Current acquisition filter circuit and method and electronic equipment

Abstract

The invention provides a current acquisition filter circuit, a current acquisition filter method and electronic equipment. The circuit comprises a current transformer configured to receive an initial input current and convert the initial input current into a target input current; the first filter circuit is electrically connected with the current transformer and is configured to receive the target input current sent by the current transformer and filter the target input current to obtain a first filter current with a preset frequency; the suppression circuit is electrically connected with the first filter circuit and is configured to receive the first filter current sent by the first filter circuit and filter the first filter current to obtain a second filter current; the sampling circuit is electrically connected with the suppression circuit and is configured to receive the second filtering current sent by the suppression circuit and convert the second filtering current into sampling voltage; and the second filter circuit is electrically connected with the sampling circuit and is configured to receive the sampling voltage sent by the sampling circuit and filter the sampling voltage to obtain a target voltage.

Description

Technical Field

[0001] The present disclosure relates to the field of signal processing technology, and in particular to a current acquisition filter circuit, method and electronic equipment. Background Art

[0002] With the development of circuit breakers, enhanced intelligent circuit breakers can be deployed in important industrial parks. However, due to the complex installation environment of circuit breakers, they are easily affected by the electromagnetic environment, especially under the conduction interference induced by the radio frequency field, which will cause inaccurate current collection.

[0003] In view of this, how to avoid inaccurate current collection of circuit breaker caused by conducted interference induced by radio frequency field has become a technical problem that needs to be solved urgently. Summary of the invention

[0004] In view of this, the purpose of the present disclosure is to provide a current acquisition filter circuit, method and electronic device to solve or partially solve the above technical problems.

[0005] Based on the above purpose, the first aspect of the present disclosure proposes a current acquisition filter circuit, comprising:

[0006] A current transformer configured to receive an initial input current and convert the initial input current into a target input current;

[0007] a first filtering circuit, electrically connected to the current transformer, configured to receive the target input current sent by the current transformer, and filter the target input current to obtain a first filtered current of a preset frequency;

[0008] a suppression circuit, electrically connected to the first filter circuit, configured to receive the first filter current sent by the first filter circuit, and filter the first filter current to obtain a second filter current;

[0009] a sampling circuit, electrically connected to the suppression circuit, configured to receive the second filtered current sent by the suppression circuit, and convert the second filtered current into a sampling voltage;

[0010] The second filtering circuit is electrically connected to the sampling circuit, and is configured to receive the sampling voltage sent by the sampling circuit, and filter the sampling voltage to obtain a target voltage.

[0011] Based on the same inventive concept, the second aspect of the present disclosure proposes a current acquisition filtering method, which is applied to a current acquisition filtering circuit; the current acquisition filtering circuit comprises: a current transformer, a first filtering circuit, a suppression circuit, a sampling circuit, and a second filtering circuit; the method comprises:

[0012] The current transformer receives an initial input current and converts the initial input current into a target input current;

[0013] The first filtering circuit receives the target input current sent by the current transformer, and performs filtering on the target input current to obtain a first filtered current with a preset frequency;

[0014] The suppression circuit receives the first filter current sent by the first filter circuit, and performs filtering on the first filter current to obtain a second filter current;

[0015] The sampling circuit receives the second filtered current sent by the suppression circuit and converts the second filtered current into a sampling voltage;

[0016] The second filtering circuit receives the sampled voltage sent by the sampling circuit, and filters the sampled voltage to obtain a target voltage.

[0017] Based on the same inventive concept, the third aspect of the present disclosure proposes an electronic device, including a memory, a processor, and a computer program stored in the memory and executable by the processor, wherein the processor implements the method as described above when executing the computer program.

[0018] From the above, it can be seen that the current acquisition filter circuit, method and electronic device provided by the present disclosure. The current acquisition filter circuit includes: a current transformer, a first filter circuit, a suppression circuit, a sampling circuit and a second filter circuit. The first filter circuit filters the target input current to obtain a first filtered current of a preset frequency. The suppression circuit filters the first filtered current to obtain a second filtered current. The sampling circuit converts the second filtered current into a sampling voltage. The second filter circuit filters the sampling voltage to obtain a target voltage. By setting the first filter circuit in the current acquisition filter circuit, the problem of realizing high-precision current acquisition under the conducted interference induced by the radio frequency field is solved, the anti-interference ability is strong, the circuit structure is simple and easy to implement, the manufacturing cost is low, the space occupied is small, and the cut-off frequency of the filter can be flexibly controlled by adjusting the resistance value of the first resistor and the capacitance value of the first capacitor, and can be used in multiple fields such as enhanced intelligent circuit breakers, smart meters, and smart energy units. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the present disclosure or related technologies, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, the drawings described below are only embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0020] Figure 1A schematic diagram of a current collection and filtering circuit according to an embodiment of the present disclosure;

[0021] Figure 2 A schematic diagram of a current collection and filtering circuit according to another embodiment of the present disclosure;

[0022] Figure 3 A schematic diagram of a current collection and filtering circuit with a protection circuit added according to an embodiment of the present disclosure;

[0023] Figure 4 This is a flow chart of the current collection and filtering method according to an embodiment of the present disclosure;

[0024] Figure 5 The first output waveform of the embodiment of the present disclosure without the first filtering circuit;

[0025] Figure 6 The second output waveform of the embodiment of the present disclosure without the first filtering circuit;

[0026] Figure 7 is the output waveform of the current acquisition filter circuit of the embodiment of the present disclosure;

[0027] Figure 8 It is a schematic diagram of the structure of an electronic device according to an embodiment of the present disclosure.

