Magnetic integrated inductor assembly for LCL filter and LCL filter

Abstract

The embodiment of the utility model provides a magnetic integrated inductor assembly for an LCL filter and the LCL filter. The magnetic integrated inductor assembly comprises: a magnetic core having at least one magnetic circuit; the first winding and the second winding are wound at different magnetic circuit positions of the magnetic core respectively and are magnetically coupled and superposed through at least one magnetic circuit of the magnetic core, and the first winding and the second winding are arranged to enable the first winding to form machine-side inductance and enable the second winding to form resonant inductance. Therefore, the inductance value and the filtering performance can be improved, the ripple current and the magnetic core loss are reduced, and the copper wire consumption and the magnetic core size are reduced.

Description

TECHNICAL FIELD

[0001] Example embodiments of the present disclosure generally relate to the field of filters, and in particular, to a magnetic integrated inductor assembly for an LCL filter and an LCL filter. BACKGROUND

[0002] In electronic devices, LCL filters are widely used in inverters and power conversion systems, and play a crucial role in improving power quality and reducing harmonic pollution. LCL filters can filter current waveforms, making the current output by inverters or power converters smoother and reducing the interference of harmonics on the power grid.

[0003] However, the machine-side inductance, grid-side inductance, and resonance inductance of existing LCL filters are respectively arranged independently (hereinafter also referred to as discrete inductance) for filtering. Therefore, the existing LCL filter has problems of low core utilization rate, limited ripple current control capability, high loss, large space occupation, and high manufacturing cost. SUMMARY

[0004] The purpose of the present disclosure is to provide a magnetic integrated inductor assembly for an LCL filter and an LCL filter to at least partially solve the above-mentioned problems and / or other potential problems in conventional filters.

[0005] In a first aspect of the present disclosure, a magnetic integrated inductor assembly for an LCL filter and an LCL filter are provided. The magnetic integrated inductor assembly comprises: a magnetic core having at least one magnetic circuit; a first winding and a second winding connected in series, wound at different magnetic circuit positions of the magnetic core, respectively, and magnetically coupled and superimposed through the at least one magnetic circuit of the magnetic core, the first winding and the second winding are arranged such that the first winding forms a machine-side inductance, and the second winding forms a resonance inductance.

[0006] In embodiments according to the present disclosure, by the magnetic integrated inductor assembly, the machine-side inductance and the resonance inductance are integrated on the same magnetic core, which significantly improves the inductance and filtering performance, reduces the ripple current and core loss, reduces the amount of copper wire and the volume of the magnetic core, and improves the energy efficiency and reliability of the LCL filter. Other benefits will be described in conjunction with the corresponding embodiments below.

[0007] In some embodiments, the magnetic flux directions of the first winding and the second winding are consistent.

[0008] In some embodiments, the magnetic core comprises a ring structure, a mouth-shaped structure, or a CI type structure.

[0009] In some embodiments, the machine-side inductance and the resonance inductance are differential mode inductances, respectively.

[0010] In a second aspect of this disclosure, an LCL filter is provided. The LCL filter includes: a magnetically integrated inductor assembly according to the first aspect described above, wherein a first output terminal of a first winding of the magnetically integrated inductor assembly is electrically connected to a second input terminal of a second winding; a first capacitor, wherein a first terminal of the first capacitor is electrically connected to a second output terminal of the second winding of the magnetically integrated inductor assembly, and a second terminal of the first capacitor is grounded; a second capacitor, wherein a third terminal of the second capacitor is electrically connected to the first output terminal and the second input terminal, and a fourth terminal of the second capacitor is grounded; and a grid-side inductor, wherein a third input terminal of the grid-side inductor is electrically connected to the first output terminal, the second input terminal, and the third terminal of the second capacitor.

[0011] In some embodiments, the LCL filter further includes: a machine-side terminal electrically connected to a first input terminal, adapted to conduct an electrical connection with the inverter.

[0012] In some embodiments, the LCL filter further includes: a ground terminal connected to the second terminal of the first capacitor and the fourth terminal of the second capacitor.

[0013] In some embodiments, the LCL filter further includes: a load terminal electrically connected to a third output terminal of the grid-side inductor, adapted to conduct an electrical connection with the load.

[0014] In some embodiments, the first capacitor is a differential-mode capacitor.

[0015] In some embodiments, the second capacitor is a differential-mode capacitor.

