Sampling circuit, method, circuit board, sampling device and air conditioner

Abstract

The application discloses a sampling circuit, a method, a circuit board, a sampling device and an air conditioner. The sampling circuit comprises one or more than two sampling modules arranged in parallel and a signal processing module connected with the output end of the sampling module, and the output end of the signal processing module is connected with a motor. The sampling module is used for sampling one-phase electric signals output by the motor, and each sampling module is used for sampling electric signals of different phases. The signal processing module is used for adjusting the current value of the sampling signal by inputting excitation current to the motor according to the sampling signal. The sampling signal is the signal output by the sampling module according to the sampled electric signal. The excitation current can compensate the current value of the electric signal output by the motor without affecting the rotating speed of the motor, so as to adjust the current value of the sampling signal. The sampling circuit can accurately sample the electric signal output by the motor without arranging a Hall element or an operational amplifier, and the cost can be effectively reduced.

Description

Technical Field

[0001] The embodiments of the present invention relate to, but are not limited to, the field of electronics, and particularly to a sampling circuit, method, circuit board, sampling device, and air conditioner. Background Technology

[0002] Air conditioner indoor units have high noise requirements, and currently, the market mainly uses brushless DC motors with built-in feedback to replace the original AC motors. At present, manufacturers using brushless DC motors with built-in feedback often use Hall effect sensors as the motor position detection element because the MCU cannot sample the negative voltage of the signal output from the brushless DC motor. This can be combined with a sampling resistor to detect the motor's phase current, or the sampling circuit can be externalized, amplifying the sampled signal through an operational amplifier to achieve accurate sampling of the motor's electrical signal. However, the solution using Hall effect sensors as the motor position detection element increases the cost of the motor, and due to the limited internal space of the motor, heat dissipation of the Hall effect sensor is difficult, leading to a higher failure rate in actual use. The solution using an operational amplifier also suffers from high cost. Summary of the Invention

[0003] The main objective of this invention is to provide a sampling circuit, method, circuit board, sampling device, and air conditioner that can accurately sample the electrical signals of a motor and effectively reduce costs.

[0004] In a first aspect, embodiments of the present invention provide a sampling circuit applied to the motor of an air conditioner, the sampling circuit comprising:

[0005] One or more sampling modules are connected in parallel, wherein the sampling module is used to sample the electrical signal of one phase of the motor output, and each sampling module is used to sample the electrical signal of a different phase;

[0006] The signal processing module has its input terminal connected to the output terminal of the sampling module and its output terminal connected to the motor. The signal processing module is used to input excitation current to the motor according to the sampling signal in order to adjust the current value of the sampling signal. The sampling signal is the signal output by the sampling module based on the sampled electrical signal.

[0007] The technical solution of the first aspect of the present invention has at least one of the following advantages or beneficial effects:

[0008] The sampling circuit includes one or more sampling modules connected in parallel and a signal processing module connected to the output of the sampling modules. The output of the signal processing module is connected to the motor. Each sampling module samples the electrical signal of one phase of the motor output, and each sampling module samples the electrical signal of a different phase. The signal processing module inputs an excitation current to the motor based on the sampled signal to adjust the current value of the sampled signal. The sampled signal is the signal output by the sampling module based on the electrical signal. By inputting an excitation current to the motor through the signal processing module, the current value of the motor output electrical signal can be compensated without affecting the motor speed, thereby adjusting the current value of the compensated sampled signal. This sampling circuit can accurately sample the electrical signal output by the motor without the need for Hall elements or operational amplifiers, and can effectively reduce costs.

[0009] Optionally, the sampling module includes a switch group, a sampling unit connected to the switch group, and a biasing unit for biasing the electrical signal. One end of the biasing unit is connected to the connection terminal of the sampling unit and the switch group, and the other end is connected to the input terminal of the signal processing module.

[0010] The input motor current can be controlled by a switch group, and the electrical signal output by the motor can be sampled by a sampling unit. The sampled electrical signal is then biased by a bias unit to ensure that the voltage value of the sampled electrical signal is positive. A sampling signal is generated and output, which facilitates signal acquisition and analysis by the microcontroller unit.

[0011] Optionally, the bias unit includes a bias power supply, a first voltage divider resistor, and a second voltage divider resistor. One end of the first voltage divider resistor is connected to the bias power supply, and the other end is connected to one end of the second voltage divider resistor. The other end of the second voltage divider resistor is connected to the connection terminal of the switch group and the sampling unit. The connection terminal between the first voltage divider resistor and the second voltage divider resistor is connected to the input terminal of the signal processing module.

[0012] By programming the combination of power supply, first voltage divider resistor and second voltage divider resistor, the sampled electrical signal can be processed to ensure that the voltage values ​​of the sampled electrical signal are all positive, thereby generating a sampled signal and outputting it, which facilitates signal acquisition and analysis by the microcontroller unit.

[0013] Optionally, the switch group includes a first switch component and a second switch component connected in series with the first switch component, and the connection end of the first switch component and the second switch component is connected to the input end of the motor.

[0014] The first switching component, the second switching component, and the sampling resistor are connected in sequence. By controlling the on and off states of the first and second switching components, the duration of the current passing through the sampling resistor can be controlled. This sampling circuit can accurately sample the electrical signal output by the motor without the need for Hall elements or operational amplifiers, and can effectively reduce costs.

[0015] Optionally, the resistance value of the first voltage divider resistor is equal to the resistance value of the second voltage divider resistor.

[0016] This ensures that the voltage division ratio of the sampled signals is the same when the sampling module is in a static state and when it is in a dynamic state, thereby improving the calculation efficiency of the waveforms generated by the sampled signals from the three sampling modules.

[0017] Optionally, the resistance value of the sampling resistor is smaller than that of the first voltage divider resistor, and the resistance value of the sampling resistor is smaller than that of the second voltage divider resistor.

[0018] Setting the sampling resistor to a small value will prevent the motor from operating normally due to voltage division caused by the sampling resistor, and will also prevent the voltage value for signal amplification from being too small due to voltage division caused by the sampling resistor.

[0019] Optionally, the resistance value of the sampling resistor is less than or equal to 10 ohms, the resistance value of the first voltage divider resistor is greater than or equal to 1000 ohms, and the resistance value of the second voltage divider resistor is greater than or equal to 1000 ohms.

[0020] Secondly, this invention also provides a sampling method applied to a signal processing module of a sampling circuit. The sampling circuit further includes one or more sampling modules connected in parallel. The sampling modules are used to sample the electrical signal of one phase output by the motor, and each sampling module is used to sample the electrical signal of a different phase.

