Active common-mode attack suppression method and device based on three-phase common-mode inductor

Abstract

The present invention discloses an active common-mode attack suppression device based on a three-phase common-mode inductor, which relates to the field of electromagnetic compatibility. It includes a first-stage common-mode filter module based on a three-phase common-mode ring, which is used to filter out common-mode interference signals in the transmission signal and adaptively adjust the common-mode inductor filtering performance; a second-stage common-mode filter module based on the three-phase common-mode ring, which is used for secondary filtering and tracking residual common-mode interference signals, inputting the residual common-mode interference signals as feedback signals into a feedback control module, and outputting the secondary filtered signals; and a feedback control module, which is used to amplify the feedback signals and regulate the filtering performance of the first-stage common-mode filter module. By adopting an inductor cascade structure, a closed-loop feedback method, and an active excitation control strategy, the present invention can achieve dynamic regulation of filtering capacity without increasing the windings and volume of the filter inductor, adapting to filtering of multiple orders of magnitude common-mode interference signals, and having strong filtering capacity and high universality.

Description

Technical Field

[0001] The present invention relates to the field of electromagnetic compatibility, and in particular to a method and device for suppressing active common-mode attacks based on three-phase common-mode inductors. Background Art

[0002] With the continuous advancement of electronic technology, the electromagnetic environment in which electronic devices operate has become increasingly complex, and the risk of electromagnetic interference has correspondingly increased dramatically. Electromagnetic interference is primarily categorized into differential-mode interference and common-mode interference. Differential-mode interference refers to voltage signals with equal amplitude and opposite phase between a signal line and its return line (generally referred to as the signal ground). Interference current loops flow in the loop formed by the conductor and a reference object. Therefore, differential-mode interference can directly alter the operating voltage of electronic devices, thereby affecting their proper operation. Common-mode interference refers to interference voltages with equal amplitude and phase on a signal line and its return line (generally referred to as the signal ground). In theory, common-mode interference does not generate differential-mode voltage across electronic devices. However, common-mode interference can cause cables to emit strong electromagnetic radiation, interfering with other circuit components or surrounding electronic devices. Common-mode interference can also form interference current loops through parasitic capacitance, affecting device operation. Furthermore, if there is electrical imbalance, the amplitude and phase of the common-mode interference currents on different conductors in the system will differ. In this case, common-mode interference can transform into differential-mode interference, seriously affecting signal quality. A major source of common-mode interference in IoT devices is the power supply module. Therefore, in order to ensure the safe and reliable operation of IoT devices, it is very important to adopt effective and reliable electromagnetic interference filtering and vulnerability detection for the power supply modules of the devices.

[0003] Currently, methods for suppressing differential-mode interference on power transmission lines are relatively mature, such as low-pass filters. Differential amplifier circuits or passive common-mode inductors are commonly used to suppress common-mode interference on power lines. However, these circuits can only suppress common-mode interference within a specific bandwidth. For example, when the common-mode interference intensity is high, a single passive common-mode inductor cannot completely filter out the interference due to the common-mode impedance limitation. To achieve better filtering effects, that is, to increase the common-mode impedance, the only options are to increase the core volume of the common-mode inductor, enhance the excitation voltage, or increase the number of winding turns. However, in practical applications, increasing the number of windings is not feasible. As electrical complexity increases, the forms and magnitudes of common-mode interference are becoming increasingly complex and varied, placing higher performance and adaptability demands on common-mode interference filtering circuits.

[0004] To ensure the reliable operation of IoT devices, how to actively adjust the filtering performance according to the size of common-mode interference and improve the interference suppression effect without increasing the number of winding turns and the volume of the core is an urgent problem to be solved. Summary of the Invention

[0005] In response to the problems of current passive common-mode filters such as limited bandwidth, incomplete interference filtering, and easy resonance with the line due to fixed parameters, the present invention proposes an active common-mode attack suppression method and device based on three-phase common-mode inductors. Through closed-loop feedback and active excitation, it automatically tracks the interference signal and actively adjusts the filtering performance, achieving better interference suppression effect.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides an active common-mode attack suppression device based on a three-phase common-mode inductor, comprising:

[0008] The first-stage common-mode filter module based on the three-phase common-mode ring is used to filter out common-mode interference signals in the transmission signal and adaptively adjust the common-mode inductor filtering performance;

[0009] The second-stage common-mode filtering module based on the three-phase common-mode ring is used for secondary filtering and tracking of residual common-mode interference signals. The residual common-mode interference signals are input into the feedback control module as feedback signals, and the secondary filtered signals are output;

[0010] The feedback control module is used to amplify the feedback signal and regulate the filtering performance of the first-stage common-mode filtering module.

