Method, circuit and system for suppressing electromagnetic noise of DC brush motor

Abstract

The embodiment of the invention provides a method, a circuit and a system for suppressing electromagnetic noise of a DC brush motor. The method comprises the following steps: configuring at least two filtering units with different frequency response characteristics; arranging at least two filtering units on a noise propagation path of the DC brush motor; noise components of different sub-frequency bands in the wide-spectrum noise generated by the direct-current brush motor are suppressed through at least two filtering units; wherein the synergistic effect of the at least two filtering units realizes suppression of electromagnetic noise in a preset full frequency band. The method is used for improving the denoising accuracy of the brush motor.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, and in particular to a method, circuit, and system for suppressing electromagnetic noise of a DC brushed motor. Background Technology

[0002] Brushed DC motors are widely used in the automotive industry, home appliances, industrial equipment, and automation control. During operation, brushed motors continuously generate broadband electromagnetic interference due to mechanical friction and arcing between the brushes and the commutator.

[0003] In related technologies, using a single capacitor filter to filter electromagnetic interference noise can only attenuate noise in a specific frequency band, resulting in low noise reduction accuracy. Therefore, how to suppress electromagnetic noise caused by brushed motors across the entire frequency band has become an urgent technical problem to be solved. Summary of the Invention

[0004] This application provides a method, circuit, and system for suppressing electromagnetic noise in a DC brushed motor, thereby achieving the technical effect of improving the noise reduction accuracy of the brushed motor.

[0005] In a first aspect, embodiments of this application provide a method for suppressing electromagnetic noise in a DC brushed motor, comprising:

[0006] Configure at least two filter units with different frequency response characteristics;

[0007] The at least two filter units are arranged in the noise propagation path of the DC brushed motor;

[0008] The at least two filtering units respectively suppress the noise components of different sub-frequency bands in the broadband noise generated by the DC brushed motor;

[0009] The synergistic effect of the at least two filtering units enables the suppression of electromagnetic noise within a preset full frequency band.

[0010] In one possible implementation, at least two filter units with different frequency response characteristics are provided, including:

[0011] At least one first-type filter unit is configured to suppress noise conducted through wires; and at least one second-type filter unit is configured to suppress noise radiated through space.

[0012] In one possible implementation, at least one type-two filter unit is configured to suppress noise radiated through space, including:

[0013] At least one differential mode suppression unit is configured to suppress noise generated between power lines; and at least one common mode suppression unit is configured to suppress noise generated between power lines and ground.

[0014] In one possible implementation, configuring at least one type-first filter unit to suppress noise conducted through the wire includes:

[0015] At least one microfarad-level multilayer ceramic capacitor is configured to suppress conducted emission noise in a first preset frequency band; and at least one nanofarad-level feedthrough capacitor is configured to suppress conducted emission noise in a second preset frequency band.

[0016] In one possible implementation, at least one type-two filter unit is configured to suppress noise radiated through space, including:

[0017] At least one magnetic bead is configured to absorb the energy of high-frequency noise current; and at least one nanofarad and / or picofarad multilayer ceramic capacitor is configured in conjunction with the magnetic bead to filter out noise within a third preset frequency band.

[0018] Secondly, embodiments of this application provide an electromagnetic noise suppression circuit for a DC brushed motor, disposed along the noise propagation path of the motor, the circuit comprising:

[0019] At least two filtering modules, which have different frequency response characteristics, are configured to suppress noise in different sub-frequency bands respectively, and suppress noise in a preset full frequency band through synergistic effect.

[0020] In one possible implementation, the at least two filtering modules include a module for suppressing conducted emissions and a module for suppressing radiated emissions;

[0021] The circuit also includes a grounding port for connecting the metal casing of the motor to a reference ground.

[0022] In one possible implementation, the at least two filtering modules include at least two of the following circuit structures:

[0023] a) Circuit structure including microfarad-level capacitors;

[0024] b) A circuit structure including nanofarad-level feedthrough capacitors connected to the ground port;

[0025] c) A circuit structure that includes a ferrite bead and a small-capacity capacitor connected in parallel;

[0026] d) Circuit structures that include differential-mode inductors and common-mode inductors.

[0027] In one possible implementation, the circuit includes the circuit structures a), b), c), and d).

[0028] The circuit has a symmetrical first branch and a second branch, which are respectively connected between the positive and negative terminals of the power supply and the motor.