[0028] Description of reference numerals:

[0029] 100. Current collection filter circuit;

[0030] 110, current transformer, 120, first filter circuit, 130, suppression circuit, 140, sampling circuit, 150, second filter circuit, 160, protection circuit;

[0031] T1, current transformer, R1, first resistor, C1, first capacitor, B1, first magnetic bead, B2, second magnetic bead, D1, first protection circuit, D2, second protection circuit, R4, fourth resistor, R5, fifth resistor, R2, second resistor, C2, second capacitor, R3, third resistor, C3, third capacitor. DETAILED DESCRIPTION

[0032] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0033] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the embodiments of the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. "Including" or "comprising" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0034] With the development of high-proportion renewable energy technologies, more and more distributed photovoltaic and DC loads will appear in low-voltage distribution networks, posing more serious challenges to the protection of low-voltage distribution networks, line losses, power quality management, etc., which the current low-voltage circuit breakers cannot cope with. With the introduction of the concept of distribution Internet of Things, there is a demand for intelligent low-voltage circuit breakers. It uses microprocessors as core control components and comprehensively uses advanced sensing, photoelectric conversion, digital control, microelectronics, data communication, edge computing, information processing, software-defined chips, software-defined functions and other technologies to efficiently integrate mutual inductance equipment, primary switch equipment and intelligent control devices, and then integrate them with traditional circuit breakers to realize modular architecture and build a new generation of intelligent, communicative and modular circuit breakers.

[0035] The communication capability is mainly reflected in the communication chip or circuit added to the control unit, which is connected to the host computer through the transmission medium for monitoring or information exchange with other devices. At present, serial lines or field buses are generally embedded in intelligent circuit breakers to match the development trend of intelligent power grids. Driven by new technologies, the new generation of modular circuit breakers of low-voltage electrical appliances has improved the manufacturing efficiency and market adaptability of products. The scope of use is not limited to a specific model of circuit breakers, which prevents the disadvantage of replacing the entire machine due to damage to a single component. In this way, the system maintenance will be relatively simple and meet the environmental protection needs of product material saving and energy saving.

[0036] The current low-voltage circuit breakers on the market are relatively mature in terms of circuit breaking and protection, but are still in the early stages of supporting the construction of ubiquitous power Internet of Things. Real-time data of the high-voltage power grid is obtained through intelligent sensor technology, and calculations are performed through microprocessors to achieve online monitoring and diagnosis of power grid equipment; digital communication technology is used to achieve process monitoring and computer monitoring.

[0037] At present, the power detection function of intelligent circuit breakers has expanded from meeting the needs of circuit breaker overcurrent protection to real-time and rapid collection and display of various electrical parameters of the power grid, providing reliable data for distribution system operation managers to grasp the quality of the power grid in a timely manner. Facing the opportunity of building a new power system, circuit breakers are rapidly developing in the direction of real-time, stability, and communication capabilities with a high degree of intelligence, communication networking, and product modularization as the main orientation. At present, the installation environment of circuit breakers is complex, especially when the requirements are high. How to make the circuit breaker realize high-precision current collection under the conduction interference induced by the radio frequency field has become an urgent problem to be solved.

[0038] The deployment of enhanced intelligent circuit breakers can be based on the adjustable needs of multiple loads, combined with the on-site coverage planning and design of its communication capabilities and the intelligence level of multiple loads, and can be deployed in low-voltage feeders, branch lines, and other important industrial parks, public or a certain enterprise's power equipment, charging equipment, distributed energy storage, distributed power generation and other single equipment locations. The on-site installation environment is complex and easily affected by the electromagnetic environment, especially under the conduction interference induced by the radio frequency field, resulting in inaccurate current collection.

[0039] At present, the main methods to ensure the accuracy of current acquisition under the conducted interference induced by the RF field are differential input circuit and voltage conversion circuit. The differential input circuit can ensure the phase accuracy of the sampled current, but the input impedance of the differential amplifier in the differential input circuit is very low, which is related to its matching resistance, and the impedance of the two input ends of the differential amplifier is not symmetrical. The resistance of the differential amplifier will have errors, resulting in resistance mismatch, which greatly reduces the common mode rejection ratio CMRR, resulting in a decrease in the differential amplifier's ability to suppress common mode interference, and may introduce additional noise; the voltage difference between the input and output of the voltage conversion circuit cannot be too large, the load capacity is weak, and the cost is high.

[0040] The terminal-side equipment in the industrial park is the basis for realizing load information collection, status monitoring, localized analysis and decision-making, and flexible load regulation within the park. The circuit breaker has insufficient perception capabilities and lacks load broadband and high-precision metering functions. At the same time, it mostly adopts a single communication method. The reliability of data transmission is easily affected by the complex electromagnetic interference in the park, and it is difficult to support the deep perception and flexible regulation of multiple loads in the park. It is necessary to carry out modular intelligent upgrades of smart circuit breakers. However, the sensor measurement circuit is closely connected with the circuit breaker body line protection circuit, and the power consumption and size of the multi-modal communication module are relatively large. How to realize the high-precision metering function of the smart circuit breaker under the influence of complex electromagnetic interference, especially under the conducted interference induced by the radio frequency field, is a technical problem to be solved by the embodiments of the present disclosure.

[0041] Conducted interference induced by radio frequency fields refers to the phenomenon that external radio frequency electromagnetic fields enter the interior of electronic equipment through cables, wires and other conductive paths, thereby interfering with the normal operation of the equipment. This interference may cause equipment performance degradation, data errors or even complete paralysis. The electromagnetic field can act on the entire cable connected to the interfered enhanced intelligent circuit breakers, smart meters, smart energy units and other devices, mainly signals in the frequency range of 150kHz-80MHz. Although the size of the interfered device is usually shorter than the wavelength of the interference signal frequency, the input and output lines connected to the interfered device, such as power lines, control lines, interface cables, etc., are usually several wavelengths long, so they are likely to become passive receiving antenna networks. Sensitive devices connected to the cable network in resonant mode, such as enhanced intelligent circuit breakers, smart meters, smart energy units and other devices, are susceptible to interference currents flowing through the cable network, causing sensitive devices to fail or work effectively, thereby affecting high-precision metering functions.

[0042] As mentioned above, how to avoid inaccurate current collection of circuit breaker caused by conducted interference induced by RF field has become an important research issue.

