CN209513895U - A kind of current sampling circuit for motor control - Google Patents
A kind of current sampling circuit for motor control Download PDFInfo
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- CN209513895U CN209513895U CN201822271983.9U CN201822271983U CN209513895U CN 209513895 U CN209513895 U CN 209513895U CN 201822271983 U CN201822271983 U CN 201822271983U CN 209513895 U CN209513895 U CN 209513895U
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Abstract
The utility model discloses a kind of current sampling circuits for motor control, including biasing circuit, first resistor, second resistance, 3rd resistor, 4th resistance and the first operational amplifier, the first resistor is connected with by sample motor, the first end of the first resistor is connected with the first end of second resistance, the second end of the first resistor and the first end of 3rd resistor are grounded, the second end of the second resistance and the output end of biasing circuit are connect with the normal phase input end of the first operational amplifier, the second end of the 3rd resistor is connect with the inverting input terminal of the first operational amplifier with the first end of the 4th resistance, the second end of 4th resistance is connect with the output end of the first operational amplifier.The utility model design is simple, and used component price is low, greatly reduces the design cost of the utility model.The utility model can be widely applied to electronic technology field.
Description
Technical field
The utility model relates to electronic technology field, especially a kind of current sampling circuit for motor control.
Background technique
In electric machines control technology, for the purpose of safety, need to realize closed-loop control.Especially some household products,
Such as children's same table, to the more demanding of safety.By taking children's same table as an example, Yao Shixian closed-loop control needs to detect motor
Working condition and operating current.But if realizing closed-loop control using the scheme of sensor, higher cost can be generated,
For the not high household products of value of the product, it will increase many costs.Especially if also needing to add other sensors
Come when sampling the reliability of such as temperature data to guarantee motor, cost can be further increased.
Utility model content
In order to solve the above technical problems, the purpose of this utility model is that: it provides a kind of at low cost for motor control
Current sampling circuit.
Technical solution adopted in the utility model is:
A kind of current sampling circuit for motor control, including biasing circuit, first resistor, second resistance, third electricity
Resistance, the 4th resistance and the first operational amplifier, the first resistor are connected with by sample motor, the first end of the first resistor
It being connected with the first end of second resistance, the second end of the first resistor and the first end of 3rd resistor are grounded, and described second
The second end of resistance and the output end of biasing circuit are connect with the normal phase input end of the first operational amplifier, the 3rd resistor
Second end connect with the inverting input terminal of the first operational amplifier with the first end of the 4th resistance, the of the 4th resistance
Two ends are connect with the output end of the first operational amplifier.
It further, further include first capacitor and the second capacitor, the first capacitor is being connected to the first operational amplifier just
Between phase input terminal and ground, second capacitor and the 4th resistor coupled in parallel.
Further, the biasing circuit is first voltage follower.
Further, the first voltage follower includes second operational amplifier, the 7th resistance and the 8th resistance, and described
The output end of two operational amplifiers is connect with the normal phase input end of the inverting input terminal of itself and the first operational amplifier respectively,
The first end of 7th resistance and the first end of the 8th resistance are connect with the normal phase input end of second operational amplifier, described
The second end of 7th resistance is connect with positive pole, the second end of the 8th resistance and the power cathode of second operational amplifier
Input terminal connection.
Further, the first voltage follower further includes third capacitor, the 4th capacitor and the 5th capacitor, the third electricity
Appearance is connected between the output end of second operational amplifier and the second end of the 8th resistance, and the 4th capacitor and the 8th resistance are simultaneously
Connection, the 5th capacitance connection is between the second end of the 7th resistance and the second end of the 8th resistance.
It further, further include second voltage follower, the output of the second voltage follower and the first operational amplifier
End connection.
Further, the second voltage follower includes the 5th resistance, the 6th resistance, the 6th capacitor, the 7th capacitor and the
The first end of three operational amplifiers, the 5th resistance is connect with the output end of the first operational amplifier, the 5th resistance
Second end, the first end of the 6th resistance are connect with the first end of the 6th capacitor, the second end of the 6th resistance and the 7th electricity
The first end of appearance is connect with the normal phase input end of third operational amplifier, the second end of the 6th capacitor and the 7th capacitor
Second end is grounded, and the output end of the third operational amplifier is connect with the inverting input terminal of itself.
The beneficial effects of the utility model are: the utility model carries out current sample by first resistor, and load is existed
Voltage in first resistor amplifies, to provide a sampled voltage for processor, the utility model is also additionally arranged biasing
Circuit, so that circuit can measure the negative-phase sequence curent that motor is generated when shutting down using single supply, this is practical new
Type design is simple, and used component price is low, greatly reduces the design cost of the utility model.
