Current sampling circuit and air conditioner
By combining a single-resistor sampling circuit with a half-wave inverting module and an adder module, the problems of complex circuit structure and high cost in existing compressor current monitoring circuits are solved, achieving circuit simplification and cost savings, and improving sampling accuracy and reliability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-14
- Publication Date
- 2026-03-17
AI Technical Summary
In existing compressor current monitoring circuits, the use of multiple diodes results in complex circuit structures and high costs.
A single-resistor sampling circuit is used, combined with a half-wave inverting module and an adder module. The sampling voltage is obtained by sampling through a single resistor, and the absolute value is taken by the half-wave inverting module and the adder module to output a positive voltage, which simplifies the circuit structure and reduces the use of diodes.
This simplifies the circuit structure and reduces costs, while improving the accuracy of sampling current acquisition and the reliability of the circuit.
Smart Images
Figure CN224005168U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of electronic technology, specifically to a current sampling circuit and an air conditioner. Background Technology
[0002] As the heart of the entire air conditioning refrigeration cycle, the operating status of the air conditioner compressor directly affects the overall efficiency and lifespan of the unit. Because compressors typically operate under high load conditions, they are also one of the most prone to failure components in an air conditioning system. Therefore, accurate and real-time compressor current monitoring can promptly detect abnormalities and take corrective action, preventing potential problems from leading to greater losses.
[0003] In current compressor current monitoring circuits, a current sampling circuit consisting of six diodes forming positive and negative half-waves is used to ensure the integrity of the sampled current signal. However, this circuit has many components, is complex in design, and is costly.
[0004] Therefore, the technology still needs to be improved and enhanced. Utility Model Content
[0005] This application provides a current sampling circuit and an air conditioner that can alleviate the problems of complex circuit structure and high cost caused by setting multiple diodes in the current detection circuit of the compressor.
[0006] This application provides a current sampling circuit, which is applied in an air conditioner. The air conditioner includes a compressor, and the current sampling circuit includes:
[0007] The sampling resistor is used to sample the input AC voltage to output the corresponding sampled voltage.
[0008] The half-wave inverting module is connected to one end of the sampling resistor. The half-wave inverting module is used to invert and amplify the negative half-wave in the sampling voltage, and output a positive half-wave voltage with an amplitude greater than the sampling voltage.
[0009] The adder module is connected to one end of the sampling resistor and the half-wave inverting module respectively. The adder module is used to invert the sampled voltage and then superimpose it with the sampled voltage to output a positive voltage.
[0010] In some embodiments of the current sampling circuit, the current sampling circuit further includes a filtering module, which is used to filter the positive phase voltage.
[0011] In some embodiments of the current sampling circuit, the half-wave inverting module includes a first resistor, a second resistor, a first diode, a second diode, and a first operational amplifier. One end of the first resistor is connected to one end of the sampling resistor, and the other end of the first resistor is connected to the inverting input terminal of the first operational amplifier. One end of the second resistor and the cathode of the first diode are both connected to the inverting input terminal of the first operational amplifier. The anode of the first diode and the cathode of the second diode are both connected to the output terminal of the first operational amplifier. The non-inverting input terminal of the first operational amplifier is grounded. The other end of the second resistor is connected to the anode of the second diode, and the anode of the second diode is connected to the adder module.
[0012] In some embodiments of the current sampling circuit, the adder module includes a third resistor, a fourth resistor, a fifth resistor, and a second operational amplifier. One end of the third resistor is connected to the positive terminal of the second diode, and the other end of the third resistor is connected to the inverting input terminal of the second operational amplifier. One end of the fourth resistor and one end of the fifth resistor are both connected to the inverting input terminal of the second operational amplifier. The other end of the fourth resistor is connected to one end of the sampling resistor, and the other end of the fifth resistor is connected to the output terminal of the second operational amplifier. The non-inverting input terminal of the second operational amplifier is grounded.
[0013] In some embodiments of the current sampling circuit, the filtering module includes a sixth resistor and a first capacitor. One end of the sixth resistor is connected to the adder module, and the other end of the sixth resistor is connected to the output terminal of the positive phase voltage. One end of the first capacitor is connected to the other end of the sixth resistor, and the other end of the first capacitor is grounded.
