Signal sampling circuit, controller, outdoor unit and air conditioner

Abstract

The utility model discloses a signal sampling circuit, comprising a differential sampling port used for obtaining a first analog differential signal relative to a first reference ground from a sampled object; the signal isolation module is connected with the differential sampling port and used for converting the first analog differential signal into a second analog differential signal relative to a second reference ground, and the first reference ground is different from the second reference ground; and the differential output port is connected with the signal isolation module and is used for outputting a second analog differential signal. According to the utility model, the signal isolation module is arranged in the signal sampling circuit, so that the driving control of the controller shared by two or more fan driving modules which are not in common ground can be realized, and the signal isolation module prevents signal sampling errors caused by voltage differences among different grounding reference points, thereby improving the accuracy of electric signal sampling.

Description

Technical Field

[0001] The utility model relates to the technical field of air conditioners, and in particular to a signal sampling circuit, a controller, an outdoor unit and an air conditioner. Background Art

[0002] The control circuit for dual DC fans in an air conditioning system includes dual fan inverter drive modules. Typically, the dual fan inverter drive modules share a common bus, or the dual fan inverter drive modules share a common bus with the compressor inverter drive module. When the fan inverter drive modules share a common bus and a common ground, the dual fan inverter drive modules can be controlled simultaneously by a single controller, and the voltage signals of the dual fan inverter drive modules can be sampled by sampling the bus voltage signals. However, when the dual fan inverter drive modules in the air conditioning system's control circuit do not share a common bus or ground, such as when the first fan inverter drive module draws power from the upper half of the bus and the second fan inverter drive module draws power from the lower half of the bus, the controller cannot simultaneously transmit drive signals and feedback signals to the first and second fan inverter drive modules. If the same controller is still used to simultaneously control the first and second fan inverter drive modules, the accuracy of the bus voltage divider signal sampling of the dual fan inverter drive modules will be affected, thereby affecting the accuracy of the controller's feedback signals. Utility Model Content

[0003] The purpose of the present utility model is to solve at least one of the technical problems existing in the prior art and to provide a signal sampling circuit, a controller, an outdoor unit and an air conditioner, which are conducive to realizing the drive control of two or more fan drive modules with different grounding and a common controller, while improving the accuracy of electrical signal sampling.

[0004] In a first aspect, an embodiment of the present invention provides a signal sampling circuit, comprising:

[0005] A differential sampling port, configured to obtain a first analog differential signal relative to a first reference ground from a sampled object;

[0006] a signal isolation module connected to the differential sampling port, configured to convert the first analog differential signal into a second analog differential signal relative to a second reference ground, wherein the first reference ground is different from the second reference ground;

[0007] The differential output port is connected to the signal isolation module and is used to output the second analog differential signal.

[0008] According to some embodiments of the present invention, the sampled object includes one of the following:

[0009] Connect the power bus of the fan IPM module;

[0010] Connect the power bus of the compressor IPM module;

[0011] Connect the current sampling resistor of the power bus;

[0012] Temperature sampling resistor used to measure the temperature of power devices.

[0013] According to some embodiments of the present invention, the signal sampling circuit further includes a single-ended signal output port and a signal conversion module, wherein the signal conversion module is connected between the differential output port and the single-ended signal output port, and is used to convert the second analog differential signal into a single-ended analog sampling signal, and output the single-ended analog sampling signal through the single-ended signal output port.

[0014] According to some embodiments of the present invention, the differential output port includes a first differential port and a second differential port, the signal conversion module includes a positive input terminal, a negative input terminal, and an output terminal, the positive input terminal is connected to the first differential port, the negative input terminal is connected to the second differential port, and the output terminal is connected to the single-ended signal output port;

[0015] The signal conversion module further includes a first capacitor, a first resistor and a bias resistor. The first capacitor and the first resistor are connected in parallel between the negative input terminal and the output terminal. The positive input terminal is connected to the second reference ground through the bias resistor.