[0016] It should be understood that the content described in this content section is not intended to limit the key or essential features of the embodiments of this disclosure, nor is it intended to restrict the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0017] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. In the drawings, the same or similar reference numerals denote the same or similar elements, wherein:

[0018] Figure 1 A schematic diagram of a magnetically integrated inductor assembly according to some embodiments of the present disclosure is shown;

[0019] Figure 2 A schematic diagram showing a first winding and a second winding connected to a magnetic core according to some embodiments of the present disclosure is shown; and

[0020] Figure 3 and Figure 4 A schematic diagram comparing the performance of a magnetically integrated inductor assembly and a discrete inductor solution according to some embodiments of the present disclosure is shown. Detailed Implementation

[0021] Embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings. While some embodiments of this disclosure are shown in the drawings, it should be understood that this disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this disclosure. It should be understood that the accompanying drawings and embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of protection of this disclosure.

[0022] In the description of embodiments of this disclosure, the term "comprising" and similar terms should be understood as open-ended inclusion, i.e., "including but not limited to". The term "based on" should be understood as "at least partially based on". The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The term "some embodiments" should be understood as "at least some embodiments". Other explicit and implicit definitions may also be included below. The terms "first", "second", etc., may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0023] As briefly mentioned earlier, existing LCL filters suffer from problems such as low core utilization, limited ripple current control capability, high losses, large footprint, and high manufacturing costs. Specifically, regarding the low core utilization, because the machine-side inductor, resonant inductor, and grid-side inductor of an LCL filter use independent cores, their magnetic circuits are independent, and the utilization rates of each core cannot complement each other, resulting in low efficiency in the use of magnetic materials. This not only increases the size and weight of the core but also raises production costs.

[0024] Regarding the limited ripple current control capability, in the discrete inductor arrangement, there is no coupling between the machine-side inductor and the resonant inductor, and their respective inductance values ​​must be arranged separately, making it difficult to effectively suppress ripple current. Furthermore, the independent arrangement of inductor values ​​leads to poor overall circuit filtering performance.

[0025] Furthermore, in the discrete inductor arrangement, the magnetic flux generated by each core exists independently, resulting in low magnetic energy utilization. Simultaneously, multiple cores generate higher magnetic and copper losses during operation, increasing the total loss of the LCL filter and thus reducing its efficiency. Additionally, the need for independent arrangement of multiple cores and windings leads to a larger space requirement for the inductor components, hindering miniaturization and integration of the LCL filter. Moreover, the discrete inductor arrangement is costly due to the need for multiple cores and windings.

[0026] To address, or at least partially address, the aforementioned problems or other potential problems of existing filters, embodiments of this disclosure provide a magnetically integrated inductor assembly for an LCL filter and an LCL filter scheme. The magnetically integrated inductor assembly includes a magnetic core, a first winding, and a second winding. The magnetic core has at least one magnetic circuit. Further, the first winding and the second winding are wound at different positions along the magnetic circuit of the magnetic core and are magnetically coupled and superimposed through at least one magnetic circuit of the magnetic core. The first winding and the second winding are arranged such that the first winding forms a machine-side inductor, and the first winding is connected in series with the second winding.

[0027] In this way, by winding the first and second windings at different positions on the magnetic core's magnetic circuit, magnetic coupling is achieved through the magnetic circuit of the core. This magnetically integrated inductor assembly significantly increases the effective inductance of the first winding (machine-side inductor) and the second winding (resonant inductor) without changing the number of winding turns. While keeping the first resonant point of the LCL filter constant, this magnetically integrated inductor assembly improves the filtering performance in the high-frequency range, enabling more efficient filtering of high-frequency harmonics in the inverter output, thereby improving power quality.

[0028] Secondly, by increasing the inductance, the ripple current in the first winding (machine-side inductor) and the second winding (resonant inductor) is reduced, thus lowering core losses and reducing electromagnetic interference and thermal load on power devices in the circuit. This significantly improves the overall energy efficiency of the LCL filter and the operational reliability of the entire system. Furthermore, while maintaining the filtering performance of the LCL filter, the amount of copper wire used in the first and second windings can be effectively reduced.

[0029] Meanwhile, this integrated magnetic inductor assembly can also reduce the amount of magnetic core used. Compared with existing discrete inductor solutions, this integrated magnetic inductor assembly significantly reduces the size of the magnetic core while ensuring inductance and filtering performance, improving the overall structure of the inductor assembly and ensuring the miniaturization of electronic devices such as filters.