[0029] The first coil of the common-mode inductor and the differential-mode inductor are connected in series in the first branch, and the second coil of the common-mode inductor is connected in series in the second branch;

[0030] The microfarad-level capacitor is connected between the first branch and the second branch.

[0031] The feedthrough capacitor is connected between the first branch and / or the second branch and the grounding port;

[0032] The circuit structure in which the magnetic bead and the small-capacity capacitor are connected in parallel is connected in series in the first branch and / or the second branch.

[0033] Thirdly, embodiments of this application provide a DC brushed motor system, including: a DC brushed motor, and an electromagnetic noise suppression circuit as described in the second aspect.

[0034] Fourthly, embodiments of this application provide a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, causes the processor to perform the following steps:

[0035] Obtain status information related to the noise of a DC brushed motor;

[0036] Based on the state information, control commands are generated to adjust the operating state of at least one filter module in the circuit as described in the second aspect.

[0037] The method, circuit, and system for suppressing electromagnetic noise of a brushed DC motor provided in this application solve the technical problem in related technologies where the frequency response curve is fixed, resulting in good suppression in one frequency band but poor suppression in other frequency bands. By setting multiple filter units, each with its own expertise, effective suppression of noise in different sub-frequency bands is achieved simultaneously, thereby suppressing electromagnetic noise across the entire frequency band and improving the accuracy of electromagnetic noise suppression for brushed DC motors. Attached Figure Description

[0038] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0039] Figure 1A flowchart illustrating the method for suppressing electromagnetic noise of a DC brushed motor provided in this application embodiment. Figure 1 ;

[0040] Figure 2 A flowchart illustrating the method for suppressing electromagnetic noise of a DC brushed motor provided in this application embodiment. Figure 2 ;

[0041] Figure 3 A schematic diagram of the electromagnetic noise suppression circuit for a DC brushed motor provided in the embodiments of this application. Figure 1 ;

[0042] Figure 4 A schematic diagram of the electromagnetic noise suppression circuit for a DC brushed motor provided in the embodiments of this application. Figure 2 ;

[0043] Figure 5 This is a schematic diagram of the structure of a DC brushed motor system provided in an embodiment of this application;

[0044] Figure 6 A schematic diagram of the structure of the device for suppressing electromagnetic noise of a DC brushed motor provided in the embodiments of this application;

[0045] Figure 7 This is a schematic diagram of the structure of a device for suppressing electromagnetic noise of a DC brushed motor provided in an embodiment of this application.

[0046] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0047] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0048] DC brushed motors are widely used in the automotive industry, home appliances, industrial equipment, and automation control fields due to their simple structure, low cost, and excellent speed regulation performance. For example, DC brushed motors are core power components in electric power steering systems of electric vehicles, cooling fan drives of hybrid vehicles, joint motors of industrial robots, propeller drives of drones, and compressors of household air conditioners.

[0049] However, during operation, these motors continuously generate broadband electromagnetic interference due to mechanical friction and arcing between the brushes and commutator, with noise frequencies covering an ultra-wide band from 0Hz to 6GHz. This noise not only propagates to other electronic devices through conduction paths (such as power lines), causing signal interference, but can also affect wireless communication systems (such as FM radio and GPS navigation) through spatial radiation. Particularly in automotive electronic systems, electromagnetic interference can lead to false triggering or malfunctions of onboard electronic control units, sensors, and communication modules, and in severe cases, even threaten driving safety. Furthermore, with increasingly stringent electromagnetic compatibility standards, products must pass rigorous electromagnetic interference testing before being released to the market. Existing simple filtering schemes are insufficient to meet the requirements for full-band noise suppression, resulting in extended product development cycles, high test failure rates, and directly impacting product competitiveness.

[0050] In related technologies, simple filter circuits are used to suppress noise in circuits. For example, simple filter circuits include π-type filters (composed of a capacitor-inductor-capacitor series) or single-capacitor filter circuits. These schemes attenuate noise in specific frequency bands by utilizing the high-frequency bypass effect of capacitors and the low-frequency impedance characteristics of inductors. However, their designs lack targeted analysis of the noise spectrum distribution, resulting in insufficient conducted emission suppression in the low-frequency range (e.g., 0-30MHz) and limited radiated emission control in the high-frequency range (e.g., above 108MHz).

[0051] The method, circuit, and system for suppressing electromagnetic noise of DC brushed motors provided in this application are intended to solve the aforementioned technical problems.

