Low-voltage source electromagnetic compatibility system and motor controller

Abstract

The invention relates to a low-voltage source electromagnetic compatibility system and a motor controller, and relates to the technical field of automotive electronics, and the low-voltage source electromagnetic compatibility system comprises a positive pole input end, a positive pole output end, a negative pole input end, a negative pole output end, a positive pole power supply access, a negative pole power supply access, a pair of differential mode inductors and n differential mode capacitors, the anode power supply access is connected with the anode input end and the anode output end; the cathode power supply access is connected with the cathode input end and the cathode output end; the pair of differential mode inductors are connected in series to the positive electrode power supply path one by one; the capacitance values of the n differential-mode capacitors are kept consistent, the n differential-mode capacitors are connected between the positive electrode power supply access and the negative electrode power supply access in a bridging mode one by one, n is set to be 2-5, and the differential-mode inductors and the differential-mode capacitors are evenly distributed in a crossed mode; the negative electrode power supply access is a low-impedance direct-current access which is from the negative electrode input end to the negative electrode output end and does not contain any series inductor. The broadband electromagnetic interference suppression circuit has the advantages of compact size, low cost and capability of effectively suppressing broadband electromagnetic interference.

Description

Technical Field

[0001] This application relates to the field of automotive electronics technology, and in particular to a low-voltage source electromagnetic compatibility system and a motor controller. Background Technology

[0002] With the rapid development of vehicle electrification, intelligence, and connectivity, the number of electronic control units (ECUs) integrated within vehicles has increased dramatically, leading to an increasingly complex electromagnetic environment. As one of the core "three-electric" components of new energy vehicles, the motor controller integrates high-voltage power modules, microcontrollers, and low-voltage DC-DC converters to power these devices. These components inevitably generate wideband electromagnetic interference during operation, covering a spectrum from 150kHz to 1GHz. This mainly includes:

[0003] 1. High-voltage side coupling interference: The switching action of high-voltage components generates high dv / dt transients, which are coupled to low-voltage circuits through spatial radiation or common ground paths;

[0004] 2. Inherent interference on the low-voltage side: inductor current ripple in the buck / boost circuit and high-frequency harmonics of the oscillator. Interference frequency domain characteristics:

[0005] 3. Interference frequency domain characteristics: The interference spectrum covers 150kHz-1GHz. In the low frequency band (<10MHz), differential mode conduction is the main feature, while in the high frequency band, common mode radiation is the main feature.

[0006] International standards CISPR25 and GB18655 impose stringent requirements on the electromagnetic compatibility performance of vehicle-mounted electronic equipment.

[0007] Existing technologies mainly employ filtering schemes using cascaded multi-stage common-mode inductors, which have the following drawbacks:

[0008] 1. Large size and significant space occupation: To achieve sufficient inductance and common-mode rejection capability, common-mode inductors typically use high-permeability ferrite cores and require double-wire winding, resulting in a physical size significantly larger than differential-mode inductors of the same current rating. For example, a typical automotive-grade common-mode inductor, such as the TDK ZJYS series, can reach a single-chip size of 19mm × 12mm × 12mm. Laying out 2 to 3 such inductors on a PCB can result in the filter section alone occupying over 1000mm² of space. 2 The area consumed more than 600mm² 3 This is in contrast to the fact that the PCB area of ​​the power module in modern motor controllers is strictly limited to 800mm². 2 This runs counter to the miniaturization trend (refer to SAE J1455 standard) and greatly limits the compactness of product design.

[0009] 2. Parasitic resonance effect leading to high-frequency filter failure: When multiple common-mode inductors are physically arranged in series, the distributed capacitance of the windings between inductors and the parasitic capacitance between the inductors and the PCB traces will form an LC parallel resonant circuit. This causes a resonant point shift (typically 2-5MHz), resulting in a drop in insertion loss of >15dB in this frequency band, and consequently, poor overall product test results.