[0030] An example structure and operation of a magnetically integrated inductor assembly 110 used in an LCL filter 100 in an electronic device will be described below. The LCL filter 100 according to an embodiment of this disclosure includes a magnetically integrated inductor assembly 110, a first capacitor 120, a second capacitor 130, and a grid-side inductor 140. This LCL filter 100 aims to improve filtering performance, reduce harmonic interference, and lower the overall loss and cost of the LCL filter 100 through the magnetically integrated inductor assembly 110.

[0031] Specifically, the first output terminal of the first winding 1111 of the magnetically integrated inductor assembly 110 is electrically connected to the second input terminal of the second winding 1121. In this way, the first winding 1111 and the second winding 1121 work together on the same magnetic core 1101 through magnetic coupling, generating a mutual inductance effect. The first winding 1111 is arranged to form a machine-side inductance 111 to limit variations in the inverter output current and effectively reduce ripple current. Further, the second winding 1121 is arranged to form a resonant inductance 112 to filter high-frequency harmonics. This magnetically integrated inductor assembly will be described in detail below.

[0032] Furthermore, the first capacitor 120 is used to form a resonant circuit with the second winding 1121 of the magnetic integrated inductor assembly 110. Specifically, the first terminal of the first capacitor 120 is electrically connected to the second output terminal of the second winding 1121 of the magnetic integrated inductor assembly 110, and the second terminal of the first capacitor 120 is grounded. Through this connection, the first capacitor 120 and the second winding 1121 together form a resonant circuit. This resonant circuit can effectively filter out high-frequency harmonics in a specific frequency band, improve the filtering performance of the LCL filter 100 in the high-frequency band, thereby improving power quality and reducing harmonic interference to the power grid.

[0033] Furthermore, the second capacitor 130 is used to enhance the filtering effect. The third terminal of the second capacitor 130 is electrically connected to the first output terminal and the second input terminal. The fourth terminal of the second capacitor 130 is grounded to form a closed-loop filtering circuit and stabilize the power transmission between the grid and the inverter.

[0034] Furthermore, the third input terminal of the grid-side inductor 140 is electrically connected to the first output terminal, the second input terminal, and the third terminal of the second capacitor 130. Through this connection, the grid-side inductor 140, together with the magnetic integrated inductor assembly 110, the first capacitor 120, and the second capacitor 130, form a high-efficiency filter network, effectively reducing harmonic currents transmitted through the power grid and protecting power grid equipment from harmonic interference.

[0035] In this way, the LCL filter 100, through the coordinated operation of the magnetic integrated inductor component 110, capacitors, and grid-side inductor 140, improves the overall performance of the LCL filter 100 while ensuring efficient filtering. The first capacitor 120 and the second capacitor 130 form resonant circuits with the magnetic integrated inductor component 110, thereby enhancing filtering performance, especially in high-frequency harmonic suppression. The grid-side inductor 140 further ensures the stable operation of the power grid and avoids harmonic interference.

[0036] As can be understood, the grid side refers to the side closest to the power grid or the load receiving end. Further, the grid-side inductor 140, also known as the outer inductor, is located on the side of the LCL filter 100 closest to the power grid. The grid-side inductor 140 is used to further filter high-frequency components in the current before power is transmitted to the power grid.

[0037] In some embodiments, the LCL filter 100 further includes a machine-side terminal. This machine-side terminal is electrically connected to the first input terminal and is adapted to establish an electrical connection with the power supply or inverter. The machine-side terminal is intended to connect the LCL filter 100 to the power supply or inverter, thereby enabling current filtering and control, ensuring that the output signal of the inverter or power supply can be stably transmitted to the load or the power grid after filtering.

[0038] In practical applications, the connection terminal on the machine side is the power supply output terminal or the inverter output terminal. This port is electrically connected to the first input terminal of the LCL filter 100. Through this connection, the LCL filter 100 can act as an intermediary between the power supply or inverter and the power grid, filtering out harmonics and high-frequency noise in the inverter or power supply output, thereby improving the power quality of the power grid.

