KR20230136095A - Active current compensation device - Google Patents

Abstract

The present invention relates to a current compensation device that actively compensates for the first current input in common mode to each of at least two large current paths connected to the first device, and the second current supplied by the second device. At least two large current paths that transmit to the first device, a sensing unit that senses the first current on the large current path and generates an output signal corresponding to the first current, and amplifies the output signal of the sensing unit to amplify An amplification unit that generates a current, a compensation unit that generates a compensation current based on the amplification current and causes the compensation current to flow through each of the at least two high current paths, and an output impedance from the compensation unit to the second device. A current compensation device is provided, including a decoupling capacitor unit that satisfies predetermined conditions.

Description

Active current compensation device {ACTIVE CURRENT COMPENSATION DEVICE}

Embodiments of the present invention relate to an active current compensation device that actively compensates for a current input in common mode on two or more large current paths connecting two devices.

In general, electrical devices such as home appliances, industrial electrical products, or electric vehicles emit noise while operating. For example, noise may be emitted through power lines due to the switching operation of power conversion devices within electronic devices. If this noise is left unattended, it is not only harmful to the human body but also causes malfunctions or failures in surrounding parts and other electronic devices. In this way, the electromagnetic interference that electronic devices cause to other devices is called EMI (Electromagnetic Interference), and among them, noise transmitted through wires and board wiring is called conducted emission (CE) noise.

In order to ensure that electronic devices operate without causing malfunctions in surrounding components and other devices, the amount of EMI noise emissions from all electronic products is strictly regulated. Therefore, most electronic products necessarily include a noise reduction device (e.g., EMI filter) that reduces EMI noise current in order to satisfy regulations on noise emissions. For example, in white appliances such as air conditioners, electric vehicles, aviation, and energy storage systems (ESS), EMI filters are essential. Conventional EMI filters use a common mode choke (CM choke) to reduce common mode (CM) noise among conducted emission (CE) noise. A common mode (CM) choke is a passive filter that suppresses common mode noise current.

The present invention was made to improve the above problems, and its purpose is to provide an active current compensation device that outputs compensation current to the side where EMI noise is emitted, regardless of the size of the load on the side where EMI noise is emitted. do. However, these tasks are illustrative and do not limit the scope of the present invention.

According to an embodiment of the present invention, an active current compensation device that actively compensates for the first current input in common mode to each of at least two large current paths connected to the first device is provided by a second device. At least two high current paths for delivering the supplied second current to the first device; a sensing unit that senses the first current in the high current path and generates an output signal corresponding to the first current; an amplification unit that amplifies the output signal of the sensing unit to generate an amplification current; and a compensation unit that generates a compensation current based on the amplification current and flows the compensation current to each of the at least two high current paths. may include.

According to one embodiment, it may further include a decoupling capacitor unit provided to adjust the output impedance from the compensation unit to the second device.

According to one embodiment, the output impedance may be a composite impedance of the impedance of the second device and the impedance of the decoupling capacitor unit.

According to one embodiment, the compensation unit flows the compensation current to each of the at least two large current paths through a compensation capacitor unit, and the decoupling capacitor unit flows the compensation current to each of the at least two large current paths connecting the second device and the compensation capacitor unit. It may include at least two or more capacitors disposed on a path branching from.

According to one embodiment, the impedance of the at least two capacitors may be less than the critical impedance within a certain frequency band.

Other aspects, features and advantages in addition to those described above will become apparent from the following drawings, claims and detailed description of the invention.

According to various embodiments of the present invention as described above, it is possible to provide a current compensation device in which the price, area, volume, and weight do not significantly increase even in a high power system. Specifically, the active current compensation device according to various embodiments can be reduced in price, area, volume, and weight compared to a passive filter including a CM choke.

Additionally, the current compensation device according to various embodiments of the present invention can provide an active current compensation device that can operate independently without being parasitic on the CM choke.

Additionally, the active current compensation device according to various embodiments of the present invention has an active circuit stage that is electrically insulated from the power line, thereby stably protecting elements included in the active circuit stage.

Through this, the present invention can provide a current compensation device that can operate stably regardless of the characteristics of the surrounding electrical system, has versatility as an independent component, and can be commercialized as an independent module.

Through this, the present invention can provide a current compensation device that can perform a current compensation function regardless of the load of the surrounding situation on the side where EMI noise is emitted.

Of course, the scope of the present invention is not limited by this effect.

Figure 1 schematically shows the configuration of a system including an active current compensation device 100 according to an embodiment of the present invention.
FIG. 2 schematically shows a specific example of the active current compensation device 100A according to an embodiment shown in FIG. 1.
Figure 3 schematically shows the configuration of a system including an active current compensation device 100 according to another embodiment of the present invention.
FIG. 4 schematically shows a specific example of the active current compensation device 100A according to an embodiment shown in FIG. 3.
Figure 5 schematically shows an active current compensation device 100A-1 according to another embodiment of the present invention.
Figure 6 schematically shows an active current compensation device 100A-2 according to another embodiment of the present invention.
Figure 7 schematically shows an active current compensation device 100A-3 according to another embodiment of the present invention.
Figure 8 schematically shows the configuration of an active current compensation device (100C) according to another embodiment of the present invention.
Figure 9 schematically shows the configuration of an active current compensation device 100D according to another embodiment of the present invention.

Since the present invention can be modified in various ways and can have various embodiments, specific embodiments will be illustrated in the drawings and described in detail in the detailed description. The effects and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the drawings. However, the present invention is not limited to the embodiments disclosed below and may be implemented in various forms.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. When describing with reference to the drawings, identical or corresponding components will be assigned the same reference numerals and redundant description thereof will be omitted. .

In the following embodiments, terms such as first and second are used not in a limiting sense but for the purpose of distinguishing one component from another component. In the following examples, singular terms include plural terms unless the context clearly dictates otherwise. In the following embodiments, terms such as include or have mean that the features or components described in the specification exist, and do not exclude in advance the possibility of adding one or more other features or components. In the drawings, the sizes of components may be exaggerated or reduced for convenience of explanation. In cases where an embodiment can be implemented differently, a specific process sequence may be performed differently from the described sequence. In the following embodiments, when areas, components, parts, units, modules, etc. are connected, not only are the areas, components, parts, units, and modules directly connected, but also the areas, components, parts, units, and modules are connected. This also includes cases where other areas, components, parts, units, and modules are interposed and indirectly connected.

