CN118130888A - Sampling circuit, control device and stepping motor system - Google Patents

Sampling circuit, control device and stepping motor system Download PDF

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Publication number
CN118130888A
CN118130888A CN202410558905.4A CN202410558905A CN118130888A CN 118130888 A CN118130888 A CN 118130888A CN 202410558905 A CN202410558905 A CN 202410558905A CN 118130888 A CN118130888 A CN 118130888A
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sampling
current
data
preliminary
processing unit
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CN202410558905.4A
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CN118130888B (en
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刘俊杰
陈相园
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Wuxi Indie Microelectronics Technology Co Ltd
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Wuxi Indie Microelectronics Technology Co Ltd
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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02KDYNAMO-ELECTRIC MACHINES
    • H02K11/00Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection
    • H02K11/20Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection for measuring, monitoring, testing, protecting or switching
    • H02K11/27Devices for sensing current, or actuated thereby
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/25Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
    • G01R19/2506Arrangements for conditioning or analysing measured signals, e.g. for indicating peak values ; Details concerning sampling, digitizing or waveform capturing
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/25Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
    • G01R19/2506Arrangements for conditioning or analysing measured signals, e.g. for indicating peak values ; Details concerning sampling, digitizing or waveform capturing
    • G01R19/2509Details concerning sampling, digitizing or waveform capturing
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02KDYNAMO-ELECTRIC MACHINES
    • H02K11/00Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection
    • H02K11/30Structural association with control circuits or drive circuits
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02PCONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P8/00Arrangements for controlling dynamo-electric motors rotating step by step
    • H02P8/12Control or stabilisation of current

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Control Of Stepping Motors (AREA)

Abstract

The invention discloses a sampling circuit, a control device and a stepping motor system. The sampling resistor is arranged between a lower bridge arm connecting point of a control circuit of the stepping motor and a grounding end, wherein the lower bridge arm connecting point is a connecting point between two switching devices in the lower bridge arm. The sampling processing module is respectively connected with two ends of the sampling resistor, and is used for determining a sampling comparison result according to the sampling current and a preset current under the condition that the sampling current flowing through the sampling resistor is in a positive direction, and determining the sampling comparison result according to the reverse processing data of the sampling current and the preset current under the condition that the sampling current flowing through the sampling resistor is in a negative direction, so that the current flowing through the stepping motor coil is sampled and processed, current sampling errors under a fast attenuation mode are avoided, current phase difference between two phases is accurately controlled, and motor operation noise is reduced.

Description

Sampling circuit, control device and stepping motor system
Technical Field
The present invention relates to the field of motor control, and in particular, to a sampling circuit, a control device, and a stepper motor system.
Background
The stepping motor has excellent position control performance and is suitable for application scenes requiring accurate position control. Nowadays, with the increasing demand of people for riding comfort of passenger automobiles, stepper motors are increasingly applied to automobiles, such as air conditioning air blowing ports, electric door handles and the like. There is a need for silencing a stepper motor mounted on an electric vehicle, which places a higher demand on a conventional control system.
In a stepping motor system, a digital-to-analog converter chip is often adopted to provide preset current, and then current control of the stepping motor is realized through comparison of sampling current and preset current.
However, during the process of controlling the sampled data, the sampled data is often inverted due to the fast attenuation state of the stepper motor, so that control errors are caused, which not only affect the control accuracy of the current phase, but also are the maximum sources of the noise of the stepper motor.
Disclosure of Invention
The invention provides a sampling circuit, a control device and a stepping motor system, which are used for improving the control accuracy of a two-phase current phase difference and reducing the operation noise of a stepping motor.