[0039] Understandably, the machine side refers to the side closest to the output of the power electronic converter (such as an inverter). Further, the machine-side inductor 111, also known as the source-side inductor or internal inductor, is located on the side of the LCL filter 100 closest to the power converter (e.g., the inverter). The machine-side inductor 111 is used to suppress current ripple on the converter side, making the current injected into the LCL filter 100 smoother.

[0040] In some embodiments, the LCL filter 100 further includes a ground terminal. This ground terminal is electrically connected to a second terminal of the first capacitor 120 and a fourth terminal of the second capacitor 130. The ground terminal ensures stable operation of the LCL filter 100 circuitry and provides a common ground reference point for the LCL filter 100, thereby effectively suppressing noise and current ripple.

[0041] In practical applications, the grounding terminal connects the second terminal of the first capacitor 120 and the fourth terminal of the second capacitor 130 to the ground via an electrical connection. This ensures stable operation of the capacitors during filtering and guarantees the electrical safety of the filter. The first capacitor 120 and the second capacitor 130 are used as components for power filtering, and their connection to the grounding terminal forms a stable electrical circuit to reduce high-frequency noise and current ripple in the LCL filter 100.

[0042] Furthermore, grounding the second terminal of the first capacitor 120 helps to provide a low-impedance path, enabling the capacitor to effectively absorb and filter high-frequency noise and harmonics in the inverter or power supply output; while grounding the fourth terminal of the second capacitor 130 helps to stabilize the voltage waveform at the grid or load end.

[0043] In some embodiments, the LCL filter 100 further includes a load terminal. This load terminal is electrically connected to the third output terminal of the grid-side inductor 140 and is adapted to establish an electrical connection with the load. The load terminal is designed to stably transmit filtered electrical energy to the load, thereby ensuring that the load device receives a high-quality power signal and effectively suppressing any harmonic components transmitted by the power supply or inverter.

[0044] The load terminal is electrically connected to the third output terminal of the grid-side inductor 140, which is used to transmit the filtered signal from the filter to the load device. For example, the load terminal can be electrically connected to devices such as motors, inverter loads, and grid access ports.

[0045] Through this electrical connection, the LCL filter 100 can effectively filter out high-frequency harmonics in the power supply or inverter output, reduce ripple current, and ensure the smoothness of the current waveform.

[0046] In some embodiments, in this LCL filter 100, both the first capacitor 120 and the second capacitor 130 are differential-mode capacitors. Differential-mode capacitors are used to effectively suppress differential-mode noise in the power supply or inverter output signal and improve filtering performance, ensuring power quality in the power transmission system.

[0047] Furthermore, differential-mode capacitors are capacitors used to suppress differential-mode noise. They can effectively filter and reduce current interference and voltage fluctuations between different phases in a circuit, especially in power electronic equipment where their filtering effect on current ripple and harmonics is particularly outstanding. Differential-mode noise is caused by factors such as current imbalance, ground noise, and electromagnetic interference. Differential-mode capacitors, through their capacitive response to high-frequency signals, can effectively reduce this differential-mode interference.

[0048] Furthermore, the first capacitor 120 can be a differential-mode capacitor, with one end connected to the second output terminal of the second winding 1121 of the magnetic integrated inductor assembly 110, and the other end grounded. The first differential-mode capacitor is used to absorb and filter high-frequency differential-mode noise output from the power supply or inverter, preventing it from affecting subsequent power transmission. The second capacitor 130 can also be a differential-mode capacitor, with one end connected between the first winding 1111 and the second winding 1121 of the inductor assembly, and the other end grounded. Through its synergistic effect with the first capacitor 120, the second differential-mode capacitor filters differential-mode noise at lower frequency bands, particularly improving the filtering effect in the mid-frequency and low-frequency bands.

[0049] The following will combineFigure 1 and Figure 2 The specific structure of the magnetic integrated inductor assembly 110 is described below. In the embodiments of this disclosure, the magnetic integrated inductor assembly 110 generally includes a magnetic core 1101, a first winding 1111, and a second winding 1121. The magnetic integrated inductor assembly 110 aims to improve inductance performance, reduce the loss of the magnetic core 1101, reduce the amount of copper wire used, and improve the overall efficiency and reliability of the filter.

[0050] Specifically, the magnetic core 1101 has at least one magnetic circuit. The magnetic core 1101 can be made of iron powder core or a high-permeability material to provide a suitable magnetic flux path. The magnetic core 1101 can provide multiple magnetic circuits as needed to accommodate different inductance and current requirements.