[0010] In summary, while the multi-stage common-mode inductor filtering schemes widely used in existing technologies can provide a certain filtering effect under specific conditions, their three fundamental defects—size, cost, and resonance failure—make them increasingly difficult to meet the stringent requirements of modern automotive motor controllers and other high-performance electronic control units for miniaturization, low cost, and full-band reliability. Summary of the Invention

[0011] The purpose of this invention is to overcome the above-mentioned defects of the prior art and provide a low-voltage source electromagnetic compatibility system and motor controller, which aims to solve the technical problems of large size and resonance failure in key frequency bands (such as 2-5MHz) caused by the use of multi-level common mode inductor schemes in the prior art.

[0012] Firstly, the low-voltage source electromagnetic compatibility system provided in this application adopts the following technical solution:

[0013] A low-voltage source electromagnetic compatibility system includes a positive input terminal, a positive output terminal, a negative input terminal, a negative output terminal, and:

[0014] A positive power supply path, which connects the positive input terminal and the positive output terminal;

[0015] A negative power supply path, which connects the negative input terminal and the negative output terminal;

[0016] A pair of differential-mode inductors are connected in series one after the other in the positive power supply path;

[0017] n differential-mode capacitors, all with the same capacitance value, are connected one by one between the positive power supply path and the negative power supply path;

[0018] Wherein, n is set to 2 to 5, and the differential mode inductor and the differential mode capacitor are evenly distributed in a cross pattern;

[0019] The negative power supply path is a low-impedance DC path from the negative input terminal to the negative output terminal, which does not contain any series inductance.

[0020] By adopting the above solution, the problems of excessive size, high cost, and resonance failure caused by the use of common-mode inductors in traditional electromagnetic compatibility solutions are solved, achieving interference suppression across the entire frequency band from 150kHz to 200MHz at the low-voltage power supply port. This solution, through optimized differential-mode component layout and low-impedance design of the negative electrode path, ensures filtering performance while meeting the core requirements of automotive electronic equipment for miniaturization and high cost-effectiveness.

[0021] Furthermore, the differential mode capacitor includes m capacitors connected in parallel, where m is set to 3 to 6.

[0022] By adopting the above scheme, effective suppression of wide-band electromagnetic interference is achieved, solving the problems of incomplete frequency coverage and resonance risk caused by a single capacitor value. Through the gradient configuration of the number and capacitance of parallel capacitors, a multi-band collaborative filtering mechanism is formed within a limited space, which not only improves the bypass capability of high-frequency noise but also avoids the negative impact of complex layout on filtering performance.

[0023] Furthermore, the m capacitors are arranged sequentially along the current direction within the positive power supply path, and their capacitance values ​​decrease in a gradient of 10 to 100 times.

[0024] By adopting the above solution, the problem of resonance suppression failure caused by improper capacitor configuration was solved, and the gradual absorption of broadband noise energy was achieved. The transmission path of high-frequency noise was significantly shortened, improving the high-frequency filtering efficiency. At the same time, the gradient capacitance layout optimized the PCB space utilization and avoided space waste caused by disordered arrangement.

[0025] Furthermore, the differential mode capacitor includes a first capacitor, a second capacitor, a third capacitor, and a fourth capacitor arranged sequentially along the current direction in the positive power supply path. The first capacitor is set to 1-10μF, the second capacitor is set to 50-500nF, the third capacitor is set to 1-10nF, and the fourth capacitor is set to 100-800pF.

[0026] The above technical solution effectively suppresses differential-mode interference across the entire frequency band from 150kHz to 200MHz, solves the technical defects of traditional filter networks in high-frequency band failure and multi-capacitor resonance, and optimizes the absorption path of noise energy in different frequency bands through a stepped layout.

[0027] Furthermore, the negative power supply path is configured as a ground plane, which is connected to the ground terminal of the differential mode capacitor and the metal casing of the motor controller to provide a low-impedance return path for common mode noise.

[0028] The above technical solution solves the problem of insufficient suppression of common-mode noise caused by excessively high return path impedance. By optimizing the grounding structure, the loop impedance of high-frequency noise is reduced, and the resonance risk caused by grounding distributed parameters is avoided, thereby improving the stability of electromagnetic compatibility performance.