[0016] According to some embodiments of the present invention, the signal sampling circuit further includes a current limiting resistor and a filter capacitor, the current limiting resistor is connected in series between the output end and the single-ended signal output port, and the filter capacitor is connected between the single-ended signal output port and the second reference ground.

[0017] According to some embodiments of the present invention, the signal sampling circuit also includes a first signal balancing module, the signal isolation module includes a differential signal input port, and the first signal balancing module is connected between the differential sampling port and the differential signal input port, and is used to perform signal balancing on the first analog differential signal.

[0018] According to some embodiments of the present invention, the differential sampling port includes a first differential sampling port and a second differential sampling port, the differential signal input port includes a first differential input port and a second differential input port, and the first signal balancing module includes a first balancing resistor, a second balancing resistor, and a first balancing capacitor, the first balancing resistor being connected between the first differential sampling port and the first differential input port, the second balancing resistor being connected between the second differential sampling port and the second differential input port, and the first balancing capacitor being connected between the first differential input port and the second differential input port.

[0019] According to some embodiments of the present invention, the signal sampling circuit further includes a second signal balancing module, the signal isolation module includes a differential signal output port, and the second signal balancing module is connected between the differential signal output port and the differential output port, and is used to perform signal balancing on the second analog differential signal.

[0020] According to some embodiments of the present invention, the differential output port includes a first differential port and a second differential port, the differential signal output port includes a first differential output port and a second differential output port, the second signal balancing module includes a third balancing resistor, a fourth balancing resistor and a second balancing capacitor, the third balancing resistor is connected between the first differential port and the first differential output port, the fourth balancing resistor is connected between the second differential port and the second differential output port, and the second balancing capacitor is connected between the first differential port and the second differential port.

[0021] In a second aspect, an embodiment of the present invention provides a controller, comprising the signal sampling circuit described in the technical solution of the first aspect.

[0022] In a third aspect, an embodiment of the present invention provides an outdoor unit, comprising the controller described in the technical solution of the second aspect above.

[0023] In a fourth aspect, an embodiment of the present invention provides an air conditioner, comprising the signal sampling circuit described in the technical solution of the first aspect, or the controller described in the technical solution of the second aspect, or the outdoor unit described in the technical solution of the third aspect.

[0024] The signal sampling circuit, controller, outdoor unit and air conditioner provided by the embodiments of the present invention have at least the following beneficial effects: by arranging a signal isolation module in the signal sampling circuit to convert the first analog differential signal into a second analog differential signal relative to the second reference ground, the signal sampling circuit can collect the current or voltage signal of the dual-fan inverter drive module that does not share a bus or a common ground, and the controller can issue a drive signal based on the second analog differential signal to simultaneously control the dual-fan inverter drive modules that do not share a bus or a common ground, thereby realizing the drive control of two or more fan drive modules that do not share a common ground and share a common controller; the signal isolation module can protect the drive signal and the feedback signal from the influence of voltage fluctuations or noise between different reference grounds, thereby realizing electrical isolation of the signal, improving the accuracy of electrical signal sampling, and at the same time improving the precision of the controller feedback signal.

[0025] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or understood by practicing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings are used to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the technical solution of the present invention and do not constitute a limitation on the technical solution of the present invention.

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments;

[0028] Figure 1 This is a topological structure diagram of an air-conditioning system control circuit with dual fan inverter drive modules sharing a common busbar, provided by an embodiment of the present utility model;

[0029] Figure 2 This is a topological diagram of another air-conditioning system control circuit with dual fan inverter drive modules sharing a busbar, provided by an embodiment of the present utility model;

[0030] Figure 3 This is a signal transmission diagram between a controller and a dual-fan inverter drive module when dual-fan modules share a common bus and a common ground, provided by an embodiment of the present utility model;

[0031] Figure 4 This is a topological structure diagram of an air-conditioning system control circuit with dual fan inverter drive modules and no shared bus provided by an embodiment of the utility model;

[0032] Figure 5 This is a circuit diagram of a signal sampling circuit provided by an embodiment of the utility model. DETAILED DESCRIPTION

[0033] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0034] In the description of this utility model, "several" means one or more, "more" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, and "above," "below," and "within" are understood to include the number itself. "Any one" means one or more, and "at least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and is not to be construed as indicating or implying relative importance, or implicitly indicating the number of the indicated technical features, or implicitly indicating the order of the indicated technical features.

