Radioactive noise reduction device for compensating for electromagnetic interference

Abstract

According to an embodiment of the present invention, provided is a radioactive noise reduction device for compensating for electromagnetic interference generated by a radioactive source, the radioactive noise reduction device comprising: a compensation unit which includes a compensation loop through which all or a portion of radioactive noise emitted from the source passes; and a circuit unit which is connected to the compensation unit and includes one or more inductors and one or more amplification units. As an impedance of the circuit unit, an input impedance (Zin) viewed from the compensation unit is a value obtained by negatively converting the impedance of the compensation unit.

Description

Radiation noise reduction device to compensate for electromagnetic interference

[0001] The following embodiments relate to an active radiation noise reduction device for compensating for electromagnetic interference generated by a radiation source.

[0002] Recent demands for smaller, faster processing power, and lower power consumption in home appliances, industrial electronics, and information and communication devices have led to increasingly smaller and more sophisticated circuits. Consequently, more circuits are being installed in confined spaces, making them increasingly susceptible to electromagnetic signals or electrical noise (electromagnetic noise). This unwanted electromagnetic noise, which disrupts the operation of other devices or systems, is called electromagnetic interference (EMI).

[0003] Electromagnetic noise, which causes electromagnetic interference, can be classified into conductive and radiated noise depending on the transmission path. Conductive noise refers to electromagnetic noise transmitted through electrical circuits, such as wires or cables. In contrast, radiated noise refers to electromagnetic waves that propagate wirelessly through air or other media, affecting other devices. This radiated noise is not only harmful to the human body, but can also cause malfunctions or failures in other connected electronic devices. In particular, low-frequency radiated noise is classified as a possible human carcinogen and is regulated under electromagnetic wave standards.

[0004] Meanwhile, Wireless Power Transfer (WPT) or Induction Heating (IH) systems are technologies that wirelessly transfer power through space without wires. Wireless power transfer operates by transmitting electrical energy using electromagnetic waves or magnetic fields, rather than using electrical wires, to power electronic devices. Wireless power transfer and induction heating fundamentally operate on the principle of magnetic resonance or induced current, which can be achieved by electromagnetic wave principles for direct energy transfer. Both wireless power transfer and induction heating technologies inevitably require the coil to be exposed outside the enclosure for efficient power transfer, and this structure becomes a major source of radioactive emissions.

[0005]

[0006] The object of the present invention is to provide an active radiation noise reduction device for compensating for electromagnetic interference generated by a radiation source.

[0007] The problems addressed by the present invention are not limited to those mentioned above. Other problems and advantages of the present invention not mentioned above can be understood through the following description and will be more clearly understood through the embodiments of the present invention. Furthermore, it will be appreciated that the problems and advantages addressed by the present invention can be realized by the means and combinations thereof set forth in the claims.

[0008] According to one embodiment of the present invention, a radiation noise reduction device for compensating for electromagnetic interference generated by a radiation source source is provided, comprising: a compensation unit including a compensation loop through which all or part of radiation noise emitted from the source source passes; a circuit unit connected to the compensation unit and including one or more inductors and one or more amplifiers; and an input impedance (Zin) of the circuit unit is a value obtained by converting the impedance of the compensation unit into a negative value.

[0009] In the present invention, the compensation loop may be provided in a form that partially or completely surrounds the radioactive source source so that at least a portion of the radioactive noise emitted from the source source can pass through a flat or three-dimensional space inside the loop formed by the compensation loop.

[0010] In the present invention, the radiation noise reduction device may be positioned on the same circuit board as the source source, and the compensation loop may be provided in a form that surrounds the radiation source source.

[0011] In the present invention, the current flowing in the compensation section may be a current that generates a canceling magnetic field having a direction opposite to that of the radiant noise passing through the compensation loop.

[0012] In the present invention, the circuit unit may include a target unit including one or more inductors; an amplification unit connecting the compensation unit and the target unit and including one or more amplifiers;

[0013] In the present invention, the amplification unit includes two Op-amps, and the positive input terminals of the two Op-amps are respectively connected to both ends of the target unit, and the negative input terminals are respectively connected to both ends of the compensation unit, and the input impedance (Zin) can be calculated based on the resistances (Rf1, Rf2) connected to the input terminals of the Op-amps and the impedance (Zt) of the target unit.

[0014] In the present invention, the positive input terminals of the two Op-amps are connected to the target unit and the first resistor (Rf1), the negative input terminals are connected to the compensation unit and the second resistor (Rf2), the output terminals are connected to the first resistor (Rf1) and the second resistor (Rf2), and the input impedance (Zin) may be Zin=-(Rf2 / Rf1)*Zt.

[0015] In the present invention, the amplifying section includes one Op-amp, and the positive input terminal of the Op-amp is connected to one end of the target section and one end of the compensation section, the negative input terminal of the Op-amp is connected to the first on-resistance (Z1) and the second on-resistance (Z2), and the output terminal of the Op-amp is connected to the first on-resistance (Z1) and the other end of the target section, when the input impedance (Zin) can be Zin=-(Z1 / Z2)*Zt.

[0016] In the present invention, the compensation unit of the radiation noise reduction device may be provided so that all or part of the radiation noise emitted from either the transmitting end (Rx) coil or the receiving end (Rx) coil of the wireless power transmission system passes through.

[0017]

[0018] According to one embodiment of the present invention, electromagnetic interference generated by a radioactive source can be actively compensated for.

[0019] Additionally, according to one embodiment of the present invention, a device capable of canceling out radiation noise generated by a radioactive source can be provided.

