A feedforward integrated AEF with injection loop multiplexing

Abstract

This application relates to a front-feedback integrated AEF with injection loop multiplexing, comprising a current sampling circuit for acquiring the common-mode noise current of the main circuit and converting it into a sampled voltage signal; a signal processing circuit, with its input terminal coupled to the output terminal of the current sampling circuit, simultaneously generating a feedforward compensation signal and a feedback compensation signal through a single operational amplifier, for amplifying the sampled voltage signal to generate a compensation signal; a coupling injection branch connected to the feedforward injection node of the main circuit, for injecting the compensation signal into the main circuit in a feedforward manner; and a feedback injection branch connected to the feedback injection node of the main circuit, for injecting the compensation signal into the main circuit in a feedback manner. This application simplifies the circuit, reduces costs, improves integration, effectively suppresses common-mode interference, enhances operational stability, and better meets the electromagnetic compatibility (EMC) requirements of power electronic equipment.

Description

Technical Field

[0001] This application relates to the field of electromagnetic compatibility technology, and in particular to a front feedback integrated AEF with injection loop multiplexing. Background Technology

[0002] With the widespread adoption of wide-bandgap semiconductor devices such as silicon carbide (SiC) and gallium nitride (GaN), power electronic systems are continuously iterating towards higher frequencies, higher power densities, and smaller sizes. The common-mode electromagnetic interference (EMC) problem caused by high-frequency switching is becoming increasingly prominent, severely impacting the electromagnetic compatibility (EMC) performance and operational stability of equipment. Active electromagnetic interference (AEF) filters, with their advantages of small size and flexible, adjustable filtering characteristics, have become the mainstream technology for suppressing common-mode interference. They effectively suppress common-mode noise by sampling, processing, and compensating for interference signals.

[0003] In existing technologies, a discrete architecture with multiple operational amplifiers is typically employed. Independent operational amplifiers are used to construct feedforward and feedback compensation circuits. The sampled common-mode interference signal is amplified through multiple stages and then injected into the main circuit via independent compensation branches to suppress common-mode noise. Some existing technologies employ a single compensation mode design, using only a single branch of feedforward or feedback compensation to suppress common-mode interference, with the compensation signal generation circuit and the main circuit compensation branch being independent of each other. However, these existing technologies have significant technical problems: the discrete architecture with multiple operational amplifiers requires multiple operational amplifiers and a large number of discrete components, resulting in a large number of components, high hardware costs, and low circuit integration. Furthermore, the independent operation of the feedforward and feedback compensation circuits prevents the reuse of signal processing units and compensation branches, leading to redundant circuit structures and poor compactness. Simultaneously, the single compensation mode only achieves single compensation signal injection, resulting in a single dimension of common-mode interference suppression and failing to synergistically improve the common-mode noise suppression effect, making it difficult to meet the requirements of high-frequency power electronic systems for efficient, compact, and low-cost common-mode interference suppression.

[0004] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] To address the aforementioned issues, this application provides a front feedback integrated AEF with injection loop multiplexing, which simplifies the circuit, reduces costs, improves integration, effectively suppresses common-mode interference, enhances operational stability, and better meets the electromagnetic compatibility (EMC) requirements of power electronic equipment.

[0006] To achieve the objectives of this application, the following technical solution is provided: This application provides a front-feedback integrated AEF with injection loop multiplexing, including: The current sampling circuit is used to collect the common-mode noise current of the main circuit and convert it into a sampling voltage signal; The signal processing circuit, with its input terminal coupled to the output terminal of the current sampling circuit, generates both a feedforward compensation signal and a feedback compensation signal simultaneously through a single operational amplifier. These signals are used to amplify the sampled voltage signal and generate the compensation signal. The coupling injection branch is connected to the feedforward injection node of the main circuit and is used to inject the compensation signal into the main circuit in a feedforward manner. The feedback injection branch is connected to the feedback injection node of the main circuit and is used to inject the compensation signal into the main circuit in a feedback manner.

[0007] In one possible implementation, the current sampling circuit includes a primary winding assembly of a current transformer, a secondary winding of a current transformer, and a sampling resistor. The primary winding assembly of the current transformer includes a first primary winding and a second primary winding, which are connected in series in the positive and negative busbars of the main circuit, respectively, and are located between the feedforward injection node and the feedback injection node. The secondary winding of the current transformer is connected in parallel with the sampling resistor and magnetically coupled to the primary winding assembly of the current transformer, converting the coupled common-mode noise current into a voltage signal.