[0051] Furthermore, the first winding 1111 is connected in series with the second winding 1121. The first winding 1111 and the second winding 1121 are wound at different magnetic circuit positions of the magnetic core 1101, and are magnetically coupled and superimposed through at least one magnetic circuit of the magnetic core 1101. The first winding 1111 is arranged to form a machine-side inductor 111, which is used to limit the variation of the inverter output current and suppress high-frequency ripple current. The second winding 1121 is arranged to form a resonant inductor 112, which is used to form a resonant circuit with the first capacitor 120 to filter out harmonics in a specific frequency band.

[0052] Furthermore, the first output terminal of the first winding 1111 is electrically connected to the second input terminal of the second winding 1121 via a wire. In this way, the first winding 1111 and the second winding 1121 form a closed loop through magnetic coupling, thereby increasing their respective inductances through mutual inductance. This increase in mutual inductance effectively reduces the ripple current of the machine-side inductor 111 and reduces the core loss 1101, improving the overall performance of the LCL filter.

[0053] The magnetic circuits and number of windings of the first winding 1111 and the second winding 1121 can be arranged according to actual needs to ensure that their mutual inductance is within an appropriate range. The magnitude of the mutual inductance can be achieved by adjusting the number of turns of the two windings, the winding layout, and the selection of the material of the magnetic core 1101. In this way, the magnetically integrated inductor can effectively increase the inductance value, improve the performance of the filter, and ensure the same ripple current suppression capability as existing discrete inductor solutions while reducing the amount of copper wire used.

[0054] In practical applications, the geometry, material, and magnetic circuit configuration of the magnetic core 1101 can be adjusted according to different application scenarios to meet the filtering requirements of the LCL filter 100 in different frequency bands. By adjusting the arrangement of the magnetic core 1101, the first winding 1111, and the second winding 1121, the size and cost of the inductor components can be further reduced, the reliability of the filter can be improved, and the losses of the magnetic core 1101 and the copper wire can be reduced.

[0055] Understandably, this magnetically integrated inductor component 110 is widely applicable to LCL filters 100 in power electronic devices, especially in systems requiring high-efficiency filtering and high reliability, such as inverters and active filters. Through this magnetically integrated inductor component 110, not only can the filtering performance of the LCL filter 100 be effectively improved, but the system cost and energy loss can also be reduced.

[0056] In some embodiments, in the magnetic integrated inductor assembly 110, the magnetic flux directions of the first winding 1111 and the second winding 1121 are consistent, which means that the magnetic flux generated by the two windings in the magnetic core 1101 is distributed in the same direction, thereby ensuring the magnetic coupling superposition between them.

[0057] In practice, the first winding 1111 and the second winding 1121 are magnetically coupled through multiple magnetic circuits of the same magnetic core 1101. The winding directions of the first winding 1111 and the second winding 1121 should be the same. Specifically, when the first winding 1111 is wound, the winding direction of the coil is the same as that of the second winding 1121, thus ensuring that the magnetic flux generated by the two windings is in the same direction when they are working.

[0058] When the magnetic flux directions of the first winding 1111 and the second winding 1121 are aligned, the mutual inductance between the two windings increases, thereby improving the performance of the magnetically integrated inductor assembly 110. The increased mutual inductance helps reduce the ripple current of the machine-side inductor 111 and further reduces the core 1101 loss. Furthermore, the increased inductance also helps improve the high-frequency filtering effect of the LCL filter 100, enabling the filter to more effectively suppress high-frequency harmonic components in the current.

[0059] Furthermore, since the two windings share the same magnetic flux path of the same magnetic core 1101, the utilization efficiency of the magnetic core 1101 is greatly improved, enabling the magnetic core 1101 of the same volume to provide higher inductance, thereby reducing the overall size and weight of the magnetic integrated inductor assembly 110.

[0060] In some embodiments, the magnetic core 1101 may adopt a ring structure, a square structure, or a CI structure to meet the requirements of different application scenarios for magnetic integrated inductors.

[0061] Furthermore, the toroidal magnetic core is shaped similarly to a complete circular ring. Two windings are wound around the outer or inner surface of the core, respectively. Because the toroidal core has a closed magnetic flux path, its magnetic field circulates within the core, reducing flux leakage and increasing flux density, thereby improving inductance. The toroidal magnetic core is suitable for applications requiring high inductance and low loss, and is applicable to the magnetically integrated inductor assembly 110 to achieve efficient magnetic coupling. By rationally configuring the winding method of the first winding 1111 and the second winding 1121, the magnetic flux directions of the two windings can be aligned, improving mutual inductance and further enhancing the performance of the inductor assembly.