Figure 1 schematically shows the configuration of a system including an active current compensation device 100 according to an embodiment of the present invention. The active current compensation device 100 compensates for the first currents I11 and I12 (e.g., EMI) input in common mode (CM) from the first device 300 through two or more large current paths 111 and 112. noise current) can be actively compensated.

Referring to FIG. 1, the active current compensation device 100 may include a sensing unit 120, an amplifying unit 130, and a compensating unit 160.

In this specification, the first device 300 may be various types of devices that use power supplied by the second device 200. For example, the first device 300 may be a load driven using power supplied by the second device 200. Additionally, the first device 300 stores energy using power supplied by the second device 200, and may be a load (eg, an electric vehicle) driven using the stored energy. However, it is not limited to this.

In this specification, the second device 200 may be a device of various types for supplying power to the first device 300 in the form of current and/or voltage. For example, the second device 200 may be a device that produces and supplies power, or it may be a device that supplies power produced by another device (for example, an electric vehicle charging device). Of course, the second device 200 may be a device that supplies stored energy. However, it is not limited to this. A power conversion device may be located on the first device 300 side. For example, the first currents I11 and I12 may be input to the current compensation device 100 through a switching operation of the power conversion device. That is, the first device 300 side can correspond to the noise source, and the second device 200 side can correspond to the noise receiver.

The two or more large current paths 111 and 112 may be paths for transmitting the power supplied by the second device 200, that is, the second currents I21 and I22, to the first device 300, for example, they may be power lines. there is. For example, each of the two or more high current paths 111 and 112 may be a live line and a neutral line. At least a portion of the large current paths 111 and 112 may pass through the current compensation device 100. The second currents I21 and I22 may be alternating currents having a frequency in the second frequency band. The second frequency band may be, for example, a 50Hz to 60Hz band.

Additionally, the two or more large current paths 111 and 112 may be paths through which noise generated in the first device 300, that is, the first currents I11 and I12, is transmitted to the second device 200. The first currents I11 and I12 may be input in common mode to each of the two or more large current paths 111 and 112. The first currents I11 and I12 may be currents unintentionally generated in the first device 300 due to various causes. For example, the first currents I11 and I12 may be noise currents generated by virtual capacitance between the first device 300 and the surrounding environment. Alternatively, the first currents I11 and I12 may be noise currents generated by a switching operation of the power conversion device of the first device 300. The first currents I11 and I12 may be currents having a frequency in the first frequency band. The first frequency band may be a higher frequency band than the above-described second frequency band. The first frequency band may be, for example, a 150KHz to 30MHz band.

Meanwhile, the two or more large current paths 111 and 112 may include two paths as shown in FIG. 1, or may include three paths or four paths as shown in FIGS. 8 and 9. The number of high current paths 111 and 112 may vary depending on the type and/or type of power source used by the first device 300 and/or the second device 200.

The sensing unit 120 may detect the first currents I11 and I12 on the two or more large current paths 111 and 112 and generate output signals corresponding to the first currents I11 and I12. In other words, the sensing unit 120 may mean a means for detecting the first currents I11 and I12 on the large current paths 111 and 112. At least a portion of the large current paths 111 and 112 may pass through the sensing unit 120 for sensing the first currents I11 and I12, but an output signal is generated by sensing within the sensing unit 120. The portion may be insulated from the high current paths 111 and 112. For example, the sensing unit 120 may be implemented as a sensing transformer. The sensing transformer may sense the first currents I11 and I12 on the large current paths 111 and 112 while being insulated from the large current paths 111 and 112.

According to one embodiment, the sensing unit 120 may be differentially connected to the input terminal of the amplifying unit 130.

The amplification unit 130 is electrically connected to the sensing unit 120 and can amplify the output signal output by the sensing unit 120 to generate an amplified output signal. In the present invention, 'amplification' by the amplification unit 130 may mean adjusting the size and/or phase of the amplification target. The amplification unit 130 may be implemented by various means and may include active elements. In one embodiment, the amplification unit 130 may include OP-AMP. For example, the amplifier 130 may include a plurality of passive elements such as resistors and capacitors in addition to the OP-AMP. In another embodiment, the amplifier 130 may include a Bipolar Junction Transistor (BJT). For example, the amplifier 130 may include a plurality of passive elements such as resistors and capacitors in addition to the BJT. However, it is not limited to this, and the means for 'amplification' described in the present invention can be used without limitation as the amplification unit 130 of the present invention. The reference potential of the amplifier 130 (reference potential 2) and the reference potential of the current compensation device 100 (reference potential 1) may be different potentials.

The amplifier unit 130 receives power from the third device 400, which is distinct from the first device 300 and/or the second device 200, and amplifies the output signal output by the sensing unit 120. It can generate electric current. At this time, the third device 400 may be a device that receives power from a power source unrelated to the first device 300 and the second device 200 and generates input power to the amplifier 130. Optionally, the third device 400 may be a device that receives power from any one of the first device 300 and the second device 200 to generate input power for the amplifier 130.

The compensation unit 160 may generate a compensation current based on the output signal amplified by the amplifier 130. The output side of the compensation unit 160 may be connected to the high current paths 111 and 112 to flow compensation currents (IC1 and IC2) to the high current paths 111 and 112, but may be insulated from the amplification unit 130. For example, the compensation unit 160 may include a compensation transformer for the insulation. For example, the output signal of the amplifier 130 may flow through the primary side of the compensation transformer, and a compensation current based on the output signal may be generated on the secondary side of the compensation transformer.

The compensation unit 160 injects compensation currents (IC1, IC2) into the large current paths (111, 112) through each of two or more large current paths (111, 112) in order to offset the first currents (I11, I12). ) can be done. The compensation currents IC1 and IC2 may have the same magnitude and opposite phases as the first currents I11 and I12.