[0052] The technical solution of this application and how it solves the above-mentioned technical problems will be described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will be described below with reference to the accompanying drawings.

[0053] Figure 1 A flowchart illustrating the method for suppressing electromagnetic noise of a DC brushed motor provided in this application embodiment. Figure 1 ,like Figure 1 As shown, the method includes:

[0054] S101. Configure at least two filter units with different frequency response characteristics.

[0055] This application is applied to the electromagnetic noise suppression circuit of a DC brushed motor. It can be configured with at least two filter units with different frequency response characteristics and arranged on the power input path of the DC brushed motor to form a composite filter network.

[0056] For example, by analyzing the collected data on electromagnetic noise generated during the operation of a DC brushed motor, the inventors determined that the frequency range of the electromagnetic noise generated during the operation of the DC brushed motor is from 0Hz to 6GHz. Therefore, at least two filtering units can be configured to suppress electromagnetic noise across the entire frequency band from 0Hz to 6GHz.

[0057] The configuration includes at least one first filter unit among at least two filter units, used to suppress radiated noise in the 200MHz to 6GHz frequency band. The configuration also includes at least one second filter unit among at least two filter units, used to suppress radiated noise in the 0Hz to 200MHz frequency band.

[0058] S102. Arrange at least two filter units on the noise propagation path of the DC brushed motor.

[0059] For example, at least two filter units are arranged on the noise propagation path of the DC brushed motor. For instance, at least one first filter unit and at least one second filter unit are connected in series or in parallel on the power input path of the DC brushed motor to form a composite filter network.

[0060] S103. At least two filtering units are used to suppress noise components in different sub-frequency bands of the broadband noise generated by the DC brushed motor; wherein, the synergistic effect of at least two filtering units achieves the suppression of electromagnetic noise in the preset full frequency band.

[0061] For example, during the operation of a DC brushed motor, noise components in different sub-frequency bands of the broadband noise generated by the DC brushed motor can be suppressed by at least two filtering units.

[0062] For example, when electromagnetic noise reaches at least one first filter unit, the radiated noise in the 200MHz to 6GHz frequency band is suppressed through the suppression effect of at least one first filter unit. When electromagnetic noise reaches at least one second filter unit, the radiated noise in the 0Hz to 200MHz frequency band is suppressed through the suppression effect of at least one second filter unit. This achieves the synergistic filtering effect of at least two filter units, thereby suppressing electromagnetic noise within a preset full frequency band. The preset full frequency band refers to electromagnetic noise from 0Hz to 6GHz.

[0063] The method for suppressing electromagnetic noise of a brushed DC motor provided in this application solves the technical problem in related technologies where the frequency response curve is fixed, resulting in good suppression in one frequency band but poor suppression in other frequency bands. By configuring at least two filter units with different frequency response characteristics and making them work together, the method effectively suppresses noise in different sub-frequency bands simultaneously, thereby achieving full-band electromagnetic noise suppression and improving the accuracy of suppressing electromagnetic noise of brushed DC motors.

[0064] Figure 2 A flowchart illustrating the method for suppressing electromagnetic noise of a DC brushed motor provided in this application embodiment. Figure 2 ,like Figure 2 As shown, the above configuration of at least two filter units with different frequency response characteristics includes: configuring at least one first-type filter unit to suppress noise conducted through wires; and configuring at least one second-type filter unit to suppress noise radiated through space. The method includes:

[0065] S201. Configure at least one type-1 filter unit to suppress noise conducted through wires; and configure at least one type-2 filter unit to suppress noise radiated through space.

[0066] For example, at least one type-1 filter unit can be configured to suppress noise conducted through wires. At least one type-2 filter unit can be configured to suppress noise radiated through space.

[0067] Specifically, the above configuration of at least one type-two filter unit to suppress noise radiated through space includes:

[0068] At least one differential mode suppression unit is configured to suppress noise generated between power lines; and at least one common mode suppression unit is configured to suppress noise generated between power lines and ground.

[0069] For example, a differential mode suppression unit can be configured on the noise propagation path of a DC brushed motor, such as at the motor power input (positive terminal). The differential mode suppression unit includes at least one differential mode inductor, such as the differential mode inductor connected in series on the noise propagation path of the DC brushed motor, to suppress noise generated between power lines.

[0070] At least one common-mode suppression unit is configured in the noise propagation path of the DC brushed motor. The common-mode suppression unit includes at least one common-mode inductor for suppressing noise generated between the power line and ground.

