CN111175564A - Three-phase current detection circuit of brushless direct current motor driver - Google Patents
Three-phase current detection circuit of brushless direct current motor driver Download PDFInfo
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- CN111175564A CN111175564A CN202010125882.XA CN202010125882A CN111175564A CN 111175564 A CN111175564 A CN 111175564A CN 202010125882 A CN202010125882 A CN 202010125882A CN 111175564 A CN111175564 A CN 111175564A
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- 238000005070 sampling Methods 0.000 claims abstract description 25
- 239000003990 capacitor Substances 0.000 claims description 12
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- 238000005516 engineering process Methods 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 238000010923 batch production Methods 0.000 description 1
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- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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Abstract
The invention relates to a three-phase current sampling circuit of a brushless direct current motor driver, which is used for acquiring the current values of three phases of an inverter circuit of the brushless direct current motor driver, wherein the three-phase current sampling circuit of the brushless direct current motor driver comprises three current sampling branches, and each current sampling branch is used for acquiring the current value of one phase of the inverter circuit; the current sampling branch includes: the signal acquisition unit is connected with one phase of the inverter circuit and is used for acquiring a current value of one phase of the inverter circuit and converting the current value into a voltage signal; and the signal processing unit is connected with the signal acquisition unit and used for rectifying the voltage signal into a positive voltage signal. According to the invention, each of the inversion units of the brushless direct current motor driver is connected with one signal acquisition unit, so that three-phase current signals can be acquired simultaneously, and the accuracy of three-phase current acquisition can be improved. The invention can realize the function of collecting three-phase current by adopting a simple structure, and can save the collection cost.
Description
Technical Field
The invention relates to the technical field of electronics, in particular to a three-phase current detection circuit of a brushless direct current motor driver.
Background
The brushless direct current motor is composed of a motor main body and a driver, and is a typical electromechanical integration product. The driver is composed of power electronics, integrated circuits, etc., and functions are: receiving starting, stopping and braking signals of the motor to control the starting, stopping and braking of the motor; receiving a position sensor signal and a positive and negative rotation signal, and controlling the on-off of each power tube of the inverter bridge to generate continuous torque; receiving a speed instruction and a speed feedback signal for controlling and adjusting the rotating speed; provide protection and display, etc. Brushless motors are closely linked to the development of electronics, microelectronics, digital technology, automotive technology, and materials science. The device is not only limited to the field of alternating current and direct current, but also relates to the fields of energy conversion, signal sensing and the like of electromotion and power generation. There is a protection measure for the driver, which can cause a large current to burn out the power transistor when the load is too large or the driver is not properly used. In order to protect against damage to the driver due to current exceeding specifications, it is common to sense the current in the inverter circuit of the driver and feed this current back to the DSP for real-time monitoring of the current. In the existing brushless direct current motor driver product, a Hall element is usually adopted to match with some peripheral circuits to detect current, although the technical means is mature and common, the higher price of the technical means increases the great cost for the driver, particularly the great cost burden is caused for the batch production of enterprises, and a plurality of driver enterprises are forbidden. In order to replace a hall element, some engineers short-circuit three branches of a lower bridge arm of an inverter unit, then ground the three branches through a milliohm resistor, and further detect current on the milliohm resistor. Therefore, the existing three-phase current detection circuit for the brushless direct current motor driver has high cost and low accuracy of current detection.
Disclosure of Invention
The invention aims to provide a three-phase current detection circuit of a brushless direct current motor driver, which is used for improving the efficiency of collecting the current of countless direct current motor drivers and saving the collection cost.
In order to achieve the purpose, the invention provides the following scheme:
a three-phase current sampling circuit of a brushless direct current motor driver is used for collecting the current values of three phases of an inverter circuit of the brushless direct current motor driver, and comprises three current sampling branches, wherein each current sampling branch is used for collecting the current value of one phase of the inverter circuit;
the current sampling branch comprises:
the signal acquisition unit is connected with one phase of the inverter circuit and is used for acquiring a current value of one phase of the inverter circuit and converting the current value into a voltage signal;
and the signal processing unit is connected with the signal acquisition unit and used for rectifying the voltage signal into a positive voltage signal.
Optionally, one end of the signal acquisition unit is connected to a lower bridge arm of the inverter circuit, and the other end of the signal acquisition unit is connected to a ground wire.