FIG. 2 shows a more specific example of the embodiment shown in FIG. 1 and schematically shows an active current compensation device 100A according to an embodiment of the present invention. The active current compensation device (100A) actively compensates for the first current (I11, I12) (e.g., noise current) input in common mode to each of the two large current paths (111A, 112A) connected to the first device (300A). Compensation is possible.

Referring to FIG. 2, the active current compensation device 100A may include a sensing transformer 120A, an amplifier 130A, and a compensation unit 160A.

In one embodiment, the above-described sensing unit 120 may include a sensing transformer 120A. At this time, the sensing transformer 120A may be a means for detecting the first currents I11 and I12 on the high current paths 111A and 112A while being insulated from the high current paths 111A and 112A. The sensing transformer 120A may sense the first currents I11 and I12, which are noise currents input from the first device 300A to the high current paths 111A and 112A (eg, power lines).

The sensing transformer 120A may include a primary side 121A disposed on the high current paths 111A and 112A, and a secondary side 122A differentially connected to the input terminal of the amplifier 130A. there is. The sensing transformer 120A is 2 based on the magnetic flux density induced by the first currents I11 and I12 in the primary side 121A (e.g., primary winding) disposed on the high current path 111A and 112A. An induced current can be created on the primary side (122A) (e.g., secondary winding). The primary side (121A) of the sensing transformer (120A) may be, for example, a winding in which a first high current path (111A) and a second high current path (112A) are each wound around one core. However, the present invention is not limited to this, and the primary side 121A of the sensing transformer 120A may have a first high current path 111A and a second high current path 112A passing through the core.

Specifically, the magnetic flux density induced by the first current (I11) on the first large current path (111A) (e.g., live line) and the first current (I12) on the second large current path (112A) (e.g., neutral line) The magnetic flux densities induced by may be configured to overlap (or reinforce) each other. At this time, second currents (I21, I22) also flow on the large current paths (111A, 112A), and the magnetic flux density induced by the second current (I21) on the first large current path (111A) and the second large current path (112A) ) The magnetic flux densities induced by the first current (I22) may be configured to cancel each other out. Also, as an example, the sensing transformer 120A may have the magnitude of the magnetic flux density induced by the first currents I11 and I12 in the first frequency band (for example, a band ranging from 150 KHz to 30 MHz) at the second frequency. It may be configured to be larger than the magnitude of the magnetic flux density induced by the second currents I21 and I22 in the band (for example, a band ranging from 50 Hz to 60 Hz).

In this way, the sensing transformer 120A is configured so that the magnetic flux densities induced by the second currents I21 and I22 cancel each other, so that only the first currents I11 and I12 are sensed. That is, the current induced in the secondary side 122A of the sensing transformer 120A may be a current obtained by converting the first currents I11 and I12 at a certain ratio.

For example, in the sensing transformer 120A, the turns ratio of the primary side 121A and the secondary side 122A is 1:N _sen , and the self-inductance of the primary side 121A of the sensing transformer 120A is L. When _sen , the secondary side 122A may have a self-inductance of N _sen ² L _sen . At this time, the current induced in the secondary side (122A) is 1/N _sen times the first current (I11, I12). For example, the primary side 121A and the secondary side 122A of the sensing transformer 120A may be combined with a coupling coefficient of k _sen .

The secondary side 122A of the sensing transformer 120A may be connected to the input terminal of the amplifier 130A. For example, the secondary side 122A of the sensing transformer 120A may be differentially connected to the input terminal of the amplifier 130A to supply an induced current to the amplifier 130A. Alternatively, depending on the configuration of the amplification unit 130A, the secondary side 122A of the sensing transformer 120A is a path connecting the input terminal of the amplification unit 130A and the reference potential (reference potential 2) of the amplification unit 130A. It may also be placed on a table. That is, one end of the secondary side (122A) may be connected to the input terminal of the amplification unit (130A), and the other end of the secondary side (122A) may be connected to the reference potential (reference potential 2) of the amplification unit (130A). .

The amplifying unit 130A may correspond to the amplifying unit 130 described above. The amplifier 130A may amplify the current detected by the sensing transformer 120A and induced in the secondary side 122A. For example, the amplification unit 130A may amplify the magnitude of the induced current at a certain rate and/or adjust the phase.

The compensation unit 160A may correspond to the compensation unit 160 described above. The compensation unit 160A may include a compensation transformer 140A and a compensation capacitor unit 150A. The amplified current amplified by the amplification unit 130A described above flows to the primary side 141A of the compensation transformer 140A.

The compensation transformer 140A may be a means for insulating the amplification unit 130A including an active element from the high current paths 111A and 112A. That is, the compensation transformer 140A is insulated from the high current paths 111A and 112A, and generates a compensation current (on the secondary side 142A) for injection into the high current paths 111A and 112A based on the amplified current. It may be a means for

The compensation transformer 140A may include a primary side 141A differentially connected to the output terminal of the amplifier 130A, and a secondary side 142A connected to the high current paths 111A and 112A. there is. Compensation transformer 140A induces a compensation current in secondary side 142A (e.g., secondary winding) based on the magnetic flux density induced by the amplification current flowing in primary side 141A (e.g., primary winding). can do.

At this time, the secondary side 142A may be placed on a path connecting the reference potential (reference potential 1) of the compensation capacitor unit 150A, which will be described later, and the current compensation device 100A. That is, one end of the secondary side (142A) is connected to the high current path (111A, 112A) through the compensation capacitor unit (150A), and the other end of the secondary side (142A) is the reference of the active current compensation device (100A). It can be connected to the potential (reference potential 1). Meanwhile, the primary side 141A of the compensation transformer 140A, the amplifier 130A, and the secondary side 122A of the sensing transformer 120A are separated from the remaining components of the active current compensation device 100A. It can be connected to the reference potential (reference potential 2). The reference potential (reference potential 1) of the current compensation device (100A) and the reference potential (reference potential 2) of the amplification unit (130A) can be distinguished.

As such, the present invention uses a different reference potential for the component that generates the compensation current from the remaining components and uses a separate power source, thereby allowing the component that generates the compensation current to operate in an insulated state. The reliability of the active current compensation device (100A) can be improved.