[0020] Additionally, according to one embodiment of the present invention, a circuit including a negative impedance converter and generating a compensating magnetic field that compensates for an external magnetic field may be provided.

[0021] FIG. 1 illustrates a radioactive source emitting radioactive noise according to one embodiment of the present invention.

[0022] FIG. 2 is a drawing showing an active radiation noise reduction device according to one embodiment of the present invention.

[0023] FIG. 3 illustrates the operation of a radiation noise reduction device and a radiation source according to one embodiment of the present invention.

[0024] FIGS. 4A to 6B are drawings showing an active radiation noise reduction device according to another embodiment of the present invention.

[0025] Fig. 7 is a block diagram showing a radiation noise reduction device according to one embodiment.

[0026] Figures 8 and 9 illustrate a radiation noise reduction device according to the first embodiment of the present invention.

[0027] Figures 10 and 11 illustrate a radiation noise reduction device according to a second embodiment of the present invention.

[0028] Figures 12 and 13 illustrate a radiation noise reduction device according to a third embodiment of the present invention.

[0029] Figure 14 is an example of using a shielding structure to reduce radiation noise.

[0030] FIG. 15 and FIG. 16 are drawings illustrating a radiation noise reduction device according to one embodiment of the present invention applied to a wireless power transmission system.

[0031] Figures 17A and 17B are examples of a radiation noise reduction device according to one embodiment of the present invention applied to an actual product.

[0032] The advantages and features of the present invention, and the methods for achieving them, will become clearer with reference to the embodiments described in detail with the accompanying drawings. However, the present invention is not limited to the embodiments presented below, but can be implemented in various different forms, and it should be understood that all modifications, equivalents, and alternatives fall within the spirit and technical scope of the present invention.

[0033] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the terms “comprise” or “have” are intended to indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0034] Some embodiments of the present disclosure may be represented by functional block configurations and various processing steps. Some or all of these functional blocks may be implemented by various hardware and / or software configurations that perform specific functions. For example, the functional blocks of the present disclosure may be implemented by one or more microprocessors or by circuit configurations for a given function. Furthermore, for example, the functional blocks of the present disclosure may be implemented in various programming or scripting languages. The functional blocks may be implemented by algorithms that execute on one or more processors. Furthermore, the present disclosure may employ conventional techniques for electronic configuration, signal processing, and / or data processing. Terms such as “mechanism,” “element,” “means,” and “configuration” may be used broadly and are not limited to mechanical and physical configurations.

[0035] Additionally, the connecting lines or connecting members between components depicted in the drawings are merely exemplary representations of functional connections and / or physical or circuit connections. In an actual device, connections between components may be represented by various functional connections, physical connections, or circuit connections that may be replaced or added.

[0036] The present disclosure will be described in detail with reference to the attached drawings below.

[0037] FIG. 1 illustrates a radioactive source emitting radioactive noise according to one embodiment of the present invention.

[0038] Fig. 1 illustrates an example of a radioactive source (200) existing inside an electronic device (10). The radioactive source (200) includes a source current source (I) and can be said to be a noise source that generates radioactive noise when the electronic device (10) operates. Although in Fig. 1, the radioactive noise is indicated by a dotted arrow and is illustrated as being radiated from the source (200), it is not limited thereto and the radioactive noise may be emitted without a clear directivity in the vertical or horizontal direction.

[0039] These radiated emissions (RE) are commonly referred to as electromagnetic noise. As electronic devices become faster and more integrated, electromagnetic interference (EMI) caused by radiated noise is making it difficult to ship these devices.

[0040] Therefore, existing methods of physically shielding radioactive sources have been used to reduce radiation noise emissions. However, physical shielding methods have the disadvantage of failing to effectively block radioactive noise, especially low-frequency electromagnetic waves. Furthermore, these physical shielding methods are expensive and, due to the need for thick shielding materials to increase efficiency, face space constraints.

[0041] Accordingly, according to one embodiment of the present invention, a method for effectively compensating for electromagnetic interference using an active radiation noise reduction device can be proposed.

[0042] FIG. 2 is a drawing showing an active radiation noise reduction device according to one embodiment of the present invention.

[0043] Referring to FIG. 2, the radiation noise reduction device (100) may include at least one compensation loop (101) and a circuit portion (102). Although FIG. 2 illustrates that the compensation loop (101) according to one embodiment has a circular shape, in other embodiments, the compensation loop (101) may exist in various shapes as long as it forms a loop when points A and B are connected. For example, in the embodiment of FIG. 2, the number of turns of the compensation loop (101) is one, but in other embodiments, the number of turns of the compensation loop (101) may be multiple.

[0044] In addition, according to one embodiment of the present invention, the compensation loop (101) may be a loop through which all or part of the radiation noise emitted from the radiation source (200) of the electronic device (200) passes. More specifically, as described above with reference to FIG. 1, the radiation source (200) may generate radiation noise. At this time, according to one embodiment, a flat or three-dimensional space inside the loop formed by the compensation loop (101) may be formed such that at least part of the radiation noise emitted from the radiation source (200) passes therethrough.

[0045] According to a more specific embodiment, as illustrated in FIG. 2, the compensation loop (101) may be provided in a shape that surrounds part or all of the radioactive source source (200). That is, the radioactive source source (200) may be positioned inside the loop formed by the compensation loop (101) so that the compensation loop (101) may be provided in a shape that completely surrounds the radioactive source source (200). In this case, the radiation noise reduction device (100) can effectively cancel out radiation noises generated by the radioactive source source (200). Or, in another embodiment, according to another embodiment of the present invention, unlike FIG. 2, the inside of the loop formed by the compensation loop (101) may be in a shape that surrounds or covers only part of the radioactive source source (200).

