CN111322233A - Sampling circuit and method for improving precision, compressor and air conditioning equipment - Google Patents

Abstract

The invention discloses a sampling circuit and method for improving precision, a compressor and air conditioning equipment. Wherein, this sampling circuit includes: a sampling module connected between the compressor and a reference ground, comprising: the sampling module is controlled by the digital signal processor to change the conduction state; the first input end of the operation module is connected between the compressor and the sampling module, the second input end of the operation module is connected with a reference ground, and the operation module is used for performing operation processing on the voltage output by the sampling module to obtain a sampling voltage; and the digital signal processor is connected with the operation module and controls the conduction state according to the sampling voltage subjected to operation processing. According to the invention, the total resistance value of the sampling module can be adaptively changed, and more accurate current sampling is realized when the current of the compressor is lower, so that the compressor is more accurately controlled.

Description

Sampling circuit, method, compressor and air conditioner for improving accuracy

technical field

The present invention relates to the technical field of electronic power, and in particular, to a sampling circuit, method, compressor and air conditioner with improved accuracy.

Background technique

In the existing variable frequency drive air conditioner technology, the compressor current is sampled through a single resistor. When the compressor current is smaller, the sampling voltage of the sampling resistor also becomes smaller. Due to possible superimposed interference and other reasons, under the condition that the gain of the op amp is not changed, when the compressor current is small, the accuracy of the sampled value after the op amp will be lower than that under normal conditions, which will affect the compressor in this case. control.

Aiming at the problem in the prior art that when the sampling voltage decreases with the compressor current, the sampling accuracy will become lower, and no effective solution has been proposed so far.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a sampling circuit, method, compressor, and air conditioner with improved accuracy, so as to solve the problem in the prior art that when the sampling voltage decreases with the compressor current, the sampling accuracy becomes lower.

In order to solve the above technical problems, the present invention provides a sampling circuit with improved accuracy, wherein the sampling includes: a sampling module, an arithmetic module and a digital signal processor;

The sampling module, connected between the compressor and the reference ground, includes: a first sampling branch and a second sampling branch arranged in parallel between the compressor and the reference ground, the first sampling branch and/or The second sampling branch changes the conduction state under the control of the digital signal processor;

The first input of the arithmetic module is connected between the compressor and the sampling module, the second input is connected to the reference ground, and the output is connected to the digital signal processor for sampling the sampling After the sampling voltage output by the module is processed, it is output to the digital signal processor;

The digital signal processor is connected to the operation module and the sampling module respectively, and is used for controlling the conduction state according to the sampling voltage processed by the operation.

Further, the conduction state means: the first sampling branch and the second sampling branch are selectively turned on, or all the first sampling branch and the second sampling branch are turned on. Pass.

Further, a switch is provided on the first sampling branch and/or the second sampling branch, and the switch is turned on or off under the control of the digital signal processor.

Further, the first sampling branch includes at least one first resistor, and the second sampling branch includes at least one second resistor.

Further, the first resistor and the second resistor are fixed-value resistors.

The present invention also provides a compressor, including the above-mentioned sampling circuit for providing accuracy.

The present invention also provides an air conditioner, comprising the above compressor.

The present invention also provides a sampling method for improving precision, which is applied to the above-mentioned sampling circuit for improving precision, comprising:

Get the sampled voltage value;

The conduction state of the first sampling branch and/or the second sampling branch is controlled according to the sampled voltage value.

Further, controlling the conduction state of the first sampling branch and/or the second sampling branch according to the sampled voltage value includes:

If the sampling voltage value is less than the first preset value, controlling the first sampling branch and the second sampling branch to conduct one of them;

If the sampling voltage value is greater than or equal to the first preset value, the first sampling branch and the second sampling branch are controlled to be all turned on.

Further, after controlling one of the first sampling branch and the second sampling branch to be turned on, the method further includes:

Determine whether the current sampling voltage value is greater than or equal to a second preset value; wherein, the second preset value is greater than the first preset value;

If yes, control the first sampling branch and the second sampling branch to be all turned on;

If not, continue to keep the first sampling branch and the second sampling branch alternately conducting.

