles can be calculated by detecting the number of peaks generated. For example, a positive voltage signal provided by a solid-state source can be used to detect the number of times the peaks appear. Each time a peak appears, it is considered that the motor has rotated one revolution.

[0050] The motor speed measuring device provided in this application includes a signal generation unit, a signal detection unit, and a control unit. The signal generation unit uses a solid-state source as a signal emitting device to emit a signal at a fixed frequency. The signal includes a forward voltage signal and / or a reverse voltage signal. The signal detection unit is connected to the control unit to send the detected signal emitted by the signal generation unit to the control unit for processing. The control unit calculates the motor speed based on the number of signal cycles received within a preset time. Compared to current technologies, where signals acquired by different types of sensors may be unstable or inaccurate, this technical solution uses an additional signal generation unit as a signal emitting device to control its output of a signal at a fixed frequency. The signal detection unit receives the signal emitted by the signal generation unit and sends it to the control unit for processing. The control unit calculates the motor speed based on the number of signal cycles within a certain period. This technical solution uses an external signal for speed calculation, avoiding the problem of unstable or inaccurate signal acquisition. By calculating the number of signal cycles within a certain time, accurate detection of the motor speed is achieved.

[0051] In a specific implementation, the solid-state source is used as a signal transmitting device. Long-term or high-power operation, as well as the temperature of the working environment, will cause the solid-state source to reach high temperature, which will damage the solid-state source. In order to avoid damage to the solid-state source, in this embodiment, the signal generating unit also includes a temperature detection device for detecting the temperature of the solid-state source.

[0052] Correspondingly, the signals emitted by the signal generation unit also include solid-state source temperature signals;

[0053] Furthermore, the control unit stops the output of the solid-state source when it detects that the temperature of the solid-state source exceeds the threshold.

[0054] It should be noted that some existing solid-state sources may contain temperature sensors for temperature detection. Therefore, the temperature detection device in this embodiment can be located either within the solid-state source or outside the signal generation unit. In this embodiment, when the temperature of the solid-state source exceeds a threshold, the output of the solid-state source is stopped to ensure that its output power is zero, thereby reducing damage to the solid-state source.

[0055] Based on the above embodiments, in order to further avoid damage caused by excessive use of the solid-state source, this embodiment further includes, after the control unit receives the positive voltage signal and the reverse voltage signal from the signal generation unit:

[0056] The standing wave ratio is calculated using forward and reverse voltage signals;

[0057] The solid-state source output is stopped when the VSWR is greater than the set value.

[0058] As can be seen, this embodiment calculates the output state of the solid-state source and adjusts the output of the solid-state source by changing the standing wave ratio, thereby avoiding overuse of the solid-state source.

[0059] The above embodiments describe a temperature detection device that can be located within a solid-state source or, externally within a signal generation unit. This device collects the temperature of the solid-state source, processes the signal accordingly, and sends it to the control unit for analysis and judgment. In this embodiment, the temperature detection device includes a temperature sensor and a temperature detection circuit.

[0060] The solid-state source temperature signal collected by the temperature sensor is sent to the control unit through the temperature detection circuit;

[0061] The temperature detection circuit includes: a first diode D1, a second diode D2, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a first capacitor C1, a second capacitor C2, a first operational amplifier Q1, and a second operational amplifier Q2.

[0062] The cathode of the first diode D1, the first terminal of the first capacitor C1, the first terminal of the first resistor R1, and the first terminal of the second resistor R2 together serve as the input terminal of the temperature detection circuit, used to connect to the temperature sensor.