In the compensation transformer 140A, if the turns ratio of the primary side 141A and the secondary side 142A is 1:N _inj , and the self-inductance of the primary side 141A of the compensation transformer 140A is L _inj , The secondary side 142A may have a self-inductance of N _inj ² L _inj . At this time, the current induced in the secondary side (142A) is 1/N _inj times the current (i.e., amplification current) flowing in the primary side (141A). The primary side 141A and the secondary side 142A of the compensation transformer 140A may be coupled with a coupling coefficient of k _inj .

The current converted through the compensation transformer 140A may be injected as compensation currents IC1 and IC2 into the high current paths 111A and 112A (eg, power lines) through the compensation capacitor unit 150A. Accordingly, the compensation currents IC1 and IC2 may have the same magnitude and opposite phase as the first currents I11 and I12 in order to cancel the first currents I11 and I12. Accordingly, the size of the current gain of the amplification unit 130A can be designed to be N _sen N _inj .

As described above, the compensation capacitor unit 150A may provide a path through which the current generated by the compensation transformer 140A flows to each of the two large current paths 111A and 112A.

The compensation capacitor unit 150A includes two Y-capacitors (Y-capacitors), one end of which is connected to the secondary side (142A) of the compensation transformer (140A), and the other end of which is connected to the high current paths (111A, 112A). Y-cap) may be included. One end of each of the two Y-caps shares a node connected to the secondary side (142A) of the compensation transformer (140A), and the opposite ends of each of the two Y-caps are connected to the first high current path (111A) and the first high current path (111A), respectively. 2 It may have a node connected to the high current path (112A).

The compensation capacitor unit 150A may flow compensation currents IC1 and IC2 induced by the compensation transformer 140A to the power line. The current compensation device 100A can reduce noise by the compensation currents IC1 and IC2 compensating (or offsetting) the first currents I11 and I12.

Meanwhile, the compensation capacitor unit 150A may be configured so that the current IL1 flowing between the two large current paths 111A and 112A through the compensation capacitor is less than the first threshold size. Additionally, the compensation capacitor unit 150A may be configured so that the current IL2 flowing between each of the two large current paths 111A and 112A and the reference potential 1 through the compensation capacitor is less than the second threshold size.

The active current compensation device 100A can realize an isolated structure by using the compensation transformer 140A and the sensing transformer 120A.

Figure 3 schematically shows the configuration of a system including an active current compensation device 100 according to another embodiment of the present invention. Referring to FIG. 3, the current compensation device 100 shown in FIG. 1 may further include a decoupling capacitor unit 170. Detailed descriptions of components that overlap with the embodiment shown in FIG. 1 will be omitted.

The decoupling capacitor unit 170 may be a means for ensuring that the output impedance from the above-described compensation unit 160 to the second device 200 satisfies a predetermined condition. In other words, the decoupling capacitor unit 170 allows the compensation current to be output toward the second device 200 along at least two large current paths 111 and 112 and prevents it from returning to the active current compensation device 100. It could be a means.

For example, when the active current compensation device 100 satisfies the condition that the output impedance of the compensation unit 160 is less than the impedance of the compensation unit 160 itself, the first current generated by the first device 300 can increase the compensation effect. According to the embodiment, at least a portion of the compensation current flows toward the second device 200D so that at least a portion of the compensation current flows inside the current compensation device 100 along each of the two or more large current paths 111 and 112. The condition that it is greater than the amount flowing to the side can be satisfied.

The impedance of the second device 200 may vary arbitrarily depending on the surrounding conditions of the power system and filter. For example, home appliances may have various impedance values depending on their components (eg, motor, heater, light emitting device, etc.).

The decoupling capacitor unit 170 prevents the output performance of the compensation current of the active current compensation device 100 from significantly changing depending on changes in the impedance value of the second device 200, allowing it to be applied in various systems.

The active current compensation device 100 may be a feedforward type compensation filter that compensates for noise input from the first device 300 at the front end, which is the power source. That is, in the active current compensation device 100, the sensing unit 120 may be placed on the side of the first device 300, which is the noise source, and the compensation unit 160 may be placed on the second device 200, which is the power source. there is.

FIG. 4 schematically shows a specific example of the active current compensation device 100A according to an embodiment shown in FIG. 3. Referring to FIG. 4, the active current compensation device 100A shown in FIG. 2 may further include a decoupling capacitor unit 170B.

The decoupling capacitor unit 170B may be a means for ensuring that the output impedance from the above-described compensation unit 160A to the second device 200A satisfies a predetermined condition. In other words, the decoupling capacitor unit 170B allows the compensation current to be output to the second device 200A along at least two large current paths 111A and 112A, and prevents it from returning to the active current compensation device 100A. It could be a means.

The impedance (Z _n ) on the first device 300A side and/or the impedance (Z _line ) on the second device 200A side may vary arbitrarily depending on the surrounding conditions of the power system and filter. For example, home appliances may have various impedance values depending on their components (eg, motor, heater, light emitting device, etc.).

The decoupling capacitor unit 170B prevents the output performance of the compensation current of the active current compensation device 100A from significantly changing depending on changes in the impedance value of the second device 200A, allowing it to be applied in various systems.

This decoupling capacitor unit 170B includes at least two capacitors disposed on paths branching from each of at least two high current paths 111A and 112A connecting the second device 200A and the compensation capacitor unit 150A. It can be included.

Referring to FIG. 4, one end of each of the two capacitors included in the decoupling capacitor unit 170B may be connected to the reference potential (reference potential 1) of the active current compensation device 100A, and the opposite end of each of the two capacitors may be connected to the reference potential (reference potential 1) of the active current compensation device 100A. may be connected to the first high current path 111A and the second high current path 112A, respectively. The decoupling capacitor unit 170B may be connected to the power source side (i.e., the second device 200A side) of the active current compensation device 100A. Accordingly, the compensation accuracy of the second device 200A can be further improved. However, it is not limited to this.

The impedance (Z _Y ) of the decoupling capacitor unit 170B may be designed to have a sufficiently small value in the first frequency band that is the target of noise reduction. For example, the impedance Z _Y of the decoupling capacitor unit 170B may satisfy Equation 1.