[0046] FIG. 3a and FIG. 3b illustrate the operation of a radiation noise reduction device and a radiation source according to one embodiment of the present invention.

[0047] First, in the embodiments of FIGS. 3a and 3b, for convenience of explanation, the case in which the radioactive source (200) is located at the bottom in the three-dimensional space, the short-circuit loop (11) is located at the top in the case of FIG. 3a, and the radioactive noise reduction device (100) is located at the top in the case of FIG. 3b is exemplified.

[0048] According to a specific embodiment, FIGS. 3A and 3B illustrate that a radioactive source (200) includes a source loop (201) and is positioned on a lower plane, and a short-circuit loop (11) and a radiation noise reduction device (100) are positioned on an upper plane. The lower plane and the upper plane may be close to parallel, but are not necessarily limited thereto.

[0049] In addition, as seen in FIGS. 3a and 3b, the radiative source source (200) can be seen to have a source current (Isource) that flows clockwise when viewed from above, flowing along the source loop (201). In the present invention, for the convenience of explanation, the radiative source source (200) is illustrated as having a loop-shaped source loop (201) through which the source current (Isource) flows, and radiative noise that is radiated downwards in the direction of propagation of the source current (Isource) is generated (illustrated by a solid arrow pointing downward in FIGS. 3a and 3b). However, the emitted radiative noise is not limited to the examples shown in FIGS. 3a and 3b, and the radiative noise may be emitted in various directions depending on the shape of the radiative source source (200).

[0050] First, let's look at an embodiment in which a short loop (11) is formed at the top of a radioactive source source (200) as shown in FIG. 3a. According to one embodiment, the short loop (11) may be a wire loop having a loop inductance (L) based on points A and B. In addition, according to one embodiment, the source loop (11) may be a circuit in which points A and B are open and then shorted. That is, it is exemplified that points A and B of the source loop (11) are shorted while the radioactive source source (200) is positioned on the lower plane.

[0051] In this case, since a magnetic field is generated downward from the inside of the source loop (201) and the short loop (11) by the radioactive source source (200), an induced electromotive force (Vemf) may be generated between points A and B of the short loop (11). That is, an induced electromotive force (Vemf) is generated in a direction that offsets the change in the magnetic field by Lenz's law, and thereby an eddy current (Iemf) may flow counterclockwise as shown in Fig. 3a. In addition, an upward magnetic field may be generated by the eddy current Iemf as shown by the upward dotted arrow in Fig. 3a.

[0052] In an embodiment such as the above-described Fig. 3a, the relationship between the induced electromotive force (Vemf) and the eddy current (Iemf) can be expressed as Iemf = Vemf / (sL). That is, the impedance viewed from points A and B of the short loop (11) can be defined as the short circuit impedance (sL). That is, when the short circuit loop (11) has an inductance of L, the magnetic field (upward magnetic field) generated by the eddy current (Iemf) partially cancels out the magnetic field generated by the radioactive source (200), thereby obtaining a radiation noise reduction effect.

[0053] Meanwhile, in the embodiment of FIG. 3b, as in FIG. 3a, a source current (Isource) flows on a source loop (201) of a radiative source source (200), and radiative noise is generated that is radiated downward in the direction in which the source current (Isource) is traveling. In addition, it can be seen that a radiative noise reduction device (100) is provided above the radiative source source (200). As shown in FIG. 3b, the radiative noise reduction device (100) may include a circuit unit (102) and a compensation loop (101). According to one embodiment, as in the short-circuit loop (11) of FIG. 3a, the compensation loop (101) may be a wire loop having a loop inductance (L) based on points A and B. At this time, the loop inductance (L) may be a pre-measured or preset value.

[0054] In the embodiment of FIG. 3b, the compensation loop (101) is illustrated as having a shape almost identical to the loop area of ​​the source loop (201) located below, but the present invention is not limited thereto, and the compensation loop (101) may be provided in a shape capable of effectively canceling out radiation noise emitted by the radioactive source (200). According to one embodiment, the compensation loop (101) may be provided in a shape that surrounds or covers part or all of the radioactive source (200).

[0055] In more detail, the voltage between points A and B, which are connection points of the circuit unit (102) and the compensation loop (101) of the radiation noise reduction device (100), may be referred to as Vemf'. At this time, a current of Iemf' may flow in the compensation loop (101) due to the voltage Vemf' applied to both points. According to one embodiment of the present invention, the circuit unit (102) includes a negative impedance converter, and the propagation directions of Isource and Iemf' may be opposite to each other. In addition, according to one embodiment of the present invention, the radiation noise (upward arrow) generated by Iemf' and the radiation noise (downward arrow) generated by Isource may have opposite directions.

[0056] More specifically, as described in the description of Fig. 3a, the impedance of the short loop (11) can be referred to as (sL). According to one embodiment of the present invention, the radiation noise reduction device (100) is a circuit that uses the same short loop (11) as a compensation loop (101), disconnects points A and B of the compensation loop (101), and connects a circuit part (102). As described above, the circuit part (102) can include a negative impedance converter, and thus, the impedance of the circuit part (102) can be set to (-sL).

[0057] According to one embodiment of the present invention, since the impedance of the compensation loop (101) is (sL), when the impedance of the circuit unit (102) is (-sL), the overall impedance of the radiation noise reduction device (100) becomes 0. That is, the current (Iemf') flowing in the radiation noise reduction device and the voltage (Vemf') applied to points A and B can be expressed by the formula Iemf' = Vemf' / (sL - sL). Therefore, as the eddy current Iemf' is maximized, the canceling magnetic field is also maximized to cancel or reduce radiation noise. That is, the downward arrow (external magnetic field generated by the radiation source (200), i.e., radiation noise) shown in FIG. 3b can be canceled by the upward arrow (cancelling magnetic field generated by the radiation noise reduction device (100).