[0035] It should be noted that the terms "set," "install," and "connect" in the embodiments of the present invention should be interpreted broadly. Those skilled in the art can reasonably determine the specific meanings of these terms in the embodiments of the present invention based on the specific content of the technical solution. For example, the term "connect" can refer to mechanical connection, electrical connection, or communication; it can refer to direct connection or indirect connection through an intermediary.

[0036] It should be noted that the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0037] The control circuit of the dual DC fan of the air conditioning system includes a dual fan inverter drive module. The drive scheme of the dual fan inverter drive module usually includes the following two schemes. The first scheme is as follows: Figure 1 As shown, the dual-fan inverter drive module includes a first fan IPM module and a second fan IPM module. The first fan IPM module and the second fan IPM module share a bus bar, and the first fan IPM module and the second fan IPM module are powered by single-phase rectification separately. The second solution is as follows: Figure 2 As shown, the dual-fan inverter drive module includes a first fan IPM module and a second fan IPM module, and the first fan IPM module and the second fan IPM module share a bus with the compressor IPM module. In the first and second schemes above, the dual-fan modules share a bus and a common GND, so the dual-fan inverter drive modules can be controlled simultaneously by the same controller, and the bus voltage signal of the dual-fan inverter drive modules can be sampled. It can be understood that when the dual-fan modules share a bus and a common GND, the drive and feedback signals between the controller and the dual-fan inverter drive module can be transmitted, refer to Figure 3 As shown, Figure 3 This is a signal transmission diagram between the controller and the dual-fan inverter drive module when the dual-fan modules share a common bus and ground. In the figure, MCU is the controller and IPM is the dual-fan inverter drive module. The current sampling signal, temperature sampling signal and F0 signal of the dual-fan inverter drive module can be directly transmitted to the controller.

[0038] However, when the dual fan inverter drive modules in the control circuit of the air conditioning system do not share a common bus or ground, such as Figure 4 As shown, the two DC fan IPM modules of the dual-fan inverter drive module draw power from the upper and lower busbars, respectively. For example, the first fan IPM module draws power from the upper busbar, and the second fan IPM module draws power from the lower busbar. Because the first and second fan IPM modules do not share a busbar, the controller cannot simultaneously transmit drive and feedback signals to the first and second fan IPM modules. If the same controller is used to control the first and second fan IPM modules simultaneously, the accuracy of the voltage signal sampling of the first and second fan IPM modules will be affected, thereby affecting the accuracy of the controller's feedback signal.

[0039] Based on this, the embodiment of the present invention provides a signal sampling circuit, a controller, an outdoor unit and an air conditioner, which are conducive to realizing the drive control of two or more fan drive modules with different grounding and a common controller, while improving the accuracy of electrical signal sampling.

[0040] When the dual-fan inverter drive modules in the control circuit of the air-conditioning system do not share a common bus or a common ground, the drive signal and feedback signal of the fan inverter module powered by the upper half bus need to be isolated from the controller. Therefore, the signal sampling circuit of the embodiment of the utility model adds a signal isolation module between the controller and the dual-fan inverter drive module. The signal isolation module can prevent signal sampling errors caused by the voltage difference between different ground reference points. The signal isolation module can reduce noise and interference in the transmission process of the drive signal and feedback signal, thereby improving the signal quality and the reliability of the signal sampling circuit.

[0041] Reference Figure 5 As shown, Figure 5 This is a circuit diagram of a signal sampling circuit provided by an embodiment of the present invention. The signal sampling circuit includes a differential sampling port, a signal isolation module and a differential output port. The differential sampling port is used to obtain a first analog differential signal relative to a first reference ground from a sampled object; the signal isolation module is connected to the differential sampling port and is used to convert the first analog differential signal into a second analog differential signal relative to a second reference ground, wherein the first reference ground and the second reference ground are different; the differential output port is connected to the signal isolation module and is used to output the second analog differential signal.

