An electromagnetic compatibility filter structure and a motor controller

Abstract

This application relates to an electromagnetic compatibility (EMC) filtering structure and a motor controller, belonging to the field of automotive electronics technology. The EMC filtering structure includes a transient pulse suppression module, a common-mode inductor filtering module, and a CLCLC filtering module. The transient pulse suppression module is connected to the output terminal of the power supply for quickly clamping surge voltages. A grounded metal shield is connected between the transient pulse suppression module and the input terminal of the power supply. The common-mode inductor filtering module is connected to the output terminal of the transient pulse suppression module. The CLCLC filtering module is connected to the output terminal of the common-mode inductor filtering module and includes a first capacitor filter component, a first inductor, a second capacitor filter component, a second inductor, and a third capacitor filter component connected in sequence. The first and third capacitor filter components have the same capacitance value; the capacitance value of the second capacitor filter component is different from that of the first and third capacitor filter components. This application can effectively suppress broadband interference in a 24V system.

Description

Technical Field

[0001] This application relates to the field of automotive electronics technology, and in particular to an electromagnetic compatibility filter structure and a motor controller. Background Technology

[0002] With the rapid development of new energy vehicle technology, in order to improve charging efficiency and reduce the weight of vehicle wiring harnesses and energy loss, automotive electrical architecture is migrating from the traditional 400V platform to 800V or even higher voltage platforms. The 800V high-voltage platform brings significant performance advantages, but it also poses unprecedented challenges to the vehicle's electromagnetic compatibility (EMC).

[0003] Currently, 800V platform electronic control systems generally use 24V low-voltage power supply systems to provide power to key components such as motor controllers and ECUs. In terms of electromagnetic compatibility and interference immunity, due to the more complex operating environment of 800V platform electronic control vehicles, the power supply system is often subject to voltage fluctuations caused by motor start-stop and large load switching, as well as high-frequency noise interference generated by PWM speed regulation and relay switching.

[0004] These interferences can cause motor controller malfunctions, signal distortion, and even damage to electronic components, affecting the reliability and safety of the entire vehicle. Conversely, the motor controller also needs to effectively reduce its switching noise through the power line (conduction) and space (radiation) via a 24V low-voltage electromagnetic compatibility filtering system to avoid interfering with other onboard electronic devices and ensure the vehicle's EMC compliance and stable operation.

[0005] For the electronic control of the 800V platform, the π-type filter circuit of the low-voltage filter component in general civilian vehicles, even if the withstand voltage of its components is increased, still has insufficient optimization of its inductance parameters, and there is still room for improvement in terms of wideband interference suppression and transient response.

[0006] Therefore, there is an urgent need for a filtering scheme that can effectively suppress broadband interference in 24V systems. Utility Model Content

[0007] The purpose of this invention is to overcome the above-mentioned defects of the prior art and provide an electromagnetic compatibility filtering structure and motor controller, which can effectively suppress broadband interference of 24V system through a multi-level, cooperative composite filtering and protection system.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] Firstly, the electromagnetic compatibility filtering structure provided in this application adopts the following technical solution:

[0010] An electromagnetic compatibility filter structure, comprising:

[0011] Transient pulse suppression module, which is connected to the output of the power supply, is used to quickly clamp surge voltage;

[0012] A common-mode inductor filter module is connected to the output terminal of the transient pulse suppression module;

[0013] The CLCLC filter module is connected to the output terminal of the common mode inductor filter module, and includes a first capacitor filter component, a first inductor, a second capacitor filter component, a second inductor, and a third capacitor filter component connected in sequence.

[0014] The first capacitor filter component and the third capacitor filter component have the same capacitance value; the capacitance value of the second capacitor filter component is set differently from that of the first capacitor filter component and the third capacitor filter component.

[0015] Furthermore, the first capacitor filter assembly, the second capacitor filter group, and the third capacitor filter assembly each include multiple capacitors connected in parallel.

[0016] Furthermore, the capacitance parameters of the first capacitor and the third capacitor filter assembly include 4.7μF, 1μF, 100nF, 10nF and 1nF, and the capacitance parameters of the second capacitor filter assembly include 4.7μF, 100nF and 1nF.