[0029] Furthermore, the pair of differential mode inductors includes a first inductor and a second inductor, wherein the inductance values ​​of the first inductor and the second inductor are consistent.

[0030] The above technical solution achieves stable suppression of differential mode noise across the entire frequency band, while avoiding the risk of electromagnetic compatibility test failure caused by resonance failure, thus improving the reliability of the system under complex operating conditions.

[0031] Furthermore, the inductance values ​​of the first inductor and the second inductor are set to 5–15 μH.

[0032] The above technical solution effectively avoids the resonance failure problem caused by improper inductor parameters in traditional solutions. The optimized inductance value ensures that the filter network exhibits stable impedance characteristics within the target frequency band, guaranteeing reliable compliance with electromagnetic compatibility standards. Furthermore, the differential-mode inductor and differential-mode capacitor are surface-mount type.

[0033] The above technical solutions achieve high-density integrated design of electromagnetic compatibility systems, improve high-frequency noise suppression by eliminating lead parasitic parameters, and support fully automated production processes through standardized packaging.

[0034] Furthermore, a transient voltage suppression unit is connected between the positive power supply path and the negative power supply path. The transient voltage suppression unit is connected in parallel between the positive input terminal and the negative input terminal to absorb the surge voltage at the input terminal.

[0035] The above technical solution effectively solves the problem of electronic component breakdown caused by surge voltage at the power input terminal. The graded protection mechanism improves system reliability without excessively increasing circuit complexity. The coordinated operation of the transient suppression unit and the subsequent filter network not only blocks the direct impact of high-voltage pulses on sensitive devices but also maintains the stability of steady-state filtering performance.

[0036] Secondly, the motor controller provided in this application adopts the following technical solution:

[0037] A motor controller includes a main controller power module, a drive power module, and the aforementioned low-voltage source electromagnetic compatibility system. The drive power module is connected to the main controller power module. The input terminal of the low-voltage source electromagnetic compatibility system is connected to the low-voltage battery of an electric vehicle, and the output terminal of the low-voltage source electromagnetic compatibility system is connected to the input terminal of the main controller power module.

[0038] In summary, this application includes at least one of the following beneficial technical effects:

[0039] This application provides a low-voltage source electromagnetic compatibility system and motor controller, which uses a cross-distributed differential-mode inductor and differential-mode capacitor, combined with a low-impedance DC path on the negative pole, to significantly reduce the size and cost of the device while ensuring electromagnetic compatibility performance. It avoids the resonance valley problem caused by multi-level common-mode inductors and has the advantages of compact size, low cost and effective suppression of broadband electromagnetic interference. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the circuit structure of a low-voltage source electromagnetic compatibility system;

[0041] Figure 2 This is a graph showing the positive electrode results from the voltage method test;

[0042] Figure 3 This is a graph showing the negative electrode result from the voltage method test;

[0043] Figure 4 This is a graph showing the results of the current method test;

[0044] Figure 5 This is a diagram showing the results of the radiation field test.

[0045] In the diagram, 100 is the positive input terminal; 200 is the positive output terminal; 300 is the negative input terminal; 400 is the negative output terminal; 500 is the positive power supply path; 600 is the negative power supply path; 700 is the differential mode inductor; 710 is the first inductor; 720 is the second inductor; 800 is the differential mode capacitor; 810 is the first capacitor; 820 is the second capacitor; 830 is the third capacitor; 840 is the fourth capacitor; and 900 is the transient voltage suppression unit. Detailed Implementation

[0046] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of this application.

[0047] Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0048] In existing technologies, the electromagnetic compatibility design of the low-voltage power supply port of automotive electronic control power generation systems commonly employs a multi-stage common-mode inductor filtering scheme. This type of scheme relies on a filter network composed of series-connected common-mode inductors and capacitors, but it suffers from problems such as large size, high cost, and resonance caused by multiple inductors. With the increasing demand for miniaturization and high cost-effectiveness in automotive electronic devices, traditional solutions are failing to meet modern design requirements due to excessive space requirements, high material costs, and filtering failure in specific frequency bands.

