CN110988381B - Method and device for detecting rotating speed of direct current motor - Google Patents
Method and device for detecting rotating speed of direct current motor Download PDFInfo
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- G01P3/00—Measuring linear or angular speed; Measuring differences of linear or angular speeds
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- G01P3/44—Devices characterised by the use of electric or magnetic means for measuring angular speed
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Abstract
The invention belongs to the technical field of direct current motors, and particularly relates to a direct current motor rotating speed detection method and a direct current motor rotating speed detection device, wherein the direct current motor rotating speed detection method comprises the steps of obtaining bus current of a direct current motor, and converting the bus current into a first voltage signal; amplifying the first voltage signal to obtain a first amplified signal; filtering and converting the first amplified signal to obtain a square wave signal; and calculating the rotating speed value of the direct current motor according to the square wave signal. According to the invention, the bus current of the direct current motor is firstly obtained, the bus current is converted into a first voltage signal, the first voltage signal is amplified to obtain a first amplified signal, then the first amplified signal is filtered and converted to obtain a square wave signal, and finally the rotating speed value of the direct current motor is calculated according to the square wave signal, so that the problem that the rotating speed is easily interfered by the outside when a Hall sensor is adopted to measure the rotating speed is avoided, and the accuracy and the stability of rotating speed measurement are ensured.
Description
Technical Field
The invention belongs to the technical field of direct current motors, and particularly relates to a method and a device for detecting the rotating speed of a direct current motor.
Background
The dc motor includes a brushless dc motor and a brush dc motor. The brushless direct current motor is more and more applied to various industries due to the characteristics of high efficiency, low noise, long service life, simple assembly structure and the like.
When the direct current motor is used, the rotating speed of the direct current motor needs to be detected. In the traditional speed measurement method, a Hall sensor is mostly adopted, and a rotor magnetic field is induced by the Hall sensor and then converted into the rotating speed of the motor. However, in this way, a hall sensor needs to be added to the motor, and the installation position of the hall needs to be reserved in the mechanical structure, so that the assembly difficulty is increased, and the installation cost is increased. In addition, the accuracy of speed measurement of the hall sensor is extremely easy to be influenced due to the need of sensing a magnetic field of the rotor, and the stability and the accuracy of the rotation speed measurement can be ensured only by a specific installation position. Therefore, the rotating speed is inaccurate to measure, great trouble is brought to use, and the working efficiency is reduced.
Disclosure of Invention
The invention aims to provide a method and a device for detecting the rotating speed of a direct current motor, and aims to solve the technical problems that the direct current motor is easily interfered by the outside when measured by a Hall sensor in the prior art, so that the measurement is not accurate and the measurement result is not stable.
In order to achieve the above object, an embodiment of the present invention provides a method for detecting a rotational speed of a dc motor, including:
acquiring bus current of a direct current motor, and converting the bus current into a first voltage signal;
amplifying the first voltage signal to obtain a first amplified signal;
filtering and converting the first amplified signal to obtain a square wave signal;
and calculating the rotating speed value of the direct current motor according to the square wave signal.
Optionally, the step of performing filtering conversion processing on the first amplified signal to obtain a square wave signal includes:
simultaneously performing first filtering processing and second filtering processing on the first amplified signal to respectively obtain a first filtered signal and a second filtered signal;
and comparing the first filtering signal with the second filtering signal to obtain the square wave signal.
Optionally, the first filtering process is:
and filtering the first amplified signal through a preset first filter circuit to obtain the first filtered signal, wherein the first filter circuit has a preset first filter coefficient.
Optionally, the second filtering process is:
and filtering the first amplified signal through a preset second filter circuit to obtain a second filtered signal, wherein the second filter circuit has a preset second filter coefficient.
Optionally, the first filter coefficient is smaller than the second filter coefficient, or the second filter coefficient is smaller than the first filter coefficient.
Optionally, the step of comparing the first filtered signal and the second filtered signal to obtain the square wave signal includes:
converting the first filtered signal and the second filtered signal into the square wave signal by a comparator; wherein the content of the first and second substances,
the first filtered signal is input through the inverting input terminal of the amplifier, and the second filtered signal is input through the non-inverting input terminal of the amplifier.
Optionally, the step of converting the bus current into a first voltage signal is:
and converting the bus current into the first voltage signal through a current sampling resistor.
Optionally, the step of amplifying the first voltage signal to obtain a first amplified signal includes:
and amplifying the first voltage signal through an amplifier to obtain the first amplified signal.