According to an aspect of the present invention, there is provided a sampling circuit including a sampling resistor and a sampling processing module;
The sampling resistor is arranged between a lower bridge arm connecting point and a grounding end of a control circuit of the stepping motor, wherein the lower bridge arm connecting point is a connecting point between two switching devices in a lower bridge arm;
The sampling processing module is respectively connected with two ends of the sampling resistor, and is used for determining a sampling comparison result according to the sampling current and a preset current when the sampling current flowing through the sampling resistor is in a positive direction, and determining the sampling comparison result according to the reverse processing data of the sampling current and the preset current when the sampling current flowing through the sampling resistor is in a negative direction; the reverse processing data is data obtained after the sampling current is subjected to reverse processing;
the sampling processing module specifically comprises a preliminary processing unit, a direction judging unit, a reverse processing unit and a data comparing unit;
The primary processing unit is connected with two ends of the sampling resistor and is used for acquiring the sampling current and carrying out primary operational amplification on the sampling current to generate primary sampling data;
The reverse processing unit is connected with the preliminary processing unit and is used for determining reverse sampling data of the sampling current according to the preliminary sampling data;
the direction judging unit is connected with the preliminary processing unit and is used for determining the direction of the sampling current according to the preliminary sampling data;
the data comparison unit is respectively connected with the preliminary processing unit, the reverse processing unit and the direction judging unit, and is used for generating the sampling comparison result according to the relative relation between the preliminary sampling data and the comparison data corresponding to the preset current when the sampling current is in the positive direction, and generating the sampling comparison result according to the relative relation between the reverse sampling data and the comparison data corresponding to the preset current when the sampling current is in the negative direction.
Optionally, the preliminary processing unit includes an operational amplifier, a first input end of the operational amplifier is connected with one end of the sampling resistor far away from the ground end, a second input end of the operational amplifier is connected with one end of the sampling resistor near the ground end, and the first input end is also connected with a reference potential; the output end of the operational amplifier is respectively connected with the direction judging unit, the reverse processing unit and the data comparing unit, and the operational amplifier is used for amplifying the sampling current according to the reference potential, the sampling current and the resistance value of the sampling resistor to determine the preliminary sampling data of the sampling current.
Optionally, the operational amplifier performs the amplifying operation according to a first operational formula, where the first operational formula is OUT 1=GAIN*I*R + Vref, OUT 1 is the preliminary sampling data of the sampling current, GAIN is an amplifying coefficient of the operational amplifier, I is the sampling current flowing through the sampling resistor, R is a resistance value of the sampling resistor, and V ref is a reference potential.
Optionally, the direction judging unit comprises a first comparator, a first input end of the first comparator is connected with the preliminary processing unit, and a second input end of the first comparator is connected with a reference potential; the output end of the first comparator is connected with the data comparison unit; the first comparator is used for comparing the preliminary sampling data with the reference potential, and determining the direction of the sampling current according to a comparison result.
Optionally, the inverse processing unit includes a subtractor, a first input end of the subtractor is connected with the preliminary processing unit, a second input end of the subtractor is connected with a reference potential, an output end of the subtractor is connected with the data comparing unit, and the subtractor is used for performing subtraction operation on the preliminary sampling data according to the preliminary sampling data and the reference potential, so as to determine the inverse sampling data of the sampling current.
Optionally, the subtractor performs the subtraction according to a second operation formula, where the second operation formula is OUT 3=2Vref-OUT1, OUT 3 is the reverse sampled data of the sampled current, V ref is a reference potential, and OUT 1 is the preliminary sampled data of the sampled current.
Optionally, the data comparing unit includes a multiplexing switch and a second comparator;
The multi-path selection switch comprises a first access end, a second access end, a control end and a selection result output end; the first access end is connected with the preliminary processing unit, the second access end is connected with the reverse processing unit, the control end is connected with the direction judging unit, and the multi-path selection switch is used for switching the access end connected with the selection result output end according to the direction of the sampling current accessed by the control end;
The first input end of the second comparator is connected with the selection result output end, the second input end of the second comparator is connected with comparison data corresponding to the preset current, the second comparator is used for comparing the comparison data corresponding to the preset current with the data connected with the selection result output end, and the sampling comparison result is determined according to the comparison result.
According to another aspect of the present invention, there is provided a control device of a stepping motor, the control device of the stepping motor including: a control circuit and the sampling circuit of any of the first aspects;
and a master control unit in the control circuit is connected with the sampling circuit and is used for controlling the working states of transistors in the upper bridge arm and the lower bridge arm according to the sampling comparison result provided by the sampling circuit.
According to still another aspect of the present invention, there is provided a stepping motor system including the stepping motor control device of the second aspect and a stepping motor.