[0049] To address the aforementioned issues, the inventors noted that the core flaw of traditional solutions stemmed from the inherent characteristics of common-mode inductors, and thus explored the possibilities of combining differential-mode components. By analyzing the conduction path of differential-mode interference, they discovered that differential-mode noise in the positive circuit was the primary source of interference, while maintaining low impedance in the negative circuit effectively diverted common-mode current. Based on this, they proposed connecting a differential-mode inductor in series with multiple capacitors in the positive circuit, while eliminating inductive components in the negative circuit, thereby constructing a compact filter architecture. This approach avoids the use of common-mode inductors, instead achieving full-band suppression through differential-mode component placement and negative circuit path optimization.

[0050] Example 1:

[0051] Reference Figure 1 This embodiment 1 proposes a low-voltage source electromagnetic compatibility system, including a positive input terminal 100, a positive output terminal 200, a negative input terminal 300, a negative output terminal 400, a positive power supply path 500, a negative power supply path 600, a pair of differential-mode inductors 700, and multiple differential-mode capacitors 800. The positive power supply path 500 connects the positive input terminal 100 and the positive output terminal 200, and the negative power supply path 600 connects the negative input terminal 300 and the negative output terminal 400. The differential-mode inductors 700 are connected in series with the positive power supply path 500, and the multiple differential-mode capacitors 800 are connected across the positive power supply path 500 and the negative power supply path 600, and are evenly distributed and intersecting with the differential-mode inductors 700.

[0052] The positive power supply path 500 refers to the conductive path through which current flows from the positive input terminal 100 to the positive output terminal 200. The form of the positive power supply path 500 can be specifically configured according to actual conditions. For example, the positive power supply path 500 and the negative power supply path 600 are made of copper wire.

[0053] Furthermore, the negative power supply path 600 is a low-impedance DC path from the negative input terminal 300 to the negative output terminal 400, which does not contain any series inductance. The form of the negative power supply path 600 can be specifically configured according to the actual situation. For example, the negative power supply path 600 is set as a ground plane to reduce the return impedance of the common-mode current.

[0054] The ground plane is connected to the ground terminal of the differential mode capacitor 800 and the metal casing of the motor controller, providing a low-impedance return path for common mode noise.

[0055] After common-mode noise enters the ground plane through the ground terminal of the differential-mode capacitor 800, it returns directly to the interference source through the metal casing, forming a closed loop. This solves the problem of insufficient suppression of common-mode noise caused by excessively high return path impedance. By optimizing the grounding structure, the loop impedance of high-frequency noise is reduced, while avoiding the resonance risk caused by grounding distributed parameters, thus improving the stability of electromagnetic compatibility performance.

[0056] A differential-mode inductor 700 is a magnetic component that presents high impedance only to differential-mode current, used to filter out differential-mode noise in a system. A differential-mode capacitor 800 is a capacitive component connected between the positive and negative terminals. The capacitance value of the differential-mode capacitor 800 is kept consistent to achieve balanced filtering, used to absorb differential-mode interference in different frequency bands.

[0057] For ease of explanation, the differential mode inductor 700 will be denoted as L, and the differential mode capacitor 800 will be denoted as C.

[0058] The number of differential mode capacitors 800 is n, where n can be set to 2 to 5. The specific number can be set according to the actual situation; for example, n can be set to 2, 3, 4, or 5.

[0059] For example, the number of differential mode capacitors 800 is set to 2, and the distribution of differential mode inductors 700 and differential mode capacitors 800 is: LCLC.

[0060] For example, the number of differential mode capacitors 800 is set to 3, and the distribution of differential mode inductors 700 and differential mode capacitors 800 is: CLCLC.