[0017] Furthermore, the first inductor and the second inductor have the same inductance value.

[0018] Furthermore, a grounded metal shielding mesh is connected between the transient pulse suppression module and the input terminal of the power supply, and the metal shielding mesh covers the output terminal of the power supply and the input terminal of the transient pulse suppression module.

[0019] Furthermore, the metal shielding mesh includes an aluminum foil layer and a woven layer covering the aluminum foil layer.

[0020] Furthermore, the common-mode inductor filter module is configured as a surface-mount type.

[0021] Secondly, this application provides a motor controller that includes the aforementioned electromagnetic compatibility filtering structure.

[0022] In summary, this application includes at least one of the following beneficial technical effects:

[0023] 1. By integrating four protection measures—shielding, transient suppression, common-mode filtering, and differential-mode filtering—a three-dimensional EMC solution from the physical layer to the circuit layer is formed, which can systematically cope with various electromagnetic interferences such as conducted, radiated, and transient interferences.

[0024] 2. The CLCLC filter module, through a "symmetrical inductor, asymmetrical capacitor" design combined with multi-capacitor parallel technology, achieves an extremely wide effective filtering bandwidth and excellent noise attenuation depth, while effectively avoiding the anti-resonance problem of traditional filters. The symmetrical inductor design ensures stable filter operation and avoids internal oscillations. The multi-stage filtering design also improves system reliability, making it particularly suitable for long-term stable operation under complex automotive conditions. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the electromagnetic compatibility filtering structure in this application. Detailed Implementation

[0027] The technical solution of this application will now be clearly and completely described with reference to the accompanying drawings. The following embodiments are exemplary and are only used to explain this application, and should not be construed as limiting this application. In the following description, the same reference numerals are used to denote the same or equivalent elements, and repeated descriptions are omitted.

[0028] In the description of this application, it should be understood that the terms "upper", "lower", "inner", "outer", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this application and to simplify the description, and are not intended to indicate or imply that the equipment or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0029] Furthermore, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0030] It should also be further understood that the term “and / or” as used in this application refers to any combination of one or more of the listed items, and all possible combinations thereof.

[0031] An electromagnetic compatibility filter structure, referring to Figure 1 It includes a transient pulse suppression module, a common-mode inductor filter module, and a CLCLC filter module connected in sequence.

[0032] The transient pulse suppression module is connected to the output of the power supply and is used to quickly clamp surge voltages (such as ESD and load dump) to protect the common mode inductor filter module and CLCLC filter module at the back of the filter structure, ensuring equipment reliability and EMC compliance.

[0033] Specifically, the transient pulse suppression module includes a transient voltage suppressor diode (TVS). When a high-energy transient pulse (such as a load dump pulse with a voltage of hundreds of volts) occurs in the filter structure, the PN junction of the TVS diode rapidly undergoes avalanche breakdown. The TVS diode enters the avalanche breakdown state, and its impedance instantly drops to an extremely low level (ohm level) to form a low-impedance bypass path. Current is released through the formed bypass path, clamping the voltage across the TVS diode to a safe level. After the transient pulse passes and the line voltage returns to normal, the TVS diode automatically returns from the avalanche breakdown state to the high-impedance state, waiting for the next overvoltage event.

[0034] For example, for the pulse and load dump test requirements in the ISO16750-2 standard, the parameters of the transient voltage suppressor diode are selected as follows: maximum power handling capacity is set to 6600W, using DO-218AB package, reverse cutoff voltage is 36V, avalanche breakdown voltage is 40V, and clamping voltage is 58.1V.

[0035] This selection can reliably operate under transient overvoltage conditions such as load dumping and limit the voltage within a safe range.

[0036] Furthermore, referring to Figure 1 A grounded metal shield is connected between the transient pulse suppression module and the power supply input terminal. The metal shield covers the power supply output terminal and the transient pulse suppression module input terminal.

[0037] When the current transmitted inside the power supply harness contains high-frequency noise components, these changing currents radiate electromagnetic fields outward. The metal shielding layer, as a good conductor, induces eddy currents within it. The magnetic field generated by these eddy currents is opposite in direction to the original noise magnetic field, thus canceling out most of the radiated electromagnetic energy and preventing the power supply harness from becoming a "transmitting antenna".