[0042] The differential sampling port is the input part of the signal sampling circuit. The differential sampling port is used to obtain a first analog differential signal relative to a first reference ground from a sampled object (such as a sensor, amplifier, etc.). A differential signal refers to two signals of equal amplitude and opposite phases. The differential signal can effectively suppress common mode noise. A signal isolation module is provided to be connected to the differential sampling port. The signal isolation module converts the first analog differential signal obtained by the differential sampling port into a second analog differential signal relative to a second reference ground. It should be noted that the first reference ground is different from the second reference ground. The signal isolation module can protect the drive signal and the feedback signal from the influence of voltage fluctuations or noise between different reference grounds. At the same time, it can also realize electrical isolation of the signal, thereby improving the stability and safety of the signal sampling circuit. The differential output port is connected to the signal isolation module to output a second analog differential signal that has been subjected to differential signal conversion processing by the signal isolation module. The second analog differential signal is input to the signal receiving port of the controller, so that the controller outputs a corresponding drive signal according to the second analog differential signal.

[0043] By setting a signal isolation module in the signal sampling circuit to convert the first analog differential signal into a second analog differential signal relative to the second reference ground, the signal sampling circuit can collect the current or voltage signal of the dual wind turbine inverter drive module that does not share a bus or a common ground. The controller can issue a drive signal according to the second analog differential signal to simultaneously control the dual wind turbine inverter drive modules that do not share a bus or a common ground, thereby realizing the drive control of two or more wind turbine drive modules that do not share a common ground and share a common controller; the signal isolation module can protect the drive signal and the feedback signal from the influence of voltage fluctuations or noise between different reference grounds, thereby realizing electrical isolation of the signal, improving the accuracy of electrical signal sampling, and at the same time improving the accuracy of the controller feedback signal.

[0044] In some embodiments of the present invention, a signal sampling circuit can obtain a first analog differential signal relative to a first reference ground from a sampled object via a differential sampling port. The first analog differential signal includes, but is not limited to, a bus voltage divided sampling signal of a dual-fan drive module, a current sampling signal flowing through a resistor, or a temperature signal output by a power module, a FO signal, and a PWM signal. Embodiments of the present invention do not limit the type of the first analog differential signal relative to the first reference ground obtained from the sampled object. The signal sampling circuit obtains the bus voltage divided sampling signal of the dual-fan drive module, the current sampling signal flowing through a resistor, or the temperature signal output by the power module, a FO signal, and a PWM signal relative to the first reference ground from the sampled object via the differential sampling port. The isolation module converts the above signals into a second analog differential signal relative to a second reference ground. The second analog differential signal is transmitted to a controller via a differential output port. The controller can issue a drive signal based on the second analog differential signal to simultaneously control dual-fan inverter drive modules that do not share a common bus or ground, thereby achieving drive control of two or more fan drive modules that do not share a common ground and share a common controller.

[0045] It's understood that the first and second reference grounds are two different ground potential points within the signal sampling circuit. In practical applications, these first and second reference grounds may differ depending on the power supply system, signal source, or device. For example, the first reference ground is typically connected to the ground of the signal source or sensor, while the second reference ground is connected to the ground of the receiving device or controller.

[0046] In some embodiments of the present invention, the sampled object includes one of the following: a power bus connected to a wind turbine IPM module;

[0047] Connect the power bus of the compressor IPM module; connect the current sampling resistor of the power bus; and use the temperature sampling resistor to measure the temperature of the power device.

[0048] In the control circuit of the air-conditioning system, sampling of the power bus, current sampling resistors, and temperature sampling resistors is crucial. In the signal sampling circuit, the sampling differential sampling port is used to obtain a first analog differential signal relative to a first reference ground from the sampled object; the advantage of the differential signal is that it can resist common-mode noise and provide clearer signal transmission, thereby improving the reliability and performance of the signal sampling circuit. It is understood that the sampled objects include but are not limited to the power bus connected to the fan IPM module, the power bus connected to the compressor IPM module, the current sampling resistor connected to the power bus, and the temperature sampling resistor used to measure the temperature of the power device.