[0014] In some embodiments of the current sampling circuit, the current sampling circuit further includes an amplification module, which is connected to one end of the sampling resistor, a half-wave inverting module, and an adder module.
[0015] The amplification module is used to amplify the sampled voltage and output it to the half-wave inverting module and the adder module respectively.
[0016] In some embodiments of the current sampling circuit, the current sampling circuit further includes an overcurrent protection module connected to the adder module. The overcurrent protection module is used to obtain the corresponding sampling current based on the positive phase voltage output by the adder module, and output a feedback signal based on the sampling current.
[0017] In some embodiments of the current sampling circuit, the amplification module includes a third operational amplifier, a seventh resistor, and an eighth resistor. One end of the seventh resistor is connected to one end of the sampling resistor, and the other end of the seventh resistor and one end of the eighth resistor are both connected to the inverting input terminal of the third operational amplifier. The non-inverting input terminal of the third operational amplifier is grounded, and the other end of the eighth resistor is connected to the output terminal of the third operational amplifier. The output terminal of the third operational amplifier is connected to the half-wave inverting module and the adder module, respectively.
[0018] In some embodiments of the current sampling circuit, the overcurrent protection module includes a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a second capacitor, and a comparator. One end of the ninth resistor is energized, and the other end of the ninth resistor and one end of the tenth resistor are both connected to the non-inverting input of the comparator. The other end of the tenth resistor is grounded. One end of the second capacitor is connected to the non-inverting input of the comparator, and the other end of the second capacitor is grounded. One end of the eleventh resistor is connected to the adder module, and the other end of the eleventh resistor is connected to the inverting input of the comparator. One end of the twelfth resistor is connected to the output of the comparator, and the other end of the twelfth resistor is energized. The output of the comparator is connected to the output of the feedback signal.
[0019] This application also provides an air conditioner, which includes the aforementioned current sampling circuit.
[0020] This application provides a current sampling circuit and an air conditioner. The current sampling circuit uses a single resistor to sample the corresponding voltage, and then uses a half-wave inverting module and an adder module to take the absolute value of the sampled voltage and output a positive-phase voltage to obtain the corresponding sampled current. This current sampling circuit uses a single resistor for sampling and does not require multiple diodes, effectively simplifying the circuit structure and saving costs. Attached Figure Description
[0021] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.
[0022] Figure 1 This is a first structural block diagram of the current sampling circuit provided in an embodiment of this application.
[0023] Figure 2 A second structural block diagram of the current sampling circuit provided in the embodiments of this application.
[0024] Figure 3 The circuit diagram of the half-wave inverting module, adder module and filter module in the current sampling circuit provided in the embodiments of this application.
[0025] Figure 4 The waveforms of the sinusoidal voltage and the positive phase voltage in the current sampling circuit provided in the embodiments of this application are shown.
[0026] Figure 5 The circuit diagram shows the amplification module and overcurrent protection module of the current sampling circuit provided in the embodiments of this application. Detailed Implementation
[0027] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.
[0028] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Features thus defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.
[0029] Please see Figure 1 This application provides an air conditioner, which includes a compressor 10, an intelligent power module 20, a current sampling circuit 30, and a main control chip 40. The intelligent power module 20 is connected to both the compressor 10 and the current sampling circuit 30, which is also connected to the main control chip 40. The intelligent power module 20 drives the compressor 10 to operate based on the input AC voltage, and the current sampling circuit 30 samples the AC voltage input to the intelligent power module 20 to obtain a corresponding sampled current, which is then fed back to the main control chip 40.
[0030] The current sampling circuit 30 includes a sampling resistor R0, a half-wave inverting module 31, and an adder module 32. One end of the sampling resistor is connected to the intelligent power module 20, and the other end of the sampling resistor R0 is grounded. The half-wave inverting module 31 and the adder module 32 are both connected to one end of the sampling resistor. The adder module 32 is also connected to the half-wave inverting module 31 and the main control chip.