[0062] Furthermore, the U-shaped magnetic core consists of a central U-shaped iron core and four opposing magnetic circuits. This structure allows for efficient multi-winding layouts, facilitating magnetic coupling of multiple windings on a single core 1101. The U-shaped core provides more flexible winding space due to its open portion, suitable for arranging the first winding 1111 and the second winding 1121 in different magnetic circuit positions, while ensuring consistent magnetic flux direction between the two windings, thus guaranteeing mutual inductance and inductance performance.

[0063] Furthermore, the CI-type magnetic core has the shape of the letter "CI" and consists of two magnetic circuit sections. The middle magnetic circuit section can provide a larger winding space, while the magnetic circuit sections at both ends can effectively guide the magnetic flux into the winding. The CI-type magnetic core can provide a high inductance value within a limited space and achieve low core loss. In the magnetically integrated inductor assembly 110, the CI-type magnetic core can effectively concentrate the magnetic flux of the first winding 1111 and the second winding 1121 within the core, and through reasonable wiring and magnetic flux guidance, ensure the overall performance of the inductor device.

[0064] Regardless of whether a toroidal, rectangular, or CI-type magnetic core is chosen, the goal is to ensure that the magnetic flux directions of the first winding 1111 and the second winding 1121 are aligned, thereby improving the inductance and filtering effect while reducing core losses and inductor size.

[0065] In practical applications, appropriate core structures can be selected based on different needs. For example, toroidal cores are suitable for scenarios requiring high inductance and stable filtering performance, U-shaped cores are suitable for larger currents and multiple windings, while CI-type cores can provide high inductance performance in space-constrained situations. By rationally selecting the core structure, the magnetically integrated inductor component 110 of the LCL filter 100 can be ensured to have efficient filtering capability, low loss, high reliability, and meet the needs of different application scenarios.

[0066] In some embodiments, in the LCL filter 100, both the machine-side inductor 111 and the resonant inductor 112 are differential-mode inductors. Differential-mode inductors can significantly improve the filtering performance of the filter and effectively suppress differential-mode noise and high-frequency ripple generated by the inverter or power supply. By using differential-mode inductors, the harmonic suppression capability of the LCL filter 100 can be improved, ensuring the smoothness of the current waveform and the stability of the power quality during filter operation.

[0067] Furthermore, the machine-side inductor 111 is used to limit variations in the inverter or power supply output current and suppress current ripple. This machine-side inductor 111 can be a differential-mode inductor, meaning its inductor coil is coupled through a magnetic core 1101 to filter the differential-mode component of the current. When operating, the differential-mode inductor effectively suppresses high-frequency noise and current ripple generated by the power supply or inverter, reducing the impact of these undesirable current components on the system and improving the stability and reliability of the power system.

[0068] Furthermore, the resonant inductor 112 can also be a differential-mode inductor, forming a resonant circuit together with the first capacitor 120 to improve the frequency response of the filter and effectively suppress harmonics in the high-frequency band. The differential-mode resonant inductor 112 can effectively enhance the filtering effect of the filter through magnetic coupling superposition, especially in terms of the differential-mode component of the current. By adjusting its self-inductance and magnetic coupling characteristics, the differential-mode inductor plays a role in filtering noise and stabilizing the current waveform in the power system. The selection and configuration of the differential-mode inductor can ensure that the magnetic flux generated by both is in the same direction during operation, thereby improving the overall performance of the magnetically integrated inductor assembly, reducing the ripple current in the machine-side inductor 111, and reducing the loss of the inductor core 1101.

[0069] In this way, by magnetically integrating the machine-side inductor 111 and the resonant inductor 112, the mutual inductance between the coils is used to increase their respective inductance, thereby effectively reducing the ripple current of the machine-side inductor 111, the loss of the magnetic core 1101, and the cost of the inductor, and improving the reliability of the product.