[0021] The input terminal of the signal processing module is connected to the output terminal of the sampling module, and the output terminal of the signal processing module is connected to the motor.

[0022] The method includes:

[0023] Acquire the sampled signal from the output of the sampling module;

[0024] The excitation current is input to the motor according to the current value of the sampled signal, so as to adjust the current value of the sampled signal.

[0025] The technical solution of the second aspect of the present invention has at least one of the following advantages or beneficial effects:

[0026] The signal processing module can acquire the sampling signal from the output of the sampling module, and then input the excitation current to the motor according to the current value of the sampling signal to adjust the current value of the electrical signal output by the motor. This adjusts the current value of the sampling signal generated by the sampling circuit based on the electrical signal, enabling accurate sampling of the motor's electrical signal while effectively reducing costs.

[0027] Optionally, the step of inputting an excitation current to the motor based on the current value of the sampled signal to adjust the current value of the sampled signal includes:

[0028] The current value of the excitation current input to the motor is determined based on the current value of the sampled signal;

[0029] The excitation current is input to the motor to adjust the electrical signal output by the motor, so that the current value of the sampling signal generated by the sampling circuit based on the electrical signal is greater than or equal to a first current threshold.

[0030] The signal processing module can determine the excitation current value based on the acquired sampling current value. Then, the signal processing module can output the determined excitation current to the motor to adjust the electrical signal output by the motor. This ensures that the current value of the sampling signal generated by the sampling circuit based on the electrical signal is greater than or equal to the first current threshold, thereby achieving accurate sampling of the motor's electrical signal while effectively reducing costs.

[0031] Optionally, it also includes:

[0032] When the current value of the sampled signal is equal to the second current threshold, the current value of the excitation current is adjusted;

[0033] The excitation current is input to the motor to adjust the electrical signal output by the motor, so that the current value of the sampling signal generated by the sampling circuit based on the electrical signal is less than or equal to the second current threshold.

[0034] When the current value of the sampled signal acquired by the signal processing module is equal to the second current threshold, the signal processing module can adjust the current value of the excitation current to adjust the electrical signal output by the motor. This makes the current value of the sampled signal generated by the sampling circuit based on the electrical signal less than or equal to the second current threshold, thus enabling accurate sampling of the motor's electrical signal while effectively reducing costs.

[0035] Thirdly, embodiments of the present invention also provide a circuit board, including the sampling circuit of the first aspect.

[0036] The technical solution of the third aspect of the present invention has at least one of the following advantages or beneficial effects:

[0037] The sampling device includes a sampling circuit, which may include one or more sampling modules connected in parallel and a signal processing module connected to the output of the sampling modules. The output of the signal processing module is connected to the motor. Each sampling module samples the electrical signal of one phase of the motor output, and each sampling module samples the electrical signal of a different phase. The signal processing module inputs an excitation current to the motor based on the sampled signal to adjust the current value of the sampled signal. The sampled signal is the signal output by the sampling module based on the sampled electrical signal. By inputting an excitation current to the motor through the signal processing module, the current value of the motor output electrical signal can be compensated without affecting the motor speed, thereby adjusting the current value of the compensated sampled signal. This sampling circuit can accurately sample the electrical signal output by the motor without the need for Hall elements or operational amplifiers, and can effectively reduce costs.

[0038] Fourthly, embodiments of the present invention also provide a sampling device, including the sampling circuit of the first aspect, or the circuit board of the third aspect.

[0039] The technical solution of the fourth aspect of the present invention has at least one of the following advantages or beneficial effects:

[0040] The sampling device includes a circuit board, which in turn includes a sampling circuit. The sampling circuit may include one or more sampling modules connected in parallel and a signal processing module connected to the output of each sampling module. The output of the signal processing module is connected to the motor. Each sampling module samples the electrical signal of one phase of the motor output, and each sampling module samples the electrical signal of a different phase. The signal processing module inputs an excitation current to the motor based on the sampled signal to adjust the current value of the sampled signal. The sampled signal is the signal output by the sampling module based on the electrical signal. By inputting an excitation current to the motor through the signal processing module, the current value of the motor output electrical signal can be compensated without affecting the motor speed, thereby adjusting the current value of the compensated sampled signal. This sampling circuit can accurately sample the motor output electrical signal without the need for Hall elements or operational amplifiers, and it effectively reduces costs.

[0041] Fifthly, embodiments of the present invention also provide an air conditioner, including: a sampling circuit of the first aspect, or a circuit board including the third aspect, or a sampling device including the fourth aspect.

[0042] The technical solution of the fifth aspect of the present invention has at least one of the following advantages or beneficial effects:

[0043] The air conditioner includes a sampling device, which comprises a circuit board containing a sampling circuit. The sampling circuit can have one or more sampling modules connected in parallel and a signal processing module connected to the output of each sampling module. The output of the signal processing module is connected to a motor. Each sampling module samples the electrical signal of one phase of the motor output, and each sampling module samples the electrical signal of a different phase. The signal processing module inputs an excitation current to the motor based on the sampled signal to adjust the current value of the sampled signal. The sampled signal is the signal output by the sampling module based on the sampled electrical signal. By inputting an excitation current to the motor through the signal processing module, the current value of the motor output electrical signal can be compensated without affecting the motor speed, thereby adjusting the current value of the compensated sampled signal. This sampling circuit can accurately sample the motor output electrical signal without the need for Hall elements or operational amplifiers, and can effectively reduce costs.

[0044] In a sixth aspect, embodiments of the present invention also provide an air conditioner, including: a sampling method as described in the second aspect.

[0045] The technical solution of the sixth aspect of the present invention has at least one of the following advantages or beneficial effects:

[0046] The signal processing module in the air conditioner can acquire the sampling signal from the output of the sampling module, and then input the excitation current to the motor according to the current value of the sampling signal to adjust the current value of the electrical signal output by the motor. This adjusts the current value of the sampling signal generated by the sampling circuit based on the electrical signal, enabling accurate sampling of the motor's electrical signal while effectively reducing costs. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the sampling circuit provided in one embodiment of the present invention;

[0048] Figure 2 This is a schematic diagram of the sampling circuit provided in another embodiment of the present invention;

[0049] Figure 3 This is a schematic diagram of the sampling circuit provided in another embodiment of the present invention;

[0050] Figure 4 This is a flowchart of a sampling method provided in one embodiment of the present invention;

[0051] Figure 5 This is a flowchart illustrating the adjustment of the excitation current value in a sampling method provided by an embodiment of the present invention;

[0052] Figure 6 This is another flowchart illustrating the adjustment of the excitation current value in the sampling method provided in one embodiment of the present invention;

[0053] Figure 7 This is a schematic diagram of the circuit board structure provided in one embodiment of the present invention;

[0054] Figure 8 This is a schematic diagram of the sampling device provided in one embodiment of the present invention;

[0055] Figure 9 This is a schematic diagram of the structure of an air conditioner provided in one embodiment of the present invention;

[0056] Figure 10 This is a schematic diagram of the structure of an air conditioner provided in another embodiment of the present invention. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0058] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0059] It should be noted that although functional modules are divided in the device schematic diagram and the logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the device or the order in the flowchart.

