Common mode capacitor and its use in emc filters

Abstract

The application belongs to the technical field of capacitors, and discloses a common-mode capacitor, which comprises a first electrode A, a second electrode B, a first shielding electrode G1 and a second shielding electrode G2; a positive pole of an input signal is connected with the first electrode A, a negative pole of the input signal is connected with the second electrode B, the first shielding electrode G1 is connected with the second shielding electrode G2, and a connecting point of the first shielding electrode G1 and the second shielding electrode G2 is connected to a ground GND; capacitors are respectively connected in series between the first electrode A and the first shielding electrode G1 and between the second electrode B and the second shielding electrode G2, so that a common-mode filtering path is formed; when a common-mode interference signal appears, voltage change caused by the common-mode interference signal is coupled through the capacitors between the first electrode A and the first shielding electrode G1 and between the second electrode B and the second shielding electrode G2, so that the formed current flows to the ground GND, the influence of the interference signal on a circuit is reduced, and common-mode interference is effectively inhibited.

Description

Technical Field

[0001] This invention relates to the field of capacitor technology, and in particular to a common-mode capacitor and its application in EMC filters. Background Technology

[0002] In electromagnetic compatibility (EMC) issues, noise and interference control is crucial. We typically discuss common-mode noise and common-mode interference, a type of interference that occurs between two lines in a circuit (usually power or signal lines) and a reference ground (usually ground). A common solution to suppress this interference is the use of common-mode inductors. Common-mode inductors provide high impedance to common-mode interference while having less impact on differential-mode signals, making them a common choice for power inputs and signal input / output terminals.

[0003] However, common-mode inductors also have their limitations. Because they are based on ferrite cores, their impedance characteristics vary greatly under different current-carrying conditions, especially in the high-frequency region (e.g., tens of MHz). When the inductor is under rated current conditions, its noise suppression effect may be greatly reduced because the core enters a saturation state under high current, which leads to a decrease in the inductor's effectiveness.

[0004] These limitations indicate that relying solely on common-mode inductors is insufficient to meet increasingly stringent electromagnetic compatibility requirements for EMC filters.

[0005] Therefore, there is an urgent need for a common-mode capacitor and its application in EMC filters. Summary of the Invention

[0006] This invention provides a common-mode capacitor and its application in EMC filters to solve the aforementioned problems existing in the prior art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A common-mode capacitor includes: a first electrode A, a second electrode B, a first shielding electrode G1, and a second shielding electrode G2;

[0009] The positive terminal of the input signal is connected to the first electrode A, the negative terminal of the input signal is connected to the second electrode B, the first shielding electrode G1 is connected to the second shielding electrode G2, and the connection point of the first shielding electrode G1 and the second shielding electrode G2 is connected to ground GND.

[0010] A capacitor is connected in series between the first electrode A and the first shielding electrode G1, and between the second electrode B and the second shielding electrode G2, to form a common-mode filtering path.

[0011] When a common-mode interference signal appears, the voltage change caused by the common-mode interference signal is coupled to ground GND through the capacitive coupling effect between the first electrode A and the first shielding electrode G1 and the second electrode B and the second shielding electrode G2, thereby reducing the impact of the interference signal on the circuit and effectively suppressing common-mode interference.

[0012] When a differential mode signal is generated between the first electrode A and the second electrode B, the differential mode signal is transmitted through the main path of the circuit, while high-frequency differential mode noise is bypassed through the capacitor between the first electrode A and the second electrode B, without generating current to ground GND, thereby ensuring the integrity of signal transmission and reducing the impact of differential mode noise.

[0013] When a differential mode signal is generated between the first electrode A and the second electrode B, no current is generated at the guide ground GND, and the differential mode signal is transmitted normally through the capacitor.

[0014] Wherein, at least one dielectric layer is included between the first electrode A and the second electrode B, and the dielectric of the dielectric layer provides the required capacitance value and isolates the first electrode A and the second electrode B;

[0015] The first shielding electrode G1 and the second shielding electrode G2 have the same geometry and size to ensure uniform current distribution under common-mode interference.

[0016] The first electrode A and the second electrode B are connected by a dielectric stack layer, which is stacked in a corresponding order and thickness to filter out or reduce common-mode interference signals.

[0017] The dielectric stack layer includes: a first dielectric layer, which includes a first zirconium oxide layer and a first zirconium silicon oxide layer; a second zirconium oxide layer disposed between the first zirconium oxide layer and the first zirconium silicon oxide layer; and a silicon oxide layer disposed between the first zirconium oxide layer and the second zirconium oxide layer.

[0018] One application of a common-mode capacitor in an EMC filter, wherein the EMC filter includes: a common-mode capacitor, a differential-mode capacitor, and a filter control module;

[0019] The input terminal of the common-mode capacitor is electrically connected to the input terminal of the power supply line, and the output terminal is electrically connected to the input terminal of the load device; the input terminal of the differential-mode capacitor is electrically connected to the output terminal of the common-mode capacitor, and the output terminal is electrically connected to the input terminal of the load device; the control signal input terminal of the filter control module is connected to the control signal output terminals of the common-mode capacitor and the differential-mode capacitor; the filter characteristic adjustment signal output terminal of the filter control module is connected to the adjustment terminal of the common-mode capacitor; the filter control module obtains the filter effect feedback signal through the filter characteristic detection circuit.