[0063] The transmitted signal; the anode of the first diode D1 is grounded; the second terminal of the first capacitor C1 is grounded; the second terminal of the first resistor R1 and the first terminal of the third resistor R3 are connected to the first power supply; the second terminal of the third resistor R3 is connected to the first terminal of the fourth resistor R4 and the first terminal of the fifth resistor R5; the second terminal of the fourth resistor R4 is grounded; the second terminal of the fifth resistor R5 is connected to the inverting input terminal of the first operational amplifier Q1 and the first terminal of the sixth resistor R6; the second terminal of the second resistor R2 is connected to the non-inverting input terminal of the first operational amplifier Q1 and the first terminal of the seventh resistor R7; the second terminal of the seventh resistor R7 is grounded; the output terminal of the first operational amplifier Q1 is connected to the second terminal of the sixth resistor R6 and the non-inverting input terminal of the second operational amplifier Q2; the output terminal of the second operational amplifier Q2 is connected to the inverting input terminal of the second operational amplifier Q2 and the first terminal of the eighth resistor R8; the second terminal of the eighth resistor R8, the first terminal of the second capacitor C2, and the anode of the second diode D2 together serve as the output terminal of the temperature detection circuit and are connected to the control unit; the second terminal of the second capacitor C2 is grounded; the cathode of the second diode D2 is connected to the second power supply.

[0064] Figure 2This is a circuit diagram of a temperature detection circuit provided in an embodiment of this application. The circuit performs RC filtering and operational amplification on the signal emitted by the temperature sensor before outputting it to the control unit. P5 is the input port of the temperature sensor. In addition to the structure shown above, the temperature detection circuit also includes a power supply and capacitors connected to the operational amplifier, which are related to the power supply method selected for the operational amplifier and are not further limited.

[0065] It is understandable that a portion of the signal output by the solid-state source will be fed back to the solid-state source, resulting in no maximum output power. When the signal fed back to the solid-state source exceeds a certain value, it may damage the solid-state source. Therefore, it is necessary to tune the output signal of the solid-state source to ensure that the output signal of the solid-state source can be output at a large value.

[0066] Therefore, in this embodiment, the motor speed measuring device further includes: a tuning unit, which serves as an access point for the output signal of the signal generation unit, and adjusts the signal before feeding it back to the signal detection unit;

[0067] Correspondingly, the tuning unit includes an air capacitor and an inductor coil; by adjusting the matching of the air capacitor and the inductor coil, the signal acquired by the signal detection unit can achieve maximum transmission efficiency.

[0068] In practical implementation, the tuning unit is a tuning board, on which an air capacitor and an inductor coil are mounted. By matching the air capacitor and inductor coil, the tuning unit is positioned at the optimal tuning location, maximizing the transmission efficiency of the signal acquired by the signal detection unit. The air capacitor is connected to the motor shaft via a coupling, and the output of the signal generation unit is connected to the air capacitor, which is in turn connected to the inductor coil. When the motor rotates, the signal detection unit detects the forward and reverse voltages. The processor uses the magnitudes of the forward and reverse voltages and the standing wave ratio (VSWR) to record the data in a time sequence. By analyzing the forward or reverse voltage, the motor speed is detected.

[0069] In this embodiment, the tuning unit is used to maximize the output of the solid-state source to obtain a good waveform. Specifically, the adjustment method of the tuning unit to maximize the transmission efficiency of the signal acquired by the signal detection unit includes:

[0070] Based on the positive voltage signal V1 and the reverse voltage signal V2 fed back by the solid-state source, calculate the reverse coefficient k = V2 / V1;

[0071] Calculate the standing wave ratio Vswr = (1+k) / (1-k);

[0072] When the standing wave ratio is at its minimum, the tuning unit is considered to be in the optimal tuning position.

[0073] Based on the above embodiments, in this embodiment, the motor speed measuring device further includes: a filtering circuit; the filtering circuit is used to filter the signal emitted by the signal generation unit.

[0074] The filtering circuit in this embodiment is used to physically filter the signal emitted by the signal generation unit. This circuit is similar to a conventional circuit and can be implemented using capacitors, resistors, etc. In a specific implementation, the control unit can also perform software filtering again after receiving the signal.

[0075] As described in the above embodiments, accurate detection of motor speed requires a stable signal output from the solid-state source. Therefore, in this embodiment, the input terminal of the solid-state source is a power supply controlled by a PID algorithm to output a stable analog voltage so that the solid-state source outputs stable power.