[0011] Furthermore, the first-stage common-mode filter module and the second-stage common-mode filter module are respectively composed of a three-phase common-mode ring, and the output ends of the first phase winding and the second phase winding of the first-stage common-mode filter module are respectively connected to the input ends of the first phase winding and the second phase winding of the second-stage common-mode filter module, and the input ends of the first phase winding and the second phase winding of the first-stage common-mode filter module and the output ends of the first phase winding and the second phase winding of the second-stage common-mode filter module are connected to the external electrical circuit, and the transmission signal of the external electrical circuit is filtered by the first-stage common-mode filter module and the second-stage common-mode filter module in sequence and then output; the third phase winding of the second-stage common-mode filter module is connected to the third phase winding of the first-stage common-mode filter module through the feedback control module.

[0012] Furthermore, the input ends of the first phase winding and the second phase winding of the first-stage common-mode filtering module are respectively connected to the signal line and the ground line of the external electrical circuit.

[0013] Furthermore, the feedback control module adopts a dual-input dual-output amplifier.

[0014] Furthermore, the two ends of the third phase winding of the second-stage common-mode filter module are connected to the two input ends of the amplifier, and the two ends of the third phase winding of the first-stage common-mode filter module are connected to the output end of the amplifier, and the direction of the magnetic flux generated by the induced signal is the same as the direction of the magnetic flux generated by the first and second phase windings.

[0015] Furthermore, the common-mode inductance of the three-phase common-mode ring in the first-stage common-mode filtering module is greater than the common-mode inductance of the three-phase common-mode ring in the second-stage common-mode filtering module.

[0016] The active common-mode attack suppression method of the active common-mode attack suppression device based on the three-phase common-mode inductor includes:

[0017] The output signal line and ground line of the external electrical circuit are connected to the input terminals of the first phase winding and the second phase winding of the first-stage common-mode filter module respectively. When the transmission signal passes through the first phase winding and the second phase winding of the first-stage common-mode filter module, the common-mode interference signal in the transmission signal is suppressed, and the differential-mode voltage signal passes smoothly.

[0018] When the transmission signal passes through the first-phase winding and the second-phase winding of the second-stage common-mode filter module, the residual common-mode interference signal is suppressed, and the differential-mode voltage signal passes smoothly. At the same time, the presence of the residual common-mode interference signal causes the third-phase winding of the second-stage common-mode filter module to generate an induced current, which is amplified by the feedback control module and then transmitted to the third-phase winding of the first-stage common-mode filter module.

[0019] Since the winding phases of the third-phase winding are the same as those of the first and second-phase windings, the current of the third-phase winding transmitted to the first-stage common-mode filter module reversely compensates the magnetic flux in the magnetic ring, automatically adjusting the first-stage common-mode filter module's ability to suppress common-mode interference signals until the first-stage common-mode filter module can completely filter out the common-mode interference signals.

[0020] The signals output from the first phase winding and the second phase winding of the second-stage common-mode filter module are respectively connected to the input signal line and the ground line of the external electrical circuit.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The active common-mode attack suppression device designed by the present invention to address the common-mode interference problem of transmission lines is simple, low-cost, small in size, and easy to operate, and can be directly connected to the transmission line that needs to be filtered.

[0023] (2) The present invention adopts a cascade structure of two three-phase common-mode inductors and a feedback control method, which can detect residual interference signals and timely adjust the filtering performance of the first-stage filtering module according to actual conditions, improve the filtering accuracy, and obtain better filtering effects. It is suitable for situations where the circuit is complex and changeable. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a module block diagram of the active common-mode attack suppression device based on three-phase common-mode inductance proposed by the present invention;

[0025] Figure 2Schematic diagram of the circuit connection of the active common-mode attack suppression device based on three-phase common-mode inductance proposed by the present invention;

[0026] Figure 3 This is a comparison diagram of the output signals of the active filter proposed in the present invention and the traditional passive filter under the same common-mode interference. DETAILED DESCRIPTION

[0027] The present invention is further described below with reference to the accompanying drawings and embodiments. The accompanying drawings are merely schematic illustrations of the present invention. Some of the block diagrams shown in the accompanying drawings are functional entities that do not necessarily correspond to physically or logically independent entities. These functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different networks and / or processor systems and / or microcontroller systems.

[0028] This invention proposes an active common-mode attack suppression device based on three-phase common-mode inductors, which is used to filter out common-mode interference signals in electronic transmission lines and ensure reliable signal transmission. The specific implementation process is as follows:

[0029] like Figure 1 As shown, the device consists of three parts: the first-stage common-mode filter module, the second-stage common-mode filter and the feedback control module. Specifically, it includes: a three-phase common-mode ring with a large common-mode inductance, a three-phase common-mode ring with a small common-mode inductance, and a differential amplifier. The connections between the modules are as follows: Figure 2 shown.