[0061] The number of differential-mode capacitors 800 is set to three, and the staggered distribution means that the differential-mode inductor 700 and differential-mode capacitor 800 are arranged alternately along the positive terminal line. For the specific arrangement, please refer to [reference needed]. Figure 1 The spacing between the differential-mode inductor 700 and the differential-mode capacitor 800 is set to 5–8 mm to optimize the high-frequency noise attenuation path and reduce the loop area. The specific spacing value can be adjusted according to the actual situation, for example, 5 mm, 6 mm, 7 mm, or 8 mm.

[0062] For example, the spacing between the differential mode inductor 700 and the differential mode capacitor 800 is set to 6 mm.

[0063] A differential-mode inductor 700 and a bridging differential-mode capacitor 800 form a multi-stage LC filter structure. The differential-mode inductor 700 suppresses sudden changes in differential-mode current in the positive circuit, while the bridging capacitor shuns high-frequency noise to the negative circuit. The low-impedance design of the negative circuit ensures rapid discharge of common-mode current, avoiding additional resonance introduced by inductive components. The cross-layout of the differential-mode inductor 700 and the capacitor shortens the loop area for high-frequency noise, while the parallel connection of multiple capacitors extends the filtering bandwidth. Through the synergistic effect of the positive differential-mode filter chain and the negative low-impedance path, the system achieves wideband interference suppression without using a common-mode inductor.

[0064] The compact combination of the differential-mode inductor 700 and capacitor significantly reduces space occupation. Furthermore, the negative DC path design eliminates inductors to optimize common-mode noise conduction. Additionally, the alternating arrangement of differential-mode components avoids multi-stage inductor coupling, thereby eliminating resonant frequencies.

[0065] Furthermore, the differential mode inductor 700 is configured as a surface mount type.

[0066] Specifically, the 700 surface-mount differential mode inductor replaces the traditional wire-wound structure with a one-piece molding process, eliminating the volume redundancy caused by the wire-wound gap. Its planar packaging allows the inductor height to fit snugly against the PCB surface, reducing the space occupied in the vertical direction.

[0067] Notably, the differential mode inductor 700 adopts a miniature surface-mount integrated design, with dimensions of 8.2mm × 7.5mm, reducing the PCB footprint required for system connections from 1200mm². 2 Reduced to 600mm 2 This significantly reduces the space required. The differential mode inductor 700 uses an Fe-Si-Al alloy magnetic powder core, and its temperature rise is less than 25℃ under 5A full load conditions, further improving the thermal stability of the system.

[0068] Furthermore, based on the surface mount design of the differential mode inductor 700, the differential mode capacitor 800 is further configured as a surface mount to optimize the space layout.

[0069] Furthermore, the differential-mode capacitor 800 includes m capacitors connected in parallel, where m is set to 3 to 6. The m capacitors are arranged sequentially along the current direction within the positive power supply path 500, and their capacitance values ​​decrease in a gradient of 10 to 100 times.

[0070] Specifically, in the current transmission direction of the positive power supply path 500, multiple capacitors are arranged sequentially in descending order of capacitance to form a cascaded filter structure. Large-capacitance capacitors are placed near the power input terminal to absorb high-energy noise in the low-frequency band; medium-capacitance capacitors are placed in the middle section to suppress intermediate-frequency interference; and small-capacitance capacitors are placed near the output terminal to filter high-frequency noise.

[0071] The decreasing capacitance values ​​result in low impedance characteristics for each capacitor within a specific frequency band, allowing noise from different frequency bands to be filtered out step by step. Simultaneously, because the physical location of the capacitors aligns with the current direction, the transmission path of high-frequency noise is effectively shortened, avoiding the parasitic inductance superposition problem caused by traditional disordered arrangements. Through parallel combinations of capacitors with different capacitance values, the equivalent series inductance is canceled out, thereby suppressing impedance abrupt changes and resonance risks caused by a single capacitor in a specific frequency band.

[0072] Furthermore, limiting the number of capacitors to a suitable range is crucial to cover a wideband interference range of 150kHz to 200MHz while avoiding frequency band gaps due to an insufficient number or parasitic capacitance accumulation caused by an excessive number. The specific number of capacitors can be set according to actual conditions; for example, m can be set to 3, 4, or 5 or more.