Referring to Equation 1, the impedance viewed from the current compensation device (100A) to the second device (200A) can have a designed value of Z _Y regardless of any Z _line value due to the decoupling capacitor unit 170B. For example, the impedance Z _Y of the decoupling capacitor unit 170B may be designed to have a value smaller than a specified value within a specified frequency band (eg, a first frequency band). The impedance (Z _Y ) of the decoupling capacitor unit (170B) has a sufficiently small value in the first frequency band that is the target of noise reduction, so that the current compensation device (100A) has an impedance (Z _line ) on the second device (200A). ) can operate normally regardless.

Due to the combination of the decoupling capacitor portion 170B, the active current compensation device 100A can be used as an independent module in any system.

The active current compensation device 100A according to an embodiment of the present invention may not include a common mode (CM) choke. Since the CM choke functions as a passive filter, it must have a very large inductance to suppress leakage of the first currents (I11, I12) (e.g., noise current). Accordingly, the number of windings of the CM choke increases and the size of the core becomes very large. Unlike this CM choke, the sensing transformer 120A included in the current compensation device 100A according to an embodiment of the present invention is intended to sense the noise first currents I11 and I12, so it needs to have a large impedance. There is no The sensing transformer 120A may have an impedance of one thousandth to one hundredth of the impedance of the CM choke. Therefore, the size of the sensing transformer 120A can be much smaller than the size of the CM choke. The active current compensation device (100A) according to an embodiment of the present invention is not parasitic on the CM choke and can operate independently. Of course, in some cases, the active current compensation device (100A) can be operated in combination with a separate external CM choke that is independent of the active current compensation device (100A).

Figure 5 schematically shows an active current compensation device 100A-1 according to another embodiment of the present invention. The active current compensation device 100A-1 shown in FIG. 5 is an example of the current compensation device 100A shown in FIG. 4. In one embodiment, if the decoupling capacitor unit 170A is omitted from the active current compensation device 100A-1, the current compensation device 100A shown in FIG. 2 may be an example. The amplifier 130A-1 included in the active current compensation device 100A-1 is an example of the amplifier 130A of the active current compensation device 100A.

In the active current compensation device 100A-1, the amplification unit 130A of the active current compensation device 100A is implemented as an amplification unit 130A-1 having a non-inverting amplifier structure including an op-amp. In the amplifier unit 130A-1, power of Vcc and -Vcc may be supplied to the OP-amp from the third device 400A based on reference potential 2. R ₁ , R ₂ , R _f1 , C _f1 , R _f2 , and C _f2 included in the amplifier unit 130A-1 are elements for adjusting the gain of the non-inverting amplifier according to frequency. Specifically, in order to meet the limits of conducted emission (CE) within the first frequency band (e.g., 150 KHz to 30 MHz), the values of R ₁ , R ₂ , R _f1 , C _f1 , R _f2 , and C _f2 can be decided. For example, R ₁ , R ₂ , R _f1 , C _f1 , R f2 , and C _f2 so that the first currents (I11, I12) and the compensation currents (IC1, _IC2 ) are the same in size and opposite in phase. Values can be determined.

For example, in the sensing transformer 120A, if the turns ratio of the primary side 121A and the secondary side 122A is 1:N _sen , the current induced in the secondary side 122A is the first current I11 , I12) is 1/N _sen times. Additionally, in the compensation transformer 140A, if the turns ratio of the primary side 141A and the secondary side 142A is 1:N _inj , the current induced in the secondary side 142A is in the primary side 141A. It is 1/N _inj times the flowing current (i.e. amplification current).

Therefore, in order to cancel the first currents (I11, I12) and generate compensation currents (IC1, IC2) of the same magnitude and opposite phase as the first currents (I11, I12), the amplification unit (130A-1) The size of the current gain may need to satisfy N _sen N _inj . Accordingly, the values of R ₁ , R ₂ , R _f1 , C _f1 , R _f2 , and C _f2 can be satisfied such that the size of the current gain of the amplification unit 130A-1 is N _sen N _inj .

The amplification unit 130A-1 may include a high pass filter 401. The elements R ₀ and C ₀ included in the high-pass filter 401 may block the amplification unit 130A-1 from operating at low frequencies below the first frequency band that is the target of noise reduction.

According to one embodiment, a decoupling capacitor unit 170A may be disposed on the output side (i.e., the second device 200A side) of the active current compensation device 100A-1. That is, the decoupling capacitor unit 170A includes two capacitors disposed on paths branching from each of at least two high current paths 111A and 112A connecting the second device 200A and the compensation capacitor unit 150A. can do. One end of each of the two capacitors may be connected to the reference potential (reference potential 1) of the current compensation device 100A-1, and the opposite ends of each of the two Y-caps may be connected to the first high current path 111A and the second high current path 111A, respectively. It can be connected to the high current path (112A).

According to one embodiment, the decoupling capacitor unit 170A may be omitted in the active current compensation device 100A-1.

Figure 6 schematically shows an active current compensation device 100A-2 according to another embodiment of the present invention. The active current compensation device 100A-2 shown in FIG. 6 is an example of the active current compensation device 100A shown in FIG. 4. In one embodiment, if the decoupling capacitor unit 170A is omitted from the active current compensation device 100A-2, the active current compensation device 100A shown in FIG. 2 may be an example. The amplification unit 130A-2 included in the active current compensation device 100A-2 is an example of the amplification unit 130A of the active current compensation device 100A.

In the active current compensation device 100A-2, the amplification unit 130A of the active current compensation device 100A is implemented as an amplification unit 130A-2 having a push-pull amplifier structure including an npn BJT and a pnp BJT. It has been done.

The induced current induced in the secondary side (122A) by the sensing transformer (120A) may be differentially input to the amplifier (130A-2). At the input terminal of the amplifier unit 130A-2, a resistor R _in may be connected in parallel to the secondary side 122A. R _in can adjust the input impedance of the amplifier (130A-2). C _b and C _e can selectively combine only AC signals.

The third device 400A supplies a DC low voltage (V _DC ) based on reference potential 2 to drive the amplification unit 130A-2. C _DC is a decoupling capacitor for DC and can be connected in parallel to the third device (400A). C _DC can selectively couple only AC signals between both collectors of npn BJT and pnp BJT.