The sampling circuit, the control device and the stepping motor system provided by the embodiment of the invention comprise a sampling resistor and a sampling processing module. The sampling resistor is arranged between a lower bridge arm connecting point of a control circuit of the stepping motor and a grounding end, wherein the lower bridge arm connecting point is a connecting point between two switching devices in the lower bridge arm. The sampling processing module is respectively connected with two ends of the sampling resistor, and is used for determining a sampling comparison result according to the sampling current and the preset current when the sampling current flowing through the sampling resistor is in a positive direction, and determining the sampling comparison result according to the reverse processing data of the sampling current and the preset current when the sampling current flowing through the sampling resistor is in a negative direction; the reverse processing data is data obtained by carrying out reverse processing on the sampling current, so that the current flowing through the coils of the stepping motor is sampled and processed, current sampling errors in a fast attenuation mode are avoided, the current phase difference between the two coils is accurately controlled, the phase control accuracy of the stepping motor is improved, and the running noise of the motor is reduced.
It should be understood that the description in this section is not intended to identify key or critical features of the embodiments of the invention or to delineate the scope of the invention. Other features of the present invention will become apparent from the description that follows.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic diagram of a control circuit of a stepping motor in the prior art.
Fig. 2 is a schematic diagram of two-phase preset current of a stepper motor according to the prior art.
Fig. 3 is a schematic diagram of a preset current of a stepper motor according to the prior art.
Fig. 4 is a schematic diagram of actual current flowing through a coil in a stepping motor according to the prior art.
Fig. 5 is a schematic diagram of a sampling circuit and a corresponding control circuit according to an embodiment of the present invention.
Fig. 6 is a schematic diagram of another sampling circuit according to an embodiment of the present invention.
Fig. 7 is a schematic diagram of another sampling circuit and a corresponding control circuit according to an embodiment of the present invention.
Fig. 8 is a schematic diagram of a stepper motor system according to an embodiment of the present invention.
Detailed Description
In order that those skilled in the art will better understand the present invention, a technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and the claims of the present invention and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the invention described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
As background technology, in a stepping motor system, a digital-to-analog converter chip is often adopted to provide a preset current as a control target of a motor coil, and then current control of the stepping motor is realized through comparison of a sampling current and the preset current. However, in the process of controlling the sampled data, the sampled data is often inverted due to the stepping motor entering a fast decay state. Fig. 1 is a schematic diagram of a control circuit of a stepper motor according to the prior art, and referring to fig. 1, the inventor has found that, in a driving state, a current flowing through a motor coil in the stepper motor starts from a power source to a ground terminal along a first path 101, and a current direction flowing through a sampling resistor is defined as a positive direction. In the slow decay mode, the current flowing through the motor coil in the stepper motor follows the second loop 102, and the current flowing through the sampling resistor is 0. In the fast-decay mode, the current flowing through the motor coil in the stepper motor is in the negative direction along the direction of the third path 103 to the ground terminal. Fig. 2 is a schematic diagram of two preset currents of a stepper motor in the prior art, referring to fig. 2, a phase difference of 90 ° is required between the two currents of the stepper motor, and the phase difference between the two currents is controlled to reduce vibration and noise of the stepper motor. A common control method is to compare the collected motor current with a preset DAC value (also referred to as a preset current), and control the current flowing through the coil according to the comparison result. Fig. 3 is a schematic diagram of preset current of a stepper motor in the prior art, fig. 4 is a schematic diagram of actual current flowing through a coil in a stepper motor in the prior art, and in combination with fig. 1, fig. 3 and fig. 4, since the preset current is a set sinusoidal current waveform, the current direction flowing through a sampling resistor is inverted although the coil current is not inverted in the fast decay mode, if current control is directly performed according to the difference between the sampling current and the preset current, the actual waveform of the current flowing through the corresponding coil will be as shown in fig. 4, and a control error will occur.