[0043] Based on the above description, if Figure 1 As shown, the current collection and filtering circuit 110 proposed in this embodiment includes:

[0044] The current transformer 110 is configured to receive an initial input current and convert the initial input current into a target input current.

[0045] The first filtering circuit 120 is electrically connected to the current transformer 110, and is configured to receive the target input current sent by the current transformer, and filter the target input current to obtain a first filtered current of a preset frequency.

[0046] The suppression circuit 130 is electrically connected to the first filtering circuit 120, and is configured to receive the first filtering current sent by the first filtering circuit, and filter the first filtering current to obtain a second filtering current.

[0047] The sampling circuit 140 is electrically connected to the suppression circuit 130 , and is configured to receive the second filtered current sent by the suppression circuit, and convert the second filtered current into a sampling voltage.

[0048] The second filtering circuit 150 is electrically connected to the sampling circuit 140 , and is configured to receive the sampling voltage sent by the sampling circuit, and filter the sampling voltage to obtain a target voltage.

[0049] In specific implementation, the current acquisition filter circuit 110 utilizes a design method that combines the first filter circuit 120 (RC filter circuit), the current transformer 110, and the sampling circuit 140 to ensure that enhanced intelligent circuit breakers, smart meters, smart energy units and other equipment can achieve high-precision current acquisition under the influence of complex electromagnetic interference, especially under the conduction interference induced by radio frequency fields.

[0050] The current transformer 110 converts the initial input current into the target input current, thereby converting the large current on the primary side into a small current on the secondary side. The first filter current 120 is an RC filter circuit. By setting the resistance value and the capacitance value in the first filter circuit 120, the cut-off frequency can be set, so that interference signals of different frequencies can be filtered. The suppression circuit 130 is resistive at high frequencies, and is used to suppress high-frequency signals and eliminate RF noise and radio frequency energy in the transmission line structure, suppress high-frequency noise and spike interference on the signal line and the sound source line, and has the ability to absorb electrostatic pulses, thereby reducing electromagnetic interference. The sampling circuit 140 converts the second filtered current into a sampling voltage, thereby converting the small current on the secondary side into a voltage signal. The second filter circuit 150 can further process the radio frequency signal, thereby ensuring that the circuit breaker can achieve high-precision current acquisition under the conducted interference induced by the radio frequency field.

[0051] Through the above embodiments, by setting the RC first filtering circuit in the current collection filtering circuit, the problem of realizing high-precision current collection under the conduction interference induced by the radio frequency field is solved, the anti-interference ability is strong, the circuit structure is simple and easy to implement, the manufacturing cost is low, the space occupied is small, and the cut-off frequency of the RC filter can be flexibly controlled by adjusting the resistance value of the first resistor R1 and the capacitance value of the first capacitor C1, and it can be used in multiple fields such as enhanced intelligent circuit breakers, smart meters, and smart energy units.

[0052] In some embodiments, Figure 2 As shown, the first filter circuit 120 includes: a first resistor R1 and a first capacitor C1.

[0053] The first end of the first resistor R1 is electrically connected to the first end of the current transformer T1, the second end of the first resistor R1 is electrically connected to the first end of the first capacitor C1, and the second end of the first capacitor C1 is electrically connected to the second end of the current transformer T1.

[0054] In a specific implementation, the first filter circuit 120 includes: a first resistor R1 and a first capacitor C1. By setting the resistance value of the first resistor R1 and the capacitance value of the first capacitor C1, the cutoff frequency can be set, thereby allowing the first filter current of a preset frequency to pass.

[0055] Specifically, the cut-off frequency is determined according to the resistance value of the first resistor and the capacitance value of the first capacitor. Among them, f L is the cut-off frequency, R1 is the resistance value of the first resistor, and C1 is the capacitance value of the first capacitor.

[0056] Through the above scheme, by setting the resistance value of the first resistor R1 and the capacitance value of the first capacitor C1, the cut-off frequency can be set, thereby allowing the first filter current of the preset frequency to pass through. In this way, it can play a good filtering role and allow the waveform of the preset frequency to pass through, thereby achieving filtering and signal conditioning.

[0057] In some embodiments, Figure 2 As shown, the suppression circuit 130 includes: a first magnetic bead B1 and a second magnetic bead B2.

[0058] The first end of the first magnetic bead B1 is electrically connected to the first end of the first resistor R1 , and the first end of the second magnetic bead B2 is electrically connected to the second end of the first capacitor C1 .

[0059] In a specific implementation, the suppression circuit 130 includes: a first magnetic bead B1 and a second magnetic bead B2 , wherein the first magnetic bead B1 is electrically connected to the first resistor R1 in the first filter circuit 120 , and the second magnetic bead B2 is electrically connected to the first capacitor C1 in the first filter circuit 120 .

[0060] The first magnetic bead B1 and the second magnetic bead B2 are resistive at high frequencies and are used to suppress high-frequency signals and eliminate RF noise and radio frequency energy in the transmission line structure, suppress high-frequency noise and spike interference on the signal line and the sound source line, and have the ability to absorb electrostatic pulses, thereby reducing electromagnetic interference.

[0061] Through the above scheme, after the first filter circuit 120 filters the target input current to obtain the first filtered current, the high-frequency signal in the first filtered current is further filtered using the first magnetic bead B1 and the second magnetic bead B2 in the suppression circuit 130, thereby further reducing electromagnetic interference.

[0062] In some embodiments, Figure 3 As shown, the current collection filter circuit 100 also includes: a protection circuit 160; Figure 2 As shown, the protection circuit 160 includes: a first protection circuit D1 and a second protection circuit D2.

[0063] The first protection circuit D1 includes: a first diode and a second diode, wherein the anode of the first diode and the cathode of the second diode are electrically connected to the second end of the first magnetic bead B1, and the cathode of the first diode is electrically connected to the anode of the second diode and is grounded.