[0058] FIGS. 4A to 6B are drawings showing an active radiation noise reduction device according to another embodiment of the present invention.

[0059] Figures 4a to 6b are modified embodiments of the above-described Figure 2, and redundant descriptions will be omitted.

[0060] First, FIG. 4A is a drawing illustrating a compensation loop (101) and a circuit portion (102) of a radiation noise reduction device on a single circuit board (PCB), and a radiation source source (200) present in an inner circuit board region of the loop generated by the compensation loop (101). That is, according to one embodiment, a radiation source source (200) may be present on the circuit board, and the compensation loop (101) may be provided to surround the radiation source source (200). At this time, the distance between the compensation loop (101) and the source source (200) may be a minimum distance of 5 mm or more, but is not necessarily limited to this value.

[0061] FIG. 4b is a drawing illustrating a modified example of FIG. 4a, in which a compensation loop (101) of a radiation noise reduction device (100) exists on a single circuit board (PCB), but unlike FIG. 3a, the circuit portion (102) does not exist separately externally but exists within the radiation source source (200). That is, according to the embodiment of FIG. 4b, since a circuit capable of canceling out radiation noise exists within the radiation source source (200), the radiation noise reduction device can cancel out radiation noise passing through the compensation loop (101) on its own.

[0062] Meanwhile, according to another embodiment of the present invention, the compensation loop (101) and the radiative source source (200) may be located on the same plane or the same circuit board as in FIG. 2 or FIG. 3, but the present invention is not limited thereto, and the compensation loop (101) and the radiative source source (200) may be located on different planes.

[0063] FIGS. 5A to 6B illustrate examples in which a compensation loop (101) and a radioactive source (200) are positioned on different planes according to one embodiment of the present invention. FIGS. 5A to 6B are variations of FIGS. 4A and 4B, and therefore, a repeated description thereof will be omitted.

[0064] In more detail, FIG. 5a shows that a circuit board (PCB) and a radiative source source (200) exist on the xy plane, and a compensation loop (101) may exist on the yz plane perpendicular to the circuit board (PCB). At this time, the circuit unit (102) may exist on the same plane as the circuit board (PCB). In addition, FIG. 5b shows that, similar to FIG. 4b, a circuit connected to the compensation loop (101) exists within the radiative source source (200), and the radiative noise can be canceled out by itself using the compensation loop (101) located on the yz plane.

[0065] In addition, FIG. 6a shows that a circuit board (PCB) and a radiant source source (200) exist on the xy plane, and a compensation loop (101) may exist on the xz plane perpendicular to the circuit board (PCB). At this time, the circuit part (102) may exist on the same plane as the circuit board (PCB). In addition, FIG. 6b shows that, similar to FIG. 4b, a circuit connected to the compensation loop (101) exists within the radiant source source (200), and the radiant noise can be canceled out by itself by using the compensation loop (101) located on the xz plane.

[0066] According to the embodiments of FIGS. 5A to 6B, although the radiative source source (200) and the compensation loop (101) are on different planes, the radiative source source (200) exists in an inner region of the loop generated by the compensation loop (101), so that radiative noise emitted from the radiative source source (200) can be canceled out. In this regard, the embodiments of FIGS. 4A and 4B can effectively cancel out radiative noise emitted in the z-axis direction, the embodiments of FIGS. 5A and 5B can effectively cancel out radiative noise emitted in the x-axis direction, and the embodiments of FIGS. 6A and 6B can effectively cancel out radiative noise emitted in the y-axis direction.

[0067] Although the above-described embodiments have mentioned examples in which the compensation loop of the active radiation noise reduction device and the radiation source are on the same plane, parallel planes, or mutually perpendicular planes, according to another embodiment of the present invention, the angle formed by the compensation loop and the radiation source can be freely determined. That is, since the active radiation noise reduction device of the present invention can cancel out radiation noise passing through the inside of the compensation loop, the angle of the compensation loop that can effectively reduce radiation noise can be freely selected.

[0068] Figure 7 is a block diagram showing a radiation noise reduction device (100) according to one embodiment.

[0069] First, the compensation unit (110) corresponds to the compensation loop (101) of Fig. 3b and can play a role in canceling out radiation noise generated by the radiation source (200). In addition, the target unit (120) and the amplifier unit (130) correspond to the circuit unit (102) of Fig. 3b and can include a negative impedance converter and play a role in negatively converting the impedance (sL) of the compensation unit (110).

[0070] More specifically, the impedance (Zin) of the target unit (120) and the amplifier unit (130) as viewed from the compensation unit (110) may be a negative inverted value (-sL) of the impedance (sL) of the compensation unit (110). That is, the value of the impedance (Zt) of the target unit (120) amplified by the amplifier unit (130) may be a negative inverted value (-sL) of the impedance (sL) of the compensation unit (110). That is, the target unit (120) and the amplifier unit (130) may include a negative impedance converter circuit that senses the impedance (sL) of the compensation unit (110) and simultaneously compensates for the inversion. In the embodiments of FIGS. 5 to 8 below, specific embodiments of the radiation noise reduction devices (100) will be described.

[0071] Figures 8 and 9 illustrate a radiation noise reduction device according to the first embodiment of the present invention.