In order to solve the foregoing problems, an embodiment of the present invention provides a sampling circuit, which can be applied to a stepper motor for collecting and processing a current flowing through a coil. Fig. 5 is a schematic diagram of a sampling circuit and a corresponding control circuit according to an embodiment of the present invention, and referring to fig. 5, a sampling circuit 500 includes a sampling resistor R0 and a sampling processing module 501. The sampling resistor R0 is arranged between a lower bridge arm connection point A of a control circuit of the stepping motor and a ground end GND, wherein the lower bridge arm connection point A is a connection point between two switching devices in the lower bridge arm. The sampling processing module 501 is respectively connected with two ends of the sampling resistor R0, and the sampling processing module 501 is configured to determine a sampling comparison result according to the sampling current and the preset current when the sampling current flowing through the sampling resistor R0 is in a positive direction, and determine the sampling comparison result according to the reverse processing data of the sampling current and the preset current when the sampling current flowing through the sampling resistor R0 is in a negative direction; the reverse processing data is data obtained by carrying out reverse processing on the sampling current.
Specifically, the sampling current being in the positive direction means that the sampling current flows from the end of the sampling resistor R0 away from the ground terminal to the end of the sampling resistor R0 connected to the ground terminal. The negative direction of the sampling current means that the sampling current flows from one end of the sampling resistor R0 connected to the ground end to one end of the sampling resistor R0 far away from the ground end. The sampling processing module 501 is a data processing component of sampling current, and can determine the direction of the sampling current, further, according to different directions, perform different processes on the sampling current, and compare the processed data with the comparison data of the preset current to obtain a sampling comparison result, where the different processes may include at least one of operational amplification, inversion and comparison; the sampling comparison result is a judgment result representing the relative relation between the sampling data and the preset current. For example, in the case that the sampling current flowing through the sampling resistor R0 is in the positive direction, the sampling processing module 501 may perform operational amplification on the sampling current, compare the data obtained by the operational amplification on the sampling current with the data corresponding to the preset current, and output the sampling comparison result of the first level to instruct the general control unit to control the current flowing through the motor coil to decrease in the case that the sampling current is greater than the preset current, and output the sampling comparison result of the second level to instruct the general control unit to control the current flowing through the motor coil to increase in the case that the sampling current is smaller than the preset current. In the case that the sampling current flowing through the sampling resistor R0 is in the negative direction, the sampling processing module 501 may perform inverse processing and operational amplification on the sampling current, perform inverse processing on the sampling current into positive direction data, and compare the data obtained after the operational amplification with the comparison data corresponding to the preset current, and output a sampling comparison result of the second level to instruct the master control unit to control the current flowing through the motor coil to increase when the comparison result is that the sampling current is smaller than the preset current, and output a sampling comparison result of the first level to instruct the master control unit to control the current flowing through the motor coil to decrease when the comparison result is that the sampling current is larger than the preset current.
The sampling circuit provided by the embodiment comprises a sampling resistor and a sampling processing module. The sampling resistor is arranged between a lower bridge arm connecting point of a control circuit of the stepping motor and a grounding end, wherein the lower bridge arm connecting point is a connecting point between two switching devices in the lower bridge arm. The sampling processing module is respectively connected with two ends of the sampling resistor, and is used for determining a sampling comparison result according to the sampling current and the preset current when the sampling current flowing through the sampling resistor is in a positive direction, and determining the sampling comparison result according to the reverse processing data of the sampling current and the preset current when the sampling current flowing through the sampling resistor is in a negative direction; the reverse processing data is data obtained by carrying out reverse processing on the sampling current, so that the current flowing through the coils of the stepping motor is sampled and processed, current sampling errors in a fast attenuation mode are avoided, the current phase difference between the two coils is accurately controlled, the control accuracy of the stepping motor is improved, and the running noise of the motor is reduced.
Optionally, fig. 6 is a schematic diagram of another sampling circuit according to an embodiment of the present invention, and referring to fig. 6, on the basis of the foregoing embodiment, the sampling processing module 501 includes a preliminary processing unit 601, a direction judging unit 602, a reverse processing unit 603, and a data comparing unit 604. The preliminary processing unit 601 is connected with two ends of the sampling resistor R0, and the preliminary processing unit 601 is configured to obtain a sampling current and perform preliminary operational amplification processing on the sampling current, so as to generate preliminary sampling data. The reverse processing unit 603 is connected to the preliminary processing unit 601, and the reverse processing unit 603 is configured to determine reverse sampling data of the sampling current according to the preliminary sampling data. The direction judging unit 602 is connected to the preliminary processing unit 601, and is configured to determine a direction of the sampling current according to the preliminary sampling data. The data comparing unit 604 is respectively connected to the preliminary processing unit 601, the reverse processing unit 603, and the direction judging unit 602, where the data comparing unit 604 is configured to generate a sampling comparison result according to a relative relationship between the preliminary sampling data and the comparison data corresponding to the preset current when the sampling current is in a positive direction, and generate a sampling comparison result according to a relative relationship between the reverse sampling data and the comparison data corresponding to the preset current when the sampling current is in a negative direction.