[0030] Among them, the first-stage common-mode filter module uses a three-phase common-mode ring with a large common-mode inductance to filter out the common-mode interference signal on the transmission line and receive feedback signals, actively adjusting the inductance value of the filter module.

[0031] The second-stage common-mode filtering module uses a three-phase common-mode ring with a small common-mode inductance for secondary filtering and sensing of residual common-mode interference signals, and transmits the sensing signals to the feedback control module.

[0032] The feedback control module is used to receive and amplify the residual interference sensed by the second-stage common-mode filter module and feed it back to the third-phase winding of the first-stage common-mode filter module, so as to actively adjust the inductance value of the first-stage filter module, that is, dynamically adjust the filtering capability.

[0033] The present invention utilizes a cascaded inductor structure, a closed-loop feedback method, and an active excitation control strategy to dynamically adjust the system's filtering capacity. This allows for dynamic adjustment of filtering capacity without increasing the number of filter inductor windings or the size of the filter, adapting to filtering multiple levels of common-mode interference signals. This provides strong filtering capabilities and high universality. Taking a mobile device charging transmission line as an example, the specific workflow of the proposed device includes the following steps:

[0034] Step 1: Connect the device to the transmission line. Figure 2 As shown, the input ends of the first-phase and second-phase windings in the first-stage common-mode filter module are respectively connected to the signal line and the ground line of the charging line, and the output ends of the first-phase and second-phase windings in the first-stage common-mode filter module are respectively connected to the input ends of the first-phase and second-phase windings in the second-stage common-mode filter module, and the output ends of the first-phase and second-phase windings in the second-stage common-mode filter module serve as the output ends of the active common-mode attack suppression device of the present invention; the winding directions of the three-phase coils of the three-phase common-mode ring are the same. In this example, the input and output ends of the device are connected to a USB female connector and a USB male connector, which is convenient for connecting the charging line and the mobile device, that is, the charging port of the mobile phone. When the first-phase and second-phase windings in the first-stage common-mode filter module are connected to the first-phase and second-phase windings in the second-stage common-mode filter module, the connection order is not limited, Figure 2 Taking into account the neatness of the connection, the first phase winding in the first-stage common-mode filter module is connected to the second phase winding in the second-stage common-mode filter module, and the second phase winding in the first-stage common-mode filter module is connected to the first phase winding in the second-stage common-mode filter module. According to the connection relationship, the positive and negative ends of the output signal are defined.

[0035] In step 2, when the signal passes through the first-phase and second-phase windings of the first-stage common-mode filter module, the magnetic flux generated by the common-mode interference signal in the magnetic ring will be superimposed, increasing the common-mode inductance and thus suppressing the common-mode noise in the transmission line. Conversely, when the differential-mode voltage signal flows through the first-phase and second-phase windings, the generated magnetic flux cancels each other, allowing the differential-mode voltage signal to pass smoothly.

[0036] Step 3: When the signal passes through the second-stage common-mode filter module, the common-mode interference signal that is not completely filtered out further flows into the second-stage common-mode filter module. At the same time, due to the change of magnetic flux in the magnetic ring, an induced current will be generated on the third-phase winding of the second-stage common-mode filter and transmitted to the feedback differential amplifier.

[0037] In step 4, the induced current generated by the third-phase winding of the second-stage common-mode filter is first amplified by a differential amplifier, and then transmitted to the third-phase winding of the first-stage common-mode filter module. Since the third-phase winding has the same winding direction as the first-phase and second-phase windings, the amplified differential-mode signal will further reversely compensate for the magnetic flux in the magnetic ring, thereby adjusting the first-stage common-mode filter module's ability to suppress the common-mode interference signal until the first-stage common-mode filter module can completely filter out the common-mode interference signal. In this embodiment, a sinusoidal common-mode interference signal with an amplitude of 300Vpp and a frequency of 500kHz is injected into the mobile phone charging cable end. Figure 3The figures are the original common-mode interference signal, the output signal filtered by the passive common-mode inductor, and the output signal filtered by the active filter of the present invention. The output signals show that the passive common-mode inductor cannot completely filter out the signal, while the detection and prevention method for power supply vulnerability of IoT devices proposed in this invention can almost completely filter out the interference signal, achieving better filtering effect.