Further, controlling one of the first sampling branch and the second sampling branch to be turned on includes: controlling a switch of the first sampling branch or a switch of any branch in the second sampling branch. switch off;

Controlling all of the first sampling branch and the second sampling branch to be turned on includes: controlling both the switches of the first sampling branch and the second sampling branch to be turned on.

The present invention also provides a computer-readable storage medium on which a computer program is stored, and when the program is executed by a processor, the above-mentioned sampling method for improving precision is implemented.

By applying the technical solution of the present invention, by changing the conduction state of the first sampling branch and the second sampling branch, the total resistance value of the sampling module is changed, and when the sampling voltage decreases with the compressor current, the sampling can be changed adaptively. The total resistance value of the module can achieve more accurate current sampling when the compressor current is low, so as to control the compressor more accurately.

Description of drawings

1 is a structural diagram of a sampling circuit according to an embodiment of the present invention;

2 is a structural diagram of a sampling circuit according to another embodiment of the present invention;

3 is a structural diagram of a sampling circuit according to another embodiment of the present invention;

FIG. 4 is a flowchart of a sampling method according to an embodiment of the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a," "the," and "the" as used in the embodiments of the present invention and the appended claims are intended to include the plural forms as well, unless the context clearly dictates otherwise, "a plurality" Generally at least two are included.

It should be understood that the term "and/or" used in this document is only an association relationship to describe the associated objects, indicating that there may be three kinds of relationships, for example, A and/or B, which may indicate that A exists alone, and A and B exist at the same time. B, there are three cases of B alone. In addition, the character "/" in this document generally indicates that the related objects are an "or" relationship.

It should be understood that although the terms first, second, third, etc. may be used to describe resistances in embodiments of the present invention, these resistances should not be limited by these terms. These terms are only used to distinguish different resistances. For example, the first resistor may also be referred to as the second resistor, and similarly, the second resistor may also be referred to as the first resistor without departing from the scope of the embodiments of the present invention.

Depending on the context, the words "if", "if" as used herein may be interpreted as "at" or "when" or "in response to determining" or "in response to detecting". Similarly, the phrases "if determined" or "if detected (the stated condition or event)" can be interpreted as "when determined" or "in response to determining" or "when detected (the stated condition or event)," depending on the context )" or "in response to detection (a stated condition or event)".

It should also be noted that the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion, such that a commodity or device comprising a list of elements includes not only those elements, but also those not explicitly listed other elements, or other elements inherent to such goods or devices. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in the article or device that includes the element.

The optional embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Example 1

This embodiment provides a sampling circuit with improved accuracy. FIG. 1 is a structural diagram of a sampling circuit according to an embodiment of the present invention. As shown in FIG. 1 , the sampling circuit includes a sampling module 11 , an arithmetic module 12 and a digital signal processor 13 ; The sampling module 11, connected between the compressor 14 and the reference ground, includes: a first sampling branch 111 and a second sampling branch 112 arranged in parallel between the compressor and the reference ground, the first sampling branch 111 and /or the second sampling branch 112 changes the conduction state under the control of the digital signal processor 13; the operation module 12, whose first input terminal is connected between the compressor 14 and the sampling module 11, whose second input terminal is connected For reference, its output end is connected to the digital signal processor 13, which is used to perform arithmetic processing on the sampled voltage output by the sampling module 11, and then output to the digital signal processor 13; the digital signal processor 13 is respectively connected with the arithmetic module 12 and the sampling module. 11 is connected to control the conduction state of the first sampling branch 111 and/or the second sampling branch 112 according to the sampling voltage processed by the operation, so as to realize the change of the total resistance value of the sampling module 11, wherein the conduction state is It means that one of the first sampling branch and the second sampling branch is turned on, or both the first sampling branch and the second sampling branch are turned on.

In the sampling circuit of this embodiment, by changing the conduction state of the first sampling branch and the second sampling branch, the total resistance value of the sampling module 11 is changed, and when the sampling voltage decreases with the compressor current, it can be changed adaptively. The total resistance value of the sampling module 11 realizes more accurate current sampling when the compressor current is low, so as to control the compressor more accurately.