[0073] For example, m is set to 4.

[0074] Based on the above example, correspondingly, capacitance values ​​of different orders of magnitude, such as microfarads, nanofarads, and picofarads, are selected to form a filtering effect with progressive attenuation.

[0075] Specifically, the differential mode capacitor 800 includes a first capacitor 810, a second capacitor 820, a third capacitor 830, and a fourth capacitor 840 arranged sequentially along the current direction within the positive power supply path 500. The first capacitor 810 is set to 1-10μF, the second capacitor 820 is set to 50-500nF, the third capacitor 830 is set to 1-10nF, and the fourth capacitor 840 is set to 100-800pF.

[0076] Four capacitors are arranged sequentially along the current transmission direction to form a stepped filter network, which optimizes the absorption path of noise energy in different frequency bands.

[0077] The large capacitance of the first capacitor 810 makes it exhibit low impedance in the 150kHz to 1MHz frequency band, preferentially filtering out low-frequency conducted interference; the medium capacitance of the second capacitor 820 covers the 1MHz to 10MHz frequency band, attenuating the periodic pulse noise generated by switching devices; the small capacitance design of the third capacitor 830 enables it to work effectively in the 10MHz to 50MHz frequency band, suppressing high-frequency harmonic components; the extremely small capacitance of the fourth capacitor 840 is specifically designed for the 50MHz to 200MHz frequency band, eliminating radio frequency interference introduced by radiated coupling.

[0078] Furthermore, the pair of differential mode inductors 700 includes a first inductor 710 and a second inductor 720, wherein the inductance values ​​of the first inductor 710 and the second inductor 720 are consistent.

[0079] By setting the inductance values ​​of the first inductor 710 and the second inductor 720 to the same value, the two inductors form a symmetrical impedance distribution on the positive power supply path 500. In the differential-mode noise transmission path, the superposition of the inductive reactance generated by the two inductors can effectively suppress broadband interference signals, while avoiding the resonant network mismatch problem caused by the difference in inductance parameters.

[0080] When the inductance values ​​are consistent, the filter network formed by the two-stage inductor and the bridging capacitor has uniform cutoff frequency characteristics, thereby ensuring a smooth transition of the insertion loss curve of the differential-mode filter link in the target frequency band and eliminating the resonant frequency shift caused by the discreteness of inductor parameters in traditional schemes.

[0081] Furthermore, the inductance values ​​of the first inductor 710 and the second inductor 720 are set to 1-50μH. In a specific embodiment, the inductance values ​​of the first inductor 710 and the second inductor 720 can be further reduced to 5-15μH.

[0082] By reducing the inductance of the 700 ohm differential-mode inductor to the microhenry level and combining this with topology reconstruction of the differential-mode filter path, the resonant frequency is increased to over 50MHz to avoid critical interference frequency bands. This ensures that the filter network exhibits stable impedance characteristics within the target frequency band, guaranteeing reliable compliance with electromagnetic compatibility standards.

[0083] Furthermore, a transient voltage suppression unit 900 is connected between the positive power supply path 500 and the negative power supply path 600. The transient voltage suppression unit 900 is connected in parallel between the positive input terminal 100 and the negative input terminal 300 to absorb the surge voltage at the input terminal.

[0084] Specific reference Figure 3The transient voltage suppression unit 900 refers to an overvoltage protection device connected in parallel between the power input port and the ground terminal. In a specific embodiment, the transient voltage suppression unit 900 can be implemented using a bidirectional transient voltage suppression diode or a varistor, and its response time is controlled in the nanosecond range to quickly clamp voltage surges. This unit is directly connected to the power input terminal, which can form a discharge path before surge energy enters the subsequent filtering circuit, avoiding cumulative damage to the inductor winding and capacitor dielectric caused by high voltage pulses.

[0085] For example, the transient voltage suppression unit 900 employs a surface-mount packaged transient voltage suppression diode.

[0086] For example, the transient voltage suppression unit 900 employs a varistor.