In the amplifier unit 130A-2, R _npn , R _pnp , R _bb , and R _e can adjust the operating point of the BJT. R _npn , R _pnp , R _bb , and R _e can be designed according to the operating point of the BJT. R _npn can connect the collector terminal of the npn BJT and the third device (400A) terminal and the base terminal of the npn BJT. R _bb can connect the base terminal of the npn BJT and the base terminal of the pnp BJT. R _pnp is the collector terminal of the pnp BJT and can connect the reference potential 2 and the base terminal of the pnp BJT.

Meanwhile, in the sensing transformer 120A, if the turns ratio of the primary side 121A and the secondary side 122A is 1:N _sen , the current induced in the secondary side 122A is the first current I11, I12 ) is 1/N _sen times, and in the compensation transformer (140A), if the turns ratio of the primary side (141A) and the secondary side (142A) is 1:N _inj , the current induced in the secondary side (142A) is, It is 1/N _inj times the current (i.e. amplification current) flowing in the primary side (141A). Therefore, in order to cancel the first currents (I11, I12) and generate compensation currents (IC1, IC2) of the same magnitude and opposite phase as the first currents (I11, I12), the amplification unit (130A-2) The current gain can be designed to be N _sen N _inj .

Meanwhile, the current flowing between the collector and emitter varies depending on the voltage applied between the base and emitter of the BJT. In the case of a positive swing where the input voltage of the amplifier 130A-2 due to noise is greater than 0, the npn BJT can operate. At this time, the operating current may flow through the first path 501. In the case of a negative swing where the input voltage of the amplifier 130A-2 due to noise is less than 0, the pnp BJT can operate. At this time, the operating current may flow through the second path 502.

Meanwhile, the transconductance (ratio of the output current to the input voltage of the BJT) of the BJT element is That is, the total transconductance of the amplifier (130A-2) can be expressed as Equation 2.

In Equation 2, I _out is the output current of the amplifier (130A-2) and is the current flowing in the primary side (141A) of the compensation transformer (140A). V _sen is the input voltage of the amplification unit 130A-2, and is the potential difference between both ends of the differential input terminal of the amplification unit 130A-2, that is, the voltage induced in the secondary side 122A of the sensing transformer 120A. As described above, represents the transconductance (ratio of output current to input voltage) that the BJT has without a feedback loop.

Therefore, the current gain of the amplification unit 130A-2 can be expressed as Equation 3.

In equation 3: represents the current gain of the amplification unit 130A-2. I _sen is the input current of the amplifier 130A-2, and is the current induced in the secondary side 122A by the sensing transformer 120A. I _out is the output current of the amplifier 130A-2 and is the current flowing in the primary side 141A of the compensation transformer 140A.

From this, the current gain of the amplification unit 130A-2 can be approximated as shown in Equation 4.

Meanwhile, as described above, the current gain of the amplification unit 130A-2 By designing this to be N _sen N _inj , the magnitude of the compensation currents (IC1, IC2) and the first currents (I11, I12) can be the same, and the compensation currents (IC1, IC2) can be used to create the first currents (I11, I12). can be offset.

In order to offset the first currents (I11, I12) with the compensation currents (IC1, IC2), the current gain of the amplification unit (130A-2) ( R _in /R _e ) can be designed to be N _sen N _inj .

According to one embodiment, a decoupling capacitor unit 170A may be disposed on the output side (i.e., the second device 200A side) of the active current compensation device 100A-2. That is, the decoupling capacitor unit 170A includes two capacitors disposed on paths branching from each of at least two high current paths 111A and 112A connecting the second device 200A and the compensation capacitor unit 150A. can do. One end of each of the two capacitors may be connected to the reference potential (reference potential 1) of the current compensation device 100A-2, and the opposite ends of each of the two Y-caps may be connected to the first high current path 111A and the second high current path 111A, respectively. It can be connected to the high current path (112A).

According to one embodiment, the decoupling capacitor unit 170A may be omitted in the active current compensation device 100A-2.

Figure 7 schematically shows an active current compensation device 100A-3 according to another embodiment of the present invention. The active current compensation device 100A-3 shown in FIG. 7 is an example of the active current compensation device 100A shown in FIG. 4. In one embodiment, if the decoupling capacitor unit 170A is omitted from the active current compensation device 100A-3, the active current compensation device 100A shown in FIG. 2 may be an example. The amplification unit 130A-3 included in the active current compensation device 100A-3 is an example of the amplification unit 130A of the active current compensation device 100A.

In the active current compensation device 100A-3, the amplification unit 130A of the active current compensation device 100A is implemented as an amplification unit 130A-3 having a push-pull amplifier structure including an npn BJT and a pnp BJT. It has been done.

The induced current induced in the secondary side (122A) by the sensing transformer (120A) may be differentially input to the amplifier (130A-3). The amplification unit 130A-3, unlike the amplification unit 130A-2 of FIG. 4, may not include a resistor R _in . C _b and C _e can selectively combine only AC signals.

The third device 400A supplies DC low voltage V _DC based on reference potential 2 to drive the amplification unit 130A-3. C _DC is a DC decoupling capacitor for the V _DC and may be connected in parallel to the third device 400A. C _DC can selectively couple only AC signals between both collectors of npn BJT and pnp BJT.

In the amplifier unit 130A-3, R _npn , R _pnp , R _bb , and R _e can adjust the operating point of the BJT. R _npn can connect the collector terminal of the npn BJT and the third device (400A) terminal and the base terminal of the npn BJT. R _bb can connect the base terminal of the npn BJT and the base terminal of the pnp BJT. R _pnp is the collector terminal of the pnp BJT and can connect the reference potential 2 and the base terminal of the pnp BJT.

Meanwhile, in one embodiment, the secondary side (122A) of the sensing transformer (120A) may be connected to the base and emitter terminals of the two BJTs, and the primary side (141A) of the compensation transformer (140A) may be connected to the collector of the two BJTs. and can be connected to the base. The amplification unit 130A-3 may have a regression structure that injects the output current back into the base of the BJT. Due to the regression structure, the amplification unit 130A-3 can stably obtain a constant current gain for operation of the active current compensation device 100A-3.