[0072] According to the first embodiment of the present invention, a radiation noise reduction device (100) can be implemented using two Op-amps. More specifically, referring to the embodiment of FIG. 8, a compensation unit (110) is illustrated as a block. Next, the compensation unit (110) is connected to an amplifier unit (130), and the amplifier unit (130) can be connected to a target unit (120). At this time, as shown in FIG. 8, both ends of the compensation unit (110) can be connected to the amplifier unit (130) through a resistor (Rf3), but in another embodiment of the present invention, the resistor (Rf3) connecting between the compensation unit (110) and the amplifier unit (130) can be omitted.

[0073] In more detail, the target unit (120) may include one or more inductors, although not specifically illustrated. In addition, the amplification unit (130) may include two op-amps each connected to both ends of the target unit (120), and a resistor (Rf1) connected to a positive input terminal of the op-amp and a resistor (Rf2) connected to a negative input terminal. That is, the negative input terminal of the op-amp and the resistor (Rf2) are connected in parallel to one end of the compensation unit (110). In addition, the positive input terminal of the op-amp and the resistor (Rf1) are connected in parallel with the target unit (120). In addition, the output terminal of the op-amp is connected in parallel with the resistor (Rf1) and the resistor (Rf2).

[0074] Figure 9 illustrates the circuit of Figure 8 in more detail.

[0075] Referring to Fig. 9, the circuit includes a compensation unit (110), a target unit (120), and an amplifier unit (130). The total impedance of the target unit (120), which includes a resistor (Rt) and an inductor (Lt), can be referred to as Zt.

[0076] In addition, the amplification unit (130) may include a first amplification unit (130a) and a second amplification unit (130b). The first amplification unit (130a) may include an Op-amp (Opa) and two resistors (Rf1, Rf2). More specifically, the positive input terminal of the Op-amp (Opa) is connected to the resistor (Rf1) and the target unit (120) described above. In addition, the negative input terminal of the Op-amp (Opa) is connected in parallel with point A of the compensation unit (110) and the resistor (Rf2). In addition, the output terminal (Vao) of the Op-amp (Opa) is connected in parallel with the resistor (Rf1) and the resistor (Rf2). That is, the output terminal (Vao) of the Op-amp (Opa) is fed back to the negative input terminal through the resistor (Rf2). Additionally, one end of the resistor (Rf1) is connected to the target section (120), and the other end is connected to the output terminal (Vao). One end of the resistor (Rf2) is connected in parallel to point A of the compensation section (110) and the negative input terminal, and the other end is connected to the output terminal (Vao).

[0077] Likewise, the second amplifier unit (130b) may include an Op-amp (Opb) and two resistors (Rf1, Rf2). More specifically, the positive input terminal of the Op-amp (Opb) is connected to the resistor (Rf1) and the target unit (120). In addition, the negative input terminal of the Op-amp (Opb) is connected to point B of the compensation unit (110) and the resistor (Rf2). In addition, the output terminal (vout) of the Op-amp (Opb) is connected to the resistor (Rf1) and the resistor (Rf2). In addition, one end of the resistor (Rf1) is connected to the target unit (120), and the other end is connected to the output terminal (Vbo). In addition, one end of the resistor (Rf2) is connected to point B of the compensation unit (110) and the output terminal (Vbo).

[0078] Below, we will examine in detail a method for calculating the input impedance (Zin) as viewed from the compensation unit (110), i.e., the impedance of the target unit (120) and the amplifier unit (130) by interpreting the circuit of FIG. 9.

[0079] First, due to the characteristics of Op-amp(Opa) and Op-amp(Opb), it can be assumed that the voltages of the positive and negative input terminals are the same. That is, the voltages of the positive and negative input terminals of Op-amp(Opa) are the same as Va. In addition, the voltages of the positive and negative input terminals of Op-amp(Opb) are the same as Vb. In addition, the gain (A0) of Op-amp(Opa) and Op-amp(Opa) is infinite, and the input impedance (Z in,opamp ) can also be said to be infinite. If this is expressed as a formula, it is as shown in [Mathematical Formula 1] below.

[0080]

[0081]

[0082] [Mathematical Formula 1]

[0083]

[0084] Next, when the current flowing in the A terminal of the compensation unit (110) is Iin, and the voltages of the Op-amp (Opa) and the output terminal of the Op-amp (Opa) are Vao and Vbo, respectively, the current Iin flowing in the compensation unit (110) and the current It flowing in the target unit (120) can be expressed as in [Mathematical Formula 2] below.

[0085]

[0086]

[0087] [Equation 2]

[0088]

[0089] In addition, the relationship between the input impedance (Zin) and the impedance (Zt) of the target section (120) as viewed from both ends (points A and B) of the compensation section (110) from the above [Mathematical Expression 2] can be expressed as in the following [Mathematical Expression 3].

[0090]

[0091]

[0092] [Equation 3]

[0093]

[0094] That is, the input impedance (Zin) is a negative inverted value obtained by multiplying the target impedance (Zt) by Rf2 / Rf1. Therefore, when the target unit (120) is provided with an inductor, the value of the loop inductor impedance (sL) generated by the source source (200) can be replicated as an inverted value. That is, according to one embodiment of the present invention, the value of the impedance (Zt) of the target unit (120) and the values ​​of the resistance (Rf1) and the resistance (Rf2) can be adjusted so that the input impedance (Zin) becomes Zin = -sL.

[0095] Figures 10 and 11 illustrate a radiation noise reduction device according to a second embodiment of the present invention.

[0096] A radiation noise reduction device (100) according to a second embodiment of the present invention can be implemented using one op-amp. Fig. 10 is a simplified representation of a circuit according to the second embodiment of the present invention. First, the target portion (120) may include one or more inductors (Lp) and may have a target impedance (Zt).