[0071] For example, a first coil of a common-mode inductor is configured in the noise propagation path of a DC brushed motor, adjacent to the motor power input (positive terminal); and a second coil of the same common-mode inductor is configured in the noise propagation path of a DC brushed motor, adjacent to the motor power output (negative terminal).

[0072] The differential-mode inductor blocks noise entangled between the two wires, while the common-mode inductor blocks synchronized noise on both wires. The differential-mode and common-mode inductors work together to suppress radiated noise in the 200MHz to 6GHz frequency band.

[0073] The advantage of this configuration is that by specifically dividing the unit for suppressing radiated noise into differential-mode suppression units and common-mode suppression units, the differential-mode suppression unit is dedicated to increasing the impedance of the differential-mode current path, while the common-mode suppression unit is dedicated to canceling the magnetic field generated by the common-mode current. This systematically and comprehensively solves the problem of combined radiated noise.

[0074] The above configuration of at least one type-first filter unit to suppress noise conducted through wires includes:

[0075] At least one microfarad-level multilayer ceramic capacitor is configured to suppress conducted emission noise in a first preset frequency band; and at least one nanofarad-level feedthrough capacitor is configured to suppress conducted emission noise in a second preset frequency band.

[0076] For example, at least one microfarad-level multilayer ceramic capacitor can be connected in parallel along the noise propagation path of a DC brushed motor, such as between the positive and negative terminals of the motor drive circuit. This is used to suppress conducted emission noise within a first preset frequency band. For example, the first preset frequency band is low-frequency conducted emission noise in the 0Hz to 30Hz frequency range.

[0077] At least one nanofarad-sized feedthrough capacitor can be connected in parallel along the noise propagation path of a DC brushed motor, such as between the positive and negative terminals of the motor drive circuit, to suppress conducted emission noise within a second preset frequency band. For example, the second preset frequency band is the intermediate frequency conducted emission noise within the 30Hz to 108Hz range. It should be noted that one end of the nanofarad-sized feedthrough capacitor is connected to reference ground.

[0078] The advantage of this configuration is that by specifically defining the first type of filter unit used to suppress conducted noise as a combination of microfarad-level multilayer ceramic capacitors and nanofarad-level feedthrough capacitors, the very low impedance of the microfarad-level multilayer ceramic capacitors in the low-frequency range provides an extremely low-impedance local loop path for low-frequency conducted noise currents, thus preventing low-frequency noise from propagating deep into the power supply system. The nanofarad-level feedthrough capacitors efficiently guide mid-frequency noise from the motor drive circuit to the system reference ground, rather than allowing the noise to continue propagating along the power lines. The combined effect of the microfarad-level multilayer ceramic capacitors and the nanofarad-level feedthrough capacitors achieves precise, layered suppression of electromagnetic noise from low to mid-frequency.

[0079] The above configuration of at least one type-two filter unit to suppress noise radiated through space includes:

[0080] At least one ferrite bead is configured to absorb the energy of high-frequency noise current; and at least one nanofarad and / or picofarad multilayer ceramic capacitor is configured in conjunction with the ferrite bead to filter out noise within a third preset frequency band.

[0081] For example, at least one ferrite bead can be connected in series along the noise propagation path of a DC brushed motor, such as in the motor drive circuit, to absorb the energy of high-frequency noise current. The ferrite bead can absorb the energy of high-frequency noise and convert it into a small amount of heat that is dissipated. Simultaneously, at least one nanofarad and / or picofarad-level multilayer ceramic capacitor can be connected in parallel along the noise propagation path of the DC brushed motor, such as in the motor drive circuit. One end of the parallel multilayer ceramic capacitor is connected to a reference ground, and it works in conjunction with the ferrite bead to filter out noise within a third preset frequency band. The third preset frequency band is high-frequency radiated emission noise in the 108Hz to 6GHz frequency band.

[0082] The advantage of this configuration is that the ferrite bead exhibits high resistance at high frequencies, converting the electromagnetic energy of high-frequency noise current into heat and dissipating it. Simultaneously, the nanofarad or picofarad-level multilayer ceramic capacitor exhibits extremely low impedance at high frequencies. After the ferrite bead absorbs energy and increases impedance in the series path, the small-capacity multilayer ceramic capacitor, in parallel, provides a near-short-circuit ideal path to ground for the participating high-frequency noise. Together, the ferrite bead and the jointly connected small-capacity multilayer ceramic capacitor form a low-pass filter network with extremely strong attenuation effect on electromagnetic noise in a specific high-frequency range, thus completely bypassing any high-frequency components that leak through the filter, building upon the differential-mode suppression and common-mode suppression units.