[0049] The differential sampling port can be used to monitor the power bus voltage of the fan IPM module, ensuring the stability of the power supply of the signal sampling circuit and timely detecting any abnormal fluctuations; the differential sampling port helps monitor the power bus of the compressor IPM module, which is critical for maintaining the efficient operation of the compressor. Through the differential sampling port, a differential signal can be obtained from the current sampling resistor. The differential signal obtained by the current sampling resistor represents the current flowing through the power bus, which is necessary for current detection and overcurrent protection mechanisms. The differential sampling port can also be used to monitor the temperature sampling resistor associated with the power device. By monitoring the temperature sampling resistor associated with the power device, the signal sampling circuit can monitor the temperature of the power device in real time and trigger the protection mechanism when an overheating condition is detected.

[0050] In some embodiments of the present invention, the signal sampling circuit further includes a single-ended signal output port Vout and a signal conversion module, the signal conversion module being connected between the differential output port and the single-ended signal output port Vout, for converting the second analog differential signal into a single-ended analog sampling signal, and outputting the single-ended analog sampling signal through the single-ended signal output port Vout.

[0051] The signal sampling circuit includes a differential sampling port for acquiring a first analog differential signal relative to a first reference ground from a sampled object; a signal isolation module connected to the differential sampling port for converting the first analog differential signal into a second analog differential signal relative to a second reference ground, wherein the first reference ground and the second reference ground are different; and a differential output port connected to the signal isolation module for outputting the second analog differential signal. The signal sampling circuit also includes a single-ended signal output port Vout and a signal conversion module. The single-ended signal output port Vout and the signal conversion module are connected between the differential output port and the single-ended signal output port Vout. The second analog differential signal outputted from the differential output port is transmitted to the signal conversion module. The signal conversion module converts the second analog differential signal into a single-ended analog sampling signal and outputs the single-ended analog sampling signal through the single-ended signal output port Vout.

[0052] By providing a signal conversion module and a single-ended signal output port Vout in the signal sampling circuit, the signal conversion module can convert the second analog differential signal into a single-ended analog sampling signal, processing the two differential signals output from the differential output port and outputting a single-ended analog sampling signal. The single-ended analog sampling signal is then output to the signal receiving port of the controller, so that the controller outputs a corresponding drive signal according to the single-ended analog sampling signal. The controller can issue a drive signal based on the single-ended analog sampling signal to simultaneously control dual wind turbine inverter drive modules that do not share a common bus or ground, thereby achieving drive control of two or more wind turbine drive modules that do not share a common ground and share a common controller; the signal isolation module can protect the drive signal and feedback signal from the influence of voltage fluctuations or noise between different reference grounds, thereby achieving electrical isolation of the signal, improving the accuracy of electrical signal sampling, and at the same time improving the precision of the controller feedback signal.

[0053] In some embodiments of the present invention, the differential output port includes a first differential port c and a second differential port d, and the signal conversion module includes a positive input terminal, a negative input terminal and an output terminal, the positive input terminal is connected to the first differential port c, the negative input terminal is connected to the second differential port d, and the output terminal is connected to the single-ended signal output port Vout; wherein, the signal conversion module also includes a first capacitor 221, a first resistor 102 and a bias resistor 103, the first capacitor 221 and the first resistor 102 are connected in parallel between the negative input terminal and the output terminal, and the positive input terminal is connected to the second reference ground through the bias resistor 103.