[0008] In one possible implementation, the signal processing circuit includes a feedforward amplification impedance component, a feedback amplification impedance, and an operational amplifier; The feedforward amplification impedance assembly includes a first feedforward amplification impedance and a second feedforward amplification impedance; one end of the first feedforward amplification impedance is connected to the output terminal of the current sampling circuit, and the other end is connected to the inverting input terminal of the operational amplifier; one end of the second feedforward amplification impedance is connected to the inverting input terminal of the operational amplifier, and the other end is connected to the coupling injection branch, with the connection node being the first node; The feedback amplification impedance is connected between the first node and the output of the operational amplifier. The non-inverting input of the operational amplifier is grounded.

[0009] In one possible implementation, the coupled injection branch includes a feedforward DC blocking injection capacitor assembly and a feedforward injection impedance; The feedforward DC blocking injection capacitor assembly includes a first feedforward DC blocking injection capacitor and a second feedforward DC blocking injection capacitor, which are connected in series with the positive and negative busbars near the linear impedance stabilization network (LISN) side, respectively, and the common midpoint of the two is the feedforward injection node. The feedforward injection impedance is connected in series between the first node and the feedforward injection node.

[0010] In one possible implementation, the feedback injection branch includes a feedback injection impedance and a feedback DC blocking injection capacitor assembly; The feedback DC blocking injection capacitor assembly includes a first feedback DC blocking injection capacitor and a second feedback DC blocking injection capacitor, which are connected in series with the positive and negative busbars near the test equipment (EUT) side, respectively, and the common midpoint of the two is the feedback injection node; The feedback injection impedance is connected in series between the output of the operational amplifier and the feedback injection node.

[0011] In one possible implementation, the first feedforward DC blocking injection capacitor has the same capacitance value as the second feedforward DC blocking injection capacitor, and the first feedback DC blocking injection capacitor has the same capacitance value as the second feedback DC blocking injection capacitor.

[0012] In one possible implementation, the capacitance values ​​of the first feedforward DC blocking injection capacitor, the second feedforward DC blocking injection capacitor, the first feedback DC blocking injection capacitor, and the second feedback DC blocking injection capacitor are the same.

[0013] In one possible implementation, the signal processing circuit generates feedforward compensation signals and feedback compensation signals with different amplification factors through the operational amplifier.

[0014] In one possible implementation, based on the first formula, the feedforward amplification impedance component in the signal processing circuit, the sampling resistor in the current sampling circuit, the primary winding component of the current transformer, the secondary winding of the current transformer, and the feedforward DC blocking injection capacitor component and feedforward injection impedance in the coupling injection branch are adjusted so that the equivalent impedance of the feedforward injection part is approximately 0, thereby improving the filtering effect of common-mode electromagnetic interference. The first formula is:

[0015] in, The equivalent impedance of the feedforward injection section. This is the equivalent impedance of a linear impedance-stabilized network. For feedforward injection impedance, The impedance of the feedforward DC blocking injection capacitor. This is the second feedforward amplification impedance. The first feedforward amplification impedance, For sampling resistor, This represents the turns ratio of the current transformer.

[0016] In one possible implementation, based on the second formula, the feedforward DC blocking injection capacitor component and feedforward injection impedance of the coupling injection branch, the sampling resistor, the primary winding component of the current transformer, the secondary winding of the current transformer in the current sampling circuit, the feedforward amplification impedance component, the feedback amplification impedance, and the operational amplifier of the signal processing circuit are adjusted to achieve operational amplifier outputs with different amplification factors, thereby improving the suppression effect on common-mode noise. The second formula is:

[0017] in, This is the compensation signal voltage output by the operational amplifier. This is the second feedforward amplification impedance. The first feedforward amplification impedance, The turns ratio of the current transformer. For sampling resistor, For feedback amplification impedance, The impedance of the feedforward DC blocking injection capacitor. For feedforward injection impedance, The common-mode noise current of the main circuit. This is the common-mode noise voltage of the main circuit.

[0018] The technical solution provided in this application may include the following beneficial effects: The feedforward integrated AEF with injection loop multiplexing provided in this application can simultaneously generate feedforward compensation signals and feedback compensation signals using only a single operational amplifier, simplifying the structure of the signal processing circuit, realizing injection loop multiplexing, reducing redundant devices and hardware costs, and improving circuit integration. Furthermore, by coordinating the coupling injection branch and the feedback injection branch to inject the compensation signal into the main circuit, the common-mode electromagnetic interference of the main circuit is effectively suppressed, improving the common-mode noise suppression effect. At the same time, the circuit structure is compact and has strong operating stability, better meeting the electromagnetic compatibility requirements of power electronic equipment.