[0020] Among them, the common-mode capacitor is used to provide high-frequency common-mode noise filtering function. By selecting the corresponding capacitance value, noise signals in a specific frequency range can be suppressed.

[0021] The filter control module includes a microprocessor and a digital-to-analog converter.

[0022] The microprocessor is used to calculate the filter characteristic adjustment signal based on the filter effect feedback signal, and convert the filter characteristic adjustment signal into an analog signal through a digital-to-analog converter to adjust the capacitance value of the common-mode capacitor, thereby realizing the dynamic adjustment of the filter to adapt to different noise environments and ensure that the filter has high-frequency filtering characteristics.

[0023] The calculation of the filter characteristic adjustment signal based on the filter effect feedback signal includes:

[0024] The microprocessor receives a filtering effect feedback signal from the filtering circuit, which indicates the current performance and operating status of the filtering circuit.

[0025] Based on a preset signal analysis template, the microprocessor analyzes the received filtering effect feedback signal to determine the current performance indicators of the filtering circuit. The current performance indicators include the signal amplitude, frequency, phase and noise level.

[0026] Based on the analysis results, the microprocessor evaluates the performance of the filter circuit and determines whether adjustments are needed to ensure that the filtering effect meets the predetermined performance standards.

[0027] If adjustments are needed, the microprocessor calculates a filter characteristic adjustment signal based on the analysis results of the filter effect feedback signal and the preset adjustment algorithm. This filter characteristic adjustment signal aims to optimize the performance of the filter circuit to improve the filter effect.

[0028] The microprocessor converts the calculated filter characteristic adjustment signal from digital form to analog signal through a built-in or external digital-to-analog converter;

[0029] The converted analog filter characteristic adjustment signal output is used to adjust the capacitance value of the common-mode capacitor;

[0030] The common-mode capacitor that receives the analog filter characteristic adjustment signal adjusts its corresponding capacitance value according to the signal to change the characteristics of the filter circuit, thereby optimizing and controlling the filtering effect.

[0031] The filter control module obtains the filter effect feedback signal through the filter characteristic detection circuit, including:

[0032] The output signal of the filter circuit is monitored and analyzed in real time by the filter characteristic detection circuit to determine the current filtering effect;

[0033] Feedback signals about the filtering effect are obtained from the filter characteristic detection circuit. These feedback signals include key information about the performance of the filter circuit, such as parameters like filter frequency, amplitude change, and phase difference.

[0034] Based on the feedback signal, the filter control module is dynamically adjusted to optimize the filtering effect. This dynamic adjustment includes changing the filter's cutoff frequency, gain, or phase characteristics.

[0035] When the filtering effect detected by the filtering characteristic detection circuit reaches the preset standard or optimization target, the current setting is automatically maintained through the feedback mechanism to ensure the stability and reliability of the filtering effect.

[0036] The output signal of the filter circuit is monitored and analyzed in real time through a filter characteristic detection circuit, including:

[0037] The filter characteristic detection circuit determines the frequency characteristics of the filter circuit in real time by measuring the frequency response of the output signal;

[0038] The filter characteristic detection circuit includes the filter circuit input and output interfaces to obtain the input and output signals of the filter circuit;

[0039] It also includes a data analysis module, which is used to analyze the characteristics of the output signal of the filter circuit and provide real-time monitoring results;

[0040] By detecting the filtering characteristics of the output signal of the filtering circuit, abnormalities or changes generated by the circuit can be identified, enabling real-time monitoring and analysis of the filtering circuit performance.

[0041] Compared with the prior art, the present invention has the following advantages:

[0042] A common-mode capacitor includes: a first electrode A, a second electrode B, a first shielding electrode G1, and a second shielding electrode G2; the positive terminal of the input signal is connected to the first electrode A, the negative terminal of the input signal is connected to the second electrode B, the first shielding electrode G1 is connected to the second shielding electrode G2, and the connection point of the first shielding electrode G1 and the second shielding electrode G2 is connected to ground GND; capacitors are connected in series between the first electrode A and the first shielding electrode G1, and between the second electrode B and the second shielding electrode G2, respectively, thereby forming a common-mode filtering path; when a common-mode interference signal occurs, the voltage change caused by the common-mode interference signal is coupled to ground GND through the capacitive coupling effect between the first electrode A and the first shielding electrode G1, and between the second electrode B and the second shielding electrode G2, thereby reducing the influence of the interference signal on the circuit and effectively suppressing common-mode interference.

[0043] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention.

[0044] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0045] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0046] Figure 1 This is a structural diagram of a common-mode capacitor in an embodiment of the present invention;

[0047] Figure 2 This is a circuit diagram of a common-mode capacitor in an embodiment of the present invention. Detailed Implementation

[0048] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0049] This invention provides a common-mode capacitor, comprising: a first electrode A, a second electrode B, a first shielding electrode G1, and a second shielding electrode G2;

[0050] The positive terminal of the input signal is connected to the first electrode A, the negative terminal of the input signal is connected to the second electrode B, the first shielding electrode G1 is connected to the second shielding electrode G2, and the connection point of the first shielding electrode G1 and the second shielding electrode G2 is connected to ground GND.

[0051] A capacitor is connected in series between the first electrode A and the first shielding electrode G1, and between the second electrode B and the second shielding electrode G2, to form a common-mode filtering path.

[0052] When a common-mode interference signal appears, the voltage change caused by the common-mode interference signal is coupled to ground GND through the capacitive coupling effect between the first electrode A and the first shielding electrode G1 and the second electrode B and the second shielding electrode G2, thereby reducing the impact of the interference signal on the circuit and effectively suppressing common-mode interference.