Specifically, the preliminary processing unit 601 is a processing circuit that performs a preliminary operational amplifier on a sampling current in the sampling circuit 500, and the preliminary processing unit 601 may obtain the sampling current flowing through the sampling resistor R0 and perform the preliminary operational amplifier. The preliminary processing unit 601 may amplify the sampling current by using an operational amplifying circuit, a transistor or other electric signal amplifying circuits, so that the processed preliminary sampling data is larger positive value data more convenient for subsequent processing. Fig. 7 is a schematic diagram of another sampling circuit and a control circuit corresponding to the sampling circuit according to an embodiment of the present invention, and referring to fig. 6 and 7, an exemplary preliminary processing unit 601 may include an operational amplifier 701, a first input terminal a of the operational amplifier 701 is connected to one end of a sampling resistor R0 far from a ground GND, a second input terminal b of the operational amplifier 701 is connected to one end of the sampling resistor R0 near the ground GND, and the first input terminal a is also connected to a reference potential V ref. The output terminal c of the operational amplifier 701 is respectively connected to the direction determining unit 602, the inverse processing unit 603 and the data comparing unit 604, and the operational amplifier 701 is configured to amplify the sampling current according to the reference potential V ref, the sampling current and the resistance value of the sampling resistor R0, and determine preliminary sampling data of the sampling current. The operational amplifier 701 may amplify the sampled current according to a first operational formula, where the first operational formula is OUT 1=GAIN*I*R+Vref, OUT 1 is preliminary sampled data of the sampled current, GAIN is an amplification factor of the operational amplifier 701, and the amplification factor of the operational amplifier 701 may be determined according to an order of magnitude of the sampled current and an order of magnitude to which the sampling circuit 500 is applicable. I is sampling current flowing through a sampling resistor R0, R is the resistance value of the sampling resistor R0, V ref is a reference potential, and the reference potential can be larger than the voltage at two ends when the sampling resistor R0 flows through a preset current peak value, so that sampling data obtained after the sampling current is processed preliminarily is positive.
The direction judging unit 602 is a direction judging circuit of the sampling current, and can compare the preliminary sampling data with the reference potential, and determine the direction of the sampling current according to the relative relationship between the preliminary sampling data and the reference potential. The direction determination unit 602 may perform direction determination of the sampling current using a comparator. Referring to fig. 6 and 7, exemplarily, the direction determining unit 602 may include a first comparator 702, a first input h of the first comparator 702 is connected to the preliminary processing unit 601, and a second input g of the first comparator 702 is connected to the reference potential V ref; the output end of the first comparator 702 is connected with the data comparison unit 604; the first comparator 702 is configured to compare the preliminary sampled data with the reference potential V ref, and determine a direction of the sampling current according to the comparison result. The reference potential V ref is equal to the reference potential to which the operational amplifier is connected, for example, the first comparator 702 may determine that the sampling current direction is forward in case that the preliminary sampling data is greater than the reference potential V ref, thereby outputting a low potential, and the first comparator 702 may also determine that the sampling current direction is reverse in case that the preliminary sampling data is less than the reference potential V ref, thereby outputting a high potential.