[0064] The second protection circuit D2 includes: a third diode and a fourth diode, wherein the anode of the third diode and the cathode of the fourth diode are electrically connected to the second end of the second magnetic bead B2, and the cathode of the third diode is electrically connected to the anode of the fourth diode and is grounded.

[0065] In a specific implementation, the current collection and filtering circuit 100 further includes: a protection circuit 160. The protection circuit 160 includes: a first protection circuit D1 and a second protection circuit D2.

[0066] The first end of the first protection circuit D1 is electrically connected to the first magnetic bead B1, and the second end of the first protection circuit D1 is grounded. The first end of the second protection circuit D2 is electrically connected to the second magnetic bead B2, and the second end of the second protection circuit D2 is grounded.

[0067] The first protection circuit D1 and the second protection circuit D2 both include two reversely arranged diodes (bidirectional protection diodes). The first protection circuit D1 includes two reversely arranged first diodes and second diodes, the positive pole of the first diode and the negative pole of the second diode are electrically connected to the first magnetic bead B1, and the negative pole of the first diode and the positive pole of the second diode are electrically connected and grounded. The second protection circuit D2 includes two reversely arranged third diodes and fourth diodes, the positive pole of the third diode and the negative pole of the fourth diode are electrically connected to the second magnetic bead B2, and the negative pole of the third diode is electrically connected to the positive pole of the fourth diode and grounded.

[0068] The bidirectional protection diodes in the first protection circuit D1 and the second protection circuit D2 can prevent the current from flowing in the reverse direction, thus protecting the circuits.

[0069] Through the above scheme, the first protection circuit D1 includes two first diodes and a second diode arranged in reverse, and the second protection circuit D2 includes two third diodes and a fourth diode arranged in reverse, which can prevent the current from flowing in reverse, thereby playing the role of protecting the circuit.

[0070] In some embodiments, Figure 2 As shown, the sampling circuit 140 includes: a fourth resistor R4 and a fifth resistor R5.

[0071] The first end of the fourth resistor R4 is electrically connected to the second end of the first magnetic bead B1 , the second end of the fourth resistor R4 is electrically connected to the first end of the fifth resistor R5 , and the second end of the fifth resistor R5 is electrically connected to the second end of the second magnetic bead B2 .

[0072] In specific implementation, the sampling circuit 140 includes: a fourth resistor R4 and a fifth resistor R5. The fourth resistor R4 and the fifth resistor R5 are high-precision low-temperature drift sampling resistors, which can convert current signals into voltage signals, thereby converting the second filtered current into a sampling voltage.

[0073] In addition, if Figure 2 As shown, the first end of the fourth resistor R4 is also electrically connected to the IAP end of the digital-to-analog conversion chip, and the second end of the fifth resistor R5 is also electrically connected to the IAN end of the digital-to-analog conversion chip. In this way, after the sampling circuit 140 converts the second filtered current into a sampling voltage, the sampling voltage is input into the digital-to-analog conversion chip ADC.

[0074] Through the above solution, the sampling circuit 140 can convert the current signal into a voltage signal, thereby converting the second filtered current into a sampling voltage, so as to perform further filtering processing on the sampling voltage.

[0075] In some embodiments, Figure 2 As shown, the second filtering circuit 150 includes: a second resistor R2, a second capacitor C2, a third resistor R3 and a third capacitor C3.

[0076] The first end of the second resistor R2 is electrically connected to the first end of the fourth resistor R4, the second end of the second resistor R2 is electrically connected to the first end of the second capacitor C2, the second end of the second capacitor C2 is electrically connected to the second end of the fourth resistor R4 and the first end of the third capacitor C3, the second end of the third capacitor C3 is electrically connected to the first end of the third resistor R3, and the second end of the third resistor R3 is electrically connected to the second end of the fifth resistor R5.

[0077] In a specific implementation, the second filtering circuit 150 includes: a second resistor R2, a second capacitor C2, a third resistor R3 and a third capacitor C3.

[0078] The first end of the second resistor R2 is electrically connected to the first end of the first protection circuit D1, the second end of the first magnetic bead B1, and the first end of the fourth resistor R4. The second end of the second resistor R2 is electrically connected to the first end of the second capacitor C2 and the IAP end of the digital-to-analog conversion chip.

[0079] The first end of the second capacitor C2 is electrically connected to the second end of the second resistor R2 and the IAP end of the digital-to-analog conversion chip. The second end of the second capacitor C2 is electrically connected to the second end of the fourth resistor R4, the first end of the fifth resistor R5, the first end of the third capacitor C3 and grounded.

[0080] The first end of the third capacitor C3 is electrically connected to the second end of the second capacitor C2, the second end of the fourth resistor R4, and the first end of the fifth resistor R5 and grounded. The second end of the third capacitor C3 is electrically connected to the first end of the third resistor R3 and the IAN end of the digital-to-analog conversion chip.

[0081] The first end of the third resistor R3 is electrically connected to the second end of the third capacitor C3 and the IAN end of the digital-to-analog conversion chip. The second end of the third resistor R3 is electrically connected to the first end of the second protection circuit D2, the second end of the second magnetic bead B2, and the second end of the fifth resistor R5.

[0082] Through the above solution, based on the second filtering circuit 150, the sampled voltage can be further filtered, thereby ensuring that the circuit breaker can achieve high-precision current collection under the conduction interference induced by the radio frequency field.

[0083] For the convenience of description, the above circuit is described by dividing it into various modules according to its functions. Of course, when implementing the present disclosure, the functions of each module can be implemented in the same or multiple software and / or hardware.

[0084] Based on the same inventive concept, the present disclosure also provides a current acquisition filtering method, which is applied to a current acquisition filtering circuit 100; the current acquisition filtering circuit includes: a current transformer, a first filtering circuit, a suppression circuit, a sampling circuit, and a second filtering circuit; Figure 4 As shown, the method includes:

[0085] Step 201: a current transformer receives an initial input current and converts the initial input current into a target input current;

[0086] Step 202: a first filtering circuit receives the target input current sent by the current transformer, and performs filtering on the target input current to obtain a first filtered current of a preset frequency;

[0087] Step 203: the suppression circuit receives the first filtered current sent by the first filtering circuit, and performs filtering on the first filtered current to obtain a second filtered current;

[0088] Step 204, the sampling circuit receives the second filtered current sent by the suppression circuit, and converts the second filtered current into a sampling voltage;

[0089] Step 205: The second filtering circuit receives the sampled voltage sent by the sampling circuit, and filters the sampled voltage to obtain a target voltage.

