CN104242782A - Control circuit for current control of variable frequency fan - Google Patents
Control circuit for current control of variable frequency fan Download PDFInfo
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- CN104242782A CN104242782A CN201410459073.7A CN201410459073A CN104242782A CN 104242782 A CN104242782 A CN 104242782A CN 201410459073 A CN201410459073 A CN 201410459073A CN 104242782 A CN104242782 A CN 104242782A
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- phase current
- control
- control circuit
- sampling
- current
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Abstract
The invention provides a control circuit for current control of a variable frequency fan. The control circuit comprises a control circuit body for current control. The control circuit body comprises a phase current input end and at least one sampling resistor. The phase current input end is used for receiving phase currents and the sampling resistor is used for sampling the phase currents. The control circuit for current control of the variable frequency fan has the advantages that the sampling precision of the phase currents is improved by increasing the resistance of the sampling resistor, and therefore the control precision of the phase currents is improved.
Description
Technical field
The present invention relates to air conditioner controlling technology, especially relate to the control circuit of frequency conversion fan Current Control.
Background technology
Prior art is for frequency conversion fan Current Control, under the occasion adopting single resistance, the resistance of usual employing 15 milliohm-50 milliohm is as sampling resistor, thus realize sampling to electric machine phase current, then the voltage corresponding to the phase current obtained sampling by amplifying circuits such as operational amplifiers is carried out amplifications and processes.
But, when described amplifying circuit amplifies voltage, also can amplify interference signal, therefore, multiplication factor can not be too large, simultaneously, power of motor again due to frequency conversion fan is lower, electric current is less, causes current resolution lower, finally, cause the very large error of calculation, particularly axis error, makes frequency conversion fan current control accuracy lower, and pole is not easy to control.
Summary of the invention
Technical problem to be solved by this invention is that the control precision of frequency conversion fan Current Control in prior art is lower.
For overcoming the problems referred to above, the invention provides the control circuit of frequency conversion fan Current Control, comprise the control circuit body of Current Control, phase current input and at least one sampling resistor is comprised in described control circuit body, described phase current input is for accessing phase current, and described sampling resistor is used for sampling to phase current, by improving the resistance of sampling resistor, to improve the sampling precision of described phase current, thus improve the control precision of phase current.
Further, described control circuit body also comprises amplifier, and described amplifier is used for the voltage corresponding to described phase current and amplifies, wherein, by improving the multiplication factor of described amplifier, to improve the sampling precision of described phase current, thus improve the control precision of phase current.
The invention has the beneficial effects as follows: in the control circuit of frequency conversion fan Current Control, by improving the resistance of sampling resistor, to improve the sampling precision of phase current, thus achieve the technique effect of the control precision improving phase current, meanwhile, control is also made to become simple.
Accompanying drawing explanation
Fig. 1 is the structural representation of the control circuit of the frequency conversion fan Current Control of the present invention under a kind of embodiment.
Embodiment
Below in conjunction with accompanying drawing, the technical scheme of the application is described in detail.
In this application, the control circuit of frequency conversion fan Current Control comprises: the control circuit body of Current Control, in control circuit body, comprise phase current input and at least one sampling resistor, phase current input is for accessing phase current, and sampling resistor is used for sampling to phase current.Wherein, the quantity of the sampling resistor that different control circuit bodies comprises may be different, concrete, a sampling resistor can be comprised in control circuit body, and utilize this sampling resistor to sample to phase current, in addition, in control circuit body, also two or three sampling resistors can be comprised, and utilizing two or three sampling resistors described to sample to phase current, the application does not limit.
The application, by improving the resistance of sampling resistor, can realize the raising of the sampling precision to phase current, and then can improve the control precision of phase current.Concrete, when phase current is I, and when sampling resistor is R, the voltage V that phase current is corresponding has following relational expression: V=IR, after amplifying F times by amplifier, and the amplification voltage V obtained
1there is following relational expression: V
1=IRF.Usually, the sampling employing conversion accuracy of single-chip microcomputer to phase current is the analog-to-digital conversion of 10, and its transformation result AD is 1023 to the maximum, and transformation result AD has following relational expression:
wherein, V
reffor switching reference voltages, V in transfer process
reffor definite value, be generally 5V.Work as V
refduring for 5V, transformation result AD can be obtained there is following formula: AD=204.6IRF.Visible, by improving the value of sampling resistor R, can improve the value of transformation result AD, the value of AD is larger, then the sampling precision of control circuit body to phase current is larger, and the control precision of phase current is higher.
Further, described control circuit body also comprises amplifier, and described amplifier is used for the voltage corresponding to described phase current and amplifies, wherein, by improving the multiplication factor of described amplifier, to improve the sampling precision of described phase current, thus improve the control precision of phase current.Concrete, by improving multiplication factor F, also can improve the value of transformation result AD, the value of AD is larger, then the sampling precision of control circuit body to phase current is larger, and the control precision of phase current is higher.