[0019] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0020] The accompanying drawings are provided to further understand this application and form part of the specification. They are used together with the embodiments of the invention to explain this application and do not constitute a limitation thereof. Obviously, the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0021] Figure 1A schematic diagram of a front-feedback integrated AEF structure for injection loop reuse provided in an embodiment of this application; Figure 2 An equivalent circuit diagram of a front feedback integrated AEF with injection loop multiplexing is provided for an embodiment of this application; Figure 3 This application provides a use case diagram for a front-feedback integrated AEF with injection loop multiplexing, as shown in the embodiments of this application. Figure 4 A common-mode noise spectrum of a front-feedback integrated AEF non-start active filter with injection loop multiplexing provided in this application embodiment; Figure 5 The common-mode noise spectrum of a front-feedback integrated AEF-start active filter with injection loop multiplexing is provided in an embodiment of this application.

[0022] Figure label: 100, Feedforward DC blocking injection capacitor assembly; 110, First feedforward DC blocking injection capacitor; 120, Second feedforward DC blocking injection capacitor. 200, Feedforward injection impedance; 300, Secondary winding of current transformer; 400, Sampling resistor; 500. Primary winding assembly of current transformer; 510. Primary winding of first current transformer; 520. Primary winding of second current transformer. 600, Feedforward amplification impedance assembly; 610, First feedforward amplification impedance; 620, Second feedforward amplification impedance; 700, Operational amplifier; 800, Feedback amplification impedance; 900, Feedback injection impedance; 1000, Feedback DC blocking injection capacitor assembly; 1010, First feedback DC blocking injection capacitor; 1020, Second feedback DC blocking injection capacitor. Detailed Implementation

[0023] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that this disclosure will be more comprehensive and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0024] Furthermore, the accompanying drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore, repeated descriptions of them will be omitted.

[0025] This example implementation first provides a front-feedback integrated AEF with injection loop multiplexing. (See reference...) Figure 1As shown, this type of injection loop multiplexing front feedback integrated AEF includes a current sampling circuit, a signal processing circuit, a coupling injection branch, and a feedback injection branch.

[0026] The current sampling circuit is used to collect the common-mode noise current of the main circuit and convert it into a sampling voltage signal. The signal processing circuit, with its input terminal coupled to the output terminal of the current sampling circuit, generates both a feedforward compensation signal and a feedback compensation signal simultaneously through a single operational amplifier. These signals are used to amplify the sampled voltage signal and generate the compensation signal. The coupling injection branch is connected to the feedforward injection node of the main circuit and is used to inject the compensation signal into the main circuit in a feedforward manner. The feedback injection branch is connected to the feedback injection node of the main circuit and is used to inject the compensation signal into the main circuit in a feedback manner.

[0027] It should be noted that the pre-feedback integrated AEF with injection loop multiplexing consists of four core parts: current sampling circuit, signal processing circuit, coupling injection branch, and feedback injection branch. These parts are electrically connected to form a closed-loop working circuit. The current sampling circuit collects the common-mode noise signal of the main circuit through magnetic coupling. The signal processing circuit amplifies the signal and generates the compensation signal through a single operational amplifier 700. The coupling injection branch and the feedback injection branch inject the compensation signal into the main circuit in the form of feedforward and feedback, respectively. The four components work together to achieve efficient suppression of common-mode electromagnetic interference.

[0028] In one possible implementation, the current sampling circuit includes a primary winding assembly 500 of a current transformer, a secondary winding 300 of a current transformer, and a sampling resistor 400. The primary winding assembly 500 of the current transformer includes a first primary winding 510 and a second primary winding 520 of the current transformer, which are connected in series in the positive and negative busbars of the main circuit, respectively, and are located between the feedforward injection node and the feedback injection node. The secondary winding 300 of the current transformer is connected in parallel with the sampling resistor 400 and is magnetically coupled to the primary winding assembly 500 of the current transformer, converting the coupled common-mode noise current into a voltage signal.