In the case of a positive swing where the input voltage of the amplifier 130A-3 due to noise is greater than 0, the npn BJT can operate. At this time, the operating current may flow through the first path 601. In the case of a negative swing where the input voltage of the amplifier 130A-3 due to noise is less than 0, the pnp BJT can operate. At this time, the operating current may flow through the second path 602.

Meanwhile, the current gain of the BJT device itself can be expressed as Equation 5.

In equation 5, represents the current gain of the BJT element itself, I _sen is the current flowing in the secondary side (122A) induced by the sensing transformer (120A), and I _out,BJT is the primary of the compensation transformer (140A). This is the current flowing in the side (141A). I _sen If expressed as a function of , it is as in Equation 6.

Therefore, the current gain of the amplification unit (130A-3) can be expressed as Equation 7.

Current gain of BJT Since has a value much larger than 1 (e.g., greater than 100), can be approximated as -1. Therefore, in the case of the active current compensation device 100A-3, by designing it to satisfy N _sen N _inj = 1, the first currents I11 and I12 can be offset with the compensation currents IC1 and IC2. That is, the turns ratio of the primary side (121A) to the secondary side (122A) of the sensing transformer (120A) and the turns ratio of the primary side (141A) to the secondary side (142A) of the compensation transformer (140A) satisfy the reciprocal. It can be designed to do so.

Unlike the amplification unit 130A-2 of the active current compensation device 100A-2 of FIG. 6, the amplification unit 130A-3 of the active current compensation device 100A-3 does not have R _in at the input terminal, and compensation output current ( ) may have a feedback structure that returns the signal back to the input terminal. Therefore, the amplification unit 130A-3 has limited current gain, but can obtain a more stable current gain than the amplification unit 130A-2.

According to one embodiment, a decoupling capacitor unit 170A may be disposed on the output side (i.e., the second device 200A side) of the active current compensation device 100A-3. That is, the decoupling capacitor unit 170A includes two capacitors disposed on paths branching from each of at least two high current paths 111A and 112A connecting the second device 200A and the compensation capacitor unit 150A. can do. One end of each of the two capacitors may be connected to the reference potential (reference potential 1) of the current compensation device 100A-3, and the opposite ends of each of the two Y-caps may be connected to the first high current path 111A and the second high current path 111A, respectively. It can be connected to the high current path (112A).

According to one embodiment, the decoupling capacitor unit 170A may be omitted in the active current compensation device 100A-3.

Figure 8 is a diagram schematically showing the configuration of an active current compensation device (100C) according to another embodiment of the present invention. Hereinafter, descriptions of content that overlaps with the content described with reference to FIGS. 1 to 7 will be omitted.

Referring to FIG. 8, the active current compensation device (100C) actively compensates the first current (I11, I12, I13) input in common mode to each of the high current paths (111C, 112C, and 113C) connected to the first device (300C). can be compensated with

For this purpose, the active current compensation device (100C) according to another embodiment of the present invention includes three large current paths (111C, 112C, 113C), a sensing transformer (120C), an amplifier (130C), a compensation transformer (140C), and a compensation transformer (140C). It may include a capacitor unit (150C).

In contrast to the active current compensation devices 100A and 100B according to the embodiment described in FIGS. 2 to 7, the active current compensation device 100C according to the embodiment shown in FIG. 8 has three large current paths 111C and 112C. , 113C), and accordingly, there is a difference between the sensing transformer (120C) and the compensation capacitor unit (150C). Therefore, hereinafter, the active current compensation device (100C) will be described focusing on the above-mentioned differences.

The active current compensation device 100C may include a first large current path 111C, a second large current path 112C, and a third large current path 113C that are distinct from each other. According to one embodiment, the first high-current path 111C may be an R-phase power line, the second high-current path 112C may be an S-phase power line, and the third high-current path 113C may be a T-phase power line. The first currents I11, I12, and I13 may be input to each of the first large current path 111C, the second large current path 112C, and the third large current path 113C in a common mode.

The primary side (121C) of the sensing transformer (120C) is disposed in each of the first large current path (111C), the second large current path (112C), and the third large current path (113C), and induces an induced current in the secondary side (122C). can be created. The magnetic flux densities generated in the sensing transformer 120C by the first currents I11, I12, and I13 on the three large current paths 111C, 112C, and 113C may reinforce each other.

Meanwhile, in the active current compensation device 100C, the amplification unit 130C may be implemented as one of the amplification units including the amplification unit 130A-1, the amplification unit 130A-2, and the amplification unit 130A-3. . However, it is not limited to this.

Meanwhile, the compensation capacitor unit 150C allows compensation currents (IC1, IC2, IC3) generated by the compensation transformer to flow into each of the first large current path (111C), the second large current path (112C), and the third large current path (113C). A route can be provided.

The active current compensation device 100C according to this embodiment can be used to compensate (or offset) the first currents I11, I12, and I13 moving from the load to the power source in a three-phase, three-wire power system.

The active current compensation device 100C may further include a decoupling capacitor portion 170C on the output side (i.e., the second device 200C side). The decoupling capacitor unit 170C may include three capacitors. One end of each of the three capacitors may be connected to the first high current path 111C, the second high current path 112C, and the third high current path 113C, respectively. Opposite ends of the three capacitors may be connected to the reference potential (reference potential 1) of the current compensation device 100C.

The impedance (Z _Y ) of the decoupling capacitor unit 170C may be designed to have a value smaller than a specified value in the first frequency band that is the target of noise reduction. Due to the combination of the decoupling capacitor portion 170C, the current compensation device 100C can be used as an independent module in any system (eg, 3-phase 3-wire system).

According to one embodiment, the decoupling capacitor unit 170C may be omitted in the active current compensation device 100C.

Figure 9 is a diagram schematically showing the configuration of an active current compensation device 100D according to another embodiment of the present invention. Hereinafter, descriptions of content that overlaps with the content described with reference to FIGS. 1 to 7 will be omitted.

Referring to Figure 9, the active current compensation device (100D) is a first current (I11, I12, I13, I13, I14) can be actively compensated.

