Active combined filter for electromagnetic interference blocking

Abstract

The invention discloses an active combined filter for electromagnetic interference blocking. The active combined filter comprises a common mode inductor, a differential mode inductor, a rectifier bridge, a BOOST inductor, a rectifier diode, a capacitor and an MOS tube. The input end of the common-mode inductor is connected with a power supply, the output end of the common-mode inductor is electrically connected with the differential-mode inductor, the differential-mode inductor is electrically connected with the rectifier bridge, the rectifier bridge is electrically connected with the BOOST inductor, and the BOOST inductor is electrically connected with the rectifier diode and the capacitor in sequence; and an MOS tube is connected in series between the BOOST inductor and the ground. According to the scheme provided by the invention, an external power supply enters the rectifier bridge after passing through the common mode inductor and the differential mode inductor, the rectifier bridge converts sinusoidal alternating current into pulsating direct current, and the pulsating direct current is converted into 380V direct current after passing through the boost electricity of the BOOST boost inductor, the rectifier diode and the capacitor.

Description

Technical Field

[0001] This application relates to the technical field of filters, and particularly to an active combined filter for electromagnetic interference blocking. Background Art

[0002] Most related electronic devices need to conduct CE101 and CE102 susceptibility conduction experiments in GJB151B-2013 (Requirements and Measurements for Electromagnetic Emission and Susceptibility of Military Equipment and Subsystems) during electromagnetic compatibility experiments. Especially when 220V / 50Hz switching power supply products conduct CE101 susceptibility conduction experiments, odd harmonics will seriously exceed the standard. Along with the exceeding of CE101, RE101 (25Hz 10kHz magnetic field radiation emission) usually also exceeds the standard. The exceeding of these two items will seriously affect the normal operation of other electronic devices.

[0003] Currently, traditional harmonic suppression technologies often use passive filtering methods for harmonic suppression. However, in principle, a passive filter shorts fixed-order harmonics and consumes the energy of specific-order harmonics. When there are multiple exceeded harmonics, multiple harmonic suppression circuits are required. The disadvantage of this method is that the overall efficiency of the circuit is relatively low, and the filter is large in volume, heavy in weight, and generates a large amount of heat.

[0004] To solve the problem of exceeded harmonics and at the same time solve the disadvantages of passive harmonic suppression filters, a power factor correction circuit is used during harmonic suppression. This can improve efficiency, and at the same time, the input current tracks the input voltage, reducing the energy of each harmonic and achieving the effect of harmonic suppression.

[0005] However, after using the power factor correction circuit, it will cause serious exceeding of the standard in the 10K-200MHz frequency band of the CE102 susceptibility conduction experiment, and still cannot effectively pass the electromagnetic compatibility experiment. Therefore, it is necessary to design a filter with a smaller volume, higher efficiency, and at the same time, it can solve the problem of exceeding the standard in the CE101 and CE102 standard experiments. Summary of the Invention

[0006] In view of the above problems, this application provides an active combined filter for electromagnetic interference blocking, which can solve the problem of exceeding the standard of CE101 and CE102 power line conduction emissions while meeting the requirements of miniaturization.

[0007] To solve the above technical problems, this application proposes an active combined filter for electromagnetic interference blocking, including a common-mode inductor, a differential-mode inductor, a rectifier bridge, a BOOST boost inductor, a rectifier diode, a capacitor, and a MOS transistor; The input end of the common-mode inductor is connected to a power supply. The output end of the common-mode inductor is electrically connected to the differential-mode inductor. The differential-mode inductor is electrically connected to the rectifier bridge. The rectifier bridge is electrically connected to the BOOST boost inductor. The BOOST boost inductor is sequentially electrically connected to the rectifier diode and the capacitor. A MOS transistor is connected in series between the BOOST boost inductor and the ground.

[0008] In the technical solution of the embodiment of the present application, an external power supply enters the rectifier bridge after passing through the common-mode inductor and the differential-mode inductor. The rectifier bridge converts the sinusoidal alternating current into a pulsating direct current. After the pulsating direct current is boosted by the BOOST boost inductor, rectified by the rectifier diode, and filtered by the capacitor, the pulsating direct current is converted into a DC 380V.