Optionally, the calculation formula for calculating the rotation speed value of the dc motor according to the square wave signal is as follows:
wherein n is the rotating speed value of the direct current motor; i is the fluctuation period number of the bus current when different direct current motors rotate for one circle; and T is the period of the square wave signal.
One or more technical solutions in the method for detecting the rotating speed of the direct current motor provided by the embodiment of the invention have at least one of the following technical effects: according to the invention, the bus current of the direct current motor is firstly obtained, the bus current is converted into a first voltage signal, the first voltage signal is amplified to obtain a first amplified signal, then the first amplified signal is filtered and converted to obtain a square wave signal, and finally the rotating speed value of the direct current motor is calculated according to the square wave signal, so that the problem that the rotating speed is easily interfered by the outside when a Hall sensor is adopted to measure the rotating speed is avoided, and the accuracy and the stability of rotating speed measurement are ensured.
In order to achieve the above object, an embodiment of the present invention provides a dc motor rotation speed detection apparatus, including:
the acquisition and conversion module is used for acquiring bus current of the direct current motor and converting the bus current into a first voltage signal;
the amplifying module is used for amplifying the first voltage signal to obtain a first amplified signal;
the filtering conversion module is used for carrying out filtering conversion processing on the first amplified signal to obtain a square wave signal;
and the calculation module is used for calculating the rotating speed value of the direct current motor according to the square wave signal.
One or more technical solutions in the dc motor rotation speed detection apparatus provided by the embodiment of the present invention at least have one of the following technical effects: the direct current motor rotating speed detection device obtains the bus current of the direct current motor through the obtaining and converting module and converts the bus current into a first voltage signal; amplifying the first voltage signal through an amplifying module to obtain a first amplified signal; then, the first amplified signal is subjected to filtering conversion processing through a filtering conversion module to obtain a square wave signal; and then the rotating speed value of the direct current motor is calculated through the calculating module according to the square wave signal, so that the problem that the rotating speed is easily interfered by the outside when the rotating speed is measured by adopting the Hall sensor is avoided, and the accuracy and the stability of rotating speed measurement are ensured.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.
Fig. 1 is a flowchart of a method for detecting a rotational speed of a dc motor according to an embodiment of the present invention;
fig. 2 is a flowchart of step S1003 in the method for detecting a rotational speed of a dc motor according to the embodiment of the present invention;
fig. 3 is a block diagram of a structure of a dc motor rotation speed detection apparatus according to an embodiment of the present invention;
fig. 4 is a block diagram of a dc motor rotation speed detection apparatus according to another embodiment of the present invention;
fig. 5 is a circuit block diagram of a filter conversion circuit of the dc motor rotation speed detection apparatus according to the embodiment of the present invention;
fig. 6 is a schematic circuit diagram of a dc motor rotation speed detection apparatus according to another embodiment of the present invention;
fig. 7 is a simplified schematic diagram of the conversion of the first amplified signal, the first filtered signal, the second filtered signal and the square wave signal according to the embodiment of the present invention.
Wherein, in the figures, the respective reference numerals:
the device 100 for detecting the rotating speed of the direct current motor comprises an acquisition conversion module 110, an amplification module 120, a filtering conversion module 130 and a calculation module 140.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary and intended to be illustrative of the embodiments of the present invention, and should not be construed as limiting the invention.
In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.
It will be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It should also be understood that the term "and/or" as used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.
As used in this specification and the appended claims, the term "if" may be interpreted contextually as "when", "upon" or "in response to" determining "or" in response to detecting ". Similarly, the phrase "if it is determined" or "if a [ described condition or event ] is detected" may be interpreted contextually to mean "upon determining" or "in response to determining" or "upon detecting [ described condition or event ]" or "in response to detecting [ described condition or event ]".
Furthermore, in the description of the present application and the appended claims, the terms "first," "second," "third," and the like are used for distinguishing between descriptions and not necessarily for describing or implying relative importance.
Reference throughout this specification to "one embodiment" or "some embodiments," or the like, means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the present application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," or the like, in various places throughout this specification are not necessarily all referring to the same embodiment, but rather "one or more but not all embodiments" unless specifically stated otherwise. The terms "comprising," "including," "having," and variations thereof mean "including, but not limited to," unless expressly specified otherwise.