[0054] A differential signal is two signals of equal amplitude but opposite phases. Therefore, a differential output port is provided, including a first differential port c and a second differential port d. The first differential port c and the second differential port d provide the positive and negative phase signals of the differential signal, respectively. The signal conversion module includes a positive input, a negative input, and an output. It can be understood that the positive input is the positive input of the operational amplifier, the negative input is the negative input of the operational amplifier, and the output is the output of the operational amplifier. The positive input is connected to the first differential port c, the negative input is connected to the second differential port d, and the output is connected to the single-ended signal output port Vout. The positive input is connected to the first differential port c to receive the positive phase portion of the differential signal, the negative input is connected to the second differential port d to receive the negative phase portion of the differential signal, and the output is connected to the single-ended signal output port Vout to output the converted single-ended analog sampling signal. The signal conversion module also includes a first capacitor 221, a first resistor 102 and a bias resistor 103. The first capacitor 221 and the first resistor 102 are connected in parallel between the negative input terminal and the output terminal, and the positive input terminal is connected to the second reference ground through the bias resistor 103. The first capacitor 221 and the first resistor 102 are connected in parallel between the negative input terminal and the output terminal to build a high-pass filter to eliminate DC offset and suppress low-frequency noise. The first resistor 102 is the negative feedback resistor of the operational amplifier circuit. The parallel connection of the first capacitor 221 can prevent signal oscillation and improve the stability of the circuit operation. The positive input terminal is connected to the second reference ground through the bias resistor 103. The bias resistor 103 is used to set the DC level of the input terminal to ensure that the signal conversion module can correctly process the input differential signal.

[0055] In some embodiments of the present invention, the signal sampling circuit further includes a current limiting resistor 400 and a filter capacitor 410. The current limiting resistor 400 is connected in series between the output end and the single-ended signal output port Vout, and the filter capacitor 410 is connected between the single-ended signal output port Vout and the second reference ground.

[0056] In the signal sampling circuit, the current-limiting resistor 400 and the filter capacitor 410 are two very important components that play a protective and signal conditioning role in the circuit. The current-limiting resistor 400 is connected in series between the output terminal and the single-ended signal output port Vout. The current-limiting resistor 400 is used to limit the current passing through the signal sampling circuit to protect sensitive components in the signal sampling circuit, such as the input terminal of the operational amplifier or other signal processing components. The filter capacitor 410 is connected between the single-ended signal output port Vout and the second reference ground. The filter capacitor 410 is used to filter out high-frequency noise and smooth the output signal to obtain a clearer signal waveform.

[0057] It should be noted that the selection of the capacitance value of the filter capacitor 410 depends on the noise frequency that needs to be filtered and the operating frequency of the circuit. Generally, the larger the capacitance value, the better the filtering effect, but too large a capacitance may introduce a phase delay. The ESR (equivalent series resistance) and ESL (equivalent series inductance) of the filter capacitor 410 also affect the filtering effect, and a filter capacitor 410 with low ESR / ESL should be selected to obtain better performance. The withstand voltage value of the filter capacitor 410 should be higher than the maximum operating voltage of the circuit to avoid capacitor breakdown. In the signal sampling circuit, the combination of the current limiting resistor 400 and the filter capacitor 410 can effectively protect the signal sampling circuit and improve signal quality.

[0058] In some embodiments of the present invention, the signal sampling circuit also includes a first signal balancing module, the signal isolation module includes a differential signal input port, and the first signal balancing module is connected between the differential sampling port and the differential signal input port, and is used to perform signal balancing on the first analog differential signal.

[0059] In the signal sampling circuit, the first signal balancing module balances the first analog differential signal to ensure its stability and accuracy. It can be understood that the first signal balancing module can amplify the voltage difference between the two input terminals of the differential sampling port while suppressing the common voltage between the two input terminals of the differential sampling port and ground. The differential signal input port is the input terminal of the signal isolation module. The differential signal input port receives the differential signal from the signal source. The first signal balancing module is connected between the differential sampling port and the differential signal input port to ensure that the electrical signal does not introduce errors or interference due to imbalance during transmission.

[0060] In some embodiments of the present invention, the differential sampling port includes a first differential sampling port a and a second differential sampling port b, the differential signal input port includes a first differential input port 2 and a second differential input port 3, and the first signal balancing module includes a first balancing resistor 100, a second balancing resistor 110, and a first balancing capacitor 101. The first balancing resistor 100 is connected between the first differential sampling port a and the first differential input port 2, the second balancing resistor 110 is connected between the second differential sampling port b and the second differential input port 3, and the first balancing capacitor 101 is connected between the first differential input port 2 and the second differential input port 3.