Detailed description of the invention
Fig. 1 is a kind of circuit diagram of specific embodiment of the utility model.
Specific embodiment
The utility model is further detailed with specific embodiment with reference to the accompanying drawings of the specification.
Referring to Fig.1, a kind of current sampling circuit for motor control, including biasing circuit, first resistor R1, the second electricity
Resistance R2,3rd resistor R3, the 4th resistance R4 and the first operational amplifier U1, the first resistor R1 connect with by sample motor,
That is first resistor R1, which is crossed at upstream, to be flowed through by the first end of the electric current Io, the first resistor R1 of sample motor and second resistance R2
First end connection, the second end of the first resistor R1 and the first end of 3rd resistor R3 are grounded GND, the second resistance R2
Second end and the output end of biasing circuit connect with the normal phase input end of the first operational amplifier U1, the 3rd resistor R3
Second end connect with the inverting input terminal of the first operational amplifier U1 with the first end of the 4th resistance R4, the 4th resistance
The second end of R4 is connect with the output end of the first operational amplifier U1.
In motor work, according to the difference of its working condition, the electric current for flowing through motor can become 10A from 0, and part is micro-
The voltage that low current generates in first resistor may be smaller, is difficult to be detected in complicated electromagnetic environment, furthermore in motor
When shutdown, since there are coils in electrode, reverse current, the i.e. electric current contrary with electric current Io can be generated.Therefore, at this
Biasing circuit is added in embodiment to provide bias voltage, on the one hand can promote the anti-interference ability of the first operational amplifier,
In order to detect Weak current.Adding biasing circuit simultaneously can make this circuit can be in the case where not using dual power supply
Detect reverse current.
The working principle of the present embodiment are as follows: when electric current Io flows through first resistor R1, electricity can be generated on first resistor R1
Pressure loads normal phase input end and inverting input terminal that the voltage on resistance R1 has respectively entered the first operational amplifier U1,
In, the first operational amplifier U1 can will load first resistor R1 on X times of voltage amplification, wherein X for the 4th resistance R4 resistance value
The ratio between with the resistance value of second resistance R2.In the present embodiment, processor obtains the output voltage of the first operational amplifier U1, passes through
ADC interface is sampled, and realizes closed-loop control after then handling sampled data.
When motor stopping, since there are coils can generate reverse current for motor, at this point, reverse current will lead to the first fortune
It calculates amplifier U1 and exports a voltage value lower than bias voltage provided by biasing circuit.Therefore processor can be according to voltage
The size of value determines whether motor shuts down.
It referring to Fig.1, further include first capacitor C1 and the second capacitor C2, the first capacitor C1 as preferred embodiment
It is connected between the normal phase input end and ground GND of the first operational amplifier U1, the second capacitor C2 is in parallel with the 4th resistance R4.
Interference can be filtered by adding first capacitor C1.Shaping can be played the role of and stablize output signal by adding the second capacitor C2.
As preferred embodiment, the biasing circuit is first voltage follower.It is realized using voltage follower partially
The buffering and isolation of voltage can may be implemented in circuits for the first operational amplifier.
Referring to Fig.1, as preferred embodiment, the first voltage follower includes second operational amplifier U2, the 7th
Resistance R7 and the 8th resistance R8, the output end of the second operational amplifier U2 respectively with the inverting input terminal of itself and first
The normal phase input end of operational amplifier U1 connects, and the first end of the first end of the 7th resistance R7 and the 8th resistance R8 are with the
The normal phase input end of two operational amplifier U2 connects, and the second end of the 7th resistance R7 is connect with positive pole 3.3V, described
The second end of 8th resistance R8 is connect with the power supply negative input terminal of second operational amplifier U2.
In the present embodiment, the resistance value of the 7th resistance R7 and the 8th resistance R8 is identical, therefore the present embodiment is provided
Bias voltage be 1.65V.
Referring to Fig.1, as preferred embodiment, the first voltage follower further includes third capacitor C3, the 4th capacitor
C4 and the 5th capacitor C5, the third capacitor C3 be connected to second operational amplifier U2 output end and the 8th resistance R8 second
Between end, the 4th capacitor C4 is in parallel with the 8th resistance R8, and the 5th capacitor C5 is connected to the second end of the 7th resistance R7
Between the second end of the 8th resistance R8.
It referring to Fig.1, further include second voltage follower as preferred embodiment, the second voltage follower and
The output end of one operational amplifier U1 connects.The present embodiment is additionally arranged second voltage follower, can be the first operational amplifier
U1 provides the output of a low resistance state, reduces motor current signal interference.