In an embodiment of the present invention, as shown in fig. 1-2, a method for detecting a rotation speed of a dc motor is provided, including:
s1001: acquiring bus current of a direct current motor, and converting the bus current into a first voltage signal;
specifically, taking the brushless dc motor as an example, when the rotation speed of the brushless dc motor needs to be detected, a bus current of the brushless dc motor is obtained first, and then the bus current is converted into the first voltage signal.
S1002: amplifying the first voltage signal to obtain a first amplified signal;
in this step, the first voltage signal is amplified into a first amplified signal, so as to further process the first amplified signal.
S1003: filtering and converting the first amplified signal to obtain a square wave signal;
in this step, the first amplified signal is filtered and converted to obtain a square wave signal, so that the period of the square wave signal is conveniently obtained, and the rotating speed of the brushless direct current motor is conveniently and accurately calculated.
S1004: and calculating the rotating speed value of the direct current motor according to the square wave signal.
According to the invention, the bus current of the direct current motor is firstly obtained, the bus current is converted into a first voltage signal, the first voltage signal is amplified to obtain a first amplified signal, then the first amplified signal is filtered and converted to obtain a square wave signal, and finally the rotating speed value of the direct current motor is calculated according to the square wave signal, so that the problem that the rotating speed is easily interfered by the outside when a Hall sensor is adopted to measure the rotating speed is avoided, and the accuracy and the stability of rotating speed measurement are ensured.
Further, when the brushless direct current motor works, the waveform of the bus current changes periodically, the commutation frequency of the brushless direct current motor changes accordingly, and the periodic change frequency of the bus current and the commutation frequency of the brushless direct current motor are in a fixed proportional relation. The invention obtains the bus current by utilizing the principle and further processes the bus current to obtain the rotating speed of the brushless DC motor.
Optionally, the step of performing filtering conversion processing on the first amplified signal to obtain a square wave signal includes:
s2001: simultaneously performing first filtering processing and second filtering processing on the first amplified signal to respectively obtain a first filtered signal and a second filtered signal;
after the first filtering process and the second filtering process in this step, the first filtered signal and the second filtered signal are obtained, on one hand, the first amplified signal is filtered to remove burrs and make the signal smoother, and on the other hand, the first filtered signal and the second filtered signal are obtained, so as to further obtain a square wave signal. Wherein the periods of the first and second filtered signals are the same as the period of the bus current.
S2002: and comparing the first filtering signal with the second filtering signal to obtain the square wave signal.
In this step, the square wave signal is obtained through comparison processing, and the period of the square wave signal is the same as the periods of the first filtering signal and the second filtering signal.
Optionally, the first filtering process is:
and filtering the first amplified signal through a preset first filter circuit to obtain the first filtered signal, wherein the first filter circuit has a preset first filter coefficient. The first filter coefficient is set according to actual requirements, and the first filter coefficient can be set by setting parameters of each component in the first filter circuit. And filtering the first amplified signal by presetting the first filter coefficient so as to enable the first amplified signal to generate phase offset, and changing the amplitude of the first amplified signal so as to obtain the first filtered signal. The smaller the first filter coefficient, the smaller the phase offset of the first amplified signal, and the smaller the amplitude change.
Optionally, the second filtering process is:
and filtering the first amplified signal through a preset second filter circuit to obtain a second filtered signal, wherein the second filter circuit has a preset second filter coefficient. The second filter coefficient is set according to actual requirements, and the second filter coefficient can be set by setting parameters of each component in the second filter circuit. And filtering the first amplified signal by presetting the second filter coefficient so as to enable the first amplified signal to generate phase offset, and changing the amplitude of the first amplified signal so as to obtain the second filtered signal.
Optionally, the first filter coefficient is smaller than the second filter coefficient, or the second filter coefficient is smaller than the first filter coefficient. Specifically, when the first filter coefficient is smaller than the second filter coefficient, the phase offset of the first filter signal is smaller than the phase offset of the second filter coefficient, and the amplitude variation of the first filter signal is smaller than the amplitude variation of the second filter coefficient. When the first filter coefficient is larger than the second filter coefficient, the phase offset of the first filter signal is larger than the phase offset of the second filter coefficient, and the amplitude change of the first filter signal is larger than the amplitude change of the second filter coefficient.