[0061] The first signal balancing module in the signal sampling circuit is a differential signal balancing network, which is composed of a first balancing resistor 100, a second balancing resistor 110 and a first balancing capacitor 101. The differential signal balancing network helps to reduce the imbalance in the differential signal, thereby improving the quality of the electrical signal and the anti-interference capability of the signal sampling circuit.

[0062] The first differential sampling port a and the second differential sampling port b are used to obtain differential signals from the sampled object. For example, the first differential sampling port a and the second differential sampling port b can be connected to a power bus, a current sampling resistor, or a temperature sampling resistor. The first differential input port 2 and the second differential input port 3 are the inputs of the signal isolation module, receiving differential signals from the first differential sampling port a and the second differential sampling port b. The first balancing resistor 100 is connected to the first differential sampling port a and the first differential input port 2 to balance the two branches of the differential signal. The second balancing resistor 110 is connected to the second differential sampling port b and the second differential input port 3 and works in conjunction with the first balancing resistor 100 to balance the differential signal. It should be noted that the value of the second balancing resistor 110 should be equal to that of the first balancing resistor 100 to ensure balance between the two branches. The first balancing capacitor 101 is connected to the first differential input port 2 and the second differential input port 3 to isolate common-mode signals while allowing differential-mode signals to pass. The first signal balancing module helps improve the anti-interference capability of the sampled signal and ensure the stability and accuracy of the sampled signal during transmission.

[0063] In some embodiments of the present invention, the signal sampling circuit also includes a second signal balancing module, the signal isolation module includes a differential signal output port, and the second signal balancing module is connected between the differential signal output port and the differential output port, and is used to perform signal balancing on the second analog differential signal.

[0064] The second signal balancing module is used to balance the second analog differential signal output from the signal isolation module. The differential signal output port is the output portion of the signal isolation module and provides the isolated differential signal. The second signal balancing module connects the differential signal output port and the differential output port and is used to further balance the second analog differential signal. The differential output port is the output of the second signal balancing module, which outputs the balanced differential signal to subsequent circuits or systems, such as a controller. The second signal balancing module ensures the stability and accuracy of the second analog differential signal before further processing or transmission.

[0065] In some embodiments of the present invention, the differential output port includes a first differential port c and a second differential port d, the differential signal output port includes a first differential output port 7 and a second differential output port 6, the second signal balancing module includes a third balancing resistor 130, a fourth balancing resistor 140 and a second balancing capacitor 300, the third balancing resistor 130 is connected between the first differential port c and the first differential output port 7, the fourth balancing resistor 140 is connected between the second differential port d and the second differential output port 6, and the second balancing capacitor 300 is connected between the first differential port c and the second differential port d.

[0066] The second signal balancing module includes a third balancing resistor 130, a fourth balancing resistor 140, and a second balancing capacitor 300. These components work together to balance and filter the differential signal. The first differential port c is used to output the positive phase portion of the differential signal; the second differential port d is used to output the negative phase portion of the differential signal. The first differential output port 7 receives the positive phase differential signal from the second signal balancing module. The second differential output port 6 receives the negative phase differential signal from the second signal balancing module. The third balancing resistor 130 connects the first differential port c and the first differential output port 7 to balance the resistance value between the two ports, ensuring the differential characteristics of the signal.

[0067] The fourth balancing resistor 140 is connected to the second differential port d and the second differential output port 6, and is used in conjunction with the third balancing resistor 130 to maintain the balance of the signal. The second balancing capacitor 300 is connected to the first differential port c and the second differential port d, and is used to provide a path for high-frequency signals while blocking low-frequency signals to achieve the balance of differential signals. The values ​​of the third balancing resistor 130 and the fourth balancing resistor 140 should be equal to ensure that the two branches of the differential signal have the same impedance, thereby reducing signal distortion. The value of the second balancing capacitor 300 should be selected according to the frequency range that needs to be isolated. A larger capacitance value can provide better high-frequency signal isolation, but may introduce phase delay. The second signal balancing module can ensure the balance and filtering of the differential signal to improve the quality of the electrical signal and the anti-interference ability of the signal sampling circuit.