Example 2

This embodiment provides another sampling circuit with improved accuracy. FIG. 2 is a structural diagram of a sampling circuit according to another embodiment of the present invention. In order to control the first sampling branch 111 and/or the second sampling branch 112 In the conduction state, as shown in FIG. 2 , the second sampling branch 112 is provided with a switch Q. The switch Q is connected to the second interface DSP2 of the digital signal processor and is connected to be turned on or off under the control of the digital signal processor. It should be noted that, in other embodiments of the present invention, the switch may also be set on the first sampling branch 111, and switches may also be set on both the first sampling branch 111 and the second sampling branch 112, wherein the above switch Q may be a MOSFET switch tube or an IGBT switch tube, which can be selected by those skilled in the art according to actual needs, which is not specifically limited in the present invention.

In order to realize that the total resistance value of the sampling module 11 formed by the first sampling branch 111 and the second sampling branch 112 is variable, the first sampling branch 111 includes at least one first resistor R1, and the second sampling branch 112 includes at least one first resistor R1. The second resistor R2. In this embodiment, the numbers of the first resistor R1 and the second resistor R2 are both 1. In other embodiments of the present invention, the first sampling branch 111 may include a plurality of first resistors connected in series. The resistor R1, or a plurality of first resistors R1 are combined in series and parallel to form a resistor network, wherein the conduction of each parallel branch can be controlled independently. Similarly, the second sampling branch 112 can also include multiple series The second resistor R2, or a plurality of second resistors R2 are combined in series and parallel to form a resistor network, wherein the conduction of each parallel branch can be controlled independently.

During specific implementation, in order to facilitate the analysis and calculation of the total resistance value of the sampling circuit, the first resistor R1 and the second resistor R2 are fixed-value resistors, and their resistance values are fixed.

Since the voltage output by the sampling module 11 is an analog signal, and the input signal of the digital signal processor 13 needs to be a digital signal, it is necessary to perform arithmetic processing on the voltage output by the sampling module 11 before it can be received and read by the digital signal processor 13. Therefore, the above-mentioned operation module 12 includes: an operational amplifier A; a third resistor R3, the first end of the third resistor R3 is connected between the sampling module 11 and the compressor 14, and the second end is connected to the positive phase of the above-mentioned operational amplifier A The input terminal is used to limit the input voltage of the non-inverting input terminal of the operational amplifier A to prevent the input voltage of the non-inverting input terminal of the operational amplifier A from being too high and exceeding the operating voltage of the operational amplifier A; and a fourth resistor R4, the fourth resistor is connected to the operation Between the inverting input terminal of the amplifier and the reference ground, it is used to limit the input voltage of the inverting input terminal of the operational amplifier A, so that the input voltage of the inverting input terminal is not zero, and the output terminal of the operational amplifier A is connected to the first digital signal processor. An interface DSP1.

In the above operation module 12, in order to increase the stability of the system, increase the input impedance and reduce the output impedance, it may further include: a fifth resistor R5, connected between the output end of the operational amplifier A and the inverting input end of the operational amplifier, It is used to feed back part of the output signal of operational amplifier A to its inverting input terminal to achieve the purpose of increasing system stability, increasing input impedance and reducing output impedance.

Since the above operational amplifier needs to work under a certain voltage, the operational amplifier A further includes: a third input terminal and a fourth input terminal, the third input terminal is connected to the reference ground, and the fourth input terminal is connected to the voltage source VCC for Implemented to provide operating power for operational amplifier A.

Example 3

This embodiment provides another sampling circuit with improved accuracy. FIG. 3 is a structural diagram of a sampling circuit according to another embodiment of the present invention. As shown in FIG. 3, the circuit includes: a first sampling resistor R31, a second sampling resistor R32, operational amplifier non-inverting input resistance R33, operational amplifier inverting input resistance R34, feedback resistance R35, switch Q1, operational amplifier U1-A and digital signal processor, namely DSP, wherein, the second sampling resistance R32, According to the selection of the maximum current that the switch tube Q1 can withstand, the first sampling resistor R31 is selected according to the second sampling resistor R32 and the rated current of the compressor. When the compressor current is large, the I/O port corresponding to the DSP outputs a high level , when the current of the compressor is reduced to 1/10 to 1/5 of the rated current of the compressor, the DSP determines that the sampled voltage value correspondingly becomes V1 according to the received voltage, and sets V1 as the first threshold value.