The inverse processing unit 603 refers to a data processing circuit capable of performing inverse processing on the preliminary sampling data, where the inverse direction in the inverse processing refers to the direction of the sampling current, and the preliminary sampling data corresponding to the original sampling current may be processed into inverse sampling data, where the inverse sampling data is preliminary sampling data corresponding to the inverse sampling current output by the preliminary processing unit 601 when the inverse sampling current is connected, and the inverse sampling current is a current with a direction opposite to the sampling current and a magnitude identical to the sampling current. Referring to fig. 6 and 7, illustratively, the inverse processing unit 603 may include a subtractor 703, where a first input e of the subtractor 703 is connected to the preliminary processing unit 601, a second input d of the subtractor 703 is connected to a reference potential V ref, an output of the subtractor 703 is connected to a data comparing unit 604, and the subtractor 703 is configured to perform subtraction on the preliminary sample data according to the preliminary sample data and the reference potential V ref, to determine inverse sample data of the sample current. The subtractor 703 may perform a subtraction operation according to a second operation formula, where the second operation formula is OUT 3=2Vref-OUT1, OUT 3 is the inverse sample data of the sample current, V ref is the reference potential, and OUT 1 is the preliminary sample data of the sample current. Since the first operation formula is OUT 1=GAIN*I*R+Vref, OUT 3=2Vref-OUT1=2Vref-(GAIN*I*R+Vref)=-GAIN*I*R+ Vref is obtained, and the backward sampled data OUT 3 is equal to the preliminary sampled data that is determined according to the backward sampled current-I.
The data comparing unit 604 refers to a comparing circuit for comparing the preset current with the sampling current, and can determine the current relative relationship between the sampling current and the preset current. The control end of the data comparison unit 604 is connected with the direction judgment unit 602, the first access end is connected with the preliminary processing unit 601, the second access end is connected with the reverse processing unit 603, the data comparison unit 604 can switch whether the sampling data participating in comparison is preliminary sampling data or reverse sampling data according to the direction of the sampling current accessed by the control end, and further the sampling data participating in comparison is compared with the comparison data corresponding to the preset current, so that the magnitude relation between the current flowing through the coil and the set current is determined, and further the sampling comparison result is generated. The sampling comparison result is a result indicating the trend of the current in the corresponding coil of the sampling resistor R0. If the sampling comparison result shows that the current in the coil is smaller than the preset level, the follow-up circuit can control the current of the coil to rise, and conversely, if the sampling comparison result shows that the current in the coil is larger than the preset level, the follow-up circuit can control the current of the coil to fall, so that accurate control of the stepping motor is realized. Referring to fig. 6 and 7, the data comparing unit 604 includes a multiplexing switch 704 and a second comparator 705, where the multiplexing switch 704 includes a first access terminal j, a second access terminal k, a control terminal m, and a selection result output terminal l; the first access terminal j is connected with the preliminary processing unit 601, the second access terminal k is connected with the reverse processing unit 603, the control terminal m is connected with the direction judging unit 602, and the multi-path selection switch 704 is used for switching the access terminal connected with the selection result output terminal l according to the direction of the sampling current accessed by the control terminal m. The first input end p of the second comparator 705 is connected with the selection result output end l, the second input end n of the second comparator 705 is connected with comparison data corresponding to preset current, the second comparator 705 is used for comparing the comparison data corresponding to the preset current with the data connected with the selection result output end l, a sampling comparison result is determined according to the comparison result, and the sampling comparison result is output to the total control unit through the total output end o. For example, in the case that the comparison result is that the comparison data is larger than the data accessed by the output end of the selection result, the sampling comparison result may be at a high level to indicate that the current of the control coil of the subsequent circuit is increased; in the case that the comparison result is that the comparison data is smaller than the data accessed by the output end of the selection result, the sampling comparison result can be at a low level so as to indicate the subsequent circuit to control the coil current to be reduced.
For example, when the reference potential V ref =2.5v, the resistance value r=0.2Ω of the sampling resistor R0, the operational amplifier ratio gain=20, and the sampling current i=0.2a are set, the preliminary processing unit 601 outputs the preliminary sampling data OUT 1 =20×0.2×0.2+2.5=3.3V in the fast-decay mode, and the inverse processing unit 603 corresponds to the output inverse sampling data OUT 3 =2×2.5-3.3=1.7V. In the driving mode of the stepper motor, the preliminary sampling data OUT 1 =20 (-0.2) 0.2+2.5=1.7v output by the preliminary processing unit 601, and the reverse processing unit 603 corresponds to the reverse sampling data OUT 3 =2×2.5-1.7=3.3v output by the reverse processing unit 603. In the driving mode, the current forms positive voltage at two ends of the sampling resistor R0, the preliminary sampling data OUT 1 is larger than the reference potential V ref, and the output data of the direction judging unit 602 is at low level, so that the selection result output end of the multi-path selection switch 704 is connected with the first access end. In the fast-decay mode, the current forms a negative pressure at two ends of the sampling resistor R0, the preliminary sampling data OUT 1 is smaller than the reference potential V ref, and the output data of the direction judging unit 602 is at a high level, so that the selection result output end of the multi-path selection switch 704 is connected with the second access end. Thus, as long as the current value flowing through the sampling resistor R0 is the same, no matter whether the current direction flowing through the sampling resistor R0 is positive or negative, the selection result output terminal l of the multiplexing switch 704 outputs 3.3V to the second comparator 705, and thus the correct control of the current waveform can be achieved.