Optionally, the signal acquisition unit is a resistor.
Optionally, the resistance of the resistor is 5m Ω.
Optionally, the signal processing unit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, an operational amplifier, and a clamp circuit;
one end of the first resistor is connected to a connection point of the signal acquisition unit and the lower bridge arm, and the other end of the first resistor is connected with the positive input end of the operational amplifier;
one end of the second resistor is connected to a connection point of the signal acquisition unit and the ground wire, and the other end of the first resistor is connected with the reverse input end of the operational amplifier;
one end of the third resistor is connected with the output end of the operational amplifier, the other end of the third resistor is connected with one end of the fourth resistor, and the other end of the fourth resistor is connected with the clamping circuit;
one end of the fifth resistor is connected with the inverting input end of the operational amplifier, and the other end of the fifth resistor is connected to the connection point of the third resistor and the fourth resistor.
Optionally, the signal processing unit further includes a filter circuit, where the filter circuit includes a sixth resistor, a first capacitor, and a reference voltage generation module;
one end of the sixth resistor is connected with the reference voltage generation module, the other end of the sixth resistor is connected with one end of the first capacitor, and the other end of the first capacitor is grounded;
and the connection point of the sixth resistor and the first capacitor is connected to the connection point of the first resistor and the positive input end.
Optionally, the reference voltage generating module includes a power chip and a voltage follower;
the power supply chip is respectively connected with an external power supply and the voltage follower, the power supply chip is used for converting an external power supply signal into a stable reference voltage signal, and the voltage follower is used for transmitting the reference voltage signal.
Optionally, the clamping circuit comprises a first diode and a second diode;
the anode of the first diode is grounded, the cathode of the first diode is connected with the anode of the second diode, and the anode of the second diode is connected with the voltage-limiting power supply.
Optionally, the voltage-limited power supply has a voltage value of 3.3V.
Optionally, the voltage value of the external power supply is 5V.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects:
according to the invention, each of the inversion units of the brushless direct current motor driver is connected with one signal acquisition unit, so that three-phase current signals can be acquired simultaneously, and the accuracy of three-phase current acquisition can be improved. The invention can realize the function of collecting three-phase current by adopting a simple structure, and can save the collection cost.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments 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 without inventive exercise.
Fig. 1 is a schematic structural diagram of a three-phase current detection circuit of a brushless dc motor driver according to the present invention;
FIG. 2 is a schematic circuit diagram of a three-phase current detection circuit signal processing unit of the brushless DC motor driver according to the present invention;
fig. 3 is a schematic circuit diagram of a reference voltage generating module of a three-phase current detection circuit of a brushless dc motor driver according to the present invention.
Description of the symbols:
a signal acquisition unit-1; a signal processing unit-2; DSP processor-3.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention aims to provide a three-phase current detection circuit of a brushless direct current motor driver, which is used for improving the efficiency of collecting the current of countless direct current motor drivers and saving the collection cost.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
Fig. 1 is a schematic structural diagram of a three-phase current detection circuit of a brushless dc motor driver according to the present invention, and as shown in fig. 1, the three-phase current detection circuit of the brushless dc motor driver according to the present invention includes three current sampling branches, each of which is used for collecting a current value of one phase of the inverter circuit.
Each current sampling branch comprises a signal acquisition unit 1 and a signal processing unit 2.
The signal acquisition unit 1 is connected with one of the inverter circuits. One end of the signal acquisition unit 1 is connected with a lower bridge arm of the inverter circuit, and the other end of the signal acquisition unit 1 is connected with a ground wire.
The signal acquisition unit 1 is used for acquiring a current value of one phase of the inverter circuit and converting the current value into a voltage signal.
In this embodiment, the signal acquisition unit 1 is a resistor. One end of the resistor is connected with a lower bridge arm of the inverter circuit, and the other end of the resistor is connected with a ground wire.
The resistance value of the resistor is 5m omega. But is not limited thereto and can be selected by those skilled in the art according to actual needs. The smaller the resistance value of the resistor is, the higher the accuracy of the acquired current value is.
The signal processing unit 2 is connected with the signal acquisition unit 1, and the signal acquisition unit 1 is used for rectifying the voltage signal into a positive voltage signal and transmitting the positive voltage signal to the DSP processor.
The DSP processor informs monitoring of the positive voltage signals output by the 3 signal processing units 2.