[0053] The working principle of the above technical solution is as follows: Figure 2 As shown, the positive terminal of the input signal is connected to the first electrode A, the negative terminal of the input signal is connected to the second electrode B, the first shielding electrode G1 is connected to the second shielding electrode G2, and the connection point of the first shielding electrode G1 and the second shielding electrode G2 is connected to ground GND; capacitors are connected in series between the first electrode A and the first shielding electrode G1 and between the second electrode B and the second shielding electrode G2, thereby forming a common-mode filtering path.

[0054] The first electrode A and the second electrode B are connected to the positive and negative terminals of the input signal, respectively. The first shielding electrode G1 and the second shielding electrode G2 are located close to these two electrodes. They form a capacitive coupling effect through their internal structure. When a common-mode interference signal occurs, it generates the same voltage change on the first electrode A and the second electrode B. This change, through the capacitive coupling between the electrodes and the shielding electrodes, causes current to flow from G1 and G2 to the ground point GND, reducing the impact of the interference signal on the circuit and effectively suppressing common-mode interference. Simultaneously, since the first electrode A and the second electrode B are not directly connected but rather through a path formed by two capacitors in series, this structure also provides differential-mode filtering functionality.

[0055] The first electrode A and the second electrode B are not directly connected, but are connected in series with two capacitors, so the first electrode A and the second electrode B are open circuits; the first shielding electrode G1 and the second shielding electrode G2 are directly connected together, and there is a capacitor between the first electrode A and G1 / G2, and there is also a capacitor of the same size between the second electrode B and G1 / G2.

[0056] In this system, current is formed between the first electrode A and the first shielding electrode G1, and between the second electrode B and the second shielding electrode G2, through capacitive coupling. This current flows to ground GND to process common-mode interference signals. The capacitive coupling effect is caused by voltage changes induced by the common-mode interference signals, thus achieving effective shielding and processing of these signals. Ground GND provides a low-impedance path, effectively guiding the common-mode interference signals to ground to reduce interference with the input signal. The parameters of the capacitive coupling effect include capacitance and coupling distance, and these parameters are optimized to minimize the impact of common-mode interference signals on system performance.

[0057] The current generated flows to ground (GND), including:

[0058] Acquire the common-mode interference signal and identify the voltage change caused by the common-mode interference signal;

[0059] By utilizing the capacitive coupling effect between the first electrode A and the first shielding electrode G1, and between the second electrode B and the second shielding electrode G2, the voltage change caused by the common-mode interference signal is captured.

[0060] Based on the capacitive coupling effect, the captured voltage change is converted into the formed current;

[0061] Obtain the path information of the current flow direction and determine that the path information points to ground (GND);

[0062] Based on path information, the current is guided to GND, thereby reducing or eliminating common-mode interference signals.

[0063] The beneficial effects of the above technical solution are as follows: Common-mode inductors, due to the characteristics of their ferrite cores, suffer from impedance that is significantly affected by the magnitude of the current, thus impacting the filtering effect. Common-mode capacitors solve this problem. The impedance and insertion loss of common-mode capacitors are less affected by the current, maintaining stable filtering characteristics even when no current is flowing. Furthermore, they have higher insertion loss, better filtering effect, and a wider effective filtering frequency band, making them suitable for various noise suppression scenarios. Compared to the winding process of common-mode inductors, the stacking process of common-mode capacitors offers better reliability and product performance consistency. Their smaller size also facilitates product miniaturization.

[0064] In another embodiment, when a differential mode signal is generated between the first electrode A and the second electrode B, the differential mode signal is transmitted through the main path of the circuit, while high-frequency differential mode noise is bypassed through the capacitor between the first electrode A and the second electrode B, without generating current to the ground GND, thereby ensuring the integrity of signal transmission and reducing the impact of differential mode noise.

[0065] The working principle of the above technical solution is as follows: Differential mode signal refers to the signal on two signal lines (such as the first electrode A and the second electrode B) that have equal amplitude but opposite polarities in opposite directions. This signal transmission method is often used to reduce noise because external interference usually affects these two lines in the same way, i.e., common mode noise, while differential mode signals can reduce the impact of this interference by canceling each other out.

[0066] When a differential-mode signal is generated between the first electrode A and the second electrode B, ideally, the signal is transmitted along the main path of the circuit. This main path is designed to ensure that the signal is transmitted efficiently from the transmitter to the receiver, while minimizing possible signal attenuation and interference along the path.

[0067] High-frequency differential-mode noise is a special type of noise that exists at high frequencies between two electrodes. This noise can be bypassed by a capacitor between the two electrodes. The capacitor acts as a filter, allowing the high-frequency noise to pass through instead of allowing it to propagate along the main signal path. The purpose of this is to reduce the impact of high-frequency noise on the main signal path, since the high-frequency noise is bypassed to ground (GND) through the capacitor instead of flowing through the main signal path.

[0068] This principle can be understood through an analogy from everyday life: If you want to pass a ball from one room to another with a wall in between, the most direct way is to open the door (the main path) and pass the ball through the door. However, if there are mosquitoes flying around in the room (high-frequency noise), you might open a small window (capacitor) to let the mosquitoes fly out through the window, rather than letting them interfere with your ball passing. In this way, the ball can be passed smoothly, while the interference from the mosquitoes is minimized.