[0097] In more detail, the output terminal of the Op-amp can be connected to the target unit (120) and the feedback resistor (Rf). In addition, the positive input terminal of the Op-amp and the target unit (120) can be connected in parallel to point A of the compensation unit (110). In addition, the negative input terminal of the Op-amp and the feedback resistor (Rf) can be connected in parallel to one end of a ground resistor (Rg). In addition, the other end of the ground resistor (Rg) can be grounded and connected to point B of the compensation unit (110). In such a circuit, the target impedance (Zt), the feedback resistor (Rf), and the ground resistor (Rg) of the target unit (120) can be set so that the value of the input impedance (Zin) becomes a value obtained by negatively converting the impedance (sL) of the compensation unit (110).

[0098] In addition, Fig. 11 illustrates a circuit of a second embodiment of the present invention. Referring to Fig. 11, the target unit (120) and the amplifier unit (130) can be configured so that the input impedance (Zin) viewed from points A and B, which are opposite ends of the compensation unit (110), becomes a value obtained by negatively converting the impedance (sL) of the compensation unit (110).

[0099] In more detail, the target unit (120) may include a resistor (Rt), a capacitor (Ct), and an inductor (Lt). In another embodiment of the present invention, the resistor (Rt) or the capacitor (Ct) of the target unit (120) may be omitted. In addition, the amplification unit (130) may include one Op-amp having a gain of Ao. The output terminal of the Op-amp may be connected in parallel to the target unit (120) and the first on-resistor (Z1). In addition, the positive input terminal of the Op-amp may be connected in parallel to the compensation unit (110) and the target unit (120). In addition, the negative input terminal of the Op-amp may be connected in parallel to the first on-resistor (Z1) and the second on-resistor (Z2). Although in the embodiment of FIG. 11 the first on-resistance (Z1) and the second on-resistance (Z2) are illustrated as including only resistors, the first on-resistance (Z1) and the second on-resistance (Z2) may be a combination of one or more resistors, capacitors, and inductors.

[0100] Continuing, the voltage at the output of the Op-amp can be Vo, the voltage at the positive input can be vin+, the voltage at the negative input can be vin-, and the internal impedance of the Op-amp can be Zin,opamp. In addition, if the input current is Iin, and the current flowing through the first on-resistor (Z1) is Ire, Iin and Ire can be expressed as in [Mathematical Formula 4] below.

[0101]

[0102]

[0103] [Equation 4]

[0104]

[0105] Using the relationship of [Mathematical Formula 4] above, the process of calculating the input impedance (Zin) and the calculated input impedance (Zin) can be expressed as in [Mathematical Formula 5] below.

[0106]

[0107]

[0108] [Equation 5]

[0109]

[0110] That is, Zin is a negatively converted value of (Z2 / Z1)*Zt. Therefore, when the value of (Z2 / Z1)*Zt is set to be equal to the value of the impedance (sL) of the compensation unit (110), the radiation noise generated from the source (200) can be canceled out.

[0111] Figure 12 illustrates a radiation noise reduction device according to a third embodiment of the present invention.

[0112] Fig. 12 illustrates a noise reduction circuit using an amplifier (Amp). In this case, it is assumed that the gain of the amplifier (Amp) is Av, the input voltage is Vi, the output voltage is Vo, and the input current is Ii. In addition, in the circuit of Fig. 12, the feedback resistance (Zf) value of the amplifier (Amp) may be the target impedance (120, Zt=Zf) value of the target section (120). In this case, the input impedance (Zin), the input voltage (Vi), the input current (Ii), the output voltage (Vo), and the target impedance (Zf) may have a relationship as shown in [Mathematical Formula 6] below.

[0113]

[0114] Vi / (Ii-If)=Zin

[0115] If=(Vi-Vo) / Zf

[0116] Vo=Av*Vi

[0117] [Equation 6]

[0118]

[0119] Therefore, referring to [Mathematical Formula 6], Zin and Zf can have a relationship as shown in [Mathematical Formula 7] below, and the value of Zf can be adjusted so that Zin becomes a value that negatively inverts the impedance (sL) of the compensation unit (110).

[0120]

[0121] Ii / Vi + (1-Av) / Zf = 1 / Zin

[0122] [Equation 7]

[0123] In more detail, in order to make the value of Ii / Vi in [Mathematical Formula 7] very small, by setting the input impedance of the amplifier (Amp) high, it is possible to derive the input impedance (Zin) as in [Mathematical Formula 8] below.

[0124]

[0125]

[0126] [Equation 8]

[0127] Therefore, in the above [Mathematical Formula 8], when the gain of the amplifier (Amp) is set to 2 (Av=2) so that the input impedance (Zin) becomes a negatively inverted value of the impedance (sL) of the compensation unit (110), Zin=-Zf. That is, it is possible to simply invert the value of the target impedance (Zf). However, the present invention is not limited thereto, and a negative impedance of a required size can be designed through a design that adjusts the target impedance (Zf) and the gain (Av) value of the amplifier.

[0128] FIG. 13 is a drawing showing a specific circuit example of a radiation noise reduction device according to a third embodiment of the present invention.

[0129] Referring to FIG. 13, the circuit may include a compensation unit (110), a target unit (120, Zf), an amplifier unit (130), and an emitter follower (140, emitter follower).