[0060] This embodiment provides a sampling circuit, method, circuit board, sampling device, and air conditioner, applicable to air conditioners. The sampling circuit includes one or more sampling modules connected in parallel and a signal processing module connected to the output of each sampling module. The output of the signal processing module is connected to a motor. Each sampling module samples the electrical signal of one phase of the motor output, and each sampling module samples the electrical signal of a different phase. The signal processing module inputs an excitation current to the motor based on the sampled signal to adjust the current value of the sampled signal. The sampled signal is the signal output by the sampling module based on the electrical signal. By inputting an excitation current to the motor through the signal processing module, the current value of the motor output electrical signal can be compensated without affecting the motor speed, thereby adjusting the current value of the compensated sampled signal. This sampling circuit can accurately sample the electrical signal output by the motor without using Hall elements or operational amplifiers, and can effectively reduce costs.

[0061] The embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0062] In one embodiment, refer to Figure 1 , Figure 1 This is a schematic diagram of a sampling circuit provided in an embodiment of the present invention. The sampling circuit is applied to an air conditioner and includes one or more sampling modules 110 connected in parallel and a signal processing module 120 connected to the output terminal of the sampling module 110. The output terminal of the signal processing module 120 is connected to a motor M. The sampling module 110 is used to sample the electrical signal of one phase output by the motor M, and each sampling module 110 is used to sample the electrical signals output by the motor M in different phases. The signal processing module 120 is used to input an excitation current to the motor M according to the sampling signal to adjust the current value of the sampling signal. The sampling signal is the signal output by the sampling module 110 based on the electrical signal. The excitation current can be input to the motor M through the signal processing module 120. The excitation current can compensate for the current value of the electrical signal output by the motor M without affecting the speed of the motor M, thereby adjusting and compensating for the current value of the sampling signal. This sampling circuit can achieve accurate sampling of the electrical signal output by the motor M without the need for Hall elements or operational amplifiers, and can effectively reduce costs.

[0063] In one embodiment, both the sampling current and the electrical signal of the motor M can include armature current and excitation current. Normally, the excitation current of the permanent magnet synchronous motor is 0. If the current value of the sampling current is less than the first current threshold, the armature current can be left unadjusted so as not to affect the speed of the motor M. The signal processing module 120 can adjust the excitation current and then input the excitation current to the motor M to increase the current value of the electrical signal output by the motor M, so that the current value of the sampling current is greater than or equal to the first current threshold, thereby further improving the sampling accuracy.

[0064] In one embodiment, as the rotational speed of the motor M increases, the armature current also increases. When the sampling current value is equal to the second current threshold, the signal processing module 120 can reduce the excitation current input to the motor M, thereby reducing the current value of the electrical signal output by the motor M, so that the current value of the sampling signal is less than or equal to the second current threshold.

[0065] It should be noted that the signal processing module 120 can be set in the microcontroller unit or set independently; this embodiment does not specifically limit it.

[0066] It should be noted that both the first current threshold and the second current threshold can be set according to the actual situation of the target motor M being sampled, and this embodiment does not impose any specific limitations on them.

[0067] It should be noted that when the current value of the sampled current obtained by the signal processing module 120 is greater than the first current threshold and less than the second current threshold, the current value of the armature current increases with the increase of the speed of the motor M. The adjustment law of the current value of the excitation current input by the signal processing module 120 to the motor can be a law of decreasing with the increase of the speed of the motor M. The current value of the excitation current input by the signal processing module 120 to the motor can also be a fixed current value. This embodiment does not make specific limitations on it.

[0068] It should be noted that when the current value of the sampled current obtained by the signal processing module 120 reaches the second current threshold, and the speed of the motor M needs to continue to increase, the signal processing module 120 can adjust the current value of the excitation current input to the motor to decrease. That is, in this case, the adjustment law of the excitation current value can be the law of decreasing as the speed of the motor M increases, so that the current value of the sampled current can be adjusted to not exceed the second current threshold.

[0069] It should be noted that the adjustment and change of the excitation current value can also be explained using a coordinate graph. For example, in a coordinate graph where the vertical axis is the current value and the horizontal axis is the motor speed, the armature current is a curve where the current value is directly proportional to the speed. The curve for adjusting the excitation current value can be a curve that gradually decreases to 0 from the first current value set when the motor M outputs its lowest speed (a curve where the current value is inversely proportional to the speed). Alternatively, it can be a curve composed of a first straight line and a second straight line. The first straight line is a straight line that starts from the second current value set when the motor M outputs its lowest speed and remains at the second current value until the sampled current reaches the second current threshold (i.e., the first straight line is a straight line parallel to the horizontal axis). The second straight line is a straight line that gradually decreases from the second current value to 0 when the sampled current reaches the second current threshold (i.e., the second straight line is a curve where the current value is inversely proportional to the speed). As long as the current value requirements for compensating the sampled current are met, this embodiment does not specifically limit the shape of the curve for adjusting the excitation current.

[0070] It should be noted that the excitation current adjustment curve can also be set in a quadrant where the current value is negative and the target speed value is positive. In this case, the excitation current adjustment curve can be a compensation curve that is mirror-symmetrical to the compensation curve set in a quadrant where both the current value and the target speed value are positive.