[0031] The sampling resistor R0 is used to sample the AC voltage input to the intelligent power module 20 to output a corresponding sampled voltage. The half-wave inverting module 31 and the adder module 32 are connected to one end of the sampling resistor R0 to obtain the voltage at one end of the sampling resistor, which is a sinusoidal voltage. The half-wave inverting module 31 amplifies the negative half-wave of the sampled voltage and outputs a positive half-wave voltage with an amplitude greater than the sampled voltage to the adder module 32. The adder module 32 inverts the sampled voltage, superimposes it with the sampled voltage, and outputs a positive voltage to the main control chip 40. The main control chip 40 obtains the corresponding sampled current based on this positive voltage, thereby achieving current sampling of the compressor 10.
[0032] In this embodiment, the current sampling circuit 30 uses a single resistor to sample the corresponding voltage. The absolute value of this sampled voltage is then taken by the half-wave inverting module 31 and the adder module 32 to output a positive-phase voltage, thus facilitating the acquisition of the corresponding sampled current. This current sampling circuit 30 uses a single resistor for sampling and does not require multiple diodes, effectively simplifying the circuit structure and saving costs.
[0033] Please see Figure 2 In some embodiments, the current sampling circuit 30 further includes a filtering module 33, which is used to filter the positive phase voltage. In this embodiment, the filtering module 33 filters the positive phase voltage output by the adder module 32, which helps to improve the stability of the positive phase voltage and thus improve the reliability of the circuit.
[0034] In some embodiments, the current sampling circuit 30 further includes an amplification module 34 and an overcurrent protection module 35. The amplification module 34 is connected to one end of the sampling resistor R0, the half-wave inverting module 31, and the adder module 32. The overcurrent protection module 35 is connected to the adder module 32.
[0035] The amplification module 34 amplifies the sampled voltage and outputs it to the half-wave inverting module 31 and the adder module 32 respectively. The overcurrent protection module 35 obtains the corresponding sampled current based on the positive phase voltage output by the adder module 32 and outputs a feedback signal to the main control chip 40 based on the sampled current, so as to realize the overcurrent protection of the compressor 10.
[0036] In this embodiment, the current sampling circuit 30 uses single-resistor sampling. To avoid the signal at the sampling resistor R0 being weak and easily interfered with, the sampled voltage is first amplified by the amplification module 34 before being output to the half-wave inverting module 31 and the adder module 32. Simultaneously, an overcurrent protection module 35 is connected in parallel at the output of the adder module 32, which can output a feedback signal based on the magnitude of the sampled current, without interfering with the current sampling process. Therefore, the current sampling circuit 30 in this application uses single-resistor sampling, achieving integrated sampling and protection, simplifying the circuit structure and saving costs.
[0037] Please see Figure 3As one embodiment, the half-wave inverting module 31 includes a first resistor R1, a second resistor R2, a first diode D1, a second diode D2, and a first operational amplifier U1. One end of the first resistor R1 is connected to the amplification module 34, and the other end of the first resistor R1 is connected to the inverting input terminal of the first operational amplifier U1. One end of the second resistor R2 and the cathode of the first diode D1 are both connected to the inverting input terminal of the first operational amplifier U1. The anode of the first diode D1 and the cathode of the second diode D2 are both connected to the output terminal of the first operational amplifier U1. The non-inverting input terminal of the first operational amplifier U1 is grounded. The other end of the second resistor R2 is connected to the anode of the second diode D2, and the anode of the second diode D2 is connected to the adder module 32.
[0038] In this embodiment, the first diode D1 and the second diode D2 are model 1N4148, and the first resistor R1 and the second resistor R2 can have the same resistance value of 1KΩ. The half-wave inverting module 31 in this embodiment uses two diodes, resistors, and an operational amplifier to invert and amplify the negative half-wave of the sinusoidal voltage to obtain a half-wave positive voltage. The waveform of this half-wave positive voltage is as follows: Figure 4 As shown in L1, according to the figure, the amplitude of the half-wave positive voltage in this embodiment is twice the amplitude of the sine wave voltage.
[0039] In one embodiment, the adder module 32 includes a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a second operational amplifier U2. One end of the third resistor R3 is connected to the positive terminal of the second diode D2, and the other end of the third resistor R3 is connected to the inverting input terminal of the second operational amplifier U2. One end of the fourth resistor R4 and one end of the fifth resistor R5 are both connected to the inverting input terminal of the second operational amplifier U2. The other end of the fourth resistor R4 is connected to the amplification module 34, and the other end of the fifth resistor R5 is connected to the output terminal of the second operational amplifier U2. The non-inverting input terminal of the second operational amplifier U2 is grounded.