Optionally, the step of comparing the first filtered signal and the second filtered signal to obtain the square wave signal includes:
converting the first filtered signal and the second filtered signal into the square wave signal by a comparator; wherein the content of the first and second substances,
the first filtered signal is input through the inverting input terminal of the amplifier, and the second filtered signal is input through the non-inverting input terminal of the amplifier. In this way, the first filtered signal and the second filtered signal are compared by the comparator to obtain the square wave signal. And compared with the first filtering signal and the second filtering signal, the period of the square wave signal is easier to obtain according to the square wave signal, so that the rotating speed of the brushless direct current motor is further calculated.
Alternatively, the first filtered signal may be input through a non-inverting input terminal of the amplifier, and the second filtered signal may be input through an inverting input terminal of the amplifier.
Optionally, the step of converting the bus current into a first voltage signal is:
and converting the bus current into the first voltage signal through a current sampling resistor. Particularly, the bus current is converted into the first voltage signal by adopting the current sampling resistor, so that the production cost is greatly reduced. In hardware cost, only one current sampling resistor needs to be arranged, convenience and rapidness are achieved, and stability is high.
Optionally, the step of amplifying the first voltage signal to obtain a first amplified signal includes:
and amplifying the first voltage signal through an amplifier to obtain the first amplified signal.
Specifically, the first voltage signal is amplified by the amplifier to obtain the first amplified signal, so as to further process the first amplified signal. The selection of the amplifier is set by a person skilled in the art according to actual requirements, and the invention is not limited in particular.
Further, the formula for calculating the rotation speed value of the dc motor according to the square wave signal is as follows:
wherein n is the rotating speed value of the direct current motor; i is the fluctuation period number of the bus current when different direct current motors rotate for one circle; and T is the period of the square wave signal.
In particular, the method for measuring the rotation speed of the direct current motor can be applied to different motors. For example, when the speed measurement is carried out on the brushless DC water pump with three phases and two opposite poles,when the bus rotates for each circle, the fluctuation period number of the bus current is 12 times, so that the value of i is 12, and the measured actual rotating speed calculation formula is as follows:
when the speed of the two-phase two-antipode brushless direct current water pump is measured, the fluctuation period number of the bus current is 4 times when the two-phase two-antipode brushless direct current water pump rotates for one circle, so that the value of i is 4, and the measured actual rotating speed calculation formula is as follows:
of course, the method for measuring the rotating speed of the direct current motor is not limited to measuring the speed of the brushless direct current water pump with the three-phase two-antipode and the two-phase two-antipode, and can also measure the speed of other types of water pumps, which is not listed in the invention.
In another embodiment of the present invention, as shown in fig. 3, there is also provided a dc motor rotation speed detecting apparatus 100, which includes an obtaining and converting module 110, an amplifying module 120, a filtering and converting module 130, and a calculating module 140.
The acquisition and conversion module 110 is configured to acquire a bus current of the dc motor and convert the bus current into a first voltage signal.
The amplifying module 120 is configured to amplify the first voltage signal to obtain a first amplified signal.
And a filtering and converting module 130, configured to perform filtering and converting processing on the first amplified signal to obtain a square wave signal.
And the calculating module 140 is configured to calculate a rotation speed value of the dc motor according to the square wave signal.
In another embodiment of the present invention, as shown in fig. 4-7, the dc motor speed detection apparatus is applied to a brushless dc motor, wherein the dc motor speed detection apparatus includes a current sampling circuit 111, an amplifier circuit 121, a filter converting circuit 131 and a square wave calculating module 141.
The current sampling circuit 111 is configured to obtain a bus current of the dc motor, and convert the bus current into a first voltage signal.
Specifically, the current sampling circuit 111 includes a current sampling resistor R9. Taking a brushless dc motor as an example, the brushless dc motor is powered by a power supply, a positive power supply end of the power supply is connected to a positive power supply line of the brushless dc motor, a negative power supply line of the brushless dc motor is connected to one end S + of the current sampling resistor R9, and the other end S-of the current sampling resistor R9 is connected to a negative power supply end of the power supply.
When the brushless direct current motor works, the current of the power supply sequentially passes through the brushless direct current motor and the current sampling resistor R9, so that the current sampling resistor R9 collects the bus current of the brushless direct current motor, and the bus current is converted into the first voltage signal by the current sampling resistor R9.
The amplifier circuit 121 is configured to amplify the first voltage signal to obtain a first amplified signal I. The amplifier circuit is connected with the current sampling circuit.
Specifically, the amplifier circuit 121 includes a first operational amplifier U1, a non-inverting input terminal of the first operational amplifier U1 is connected to one end S + of the current sampling resistor R9, and an inverting input terminal of the first operational amplifier U1 is connected to the other end S-of the current sampling resistor R9.