When the sampling voltage value is less than the first threshold value V1, it is determined that the compressor current is low at this time, the control switch Q1 is turned off, and only the first sampling resistor R32 is turned on, so that the sampling resistance value is increased by 5 to 10 times accordingly. The DSP correspondingly changes the software value of the sampling voltage to increase the voltage of the non-inverting input terminal of the operational amplifier, thereby improving the sampling accuracy.

In order to prevent the operational amplifier from entering saturation, the second threshold V2 is set, which is slightly lower than the operational amplifier power supply voltage VCC. For example, if VCC is 3.3V, the second threshold V2 can be set to 3.0V. When the control switch Q1 Turn off, only after the first sampling resistor R32 is turned on, when the sampling voltage value rises to a certain threshold V2, it is judged that the compressor current is out of the small current state, the I/O port corresponding to the DSP outputs a high level, and the switch tube is turned on. Q1, reduce the sampling resistance to prevent the op amp from entering saturation.

In this embodiment, when the compressor current is relatively large, the switch tube Q1 is in a conducting state. The first sampling resistor R31 and the second sampling resistor R32 are in parallel state. At this time, the sampling resistance value is R31//R32=R31*R32/(R31+R32), and the compressor current is reduced to 1/10 of the rated current of the compressor to At 1/5, the switch tube Q1 is in the off state, and the sampling resistance value is R1 at this time, that is, R31//R32=R1. Since R31>R31*R32/(R31+R32), when the compressor current is reduced to the compressor When the rated current is 1/10 to 1/5, the sampling resistance is larger, which can increase the voltage of the non-inverting input terminal of the op amp.

In this embodiment, in order to reduce the current flowing through the switch tube Q1 when the first sampling resistor R31 and the second sampling resistor R32 are connected in parallel, the resistance value of R32 can be set larger and the resistance value of R31 is smaller, so that the first sampling resistor R31 and the second sampling resistor R32 are connected in parallel. When the sampling resistor R31 and the second sampling resistor R32 are connected in parallel, the current I flowing through the switch tube Q1=compressor current×R31/(R31+R32).

In this embodiment, when the current of the branch where the second sampling resistor R32 is located is small, for example, below 6V, the switch Q1 can be selected as a MOSFET; when the current of the branch where the second sampling resistor R32 is located is relatively large, the switch can be selected as an IGBT .

Example 4

This embodiment provides a compressor, including the sampling circuit with improved accuracy in the above-mentioned embodiments.

Example 5

This embodiment provides an air conditioner, including the compressor in Embodiment 4, which is used to improve the sampling accuracy of the compressor, so as to implement more accurate current sampling when the compressor current is low, so as to perform more accurate current sampling on the compressor. control.

Example 6

This embodiment provides a sampling method for improving accuracy, which is applied to the above-mentioned sampling circuit for improving accuracy. FIG. 4 is a flowchart of the sampling method according to an embodiment of the present invention. As shown in FIG. 4 , the method includes:

S101, obtaining a sampled voltage value;

S102: Control the conduction state of the first sampling branch and/or the second sampling branch according to the sampled voltage value.

In order to control the first sampling branch and the second sampling branch to be selectively turned on or all of them are turned on according to the sampled voltage value, step S102 specifically includes: if the sampled voltage value is less than the first preset value, controlling the first sampling branch Select one to conduct with the second sampling branch to increase the resistance value of the sampling module, thereby increasing the sampling voltage; if the sampling voltage value is greater than or equal to the first preset value, control the first sampling branch and the second sampling branch All are turned on to reduce the resistance value of the sampling module, thereby reducing the sampling voltage.

If the sampling voltage is greater than or equal to the power supply voltage of the operation module, it will lead to saturation of the operation module. In order to avoid this phenomenon, after controlling the first sampling branch and the second sampling branch to select one to conduct, the method further includes: judging the current Whether the sampling voltage value is greater than or equal to the second preset value; wherein, the second preset value is greater than the first preset value, and the second threshold value is set according to the power supply voltage of the computing module; For the power supply voltage, it is necessary to control all the first sampling branch and the second sampling branch to be turned on, and reduce the sampling voltage; if not, continue to keep the first sampling branch and the second sampling branch conductive.