[0069] By bypassing high-frequency differential-mode noise to ground through a capacitor, the impact of this noise on signal integrity can be effectively reduced, thereby ensuring the quality of signal transmission and reducing errors.

[0070] The beneficial effects of the above technical solution are as follows: This differential mode transmission method helps to suppress common mode signals (signals relative to ground) and improve the system's anti-interference capability; by not causing current flow to ground, it reduces ground loop current, which helps to improve the system's performance and stability; the capacitor allows AC signals to pass through, maintaining signal integrity and facilitating the transmission of accurate differential mode signals.

[0071] In another embodiment, at least one dielectric layer is included between the first electrode A and the second electrode B, through which the dielectric of the dielectric layer provides the required capacitance value and isolates the first electrode A from the second electrode B;

[0072] The first shielding electrode G1 and the second shielding electrode G2 have the same geometry and size to ensure uniform current distribution under common-mode interference.

[0073] The working principle of the above technical solution is as follows: A capacitor is a component used to store electrical energy, based on a non-conductive dielectric layer between two conductive electrodes. When these two electrodes are connected to the positive and negative terminals of a power source, equal amounts of charge with opposite signs accumulate on the electrodes. The dielectric layer prevents the charge from jumping directly from one electrode to the other, thus storing electrical energy. The material and thickness of the dielectric layer directly affect the capacitance value of the capacitor, that is, the capacitor's ability to store charge.

[0074] The first electrode A and the second electrode B are isolated by at least one dielectric layer. This is a capacitor structure. By selecting a suitable dielectric material, it can be ensured that the capacitor provides the required capacitance value. That is, different capacitance values ​​can be obtained by adjusting the material and thickness of the dielectric layer according to the application requirements.

[0075] The first shielding electrode G1 and the second shielding electrode G2 have the same geometry and dimensions. This is to ensure that when the device is subjected to common-mode interference (such as electromagnetic interference from the environment), the current distribution on both shielding electrodes is identical. Common-mode interference typically refers to interference signals acting on two signal lines with the same phase and amplitude. If the shielding electrodes have the same shape and size, their response to electromagnetic fields will also be identical. This ensures that the current generated by the interference on both electrodes is uniform, thereby effectively reducing or eliminating the impact of interference on the circuit.

[0076] Suppose an electronic device is exposed to a strong electromagnetic interference source near its operating frequency. Without proper shielding and interference suppression measures, this interference could enter the device's circuitry via electromagnetic coupling, interfering with its normal operation. By adding shielding electrodes of the same shape and size to the circuit, uniform interference currents can be generated on these electrodes. Through proper circuit design, these interference currents can be canceled out or effectively guided to ground, thus protecting the circuit from interference. This design approach is particularly important in high-frequency circuits and precision measuring equipment, significantly improving the device's anti-interference performance and measurement accuracy.

[0077] The beneficial effects of the above technical solution are as follows: the dielectric layer provides capacitance, enabling differential-mode signals to be transmitted, while isolating the DC portion to ensure that it will not have an adverse effect on the circuit; the identical geometry and size of the shielding electrodes G1 and G2 ensure that the current distribution generated under common-mode interference is uniform, which helps to suppress common-mode signals and improve the anti-interference performance of the system.

[0078] In another embodiment, a dielectric stack layer is formed between the first electrode A and the second electrode B. The dielectric stack layer is stacked in a corresponding order and thickness to filter out or reduce common-mode interference signals.

[0079] The working principle of the above technical solution is as follows: When the first electrode A and the second electrode B are respectively provided with the first electrode and the second electrode, the dielectric stack layer is located between them, acting as a capacitor. Assuming that there is a small differential-mode signal between the first electrode and the second electrode, the common-mode capacitor dielectric layer provides capacitance, allowing the differential-mode signal to pass through. This stack layer design helps to isolate DC current and only allows AC signals to be transmitted.

[0080] The beneficial effects of the above technical solution are as follows: the common-mode capacitor dielectric layer provides the required capacitance, enabling differential-mode signal transmission while blocking DC current; by blocking the DC portion, this design helps prevent the negative impact of DC on the circuit; maintaining stable signal transmission helps improve the performance and stability of the entire system.

[0081] In another embodiment, the dielectric stack layer includes: a first dielectric layer including a first zirconium oxide layer and a first zirconium silicon oxide layer; a second zirconium oxide layer disposed between the first zirconium oxide layer and the first zirconium silicon oxide layer; and a silicon oxide layer disposed between the first zirconium oxide layer and the second zirconium oxide layer.

[0082] The working principle of the above technical solution is as follows: the first zirconia layer provides a certain capacitance and isolates the DC signal, while the differential signal is transmitted through this layer, and the DC part is blocked; the second zirconia layer is located between the first zirconia layer and the first zirconium silicon oxide layer, further providing a capacitance effect to ensure the transmission of differential signals; the zirconium silicon oxide layer is combined with other layers to isolate DC and transmit AC signals; the silicon oxide layer is disposed between the first zirconia layer and the second zirconia layer, providing additional capacitance to facilitate the transmission of differential signals.

[0083] The beneficial effects of the above technical solution are as follows: the multi-layer structure design achieves the capacitance effect at different levels through multi-layer stacking, ensuring the integrity of signal transmission; the structure between layers effectively isolates the DC part, preventing adverse effects on the circuit; the specific materials and structure of each layer help to provide the required capacitance value, ensuring that the differential mode signal is transmitted as expected.