The application provides a kind of specific embodiment, as shown in Figure 1, described control circuit body comprises resistance R0-R6, wherein, R0 is sampling resistor, between the IPM that R0 is connected to inner integrated 6 IGBT and source current ground, namely B point connects brachium pontis IGBT emitter under IPM, A point connection DC bus power supply, export and flow back to power supply ground by brachium pontis under IPM, U1 is amplifier, R4 and R5 is divider resistance, and U1 accesses voltage V by resistance R6
0, V
0for reference voltage,
for the multiplication factor of amplifier, i.e. F, the voltage corresponding with phase current is V
dc, V
dcthere is following formula: V
dc=F × (V
0+ IR
0), and transformation result AD has following formula:
Therefore,
Work as V
refduring for 5V, by increasing the resistance of sampling resistor R0, the value of AD increases, and the sampling precision of phase current is improved, thus the control precision of phase current also improves thereupon.In addition, on this basis, also can improve the value of F, namely improve
value, the sampling precision of phase current is improved, thus the control precision of phase current also improves thereupon.
It should be noted that, in different air-conditioning systems, the scope of phase current is different, then the span of corresponding sampling resistor is also different, by the resistance of existing sampling resistor is improved, the sampling precision of phase current can be improved, thus improve the control precision of phase current, such as, the sampling resistor chosen when prior art is 10m Ω, then utilize the technical scheme of the application, improve the resistance of sampling resistor, the resistance of sampling resistor is made to be greater than 10m Ω, then can improve the sampling precision of phase current, in addition, when the sampling resistor that prior art is chosen is 50m Ω, utilize the technical scheme of the application, improve the resistance of sampling resistor, the resistance of sampling resistor is made to be greater than 50m Ω, then can improve the sampling precision of phase current.
In this application, by improving the resistance of sampling resistor, the sampling precision of phase current can be improved, and then the accuracy of checkout result and accuracy can both be improved in the link such as calculating, electric current loop calculating of axis error.
Claims (2)
1. the control circuit of frequency conversion fan Current Control, comprise the control circuit body of Current Control, phase current input and at least one sampling resistor is comprised in described control circuit body, described phase current input is for accessing phase current, described sampling resistor is used for sampling to phase current, it is characterized in that, by improving the resistance of sampling resistor, to improve the sampling precision of described phase current, thus improve the control precision of phase current.
2. the control circuit of frequency conversion fan Current Control as claimed in claim 1, it is characterized in that, described control circuit body also comprises amplifier, described amplifier is used for the voltage corresponding to described phase current and amplifies, wherein, by improving the multiplication factor of described amplifier, to improve the sampling precision of described phase current, thus improve the control precision of phase current.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410459073.7A CN104242782A (en) | 2014-09-11 | 2014-09-11 | Control circuit for current control of variable frequency fan |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410459073.7A CN104242782A (en) | 2014-09-11 | 2014-09-11 | Control circuit for current control of variable frequency fan |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN104242782A true CN104242782A (en) | 2014-12-24 |
Family
ID=52230286
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410459073.7A Pending CN104242782A (en) | 2014-09-11 | 2014-09-11 | Control circuit for current control of variable frequency fan |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104242782A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105548676A (en) * | 2015-12-16 | 2016-05-04 | 四川长虹电器股份有限公司 | Single-resistor current sampling method and air conditioner |
| CN108562788A (en) * | 2018-05-23 | 2018-09-21 | 广东伊莱斯电机有限公司 | A kind of control method improving analog loopback sampling precision |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07225044A (en) * | 1994-02-10 | 1995-08-22 | Fujitsu General Ltd | Operation control device for air conditioner |
| CN2699312Y (en) * | 2004-03-15 | 2005-05-11 | 广州数控设备有限公司 | Electric motor three-phase current detecting circuit for machine tool AC servo system |
| CN201260144Y (en) * | 2008-09-27 | 2009-06-17 | 海信（山东）空调有限公司 | Phase current detection amplifying circuit and air conditioner comprising the circuit |
| CN101552571A (en) * | 2001-09-25 | 2009-10-07 | 大金工业株式会社 | Phase current detector |
| CN201993412U (en) * | 2010-12-30 | 2011-09-28 | 宁波三星电气股份有限公司 | Electric energy meter sampling circuit |
-
2014
- 2014-09-11 CN CN201410459073.7A patent/CN104242782A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07225044A (en) * | 1994-02-10 | 1995-08-22 | Fujitsu General Ltd | Operation control device for air conditioner |
| CN101552571A (en) * | 2001-09-25 | 2009-10-07 | 大金工业株式会社 | Phase current detector |
| CN2699312Y (en) * | 2004-03-15 | 2005-05-11 | 广州数控设备有限公司 | Electric motor three-phase current detecting circuit for machine tool AC servo system |
| CN201260144Y (en) * | 2008-09-27 | 2009-06-17 | 海信（山东）空调有限公司 | Phase current detection amplifying circuit and air conditioner comprising the circuit |
| CN201993412U (en) * | 2010-12-30 | 2011-09-28 | 宁波三星电气股份有限公司 | Electric energy meter sampling circuit |
Non-Patent Citations (1)
| Title |
|---|
| 百度文库: "三相异步电机、电流采样电阻", 《百度文库》 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105548676A (en) * | 2015-12-16 | 2016-05-04 | 四川长虹电器股份有限公司 | Single-resistor current sampling method and air conditioner |
| CN105548676B (en) * | 2015-12-16 | 2019-05-07 | 四川长虹电器股份有限公司 | A kind of list resistor current method of sampling and air-conditioning equipment |
| CN108562788A (en) * | 2018-05-23 | 2018-09-21 | 广东伊莱斯电机有限公司 | A kind of control method improving analog loopback sampling precision |
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Application publication date: 20141224 |
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