[0029] It should be noted that in the current sampling circuit, the first primary winding 510 and the second primary winding 520 of the current transformer primary winding assembly 500 are connected in series on the positive and negative busbars of the main circuit, and are only magnetically coupled to the secondary winding 300 of the current transformer, without direct electrical connection; the secondary winding 300 of the current transformer is connected in parallel with the sampling resistor 400, which can accurately convert the common-mode noise current obtained by magnetic coupling into a sampling voltage signal, providing a stable input signal for the subsequent signal processing circuit.

[0030] In one possible implementation, the signal processing circuit includes a feedforward amplification impedance component 600, a feedback amplification impedance 800, and an operational amplifier 700. The feedforward amplification impedance assembly 600 includes a first feedforward amplification impedance 610 and a second feedforward amplification impedance 620; one end of the first feedforward amplification impedance 610 is connected to the output terminal of the current sampling circuit, and the other end is connected to the inverting input terminal of the operational amplifier 700; one end of the second feedforward amplification impedance 620 is connected to the inverting input terminal of the operational amplifier 700, and the other end is connected to the coupling injection branch, with the connection node being the first node; The feedback amplification impedance 800 is connected between the first node and the output terminal of the operational amplifier 700, and together with the feedforward DC blocking injection capacitor component 100, the feedforward injection impedance 200, the first feedforward amplification impedance 610, the second feedforward amplification impedance 620, and the operational amplifier 700, it forms a feedback amplification circuit. The non-inverting input terminal of the operational amplifier 700 is grounded.

[0031] It should be noted that in the signal processing circuit, the first feedforward amplification impedance 610 and the second feedforward amplification impedance 620 of the feedforward amplification impedance component 600 respectively realize the sampling signal transmission and feedforward signal coupling; the feedback amplification impedance 800 is connected between the first node and the output terminal of the operational amplifier 700, and together with the feedforward DC blocking injection capacitor component 100, the feedforward injection impedance 200, the first feedforward amplification impedance 610, the second feedforward amplification impedance 620, and the operational amplifier 700, they form a feedback amplification loop; the grounding of the non-inverting input terminal of the operational amplifier 700 can ensure the stability of the reference potential for signal amplification and avoid common-mode interference from being introduced into the amplification circuit.

[0032] In one possible implementation, the coupled injection branch includes a feedforward DC blocking injection capacitor assembly 100 and a feedforward injection impedance 200; The feedforward DC blocking injection capacitor assembly 100 includes a first feedforward DC blocking injection capacitor 110 and a second feedforward DC blocking injection capacitor 120, which are connected in series with the positive and negative busbars near the LISN side, respectively, and the common midpoint of the two is the feedforward injection node. The feedforward injection impedance 200 is connected in series between the first node and the feedforward injection node.

[0033] It should be noted that in the coupling injection branch, the first feedforward DC blocking injection capacitor 110 and the second feedforward DC blocking injection capacitor 120 of the feedforward DC blocking injection capacitor assembly 100 are symmetrically connected in series in the main circuit on the LISN side. The feedforward injection node formed by their common midpoint is connected in series with the first node of the signal processing circuit through the feedforward injection impedance 200, which can smoothly inject the compensation signal into the main circuit. At the same time, the feedforward DC blocking injection capacitor assembly 100 can block DC signals and only allow AC signals to pass through.

[0034] In one possible implementation, the feedback injection branch includes a feedback injection impedance 900 and a feedback DC blocking injection capacitor assembly 1000; The feedback DC blocking injection capacitor assembly 1000 includes a first feedback DC blocking injection capacitor 1010 and a second feedback DC blocking injection capacitor 1020, which are connected in series with the positive and negative busbars near the EUT side, respectively, and the common midpoint of the two is the feedback injection node. The feedback injection impedance 900 is connected in series between the output of the operational amplifier 700 and the feedback injection node.

[0035] It should be noted that in the feedback injection branch, the first feedback DC blocking injection capacitor 1010 and the second feedback DC blocking injection capacitor 1020 of the feedback DC blocking injection capacitor assembly 1000 are symmetrically connected in series in the main circuit on the EUT side. Their common midpoint forms the feedback injection node. The feedback injection impedance 900 transmits the compensation signal output by the operational amplifier 700 to this node, realizing feedback compensation injection. The feedback DC blocking injection capacitor assembly 1000 also has the dual function of DC blocking and common-mode signal transmission.

[0036] In one possible implementation, the first feedforward DC blocking injection capacitor 110 and the second feedforward DC blocking injection capacitor 120 have the same capacitance value, and the first feedback DC blocking injection capacitor 1010 and the second feedback DC blocking injection capacitor 1020 have the same capacitance value.