[0009] In the process of boosting the pulsating direct current to 380V direct current, by tracking the waveforms of the input voltage and the output voltage, and simultaneously controlling the on and off of the MOS transistor, the waveform of the input current is made to track the waveform of the input voltage under the action of the BOOST boost inductor, so that the entire load is purely resistive. When the overall filter is purely resistive, the harmonic interference of the load will become very small, thus achieving the purpose of suppressing harmonics. At the same time, on the premise of meeting the CE101 test, it is necessary to suppress the CE102 over-standard frequency band. At this time, the common-mode inductor effectively suppresses the common-mode interference generated by the subsequent equipment, and the differential-mode inductor suppresses the differential-mode interference generated by the subsequent equipment. After combination, it can effectively suppress the interference signals in the range of 10K - 30MHz, so that the overall filter meets the CE101 and CE102 tests in the electromagnetic compatibility experiment.

[0010] In some embodiments, the active combined filter for electromagnetic interference blocking further includes a current detection module, which is electrically connected to the BOOST boost inductor and is used to detect the current in the BOOST boost inductor.

[0011] In some embodiments, the current detection module includes a current transformer, which is electrically connected to the BOOST boost inductor.

[0012] In some embodiments, the active combined filter for electromagnetic interference blocking further includes a control chip. The current transformer and the MOS transistor are respectively electrically connected to the control chip.

[0013] In some embodiments, it further includes a MOS transistor control module, which is connected in series between the control chip and the MOS transistor.

[0014] In some embodiments, the capacitor includes C8, C3, and C2. The direct current output by the rectifier diode is electrically connected to the positive electrodes of C8, C3, and C2 respectively.

[0015] In some embodiments, a power supply module is further included, and the power supply module is electrically connected to the control chip.

[0016] The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present application more obvious and understandable, the following specific embodiments of the present application are specifically exemplified. Description of the Drawings

[0017] By reading the detailed description of the following embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the embodiments and are not considered to be a limitation of the present application. And in all the drawings, the same reference numerals are used to represent the same components. In the drawings: Figure 1 Schematic diagram of an active combined filter for electromagnetic interference blocking provided by some embodiments of the present application; Figure 2 Schematic diagram of a passive high-frequency suppression circuit provided by some embodiments of the present application; Figure 3 Active input rectifier circuit provided by some embodiments of the present application; Figure 4 Partial schematic diagram of the A-channel boost circuit provided by some embodiments of the present application; Figure 5 Partial schematic diagram of the B-channel boost circuit provided by some embodiments of the present application; Figure 6 Partial schematic diagram of the A-channel current acquisition and processing provided by some embodiments of the present application; Figure 7 Partial schematic diagram of the B-channel current acquisition and processing provided by some embodiments of the present application; Figure 8 Partial schematic diagram of the output capacitor provided by some embodiments of the present application; Figure 9 Partial schematic diagram of the interface circuit provided by some embodiments of the present application; Figure 10 Partial schematic diagram of the power supply for the control battery core provided by some embodiments of the present application; Figure 11 Schematic diagram of the control battery core provided by some embodiments of the present application; Figure 12 Partial schematic diagram of the MOS transistor drive circuit provided by some embodiments of the present application. Detailed Embodiments

[0018] The embodiments of the technical solution of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and thus are only examples and cannot be used to limit the protection scope of the present application.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the description of the specification, claims and drawings of this application are intended to cover non-exclusive inclusion.

[0020] In the description of the embodiments of this application, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary-secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "a plurality" is more than two, unless otherwise specifically defined.

[0021] Referring to "embodiments" herein means that the specific features, structures or characteristics described in connection with the embodiments may be included in at least one embodiment of this application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein may be combined with other embodiments.

[0022] In the description of the embodiments of this application, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after.

[0023] In the description of the embodiments of this application, the term "a plurality" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0024] In the description of the embodiments of the present application, the orientation or positional relationship indicated by technical terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the embodiments of the present application.

