An adaptive filtering device for electromagnetic noise amplitude detection and its working method

Abstract

The present application discloses an adaptive filtering device for detecting the amplitude of electromagnetic noise and its working method. The detection circuit is composed of a sampling resistor R and a capacitor C connected in series and then connected to an optocoupler circuit. A diode is anti-parallel connected to the primary side of the optocoupler to protect the optocoupler and a digital signal controller is connected. The detection circuit is implemented by an RC circuit and a voltage transformer. The electromagnetic noise signal in the power loop is coupled through the voltage transformer, conditioned and amplified by an operational amplifier, and then sent to the AD sampling pin of the controller. The controller compares the detected noise amplitude with the set threshold and controls the on / off of R y1 -R y6 . The device can also detect the amplitude of the electromagnetic noise in the power loop in real time through the optocoupler circuit and the digital signal controller, and actively control the parameters of the filtering device according to the noise amplitude. This enables the device to not only effectively reduce electromagnetic noise, but also save energy, reduce the reactive power content, reduce the leakage current, and thus avoid the electric shock risk caused by poor grounding.

Description

Technical Field

[0001] The present application belongs to the field of electromagnetic filtering technology, and in particular relates to an adaptive filtering device for electromagnetic noise amplitude detection and a working method thereof. Background Art

[0002] With the development of power electronics technology and the popularization of switching power supplies, electromagnetic interference in power systems has become more and more frequent, and filters are the most effective means to solve electromagnetic interference. At present, the general circuit structure of the filter is a frequency selection network composed of inductors, X capacitors and Y capacitors, which are connected in series in the power circuit. Due to the existence of magnetic loss and copper loss, the inductor will consume a certain amount of energy, resulting in a decrease in system efficiency; due to the existence of X capacitors, the phase of the voltage naturally lags behind the current, resulting in an increase in the reactive power of the system and facing the problem of fines from the power grid; due to the existence of Y capacitors, the system generates leakage current, and there is a risk of electric shock in the case of poor grounding. Summary of the invention

[0003] The embodiment of the present application provides an adaptive filtering device for electromagnetic noise amplitude detection and a working method thereof. The present invention is implemented through a circuit through an electromagnetic noise detection method and integrated into an adaptive filtering device. The device can control the parameters of the filter according to the electromagnetic noise amplitude detected in real time, thereby effectively reducing the energy consumption and reactive content of the system in long-term operation and avoiding possible risks of electric shock.

[0004] In a first aspect, the present invention provides an adaptive filtering device for electromagnetic noise amplitude detection, wherein an inductor L1 is provided between a live line L and a neutral line N, and a user load is connected after being connected in series with the inductor L1, and a first sampling resistor Ry1 is connected in series on the live line L and at the input end and the output end of the inductor L1; and a second sampling resistor Ry2 is connected in series on the neutral line N and at the input end and the output end of the inductor L1;

[0005] A detection circuit is connected in parallel upstream of the inductor L1 and between the live line L and the neutral line N, two first Y-type filter capacitors CY1 and second Y-type filter capacitors CY2 connected in series, and a first X-type filter capacitor Cx1, a third sampling resistor Ry3 is connected in series with the third capacitor Cx1, and a second X-type filter capacitor Cx2 is further provided between the live line L and the neutral line N downstream of the inductor L1, and a fourth sampling resistor Ry4 is connected in series with the second X-type filter capacitor Cx2; after the first Y-type filter capacitor CY1 and the second Y-type filter capacitor CY2 take power, they are connected in series with the fifth sampling resistor Ry5 and then connected to the ground line PE, and the second X-type filter capacitor Cx2 is connected in series with the fourth sampling resistor Ry4, which takes power in series with the sixth sampling resistor Ry6 and then connected to the ground line PE.

[0006] Preferably, the user load is a DC device or an AC device.

[0007] Preferably, the live wire L terminal is connected in series with the detection circuit and then grounded, and a detection circuit is connected in series between the neutral wire N and the ground wire PE.

[0008] Preferably, when the user load is a DC device, the device is connected in series between the DC device or the DC grid, and the first sampling resistor Ry1, the second sampling resistor Ry2, the third sampling resistor Ry3, the fourth sampling resistor Ry4, the fifth sampling resistor Ry5 and the sixth sampling resistor Ry6 are DC contactors or power transistors.

[0009] Preferably, the detection circuit is a sampling resistor R and a capacitor C connected in series, which are then connected to an optocoupler circuit, an anti-parallel diode is connected on the primary side of the optocoupler to protect the optocoupler and the detection circuit is connected to a digital signal controller.