[0071] In one embodiment, refer to Figure 2The sampling module may include a switch group SG, a sampling unit SA connected to the switch group SG, and a bias unit for biasing the sampled signal voltage. The bias unit is connected to the connection terminals of the switch group SG and the sampling unit SA. The output terminal of the signal processing module 120 is connected to the motor M. The sampling module can be used to sample the electrical signal of one phase of the motor M. The sampling circuit also includes a signal processing module 120 connected to the programming unit. The signal processing module 120 can sample the electrical signal after it has been biased by the bias unit. The bias unit may include a bias power supply VCC, a first voltage divider resistor R1, and a second voltage divider resistor R2. One end of the first voltage divider resistor R1 is connected to the bias power supply VCC, and the other end is connected to one end of the second voltage divider resistor R2. The other end of the second voltage divider resistor R2 is connected to the connection terminals of the switch group SG and the sampling unit SA. The connection terminal between the first voltage divider resistor R1 and the second voltage divider resistor R2 is the sampling output terminal. By sequentially setting the bias power supply VCC, the first voltage divider resistor R1, and the second voltage divider resistor R2 in the bias unit, the sampling circuit of this structure biases the electrical signal of the motor collected by the sampling unit, so that all the sampled electrical signals are positive, generating a sampling signal. The signal processing module 120 inputs excitation current to the motor M according to the sampling signal, which can compensate the current value of the electrical signal output by the motor M without affecting the speed of the motor M, thereby adjusting the current value of the compensation sampling signal. This sampling circuit can accurately sample the electrical signal output by the motor M without setting Hall elements or operational amplifiers, and can effectively reduce costs.

[0072] It should be noted that the sampling circuit can be used to collect electrical signals from a single-phase motor, a three-phase motor, or a four-phase motor; this embodiment does not impose any specific limitations. For example, when the sampling circuit is used to collect electrical signals from a three-phase motor, three parallel sampling modules can be set up. These three sampling modules can be designated as a first sampling module, a second sampling module, and a third sampling module. The first sampling module can be connected to the U terminal of the motor, the second sampling module can be connected to the V terminal of the motor, and the third sampling module can be connected to the V terminal of the motor.

[0073] It should be noted that the voltage provided by the bias power supply VCC can be 5V or 12V, and this embodiment does not specifically limit it.

[0074] It should be noted that the resistance value of the first voltage divider resistor R1 can be equal to the resistance value of the second voltage divider resistor R2, or it can be different from the resistance value of the second voltage divider resistor R2. This embodiment does not impose specific restrictions on the ratio of the resistance values ​​of the first voltage divider resistor R1 and the second voltage divider resistor R2. When the resistance value of the first voltage divider resistor R1 can be equal to the resistance value of the second voltage divider resistor R2, the voltage division ratio of the sampled signal in the static and dynamic states of the sampling module can be the same, which can improve the calculation efficiency of the signal processing module 120 for the waveforms generated by the sampled signals from the three sampling modules.

[0075] The bias unit may also include a filtering unit, which is used to filter out interference signals in the sampled signal. The filtering unit is connected to the connection terminal of the first voltage divider resistor R1 and the second voltage divider resistor R2. By setting the filtering unit in the bias unit, the sampled signal after the voltage is boosted by the bias unit can be filtered, so that the sampled signal retains the useful electrical signal for indicating the motor status and improves the accuracy of the acquired signal.

[0076] It should be noted that the filtering unit can be a capacitor filtering circuit or an LC (inductor, capacitor) filtering circuit; this embodiment does not impose a specific limitation. When the filtering unit can be a capacitor filtering circuit, the filtering unit can be a single capacitor. One end of the capacitor is connected to the connection terminal of the first voltage divider resistor R1 and the second voltage divider resistor R2, and the other end is grounded. Since the acquired signal is an AC signal, the acquired signal can be filtered through the capacitor-grounded circuit structure, so that the sampled signal retains the useful electrical signal for representing the motor condition, improving the accuracy of the acquired signal and effectively reducing the cost of the sampling circuit.

[0077] It should be noted that the capacitor can be an electrolytic capacitor, but this embodiment does not limit it to that specific type. An electrolytic capacitor includes a positive terminal and a negative terminal. The positive terminal is a metal foil (aluminum or tantalum), and the oxide film (aluminum oxide or tantalum pentoxide) in close contact with the metal is the dielectric. The negative terminal is composed of a conductive material, an electrolyte (which can be liquid or solid), and other materials. In use, the positive and negative terminals of the electrolytic capacitor must be correctly connected according to the circuit.

[0078] It should be noted that the electrolytic capacitor may include leaded aluminum electrolytic capacitors, horn-shaped aluminum electrolytic capacitors, bolt-type aluminum electrolytic capacitors, and solid aluminum electrolytic capacitors; this embodiment does not specifically limit them.

[0079] In one embodiment, reference is made to Figure 3The sampling circuit is applied to a three-phase motor M. The sampling circuit includes a first sampling module, a second sampling module, and a third sampling module. The first sampling module can be connected to the U terminal of the three-phase motor M, the second sampling module can be connected to the V terminal of the three-phase motor M, and the third sampling module can be connected to the V terminal of the three-phase motor M. The signal processing module 120 is provided with a first input terminal, a second input terminal, a third input terminal, a first output terminal corresponding to the first input terminal, a second output terminal corresponding to the second input terminal, and a third output terminal corresponding to the third input terminal. The first input terminal is connected to the first sampling output terminal of the first sampling module, the second input terminal is connected to the second sampling output terminal of the second sampling module, and the second input terminal is connected to the second sampling output terminal of the second sampling module.

[0080] The first sampling module includes a first switch group, a first sampling unit, and a first bias unit. The first switch group includes a first switching component and a second switching component. The first sampling unit includes a first sampling resistor SR1. The first bias unit includes a bias power supply VCC, a first voltage divider resistor R1, a second voltage divider resistor R2, and a first capacitor C1. The first switching component includes a first N-type MOSFET Q1 and a first diode connected in reverse parallel with the first N-type MOSFET Q1. The second switching component includes a second N-type MOSFET Q2 and a second diode connected in reverse parallel with the second N-type MOSFET Q2. The source of the first N-type MOSFET Q1 is connected to the input power supply P. The drain of the first N-type MOSFET Q1 is connected to the source of the second N-type MOSFET Q2 and the U terminal of the three-phase motor M. The drain of the second N-type MOSFET Q2 is connected to ground through the first sampling resistor SR1. The gates of the first N-type MOSFET Q1 and the second N-type MOSFET Q2 are connected to the control module CM. One end of the first voltage divider resistor R1 is connected to the bias power supply VCC, and the other end is connected to one end of the second voltage divider resistor R2. The other end of the second voltage divider resistor R2 is connected to the drain of the second N-type MOSFET Q2. One end of the first capacitor C1 is connected to the junction of the first voltage divider resistor R1 and the second voltage divider resistor R2, and the other end is grounded. The junction between the first voltage divider resistor R1 and the second voltage divider resistor R2 is the first sampling output terminal. The resistance value of the first sampling resistor SR1 is much smaller than the resistance values ​​of the first voltage divider resistor R1 and the second voltage divider resistor R2, while the resistance values ​​of the first voltage divider resistor R1 and the second voltage divider resistor R2 are equal.