[0040] The fourth resistor R4 can have a resistance of 2KΩ, while the third resistor R3 and the fifth resistor R5 can both have a resistance of 1KΩ. The inverting input of the second operational amplifier U2 is connected to the half-wave inverting module 31 and the amplification module 34. The second operational amplifier U2 inverts the sinusoidal voltage output from the amplification module 34 to obtain an inverted voltage, the waveform of which is shown below. Figure 4 As shown in L2, the inverted voltage is superimposed with the half-wave positive voltage to obtain the forward voltage. The waveform of the forward voltage is shown in the figure below. Figure 4 As shown in L3; the frequency of the positive phase voltage is twice that of the sinusoidal voltage, and the amplitude is the same, i.e., V out = | V in | .
[0041] Please continue reading. Figure 3 In one embodiment, the filter module 33 includes a sixth resistor R6 and a first capacitor C1. One end of the sixth resistor R6 is connected to the output terminal of the second operational amplifier U2, and the other end of the sixth resistor R6 is connected to the output terminal of the positive voltage. One end of the first capacitor C1 is connected to the other end of the sixth resistor R6, and the other end of the first capacitor C1 is grounded. In this embodiment, the sixth resistor R6 and the first capacitor C1 form an RC filter circuit to filter the inverted voltage, thereby improving the reliability of the sampled signal.
[0042] The half-wave inverting module 31 and the adder module 32 invert the negative half-wave of the input sine wave voltage to obtain a positive phase voltage, the frequency of which is twice that of the original sine wave voltage. This positive phase voltage is then filtered by an RC circuit to obtain a stable voltage value. The ADC sampling port of the main control chip 40 reconstructs the amplitude of the corresponding current-voltage signal based on this positive phase voltage, enabling the digital conversion of the sampled current signal and supplying it to the main control chip 40 for rapid control and computation. Therefore, in this embodiment, the effective value conversion of the AC signal is directly completed through a hardware circuit structure, eliminating the need for calculations by the main control chip 40 and reducing its resource consumption and computational load.
[0043] Please see Figure 5 In one embodiment, the amplification module 34 includes a third operational amplifier U3, a seventh resistor R7, and an eighth resistor R8. One end of the seventh resistor R7 is connected to one end of the sampling resistor R0. The other end of the seventh resistor R7 and one end of the eighth resistor R8 are both connected to the inverting input terminal of the third operational amplifier U3. The non-inverting input terminal of the third operational amplifier U3 is grounded. The other end of the eighth resistor R8 is connected to the output terminal of the third operational amplifier U3. The output terminal of the third operational amplifier U3 is connected to the half-wave inverting module 31 and the adder module 32. In this embodiment, the sampling voltage of the sampling resistor R0 is amplified by the third operational amplifier U3, which can improve the anti-interference capability of the sampling signal and thus improve the sampling accuracy.
[0044] Please continue reading. Figure 5In one embodiment, the overcurrent protection module 35 includes a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a second capacitor C2, and a comparator U4. One end of the ninth resistor R9 is energized, and the other ends of both the ninth resistor R9 and one end of the tenth resistor R10 are connected to the non-inverting input of the comparator U4. The other end of the tenth resistor R10 is grounded. One end of the second capacitor C2 is connected to the non-inverting input of the comparator U4, and the other end is grounded. One end of the eleventh resistor R11 is connected to the other end of the sixth resistor R6, and the other end of the eleventh resistor R11 is connected to the inverting input of the comparator U4. One end of the twelfth resistor R12 is connected to the output of the comparator U4, and the other end of the twelfth resistor R12 is energized. The output of the comparator U4 is connected to the output of the feedback signal. In this embodiment, by setting the comparator U4 for overcurrent protection, the overcurrent protection response is fast and does not interfere with current sampling, thereby improving the reliability of the circuit.
[0045] This application also provides a current sampling circuit, which will not be described in detail here, as the current sampling circuit has been described in detail above.
[0046] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.
[0047] The current sampling circuit provided in the embodiments of this application has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.
