Inverter adopting electromagnetic compatibility design
By introducing electromagnetic compatibility (EMC) design into the inverter, including multiple filtering modules and isolation measures, the problem of strong electromagnetic interference in the inverter was solved, achieving improved EMC and reduced costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-14
- Publication Date
- 2026-04-17
AI Technical Summary
The lack of effective electromagnetic compatibility solutions in existing inverter designs leads to strong electromagnetic interference and increases the cost of subsequent EMC correction.
The inverter, designed with electromagnetic compatibility in mind, includes input and output electromagnetic interference filtering modules, a common-mode inductor, an inverter unit, an AC inductor-capacitor-inductor filtering module, a phase-shifting isolation three-phase transformer, and a control module. It suppresses common-mode noise through symmetrically wound dual coils, incorporates an AC LCL filter, and adds an input-side electromagnetic interference filtering module to ensure that signals are not interfered with during input and output. It uses fiber optic connections between the inverter unit and the control module, and separates the high-voltage and low-voltage sections. It also employs EMI filters and shielding design.
It effectively suppresses electromagnetic interference in the inverter, improves electromagnetic compatibility, reduces output voltage and current ripple, ensures signal continuity during input and output processes, and reduces the cost of EMC correction.
Smart Images
Figure CN224138896U_ABST
Abstract
Description
Technical Field
[0001] The embodiments disclosed herein belong to the field of inverter technology, and specifically relate to an inverter with electromagnetic compatibility design. Background Technology
[0002] An inverter is a device that converts direct current (DC) to alternating current (AC). Internally, an inverter contains both signal-level control circuitry and power-level main switching circuitry, resulting in a complex internal electromagnetic environment with strong conducted and radiated electromagnetic interference. Therefore, electromagnetic compatibility (EMC) issues must be fully considered during the structural design to reduce or avoid the costs associated with subsequent EMC correction devices.
[0003] In inverter design, electromagnetic compatibility (EMC) requirements are integrated into equipment selection. Based on EMC standards, specifications, and design principles, an EMC control plan is developed, employing measures such as shielding, grounding, filtering, and isolation to suppress EMC sources, cut off EMC coupling paths, and reduce the sensitivity of electromagnetically sensitive equipment. However, currently, there is a lack of effective solutions to inverter EMC problems.
[0004] Therefore, how to solve the above problems has become a technical problem that urgently needs to be solved by those skilled in the art. Utility Model Content
[0005] The embodiments disclosed herein are intended to at least address one of the technical problems existing in the prior art, and to provide an inverter with an electromagnetic compatibility design.
[0006] One aspect of the embodiments of this disclosure provides an inverter with electromagnetic compatibility design, including: an input-side electromagnetic interference filtering module, wherein the input terminal of the input-side electromagnetic interference filtering module is connected to a DC input interface;
[0007] A power switching unit, wherein the input terminal of the power switching unit is connected to the output terminal of the input-side electromagnetic interference filtering module;
[0008] A common-mode inductor, wherein the input terminal of the common-mode inductor unit is connected to the output terminal of the power switching unit;
[0009] An inverter unit, the input terminal of which is connected to the output terminal of the common-mode inductor unit;
[0010] An AC inductor-capacitor-inductor filter module is provided, wherein the input terminal of the AC inductor-capacitor-inductor filter module is connected to the output terminal of the inverter unit, and the output terminal of the AC inductor-capacitor-inductor filter module is connected to the AC load interface.
[0011] Furthermore, it also includes: an output-side electromagnetic interference filtering module, which is disposed at the output end of the AC inductor-capacitor-inductor filtering module, and the AC output from the output end of the AC inductor-capacitor-inductor filtering module is output to the AC load interface through the output-side electromagnetic interference filtering module.
[0012] Furthermore, it also includes: a phase-shifting isolation three-phase transformer, the input terminal of which is connected to the output terminal of the inverter unit, and the output terminal of which is connected to the input terminal of the AC inductor-capacitor-inductor filter module.
[0013] Furthermore, it also includes a control module, which is connected to the inverter unit via an optical fiber.