[0070] The specific principle of the magnetically integrated inductor assembly 110 will be described below by way of example. Figures 1 to 4 As shown, the resonant inductor Lx and the machine-side inductor L1 in the LxCx branch of the LCL filter are integrated onto the same magnetic core. Compared to the traditional discrete inductor solution 150, this magnetically integrated inductor increases the effective inductance of L1 and Lx by utilizing the mutual inductance principle, thereby reducing the ripple current on the inductor and the core loss. Secondly, without changing the first resonant point of the LCL filter, the filtering effect in the high-frequency band is improved. In addition, while ensuring that the LCL filter has the same ripple current suppression capability as the existing discrete inductor solution 150, the amount of copper wire used in L1 and Lx can be reduced, thereby further reducing the manufacturing cost of the inductor.

[0071] Specifically, the magnetic integrated inductor is achieved by adding an Lx coil to the magnetic core of inductor L1, with Lx and L1 connected in parallel. Figure 1 The electrical connection is shown. The currents in the two inductors generate magnetic fluxes Φ1 and Φx, respectively. These fluxes are superimposed within the magnetic core, increasing the mutual inductance M between L1 and Lx. The formula for calculating M is:

[0072]

[0073] The effective inductance value of L1 is: L1' = L1 + M; the effective inductance value of Lx is Lx' = Lx + M.

[0074] In an active power filter (APF), the maximum ripple current on the machine-side inductor L1 of the magnetic integrated inductor assembly 110 is calculated using the following formula:

[0075]

[0076] Where Ud is the capacitor voltage and fsw is the switching frequency. Compared to before adding the Lx coil, the ripple current is reduced by the following percentage:

[0077] Secondly, the core loss is determined by the magnetic flux density B generated by the ripple current and the frequency f, and the formula is as follows:

[0078] B = N * u * Isw / le

[0079] Where N is the number of turns in the coil, u is the permeability of the magnetic core, Isw is the ripple current, and le is the magnetic path length. The relationship between core loss and magnetic flux density and frequency is: Pl = aB b f c Where a, b, and c are loss coefficients. The reduction in core loss after introducing the Lx coil, compared to before adding the Lx coil, is as follows:

[0080] In the existing discrete inductor design 150, the number of copper wire turns of inductor L1 is: Where A1 is the inductance coefficient. In the magnetic integrated inductor assembly 110 of the embodiments of this disclosure, while maintaining the same inductance as the existing discrete inductor scheme 150, the number of copper wire turns of L1 is:

[0081]

[0082] Therefore, it can be seen that the magnetic integrated inductor solution can significantly reduce the proportion of copper wire used, and the reduction is as follows:

[0083]

[0084] Similarly, this process also applies to inductor Lx.

[0085] like Figure 3 As shown, the performance comparison between the integrated magnetic inductor assembly 110 and the discrete inductor solution 150 will be described below.

[0086] For example, taking KDM's High Flux series magnetic core as an example, assume L1 = 100uH, number of turns N1 = 10 turns; Lx = 9uH, number of turns Nx = 3 turns; mutual inductance between L1 and Lx M = 30uH; grid-side inductance L2 = 15μH; core loss coefficient b = 2.218; inverter capacitor voltage Ud = 800V; ripple current frequency fsw = 16kHz.

[0087] Calculations show that in discrete inductor scheme 150, the ripple current of inductor L1 is ΔI1 = 62.5, and the resonant capacitance is:

[0088]

[0089] In the magnetically integrated inductor assembly 110, the ripple current of inductor L1 is ΔI2 = 48.1 A. In comparison, the ripple current is reduced by 23%; the core loss is reduced by 44%. The resonant capacitance is:

[0090]

[0091] In terms of filtering characteristics, the performance of the low-frequency and mid-frequency bands is basically the same, but the magnetic integrated inductor component 110 improves the filtering effect in the high-frequency band.

[0092] like Figure 4 As shown, the following section uses KDM's High Flux series magnetic cores as an example to describe the performance comparison between the integrated magnetic inductor assembly 110 and the discrete inductor solution 150. The parameter settings for the integrated magnetic inductor assembly 110 and the existing discrete inductor solution 150 are as follows: machine-side inductance L1 = 100uH, resonant inductance Lx = 9uH, grid-side inductance L2 = 15uH, core loss coefficient b = 2.218, and assuming the inductance coefficients AL for L1 and Lx are 1uH / N. 2 The inverter capacitor voltage Ud = 800V, and the ripple current frequency fsw = 16kHz. Assuming the integrated magnetic inductor and discrete inductor are compared under the same ripple current conditions, the specific analysis is as follows:

[0093] In discrete inductor design 150, the number of turns of inductor L1 is: The number of turns of inductor Lx is:

[0094] In the magnetic integrated inductor assembly 110, the self-inductance of inductor L1 becomes: L1' = 72uH, and the number of turns of L1 is recalculated as: The actual number of turns is rounded to 9, which is 1 turn less than the discrete inductor solution of 150, reducing the copper wire cost by 10%. At this point, the self-inductance of L1 is further corrected to: L1' = AL * 9 2 =81uH; For inductor Lx, recalculate the self-inductance Lx' = 4.4uH and the number of turns as follows: The actual number of turns is rounded to 2 turns, which is 1 turn less than the discrete inductor solution of 150, reducing the copper wire cost by 33.3%. At this point, the self-inductance of Lx is further corrected to: Lx' = 4uH, and the mutual inductance between the two inductors L1' and Lx' is calculated as follows:

[0095]

[0096] In this way, the filtering performance in the low-frequency and mid-frequency ranges is basically the same in both the discrete inductor solution 150 and the magnetically integrated inductor assembly 110. However, the magnetically integrated inductor assembly 110 can improve the filtering effect in the high-frequency range and can more effectively suppress high-frequency ripple. In addition, since the core loss is directly related to the ripple current, the magnetically integrated inductor assembly 110 significantly reduces the ripple current, further reducing the core loss and improving the reliability and efficiency of the filter.

[0097] In addition, the magnetic integrated inductor assembly 110 reduces the amount of copper wire and core loss, significantly reducing manufacturing costs while ensuring filtering performance, improving the reliability and high-frequency filtering effect of the filter, and making it suitable for use in a variety of application scenarios.

[0098] Various implementations of this disclosure have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed implementations. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described implementations. The terminology used herein is chosen to best explain the principles, practical applications, or improvements to technology in the market, or to enable others skilled in the art to understand the various implementations disclosed herein.

Claims

1. A magnetically integrated inductor component for an LCL filter, characterized in that, include: The magnetic core (1101) has at least one magnetic circuit; The first winding (1111) and the second winding (1121) connected in series are wound at different magnetic circuit positions of the magnetic core (1101) and magnetically coupled and superimposed through at least one magnetic circuit of the magnetic core (1101). The first winding (1111) and the second winding (1121) are arranged such that the first winding (1111) forms a machine-side inductor (111) and the second winding (1121) forms a resonant inductor (112).

2. The magnetic integrated inductor assembly according to claim 1, characterized in that, The magnetic flux directions of the first winding (1111) and the second winding (1121) are the same.

3. The magnetic integrated inductor assembly according to claim 1, characterized in that, The magnetic core (1101) includes a ring structure, a square structure, or a CI type structure.

4. The magnetic integrated inductor assembly according to claim 1, characterized in that, The machine-side inductor (111) and the resonant inductor (112) are differential-mode inductors.

5. An LCL filter, characterized in that, include: According to any one of claims 1 to 4, the first output terminal of the first winding (1111) of the magnetic integrated inductor is electrically connected to the second input terminal of the second winding (1121); A first capacitor (120) is connected at its first end to the second output terminal of the second winding (1121) of the magnetic integrated inductor, and the second end of the first capacitor (120) is grounded. The second capacitor (130) has its third terminal electrically connected to the first output terminal and the second input terminal, and its fourth terminal grounded. as well as A grid-side inductor (140) is provided, the third input terminal of which is electrically connected to the first output terminal, the second input terminal and the third terminal of the second capacitor (130).

6. The LCL filter according to claim 5, characterized in that, Also includes: The machine side is electrically connected to the first input terminal of the first winding (1111), which is suitable for conducting the electrical connection with the inverter.

7. The LCL filter according to claim 5, characterized in that, Also includes: The grounding terminal is connected to the second terminal of the first capacitor (120) and the fourth terminal of the second capacitor (130).

8. The LCL filter according to claim 5, characterized in that, Also includes: The load end is electrically connected to the third output end of the grid-side inductor (140) and is adapted to conduct the electrical connection with the load.

9. The LCL filter according to claim 5, characterized in that, The first capacitor (120) is a differential mode capacitor.

10. The LCL filter according to claim 5, characterized in that, The second capacitor (130) is a differential mode capacitor.

Images