Claims
1. A current sampling circuit applied to an air conditioner, the air conditioner comprising a compressor, characterized in that, The current sampling circuit comprises: a sampling resistor for sampling an alternating voltage connected to output a corresponding sampling voltage; a half-wave inversion module connected to one end of the sampling resistor, for inverting and amplifying a negative half-wave of the sampling voltage to output a half-wave positive voltage with a larger amplitude than the sampling voltage; an adder module connected to the other end of the sampling resistor and the half-wave inversion module, for inverting the sampling voltage and adding it to the sampling voltage to output a positive voltage.
2. The current sampling circuit of claim 1, wherein, The current sampling circuit further comprises a filter module for filtering the positive voltage.
3. The current sampling circuit of claim 1, wherein, The half-wave inversion module comprises a first resistor, a second resistor, a first diode, a second diode and a first operational amplifier, one end of the first resistor is connected to one end of the sampling resistor, the other end of the first resistor is connected to the inverting input terminal of the first operational amplifier, one end of the second resistor and the negative electrode of the first diode are both connected to the inverting input terminal of the first operational amplifier, the positive electrode of the first diode and the negative electrode of the second diode are both connected to the output terminal of the first operational amplifier, the positive input terminal of the first operational amplifier is grounded, the other end of the second resistor is connected to the positive electrode of the second diode, and the positive electrode of the second diode is connected to the adder module.
4. The current sampling circuit of claim 3, wherein, The adder module comprises a third resistor, a fourth resistor, a fifth resistor and a second operational amplifier, one end of the third resistor is connected to the positive electrode of the second diode, the other end of the third resistor is connected to the inverting input terminal of the second operational amplifier, one end of the fourth resistor and one end of the fifth resistor are both connected to the inverting input terminal of the second operational amplifier, the other end of the fourth resistor is connected to one end of the sampling resistor, the other end of the fifth resistor is connected to the output terminal of the second operational amplifier, and the positive input terminal of the second operational amplifier is grounded.
5. The current sampling circuit of claim 2, wherein, The filter module comprises a sixth resistor and a first capacitor, one end of the sixth resistor is connected to the adder module, the other end of the sixth resistor is connected to the output terminal of the positive voltage, one end of the first capacitor is connected to the other end of the sixth resistor, and the other end of the first capacitor is grounded.
6. The current sampling circuit of any of claims 1-5, wherein, The current sampling circuit further comprises an amplification module connected to one end of the sampling resistor, the half-wave inversion module and the adder module; The amplification module is configured to amplify the sampling voltage and output it to the half-wave inversion module and the adder module respectively.
7. The current sampling circuit of claim 6, wherein, The current sampling circuit further comprises an overcurrent protection module connected to the adder module, the overcurrent protection module is configured to obtain a corresponding sampling current according to the positive voltage output by the adder module, and output a feedback signal according to the sampling current.
8. The current sampling circuit of claim 6, wherein, The amplification module comprises a third operational amplifier, a seventh resistor and an eighth resistor, one end of the seventh resistor is connected with one end of the sampling resistor, the other end of the seventh resistor and one end of the eighth resistor are both connected with the inverting input terminal of the third operational amplifier, the non-inverting input terminal of the third operational amplifier is grounded, the other end of the eighth resistor is connected with the output terminal of the third operational amplifier, and the output terminal of the third operational amplifier is connected with the half-wave inversion module and the adder module respectively.
9. The current sampling circuit of claim 7, wherein, The overcurrent protection module comprises a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a second capacitor and a comparator, one end of the ninth resistor is connected with electricity, the other end of the ninth resistor and one end of the tenth resistor are both connected with the non-inverting input terminal of the comparator, the other end of the tenth resistor is grounded, one end of the second capacitor is connected with the non-inverting input terminal of the comparator, the other end of the second capacitor is grounded, one end of the eleventh resistor is connected with the adder module, the other end of the eleventh resistor is connected with the inverting input terminal of the comparator, one end of the twelfth resistor is connected with the output terminal of the comparator, the other end of the twelfth resistor is connected with electricity, and the output terminal of the comparator is connected with the output terminal of the feedback signal.
10. An air conditioner characterized by comprising: The air conditioner comprises the current sampling circuit according to any one of claims 1-9.