[0010] Preferably, the detection circuit is implemented by using RC+voltage transformer. The electromagnetic noise signal in the power circuit is coupled through the voltage transformer and amplified by the operational amplifier and then sent to the AD sampling pin of the controller. The controller compares the detected noise amplitude with the set threshold and controls the on and off of RY1-RY6 according to the calculation result.

[0011] On the second aspect, the present application provides a working method of an adaptive filtering device for electromagnetic noise amplitude detection, which is connected in series between the user load and the AC power grid. In the initial state, RY1 and RY2 are closed, RY3, RY4, RY5 and RY6 are disconnected, and the detection circuit detects the noise amplitude of L to PE and N to PE in real time. When the electromagnetic noise amplitude in the power circuit exceeds the set limit, the optocoupler in the detection circuit is turned on and transmits a signal to the controller. The controller controls the on and off of RY1-RY6 through the feedback signal of the detection circuit.

[0012] In a third aspect, the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method described in the second aspect is implemented.

[0013] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0014] 1) Electromagnetic noise filtering; reducing energy consumption and reactive power content; reducing leakage current and avoiding the risk of electric shock caused by poor grounding.

[0015] 2) It has the function of real-time detection of the electromagnetic noise amplitude of the power circuit and active control of the filter device parameters according to the noise amplitude. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 A principle block diagram of a single-phase user load provided in an embodiment of the present application;

[0018] Figure 2 A schematic diagram of a π-type filter circuit provided in an embodiment of the present application;

[0019] Figure 3 The principle of the filter provided in one embodiment of the present application Figure 1 ;

[0020] Figure 4 A schematic diagram of a noise threshold detection circuit provided in an embodiment of the present application;

[0021] Figure 5 A workflow diagram provided for an embodiment of the present application;

[0022] Figure 6 A filter schematic diagram provided for another embodiment of the present application;

[0023] Figure 7 Principle of the detection circuit provided for another embodiment of the present application Figure 2 . DETAILED DESCRIPTION

[0024] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0025] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0026] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0027] As used in the specification and appended claims of this application, the term "if" can be interpreted as "when" or "uponce" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "uponce it is determined" or "in response to determining" or "uponce [described condition or event] is detected" or "in response to detecting [described condition or event]", depending on the context.

[0028] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0029] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0030] In the prior art, Figure 1 This is a principle block diagram of a single-phase AC device. In order to meet the input EMI requirements, the input port is equipped with an EMI filter circuit. The EMI filter circuit is composed of X capacitors, Y capacitors and common mode inductors.

[0031] Figure 2 This is a schematic diagram of a commonly used single-phase first-stage π-type EMI filter circuit. CY1-CY4 are Y filter capacitors, which together with the common-mode inductor of inductor L1 form a first-stage common-mode noise filter; CX1 and CX2 are X filter capacitors, which together with the differential-mode component of inductor L1 form a first-stage differential-mode noise filter.

[0032] For better expression, the Y filter capacitor and the X filter capacitor are numbered and named, see a possible embodiment.

[0033] In one possible implementation, Figure 3 As shown,

[0034] This embodiment provides an adaptive filtering device for electromagnetic noise amplitude detection, wherein an inductor L1 is provided between a live line L and a neutral line N, and a user load is connected after being connected in series with the inductor L1, and a first sampling resistor Ry1 is connected in series on the live line L and at the input end and the output end of the inductor L1; and a second sampling resistor Ry2 is connected in series on the neutral line N and at the input end and the output end of the inductor L1;

[0035] A detection circuit is connected in parallel upstream of the inductor L1 and between the live line L and the neutral line N, two first Y-type filter capacitors Cy1 and second Y-type filter capacitors Cy2 connected in series, and a first X-type filter capacitor Cx1, a third sampling resistor Ry3 is connected in series with the third capacitor Cx1, and a second X-type filter capacitor Cx2 is also provided between the live line L and the neutral line N downstream of the inductor L1, and a fourth sampling resistor Ry4 is connected in series with the second X-type filter capacitor Cx2; after the first Y-type filter capacitor CY1 and the second Y-type filter capacitor CY2 take power, one path is connected in series with the fifth sampling resistor Ry5 and then connected to the ground line PE, and the second X-type filter capacitor Cx2 is connected in series with the fourth sampling resistor Ry4, which takes power in series with the sixth sampling resistor Ry6 and then connected to the ground line PE.

[0036] The user load is a DC device or an AC device.

[0037] The live wire L terminal is connected in series with the detection circuit and then grounded, and a detection circuit is connected in series between the neutral wire N and the ground wire PE.

[0038] When the user load is a DC device, the device is connected in series between the DC device or the DC grid, and the first sampling resistor Ry1, the second sampling resistor Ry2, the third sampling resistor Ry3, the fourth sampling resistor Ry4, the fifth sampling resistor Ry5 and the sixth sampling resistor Ry6 are DC contactors or power transistors.