[0076] Specifically, in order to achieve PID control, the motor speed measuring device also includes: a signal acquisition circuit, used to acquire the analog voltage input to the solid-state source;

[0077] Furthermore, it is determined whether the analog voltage is equal to the voltage setting value corresponding to the output power of the solid-state source;

[0078] If not, adjust the analog voltage to make it equal to the voltage setting corresponding to the output power of the solid-state source.

[0079] Based on the above embodiments, in this embodiment, the motor speed measuring device further includes: a display unit; the display unit is connected to the control unit to display the motor speed and the power of the solid-state source in real time.

[0080] In practical implementation, the display unit can be a human-machine interaction unit. The display screen can be connected to the 232 serial port control unit. Technicians can not only view the motor speed and the power of the solid-state source, but also set the speed measurement process.

[0081] For example, motor speed measurement includes two modes: manual mode and automatic mode. In manual mode, the user sets the output power of the solid-state source through the display screen, and the solid-state source outputs at that power to measure the motor speed. In automatic mode, the power parameter set by the user has no effect. The program will gradually increase the power to find the power point with the minimum standing wave ratio, and then measure the speed at this power point.

[0082] Specifically, the speed measurement process for the manual model is as follows: Technicians set the power parameters of the solid-state source on the display screen and click the manual start button; the control unit uses a microcontroller, which, based on the set power, controls the analog-to-digital converter (ADC) to output the corresponding analog voltage. The signal acquisition circuit acquires the analog voltage from the ADC and compares it with the set voltage value; the analog voltage output from the ADC is sent to the solid-state source, providing a stable power output; the signal detection unit acquires the forward and reverse voltage feedback from the solid-state source and performs hardware filtering on the acquired data; the microcontroller performs software filtering on the acquired forward and reverse voltages, processes the filtered data, calculates and stores the standing wave ratio (SWR), processes the forward and reverse voltage data separately, and calculates the real-time rotational speed based on the number of cycles of the acquired forward or reverse voltage within a fixed time period; the calculated rotational speed is then transmitted to the display unit.

[0083] The automatic speed measurement process is as follows: Without setting parameters on the screen, simply click the automatic detection button. First, set the solid-state source power range to 10W. The microcontroller controls the analog-to-digital converter (ADC) to output analog voltage. The signal acquisition unit acquires the analog voltage from the ADC and compares it with the set voltage value. The analog voltage output from the ADC is sent to the solid-state source, providing a stable power output. The signal detection unit acquires the forward and reverse voltage feedback from the solid-state source and performs hardware filtering on the acquired data. The microcontroller performs software filtering on the acquired forward and reverse voltages, processes the filtered data, calculates and stores the standing wave ratio (SWR), and calculates the real-time speed based on the number of cycles of the acquired forward or reverse voltage within a fixed time period. The solid-state source power is then adjusted sequentially to 20W, 30W, and 40W, and the above steps are repeated. The stored SWR is compared, the minimum SWR is found, and this power is used as the control parameter for speed measurement. The calculated value is then transmitted to the screen.

[0084] The voltage setting value mentioned in the above embodiments is based on the power output of the solid-state source. For example, if the power setting is 10W, the corresponding control voltage setting value should be 0.5V. The analog voltage acquired by the signal acquisition unit should also be 0.5V. In practice, it is determined whether the acquired analog voltage is 0.5V. If it is less than 0.5V, the analog voltage output from the digital-to-analog converter is increased until the acquired voltage is approximately 0.5V. When the acquired analog voltage is greater than 0.5V, the analog voltage output from the digital-to-analog converter is decreased until the acquired voltage is approximately 0.5V. This ensures the stability of the solid-state source's output signal.