[0081] The second sampling module includes a second switch group, a second sampling unit, and a second bias unit. The second switch group includes a third switch component and a fourth switch component. The second sampling unit includes a second sampling resistor SR2. The second bias unit includes a bias power supply VCC, a third voltage divider resistor R3, a fourth voltage divider resistor R4, and a second capacitor C2. The third switch component includes a third N-type MOSFET Q3 and a third diode connected in reverse parallel with the third N-type MOSFET Q3. The fourth switch component includes a fourth N-type MOSFET Q4 and a fourth diode connected in reverse parallel with the fourth N-type MOSFET Q4. The source of the third N-type MOSFET Q3 is connected to the input power supply P. The drain of the third N-type MOSFET Q3 is connected to the source of the fourth N-type MOSFET Q4 and the V terminal of the three-phase motor M, respectively. The drain of the fourth N-type MOSFET Q4 is connected to ground through the second sampling resistor SR2. The gates of the third N-type MOSFET Q3 and the fourth N-type MOSFET Q4 are connected to the control module CM. One end of the third voltage divider resistor R3 is connected to the bias power supply VCC, and the other end is connected to one end of the fourth voltage divider resistor R4. The other end of the fourth voltage divider resistor R4 is connected to the drain of the fourth N-type MOSFET Q4. One end of the second capacitor C2 is connected to the junction of the third and fourth voltage divider resistors R3 and R4, and the other end is grounded. The junction between the third and fourth voltage divider resistors R3 and R4 is the second sampling output terminal. The resistance value of the second sampling resistor SR2 is much smaller than the resistance values ​​of the third and fourth voltage divider resistors R3 and R4, respectively. The resistance values ​​of the third and fourth voltage divider resistors R3 and R4 are equal.

[0082] The third sampling module includes a third switch group, a third sampling unit, and a third bias unit. The third switch group includes a fifth switch component and a sixth switch component. The third sampling unit includes a third sampling resistor SR3. The third bias unit includes a bias power supply VCC, a fifth voltage divider resistor R5, a sixth voltage divider resistor R6, and a third capacitor C3. The fifth switch component includes a fifth N-type MOSFET Q5 and a fifth diode connected in reverse parallel with the fifth N-type MOSFET Q5. The sixth switch component includes a sixth N-type MOSFET Q6 and a sixth diode connected in reverse parallel with the sixth N-type MOSFET Q6. The source of the fifth N-type MOSFET Q5 is connected to the input power supply P. The drain of the fifth N-type MOSFET Q5 is connected to the source of the sixth N-type MOSFET Q6 and the W terminal of the three-phase motor M, respectively. The drain of the sixth N-type MOSFET Q6 is connected to ground through the third sampling resistor SR3. The gates of the fifth N-type MOSFET Q5 and the sixth N-type MOSFET Q6 are connected to the control module CM. One end of the fifth voltage divider resistor R5 is connected to the bias power supply VCC, and the other end is connected to one end of the sixth voltage divider resistor R6. The other end of the sixth voltage divider resistor R6 is connected to the drain of the sixth N-type MOSFET Q6. One end of the third capacitor C3 is connected to the junction of the fifth and sixth voltage divider resistors R5 and R6, and the other end is grounded. The junction between the fifth and sixth voltage divider resistors R5 and R6 is the third sampling output terminal. The resistance value of the third sampling resistor SR3 is much smaller than the resistance values ​​of the fifth and sixth voltage divider resistors R5 and R6, respectively. The resistance values ​​of the fifth and sixth voltage divider resistors R5 and R6 are equal.

[0083] It should be noted that the first switching component and the second switching component can be high-frequency switches, MOSFETs, IGBTs (Insulated Gate Bipolar Transistors), or IPMs (Intelligent Power Modules). This embodiment does not specifically limit them.

[0084] It should be noted that the capacitor can be an electrolytic capacitor, but this embodiment does not limit it to that specific type. An electrolytic capacitor includes a positive terminal and a negative terminal. The positive terminal is a metal foil (aluminum or tantalum), and the oxide film (aluminum oxide or tantalum pentoxide) in close contact with the metal is the dielectric. The negative terminal is composed of a conductive material, an electrolyte (which can be liquid or solid), and other materials. In use, the positive and negative terminals of the electrolytic capacitor must be correctly connected according to the circuit.

[0085] It should be noted that the electrolytic capacitor may include leaded aluminum electrolytic capacitors, horn-shaped aluminum electrolytic capacitors, bolt-type aluminum electrolytic capacitors, and solid aluminum electrolytic capacitors; this embodiment does not specifically limit them.

[0086] It should be noted that the voltage provided by the bias power supply VCC can be 5V or 12V, and this embodiment does not specifically limit it.

[0087] It should be noted that the resistance value of the first voltage divider resistor R1 can be equal to the resistance value of the second voltage divider resistor R2, or the resistance value of the first voltage divider resistor R1 can be different from the resistance value of the second voltage divider resistor R2. In this embodiment, there is no specific limitation on the ratio of the resistance values ​​of the first voltage divider resistor R1 and the second voltage divider resistor R2.

[0088] It should be noted that the resistance value of the third voltage divider resistor R3 can be equal to the resistance value of the fourth voltage divider resistor R4, or the resistance value of the third voltage divider resistor R3 can be different from the resistance value of the fourth voltage divider resistor R4. In this embodiment, there is no specific restriction on the ratio of the resistance values ​​of the third voltage divider resistor R3 and the fourth voltage divider resistor R4.

[0089] It should be noted that the resistance value of the fifth voltage divider resistor R5 can be equal to the resistance value of the sixth voltage divider resistor R6, or the resistance value of the fifth voltage divider resistor R5 can be different from the resistance value of the sixth voltage divider resistor R6. In this embodiment, there is no specific restriction on the ratio of the resistance values ​​of the fifth voltage divider resistor R5 and the sixth voltage divider resistor R6.

[0090] It should be noted that the resistance values ​​of the first sampling resistor SR1, the second sampling resistor SR2, and the third sampling resistor SR3 can be less than 10 ohms. This embodiment does not impose specific limitations on the resistance values ​​of the sampling circuit.