[0025] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installation", "connection", "connection", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can also be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0026] As Figure 1 shown, the present application provides an active combined filter for electromagnetic interference blocking. The active combined filter includes a common-mode inductor 10, a differential-mode inductor 11, a rectifier bridge 12, a BOOST boost inductor 13, a rectifier diode 14, a capacitor 15, and a MOS transistor 16. Among them, the input end of the common-mode inductor 10 is connected to the power supply, the output end of the common-mode inductor 10 is electrically connected to the differential-mode inductor 11, the differential-mode inductor 11 is electrically connected to the rectifier bridge 12, the rectifier bridge 12 is electrically connected to the BOOST boost inductor 13, and the BOOST boost inductor 13 is electrically connected to the rectifier diode 14 and the capacitor 15 in sequence; a MOS transistor 16 is connected in series between the BOOST boost inductor 13 and the ground.

[0027] The active combined filter is mainly composed of two parts. One part is a passive circuit composed of inductors and capacitors, which can suppress interference signals of 10K - 30MHz. The other part is an active circuit, which can make the input current waveform track the input voltage waveform, thereby realizing the suppression of harmonic interference. After the two parts are combined, it can meet the test requirements of CE101 and CE102 in the GJB151B-2013 electromagnetic compatibility experiment.

[0028] The specific working process is as follows: The commercial power supply AC220V enters the rectifier bridge 12 of the active circuit part after being suppressed by the passive common-mode inductor 10 and the passive differential-mode inductor 11. The rectifier bridge 12 converts the sinusoidal alternating current into pulsating direct current. After passing through the BOOST boost inductor 13, the output rectifier diode D14, and the output capacitor 15, the pulsating direct current is converted into DC 380V.

[0029] During the process of raising the pulsating direct current to 380V direct current, the control cell controls the MOS transistor 16 to conduct and turn off by tracking the waveforms of the input voltage and the output voltage. With the cooperation of the BOOST boost inductor 13, the waveform of the input current tracks the waveform of the input voltage, thereby making the entire load system present a pure resistive property. When the system is pure resistive, the harmonic interference of the load will become very small, achieving the purpose of suppressing harmonics, and further meeting the purpose of the CE101 test in the electromagnetic compatibility experiment of GJB151B-2013 (Electromagnetic Emission and Sensitivity Requirements and Measurements for Military Equipment and Subsystems).

[0030] However, during the process of harmonic suppression, due to the rapid opening and closing of the MOS transistor 16, interference will be generated in the input circuit at the switching frequency position of the MOS transistor 16 and at the high-order resonance frequency points of the switching frequency, thus causing the CE102 test in the electromagnetic compatibility experiment of GJB151B-2013 (Electromagnetic Emission and Sensitivity Requirements and Measurements for Military Equipment and Subsystems) to exceed the standard.

[0031] To enable the entire system to simultaneously meet the CE101 and CE102 tests in the electromagnetic compatibility experiment of GJB151B-2013 (Electromagnetic Emission and Sensitivity Requirements and Measurements for Military Equipment and Subsystems), it is necessary to suppress the CE102 over-standard frequency band on the premise of meeting the CE101 test. At this time, the passive filtering part is required. The passive filtering part consists of the common-mode inductor 10 and the differential-mode inductor 11. The common-mode inductor 10 effectively suppresses the common-mode interference generated by the subsequent equipment, and the differential-mode inductor 11 suppresses the differential-mode interference generated by the subsequent equipment. After combination, it can effectively suppress the interference signals of 10K - 30MHz, making the entire system meet the CE101 and CE102 tests in the electromagnetic compatibility experiment of GJB151B-2013.

[0032] To make the content and advantages of the present invention more prominent, the following will be described from the working principle.

[0033] Refer to Figure 2As shown, the common-mode inductor 10 is partially composed of capacitors L1 / CY1 / CY2 / CY3 / CY4. The inductor L1 is wound with an amorphous magnetic core, and its common-mode inductance can reach 7 - 8mH. The differential-mode leakage inductance is very small, only dozens of microhenries. According to formula 2, for an inductive circuit, the smaller the frequency, the smaller the impedance. Therefore, when the interference frequency is relatively high, due to the relatively large common-mode inductance, the common-mode impedance is also relatively large, which can effectively suppress the transmission of common-mode interference outward.