[0037] It should be noted that the first feedforward DC blocking injection capacitor 110 and the second feedforward DC blocking injection capacitor 120 have the same capacitance value, and the first feedback DC blocking injection capacitor 1010 and the second feedback DC blocking injection capacitor 1020 have the same capacitance value. The symmetrical capacitor configuration can ensure that the common-mode signal coupling and compensation injection of the positive and negative buses of the main circuit are completely symmetrical, avoid the introduction of differential-mode interference due to differences in device parameters, and ensure the common-mode filtering effect.

[0038] Furthermore, the capacitance values ​​of the first feedforward DC blocking injection capacitor 110, the second feedforward DC blocking injection capacitor 120, the first feedback DC blocking injection capacitor 1010, and the second feedback DC blocking injection capacitor 1020 are the same.

[0039] It should be noted that the capacitance values ​​of the first feedforward DC blocking injection capacitor 110, the second feedforward DC blocking injection capacitor 120, the first feedback DC blocking injection capacitor 1010, and the second feedback DC blocking injection capacitor 1020 are kept consistent. This can unify the component selection standard, simplify the circuit structure, further enhance the symmetry characteristics of the main circuit, and improve the working stability of the active electromagnetic interference filter.

[0040] In one possible implementation, the signal processing circuit generates feedforward compensation signals and feedback compensation signals with different amplification factors through the operational amplifier 700.

[0041] It should be noted that the signal processing circuit relies on a single operational amplifier 700, and by combining the parameter ratios of the feedforward amplification impedance component 600 and the feedback amplification impedance 800, it can generate feedforward compensation signals and feedback compensation signals with different amplification factors. No additional amplification devices are required, which realizes the multiplexing of the injection loop and the amplification circuit, simplifies the circuit structure and reduces hardware costs.

[0042] In one possible implementation, based on the first formula, the feedforward amplification impedance component 600 in the signal processing circuit, the sampling resistor 400 in the current sampling circuit, the primary winding component 500 of the current transformer, the secondary winding component 300 of the current transformer, and the feedforward DC blocking injection capacitor component 100 and the feedforward injection impedance 200 in the coupling injection branch are adjusted so that the equivalent impedance of the feedforward injection part is approximately 0, thereby improving the filtering effect of common-mode electromagnetic interference. The first formula is:

[0043] in, The equivalent impedance of the feedforward injection section. This is the equivalent impedance of a linear impedance-stabilized network. For feedforward injection impedance, The impedance of the feedforward DC blocking injection capacitor. This is the second feedforward amplification impedance. The first feedforward amplification impedance, For sampling resistor, This represents the turns ratio of the current transformer.

[0044] It should be noted that by adjusting the parameters of the feedforward amplification impedance component 600, sampling resistor 400, current transformer primary winding component 500, current transformer secondary winding 300, feedforward DC blocking injection capacitor component 100, and feedforward injection impedance 200, the equivalent impedance of the feedforward injection part can be made approximately zero, allowing the feedforward compensation signal to be injected into the main circuit without loss, thereby maximizing the filtering and attenuation effect of common-mode electromagnetic interference.

[0045] Furthermore, such as Figure 2 The equivalent circuit shown can be used to calculate the voltage at each node. The voltage signal obtained from the current sampling is shown in the following formula, where V RCT For the sampled voltage signal, the inductive impedance is greater than the resistive impedance in the conducted noise frequency band, therefore a certain approximation can be made:

[0046] Based on the impedance of the operational amplifier signal processing circuit and the sampled voltage signal, the expression for the feedforward injection voltage can be obtained:

[0047] The equivalent impedance of the feedforward bus to ground is shown in the following equation, where I AEF Z represents the current passing through the feedforward branch. C1 The parallel impedance of the DC blocking injection capacitor C1 allows the capacitor to perform a certain differential-mode filtering function.

[0048] The common-mode noise current flowing into the LISN can be further calculated using the equivalent impedance, as shown in the following equation, where I... LISN The common-mode noise current flowing through the LISN:

[0049] Therefore, the equivalent impedance of the feedforward branch can be obtained:

[0050] when and When the current approaches, the equivalent impedance of the active filter approaches 0, and the current feedforward can effectively suppress the transmission of conducted common-mode noise current.