In a specific implementation, controlling the first sampling branch and the second sampling branch to selectively turn on includes: controlling the switch of the first sampling branch or the switch of any branch in the second sampling branch to turn off; controlling the first sampling branch to turn off; The first sampling branch and the second sampling branch are all turned on, including: controlling the switches of the first sampling branch and the second sampling branch to be turned on.

In the sampling circuit of this embodiment, the total resistance value of the sampling module is changed by changing the conduction state of the first sampling branch and the second sampling branch. When the sampling voltage decreases with the compressor current, the sampling can be changed adaptively. The total resistance value of the module can achieve more accurate current sampling when the compressor current is low, so as to control the compressor more accurately.

Example 7

This embodiment provides a computer-readable storage medium on which a computer program is stored, and when the program is executed by a processor, the above-mentioned sampling method for improving precision is implemented.

From the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and certainly can also be implemented by hardware. Based on this understanding, the above-mentioned technical solutions can be embodied in the form of software products in essence or the parts that make contributions to the prior art, and the computer software products can be stored in computer-readable storage media, such as ROM/RAM, magnetic Disks, optical discs, etc., include instructions for causing a computer device (which may be a personal computer, server, or network device, etc.) to perform the methods of various embodiments or portions of embodiments.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that it can still be The technical solutions described in the foregoing embodiments are modified, or some technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (11)

1. A sampling circuit is characterized by comprising a sampling module, an operation module and a digital signal processor;

the sampling module is connected between the compressor and a reference ground and comprises: the first sampling branch and the second sampling branch are arranged between the compressor and a reference ground in parallel, and the first sampling branch and/or the second sampling branch change the conduction state under the control of the digital signal processor;

the first input end of the operation module is connected between the compressor and the sampling module, the second input end of the operation module is connected with a reference ground, and the output end of the operation module is connected with the digital signal processor and is used for outputting the sampling voltage output by the sampling module to the digital signal processor after operation processing;

the digital signal processor is respectively connected with the operation module and the sampling module and is used for controlling the conduction state according to the sampling voltage subjected to operation processing.

2. The sample according to claim 1,

the on state is: and the first sampling branch circuit and the second sampling branch circuit are selected to be conducted, or the first sampling branch circuit and the second sampling branch circuit are all conducted.

3. The sample according to claim 1, wherein a switch is provided on the first sampling branch and/or the second sampling branch, the switch being turned on or off under the control of the digital signal processor.

4. The sample according to claim 1, wherein said first sampling branch comprises at least a first resistor and said second sampling branch comprises at least a second resistor.

5. The sample according to claim 4, wherein said first and second resistances are fixed-value resistances.

6. A compressor, characterized by comprising a sampling circuit according to any one of claims 1 to 5.

7. An air conditioning apparatus, characterized by comprising the compressor of claim 6.

8. A sampling method applied to the sampling circuit according to any one of claims 1 to 5, comprising:

acquiring a sampling voltage value;

and controlling the conduction state of the first sampling branch and/or the second sampling branch according to the sampling voltage value.

9. The method of claim 8, wherein controlling the conducting state of the first sampling branch and/or the second sampling branch according to the sampled voltage value comprises:

if the sampling voltage value is smaller than a first preset value, controlling one of the first sampling branch circuit and the second sampling branch circuit to be conducted;

and if the sampling voltage value is greater than or equal to the first preset value, controlling the first sampling branch and the second sampling branch to be completely conducted.

10. The method of claim 9, wherein after controlling the first sampling branch and the second sampling branch to be alternatively turned on, the method further comprises:

judging whether the current sampling voltage value is greater than or equal to a second preset value; wherein the second preset value is greater than the first preset value;

if yes, controlling the first sampling branch and the second sampling branch to be conducted completely;

if not, continuously keeping the first sampling branch and the second sampling branch to be alternatively conducted.

11. A computer-readable storage medium, on which a computer program is stored, which program, when being executed by a processor, carries out the sampling method according to any one of claims 8 to 10.

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