[0084] In another embodiment, a common-mode capacitor is used in an EMC filter, the EMC filter including: a common-mode capacitor, a differential-mode capacitor, and a filter control module;

[0085] The input terminal of the common-mode capacitor is electrically connected to the input terminal of the power supply line, and the output terminal is electrically connected to the input terminal of the load device; the input terminal of the differential-mode capacitor is electrically connected to the output terminal of the common-mode capacitor, and the output terminal is electrically connected to the input terminal of the load device; the control signal input terminal of the filter control module is connected to the control signal output terminals of the common-mode capacitor and the differential-mode capacitor; the filter characteristic adjustment signal output terminal of the filter control module is connected to the adjustment terminal of the common-mode capacitor; the filter control module obtains the filter effect feedback signal through the filter characteristic detection circuit.

[0086] The working principle of the above technical solution is as follows: the input terminal of the common-mode capacitor is connected to the power line, which enables the common-mode capacitor to respond to the signal on the power line and provide the corresponding capacitance effect to prevent common-mode interference from entering the load device; the differential-mode signal is transmitted through the differential-mode capacitor, and the capacitance effect provided by the common-mode capacitor is used to ensure the transmission quality of the differential-mode signal; the control signal input terminal is connected to the control signal output terminals of the common-mode capacitor and the differential-mode capacitor, and the filter control module obtains the status information of the common-mode capacitor and the differential-mode capacitor through these connections for adjustment; the filter characteristic adjustment signal output terminal is connected to the adjustment terminal of the common-mode capacitor, and the filter control module adjusts the filter characteristics of the common-mode capacitor through this connection to adapt to different working conditions.

[0087] The EMC filter includes an adjustable common-mode capacitor, a differential-mode capacitor, and a filter control module.

[0088] The common-mode capacitor's input terminal is electrically connected to the power supply input terminal, and its output terminal is electrically connected to the load device's input terminal. It provides a high-frequency common-mode noise filtering function, suppressing noise within a specific frequency range by dynamically adjusting its capacitance value. The differential-mode capacitor's input terminal is electrically connected to the common-mode capacitor's output terminal, and its output terminal is electrically connected to the load device's input terminal, enhancing the differential noise filtering capability.

[0089] The filter control module includes a microprocessor and a digital-to-analog converter. The microprocessor calculates the filter characteristic adjustment signal based on the feedback signal obtained from the filter characteristic detection circuit. Then, the digital-to-analog converter converts this digital signal into an analog signal, which is used to dynamically adjust the capacitance value of the common-mode capacitor.

[0090] The microprocessor receives feedback signals on the performance and operating status of the filter circuit and analyzes these signals based on a preset signal analysis template. Based on the analysis results, the microprocessor evaluates whether the filter circuit needs to be adjusted to maintain the filtering effect in accordance with the predetermined standard. If adjustment is required, the microprocessor calculates the filter characteristic adjustment signal to optimize the performance of the filter circuit. The digital-to-analog converter converts the filter characteristic adjustment signal from digital form to analog form and outputs it to adjust the capacitance value of the common-mode capacitor.

[0091] The output signal of the filter circuit is monitored and analyzed in real time by the filter characteristic detection circuit to determine the current filtering effect. The obtained feedback signal contains key information such as filter frequency, amplitude change, and phase difference. Based on this information, the filter control module is dynamically adjusted to optimize the filtering effect.

[0092] The beneficial effects of the above technical solution are as follows: the combination of common-mode capacitors and differential-mode capacitors helps to suppress common-mode signals and improve the anti-interference performance of the system; by connecting to the load device, the common-mode capacitor ensures that common-mode interference does not affect the normal operation of the load device; the connection of the differential-mode capacitor enables the differential-mode signal to be transmitted to the load device, ensuring signal integrity; the filter control module adjusts the filtering characteristics of the common-mode capacitor in real time, enabling the system to cope with interference of different frequencies; the filtering effect feedback signal obtained by the filter characteristic detection circuit helps the system adjust in real time to minimize interference.

[0093] In another embodiment, the common-mode capacitor is used to provide filtering for high-frequency common-mode noise, and the suppression of noise signals within a specific frequency range is achieved by selecting the corresponding capacitance value.

[0094] The working principle of the above technical solution is as follows: the common-mode capacitor is designed with common-mode noise within a specific frequency range in mind. By selecting an appropriate capacitance value, noise signals within the target frequency range can be suppressed. The common-mode capacitor provides filtering functionality in the high-frequency range, preventing common-mode noise from entering the system. This helps maintain signal purity and system stability.

[0095] The beneficial effects of the above technical solution are as follows: the selection of common-mode capacitors can effectively suppress high-frequency common-mode noise and improve the anti-interference capability of the system; by preventing the entry of common-mode noise, common-mode capacitors help maintain the purity of the signal and ensure that the load device obtains a high-quality signal.

[0096] In another embodiment, the filter control module includes a microprocessor and a digital-to-analog converter;

[0097] The microprocessor is used to calculate the filter characteristic adjustment signal based on the filter effect feedback signal, and convert the filter characteristic adjustment signal into an analog signal through a digital-to-analog converter to adjust the capacitance value of the common-mode capacitor, thereby realizing the dynamic adjustment of the filter to adapt to different noise environments and ensure that the filter has high-frequency filtering characteristics.