[0087] The following is about Figure 1 The electromagnetic compatibility system shown was tested to verify its performance. The tests included voltage method testing, current method testing, and radiated field testing.

[0088] Among them, the positive electrode data from the voltage method test are as follows: Figure 2 As shown, the negative electrode data obtained by the voltage method are as follows: Figure 3 As shown, the current method test results are as follows: Figure 4 As shown, the radiation field test results are as follows: Figure 5 As shown.

[0089] Based on simulation calculations and multiple test results, it can be seen that the solution can meet the test requirements well under multiple test items, and the results of each test frequency band have a margin, which well meets the test requirements of automotive electronic control power generation system.

[0090] Example 2:

[0091] A motor controller includes a main controller power module, a drive power module, and a low-voltage source electromagnetic compatibility system. The input terminal of the low-voltage source electromagnetic compatibility system is connected to the low-voltage battery of the electric vehicle, and the output terminal of the low-voltage source electromagnetic compatibility system is connected to the input terminal of the main controller power module.

[0092] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, all equivalent changes made to the structure, shape, and principle of this application should be included within the scope of protection of this application.

Claims

1. A low-voltage source electromagnetic compatibility system, characterized in that, Includes a positive input terminal (100), a positive output terminal (200), a negative input terminal (300), a negative output terminal (400), and: A positive power supply path (500) connects the positive input terminal (100) and the positive output terminal (200); A negative power supply path (600) connects the negative input terminal (300) and the negative output terminal (400); A pair of differential mode inductors (700) are connected in series in the positive power supply path (500); n differential-mode capacitors (800) with the same capacitance value are connected one by one between the positive power supply path (500) and the negative power supply path (600); Wherein, n is set to 2 to 5, and the differential mode inductor (700) and the differential mode capacitor (800) are evenly distributed in a cross pattern; The negative power supply path (600) is a low-impedance DC path from the negative input terminal (300) to the negative output terminal (400) that does not contain any series inductance.

2. The system according to claim 1, characterized in that, The differential mode capacitor (800) includes m capacitors connected in parallel, where m is set to 3 to 6.

3. The system according to claim 2, characterized in that, The m capacitors are arranged sequentially along the current direction in the positive power supply path (500), and the capacitance values ​​are arranged in a gradient decreasing by 10 to 100 times.

4. The system according to claim 3, characterized in that, The differential mode capacitor (800) includes a first capacitor (810), a second capacitor (820), a third capacitor (830), and a fourth capacitor (840) arranged sequentially along the current direction in the positive power supply path (500). The first capacitor (810) is set to 1-10μF, the second capacitor (820) is set to 50-500nF, the third capacitor (830) is set to 1-10nF, and the fourth capacitor (840) is set to 100-800pF.

5. The system according to claim 1, characterized in that, The negative power supply path (600) is set as a ground plane, which is connected to the ground terminal of the differential mode capacitor (800) and the metal casing of the motor controller to provide a low impedance return path for common mode noise.

6. The system according to claim 1, characterized in that, The pair of differential mode inductors (700) includes a first inductor (710) and a second inductor (720), wherein the inductance values ​​of the first inductor (710) and the second inductor (720) are consistent.

7. The system according to claim 6, characterized in that, The inductance values ​​of the first inductor (710) and the second inductor (720) are set to 5 to 15 μH.

8. The system according to claim 1, characterized in that, The differential mode inductor (700) and the differential mode capacitor (800) are surface mount type.

9. The system according to claim 1, characterized in that, A transient voltage suppression unit (900) is connected between the positive power supply path (500) and the negative power supply path (600). The transient voltage suppression unit (900) is connected in parallel between the positive input terminal (100) and the negative input terminal (300) to absorb the surge voltage at the input terminal.

10. A motor controller, characterized in that, include: Main controller power module; A drive power module, which is connected to the main controller power module; as well as The low-voltage source electromagnetic compatibility system according to any one of claims 1 to 9 has its input terminal connected to the low-voltage battery of the electric vehicle and its output terminal connected to the input terminal of the main controller power module.

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