[0090] During specific implementation, the current transformer converts the initial input current into the target input current, thereby converting the large current on the primary side into a small current on the secondary side. The first filter current is an RC filter circuit. By setting the resistance value and the capacitance value in the first filter circuit, the cut-off frequency can be set, so that interference signals of different frequencies can be filtered. The suppression circuit is resistive at high frequencies, and is used to suppress high-frequency signals and eliminate RF noise and radio frequency energy in the transmission line structure, suppress high-frequency noise and spike interference on the signal line and the sound source line, and has the ability to absorb electrostatic pulses, thereby reducing electromagnetic interference. The sampling circuit converts the second filtered current into a sampling voltage, thereby converting the small current on the secondary side into a voltage signal. The second filter circuit can further process the radio frequency signal, thereby ensuring that the circuit breaker can achieve high-precision current acquisition under the conducted interference induced by the radio frequency field.

[0091] Through the above embodiments, by setting the RC first filtering circuit in the current collection filtering circuit, the problem of realizing high-precision current collection under the conduction interference induced by the radio frequency field is solved, the anti-interference ability is strong, the circuit structure is simple and easy to implement, the manufacturing cost is low, the space occupied is small, and the cut-off frequency of the RC filter can be flexibly controlled by adjusting the resistance value of the first resistor R1 and the capacitance value of the first capacitor C1, and it can be used in multiple fields such as enhanced intelligent circuit breakers, smart meters, and smart energy units.

[0092] In some embodiments, the first filtering circuit includes: a first resistor and a first capacitor; step 202 includes:

[0093] Step 2021, the first filter circuit receives the target input current sent by the current transformer;

[0094] Step 2022: determining a cutoff frequency based on a filter function and according to the resistance value of the first resistor and the capacitance value of the first capacitor.

[0095]

[0096] Among them, f L is the cut-off frequency, R1 is the resistance value of the first resistor, and C1 is the capacitance value of the first capacitor;

[0097] Step 2023: filtering the current in the target input current that is greater than the cut-off frequency according to the cut-off frequency, the first filtered current of the preset frequency.

[0098] In a specific implementation, the cutoff frequency is determined according to the frequency of the interference signal, and the frequency of the interference signal is used as the cutoff frequency, so that the interference signal higher than the cutoff frequency can be filtered. The resistance value of the first resistor and the capacitance value of the first capacitor are determined according to the filter function and the cutoff frequency, the first resistor is set according to the determined resistance value of the first resistor, and the first capacitor is set according to the determined capacitance value of the first capacitor, so that the first filter circuit after setting can filter the interference signal higher than the cutoff frequency.

[0099] Through the above scheme, the filtering function can accurately reflect the relationship between the resistance value of the first resistor, the capacitance value of the first capacitor and the cut-off frequency. Therefore, by setting the resistance value of the first resistor and the capacitance value of the first capacitor, the cut-off frequency can be accurately set, thereby filtering interference signals higher than the cut-off frequency, thereby obtaining a first filter current of a preset frequency.

[0100] In some embodiments, the process of determining the filter function includes:

[0101] Step 2022A, determining the differential equation of the first filtering circuit,

[0102]

[0103] Wherein, R1 is the resistance value of the first resistor, C1 is the capacitance value of the first capacitor, u0 is the voltage value across the first capacitor, t is the time, u s is the input signal of the first filtering circuit.

[0104] Step 2022B: performing Laplace transform on the differential equation of the first filter circuit to obtain the Laplace transform of the output signal of the first filter circuit.

[0105]

[0106] Wherein, U0(S) is the Laplace transform of the output signal of the first filtering circuit, τ is the time constant, s is the complex frequency, and U S (S) is the Laplace transform of the output signal of the first filtering circuit, u 0θ is the signal value at the initial time including the phase angle θ, A is the amplitude of the input signal of the first filter circuit, and ω is the angular frequency of the input signal of the first filter circuit.

[0107] Step 2022C: performing an inverse Laplace transform on the Laplace transform output by the first filter circuit to obtain a voltage value across the first capacitor.

[0108]

[0109] Wherein, u0 is the voltage value across the first capacitor, is the transient component, is the steady-state component, and the amplitude ratio in the steady-state component is The phase difference in the steady-state component is

[0110] Step 2022D, the relationship between the cut-off angular frequency and the time constant is Substituting the amplitude ratio in the steady-state component, we get the target amplitude ratio

[0111] The relationship between the cutoff angular frequency and the time constant is expressed as Substituting the phase difference in the steady-state component, we get the target phase difference

[0112] Step 2022E: Based on the cut-off angular frequency, determine the corresponding relationship between the cut-off frequency and the resistance value of the first resistor and the capacitance value of the first capacitor, and use it as the filtering function.

[0113]

[0114] Among them, f L is the cut-off frequency.

[0115] In a specific implementation, the input signal of the first filter circuit is represented as u s =Asinωt, where A is the amplitude of the input signal of the first filtering circuit, and ω is the angular frequency of the input signal of the first filtering circuit.

[0116] The voltage value across the first capacitor is denoted as u0, and the voltage value across the first resistor is denoted as u R , the resistance value of the first resistor is represented by R1, the capacitance value of the first capacitor is represented by C1, the current flowing through the first resistor and the first capacitor is represented by i, and the time is represented by t. R =R1i, Determine the differential equation for the first filter circuit,

[0117]

[0118] Solve the differential equation of the first filter circuit. Use Laplace transform to substitute the time constant τ=R1C1 into the differential equation of the first filter circuit to obtain the Laplace transform of the output signal of the first filter circuit.