[0038] Meanwhile, when an external electromagnetic field (such as mobile phone signal or high-voltage line radiation) is present, this electromagnetic field will induce a current in the shielding layer. The grounded metal shielding mesh provides a low-impedance discharge path for the induced high-frequency noise current, thereby blocking external electromagnetic interference, improving the system's immunity, ensuring accurate and reliable test results, and meeting the requirements of standards such as CISPR25.

[0039] For example, the metal shielding mesh includes an aluminum foil layer and a woven layer covering the aluminum foil layer.

[0040] This is a grounded metal shielding mesh, with an aluminum foil layer as the inner layer and a braided layer as the outer layer. The aluminum foil layer reflects and absorbs high-frequency electromagnetic waves to effectively suppress high-frequency noise and crosstalk, while the braided layer provides a thicker conductive material cross-section to protect the aluminum foil layer and shield low-frequency electromagnetic waves to handle external electromagnetic interference.

[0041] Furthermore, the common-mode inductor filter module is connected to the output of the transient pulse suppression module. The common-mode inductor filter module is used to create a high impedance for common-mode noise currents (such as PWM switching interference) through the symmetrical windings. It suppresses common-mode noise currents from being conducted to the subsequent CLCLC filter module to improve EMC performance. Simultaneously, the common-mode inductor filter module blocks the leakage of internal switching common-mode noise, ensuring signal integrity.

[0042] Specifically, common-mode noise current is a current flowing in the same direction on both the positive and negative terminals. These two currents, flowing in the same direction, generate magnetic flux in the magnetic core that is superimposed, inducing a strong magnetic field within the core. This causes the coil to exhibit a very high inductance to the common-mode current, i.e., high impedance. According to the impedance formula Z = 2πfL, the higher the frequency f, the greater the impedance Z.

[0043] For example, the common-mode inductor filter module adopts a surface-mount common-mode inductor structure, and the parameters of the common-mode inductor filter module are configured as follows:

[0044] 1) The common-mode impedance should not be less than 100Ω in the 100MHz-300MHz frequency band to effectively suppress the propagation of common-mode noise.

[0045] 2) The rated operating current is 3A, suitable for the power level of typical electronic control systems.

[0046] 3) The maximum withstand voltage is 125VDC, and the insulation resistance is not less than 100MΩ, ensuring reliable isolation and safe operation even under high voltage differential and harsh environments.

[0047] Furthermore, referring to Figure 1 The CLCLC filter module is connected to the output of the common-mode inductor filter module. It includes a first capacitor filter component, a first inductor, a second capacitor filter component, a second inductor, and a third capacitor filter component connected in sequence to form a fifth-order CLCLC topology.

[0048] The first capacitor filter component and the third capacitor filter component have the same capacitance value; the capacitance value of the second capacitor filter component is set differently from that of the first capacitor filter component and the third capacitor filter component.

[0049] As a low-pass filter, the CLCLC filter module combines capacitors to present low impedance (bypass function) for high-frequency signals and inductors to present high impedance (choke function) for high-frequency signals to efficiently remove wideband power supply noise.

[0050] Specifically, the noise signal enters the CLCLC module from the output of the common-mode inductor. First, the first capacitor filter bypasses a portion of the high-frequency noise to ground. Then, after passing through the choked first inductor, the amplitude of the remaining noise is attenuated. Next, the intermediate second capacitor filter performs another high-frequency bypass. Subsequently, the second inductor further chokes and attenuates the noise. Finally, the third capacitor filter performs the final bypass filtering.

[0051] Compared to traditional single-stage filtering solutions, the CLCLC filter module offers superior dynamic response characteristics while maintaining a compact size. It can quickly smooth voltage fluctuations caused by sudden load changes, ensuring the stability of control signals. The fifth-order CLCLC topology of the CLCLC filter module enhances system reliability and is particularly suitable for long-term stable operation under complex electrical control conditions, providing a highly efficient and reliable low-voltage power supply purification solution for motor controllers.

[0052] Furthermore, the first and second inductors have the same inductance value to ensure the phase balance and magnetic field symmetry of the filter network. This ensures the phase balance and impedance matching within the filter network, avoiding internal oscillations and reflections caused by inductance mismatch, which is the basis for the stable operation of the entire filter.