In order to prevent the first operational amplifier U1 from being damaged by excessive current, the non-inverting input terminal of the first operational amplifier U1 is further connected to one end of an eighth current-limiting resistor R8, the other end of the eighth current-limiting resistor R8 is further connected to one end S + of the current sampling resistor R9, the inverting input terminal of the first operational amplifier U1 is further connected to one end of a seventh current-limiting resistor R7, and the other end of the seventh current-limiting resistor R7 is further connected to the other end S-of the current sampling resistor R9. A fifth capacitor C5 is connected in parallel between the eighth current limiting resistor R8 and the seventh current limiting resistor R7, and the fifth capacitor C5 plays a role of filtering.
The inverting input terminal of the first operational amplifier U1 is further connected to a fifth resistor R5, and the other terminal of the fifth resistor R5 is connected to the output terminal of the first operational amplifier U1. The non-inverting input terminal of the first operational amplifier U1 is further connected to one end of a sixth resistor R6, and the other end of the sixth resistor R6 is grounded.
As shown in fig. 5-7, the first voltage signal is amplified by the first operational amplifier U1 to become the first amplified signal I, and is output from the output terminal of the first operational amplifier U1 to the filtering and converting circuit.
The filtering and converting circuit 131 is configured to perform filtering and converting processing on the first amplified signal I to obtain a square wave signal I _ O. The filter conversion circuit is connected to the amplifier circuit 121.
Specifically, the filter conversion circuit 131 includes a filter circuit 1311 and a comparator conversion circuit 1312. The filter circuit 1311 includes a first filter circuit 1313 and a second filter circuit 1314, and the first filter circuit 1313 and the second filter circuit 1314 are both connected to an output terminal of the first operational amplifier U1.
The first filter circuit 1313 includes a second resistor R2 and a second capacitor C2, the second resistor R2 is connected to the output terminal of the first operational amplifier U1, and the second capacitor C2 is connected to the second resistor R2.
The second filter circuit 1314 includes a third resistor R3 and a fourth capacitor C4, the third resistor R3 is connected to the output terminal of the first operational amplifier U1, and the fourth capacitor C4 is connected to the third resistor R3.
The first amplified signal I is filtered by the first filter circuit 1313 and the second filter circuit 1314, and the first filtered signal I _ N is output from the first filter circuit 1313, and the second filtered signal I _ P is output from the second filter circuit.
The comparator converting circuit 1312 is connected to both the first filter circuit 1313 and the second filter circuit 1314.
Specifically, the comparator switching circuit 1312 includes a second operational amplifier U2, a first capacitor C1, and a first resistor R1. The non-inverting input terminal of the second operational amplifier U2 is connected to the fourth capacitor C4, and the inverting input terminal of the second operational amplifier U2 is connected to the second capacitor C2. The inverting input end of the second operational amplifier U2 is connected to one end of the first capacitor C1, the other end of the first capacitor C1 is connected to the first resistor R1, and the first resistor R1 is further connected to the output end of the second operational amplifier U2.
The first filtered signal I _ N and the second filtered signal I _ P are respectively input through the inverting input terminal and the non-inverting input terminal of the second operational amplifier U2, and are converted into the square wave signal I _ O by the second operational amplifier U2 and output to the computing module 141 through the output terminal of the second operational amplifier U2.
The square wave calculating module 141 is configured to calculate a rotation speed value of the dc motor according to the square wave signal I _ O. Specifically, the calculation module can adopt an 8-bit single chip microcomputer to realize the required functions. Such as an 80C51 singlechip.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (9)
1. A method for detecting the rotating speed of a direct current motor is characterized by comprising the following steps:
acquiring bus current of a direct current motor, and converting the bus current into a first voltage signal;
amplifying the first voltage signal to obtain a first amplified signal;
filtering and converting the first amplified signal to obtain a square wave signal;
calculating the rotating speed value of the direct current motor according to the square wave signal;
wherein, the step of performing filtering conversion processing on the first amplified signal to obtain a square wave signal comprises:
simultaneously performing first filtering processing and second filtering processing on the first amplified signal to respectively obtain a first filtered signal and a second filtered signal;
comparing the first filtering signal with the second filtering signal to obtain the square wave signal;
wherein the first amplified signal is output by a first operational amplifier, the first amplified signal is filtered by a first filter circuit and a second filter circuit at the same time, the first filtered signal is output from the first filter circuit, and the second filtered signal is output from the second filter circuit;
the first filter circuit comprises a second resistor and a second capacitor, wherein a first end of the second resistor is connected with an output end of the first operational amplifier, a first end of the second capacitor is connected with a second end of the second resistor, and a second end of the second capacitor is grounded;
the second filter circuit comprises a third resistor and a fourth capacitor, wherein the first end of the third resistor is connected with the output end of the first operational amplifier, the first end of the fourth capacitor is connected with the second end of the third resistor, and the second end of the fourth capacitor is grounded.