[0014] Optionally, the inverter further includes a composite busbar, wherein the input terminal of the inverter unit is connected to the output terminal of the common-mode inductor through the composite busbar, and the output terminal of the inverter unit is connected to the input terminal of the AC inductor-capacitor-inductor filter module through the composite busbar.
[0015] Optionally, the power switching unit has two DC input terminals;
[0016] The input-side electromagnetic interference filtering module includes a first electromagnetic interference filter and a second electromagnetic interference filter. The input terminal of the first electromagnetic interference filter is connected to a DC input interface, and the output terminal of the first electromagnetic interference filter is connected to one DC input terminal of the power switching unit. The input terminal of the second electromagnetic interference filter is connected to the DC input interface, and the output terminal of the second electromagnetic interference filter is connected to the other DC input terminal of the power switching unit.
[0017] Furthermore, it also includes: a power control module, the input terminal of which is connected to a power source, and the output terminal of which is connected to the power switching unit and the inverter unit respectively.
[0018] Furthermore, it also includes: a first filter and a second filter, wherein the input terminal of the first filter is connected to the power input interface, and the output terminal of the first filter is connected to the input terminal of the power control module;
[0019] The second filter is located at the output terminal of the power control module, and the second filter is used to filter the output current of the power control module.
[0020] Furthermore, it also includes: an analog signal input circuit, which includes a low-pass active filter and a software filter connected in series, the input end of the low-pass active filter being connected to the analog signal input port, and the output end of the software filter being connected to the control module.
[0021] Furthermore, it also includes: a low-voltage signal input circuit, which includes a third filter, a signal processing module, and a fourth filter connected in series. The input end of the third filter is connected to the low-voltage signal input port, the output end of the third filter is connected to the input end of the signal processing module, and the fourth filter is located at the output end of the signal processing module.
[0022] The beneficial effects of the embodiments of this disclosure include:
[0023] In this application, the common-mode inductor uses a symmetrically wound dual-coil design to suppress common-mode noise. The two sub-inductors of the common-mode inductor are respectively positioned at the positive and negative input terminals of the DC power line to ensure symmetry of the potentials of the positive and negative terminals relative to ground. An AC inductor-capacitor-inductor filter module (AC LCL filter) is installed on the AC side to reduce inverter output voltage and current ripple. An input-side electromagnetic interference filter module is added to the input terminal of the power switching unit to ensure continuous input current, thereby preventing electromagnetic interference to the signal during input and output and improving overall electromagnetic compatibility. Attached Figure Description
[0024] Figure 1 This is a schematic diagram of the circuit structure of an inverter with electromagnetic compatibility design according to an embodiment of the present disclosure;
[0025] Figure 2 This is a schematic diagram of the high-voltage circuit structure of an inverter with electromagnetic compatibility design according to an embodiment of the present disclosure;
[0026] Figure 3 This is a schematic diagram of the analog signal input circuit structure of an inverter with electromagnetic compatibility design according to an embodiment of the present disclosure;
[0027] Figure 4 This is a schematic diagram of the low-voltage signal input circuit structure of an inverter with electromagnetic compatibility design according to an embodiment of the present disclosure;
[0028] Figure 5 This is a schematic diagram of the power control circuit structure of an inverter with electromagnetic compatibility design according to an embodiment of the present disclosure.
[0029] In the diagram, 1. Input-side electromagnetic interference filtering module; 2. Power switching unit; 3. Common-mode inductor; 4. Inverter unit; 5. AC inductor-capacitor-inductor filtering module; 6. Output-side electromagnetic interference filtering module; 7. Phase-shifting isolation three-phase transformer; 8. Control module; 9. Power control module; 10. First filter; 11. Second filter; 12. Low-pass active filter; 13. Software filter; 14. Third filter; 15. Signal processing module; 16. Fourth filter; 17. First electromagnetic interference filter; 18. Second electromagnetic interference filter; 19. Optical fiber. Detailed Implementation
[0030] To enable those skilled in the art to better understand the technical solutions of this disclosure, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0031] The embodiments of this application will be further described in detail below with reference to the accompanying drawings and examples. The detailed descriptions and accompanying drawings of the following embodiments are used to exemplarily illustrate the principles of this application, but should not be used to limit the scope of this application; that is, this application is not limited to the described embodiments. In the description of this application, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," etc., indicating orientation or positional relationships are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. "Vertical" is not strictly vertical, but within the allowable error range. "Parallel" is not strictly parallel, but within the allowable error range.