[0034] Since the mains power is a differential-mode type of signal, because the differential-mode leakage inductance is very small and the operating frequency of the mains power is relatively low, the differential-mode impedance is also relatively small. Therefore, it has no impact on the mains supply voltage. For the common-mode capacitors CY1 / CY2 / CY3 / CY4, according to formula 1, for a capacitive circuit, the higher the frequency, the smaller the impedance. When the interference frequency is relatively high, it can effectively bypass the common-mode interference and suppress the transmission of common-mode interference outward.

[0035] ZC = 1 / 2πfC Formula 1 ZL = 2πfL Formula 2 Refer to Figure 2 As shown, the differential-mode inductor 11 is partially composed of CX1 / CX2 / L2 / L3. According to formula 1, for a capacitive impedance, the higher the frequency, the smaller the impedance. If it is differential-mode interference, when the interference frequency is relatively large, the impedance on the differential-mode capacitors CX1 / CX2 is relatively small. Therefore, the differential-mode interference can be short-circuited. The differential-mode inductors L2 / L3 are wound with iron powder core magnetic cores, and the inductance is approximately 250µH. According to formula 2, for an inductive circuit, the smaller the frequency, the smaller the impedance. Therefore, for the operating frequency of the mains power, the impedance is very small and it can pass through with almost no loss. However, for the interference signal, due to the relatively high frequency, the impedance is also relatively large, so the interference signal is quickly attenuated.

[0036] Through the combination of the common-mode inductor 10 and the differential-mode inductor 11, the interference signals of 10K - 30MHZ generated by the subsequent harmonic suppression circuit and the load device can be effectively suppressed.

[0037] Figure 3 For the active part of the AC input terminal, the 220V 50Hz alternating current input from the connector J2 first passes through the fuse F1 and then enters the rectifier bridge D3. The alternating current after passing through the rectifier bridge will become pulsating direct current, and the output of the pulsating direct current is the network label VIN.

[0038] According to some embodiments of the present application, the active combined filter for electromagnetic interference blocking further includes a current detection module. The current detection module is electrically connected to the BOOST boost inductor 13 and is used to detect the current in the BOOST boost inductor 13.

[0039] According to some embodiments of the present application, the current detection module includes a current transformer, and the current transformer is electrically connected to the BOOST boost inductor 13.

[0040] Reference Figure 4 and Figure 5 as shown Figure 4 and Figure 5 are two BOOST boost circuits. These two boost circuits operate in an interleaved state. The advantage of this operating mode is that the input current also operates in an interleaved state, which can greatly reduce the ripple of the input current. The operating modes of the two circuits are the same. PWM waves are provided to Q1 or Q2 through GDAO or GDBO to control the conduction and cutoff of Q1 or Q2, and then inductors L1 and L2 are charged. After the inductors are charged, Q1 or Q2 is turned off. Since the inductor current does not change suddenly, the inductor will continue to supply power outward. After the output rectifier diode raises the output voltage to 380 VDC, it is output to VOUT. Two current transformers T1 and T2 detect the currents of the two boost circuits to prevent circuit damage caused by overload.

[0041] Figure 6 and Figure 7 are two current sampling circuits. The currents collected by current transformers T1 or T2 are converted into voltage signals through sampling resistors R5 or R22, and the sampled current signals are transmitted to the control chip through CSA or CSB. In Figure 6, R1, D5, R2, D6, and C5 together constitute the A-channel current falling-edge synthesis circuit. The current falling-edge synthesis circuit enables the circuit to still have a high harmonic suppression ability under light load. Similarly Figure 7 in, R18, D9, R19, D10, and C10 are also falling-edge synthesis circuits, which have the same effect in the B circuit.

[0042] According to some embodiments of the present application, the active combined filter for electromagnetic interference blocking further includes a control chip, and the current transformer and MOS transistor 16 are electrically connected to the control chip respectively.