[0038] The active common-mode interference filtering device based on three-phase inductor feedback control proposed in the present invention has the advantages of adaptive filtering performance, interference tracking, low cost, small size, and wide bandwidth. It utilizes the three-phase common-mode inductor cascade structure, deviation tracking and feedback control, and the method of actively exciting and controlling the inductor to overcome the problems of passive common-mode filters such as limited bandwidth, easy resonance with the circuit, large size of high-filtering performance devices, and incomplete filtering.

[0039] The above examples are merely specific embodiments of the present invention. Obviously, the present invention is not limited to the above examples, and many variations are possible. All variations that can be directly derived or imagined by a person skilled in the art from the disclosure of the present invention should be considered to be within the scope of protection of the present invention.

Claims

1. An active common-mode attack suppression device based on three-phase common-mode inductors, characterized in that: include: The first-stage common-mode filter module based on the three-phase common-mode ring is used to filter out common-mode interference signals in the transmission signal and adaptively adjust the common-mode inductor filtering performance; The second-stage common-mode filtering module based on the three-phase common-mode ring is used for secondary filtering and tracking of residual common-mode interference signals. The residual common-mode interference signals are input into the feedback control module as feedback signals, and the secondary filtered signals are output; A feedback control module, used to amplify the feedback signal and adjust the filtering performance of the first-stage common-mode filtering module; The first-stage common-mode filter module and the second-stage common-mode filter module are each composed of a three-phase common-mode ring, and the common-mode inductance of the three-phase common-mode ring in the first-stage common-mode filter module is greater than the common-mode inductance of the three-phase common-mode ring in the second-stage common-mode filter module; the output ends of the first phase winding and the second phase winding of the first-stage common-mode filter module are respectively connected to the input ends of the first phase winding and the second phase winding of the second-stage common-mode filter module, and the input ends of the first phase winding and the second phase winding of the first-stage common-mode filter module and the output ends of the first phase winding and the second phase winding of the second-stage common-mode filter module are connected to an external electrical circuit, and the transmission signal of the external electrical circuit is filtered by the first-stage common-mode filter module and the second-stage common-mode filter module in sequence and then output; The third phase winding of the second-stage common-mode filter module is connected to the third phase winding of the first-stage common-mode filter module through the feedback control module; The feedback control module adopts a dual-end input and dual-end output amplifier; the two ends of the third phase winding of the second-stage common-mode filter module are connected to the two input ends of the amplifier, and the two ends of the third phase winding of the first-stage common-mode filter module are connected to the output ends of the amplifier, and the direction of the magnetic flux generated by the induced signal is the same as the direction of the magnetic flux generated by the first and second phase windings.

2. The active common-mode attack suppression device based on three-phase common-mode inductance according to claim 1 is characterized in that: Input ends of the first phase winding and the second phase winding of the first-stage common-mode filter module are connected to a signal line and a ground line of an external electrical circuit respectively.

3. The active common-mode attack suppression method of the active common-mode attack suppression device based on three-phase common-mode inductance according to claim 1 is characterized in that: include: The output signal line and ground line of the external electrical circuit are connected to the input terminals of the first phase winding and the second phase winding of the first-stage common-mode filter module respectively. When the transmission signal passes through the first phase winding and the second phase winding of the first-stage common-mode filter module, the common-mode interference signal in the transmission signal is suppressed, and the differential-mode voltage signal passes smoothly. When the transmission signal passes through the first-phase winding and the second-phase winding of the second-stage common-mode filter module, the residual common-mode interference signal is suppressed, and the differential-mode voltage signal passes smoothly. At the same time, the presence of the residual common-mode interference signal causes the third-phase winding of the second-stage common-mode filter module to generate an induced current, which is amplified by the feedback control module and then transmitted to the third-phase winding of the first-stage common-mode filter module. Since the winding phases of the third-phase winding are the same as those of the first and second-phase windings, the current of the third-phase winding transmitted to the first-stage common-mode filter module reversely compensates the magnetic flux in the magnetic ring, automatically adjusting the first-stage common-mode filter module's ability to suppress common-mode interference signals until the first-stage common-mode filter module can completely filter out the common-mode interference signals. The signals output from the first phase winding and the second phase winding of the second-stage common-mode filter module are respectively connected to the input signal line and the ground line of the external electrical circuit.

4. The active common-mode attack suppression method of the active common-mode attack suppression device based on three-phase common-mode inductance according to claim 3 is characterized in that: The common-mode inductance of the three-phase common-mode ring in the first-stage common-mode filtering module is greater than the common-mode inductance of the three-phase common-mode ring in the second-stage common-mode filtering module.

5. The active common-mode attack suppression method of the active common-mode attack suppression device based on three-phase common-mode inductance according to claim 3 is characterized in that: The feedback control module adopts a dual-end input and dual-end output amplifier.

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