[0083] S202. Arrange at least two filter units on the noise propagation path of the DC brushed motor.

[0084] S203. At least two filtering units are used to suppress noise components in different sub-frequency bands of the broadband noise generated by the DC brushed motor.

[0085] In some implementations, an adaptive control module, including a speed monitoring module and a dynamic switching control module, can be configured to dynamically adjust the filtering parameters based on the real-time speed of the DC brushed motor. This achieves dynamically optimal electromagnetic noise suppression.

[0086] For example, a speed monitoring module can acquire the motor's speed signal in real time. A dynamic switching control module can then control the combination of filtering components connected along the noise propagation path of the DC brushed motor based on the speed signal.

[0087] For example, Hall effect sensors or photoelectric encoders can be directly mounted on the motor shaft to generate pulse signals proportional to the rotational speed, thereby enabling real-time monitoring of the DC brushed motor's speed. The output of the speed monitoring module is then connected to the input of the dynamic switching control module.

[0088] Some filtering components, such as at least one nanofarad-level feedthrough capacitor for suppressing intermediate frequency (IF) noise, can have their input capacitance values ​​set to be switchable. For example, each nanofarad-level feedthrough capacitor for suppressing IF noise can be configured with multiple analog switches, with one end of the capacitor connected to the filtering node and the other end connected to each analog switch. By controlling the opening and closing states of the analog switches, capacitors with different capacitance values ​​can be connected and disconnected.

[0089] The dynamic switching control module can be a simple microcontroller that receives the speed signal from the speed monitoring module. Internally, it stores a mapping table of speed and optimal filtering parameters. This mapping table, established through prior testing and theoretical analysis, clarifies the optimal equivalent capacitance value that the filtering circuit should connect to achieve the best filtering effect in different speed ranges. The dynamic switching module queries the mapping table based on the current speed and generates a corresponding control signal to drive a multi-channel analog switch, thereby adding the corresponding capacitor or capacitor combination to the noise propagation path.

[0090] Figure 3 A schematic diagram of the electromagnetic noise suppression circuit for a DC brushed motor provided in the embodiments of this application. Figure 1 ,like Figure 3 As shown, the circuit is positioned along the noise propagation path of the motor, and the circuit includes:

[0091] At least two filtering modules, each with different frequency response characteristics, are configured to suppress noise in different sub-bands and suppress noise across a preset full frequency band through synergistic action.

[0092] For example, the electromagnetic noise suppression circuit, as a separate filtering module, is connected in series between the power output terminal of the motor driver and the motor body. This circuit is installed inside the motor housing, as close as possible to the motor's power terminals.

[0093] The circuit includes at least two core filtering modules, such as a first filtering module and a second filtering module. The first filtering module is primarily responsible for suppressing high-frequency radiated emission noise, with its frequency response centered above 200MHz. The second filtering module is primarily responsible for suppressing low-frequency conducted emissions and mid-frequency noise, with its frequency response covering 0Hz to 200MHz. These two modules work together as a whole to collaboratively suppress bidirectional broadband noise flowing from the motor to the power supply and from the power supply to the motor.

[0094] In this embodiment, the electromagnetic noise suppression circuit also includes a grounding port for connecting the metal casing of the motor to a reference ground.

[0095] Figure 4 A schematic diagram of the electromagnetic noise suppression circuit for a DC brushed motor provided in the embodiments of this application. Figure 2 ,like Figure 4 As shown, at least two filter modules include at least two of the following circuit structures:

[0096] a) Circuit structure including microfarad-level capacitors;

[0097] b) A circuit structure including nanofarad-level feedthrough capacitors connected to a ground port;

[0098] c) A circuit structure that includes a ferrite bead and a small-capacity capacitor connected in parallel;

[0099] d) Circuit structures that include differential-mode inductors and common-mode inductors.

[0100] Specifically, the electromagnetic noise suppression circuit has a symmetrical first branch and a second branch, which are respectively connected between the positive and negative terminals of the power supply and the motor.

[0101] The first coil of the common-mode inductor and the differential-mode inductor are connected in series in the first branch, and the second coil of the common-mode inductor is connected in series in the second branch;

[0102] A microfarad-level capacitor is connected between the first branch and the second branch.