[0119]

[0120] Where U0(S) is the Laplace transform of the output signal of the first filter circuit, τ is the time constant, s is the complex frequency, and U S(S) is the Laplace transform of the output signal of the first filter circuit, u 0θ is the signal value at the initial time including the phase angle θ.

[0121] Performing Laplace inverse transformation on the Laplace transform of the output signal of the first filter circuit to obtain the voltage value across the first capacitor,

[0122]

[0123] Wherein, u0 is the voltage value across the first capacitor, is the transient component, is the steady-state component.

[0124] Among them, the transient component gradually approaches 0 as time t increases infinitely.

[0125] The steady-state component is expressed as Among them, the amplitude ratio in the steady-state component is The relationship between the amplitude and the frequency is also called the amplitude-frequency characteristic. The phase difference in the steady-state component is The relationship with angular frequency is also called phase-frequency characteristic. The amplitude ratio and phase difference reflect the change of amplitude and phase of the steady-state component of the RC network under the action of the sinusoidal signal. The amplitude ratio and phase difference are both functions of the angular frequency ω of the input sinusoidal signal. Based on the amplitude ratio and phase difference, the steady-state component can also be expressed as

[0126] The relationship between the cut-off angular frequency and the time constant is: Substituting the relationship into the amplitude ratio in the steady-state component, we can obtain the target amplitude ratio. The relation Substituting the phase difference in the steady-state component into the target phase difference

[0127] From the above target amplitude ratio and target phase difference, it can be seen that when the input frequency is much smaller than the cutoff frequency ω<<ω L When |A(ω)|≈1, When the input frequency is equal to the cut-off frequency ω=ω L hour, When the input frequency is much greater than the cutoff frequency ω>>ω L hour, When approaching infinity, |A(ω)|≈0, Therefore, for low-pass filter circuits, the higher the frequency, the greater the attenuation and the greater the phase shift. It is generally believed that when the input angular frequency is greater than the cutoff frequency, the attenuation is large.

[0128] Based on the cut-off angular frequency, the corresponding relationship between the cut-off frequency and the resistance value of the first resistor and the capacitance value of the first capacitor is determined and used as a filtering function.

[0129]

[0130] The conducted interference induced by the radio frequency field is mainly aimed at electrical and electronic equipment to the signal in the frequency range of 150kHz-80MHz, so the cut-off frequency f L Set at 100kHz, so that above f L The signal is filtered out by the first filter current composed of the first resistor and the first capacitor, thereby ensuring that the circuit breaker can achieve high-precision current collection under the conduction interference induced by the radio frequency field.

[0131] Specifically, Assuming R1=100Ω, we can obtain C1≈16nF, which means that signals above 100kHz can be filtered.

[0132] Through the above scheme, the filtering function can accurately reflect the relationship between the resistance value of the first resistor, the capacitance value of the first capacitor and the cut-off frequency. Therefore, by setting the resistance value of the first resistor and the capacitance value of the first capacitor, the cut-off frequency can be accurately set, thereby filtering interference signals higher than the cut-off frequency, thereby obtaining a first filter current of a preset frequency.

[0133] In some embodiments, the second filtering circuit includes: a second resistor, a second capacitor, a third resistor and a third capacitor. When the input signal is a high-frequency AC signal, the second capacitor C2 and the third capacitor C3 can be regarded as a short circuit. At this time, the signal received at the output end will be weaker than the input signal because part of the high-frequency signal is grounded through the capacitor, thus playing a filtering role.

[0134] By analyzing the principle of low-pass filtering through transfer function,

[0135]

[0136] Where H(S) is the transfer function, V0 is the output signal, V i is the input signal, j is the complex frequency, ω is the angular frequency of the input signal, R is the resistance value of the second resistor or the resistance value of the third resistor, and C is the capacitance value of the second capacitor or the capacitance value of the third capacitor.

[0137]

[0138] Then the expression of the transfer function is

[0139] Where H(S) is the transfer function, f is the input signal frequency, and f0 is the cutoff frequency.

[0140] After the RC parameters of the filter are set, the cutoff frequency f0 can be set. When the input signal frequency is much smaller than f0, the amplitude of H(S) is close to 1, that is, the input signal reaches the output without attenuation. When the input signal frequency is greater than f0, the amplitude of H(S) is less than 1, and the output signal is attenuated relative to the input signal. When the input signal frequency is equal to f0, the amplitude of the output signal is 0.707 times the input signal, and the signal frequency is just the bandwidth of the low-pass filter.

[0141] Through the above embodiments, by setting the RC first filtering circuit in the current collection filtering circuit, the problem of realizing high-precision current collection under the conduction interference induced by the radio frequency field is solved, the anti-interference ability is strong, the circuit structure is simple and easy to implement, the manufacturing cost is low, the space occupied is small, and the cut-off frequency of the RC filter can be flexibly controlled by adjusting the resistance value of the first resistor R1 and the capacitance value of the first capacitor C1, and it can be used in multiple fields such as enhanced intelligent circuit breakers, smart meters, and smart energy units.

[0142] In order to verify the effectiveness of the circuit design method for realizing high-precision current acquisition of a circuit breaker under the conducted interference induced by a radio frequency field proposed in the embodiment of the present disclosure, in an experimental environment, a radio frequency signal generator was used to test the current loop of the circuit breaker at a voltage level of 10V, an interference signal frequency range of 150kHz-80kHz, and a step size of 1%.

[0143] First, a 1.5A current is applied to the current loop. Figure 2 The first resistor R1 and the first capacitor C1 in the current collection and filtering circuit shown in the figure are removed and the test is carried out. Figure 5 and Figure 6 shown.