[0091] It should be noted that the resistance values ​​of the first voltage divider resistor R1, the second voltage divider resistor R2, the third voltage divider resistor R3, the fourth voltage divider resistor R4, the fifth voltage divider resistor R5, and the sixth voltage divider resistor R6 can all be greater than or equal to 1000 ohms. This embodiment does not specifically limit the resistance value of the sampling circuit.

[0092] The sampling circuit in this embodiment is applied to the three-phase motor M, and its working principle is as follows: The control module CM can set the control flow for the first N-type MOSFET Q1, the second N-type MOSFET Q2, the third N-type MOSFET Q3, the fourth N-type MOSFET Q4, the fifth N-type MOSFET Q5, and the sixth N-type MOSFET Q6 according to the operation requirements of the three-phase motor M.

[0093] For example, the control module CM can control the gate voltage of the six N-type MOSFETs (including the first N-type MOSFET Q1, the second N-type MOSFET Q2, the third N-type MOSFET Q3, the fourth N-type MOSFET Q4, the fifth N-type MOSFET Q5, and the sixth N-type MOSFET Q6) at the first moment, so that the first N-type MOSFET Q1, the fourth N-type MOSFET Q4, and the sixth N-type MOSFET Q6 are turned on, while the second N-type MOSFET Q2, the third N-type MOSFET Q3, and the fifth N-type MOSFET Q5 are turned off. At this time, the electrical signal generated by the input power supply P can be transmitted to the U terminal of the three-phase motor M through the first N-type MOSFET Q1, and then shunted inside the three-phase motor M, and output to the second sampling resistor SR2 and the third sampling resistor SR3 through the V terminal and W terminal of the three-phase motor M, respectively. Then, the electrical signal is boosted by the second bias unit and the third bias unit and output to the second sampling output terminal and the third sampling output terminal, so that the signal processing module 120 can sample the electrical signal through the second sampling output terminal and the third sampling output terminal.

[0094] The control module CM can control the gate voltage of the six N-type MOSFETs (including the first N-type MOSFET Q1, the second N-type MOSFET Q2, the third N-type MOSFET Q3, the fourth N-type MOSFET Q4, the fifth N-type MOSFET Q5, and the sixth N-type MOSFET Q6) at the second time, so that the second N-type MOSFET Q2, the third N-type MOSFET Q3, and the sixth N-type MOSFET Q6 are turned on, while the first N-type MOSFET Q1, the fourth N-type MOSFET Q4, and the fifth N-type MOSFET Q5 are turned off. At this time, the electrical signal generated by the input power supply P can be transmitted to the V terminal of the three-phase motor M through the third N-type MOSFET Q3. Then, it is shunted inside the three-phase motor M and output to the first sampling resistor SR1 and the third sampling resistor SR3 through the U terminal and W terminal of the three-phase motor M, respectively. Then, the electrical signal is boosted by the first bias unit and the third bias unit and output to the first sampling output terminal and the third sampling output terminal, so that the signal processing module 120 can sample the electrical signal through the first sampling output terminal and the third sampling output terminal.

[0095] The control module CM can control the gate voltage of the six N-type MOSFETs (including the first N-type MOSFET Q1, the second N-type MOSFET Q2, the third N-type MOSFET Q3, the fourth N-type MOSFET Q4, the fifth N-type MOSFET Q5, and the sixth N-type MOSFET Q6) at the third time, so that the second N-type MOSFET Q2, the fourth N-type MOSFET Q4, and the fifth N-type MOSFET Q5 are turned on, while the first N-type MOSFET Q1, the third N-type MOSFET Q3, and the sixth N-type MOSFET Q6 are turned off. At this time, the electrical signal generated by the input power supply P can be transmitted to the W terminal of the three-phase motor M through the fifth N-type MOSFET Q5. Then, it is shunted inside the three-phase motor M and output to the first sampling resistor SR1 and the second sampling resistor SR2 through the V terminal and the U terminal of the three-phase motor M, respectively. Then, the electrical signal is boosted by the first bias unit and the second bias unit and output to the first sampling output terminal and the second sampling output terminal, so that the signal processing module 120 can sample the electrical signal through the first sampling output terminal and the second sampling output terminal.

[0096] During operation, the control module CM can cyclically control the gate voltages of the six N-type MOSFETs (including the first N-type MOSFET Q1, the second N-type MOSFET Q2, the third N-type MOSFET Q3, the fourth N-type MOSFET Q4, the fifth N-type MOSFET Q5, and the sixth N-type MOSFET Q6) according to the above process. This allows the signal processing module 120 to acquire the sampling signal generated by the sampling module based on the electrical signals output from the U, V, and W terminals of the three-phase motor M. Then, the signal processing module 120 can input excitation current to the motor M based on the sampling signal. This allows it to compensate for the current value of the electrical signal output by the motor M without affecting the speed of the motor M, thereby adjusting the current value of the compensation sampling signal. This sampling circuit does not require Hall elements or operational amplifiers to accurately sample the electrical signal output by the motor M and can effectively reduce costs.

[0097] Based on the structure of the sampling circuit described above, various embodiments of the sampling method of the present invention are proposed.

[0098] In one embodiment, refer to Figure 4 , Figure 4 This is a flowchart of a sampling method provided in an embodiment of the present invention. The sampling method is applied to the signal processing module of an air conditioner. In one embodiment, the sampling method includes, but is not limited to, the following steps:

[0099] Step S410: Obtain the sampled signal from the output of the sampling module;

[0100] Step S420: Input excitation current to the motor according to the current value of the sampled signal to adjust the current value of the sampled signal.

[0101] The signal processing module in an air conditioner can acquire the sampled signal from the output of the sampling module. Then, based on the current value of the sampled signal, it inputs an excitation current to the motor to adjust the current value of the motor's output electrical signal. This, in turn, adjusts the current value of the sampled signal generated by the sampling circuit based on the electrical signal. This allows for accurate sampling of the motor's electrical signal while effectively reducing costs. For example, when the current value of the sampled signal is too low, the excitation current value can be increased and input to the motor to increase the current value of the sampled signal. Conversely, when the current value of the sampled signal is too high, the excitation current value can be decreased and input to the motor to decrease the current value of the sampled signal.

[0102] It should be noted that the signal processing module 120 can be set in the microcontroller unit or set independently; this embodiment does not specifically limit it.

[0103] Reference Figure 5 In one embodiment, step S420 includes, but is not limited to, the following steps:

[0104] Step S510: Determine the current value of the excitation current of the input motor based on the current value of the sampled signal;

[0105] Step S520: The excitation current is input to the motor to adjust the electrical signal output by the motor so that the current value of the sampling signal generated by the sampling circuit based on the electrical signal is greater than or equal to the first current threshold.