[0098] The calculation of the filter characteristic adjustment signal based on the filter effect feedback signal includes:

[0099] The microprocessor receives a filtering effect feedback signal from the filtering circuit, which indicates the current performance and operating status of the filtering circuit.

[0100] Based on a preset signal analysis template, the microprocessor analyzes the received filtering effect feedback signal to determine the current performance indicators of the filtering circuit. The current performance indicators include the signal amplitude, frequency, phase and noise level.

[0101] Based on the analysis results, the microprocessor evaluates the performance of the filter circuit and determines whether adjustments are needed to ensure that the filtering effect meets the predetermined performance standards.

[0102] If adjustments are needed, the microprocessor calculates a filter characteristic adjustment signal based on the analysis results of the filter effect feedback signal and the preset adjustment algorithm. This filter characteristic adjustment signal aims to optimize the performance of the filter circuit to improve the filter effect.

[0103] The microprocessor converts the calculated filter characteristic adjustment signal from digital form to analog signal through a built-in or external digital-to-analog converter;

[0104] The converted analog filter characteristic adjustment signal output is used to adjust the capacitance value of the common-mode capacitor;

[0105] The common-mode capacitor that receives the analog filter characteristic adjustment signal adjusts its corresponding capacitance value according to the signal to change the characteristics of the filter circuit, thereby optimizing and controlling the filtering effect.

[0106] The working principle of the above technical solution is as follows: the microprocessor analyzes the characteristics of the feedback signal of the filtering effect and calculates the filtering characteristic parameters that need to be adjusted; the calculated filtering characteristic adjustment signal is converted into an analog signal by a digital-to-analog converter; the converted analog signal is used to dynamically adjust the capacitance value of the common-mode capacitor to realize the real-time adjustment of the filter.

[0107] The filtering circuit generates a filtering effect feedback signal, representing the current performance and operating status. This signal contains information such as amplitude, frequency, phase, and noise level. The microprocessor analyzes the filtering effect feedback signal using a preset signal analysis template. Through this analysis, the microprocessor can understand the current performance indicators of the filtering circuit, such as the characteristic parameters of the signal. Based on the analysis results, the microprocessor evaluates the performance of the filtering circuit and determines whether it meets the predetermined performance standards. If the performance does not meet the standards, the microprocessor decides whether to adjust the filtering circuit based on the analysis results and the preset adjustment algorithm. If adjustment is needed, the microprocessor calculates a filtering characteristic adjustment signal based on the analysis results of the filtering effect feedback signal and the adjustment algorithm. This signal aims to optimize the performance of the filtering circuit to improve the filtering effect. The microprocessor converts the calculated filtering characteristic adjustment signal from digital form to an analog signal through a built-in or external digital-to-analog converter. The converted analog filtering characteristic adjustment signal is output to adjust the capacitance value of the common-mode capacitor. The common-mode capacitor adjusts its capacitance value according to the signal, thereby changing the characteristics of the filtering circuit. The adjusted circuit feeds back the new filtering effect, forming a closed-loop system. This process continuously cycles to ensure that the filtering circuit is always in an optimal state, thereby achieving optimization and control of the filtering effect.

[0108] The beneficial effects of the above technical solution are as follows: the microprocessor's calculation and control enable the system to adjust the filter characteristics in real time to adapt to different noise environments; this dynamic adjustment ensures that the filter maintains effective filtering characteristics in the high-frequency range, improving the system's anti-interference capability. The system monitors and optimizes the filter circuit in real time to ensure that it provides optimal performance under different operating conditions.

[0109] Through signal analysis and dynamic adjustment, the system can adapt to different input signals and working environments, improving the adaptability of the filtering circuit. Real-time adjustment by the microprocessor helps maintain the stability of the filtering circuit and avoid performance fluctuations and noise interference. Through digital and automated adjustment, the system reduces the need for human intervention and improves the automation level of the system. By dynamically adjusting the filtering circuit, this system can optimize and control the filtering effect based on real-time performance monitoring and adjustment, thus improving the stability and adaptability of the entire system.

[0110] In another embodiment, the filter control module obtains a filter effect feedback signal through a filter characteristic detection circuit, including:

[0111] The output signal of the filter circuit is monitored and analyzed in real time by the filter characteristic detection circuit to determine the current filtering effect;

[0112] Feedback signals about the filtering effect are obtained from the filter characteristic detection circuit. These feedback signals include key information about the performance of the filter circuit, such as parameters like filter frequency, amplitude change, and phase difference.

[0113] Based on the feedback signal, the filter control module is dynamically adjusted to optimize the filtering effect. This dynamic adjustment includes changing the filter's cutoff frequency, gain, or phase characteristics.

[0114] When the filtering effect detected by the filtering characteristic detection circuit reaches the preset standard or optimization target, the current setting is automatically maintained through the feedback mechanism to ensure the stability and reliability of the filtering effect.

[0115] The working principle of the above technical solution is as follows: The filter characteristic detection circuit monitors and analyzes the output signal of the filter circuit in real time to determine the current filtering effect. For example, when a change in frequency components or an abnormal amplitude is detected, the system will react accordingly. Feedback signals regarding the filtering effect are obtained from the filter characteristic detection circuit, including parameters such as filter frequency, amplitude change, and phase difference. If the frequency deviation exceeds the expected range, the feedback signal will indicate that the cutoff frequency of the filter needs to be adjusted. Based on the feedback signal, the filter control module makes dynamic adjustments to optimize the filtering effect. For example, based on the frequency parameters, the cutoff frequency of the filter can be dynamically changed to adapt to noise of different frequencies. Dynamic adjustment includes changing the cutoff frequency, gain, or phase characteristics of the filter to ensure that the system can maintain a good filtering effect under different noise environments, which helps to adapt to constantly changing noise conditions. When the filtering effect detected by the filter characteristic detection circuit reaches the preset standard or optimization target, the current setting is automatically maintained through the feedback mechanism to ensure the stability and reliability of the filtering effect. This design enables the system to self-adjust and maintain optimal performance under different operating conditions.