[0103] The feedthrough capacitor is connected between the first branch and / or the second branch and the grounding port;

[0104] The circuit structure in which the ferrite bead and the small-capacity capacitor are connected in parallel is connected in series in the first branch and / or the second branch.

[0105] For example, such as Figure 4The first branch of the electromagnetic noise suppression circuit has a common-mode inductor 424 and a differential-mode inductor 423 connected in series, and the second branch has a common-mode inductor 425 connected in series.

[0106] The first end 418 of the first branch is connected to the positive drive terminal of the DC brushed motor, and the second end 414 of the first branch is connected to the positive terminal of the DC brushed motor; the first end 419 of the second branch is connected to the negative drive terminal of the DC brushed motor, and the second end 416 of the second branch is connected to the negative terminal of the DC brushed motor.

[0107] The first branch contains a first ferrite bead 407 connected in series. The first branch includes a first connection point 409, a second connection point 410, and a third connection point 411. The first connection point 409 is connected to the first terminal of the first capacitor (microfarad-level multilayer ceramic capacitor) 401. The second connection point 410 is connected to the first terminal of the second capacitor (nanofa-level feedthrough capacitor) 402. The third connection point 411 is connected to the first terminal of the third branch. The third branch includes a third capacitor (nanofa-level multilayer ceramic capacitor) 403 and a fourth capacitor (picofa-level multilayer ceramic capacitor) 404 connected in parallel. The second terminal 413 of the third branch is connected to the metal casing of the DC brushed motor. The second capacitor 402 is connected to the metal casing of the DC brushed motor via connection point 415.

[0108] The second branch contains a second magnetic bead 408 connected in series. The second branch includes a fourth connection point 420, a fifth connection point 421, and a sixth connection point 412. The fourth connection point 420 is connected to the second terminal of the first capacitor 401, the fifth connection point 421 is connected to the second terminal of the second capacitor 402, and the sixth connection point 412 is connected to the first terminal of the fourth branch. The fourth branch includes a fifth capacitor (nanofa-level multilayer ceramic capacitor) 405 and a sixth capacitor (picofa-level multilayer ceramic capacitor) 406 connected in parallel. The second terminal 417 of the fourth branch is connected to the metal casing of the DC brushed motor.

[0109] When a DC brushed motor is working, the electromagnetic noise it generates is transmitted to different electronic components of the electromagnetic noise suppression circuit. The electromagnetic noise in different frequency ranges is attenuated by the corresponding electronic components.

[0110] The differential-mode inductor 323 is used to suppress differential-mode noise emission in the range of 200 MHz to 6 GHz; the common-mode inductor is used to suppress common-mode noise emission in the range of 200 MHz to 6 GHz.

[0111] The first capacitor 401 is a microfarad-level multilayer ceramic capacitor used to filter electromagnetic noise in the range of 0 Hz to 30 MHz. The second capacitor 402 is a nanofarad-level feedthrough capacitor used to filter electromagnetic noise in the range of 30 MHz to 108 MHz. The third capacitor 403, the fourth capacitor 404, the fifth capacitor 405, the sixth capacitor 406, the first ferrite bead 407, and the second ferrite bead 408 are used to filter electromagnetic noise above 408 MHz. Among them, the third capacitor 403, the fourth capacitor 404, the fifth capacitor 405, and the sixth capacitor 406 are used to suppress electromagnetic noise above 108 MHz, while the first ferrite bead 407 and the second ferrite bead 408 are used to absorb the energy of electromagnetic noise above 108 MHz and convert it into a small amount of heat for dissipation. The third branch, the fourth branch, and the second capacitor 402 are connected to the metal casing of the brushed motor, and the metal casing is connected to the reference ground through a low-impedance path, providing a discharge path for electromagnetic noise, thereby achieving the noise reduction effect.

[0112] It should be noted that when laying out the printed circuit board for the electromagnetic noise suppression circuit of a DC brushed motor, the electronic components in the electromagnetic noise suppression circuit of the DC brushed motor, especially the first ferrite bead, the second ferrite bead, the nanofarad-level feedthrough capacitor, and the picofarad-level feedthrough capacitor, can be placed close to the power input to maximize the high-frequency suppression effect.

[0113] It should be noted that the method embodiments provided in this application can be applied to the circuit embodiments provided in this application.