To this end, the active current compensation device (100D) according to the embodiment includes four large current paths (111D, 112D, 113D, 114D), a sensing transformer (120D), an amplifier (130D), a compensation transformer (140D), and a compensation capacitor unit ( 150D) may be included.

In contrast to the active current compensation devices 100A and 100B according to the embodiment illustrated in FIGS. 2 to 7 and the active current compensation device 100C according to the embodiment illustrated in FIG. 8, according to the embodiment shown in FIG. 9 The active current compensation device (100D) includes four large current paths (111D, 112D, 113D, and 114D), and accordingly, there is a difference in the sensing transformer (120D) and the compensation capacitor portion (150D). Therefore, the following will describe the active current compensation device (100D) focusing on the above-mentioned differences.

The active current compensation device 100D may include a first large current path 111D, a second large current path 112D, a third large current path 113D, and a fourth large current path 114D. According to one embodiment, the first large current path (111D) is the R phase, the second large current path (112D) is the S phase, the third large current path (113D) is the T phase, and the fourth large current path (114D) is the It may be an N-phase power line. The first currents (I11, I12, I13, I14) include the first large current path (111D), the second large current path (112D), the third large current path (113D), and the fourth large current path (114D). ) can be input to each in common mode.

The primary side (121D) of the sensing transformer (120D) is disposed in each of the first large current path (111D), the second large current path (112D), the third large current path (113D), and the fourth large current path (114D), 2 An induced current can be generated on the car side (122D). The magnetic flux densities generated in the sensing transformer 120D by the first currents I11, I12, I13, and I14 on the four large current paths 111D, 112D, 113D, and 114D can be mutually reinforced.

Meanwhile, in the active current compensation device 100D, the amplification unit 130D may be implemented as one of the amplification units including the amplification unit 130A-1, the amplification unit 130A-2, and the amplification unit 130A-3. . However, it is not limited to this.

Meanwhile, the compensation capacitor unit 150D allows the compensation currents (ID1, ID2, ID3, ID4) generated by the compensation transformer to flow through the first large current path (111D), the second large current path (112D), the third large current path (113D), and A path flowing through each of the fourth large current paths 114D can be provided.

The active current compensation device 100D according to this embodiment can be used to compensate (or offset) the first current (I11, I12, I13, I14) moving from the load to the power source in a three-phase, four-wire power system. .

The active current compensation device 100D may further include a decoupling capacitor portion 170D on the output side (i.e., the second device 200D side). The decoupling capacitor unit 170D may include four capacitors. One end of each of the four capacitors may be connected to the first large current path 111D, the second large current path 112D, the third large current path 113D, and the fourth large current path 114D, respectively. Opposite ends of the four capacitors may be connected to the reference potential (reference potential 1) of the current compensation device 100D.

The impedance (Z _Y ) of the decoupling capacitor unit 170D may be designed to have a value smaller than a specified value in the first frequency band that is the target of noise reduction. Due to the combination of the decoupling capacitor portion 170D, the active current compensation device 100D can be used as an independent module in any system (eg, 3-phase 4-wire system).

According to one embodiment, the decoupling capacitor unit 170D may be omitted in the active current compensation device 100D.

Active current compensation devices according to various embodiments can operate stably regardless of the characteristics of the electrical system in which they are installed. Therefore, the active current compensation device does not need to be custom designed through repeated testing for each circuit or system, and can have versatility as an independent component. Active current compensation devices can be commercialized as independent modules.

Additionally, the active current compensation device according to various embodiments of the present invention can operate independently without being parasitic on the CM choke, and can reduce area, volume, and weight compared to a passive filter including a CM choke.

In addition, unlike the CM choke, the active current compensation device according to various embodiments shows only a slight increase in size or price even if it is used for high power. Specifically, the size, price, and weight of a passive filter including a CM choke rapidly increase if it is to be used in a high-power system due to the magnetic saturation phenomenon. However, the amplifier units (130A, 130A-1, 130A-2, 130A-3) included in the active current compensation device are not significantly affected by changes in power. In the active current compensation device, the volume increase rate of the sensing transformer (120A) according to the increase in power may be much smaller than the increase rate in volume (e.g., size and/or number) of the CM choke. Accordingly, active current compensation devices according to various embodiments may be much more advantageous in terms of price, volume, and weight than passive filters in high-power systems.

In addition, the active current compensation device according to various embodiments of the present invention has a structure that is electrically insulated from a high current path (e.g., a power line), so it can protect the elements included in the amplification unit 130A from electrical overstress (EOS). there is. For example, since the amplification unit 130A according to various embodiments of the present invention is insulated from the power line, it can use DC low voltage (e.g., third device 400, within 15V) used in the control board. Accordingly, the amplification unit 130A does not require a separate power conversion circuit. In addition, the active current compensation device according to various embodiments of the present invention is used to configure the amplification unit 130A, regardless of the reference potential (reference potential 1) of the power supply device (e.g., the second device 200). Elements with lower voltage ratings can be used.

The specific implementations described in the present invention are examples and do not limit the scope of the present invention in any way. For the sake of brevity of the specification, descriptions of conventional electronic components, control systems, software, and other functional aspects of the systems may be omitted. In addition, the connections or connection members of lines between components shown in the drawings exemplify functional connections and/or physical or circuit connections, and in actual devices, various functional connections or physical connections may be replaced or added. Can be represented as connections, or circuit connections. Additionally, if there is no specific mention such as “essential,” “important,” etc., it may not be a necessary component for the application of the present invention.

Therefore, the spirit of the present invention should not be limited to the above-described embodiments, and the scope of the patent claims described below as well as all scopes equivalent to or equivalently changed from the scope of the claims are within the scope of the spirit of the present invention. It will be said to belong to

Claims (1)

In the active current compensation device that actively compensates for the first current input in common mode to each of at least two large current paths connected to the first device,
at least two high current paths for transferring a second current supplied by a second device to the first device;
a sensing unit that senses the first current in the high current path and generates an output signal corresponding to the first current;
an amplification unit that amplifies the output signal of the sensing unit to generate an amplification current; and
a compensation unit that generates a compensation current based on the amplification current and causes the compensation current to flow through each of the at least two high current paths;
Active current compensation device including.