[0106] In one embodiment, the signal processing module can determine the excitation current value based on the current value of the acquired sampling current. Then, the signal processing module can output the determined excitation current to the motor to adjust the electrical signal output by the motor, so that the current value of the sampling signal generated by the sampling circuit based on the electrical signal is greater than or equal to a first current threshold. This enables accurate sampling of the motor's electrical signal while effectively reducing costs.

[0107] In one embodiment, both the sampling current and the motor's electrical signal can include armature current and excitation current. Normally, the excitation current is 0. If the sampling current value is less than a first current threshold, the armature current can be left unadjusted to avoid affecting the motor's speed. The signal processing module can adjust the excitation current and then input the excitation current to the motor to increase the current value of the motor's output electrical signal, so that the sampling current value is greater than or equal to the first current threshold, thereby further improving the sampling accuracy.

[0108] It should be noted that when the current value of the sampled current obtained by the signal processing module is greater than the first current threshold and less than the second current threshold, the current value of the armature current increases with the increase of the motor speed. The adjustment law of the excitation current value input by the signal processing module to the motor can be a law of decreasing with the increase of the motor speed. The current value of the excitation current input by the signal processing module to the motor can also be a fixed current value. This embodiment does not make specific limitations on it.

[0109] Reference Figure 6 In one embodiment, the steps following step S520 include, but are not limited to, the following steps:

[0110] Step S610: When the current value of the sampled signal is equal to the second current threshold, adjust the current value of the excitation current.

[0111] Step S620: The excitation current is input to the motor to adjust the electrical signal output by the motor so that the current value of the sampling signal generated by the sampling circuit based on the electrical signal is less than or equal to the second current threshold.

[0112] In one embodiment, when the current value of the sampled signal acquired by the signal processing module is equal to the second current threshold, for example, when the motor speed is increasing and the current value of the armature current output by the motor is also increasing, if the current value of the acquired sampled signal is equal to the second current threshold, the current value of the sampled signal will also become larger if the current value of the excitation current is not controlled, which is not conducive to sampling. Therefore, the signal processing module can adjust the current value of the excitation current to make the current value of the sampled signal less than or equal to the second current threshold, thereby achieving accurate sampling of the motor's electrical signal while effectively reducing costs.

[0113] In one embodiment, as the motor speed increases, the armature current value also increases. When the sampling current value is equal to the second current threshold, the signal processing module can reduce the excitation current input to the motor, thereby reducing the current value of the electrical signal output by the motor, so that the current value of the sampling signal is less than or equal to the second current threshold.

[0114] It should be noted that when the current value of the sampled current obtained by the signal processing module reaches the second current threshold, and the motor speed needs to continue to increase, the signal processing module can adjust the current value of the excitation current input to the motor to decrease. That is, in this case, the adjustment law of the excitation current value can be the law of decreasing as the motor speed increases, so as to adjust the current value of the sampled current to not exceed the second current threshold.

[0115] It should be noted that both the first current threshold and the second current threshold can be set according to the actual situation of the target motor M being sampled, and this embodiment does not impose any specific limitations on them.

[0116] It should be noted that the adjustment and change of the excitation current value can also be explained using a coordinate graph. For example, in a coordinate graph where the vertical axis is the current value and the horizontal axis is the motor speed, the armature current is a curve where the current value is directly proportional to the speed. The curve for adjusting the excitation current value can be a curve that gradually decreases to 0 from the first current value set when the motor M outputs its lowest speed (a curve where the current value is inversely proportional to the speed). Alternatively, it can be a curve composed of a first straight line and a second straight line. The first straight line is a straight line that starts from the second current value set when the motor M outputs its lowest speed and remains at the second current value until the sampled current reaches the second current threshold (i.e., the first straight line is a straight line parallel to the horizontal axis). The second straight line is a straight line that gradually decreases from the second current value to 0 when the sampled current reaches the second current threshold (i.e., the second straight line is a curve where the current value is inversely proportional to the speed). As long as the current value requirements for compensating the sampled current are met, this embodiment does not specifically limit the shape of the curve for adjusting the excitation current.

[0117] It should be noted that the excitation current adjustment curve can also be set in a quadrant where the current value is negative and the target speed value is positive. In this case, the excitation current adjustment curve can be a compensation curve that is mirror-symmetrical to the compensation curve set in a quadrant where both the current value and the target speed value are positive.

[0118] Another embodiment of the present invention also provides a circuit board, see reference Figure 7 The circuit board 720 includes the sampling circuit 710 described in the previous embodiment. The sampling circuit 710 may include one or more sampling modules connected in parallel and a signal processing module connected to the output of the sampling modules. The output of the signal processing module is connected to the motor. Each sampling module samples the electrical signal of one phase of the motor output, and each sampling module samples the electrical signal of a different phase. The signal processing module inputs an excitation current to the motor based on the sampled signal to adjust the current value of the sampled signal. The sampled signal is the signal output by the sampling module based on the electrical signal. By inputting an excitation current to the motor through the signal processing module, the current value of the electrical signal output by the motor can be compensated without affecting the motor speed, thereby adjusting the current value of the compensated sampled signal. This sampling circuit does not require Hall elements or operational amplifiers to accurately sample the electrical signal output by the motor and can effectively reduce costs.

[0119] Another embodiment of the present invention also provides a sampling device, referring to Figure 8The sampling device 810 includes the circuit board 720 of the aforementioned embodiment, and the circuit board 720 includes the sampling circuit 710 of the aforementioned embodiment. The sampling circuit 710 may include one or more sampling modules connected in parallel and a signal processing module connected to the output terminal of the sampling module. The output terminal of the signal processing module is connected to the motor. The sampling module is used to sample the electrical signal of one phase of the motor output, and each sampling module is used to sample the electrical signal of a different phase. The signal processing module is used to input an excitation current to the motor according to the sampling signal to adjust the current value of the sampling signal. The sampling signal is the signal output by the sampling module based on the electrical signal. By inputting an excitation current to the motor through the signal processing module, the current value of the electrical signal output by the motor can be compensated without affecting the motor speed, thereby adjusting the current value of the compensation sampling signal. This sampling circuit does not require the use of Hall elements or operational amplifiers to accurately sample the electrical signal output by the motor and can effectively reduce costs.