[0039] The detection circuit is a sampling resistor R connected in series with a capacitor C, which is then connected to an optocoupler circuit. An anti-parallel diode is connected to the primary side of the optocoupler to protect the optocoupler and is connected to a digital signal controller.

[0040] The detection circuit is implemented by an RC circuit and a voltage transformer. The electromagnetic noise signal in the power circuit is coupled by the voltage transformer and amplified by the operational amplifier before being sent to the AD sampling pin of the controller. The controller compares the detected noise amplitude with the set threshold and controls the on and off of Ry1-Ry6 according to the calculation result.

[0041] The present embodiment provides a working method of an adaptive filtering device for electromagnetic noise amplitude detection, which is connected in series between a user load and an AC power grid. In an initial state, Ry1 and Ry2 are closed, and Ry3, Ry4, Ry5, and Ry6 are disconnected. The detection circuit detects the noise amplitudes of L to PE and N to PE in real time. When the electromagnetic noise amplitude in the power circuit exceeds a set limit, the optocoupler in the detection circuit is turned on and transmits a signal to the controller. The controller controls the on and off of Ry1-Ry6 through the feedback signal of the detection circuit.

[0042] The electromagnetic noise amplitude detection circuit is implemented using RC+ optocoupler, such as Figure 4 The impedance of the circuit is hardly affected by frequency changes, and a safety design with reinforced insulation from dangerous circuits is achieved.

[0043] The function of C is to isolate DC from AC, R is the sampling resistor, and the input of the optocoupler is the voltage across R. Considering that the voltage across R is an AC component, an anti-parallel diode is connected on the primary side of the optocoupler to protect the optocoupler.

[0044] When the amplitude of electromagnetic noise in the power circuit exceeds the set limit, the optocoupler in the detection circuit is turned on and transmits a signal to the controller. The controller controls the on and off of RY1-RY6 through the feedback signal of the detection circuit, thereby achieving the functions of filtering, reducing energy consumption, reactive power and leakage current;

[0045] like Figure 5 As shown, when the system is working normally, the active filter is connected in series between the user load and the AC power grid. In the initial state, Ry1 and Ry2 are closed, Ry3, Ry4, Ry5 and Ry6 are disconnected, and the detection circuit detects the noise amplitude of L to PE and N to PE in real time.

[0046] During the whole operation process, the single chip microcomputer uses concurrent operation.

[0047] Objective: Use a single-chip microcomputer to detect electromagnetic noise thresholds and automatically adjust filter parameters based on the detection results. Implementation steps:

[0048] Hardware design:

[0049] Design circuit diagram, including inductor, sampling resistor, capacitor, optocoupler circuit and microcontroller.

[0050] The sampling resistor and capacitor are connected in series, connected to the optocoupler circuit, and then connected to the ADC (analog-to-digital converter) input of the microcontroller.

[0051] MCU Programming:

[0052] Initialize the ADC module of the microcontroller and set the appropriate sampling frequency and resolution.

[0053] Initialize the GPIO (general purpose input and output) module of the microcontroller to control the on and off of the filter device.

[0054] Data collection:

[0055] The voltage value of the noise signal is collected through the ADC module.

[0056] The collected voltage value is converted into noise amplitude.

[0057] Noise amplitude detection: Set a noise amplitude threshold, such as 5 V. Compare the collected noise amplitude with the threshold.

[0058] Filter parameter adjustment: If the noise amplitude exceeds the threshold, the filter device (such as a relay or power transistor) is controlled to turn on and off through GPIO to reduce the noise.

[0059] If the noise amplitude is below the threshold, the current state of the filter device is maintained.

[0060] Real-time monitoring and adjustment: The noise threshold is continuously collected in a loop, and the filter parameters are adjusted according to the detection results. Timed collection and adjustment can be achieved through timer interrupts.

[0061] Debugging and optimization: Use debugging tools (such as the serial port debugging assistant) to view the working status of the MCU and the collected data. Optimize the algorithm and hardware design based on the debugging results to improve the stability and accuracy of the system.

[0062] 2. Sorting algorithm optimization: Quick Sort

[0063] Optimize the quick sort algorithm to improve sorting efficiency and reduce the time complexity in the worst case

[0064] Implementation steps: Select the quick sort algorithm because its average time complexity is O(n logn). The three-number middle method: Modify the quick sort algorithm and use the three-number middle method to select the benchmark to reduce the worst-case time complexity. Tail recursion optimization: Change the recursive part of the quick sort to tail recursion to reduce the overhead of recursive calls. Small array switching: For small arrays, use insertion sort instead of quick sort to improve the efficiency of small array sorting. Parallel processing: Implement a parallel version of quick sort on a single-chip microcomputer and use multi-core processors to increase processing speed.