2. The method for detecting the rotating speed of the direct current motor according to claim 1, wherein the first filtering process is:
and filtering the first amplified signal through a preset first filter circuit to obtain the first filtered signal, wherein the first filter circuit has a preset first filter coefficient.
3. The method for detecting the rotating speed of the direct current motor according to claim 2, wherein the second filtering process is:
and filtering the first amplified signal through a preset second filter circuit to obtain a second filtered signal, wherein the second filter circuit has a preset second filter coefficient.
4. The method according to claim 3, wherein the first filter coefficient is smaller than the second filter coefficient, or the second filter coefficient is smaller than the first filter coefficient.
5. The method for detecting the rotating speed of the direct current motor according to claim 1, wherein the step of comparing the first filtered signal and the second filtered signal to obtain the square wave signal comprises:
converting the first filtered signal and the second filtered signal into the square wave signal by a comparator; wherein the content of the first and second substances,
the first filtered signal is input through the inverting input terminal of the amplifier, and the second filtered signal is input through the non-inverting input terminal of the amplifier.
6. The method for detecting the rotating speed of the direct current motor according to claim 1, wherein the step of converting the bus current into the first voltage signal comprises the steps of:
and converting the bus current into the first voltage signal through a current sampling resistor.
7. The method for detecting the rotating speed of the direct current motor according to claim 1, wherein the step of amplifying the first voltage signal to obtain a first amplified signal comprises:
and amplifying the first voltage signal through an amplifier to obtain the first amplified signal.
8. The method for detecting the rotating speed of the direct current motor according to claim 1, wherein the formula for calculating the rotating speed value of the direct current motor according to the square wave signal is as follows:
wherein n is the rotating speed value of the direct current motor; i is the fluctuation period number of the bus current when different direct current motors rotate for one circle; and T is the period of the square wave signal.
9. A DC motor rotation speed detection device is characterized by comprising:
the acquisition and conversion module is used for acquiring bus current of the direct current motor and converting the bus current into a first voltage signal;
the amplifying module is used for amplifying the first voltage signal to obtain a first amplified signal;
the filtering conversion module is used for carrying out filtering conversion processing on the first amplified signal to obtain a square wave signal;
the calculation module is used for calculating the rotating speed value of the direct current motor according to the square wave signal;
wherein the filtering conversion module comprises a filtering circuit and a comparator conversion circuit,
the filter circuit is used for simultaneously carrying out first filtering processing and second filtering processing on the first amplified signal to respectively obtain a first filtered signal and a second filtered signal;
the comparator conversion circuit is used for comparing the first filtering signal and the second filtering signal to obtain the square wave signal;
the filter circuit comprises a first filter circuit and a second filter circuit;
wherein the first amplified signal is output by a first operational amplifier, the first amplified signal is filtered by a first filter circuit and a second filter circuit at the same time, the first filtered signal is output from the first filter circuit, and the second filtered signal is output from the second filter circuit;
the first filter circuit comprises a second resistor and a second capacitor, wherein a first end of the second resistor is connected with an output end of the first operational amplifier, a first end of the second capacitor is connected with a second end of the second resistor, and a second end of the second capacitor is grounded;
the second filter circuit comprises a third resistor and a fourth capacitor, wherein the first end of the third resistor is connected with the output end of the first operational amplifier, the first end of the fourth capacitor is connected with the second end of the third resistor, and the second end of the fourth capacitor is grounded.
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| CN201911316086.8A CN110988381B (en) | 2019-12-19 | 2019-12-19 | Method and device for detecting rotating speed of direct current motor |
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| CN201911316086.8A CN110988381B (en) | 2019-12-19 | 2019-12-19 | Method and device for detecting rotating speed of direct current motor |
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| CN114397470A (en) * | 2021-11-24 | 2022-04-26 | 浙江捷昌线性驱动科技股份有限公司 | Stroke control system based on motor current characteristics |
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