[0120] Another embodiment of the present invention also provides an air conditioner, see reference. Figure 9 The air conditioner 910 includes the sampling device 810 of the aforementioned embodiment, the sampling device 810 includes the circuit board 720 of the aforementioned embodiment, and the circuit board 720 includes the sampling circuit 710 of the aforementioned embodiment. The sampling circuit 710 may include one or more sampling modules connected in parallel and a signal processing module connected to the output terminal of the sampling module. The output terminal of the signal processing module is connected to the motor. The sampling module is used to sample the electrical signal of one phase of the motor output, and each sampling module is used to sample the electrical signal of a different phase. The signal processing module is used to input an excitation current to the motor according to the sampling signal to adjust the current value of the sampling signal. The sampling signal is the signal output by the sampling module according to the electrical signal. By inputting an excitation current to the motor through the signal processing module, the current value of the electrical signal output by the motor can be compensated without affecting the motor speed, thereby adjusting and compensating the current value of the sampling signal. This sampling circuit does not require the use of Hall elements or operational amplifiers to accurately sample the electrical signal output by the motor and can effectively reduce costs.

[0121] Another embodiment of the present invention also provides an air conditioner, see reference. Figure 10 The air conditioner 1000 includes a memory 1020, a processor 1010, and a computer program stored in the memory 1020 and executable on the processor 1010. When the computer program is executed by the processor 1010, it implements any of the aforementioned sampling methods. The signal processing module in the air conditioner can acquire the sampling signal from the output of the sampling module, and then input an excitation current to the motor according to the current value of the sampling signal to adjust the current value of the electrical signal output by the motor. This adjusts the current value of the sampling signal generated by the sampling circuit based on the electrical signal, enabling accurate sampling of the motor's electrical signal while effectively reducing costs.

[0122] Another embodiment of the present invention provides a computer-readable storage medium storing computer-executable instructions that are executed by a processor or controller, for example, by a processor in an air conditioner as described above, causing the processor to perform the flow management method described above, for example, performing the above-described... Figure 4 Method steps S410 to S420 in the text Figure 5 Method steps S510 to S520 in the text Figure 6 Method steps S610 to S620.

[0123] It will be understood by those skilled in the art that all or some of the steps and systems in the methods disclosed above can be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components can be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, as is known to those skilled in the art, communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0124] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the above embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of the present invention.

Claims

1. A sampling circuit applied to the motor of an air conditioner, characterized in that, The sampling circuit includes: One or more sampling modules are connected in parallel, wherein the sampling module is used to sample the electrical signal of one phase of the motor output, and each sampling module is used to sample the electrical signal of a different phase; The signal processing module has its input terminal connected to the output terminal of the sampling module and its output terminal connected to the motor. The signal processing module is used to input an excitation current to the motor according to the sampling signal in order to adjust the current value of the sampling signal. The sampling signal is the signal output by the sampling module according to the sampled electrical signal. When the current value of the sampled signal is less than the first current threshold, the signal processing module adjusts the excitation current and inputs the adjusted excitation current to the motor to increase the current value of the electrical signal output by the motor, so that the current value of the sampled signal is greater than or equal to the first current threshold.

2. The sampling circuit according to claim 1, characterized in that, The sampling module includes a switch group, a sampling unit connected to the switch group, and a biasing unit for biasing the electrical signal. One end of the biasing unit is connected to the connection terminal of the sampling unit and the switch group, and the other end is connected to the input terminal of the signal processing module.

3. The sampling circuit according to claim 2, characterized in that, The bias unit includes a bias power supply, a first voltage divider resistor, and a second voltage divider resistor. One end of the first voltage divider resistor is connected to the bias power supply, and the other end is connected to one end of the second voltage divider resistor. The other end of the second voltage divider resistor is connected to the connection terminal of the switch group and the sampling unit. The connection terminal between the first voltage divider resistor and the second voltage divider resistor is connected to the input terminal of the signal processing module.

4. The sampling circuit according to claim 2, characterized in that, The switch assembly includes a first switch component and a second switch component connected in series with the first switch component. The connection ends of the first switch component and the second switch component are connected to the input end of the motor.

5. The sampling circuit according to claim 3, characterized in that, The resistance value of the first voltage divider resistor is equal to the resistance value of the second voltage divider resistor.

6. The sampling circuit according to claim 3, characterized in that, The sampling unit includes a sampling resistor, the resistance value of which is smaller than that of the first voltage divider resistor and the resistance value of which is smaller than that of the second voltage divider resistor.

7. The sampling circuit according to claim 6, characterized in that, The resistance value of the sampling resistor is less than or equal to 10 ohms, the resistance value of the first voltage divider resistor is greater than or equal to 1000 ohms, and the resistance value of the second voltage divider resistor is greater than or equal to 1000 ohms.

8. A sampling method applied to a signal processing module of a sampling circuit, characterized in that, The sampling circuit further includes one or more sampling modules connected in parallel. The sampling modules are used to sample the electrical signal of one phase of the motor output, and each sampling module is used to sample the electrical signal of a different phase. The input terminal of the signal processing module is connected to the output terminal of the sampling module, and the output terminal of the signal processing module is connected to the motor. The method includes: Acquire the sampled signal from the output of the sampling module; The excitation current is input to the motor according to the current value of the sampled signal, so as to adjust the current value of the sampled signal; The step of inputting excitation current to the motor based on the current value of the sampled signal to adjust the current value of the sampled signal includes: If the current value of the sampled signal is less than the first current threshold, the current value of the excitation current input to the motor is determined based on the current value of the sampled signal. The excitation current is input to the motor to adjust the electrical signal output by the motor, so that the current value of the sampling signal generated by the sampling circuit based on the electrical signal is greater than or equal to a first current threshold.

9. The sampling method according to claim 8, characterized in that, Also includes: When the current value of the sampled signal is equal to the second current threshold, the current value of the excitation current is adjusted; The excitation current is input to the motor to adjust the electrical signal output by the motor, so that the current value of the sampling signal generated by the sampling circuit based on the electrical signal is less than or equal to the second current threshold.

10. A circuit board, characterized in that, Includes the sampling circuit described in any one of claims 1 to 7.

11. A sampling device, characterized in that, It includes the sampling circuit according to any one of claims 1 to 7, or the circuit board according to claim 10.

12. An air conditioner, characterized in that, It includes the sampling circuit according to any one of claims 1 to 7, or the circuit board according to claim 10, or the sampling device according to claim 11.

13. An air conditioner, characterized in that, A memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor, when executing the computer program, implements the sampling method according to any one of claims 8 to 9.

14. A computer-readable storage medium storing computer-executable instructions for performing the sampling method according to any one of claims 8 to 9.

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