[0144] Figure 5 This is the first output waveform of the embodiment of the present disclosure without the first filtering circuit. Figure 6 The second output waveform of the embodiment of the present disclosure without the first filter circuit. Figure 5 As shown, in the current collection filter circuit without the first resistor R1 and the first capacitor C1, when the interference signal frequency is 5.5MHz, the top of the positive half cycle of the output waveform is slightly distorted and the amplitude changes. Figure 6 As shown, in the current collection filter circuit without the first resistor R1 and the first capacitor C1, when the interference signal frequency is 35 MHz, the output waveform is completely distorted.

[0145] The first resistor R1 and the first capacitor C1 are welded to the current collection filter circuit of the circuit breaker. Within the entire interference signal frequency range of 150kHz-80MHz, the waveform generated by the conducted interference induced by the radio frequency field is effectively filtered out, and the output waveform is not distorted, thereby achieving high-precision current collection.

[0146] Figure 7 : is the output waveform of the current acquisition filter circuit of the embodiment of the present disclosure. Figure 7 As shown, in the current collection and filtering circuit provided with the first resistor R1 and the first capacitor C1, when the interference signal frequency is 79 MHz, the output waveform is not distorted.

[0147] It should be noted that the method of the embodiment of the present disclosure can be performed by a single device, such as a computer or a server. The method of the present embodiment can also be applied in a distributed scenario and completed by multiple devices cooperating with each other. In the case of such a distributed scenario, one of the multiple devices can only perform one or more steps in the method of the embodiment of the present disclosure, and the multiple devices will interact with each other to complete the described method.

[0148] It should be noted that the above describes some embodiments of the present disclosure. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the above embodiments and still achieve the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0149] The method of the above embodiment is applied to the corresponding current acquisition filter circuit in any of the above embodiments, and has the beneficial effects of the corresponding circuit embodiment, which will not be described in detail here.

[0150] Based on the same inventive concept, corresponding to any of the above-mentioned embodiments and methods, the present disclosure also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the current acquisition and filtering method described in any of the above embodiments is implemented.

[0151] Figure 8 A more specific schematic diagram of the hardware structure of an electronic device provided in this embodiment is shown, and the device may include: a processor 1010, a memory 1020, an input / output interface 1030, a communication interface 1040, and a bus 1050. The processor 1010, the memory 1020, the input / output interface 1030, and the communication interface 1040 are connected to each other through the bus 1050 in the device.

[0152] The processor 1010 can be implemented by a general-purpose CPU (Central Processing Unit), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this specification.

[0153] The memory 1020 may be implemented in the form of ROM (Read Only Memory), RAM (Random Access Memory), static storage device, dynamic storage device, etc. The memory 1020 may store an operating system and other application programs. When the technical solutions provided in the embodiments of this specification are implemented by software or firmware, the relevant program codes are stored in the memory 1020 and are called and executed by the processor 1010.

[0154] The input / output interface 1030 is used to connect the input / output module to realize information input and output. The input / output module can be configured in the device as a component (not shown in the figure), or it can be externally connected to the device to provide corresponding functions. The input device may include a keyboard, a mouse, a touch screen, a microphone, various sensors, etc., and the output device may include a display, a speaker, a vibrator, an indicator light, etc.

[0155] The communication interface 1040 is used to connect a communication module (not shown in the figure) to realize communication interaction between the device and other devices. The communication module can realize communication through a wired mode (such as USB (Universal Serial Bus), network cable, etc.), or through a wireless mode (such as mobile network, WIFI (Wireless Fidelity), Bluetooth, etc.).

[0156] The bus 1050 includes a path that transmits information between the various components of the device (eg, the processor 1010, the memory 1020, the input / output interface 1030, and the communication interface 1040).

[0157] It should be noted that, although the above device only shows the processor 1010, the memory 1020, the input / output interface 1030, the communication interface 1040 and the bus 1050, in the specific implementation process, the device may also include other components necessary for normal operation. In addition, it can be understood by those skilled in the art that the above device may also only include the components necessary for implementing the embodiments of the present specification, and does not necessarily include all the components shown in the figure.

[0158] The electronic device of the above embodiment is used to implement the corresponding current acquisition and filtering method in any of the above embodiments, and has the beneficial effects of the corresponding method embodiment, which will not be described in detail here.

[0159] Based on the same inventive concept, corresponding to any of the above-mentioned embodiment methods, the present disclosure also provides a non-transitory computer-readable storage medium, wherein the non-transitory computer-readable storage medium stores computer instructions, and the computer instructions are used to enable the computer to execute the current acquisition and filtering method described in any of the above embodiments.

[0160] The computer-readable medium of this embodiment includes permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, read-only compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device.

[0161] The computer instructions stored in the storage medium of the above embodiment are used to enable the computer to execute the current acquisition and filtering method described in any of the above embodiments, and have the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0162] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present disclosure is limited to these examples. Based on the concept of the present disclosure, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present disclosure as described above, which are not provided in detail for the sake of simplicity.

[0163] In addition, to simplify the description and discussion, and in order not to make the embodiments of the present disclosure difficult to understand, the known power / ground connections to the integrated circuit (IC) chips and other components may or may not be shown in the provided figures. In addition, the device can be shown in the form of a block diagram to avoid making the embodiments of the present disclosure difficult to understand, and this also takes into account the fact that the details of the implementation of these block diagram devices are highly dependent on the platform on which the embodiments of the present disclosure will be implemented (that is, these details should be fully within the scope of understanding of those skilled in the art). Where specific details (e.g., circuits) are set forth to describe exemplary embodiments of the present disclosure, it is apparent to those skilled in the art that the embodiments of the present disclosure can be implemented without these specific details or with changes in these specific details. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0164] Although the present disclosure has been described in conjunction with specific embodiments of the present disclosure, many replacements, modifications and variations of these embodiments will be apparent to those skilled in the art from the foregoing description. For example, other memory architectures (e.g., dynamic RAM (DRAM)) may use the embodiments discussed.

[0165] The embodiments of the present disclosure are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the present disclosure. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present disclosure should be included in the scope of protection of the present disclosure.