[0130] As in the embodiment of FIG. 12 discussed above, there is an input impedance (Zin) viewed from the compensation unit (110), and the gain (Av) of the amplifier unit (130) can be adjusted so that the input impedance (Zin) becomes a value obtained by negatively inverting the impedance of the target unit (120). In addition, the emitter follower (140) can match the signal level of the circuit of FIG. 10 or transmit a voltage without voltage amplification. As described above, the radiation noise reduction device such as FIG. 13 can set the gain (Av) of the amplifier unit (130) to 2 by adjusting the values ​​of the elements (R1, R2, R3, R4, R5, R6Tr1, Tr2, C2) inside the amplifier unit (130), thereby making the input impedance (Zin) become a value obtained by negatively inverting the impedance of the target unit (120). In relation to this, it goes without saying that the internal element configuration of the amplifier (130) illustrated in Fig. 13 can be freely designed and modified so as to set a desired gain (Av) value.

[0131] The radiation noise reduction device of the present invention, as described above, can be applied to various devices to offset or reduce radiation noise generated during the operation of the devices. In a specific embodiment, the radiation noise reduction device of the present invention can be applied to a wireless power transmission system.

[0132] In this regard, wireless power transmission systems are a general term for devices and systems that transmit power using high-frequency electromagnetic fields. Their use is gradually expanding because they can transmit power without a direct wired connection. However, the radiated noise generated during wireless power transmission can cause interference with other electronic devices and reduce transmission efficiency. In particular, in addition to commercial wireless power devices, various issues related to radiated noise exist in household induction heaters (IH), induction heater-based direct water purifiers, automobiles, mobile phones, and industrial robot wireless power transmission systems. However, regulations regarding these issues exist only in the form of electromagnetic compatibility (EMC) testing.

[0133] To address this issue of radiated noise, existing methods have involved adjusting the wireless power transmission frequency to reduce radiated noise in specific frequency bands. However, adjusting the wireless power transmission frequency has the disadvantage of reducing power transmission efficiency.

[0134] Alternatively, a method of reducing radiation noise using physical shielding structures such as metal or magnetic absorbers has been used in the past.

[0135] Figure 14 is an example of using a shielding structure to reduce radiation noise.

[0136] Referring to FIG. 14, a wireless power transmission system (1410) including a transmitting end (Tx) at the bottom and a receiving end (Rx) at the top is illustrated. At this time, in order to reduce radiated noise generated in the wireless power transmission system (1410), a shielding structure (1421) may be installed at the top and bottom of the system, or a shielding structure (1422) may be installed between the transmitting end (Rx) and the receiving end (Tx). However, when a shielding structure (1421) is installed at the top and bottom, the frequency band for power transmission is also shielded, which causes a problem in that power transmission is blocked or efficiency is drastically reduced. Furthermore, when a shielding structure (1422) is installed in between, there is a problem in that power transmission becomes impossible at all according to the principle of wireless power transmission.

[0137] In contrast, a radiation noise reduction device according to an embodiment of the present invention can operate as an active electromagnetic interference (EMI) filter (AEF) that reduces or controls electromagnetic interference (EMI) caused by radiation noise (RE) without physical shielding or frequency change in a wireless power transmission system. In the following specification, for convenience of explanation, the circuit part of the radiation noise reduction device of the present invention is referred to as RE AEF, and the compensation part can be assumed as a coil connected to RE AEF.

[0138] FIG. 15 and FIG. 16 are drawings illustrating a radiation noise reduction device according to one embodiment of the present invention applied to a wireless power transmission system.

[0139] Referring to FIG. 15, when a wireless power transmission system (1510) including a lower transmitting end (Tx) and an upper receiving end (Rx) exists, a receiving end-side RE AEF (1521) and a coil (1522) may be provided at the upper end or around the receiving end (Rx), and a transmitting end-side RE AEF (1531) and a coil (1532) may be provided at the lower end or around the transmitting end (Tx). That is, the radiation noise reduction device according to the embodiment of FIG. 15 may be composed of a receiving end-side RE AEF (1521) and a coil (1522), and a transmitting end-side RE AEF (1531) and a coil (1532). At this time, when referring to the embodiments of FIGS. 2 to 6 described above, the RE AEFs (1521, 1531) may correspond to a circuit section, and the coils (1521, 1531) may correspond to a compensation loop (compensation section). That is, the coils (1521, 1531) may be provided to allow all or part of the radiated noise emitted from either the transmitter (Rx) or the receiver (Rx) of the wireless power transmission system to pass through.

[0140] The radiation noise reduction device according to the embodiment of Fig. 15 is an active electromagnetic wave reduction circuit, so it can pass the power transmission frequency and selectively reduce only the noise components in the electromagnetic wave interference band. That is, all or part of the radiation noise emitted from the receiving end (Rx) or the transmitting end (Tx) passes into the coil (1521, 1531), and this radiation noise can be reduced or canceled out by the radiation noise reduction device of the present invention.

[0141] According to an additional embodiment, although the embodiment of FIG. 15 illustrates that RE AEFs (1521, 1531) are provided on both the transmitting end side and the receiving end side, according to another embodiment of the present invention, RE AEFs may be provided only on one side, particularly on the side with severe radiation noise. In general, since radiation noise on the transmitting end side is more severe, according to one embodiment, the radiation noise reduction device may include only the RE AEF (1531) and coil (1532) on the transmitting end side.