As shown in fig. 2, the signal acquisition unit 1 specifically includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, an operational amplifier, and a clamp circuit.
The clamping circuit includes a first diode and a second diode.
The anode of the first diode is grounded, the cathode of the first diode is connected with the anode of the second diode, and the anode of the second diode is connected with the voltage-limiting power supply.
The voltage limited power supply is preferably 3.3V.
The clamping circuit can ensure that a positive voltage signal output by the signal processing unit 2 is always kept at 0-3.3V, and the DSP processor is prevented from being burnt due to overhigh output voltage.
One end of the first resistor is connected to a connection point of the signal acquisition unit 1 (i.e., a resistor) and the lower bridge arm, and the other end of the first resistor is connected to a positive input end of the operational amplifier.
One end of the second resistor is connected to a connection point of the signal acquisition unit 1 and a ground wire, and the other end of the first resistor is connected to the reverse input end of the operational amplifier.
One end of the third resistor is connected with the output end of the operational amplifier, the other end of the third resistor is connected with one end of the fourth resistor, and the other end of the fourth resistor is connected with the clamping circuit.
One end of the fifth resistor is connected with the inverting input end of the operational amplifier, and the other end of the fifth resistor is connected to the connection point of the third resistor and the fourth resistor.
The signal processing unit 2 further comprises a filter circuit for improving the accuracy of the signal.
The filter circuit specifically comprises a sixth resistor, a first capacitor and a reference voltage generation module.
One end of the sixth resistor is connected with the reference voltage generation module, the other end of the sixth resistor is connected with one end of the first capacitor, and the other end of the first capacitor is grounded.
And the connection point of the sixth resistor and the first capacitor is connected to the connection point of the first resistor and the positive input end.
As shown in fig. 3, the reference voltage generating module includes a power chip and a voltage follower.
The power supply chip is respectively connected with an external power supply and the voltage follower, the power supply chip is used for converting an external power supply signal into a stable reference voltage signal, and the voltage follower is used for transmitting the reference voltage signal.
In this embodiment, the external power source is + 5V. And the +5V external power supply voltage is converted into 1.8V and then output to the voltage follower after passing through the power supply chip. The voltage follower can isolate the influence of the front-end circuit on the output end, so that the output voltage can be stabilized at 1.8V.
The voltage values described in this embodiment are only one preferable mode, and those skilled in the art can select appropriate voltage values as needed.
The invention further discloses the following technical effects:
1. the resistance of milliohm level is selected to collect the current value of the inverter circuit, so that the collection precision is improved.
2. The components used in the invention are common components, so that the use cost can be reduced.
3. The circuit is simple in structure and easy to build, the error rate of the built circuit can be reduced, and the acquisition efficiency is further improved.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.
Claims (10)
1. A three-phase current sampling circuit of a brushless direct current motor driver is used for collecting the current values of three phases of an inverter circuit of the brushless direct current motor driver, and is characterized in that the three-phase current sampling circuit of the brushless direct current motor driver comprises three current sampling branches, and each current sampling branch is used for collecting the current value of one phase of the inverter circuit;
the current sampling branch comprises:
the signal acquisition unit is connected with one phase of the inverter circuit and is used for acquiring a current value of one phase of the inverter circuit and converting the current value into a voltage signal;
and the signal processing unit is connected with the signal acquisition unit and used for rectifying the voltage signal into a positive voltage signal.
2. The three-phase current sampling circuit of the brushless direct current motor driver according to claim 1, wherein one end of the signal acquisition unit is connected to a lower bridge arm of the inverter circuit, and the other end of the signal acquisition unit is connected to a ground wire.
3. The three-phase current sampling circuit of claim 2, wherein the signal acquisition unit is a resistor.
4. The three-phase current sampling circuit of the brushless dc motor driver of claim 3, wherein the resistance of the resistor is 5m Ω.
5. The three-phase current sampling circuit of the brushless direct current motor driver according to claim 2, wherein the signal processing unit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, an operational amplifier and a clamping circuit;
one end of the first resistor is connected to a connection point of the signal acquisition unit and the lower bridge arm, and the other end of the first resistor is connected with the positive input end of the operational amplifier;
one end of the second resistor is connected to a connection point of the signal acquisition unit and the ground wire, and the other end of the first resistor is connected with the reverse input end of the operational amplifier;
one end of the third resistor is connected with the output end of the operational amplifier, the other end of the third resistor is connected with one end of the fourth resistor, and the other end of the fourth resistor is connected with the clamping circuit;
one end of the fifth resistor is connected with the inverting input end of the operational amplifier, and the other end of the fifth resistor is connected to the connection point of the third resistor and the fourth resistor.