[0065] In another possible implementation,

[0066] like Figure 6 As shown, it can be applied in DC systems, where the active filter is connected in series between the DC device and the DC grid. Figure 6 Ry1-Ry6 in the circuit are replaced with DC contactors or power transistors.

[0067] like Figure 7 As shown, the detection circuit can also be implemented by using RC+voltage transformer, which also has the function of resistance stability and reinforced insulation between dangerous circuits. The function of C is to block DC and pass AC, R is a sampling resistor, and the input of the voltage transformer is the voltage across R.

[0068] The electromagnetic noise signal in the power circuit is coupled through the voltage transformer and amplified by the operational amplifier before being sent to the AD sampling pin of the controller. The controller compares the detected noise amplitude with the set threshold value and controls the on and off of Ry1-Ry6 according to the calculation result, thereby achieving the functions of filtering, reducing energy consumption, reactive power and leakage current.

[0069] This embodiment provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method described above is implemented.

[0070] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0071] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0072] In the embodiments provided in the present application, it should be understood that the disclosed devices / network equipment and methods can be implemented in other ways. For example, the device / network equipment embodiments described above are merely schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0073] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0074] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. An adaptive filtering device for electromagnetic noise amplitude detection, characterized in that: An inductor L1 is provided between the live wire L and the neutral wire N. After being connected in series with the inductor L1, the user load is connected. A first sampling resistor R is connected in parallel on the live wire L and at the input and output ends of the inductor L1. Y1 A second sampling resistor R is connected in parallel on the zero line N and at the input and output ends of the inductor L1. Y2 ; A detection circuit and two first Y-type filter capacitors C connected in series are connected in parallel upstream of the inductor L1 and between the live wire L and the ground wire PE. Y1 and the second Y-type filter capacitor C Y2 And the first X-type filter capacitor C X1 , and the first X-type filter capacitor C X1 A third sampling resistor R is connected in series Y3 A second X-type filter capacitor C is provided between the live line L and the neutral line N downstream of the inductor L1. X2 , two third Y-type filter capacitors C connected in series Y3 , the fourth Y-type filter capacitor C Y4 ; and with the second X-type filter capacitor C X2 A fourth sampling resistor R is connected in series Y4 ; In the first Y-type filter capacitor C Y1 and the second Y-type filter capacitor C Y2 After taking power, the fifth sampling resistor R Y5 Connect the ground wire PE in series, the second X-type filter capacitor C X2 A fourth sampling resistor R is connected in series Y4 ; The third Y-type filter capacitor C Y3 and the fourth Y-type filter capacitor C Y4 Connect them in series and take a path between the two and the sixth sampling resistor R Y6 Connect in series to ground wire PE; first sampling resistor R Y1 , the second sampling resistor R Y2 , the third sampling resistor R Y3 , the fourth sampling resistor R Y4 , the fifth sampling resistor R Y5 and the sixth sampling resistor R Y6 It is a contactor or a power transistor.

2. The adaptive filtering device for electromagnetic noise amplitude detection according to claim 1, characterized in that: The user load is a DC device or an AC device.

3. The adaptive filtering device for electromagnetic noise amplitude detection according to claim 1, characterized in that: The live wire L terminal is connected in series with the detection circuit and then grounded, and a detection circuit is connected in series between the neutral wire N and the ground wire PE.

4. The adaptive filtering device for electromagnetic noise amplitude detection according to claim 3, characterized in that: The detection circuit is a sampling resistor R and a capacitor C connected in series, which are connected to an optocoupler circuit, an anti-parallel diode is connected on the primary side of the optocoupler to protect the optocoupler and is connected to a digital signal controller.

5. The adaptive filtering device for electromagnetic noise amplitude detection according to claim 4, characterized in that: The detection circuit is implemented by an RC circuit and a voltage transformer. The electromagnetic noise signal in the power circuit is coupled by a voltage transformer and amplified by an operational amplifier before being sent to the AD sampling pin of the controller. The controller compares the detected noise amplitude with the set threshold and controls R according to the calculation result. Y1 -R Y6 The on and off.

6. A working method of an adaptive filtering device for electromagnetic noise amplitude detection according to any one of claims 1 to 5, characterized in that: Connected in series between the user load and the AC power grid, in the initial state, R Y1 and R Y2 Closed, R Y3 , R Y4 , R Y5 and R Y6 The detection circuit detects the noise amplitude of L to PE and N to PE in real time; when the electromagnetic noise amplitude in the power circuit exceeds the set limit, the optocoupler in the detection circuit is turned on and transmits a signal to the controller, and the controller controls R through the feedback signal of the detection circuit. Y1 -R Y6 The on and off.

7. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method according to claim 6 is implemented.

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