[0043] According to some embodiments of the present application, it further includes a MOS transistor control module, and the MOS transistor control module is connected in series between the control chip and the MOS transistor 16.

[0044] According to some embodiments of the present application, the capacitor 15 includes C8, C3, and C2, and the direct current output by the rectifier diode 14 is electrically connected to the positive electrodes of C8, C3, and C2 respectively.

[0045] Figure 8 is the output capacitor circuit. The output direct current VOUT is connected to the C8, C3+, and C2+ terminals, which can make the output direct current more stable and play a function of output voltage regulation.

[0046] According to some embodiments of the present application, it further includes a power supply module, and the power supply module is electrically connected to the control chip.

[0047] Figure 9 To control the interface part between the battery cell and the drive voltage stabilization circuit, the input voltage VIN, output voltage VOUT, current detection signals CSA and CSB, and the control signals GDAO and GDBO of Q1 and Q2 of the drive voltage stabilization circuit are all connected through this interface circuit.

[0048] Figure 10 It is the power supply part circuit. The power supply part uses the AC / DC voltage stabilization module U1 to convert the output VOUT into 15VDC. After passing through R38 and D15, 15V is converted into 13V, and the 13V DC power is output to the control chip of the control board to supply power to the control chip.

[0049] Figure 11 It is the control part circuit. The control of the battery cell mainly revolves around the control chip U2. The control chip will track the input voltage and output voltage, and at the same time monitor the currents of channel A and channel B. By comprehensively calculating the input voltage, output voltage, current of channel A, and current of channel B, it controls GDAO and GDBO, and controls the on and off of the field effect transistors Q1 and Q2, so that the input current waveform tracks the waveform of the input voltage, and at the same time controls the output voltage to be a stable 380VDC.

[0050] Figure 12 It is the gate drive circuit of the field effect transistor. The driving ability of the PWM drive signal output by the control chip is limited and cannot quickly turn on or off the field effect transistor. Therefore, a drive chip is needed. U1 will output the PWM drive signal of the field effect transistor output by the control chip Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be covered by the scope of the claims and the description of the present application. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions that fall within the scope of the claims.

Claims

1. An active combined filter for electromagnetic interference blocking, characterized in that: It includes a common mode inductor (10), a differential mode inductor (11), a rectifier bridge (12), a BOOST inductor (13), a rectifier diode (14), a capacitor (15) and a MOS tube (16); The input end of the common-mode inductor (10) is connected to a power supply, the output end of the common-mode inductor (10) is electrically connected to the differential-mode inductor (11), the differential-mode inductor (11) is electrically connected to the rectifier bridge (12), the rectifier bridge (12) is electrically connected to the BOOST boost inductor (13), and the BOOST boost inductor (13) is electrically connected to the rectifier diode (14) and the capacitor (15) in sequence; A MOS tube (16) is connected in series between the BOOST inductor (13) and the ground.

2. The active combined filter for electromagnetic interference blocking according to claim 1, characterized in that: The active combined filter for electromagnetic interference blocking further comprises a current detection module, wherein the current detection module is electrically connected to the BOOST boost inductor (13) and is used to detect the current in the BOOST boost inductor (13).

3. The active combined filter for electromagnetic interference blocking according to claim 2, characterized in that: The current detection module comprises a current transformer, and the current transformer is electrically connected to the BOOST boost inductor (13).

4. The active combined filter for electromagnetic interference blocking according to claim 3, characterized in that: The active combined filter for electromagnetic interference blocking also includes a control chip, and the current transformer and the MOS tube (16) are respectively electrically connected to the control chip.

5. The active combined filter for electromagnetic interference blocking according to claim 4, characterized in that: It also includes a MOS tube control module, which is connected in series between the control chip and the MOS tube (16).

6. The active combined filter for electromagnetic interference blocking according to any one of claims 1 to 5, characterized in that: The capacitor (15) includes C8, C3 and C2, and the direct current output by the rectifier diode (14) is electrically connected to the positive electrodes of C8, C3 and C2 respectively.

7. The active combined filter for electromagnetic interference blocking according to claim 4, characterized in that: It also includes a power supply module, which is electrically connected to the control chip.

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