The sampling circuit provided in this embodiment includes a preliminary processing unit, a direction judging unit, a reverse processing unit, and a data comparing unit. The primary processing unit is connected with two ends of the sampling resistor and is used for acquiring sampling current and carrying out primary operational amplification processing on the sampling current to generate primary sampling data. The reverse processing unit is connected with the preliminary processing unit and is used for determining reverse sampling data of the sampling current according to the preliminary sampling data. The direction judging unit is connected with the preliminary processing unit and is used for determining the direction of the sampling current according to the preliminary sampling data. The data comparison unit is respectively connected with the preliminary processing unit, the reverse processing unit and the direction judging unit, and is used for generating a sampling comparison result according to the relative relation between the preliminary sampling data and the comparison data corresponding to the preset current under the condition that the sampling current is in the positive direction, and generating the sampling comparison result according to the relative relation between the reverse sampling data and the comparison data corresponding to the preset current under the condition that the sampling current is in the negative direction, thereby realizing accurate sampling and data processing of the current of the stepping motor coil,
The embodiment of the present invention further provides a control device for a stepper motor, and on the basis of the foregoing embodiment, with continued reference to fig. 5, a control device 700 for a stepper motor includes the control circuit 100 and any of the foregoing sampling circuits 500. The master control unit 104 in the control circuit 100 is connected to the sampling circuit 500, and the master control unit 104 is configured to control the working states of the transistors in the upper bridge arm and the lower bridge arm according to the sampling comparison result provided by the sampling circuit 500.
The embodiment of the present invention further provides a stepper motor system, fig. 8 is a schematic diagram of the composition of the stepper motor system provided in the embodiment of the present invention, and referring to fig. 8, the stepper motor system 800 includes the control device 700 and the stepper motor 801 of any of the foregoing stepper motors.
The above embodiments do not limit the scope of the present invention. It will be apparent to those skilled in the art that various modifications, combinations, sub-combinations and alternatives are possible, depending on design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of the present invention.

Claims (9)

1. A sampling circuit, comprising: the sampling resistor and the sampling processing module are used for sampling the sampling signals;
The sampling resistor is arranged between a lower bridge arm connecting point and a grounding end of a control circuit of the stepping motor, wherein the lower bridge arm connecting point is a connecting point between two switching devices in a lower bridge arm;
The sampling processing module is respectively connected with two ends of the sampling resistor, and is used for determining a sampling comparison result according to the sampling current and a preset current when the sampling current flowing through the sampling resistor is in a positive direction, and determining the sampling comparison result according to the reverse processing data of the sampling current and the preset current when the sampling current flowing through the sampling resistor is in a negative direction; the reverse processing data is data obtained after the sampling current is subjected to reverse processing;
the sampling processing module specifically comprises a preliminary processing unit, a direction judging unit, a reverse processing unit and a data comparing unit;
The primary processing unit is connected with two ends of the sampling resistor and is used for acquiring the sampling current and carrying out primary operational amplification on the sampling current to generate primary sampling data;
The reverse processing unit is connected with the preliminary processing unit and is used for determining reverse sampling data of the sampling current according to the preliminary sampling data;
the direction judging unit is connected with the preliminary processing unit and is used for determining the direction of the sampling current according to the preliminary sampling data;
the data comparison unit is respectively connected with the preliminary processing unit, the reverse processing unit and the direction judging unit, and is used for generating the sampling comparison result according to the relative relation between the preliminary sampling data and the comparison data corresponding to the preset current when the sampling current is in the positive direction, and generating the sampling comparison result according to the relative relation between the reverse sampling data and the comparison data corresponding to the preset current when the sampling current is in the negative direction.