[0032] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application depending on the specific circumstances.
[0033] like Figure 1-2As shown, an inverter designed with electromagnetic compatibility (EMC) includes an input-side EMC filtering module 1, a power switching unit 2, a common-mode inductor 3, an inverter unit 4, and an AC inductor-capacitor-inductor filtering module 5. The input terminal of the input-side EMC filtering module 1 is connected to a DC input interface, the input terminal of the power switching unit 2 is connected to the output terminal of the input-side EMC filtering module 1, and the input terminal of the common-mode inductor 3 is connected to the output terminal of the power switching unit 2.
[0034] The input terminal of the inverter unit 4 is connected to the output terminal of the common-mode inductor unit 3, the input terminal of the AC inductor-capacitor-inductor filter module 5 is connected to the output terminal of the inverter unit 4, and the output terminal of the AC inductor-capacitor-inductor filter module 5 is connected to the AC load interface. It can be understood that the above components constitute the high-voltage circuit of the inverter.
[0035] Common-mode inductor 3 uses symmetrically wound dual coils to suppress common-mode noise. The two sub-inductors in common-mode inductor 3 are respectively positioned at the positive and negative input terminals of the DC power line to ensure symmetry of the potential between the positive and negative terminals and ground. An AC inductor-capacitor-inductor filter module 5 (AC LCL filter) is installed on the AC side to reduce inverter output voltage and current ripple. An input-side electromagnetic interference filter module 1 is added to the input terminal of power switching unit 2 to ensure continuous input current, thereby preventing electromagnetic interference to the signal during input and output and improving overall electromagnetic compatibility.
[0036] In some embodiments, the input-side electromagnetic interference filtering module 1 is an EMI filter.
[0037] In some embodiments, the inverter further includes an output-side electromagnetic interference filtering module 6, which is disposed at the output terminal of the AC inductor-capacitor-inductor filtering module 5, and the AC output from the output terminal of the AC inductor-capacitor-inductor filtering module 5 is output to the AC load interface through the output-side electromagnetic interference filtering module 6.
[0038] In some embodiments, the inverter further includes a phase-shifting isolation three-phase transformer 7, the input terminal of which is connected to the output terminal of the inverter unit 4, and the output terminal of which is connected to the input terminal of the AC inductor-capacitor-inductor filter module 5.
[0039] In some embodiments, the inverter further includes a control module 8, which is connected to the inverter unit 4 via an optical fiber 19.
[0040] In some embodiments, the inverter further includes a composite busbar, wherein the input terminal of the inverter unit 4 is connected to the output terminal of the common-mode inductor 3 through the composite busbar, and the output terminal of the inverter unit 4 is connected to the input terminal of the AC inductor-capacitor-inductor filter module 5 through the composite busbar.
[0041] In some embodiments, the power switching unit 2 has two DC input terminals.
[0042] The input-side electromagnetic interference filtering module 1 includes a first electromagnetic interference filter 17 and a second electromagnetic interference filter 18. The input terminal of the first electromagnetic interference filter 17 is connected to a DC input interface, and the output terminal of the first electromagnetic interference filter 17 is connected to one DC input terminal of the power switching unit 2. The input terminal of the second electromagnetic interference filter 18 is connected to a DC input interface, and the output terminal of the second electromagnetic interference filter 18 is connected to the other DC input terminal of the power switching unit 2.
[0043] In some embodiments, reference is made to Figure 5 The inverter also includes a power control module 9, the input of which is connected to a power source, and the output of which is connected to the power switching unit 2 and the inverter unit 4, respectively.
[0044] In some embodiments, the inverter further includes a first filter 10 and a second filter 11, the input of the first filter 10 being connected to a power input interface, and the output of the first filter 10 being connected to the input of the power control module 9.