[0114] Experimental data show that after connecting an electromagnetic noise suppression circuit in series in the drive circuit of a DC brushed motor, the electromagnetic noise in the entire frequency band from 0 Hz to 6 GHz is within the acceptable range during electromagnetic compatibility testing.

[0115] Figure 5 The schematic diagram of the DC brushed motor system provided in the embodiment of this application includes a DC brushed motor 501 and an electromagnetic noise suppression circuit 502.

[0116] For example, the electromagnetic noise suppression circuit 502 is disposed at the power input terminal of the DC brushed motor 501. The electromagnetic noise suppression circuit 502 has a symmetrical first branch and a second branch, which are respectively connected between the positive terminal of the power supply and the positive input terminal of the motor, and between the negative terminal of the power supply and the negative input terminal of the motor.

[0117] The electromagnetic noise suppression circuit 502 integrates a) a circuit structure containing microfarad-level capacitors; b) a circuit structure containing nanofarad-level feedthrough capacitors; c) a circuit structure containing a ferrite bead and a small-capacity capacitor in parallel; and d) a circuit structure containing differential-mode inductors and common-mode inductors.

[0118] Near the power input side, a 10µF microfarad-level multilayer ceramic capacitor is connected between the first and second branches. This capacitor is primarily used to provide a low-impedance discharge path for low-frequency conducted emission noise from 0Hz to 30MHz.

[0119] On the first branch, a 100nF nanofarad-level feedthrough capacitor is connected in series. The metal casing of the feedthrough capacitor is connected to the ground port in the circuit via a low-impedance path (this port is ultimately connected to the system reference ground, such as the PCB ground plane or the chassis). Similarly, an identical feedthrough capacitor is connected in series on the second branch and grounded. This pair of feedthrough capacitors is primarily used to suppress noise in the 30MHz to 108MHz frequency band.

[0120] Following the feedthrough capacitor, near the motor side, a combination consisting of a ferrite bead and a 100pF picofarad-level multilayer ceramic capacitor connected in parallel is connected in series in the first branch. Similarly, a combination consisting of a ferrite bead and a 100pF picofarad-level multilayer ceramic capacitor connected in parallel is connected in series in the second branch. The impedance of the ferrite bead is preferably 100 ohms at 100MHz. This combined structure absorbs high-frequency noise energy through the ferrite bead and provides high-frequency bypass through the small-capacity multilayer ceramic capacitor, together suppressing high-frequency radiated emission noise above 108MHz.

[0121] At the very end of the circuit on the motor side, an integrated magnetic core is positioned, on which coils constituting the differential-mode inductor and the common-mode inductor are wound. The first coil of the common-mode inductor and the differential-mode inductor are connected in series in the first branch. The second coil of the common-mode inductor is connected in series in the second branch. This inductor structure is primarily used to suppress common-mode and differential-mode radiated noise in the 200MHz to 6GHz frequency band.

[0122] Figure 6 This is a schematic diagram of the device for suppressing electromagnetic noise of a DC brushed motor provided in an embodiment of this application, as shown below. Figure 6 As shown, the device 60 for suppressing electromagnetic noise of a DC brushed motor provided in this embodiment includes:

[0123] Configuration module 601 is used to configure at least two filter units with different frequency response characteristics;

[0124] Arrangement module 602 is used to arrange at least two filter units on the noise propagation path of the DC brushed motor;

[0125] Suppression module 603 is used to suppress noise components of different sub-frequency bands in the broadband noise generated by a DC brushed motor through at least two filtering units;

[0126] The coordinated action of at least two filtering units enables the suppression of electromagnetic noise across the preset full frequency band.

[0127] In one possible implementation, configuration module 601 is further used for:

[0128] At least one first-type filter unit is configured to suppress noise conducted through wires; and at least one second-type filter unit is configured to suppress noise radiated through space.

[0129] In one possible implementation, configuration module 601 is further used for:

[0130] At least one differential mode suppression unit is configured to suppress noise generated between power lines; and at least one common mode suppression unit is configured to suppress noise generated between power lines and ground.

[0131] In one possible implementation, configuration module 601 is further used for:

[0132] At least one microfarad-level multilayer ceramic capacitor is configured to suppress conducted emission noise in a first preset frequency band; and at least one nanofarad-level feedthrough capacitor is configured to suppress conducted emission noise in a second preset frequency band.

[0133] In one possible implementation, configuration module 601 is further used for:

[0134] At least one ferrite bead is configured to absorb the energy of high-frequency noise current; and at least one nanofarad and / or picofarad multilayer ceramic capacitor is configured in conjunction with the ferrite bead to filter out noise within a third preset frequency band.