[0051] In one possible implementation, based on the second formula, the feedforward DC blocking injection capacitor component 100 and feedforward injection impedance 200 of the coupling injection branch, the sampling resistor 400, the primary winding component 500 and the secondary winding 300 of the current transformer in the current sampling circuit, and the feedforward amplification impedance component 600, the feedback amplification impedance 800 and the operational amplifier 700 of the signal processing circuit are adjusted to achieve operational amplifier outputs with different amplification factors, thereby improving the suppression effect on common-mode noise. The second formula is:

[0052] in, This is the compensation signal voltage output by the operational amplifier. This is the second feedforward amplification impedance. The first feedforward amplification impedance, The turns ratio of the current transformer. For sampling resistor, For feedback amplification impedance, The impedance of the feedforward DC blocking injection capacitor. For feedforward injection impedance, The common-mode noise current of the main circuit. This is the common-mode noise voltage of the main circuit.

[0053] It should be noted that by coordinating and adjusting the parameters of each component in the coupling injection branch, current sampling circuit, and signal processing circuit, the output amplification factor of the operational amplifier 700 can be flexibly adjusted to adapt to common-mode noise of different frequency bands and intensities, thereby achieving full-band, wide-range common-mode electromagnetic interference suppression and meeting the electromagnetic compatibility requirements of various power electronic devices.

[0054] Furthermore, the output voltage of the op-amp can be derived. Given the voltage of the feedforward node, the output voltage of the op-amp can be calculated:

[0055] The calculated op-amp output voltage is:

[0056] Therefore, we can obtain:

[0057] The output voltage is an inverted amplification of the noise current and noise voltage signals, thereby further attenuating the noise and allowing the common-mode noise amplitude to pass through strict EMC limits. Simultaneously, the injection impedance and signal processing branch can be adjusted to obtain different common-mode noise suppression effects.

[0058] Furthermore, such as Figure 3 As shown, a typical application scenario of a front-feedback integrated AEF with injection loop multiplexing is presented. In this circuit, the power electronic converter (EUT) is the noise source. In scenarios with high noise levels, an additional passive filter can be added to the EUT side for preliminary filtering to prevent saturation of the active filter. The proposed front-feedback integrated AEF with injection loop multiplexing is placed close to the LISN side, which is used to detect common-mode noise.

[0059] With the noise source and noise source impedance being the same, a comparison of the spectrum of a front-feedback integrated AEF with injection loop multiplexing enabled and a front-feedback integrated AEF without injection loop multiplexing enabled is shown below. Figures 4-5 As shown, where, Figure 4 To prevent the common-mode noise spectrum of the front-feedback integrated AEF from enabling the injection loop multiplexing of this application, Figure 5The common-mode noise spectrum of the front-feedback integrated AEF with injection loop multiplexing in this application is shown. It can be clearly seen that the front-feedback integrated AEF with injection loop multiplexing in this application has a large suppression of common-mode noise.

[0060] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0061] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0062] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0063] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0064] In the description of this specification, references to terms such as "one possible implementation," "further," "exemplary," "specific example," or "optional," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. The illustrative expressions of the above terms in this specification do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0065] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention filed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not claimed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the appended claims.

Claims

1. A feedforward integrated AEF for injection loop multiplexing, characterized by, include: The current sampling circuit is used to collect the common-mode noise current of the main circuit and convert it into a sampling voltage signal; The signal processing circuit, with its input terminal coupled to the output terminal of the current sampling circuit, generates both a feedforward compensation signal and a feedback compensation signal simultaneously through a single operational amplifier. These signals are used to amplify the sampled voltage signal and generate the compensation signal. The coupling injection branch is connected to the feedforward injection node of the main circuit and is used to inject the compensation signal into the main circuit in a feedforward manner. The feedback injection branch is connected to the feedback injection node of the main circuit and is used to inject the compensation signal into the main circuit in a feedback manner.

2. The feedforward integrated AEF for injection loop multiplexing of claim 1, wherein, The current sampling circuit includes a primary winding assembly of a current transformer, a secondary winding of a current transformer, and a sampling resistor. The primary winding assembly of the current transformer includes a first primary winding and a second primary winding, which are connected in series in the positive and negative busbars of the main circuit, respectively, and are located between the feedforward injection node and the feedback injection node. The secondary winding of the current transformer is connected in parallel with the sampling resistor and magnetically coupled to the primary winding assembly of the current transformer, converting the coupled common-mode noise current into a voltage signal.