Claims

1. A current collection filter circuit, characterized in that: include: A current transformer configured to receive an initial input current and convert the initial input current into a target input current; a first filtering circuit, electrically connected to the current transformer, configured to receive the target input current sent by the current transformer, and filter the target input current to obtain a first filtered current of a preset frequency; a suppression circuit, electrically connected to the first filter circuit, configured to receive the first filter current sent by the first filter circuit, and filter the first filter current to obtain a second filter current; a sampling circuit, electrically connected to the suppression circuit, configured to receive the second filtered current sent by the suppression circuit, and convert the second filtered current into a sampling voltage; The second filtering circuit is electrically connected to the sampling circuit, and is configured to receive the sampling voltage sent by the sampling circuit, and filter the sampling voltage to obtain a target voltage.

2. The circuit according to claim 1, characterized in that The first filtering circuit includes: a first resistor and a first capacitor; The first end of the first resistor is electrically connected to the first end of the current transformer, the second end of the first resistor is electrically connected to the first end of the first capacitor, and the second end of the first capacitor is electrically connected to the second end of the current transformer.

3. The circuit according to claim 2, characterized in that The suppression circuit comprises: a first magnetic bead and a second magnetic bead; The first end of the first magnetic bead is electrically connected to the first end of the first resistor, and the first end of the second magnetic bead is electrically connected to the second end of the first capacitor.

4. The circuit according to claim 3, characterized in that The current collection and filtering circuit further includes: a protection circuit; the protection circuit includes: a first protection circuit and a second protection circuit; The first protection circuit comprises: a first diode and a second diode, wherein an anode of the first diode and a cathode of the second diode are electrically connected to the second end of the first magnetic bead, and a cathode of the first diode is electrically connected to an anode of the second diode and is grounded; The second protection circuit includes: a third diode and a fourth diode, wherein the anode of the third diode and the cathode of the fourth diode are electrically connected to the second end of the second magnetic bead, and the cathode of the third diode is electrically connected to the anode of the fourth diode and is grounded.

5. The circuit according to claim 3, characterized in that The sampling circuit comprises: a fourth resistor and a fifth resistor; The first end of the fourth resistor is electrically connected to the second end of the first magnetic bead, the second end of the fourth resistor is electrically connected to the first end of the fifth resistor, and the second end of the fifth resistor is electrically connected to the second end of the second magnetic bead.

6. The circuit according to claim 5, characterized in that The second filtering circuit includes: a second resistor, a second capacitor, a third resistor and a third capacitor; The first end of the second resistor is electrically connected to the first end of the fourth resistor, the second end of the second resistor is electrically connected to the first end of the second capacitor, the second end of the second capacitor is electrically connected to the second end of the fourth resistor and the first end of the third capacitor, the second end of the third capacitor is electrically connected to the first end of the third resistor, and the second end of the third resistor is electrically connected to the second end of the fifth resistor.

7. A current collection and filtering method, characterized in that: The method is applied to a current acquisition filter circuit; The current collection and filtering circuit comprises: a current transformer, a first filtering circuit, a suppression circuit, a sampling circuit and a second filtering circuit; the method comprises: The current transformer receives an initial input current and converts the initial input current into a target input current; The first filtering circuit receives the target input current sent by the current transformer, and performs filtering on the target input current to obtain a first filtered current with a preset frequency; The suppression circuit receives the first filter current sent by the first filter circuit, and performs filtering on the first filter current to obtain a second filter current; The sampling circuit receives the second filtered current sent by the suppression circuit and converts the second filtered current into a sampling voltage; The second filtering circuit receives the sampled voltage sent by the sampling circuit, and filters the sampled voltage to obtain a target voltage.

8. The method according to claim 7, characterized in that The first filtering circuit includes: a first resistor and a first capacitor; The first filtering circuit receives the target input current sent by the current transformer, and performs filtering on the target input current to obtain a first filtered current of a preset frequency, including: The first filter circuit receives the target input current sent by the current transformer; Based on the filter function, a cutoff frequency is determined according to the resistance value of the first resistor and the capacitance value of the first capacitor, Among them, f L is the cut-off frequency, R1 is the resistance value of the first resistor, and C1 is the capacitance value of the first capacitor; According to the cut-off frequency, a current in the target input current that is greater than the cut-off frequency is filtered, and a first filtered current with the preset frequency is obtained.

9. The method according to claim 8, characterized in that The process of determining the filtering function includes: determining a differential equation for the first filtering circuit, Wherein, R1 is the resistance value of the first resistor, C1 is the capacitance value of the first capacitor, u0 is the voltage value across the first capacitor, t is the time, u s is the input signal of the first filtering circuit; performing Laplace transform on the differential equation of the first filter circuit to obtain a Laplace transform of an output signal of the first filter circuit, Wherein, U0(S) is the Laplace transform of the output signal of the first filtering circuit, τ is the time constant, s is the complex frequency, and U S (S) is the Laplace transform of the output signal of the first filtering circuit, u 0θ is the signal value at the initial moment including the phase angle θ, A is the amplitude of the input signal of the first filter circuit, and ω is the angular frequency of the input signal of the first filter circuit; Performing an inverse Laplace transform on the Laplace transform output by the first filter circuit to obtain a voltage value across the first capacitor, Wherein, u0 is the voltage value across the first capacitor, is the transient component, is the steady-state component, and the amplitude ratio in the steady-state component is The phase difference in the steady-state component is The relationship between the cutoff angular frequency and the time constant is expressed as Substituting the amplitude ratio in the steady-state component, we get the target amplitude ratio The relationship between the cutoff angular frequency and the time constant is expressed as Substituting the phase difference in the steady-state component, we get the target phase difference Based on the cut-off angular frequency, a corresponding relationship between the cut-off frequency and the resistance value of the first resistor and the capacitance value of the first capacitor is determined and used as the filtering function. Among them, f L is the cut-off frequency.

10. An electronic device, characterized in that: The method comprises a memory, a processor and a computer program stored in the memory and running on the processor, wherein when the processor executes the program, the method according to any one of claims 7 to 9 is implemented.

Images