[0045] The second filter 11 is disposed at the output terminal of the power control module 9, and the second filter 11 is used to filter the output current of the power control module 9. The power control module 9, the first filter 10, and the second filter 11 together constitute a power control loop. Specifically, the power control loop is used to supply power to at least the power switching unit 2 and the inverter unit 4.
[0046] In some embodiments, reference is made to Figure 3 The inverter also includes an analog signal input circuit, which comprises a low-pass active filter 12 and a software filter 13 connected in series. The input terminal of the low-pass active filter 12 is connected to the analog signal input port, and the output terminal of the software filter 13 is connected to the control module 8. Specifically, the analog signal output from the analog signal input circuit is output to the power switching unit 2 and the inverter unit 4.
[0047] In some embodiments, reference is made to Figure 4The inverter also includes a low-voltage signal input circuit, which comprises a third filter 14, a signal processing module 15, and a fourth filter 16 connected in series. The input terminal of the third filter 14 is connected to the low-voltage signal input port, and the output terminal of the third filter 14 is connected to the input terminal of the signal processing module 15. The fourth filter 16 is located at the output terminal of the signal processing module 15. Specifically, the low-voltage signal output from the low-voltage signal input circuit is output to the power switching unit 2 and the inverter unit 4.
[0048] Specifically, the following measures were taken during the inverter design process to improve electromagnetic compatibility:
[0049] 1) Through mathematical modeling and theoretical derivation, the operating point corresponding to the minimum total harmonic coefficient of the inverter output voltage is calculated to reduce the harmonic content of each electrical quantity in the main circuit.
[0050] 2) The DC filter inductor is a common-mode inductor 3. Common-mode noise is suppressed by symmetrically wound double coils. The two sub-inductors are arranged on the positive and negative terminals of the DC input respectively to ensure the symmetry of the DC positive and negative terminals with respect to ground potential.
[0051] 3) An AC inductor-capacitor-inductor filter module 5 (AC LCL filter) is installed on the AC side to minimize the inverter output voltage and current ripple.
[0052] 4) The dual-channel DC power supply switching unit 2 adds an input-side electromagnetic interference filtering module 1 to ensure continuous input current as much as possible.
[0053] 5) To improve the anti-interference capability of the system, the analog input signal in the analog signal input circuit is first filtered by the low-pass active filter 12 before analog-to-digital conversion, and then filtered again by the software filter 13 after sampling.
[0054] 6) In the low-voltage signal input circuit, the signal input and output, as well as the control signal, are all filtered by filters to ensure that the signal is not disturbed during the input and output process.
[0055] 7) EMI filters are installed on both the input and output lines of the control power module;
[0056] 8) The inverter unit 4 and the control module 8 are connected by optical fiber 19 to solve the problems of anti-interference and electrical isolation.
[0057] 9) The inverter’s signal ground is floating, so it is completely independent of the strong and weak current circuits. The electromagnetic compatibility ground is not electrically connected to the signal ground or the strong current circuit. It is connected to the converter cabinet in a two-point grounding manner.
[0058] 10) In the inverter, since there are two voltage levels, high voltage circuit and low voltage control, the low voltage part and the high voltage part are set up in separate areas. The high voltage and low voltage lines are separated in the wiring to reduce the radiation interference of the high voltage part to the low voltage control part.
[0059] The above design ensures the self-compatibility of the high-voltage and low-voltage components inside the inverter.
[0060] Radiation interference resistant design
[0061] 1) The server rack employs a shielded design to suppress various electromagnetic interferences propagating through space. Typically, signal indicator lights and other equipment need to be installed on the rack's panel, inevitably requiring holes and openings. These openings compromise the integrity of the shielding structure, causing electromagnetic leakage. Therefore, additional metal mesh is added at these openings for shielding.
[0062] 2) The inverter's input and output cables are connected to the cabinet through stuffing boxes, and its shielding layer is also connected to the cabinet through stuffing boxes. EMI filters are added to both the input and output sides of the inverter.