[0142] FIG. 16 is a diagram illustrating an example of an actual implementation of a wireless power transfer system (1610), in which the wireless power transfer system (1610) is composed of a coil wound multiple times. The upper coil and the lower coil may respectively mean a transmitting end (Tx) coil and a receiving end (Rx) coil in wireless power transfer, or vice versa. In addition, RE AEFs (1621, 1631) and coils (1622, 1632) of a radiation noise reduction device according to an embodiment of the present invention may be provided near or on the same plane as the transmitting end (Tx) coil and the receiving end (Rx) coil of the wireless power transfer system (1610). The coils (1622, 1632) may be provided so that all or part of the radiation noise emitted from either the transmitting end (Rx) coil or the receiving end (Rx) coil passes therethrough. For example, if the upper coil is a receiving end (Rx) coil, the receiving end side RE AEF (1621) and coil (1622) may be provided on the same plane as the receiving end (Rx) coil. At this time, although coils (1622, 1632) are illustrated as once-wound coils in FIG. 16, they may be coils wound multiple times in other embodiments.

[0143] When using a radiation noise reduction device, i.e., RE AEF, according to an embodiment of the present invention together with a wireless power transmission system as illustrated in FIGS. 15 and 16 described above, a decrease in power transmission efficiency can be prevented compared to a passive shielding method. In addition, since RE AEF is an active AEF, it is possible to pass only the wireless power transmission frequency and selectively reduce only the noise component of the electromagnetic wave (EMI) band. For example, when the operating frequency of the wireless power transmission system is 75 kHz to 85 kHz, the corresponding frequency band can maintain transmission efficiency and selectively reduce only the electromagnetic noise frequency band.

[0144] Figures 17A and 17B are examples of a radiation noise reduction device according to one embodiment of the present invention applied to an actual product.

[0145] Fig. 17a illustrates an example in which a radiation noise reduction device according to an embodiment of the present invention is applied to a wireless charger for a mobile terminal. More specifically, Fig. 17a illustrates an example in which a transmitting end (Tx) side RE AEF (1711) is provided inside or outside the charger, and a receiving end (Rx) side RE AEF (1712) is provided near the battery of the mobile terminal. That is, by providing RE AEFs on the charger side and the battery side of the wireless charger for a portable terminal, radiation noise can be effectively reduced.

[0146] In addition, Fig. 17b illustrates an example in which a radiation noise reduction device according to an embodiment of the present invention is applied to a wireless charger for an electric vehicle. More specifically, an example is illustrated in which a wireless power transmitting end (Tx) side RE AEF (1720) is provided inside or near a wireless power transmitter installed on the floor. Although not illustrated in the embodiment of Fig. 17b, a wireless power receiving end (Rx) side RE AEF may also be provided inside or near a receiving end (Rx) side of a vehicle, i.e., inside or near a battery. In this way, radiation noise can be effectively reduced in a wireless charging system for an electric vehicle by using the radiation noise reduction device of the present invention.

[0147] While the present invention has been described with reference to one embodiment illustrated in the drawings, this is merely exemplary, and those skilled in the art will appreciate that various modifications and variations of the embodiments are possible. Therefore, the true scope of technical protection of the present invention should be determined by the technical spirit of the appended claims.

Claims

1. As a radiation noise reduction device for compensating for electromagnetic interference generated by a radiation source, A compensation unit including a compensation loop through which all or part of the radiant noise emitted from the source passes; A circuit section connected to the above compensation section and including one or more inductors and one or more amplifier sections; Including, A radiation noise reduction device in which the input impedance (Zin) of the above circuit section is a value obtained by converting the impedance of the above compensation section into a negative value.

2. In paragraph 1, A radiation noise reduction device, wherein the compensation loop is provided in a form that partially or completely surrounds the radiation source source so that at least a portion of the radiation noise emitted from the source source can pass through the plane or three-dimensional space inside the loop formed by the compensation loop.

3. In paragraph 1, A radiation noise reduction device, wherein the radiation noise reduction device is located on the same circuit board as the source source, and the compensation loop is provided in a form that surrounds the radiation source source.

4. In paragraph 1, A radiation noise reduction device, wherein the current flowing in the compensation section is a current that generates a canceling magnetic field having a direction opposite to that of the radiation noise passing through the compensation loop.

5. In paragraph 1, The above circuit part, A target portion comprising one or more inductors; An amplifier unit that connects the compensation unit and the target unit and includes one or more amplifiers; A radiation noise reduction device comprising:

6. In paragraph 5, A radiation noise reduction device in which the amplification unit includes two Op-amps, positive input terminals of the two Op-amps are respectively connected to both ends of the target unit, and negative input terminals are respectively connected to both ends of the compensation unit, and an input impedance (Zin) is calculated based on the resistances (Rf1, Rf2) connected to the input terminals of the Op-amps and the impedance (Zt) of the target unit.

7. In paragraph 6, A radiation noise reduction device in which the positive input terminals of the two op-amps are connected to the target section and the first resistor (Rf1), the negative input terminals are connected to the compensation section and the second resistor (Rf2), the output terminals are connected to the first resistor (Rf1) and the second resistor (Rf2), and the input impedance (Zin) is Zin=-(Rf2 / Rf1)*Zt.

8. In paragraph 5, A radiation noise reduction device, wherein the amplification section includes one Op-amp, a positive input terminal of the Op-amp is connected to one end of the target section and one end of the compensation section, a negative input terminal of the Op-amp is connected to a first on-resistance (Z1) and a second on-resistance (Z2), and an output terminal of the Op-amp is connected to the first on-resistance (Z1) and the other end of the target section, and the input impedance (Zin) is Zin=-(Z1 / Z2)*Zt.

9. In paragraph 1, The compensation unit of the above radiation noise reduction device is a radiation noise reduction device that is provided to allow all or part of the radiation noise emitted from either the transmitting end (Rx) coil or the receiving end (Rx) coil of the wireless power transmission system to pass through.

Images