3. The pre-feedback integrated AEF with injection loop multiplexing according to claim 2, characterized in that, The signal processing circuit includes a feedforward amplification impedance component, a feedback amplification impedance, and an operational amplifier. The feedforward amplification impedance assembly includes a first feedforward amplification impedance and a second feedforward amplification impedance; one end of the first feedforward amplification impedance is connected to the output terminal of the current sampling circuit, and the other end is connected to the inverting input terminal of the operational amplifier; one end of the second feedforward amplification impedance is connected to the inverting input terminal of the operational amplifier, and the other end is connected to the coupling injection branch, with the connection node being the first node; The feedback amplification impedance is connected between the first node and the output of the operational amplifier. The non-inverting input of the operational amplifier is grounded.

4. The pre-feedback integrated AEF with injection loop multiplexing according to claim 3, characterized in that, The coupled injection branch includes a feedforward DC blocking injection capacitor assembly and a feedforward injection impedance; The feedforward DC blocking injection capacitor assembly includes a first feedforward DC blocking injection capacitor and a second feedforward DC blocking injection capacitor, which are connected in series with the positive and negative busbars near the LISN side, respectively, and the common midpoint of the two is the feedforward injection node. The feedforward injection impedance is connected in series between the first node and the feedforward injection node.

5. The pre-feedback integrated AEF with injection loop multiplexing according to claim 4, characterized in that, The feedback injection branch includes a feedback injection impedance and a feedback DC blocking injection capacitor assembly; The feedback DC blocking injection capacitor assembly includes a first feedback DC blocking injection capacitor and a second feedback DC blocking injection capacitor, which are connected in series with the positive and negative busbars near the EUT side, respectively, and the common midpoint of the two is the feedback injection node. The feedback injection impedance is connected in series between the output of the operational amplifier and the feedback injection node.

6. The pre-feedback integrated AEF with injection loop multiplexing according to claim 5, characterized in that, The first feedforward DC blocking injection capacitor has the same capacitance value as the second feedforward DC blocking injection capacitor, and the first feedback DC blocking injection capacitor has the same capacitance value as the second feedback DC blocking injection capacitor.

7. The pre-feedback integrated AEF with injection loop multiplexing according to claim 6, characterized in that, The capacitance values ​​of the first feedforward DC blocking injection capacitor, the second feedforward DC blocking injection capacitor, the first feedback DC blocking injection capacitor, and the second feedback DC blocking injection capacitor are the same.

8. The pre-feedback integrated AEF with injection loop multiplexing according to claim 3, characterized in that, The signal processing circuit generates feedforward compensation signals and feedback compensation signals with different amplification factors through the operational amplifier.

9. The pre-feedback integrated AEF with injection loop multiplexing according to claim 1, characterized in that, Based on the first formula, the feedforward amplification impedance component in the signal processing circuit, the sampling resistor in the current sampling circuit, the primary winding component of the current transformer, the secondary winding of the current transformer, and the feedforward DC blocking injection capacitor component and feedforward injection impedance in the coupling injection branch are adjusted so that the equivalent impedance of the feedforward injection part is approximately 0, thereby improving the filtering effect of common-mode electromagnetic interference. The first formula is: in, The equivalent impedance of the feedforward injection section. This is the equivalent impedance of a linear impedance-stabilized network. For feedforward injection impedance, The impedance of the feedforward DC blocking injection capacitor. This is the second feedforward amplification impedance. The first feedforward amplification impedance, For sampling resistor, This represents the turns ratio of the current transformer.

10. The pre-feedback integrated AEF with injection loop multiplexing according to claim 1, characterized in that, Based on the second formula, the feedforward DC blocking injection capacitor component and feedforward injection impedance of the coupling injection branch, the sampling resistor, the primary winding component and the secondary winding of the current transformer in the current sampling circuit, the feedforward amplification impedance component, the feedback amplification impedance and the operational amplifier in the signal processing circuit are adjusted to achieve operational amplifier outputs with different amplification factors and improve the suppression effect of common-mode noise. The second formula is: in, This is the compensation signal voltage output by the operational amplifier. This is the second feedforward amplification impedance. The first feedforward amplification impedance, The turns ratio of the current transformer. For sampling resistor, For feedback amplification impedance, The impedance of the feedforward DC blocking injection capacitor. For feedforward injection impedance, The common-mode noise current of the main circuit. This is the common-mode noise voltage of the main circuit.

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