Referring to Fig.1, as preferred embodiment, the second voltage follower include the 5th resistance R5, the 6th resistance R6,
6th capacitor C6, the 7th capacitor C7 and third operational amplifier U3, the first end and the first operation amplifier of the 5th resistance R5
The output end of device U1 connects, the second end of the 5th resistance R5, the first end of the 6th resistance R6 with the 6th capacitor C6 the
One end connection, the positive of the second end of the 6th resistance R6 and the first end of the 7th capacitor C7 with third operational amplifier U3
Input terminal connection, the second end of the 6th capacitor C6 and the second end of the 7th capacitor C7 are grounded GND, and the third operation is put
The output end of big device U3 is connect with the inverting input terminal of itself, and the output end of the third operational amplifier U3 is as current sample
The output end OUT of circuit.
It is to be illustrated to the preferable implementation of the utility model, but the utility model is not limited to the reality above
Example is applied, those skilled in the art can also make various equivalent changes without departing from the spirit of the present invention
Shape or replacement, these equivalent deformations or replacement are all included in the scope defined by the claims of the present application.
Claims (7)
1. a kind of current sampling circuit for motor control, it is characterised in that: including biasing circuit, first resistor, the second electricity
Resistance, 3rd resistor, the 4th resistance and the first operational amplifier, the first end of the first resistor and the first end of second resistance connect
It connects, the second end of the first resistor and the first end of 3rd resistor are grounded, the second end and biased electrical of the second resistance
The output end on road is connect with the normal phase input end of the first operational amplifier, the second end of the 3rd resistor and the 4th resistance
First end is connect with the inverting input terminal of the first operational amplifier, the second end and the first operational amplifier of the 4th resistance
Output end connection.
2. a kind of current sampling circuit for motor control according to claim 1, it is characterised in that: further include first
Capacitor and the second capacitor, the first capacitor are connected between the normal phase input end and ground of the first operational amplifier, and described second
Capacitor and the 4th resistor coupled in parallel.
3. a kind of current sampling circuit for motor control according to claim 1, it is characterised in that: the biased electrical
Road is first voltage follower.
4. a kind of current sampling circuit for motor control according to claim 3, it is characterised in that: first electricity
Pressure follower includes second operational amplifier, the 7th resistance and the 8th resistance, the output end difference of the second operational amplifier
It is connect with the inverting input terminal of itself and the normal phase input end of the first operational amplifier, the first end of the 7th resistance and
The first end of eight resistance is connect with the normal phase input end of second operational amplifier, and the second end and power supply of the 7th resistance are just
Pole connection, the second end of the 8th resistance and the power supply negative input terminal of second operational amplifier connect.
5. a kind of current sampling circuit for motor control according to claim 4, it is characterised in that: first electricity
Pressing follower further includes third capacitor, the 4th capacitor and the 5th capacitor, and the third capacitance connection is in second operational amplifier
Between output end and the second end of the 8th resistance, the 4th capacitor and the 8th resistor coupled in parallel, the 5th capacitance connection is
Between the second end of seven resistance and the second end of the 8th resistance.
6. a kind of current sampling circuit for motor control according to claim 1, it is characterised in that: further include second
Voltage follower, the second voltage follower are connect with the output end of the first operational amplifier.
7. a kind of current sampling circuit for motor control according to claim 6, it is characterised in that: second electricity
Pressing follower includes the 5th resistance, the 6th resistance, the 6th capacitor, the 7th capacitor and third operational amplifier, the 5th resistance
First end connect with the output end of the first operational amplifier, second end, the first end of the 6th resistance of the 5th resistance are equal
Connect with the first end of the 6th capacitor, the first end of the second end of the 6th resistance and the 7th capacitor with third operation amplifier
The normal phase input end of device connects, and the second end of the 6th capacitor and the second end of the 7th capacitor are grounded, the third operation
The output end of amplifier is connect with the inverting input terminal of itself.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201822271983.9U CN209513895U (en) | 2018-12-29 | 2018-12-29 | A kind of current sampling circuit for motor control |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201822271983.9U CN209513895U (en) | 2018-12-29 | 2018-12-29 | A kind of current sampling circuit for motor control |
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| Publication Number | Publication Date |
|---|---|
| CN209513895U true CN209513895U (en) | 2019-10-18 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201822271983.9U Active CN209513895U (en) | 2018-12-29 | 2018-12-29 | A kind of current sampling circuit for motor control |
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| CN (1) | CN209513895U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111308178A (en) * | 2020-03-19 | 2020-06-19 | 苏州挚途科技有限公司 | Phase current sampling device |
-
2018
- 2018-12-29 CN CN201822271983.9U patent/CN209513895U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111308178A (en) * | 2020-03-19 | 2020-06-19 | 苏州挚途科技有限公司 | Phase current sampling device |
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