6. The three-phase current sampling circuit of the brushless direct current motor driver according to claim 5, wherein the signal processing unit further comprises a filter circuit, the filter circuit comprises a sixth resistor, a first capacitor and a reference voltage generating module;
one end of the sixth resistor is connected with the reference voltage generation module, the other end of the sixth resistor is connected with one end of the first capacitor, and the other end of the first capacitor is grounded;
and the connection point of the sixth resistor and the first capacitor is connected to the connection point of the first resistor and the positive input end.
7. The three-phase current sampling circuit of the brushless dc motor driver of claim 6, wherein the reference voltage generating module comprises a power chip and a voltage follower;
the power supply chip is respectively connected with an external power supply and the voltage follower, the power supply chip is used for converting an external power supply signal into a stable reference voltage signal, and the voltage follower is used for transmitting the reference voltage signal.
8. The brushless dc motor driver three-phase current sampling circuit cross-reference of claim 5, wherein the clamp circuit comprises a first diode and a second diode;
the anode of the first diode is grounded, the cathode of the first diode is connected with the anode of the second diode, and the anode of the second diode is connected with the voltage-limiting power supply.
9. The three-phase current sampling circuit of the brushless dc motor driver of claim 8, wherein the voltage value of the voltage limited power supply is 3.3V.
10. The three-phase current sampling circuit of claim 7, wherein the voltage value of the external power source is 5V.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010125882.XA CN111175564A (en) | 2020-02-27 | 2020-02-27 | Three-phase current detection circuit of brushless direct current motor driver |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010125882.XA CN111175564A (en) | 2020-02-27 | 2020-02-27 | Three-phase current detection circuit of brushless direct current motor driver |
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| CN111175564A true CN111175564A (en) | 2020-05-19 |
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| CN202010125882.XA Pending CN111175564A (en) | 2020-02-27 | 2020-02-27 | Three-phase current detection circuit of brushless direct current motor driver |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111697879A (en) * | 2020-06-30 | 2020-09-22 | 深圳和而泰智能控制股份有限公司 | Motor starting control system and motor control method |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20120119687A1 (en) * | 2010-11-17 | 2012-05-17 | Kabushiki Kaisha Toshiba | Brushless motor driver and brushless motor system |
| CN102545161A (en) * | 2012-02-09 | 2012-07-04 | 西安理工大学 | Overcurrent protection device of variable-frequence governor |
| CN102981042A (en) * | 2012-12-07 | 2013-03-20 | 深圳市安邦信电子有限公司 | Three-phase current detection circuit for frequency converter |
| CN207866881U (en) * | 2018-01-19 | 2018-09-14 | 苏州大学 | The phase current sensing of permanent magnet synchronous motor protects circuit |
| CN109510172A (en) * | 2018-11-27 | 2019-03-22 | 珂伯特机器人（天津）有限公司 | A kind of the control system for non-brush direct currunt electromotors of coaxial two wheels robot |
-
2020
- 2020-02-27 CN CN202010125882.XA patent/CN111175564A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20120119687A1 (en) * | 2010-11-17 | 2012-05-17 | Kabushiki Kaisha Toshiba | Brushless motor driver and brushless motor system |
| CN102545161A (en) * | 2012-02-09 | 2012-07-04 | 西安理工大学 | Overcurrent protection device of variable-frequence governor |
| CN102981042A (en) * | 2012-12-07 | 2013-03-20 | 深圳市安邦信电子有限公司 | Three-phase current detection circuit for frequency converter |
| CN207866881U (en) * | 2018-01-19 | 2018-09-14 | 苏州大学 | The phase current sensing of permanent magnet synchronous motor protects circuit |
| CN109510172A (en) * | 2018-11-27 | 2019-03-22 | 珂伯特机器人（天津）有限公司 | A kind of the control system for non-brush direct currunt electromotors of coaxial two wheels robot |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111697879A (en) * | 2020-06-30 | 2020-09-22 | 深圳和而泰智能控制股份有限公司 | Motor starting control system and motor control method |
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Application publication date: 20200519 |
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