[0053] In a specific embodiment, the inductance values ​​of the first inductor and the second inductor include 10μH, 22μH, or 33μH. For example, the inductance values ​​of both the first inductor and the second inductor are set to 22μH. It should be noted that the inductance values ​​of the first inductor and the second inductor in this application can remain the same. This embodiment does not specifically limit the inductance values ​​of the first inductor and the second inductor; the inductance values ​​of the first inductor and the second inductor can be adaptively adjusted according to actual conditions.

[0054] Based on this, the first capacitor filter component and the third capacitor filter component have the same capacitance value; the capacitance value of the second capacitor filter component is set differently from that of the first capacitor filter component and the third capacitor filter component.

[0055] The first and third capacitor filter components located at the beginning and end of the CLCLC filter module have basically the same capacitance value, while the second capacitor filter component located in the middle uses a different capacitance value than the first and third capacitor filter components.

[0056] The symmetry between the first and second inductors, and the symmetry between the first and third capacitor filter components, together lay the foundation for stable system operation and effectively suppress loop oscillations. The capacitance value of the second capacitor filter component, in conjunction with the first and third capacitor filter components, further narrows the distribution range of the anti-resonance peak, thereby achieving better out-of-band attenuation characteristics and reliability while widening the frequency band.

[0057] Furthermore, the first, second, and third capacitor filter components each include multiple capacitors connected in parallel. This combination of multiple capacitors in parallel expands the effective operating frequency band of the CLCLC filter module.

[0058] For example, the capacitance parameters of the first capacitor and the third capacitor filter assembly include 4.7μF, 1μF, 100nF, 10nF and 1nF, and the capacitance parameters of the second capacitor filter assembly include 4.7μF, 100nF and 1nF.

[0059] Example 2:

[0060] The difference between this embodiment 2 and embodiment 1 is that a motor controller is also disclosed, which includes the electromagnetic compatibility filtering structure of embodiment 1.

[0061] 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 covered within the scope of protection of this application.

Claims

1. An electromagnetic compatibility filtering structure, characterized in that, The electromagnetic compatibility filter structure comprises: a transient pulse suppression module connected to an output end of a power supply for quickly clamping a surge voltage; a common mode inductance filter module connected to an output end of the transient pulse suppression module; a CLCLC filter module connected to an output end of the common mode inductance filter module, comprising a first capacitor filter assembly, a first inductor, a second capacitor filter assembly, a second inductor and a third capacitor filter assembly connected in sequence; wherein the first capacitor filter assembly and the third capacitor filter assembly have the same capacitance value, and the capacitance value of the second capacitor filter assembly is different from that of the first capacitor filter assembly and the third capacitor filter assembly.

2. The electromagnetic compatibility filter structure of claim 1, wherein, The first capacitor filter assembly, the second capacitor filter assembly and the third capacitor filter assembly each comprise a plurality of capacitors arranged in parallel.

3. An electromagnetic compatibility filter structure according to claim 2, characterised in that, The parameters of the capacitors of the first capacitor filter assembly and the third capacitor filter assembly include 4.7 μF, 1 μF, 100 nF, 10 nF and 1 nF, and the parameters of the capacitors of the second capacitor filter assembly include 4.7 μF, 100 nF and 1 nF.

4. The electromagnetic compatibility filter structure of claim 1, wherein, The first inductor and the second inductor have the same inductance value.

5. The electromagnetic compatibility filter structure of claim 1, wherein, A grounded metal shielding net is connected between the transient pulse suppression module and an input end of the power supply, and the metal shielding net covers the output end of the power supply and the input end of the transient pulse suppression module.

6. An electromagnetic compatibility filter structure according to claim 5, characterised in that, The metal shielding net comprises an aluminum foil layer and a braided layer covering the aluminum foil layer.

7. The electromagnetic compatibility filter structure of claim 3, wherein, The common mode inductance filter module is in a patch type.

8. An electric machine controller characterized by The electromagnetic compatibility filter structure comprises any one of claims 1-7. The electromagnetic compatibility filter structure comprises any one of claims 1-7.

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