[0116] The beneficial effects of the above technical solution are as follows: the filter characteristic detection circuit monitors the output signal of the filter circuit in real time and obtains feedback signals including frequency, amplitude and phase parameters; dynamically adjusts the cutoff frequency, gain or phase of the filter to ensure good filtering effect under different noise environments; automatically maintains settings to ensure stability and reliability. This design helps to adapt to changing noise conditions.

[0117] In another embodiment, the output signal of the filter circuit is monitored and analyzed in real time by a filter characteristic detection circuit, including:

[0118] The filter characteristic detection circuit determines the frequency characteristics of the filter circuit in real time by measuring the frequency response of the output signal;

[0119] The filter characteristic detection circuit includes the filter circuit input and output interfaces to obtain the input and output signals of the filter circuit;

[0120] It also includes a data analysis module, which is used to analyze the characteristics of the output signal of the filter circuit and provide real-time monitoring results;

[0121] By detecting the filtering characteristics of the output signal of the filtering circuit, abnormalities or changes generated by the circuit can be identified, enabling real-time monitoring and analysis of the filtering circuit performance.

[0122] Among them, the abnormalities or changes generated by the identification circuit include:

[0123] Obtain characteristic information of the output signal of the first filter circuit, including frequency response, gain, and phase delay information;

[0124] The characteristic information is used as the performance parameter information of the filter circuit;

[0125] Obtain information about the testing equipment used when performing characteristic testing on the first filter circuit, including information such as signal generator, spectrum analyzer, and oscilloscope;

[0126] Use the testing equipment information as the testing equipment configuration information;

[0127] Obtain operational information on the detection of the output signal of the first filter circuit using detection equipment, including operational information on signal injection, signal acquisition, and signal analysis;

[0128] Use the operation information as the detection operation information;

[0129] Obtain the time information for the detection operation, including the detection start time, detection end time, and detection duration, and use it as a set of detection times;

[0130] The performance parameter information, testing equipment configuration information, testing operation information, and testing time set are used as the first filter circuit performance testing process information;

[0131] Anomaly analysis is performed based on the filter circuit performance testing process information, including:

[0132] Based on performance parameter information, parameters that deviate from the predetermined performance parameters are identified and treated as a set of abnormal parameters.

[0133] Based on the set of abnormal parameters, obtain the corresponding detection operation information and / or the corresponding time within the set of detection times, which are used as the set of abnormal detection times.

[0134] Construct and train a filter circuit anomaly analysis model;

[0135] Input the set of abnormal parameters, abnormal detection operation information and / or abnormal detection time set into the filter circuit abnormal analysis model to obtain the output results;

[0136] Based on the output results, the performance information of the filter circuit to be optimized is obtained.

[0137] The working principle of the above technical solution is as follows: by changing the frequency of the input signal, the amplitude and phase response of the output signal of the filter circuit are measured, thereby obtaining the characteristics of the filter circuit at different frequencies; the filter characteristic detection circuit obtains the input and output signals of the filter circuit through the input and output interfaces to ensure comprehensive monitoring; the data analysis module analyzes the characteristics of the output signal of the filter circuit, such as amplitude and phase, and monitors and identifies anomalies or changes in real time through algorithms.

[0138] As the input signal frequency gradually increases, the response of the filter circuit at different frequencies is detected by measuring the amplitude and phase changes of the output signal; the data analysis module can identify abnormal waveforms, such as abnormal amplitude or phase distortion, indicating performance problems of the filter circuit.

[0139] The beneficial effects of the above technical solution are: it enables real-time monitoring of the performance of the filter circuit and timely detection of anomalies; the data analysis module provides detailed frequency characteristic information, which helps to gain a deeper understanding of the working status of the filter circuit; and by identifying anomalies, maintenance measures can be taken in advance to improve the reliability and stability of the filter circuit.