[0085] The motor speed measuring device provided in this application has been described in detail above. The various embodiments in the specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to in the method section. It should be noted that those skilled in the art can make several improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

[0086] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A motor speed measuring device, characterized in that, include: Signal generation unit, signal detection unit, control unit, temperature detection device, tuning unit; The signal generation unit uses a solid-state source as a signal emitting device to emit a signal at a fixed frequency; the signal includes a positive voltage signal and / or a reverse voltage signal, as well as a solid-state source temperature signal. The temperature detection device is used to detect the temperature of the solid-state source; The signal detection unit is connected to the control unit to send the detected signal emitted by the signal generation unit to the control unit for processing; The control unit is used to calculate the motor speed based on the number of cycles of the signal received within a preset time; and to stop the output of the solid-state source when the temperature of the solid-state source exceeds the threshold. The method further includes, after the control unit receives the positive voltage signal and the reverse voltage signal emitted by the signal generation unit: The standing wave ratio is calculated using the forward voltage signal and the reverse voltage signal; The output of the solid-state source is stopped when the standing wave ratio is greater than a set value. The tuning unit is used as an access point for the output signal of the signal generation unit, and adjusts the signal before feeding it back to the signal detection unit; The tuning unit includes an air capacitor and an inductor coil; by adjusting the matching of the air capacitor and the inductor coil, the signal collected by the signal detection unit can achieve maximum transmission efficiency. The adjustment method for adjusting the tuning unit to achieve maximum transmission efficiency of the signal acquired by the signal detection unit includes: Based on the positive voltage signal V1 and the reverse voltage signal V2 fed back by the solid-state source, calculate the reverse coefficient k = V2 / V1; Calculate the standing wave ratio Vswr = (1+k) / (1-k); When the standing wave ratio is at its minimum value, it is considered that the signal collected by the signal detection unit has reached its maximum transmission efficiency.

2. The motor speed measuring device according to claim 1, characterized in that, The temperature detection device includes a temperature sensor and a temperature detection circuit; The solid-state source temperature signal collected by the temperature sensor is sent to the control unit through the temperature detection circuit; The temperature detection circuit includes: a first diode, a second diode, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a first capacitor, a second capacitor, a first operational amplifier, and a second operational amplifier; The cathode of the first diode, the first terminal of the first capacitor, the first terminal of the first resistor, and the first terminal of the second resistor together serve as the input terminal of the temperature detection circuit, used to receive the signal sent by the temperature sensor; the anode of the first diode is grounded; the second terminal of the first capacitor is grounded; the second terminal of the first resistor and the first terminal of the third resistor are connected to the first power supply; the second terminal of the third resistor is connected to the first terminal of the fourth resistor and the first terminal of the fifth resistor; the second terminal of the fourth resistor is grounded; the second terminal of the fifth resistor is connected to the inverting input terminal of the first operational amplifier and the first terminal of the sixth resistor; the second terminal of the second resistor is connected to the non-inverting input terminal of the first operational amplifier and the first terminal of the seventh resistor; the second terminal of the seventh resistor is grounded; the output terminal of the first operational amplifier is connected to the second terminal of the sixth resistor and the non-inverting input terminal of the second operational amplifier; the output terminal of the second operational amplifier is connected to the inverting input terminal of the second operational amplifier and the first terminal of the eighth resistor; the second terminal of the eighth resistor, the first terminal of the second capacitor, and the anode of the second diode together serve as the output terminal of the temperature detection circuit and are connected to the control unit; the second terminal of the second capacitor is grounded; the cathode of the second diode is connected to the second power supply.

3. The motor speed measuring device according to claim 1 or 2, characterized in that, Also includes: Filtering circuit; The filtering circuit is used to filter the signal emitted by the signal generation unit.

4. The motor speed measuring device according to claim 1, characterized in that, The input terminal of the solid-state source is a power supply controlled by a PID algorithm to output a stable analog voltage so that the solid-state source outputs stable power.

5. The motor speed measuring device according to claim 4, characterized in that, Also includes: A signal acquisition circuit is used to acquire the analog voltage input to the solid-state source; Furthermore, it is determined whether the simulated voltage is equal to the voltage setting value corresponding to the output power of the solid-state source; If not, adjust the magnitude of the analog voltage so that the analog voltage is equal to the voltage setting value corresponding to the output power of the solid-state source.

6. The motor speed measuring device according to claim 1, characterized in that, Also includes: Display unit; The display unit is connected to the control unit to display the motor speed and the power of the solid-state source in real time.

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