[0068] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in the technical field without departing from the purpose of the present invention.

Claims

1. A signal sampling circuit, characterized in that: include: A differential sampling port, configured to obtain a first analog differential signal relative to a first reference ground from a sampled object; a signal isolation module connected to the differential sampling port, configured to convert the first analog differential signal into a second analog differential signal relative to a second reference ground, wherein the first reference ground is different from the second reference ground; The differential output port is connected to the signal isolation module and is used to output the second analog differential signal.

2. The signal sampling circuit according to claim 1, wherein: The sampled object includes one of the following: Connect the power bus of the fan IPM module; Connect the power bus of the compressor IPM module; Connect the current sampling resistor of the power bus; Temperature sampling resistor used to measure the temperature of power devices.

3. The signal sampling circuit according to claim 1, wherein: The signal sampling circuit also includes a single-ended signal output port and a signal conversion module. The signal conversion module is connected between the differential output port and the single-ended signal output port, and is used to convert the second analog differential signal into a single-ended analog sampling signal, and output the single-ended analog sampling signal through the single-ended signal output port.

4. The signal sampling circuit according to claim 3, characterized in that: The differential output port includes a first differential port and a second differential port, the signal conversion module includes a positive input terminal, a negative input terminal and an output terminal, the positive input terminal is connected to the first differential port, the negative input terminal is connected to the second differential port, and the output terminal is connected to the single-ended signal output port; The signal conversion module further includes a first capacitor, a first resistor and a bias resistor. The first capacitor and the first resistor are connected in parallel between the negative input terminal and the output terminal. The positive input terminal is connected to the second reference ground through the bias resistor.

5. The signal sampling circuit according to claim 4, characterized in that: The signal sampling circuit further includes a current limiting resistor and a filter capacitor. The current limiting resistor is connected in series between the output end and the single-ended signal output port. The filter capacitor is connected between the single-ended signal output port and the second reference ground.

6. The signal sampling circuit according to claim 1, characterized in that: The signal sampling circuit further includes a first signal balancing module. The signal isolation module includes a differential signal input port. The first signal balancing module is connected between the differential sampling port and the differential signal input port and is used to perform signal balancing on the first analog differential signal.

7. The signal sampling circuit according to claim 6, characterized in that: The differential sampling port includes a first differential sampling port and a second differential sampling port, the differential signal input port includes a first differential input port and a second differential input port, the first signal balancing module includes a first balancing resistor, a second balancing resistor and a first balancing capacitor, the first balancing resistor is connected between the first differential sampling port and the first differential input port, the second balancing resistor is connected between the second differential sampling port and the second differential input port, and the first balancing capacitor is connected between the first differential input port and the second differential input port.

8. The signal sampling circuit according to claim 1, wherein: The signal sampling circuit further includes a second signal balancing module. The signal isolation module includes a differential signal output port. The second signal balancing module is connected between the differential signal output port and the differential output port and is used to perform signal balancing on the second analog differential signal.

9. The signal sampling circuit according to claim 8, characterized in that: The differential output port includes a first differential port and a second differential port, the differential signal output port includes a first differential output port and a second differential output port, the second signal balancing module includes a third balancing resistor, a fourth balancing resistor, and a second balancing capacitor, the third balancing resistor is connected between the first differential port and the first differential output port, the fourth balancing resistor is connected between the second differential port and the second differential output port, and the second balancing capacitor is connected between the first differential port and the second differential port.

10. A controller, characterized in that: The signal sampling circuit comprises the signal sampling circuit according to any one of claims 1 to 9.

11. An outdoor unit, characterized in that: The method comprises the signal sampling circuit according to any one of claims 1 to 9, or the controller according to claim 10.

12. An air conditioner, characterized in that: The outdoor unit comprises the signal sampling circuit according to any one of claims 1 to 9, or the controller according to claim 10, or the outdoor unit according to claim 11.

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