2. The sampling circuit according to claim 1, wherein the preliminary processing unit includes an operational amplifier, a first input terminal of the operational amplifier is connected to an end of the sampling resistor far from a ground terminal, a second input terminal of the operational amplifier is connected to an end of the sampling resistor near the ground terminal, and the second input terminal is further connected to a reference potential; the output end of the operational amplifier is respectively connected with the direction judging unit, the reverse processing unit and the data comparing unit, and the operational amplifier is used for amplifying the sampling current according to the reference potential, the sampling current and the resistance value of the sampling resistor to determine the preliminary sampling data of the sampling current.
3. The sampling circuit according to claim 2, wherein the operational amplifier performs the amplifying operation according to a first operational formula, the first operational formula being OUT 1=GAIN*I*R + Vref, wherein OUT 1 is the preliminary sampling data of the sampling current, GAIN is an amplification factor of the operational amplifier, I is the sampling current flowing through the sampling resistor, R is a resistance value of the sampling resistor, and V ref is a reference potential.
4. The sampling circuit according to claim 1, wherein the direction judging unit comprises a first comparator, a first input end of the first comparator is connected with the preliminary processing unit, and a second input end of the first comparator is connected with a reference potential; the output end of the first comparator is connected with the data comparison unit; the first comparator is used for comparing the preliminary sampling data with the reference potential, and determining the direction of the sampling current according to a comparison result.
5. The sampling circuit according to claim 1, wherein the inverse processing unit comprises a subtractor, a first input terminal of the subtractor is connected to the preliminary processing unit, a second input terminal of the subtractor is connected to a reference potential, an output terminal of the subtractor is connected to the data comparing unit, and the subtractor is configured to perform subtraction operation on the preliminary sampling data according to the preliminary sampling data and the reference potential, so as to determine the inverse sampling data of the sampling current.
6. The sampling circuit of claim 5, wherein the subtractor performs the subtraction according to a second operation formula, the second operation formula being OUT 3=2Vref-OUT1, wherein OUT 3 is the inverted sample data of the sample current, V ref is a reference potential, and OUT 1 is the preliminary sample data of the sample current.
7. The sampling circuit of claim 1, wherein the data comparison unit comprises a multiplexing switch and a second comparator;
The multi-path selection switch comprises a first access end, a second access end, a control end and a selection result output end; the first access end is connected with the preliminary processing unit, the second access end is connected with the reverse processing unit, the control end is connected with the direction judging unit, and the multi-path selection switch is used for switching the access end connected with the selection result output end according to the direction of the sampling current accessed by the control end;
The first input end of the second comparator is connected with the selection result output end, the second input end of the second comparator is connected with comparison data corresponding to the preset current, the second comparator is used for comparing the comparison data corresponding to the preset current with the data connected with the selection result output end, and the sampling comparison result is determined according to the comparison result.
8. A stepping motor control apparatus comprising: a control circuit and the sampling circuit of any one of claims 1-7;
and a master control unit in the control circuit is connected with the sampling circuit and is used for controlling the working states of transistors in the upper bridge arm and the lower bridge arm according to the sampling comparison result provided by the sampling circuit.
9. A stepper motor system, the stepper motor system comprising: the stepping motor control device and the stepping motor according to claim 8.
CN202410558905.4A 2024-05-08 2024-05-08 Sampling circuit, control device and stepping motor system Active CN118130888B (en)

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CN111987692A (en) * 2020-07-28 2020-11-24 杭州士兰微电子股份有限公司 Leakage protection circuit, control method thereof and drive circuit
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CN116845819A (en) * 2023-06-15 2023-10-03 上海艾为电子技术股份有限公司 Overcurrent protection circuit, chip and electronic equipment

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Publication number Priority date Publication date Assignee Title
CN103913629A (en) * 2014-03-31 2014-07-09 广东威灵电机制造有限公司 Device for detecting direct current busbar current and control system of motor with the same
CN107947117A (en) * 2017-10-23 2018-04-20 歌尔股份有限公司 A kind of protection circuit of direct current generator
CN109038476A (en) * 2018-08-08 2018-12-18 杭州先途电子有限公司 A kind of current foldback circuit and controller
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