[0063] 3) A phase-shifting isolation three-phase transformer 7 is set between the inverter unit 4 and the AC inductor-capacitor-inductor filter module 5. The carrier phase-shifting design between the three phases ABC is adopted to greatly reduce the amplitude of the output common-mode voltage.
[0064] 4) The composite busbar design reduces stray inductance in the circuit, alleviates the switching stress of the inverter IGBT module, and ensures reliable module operation.
[0065] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.
Claims
1. An inverter employing electromagnetic compatibility design, characterized by, include: An input-side electromagnetic interference filtering module, wherein the input terminal of the input-side electromagnetic interference filtering module is connected to a DC input interface; A power switching unit, wherein the input terminal of the power switching unit is connected to the output terminal of the input-side electromagnetic interference filtering module; A common-mode inductor, wherein the input terminal of the common-mode inductor unit is connected to the output terminal of the power switching unit; An inverter unit, the input terminal of which is connected to the output terminal of the common-mode inductor unit; An AC inductor-capacitor-inductor filter module is provided, wherein the input terminal of the AC inductor-capacitor-inductor filter module is connected to the output terminal of the inverter unit, and the output terminal of the AC inductor-capacitor-inductor filter module is connected to the AC load interface.
2. The electromagnetic compatibility design adopted inverter according to claim 1, characterized in that, Also includes: An output-side electromagnetic interference filtering module is provided, which is located at the output end of the AC inductor-capacitor-inductor filtering module, and the AC output from the output end of the AC inductor-capacitor-inductor filtering module is output to the AC load interface through the output-side electromagnetic interference filtering module.
3. The inverter with electromagnetic compatibility design according to claim 1, characterized in that, Also includes: A phase-shifting isolation three-phase transformer is provided, the input terminal of which is connected to the output terminal of the inverter unit, and the output terminal of which is connected to the input terminal of the AC inductor-capacitor-inductor filter module.
4. The electromagnetic compatibility design adopted inverter according to claim 1, characterized in that, Also includes: A control module is connected to the inverter unit via an optical fiber.
5. The electromagnetic compatibility design adopted inverter according to claim 1, characterized in that, The inverter also includes a composite busbar, wherein the input terminal of the inverter unit is connected to the output terminal of the common-mode inductor through the composite busbar, and the output terminal of the inverter unit is connected to the input terminal of the AC inductor-capacitor-inductor filter module through the composite busbar.
6. The inverter with electromagnetic compatibility design according to claim 1, characterized in that, The power switching unit has two DC input terminals; The input-side electromagnetic interference filtering module includes a first electromagnetic interference filter and a second electromagnetic interference filter. The input terminal of the first electromagnetic interference filter is connected to a DC input interface, and the output terminal of the first electromagnetic interference filter is connected to one DC input terminal of the power switching unit. The input terminal of the second electromagnetic interference filter is connected to the DC input interface, and the output terminal of the second electromagnetic interference filter is connected to the other DC input terminal of the power switching unit.
7. The electromagnetic compatibility design adopted inverter according to claim 1, characterized in that, Also includes: The power control module has its input terminal connected to a power source and its output terminal connected to both the power switching unit and the inverter unit.
8. The electromagnetic compatibility design adopted inverter according to claim 7, characterized in that, Also includes: A first filter and a second filter, wherein the input terminal of the first filter is connected to the power input interface, and the output terminal of the first filter is connected to the input terminal of the power control module; The second filter is located at the output terminal of the power control module, and the second filter is used to filter the output current of the power control module.
9. The electromagnetic compatibility design adopted inverter according to claim 4, characterized in that, Also includes: An analog signal input circuit includes a low-pass active filter and a software filter connected in series. The input terminal of the low-pass active filter is connected to the analog signal input port, and the output terminal of the software filter is connected to the control module.
10. The electromagnetic compatibility design adopted inverter according to claim 4, characterized in that, Also includes: The weak electric signal input circuit comprises a third filter, a signal processing module and a fourth filter connected in series, an input end of the third filter is connected with a weak electric signal input port, an output end of the third filter is connected with an input end of the signal processing module, and the fourth filter is arranged at an output end of the signal processing module.