[0140] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. An application of a common-mode capacitor in an EMC filter, characterized in that, The EMC filter includes: the common-mode capacitor, the differential-mode capacitor, and the filter control module; The input terminal of the common-mode capacitor is electrically connected to the input terminal of the power supply line, and its output terminal is electrically connected to the input terminal of the load device; the input terminal of the differential-mode capacitor is electrically connected to the output terminal of the common-mode capacitor, and its output terminal is electrically connected to the input terminal of the load device; the control signal input terminal of the filter control module is connected to the control signal output terminals of the common-mode and differential-mode capacitors; the filter characteristic adjustment signal output terminal of the filter control module is connected to the adjustment terminal of the common-mode capacitor; the filter control module obtains the filtering effect feedback signal through the filter characteristic detection circuit; The calculation of the filter characteristic adjustment signal based on the filter effect feedback signal includes: The microprocessor receives a filtering effect feedback signal from the filtering circuit corresponding to the EMC filter. This filtering effect feedback signal indicates the current performance and operating status of the filtering circuit. Based on a preset signal analysis template, the microprocessor analyzes the received filtering effect feedback signal to determine the current performance indicators of the filtering circuit. The current performance indicators include the signal amplitude, frequency, phase and noise level. Based on the analysis results, the microprocessor evaluates the performance of the filter circuit and determines whether adjustments are needed to ensure that the filtering effect meets the predetermined performance standards. If adjustments are needed, the microprocessor calculates a filter characteristic adjustment signal based on the analysis results of the filter effect feedback signal and the preset adjustment algorithm. This filter characteristic adjustment signal aims to optimize the performance of the filter circuit to improve the filter effect. The microprocessor converts the calculated filter characteristic adjustment signal from digital form to analog signal through a built-in or external digital-to-analog converter; The converted analog filter characteristic adjustment signal output is used to adjust the capacitance value of the common-mode capacitor; The common-mode capacitor that receives the analog filter characteristic adjustment signal adjusts its corresponding capacitance value according to the signal to change the characteristics of the filter circuit, thereby optimizing and controlling the filtering effect. The filter control module obtains the filter effect feedback signal through the filter characteristic detection circuit, including: The output signal of the filter circuit is monitored and analyzed in real time by the filter characteristic detection circuit to determine the current filtering effect; When the filtering effect detected by the filtering characteristic detection circuit reaches the preset standard or optimization target, the current setting is automatically maintained through the feedback mechanism to ensure the stability and reliability of the filtering effect. Simultaneously, the output signal of the filter circuit is monitored and analyzed in real time through the filter characteristic detection circuit, including: The filter characteristic detection circuit determines the frequency characteristics of the filter circuit in real time by measuring the frequency response of the output signal; The filter characteristic detection circuit includes the filter circuit input and output interfaces to obtain the input and output signals of the filter circuit; It also includes a data analysis module, which is used to analyze the characteristics of the output signal of the filter circuit and provide real-time monitoring results; By detecting the filtering characteristics of the output signal of the filtering circuit, abnormalities or changes generated by the circuit can be identified, thereby enabling real-time monitoring and analysis of the performance of the filtering circuit. Among them, the abnormalities or changes generated by the identification circuit include: Obtain characteristic information of the output signal of the filter circuit, including frequency response, gain, and phase delay information; The characteristic information is used as the performance parameter information of the filter circuit; Obtain information about the testing equipment used when performing characteristic testing on the filter circuit, including signal generator, spectrum analyzer, and oscilloscope; Use the testing equipment information as the testing equipment configuration information; Obtain operational information on the detection of the output signal of the filter circuit using detection equipment, including operational information on signal injection, signal acquisition, and signal analysis; Use the operation information as the detection operation information; Obtain the time information for the detection operation, including the detection start time, detection end time, and detection duration, as a set of detection times; The performance parameter information, testing equipment configuration information, testing operation information, and testing time set are used as the filter circuit performance testing process information; Anomaly analysis is performed based on the filter circuit performance testing process information, including: Based on performance parameter information, parameters that deviate from the predetermined performance parameters are identified and treated as a set of abnormal parameters. Based on the set of abnormal parameters, obtain the corresponding detection operation information and / or the corresponding time within the set of detection times, which are used as the set of abnormal detection times. Construct and train a filter circuit anomaly analysis model; Input the set of abnormal parameters, abnormal detection operation information and / or abnormal detection time set into the filter circuit abnormal analysis model to obtain the output results; Based on the output results, obtain the performance information of the filter circuit to be optimized; Meanwhile, the common-mode capacitor includes: a first electrode A, a second electrode B, a first shielding electrode G1, and a second shielding electrode G2; The positive terminal of the input signal is connected to the first electrode A, the negative terminal of the input signal is connected to the second electrode B, the first shielding electrode G1 is connected to the second shielding electrode G2, and the connection point of the first shielding electrode G1 and the second shielding electrode G2 is connected to ground GND. A capacitor is connected in series between the first electrode A and the first shielding electrode G1, and between the second electrode B and the second shielding electrode G2, to form a common-mode filtering path. At least one dielectric layer is included between the first electrode A and the second electrode B, through which the dielectric of the dielectric layer provides the required capacitance value and isolates the first electrode A from the second electrode B; The first electrode A and the second electrode B are composed of a dielectric stack layer, which is stacked in a corresponding order and thickness to filter out or reduce common-mode interference signals. The dielectric stack layer includes: a first dielectric layer, which includes a first zirconium oxide layer and a first zirconium silicon oxide layer; a second zirconium oxide layer disposed between the first zirconium oxide layer and the first zirconium silicon oxide layer; and a silicon oxide layer disposed between the first zirconium oxide layer and the second zirconium oxide layer.

2. The application of a common-mode capacitor in an EMC filter according to claim 1, characterized in that, Common-mode capacitors are used to provide filtering for high-frequency common-mode noise. By selecting the appropriate capacitance value, noise signals within a specific frequency range can be suppressed.

3. The application of a common-mode capacitor in an EMC filter according to claim 2, characterized in that, The filter control module includes a microprocessor and a digital-to-analog converter; The microprocessor is used to calculate the filter characteristic adjustment signal based on the filter effect feedback signal, and converts the filter characteristic adjustment signal into an analog signal through a digital-to-analog converter to adjust the capacitance value of the common-mode capacitor, thereby realizing the dynamic adjustment of the filter to adapt to different noise environments and ensure that the filter has high-frequency filtering characteristics.

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