[0135] The device for suppressing electromagnetic noise of a DC brushed motor provided in this embodiment can perform the method provided in the above-described method embodiment. Its implementation principle and technical effect are similar, and will not be described in detail here.

[0136] Figure 7 This is a schematic diagram of the structure of a device for suppressing electromagnetic noise of a DC brushed motor, provided in an embodiment of this application. Figure 7 As shown, the device 760 for suppressing electromagnetic noise of a DC brushed motor provided in this embodiment includes at least one processor 701 and a memory 702. Optionally, the device 70 for suppressing electromagnetic noise of a DC brushed motor further includes a communication component 703. The processor 701, memory 702, and communication component 703 are connected via a bus.

[0137] In a specific implementation, at least one processor 701 executes computer execution instructions stored in memory 702, causing at least one processor 701 to perform the above-described method.

[0138] The specific implementation process of processor 701 can be found in the above method embodiments, and its implementation principle and technical effect are similar. It will not be repeated here.

[0139] In the above embodiments, it should be understood that the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in this invention can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor.

[0140] The memory may include random access memory (RAM) and may also include non-volatile memory (NVM), such as at least one disk storage device.

[0141] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of illustration, the buses shown in the accompanying drawings are not limited to a single bus or a single type of bus.

[0142] This application also provides a computer program product having a computer program stored thereon, which, when executed by a processor, causes the processor to perform the following steps:

[0143] Obtain status information related to the noise of a DC brushed motor;

[0144] Based on the state information, control commands are generated to adjust the operating state of at least one filtering module in the circuit embodiment.

[0145] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the above-described method.

[0146] The aforementioned readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. The readable storage medium can be any available medium accessible to a general-purpose or special-purpose computer.

[0147] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can reside in an Application Specific Integrated Circuit (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components in the device.

[0148] The division of units is merely a logical functional division; in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0149] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0150] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0151] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0152] Those skilled in the art will understand that all or part of the steps of the above-described method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0153] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A method for suppressing electromagnetic noise in a DC brushed motor, characterized in that, include: Configure at least two filter units with different frequency response characteristics; The at least two filter units are arranged in the noise propagation path of the DC brushed motor; The at least two filtering units respectively suppress the noise components of different sub-frequency bands in the broadband noise generated by the DC brushed motor; The synergistic effect of the at least two filtering units enables the suppression of electromagnetic noise within a preset full frequency band.

2. The method according to claim 1, characterized in that, Configure at least two filter units with different frequency response characteristics, including: At least one first-type filter unit is configured to suppress noise conducted through wires; and at least one second-type filter unit is configured to suppress noise radiated through space.

3. The method according to claim 2, characterized in that, Configure at least one type-two filter unit to suppress noise radiated through space, including: At least one differential mode suppression unit is configured to suppress noise generated between power lines; and at least one common mode suppression unit is configured to suppress noise generated between power lines and ground.

4. The method according to claim 2, characterized in that, Configure at least one type-first filter unit to suppress noise conducted through wires, including: At least one microfarad-level multilayer ceramic capacitor is configured to suppress conducted emission noise in a first preset frequency band; and at least one nanofarad-level feedthrough capacitor is configured to suppress conducted emission noise in a second preset frequency band.

5. The method according to claim 3, characterized in that, Configure at least one type-two filter unit to suppress noise radiated through space, including: At least one magnetic bead is configured to absorb the energy of high-frequency noise current; and at least one nanofarad and / or picofarad multilayer ceramic capacitor is configured in conjunction with the magnetic bead to filter out noise within a third preset frequency band.

6. An electromagnetic noise suppression circuit for a DC brushed motor, characterized in that, The circuit, positioned along the noise propagation path of the motor, includes: At least two filtering modules, which have different frequency response characteristics, are configured to suppress noise in different sub-frequency bands respectively, and suppress noise in a preset full frequency band through synergistic effect.

7. The circuit according to claim 6, characterized in that, The at least two filtering modules include a module for suppressing conducted emissions and a module for suppressing radiated emissions; The circuit also includes a grounding port for connecting the metal casing of the motor to a reference ground.

8. The circuit according to claim 7, characterized in that, The at least two filtering modules include at least two of the following circuit structures: a) Circuit structure including microfarad-level capacitors; b) A circuit structure including nanofarad-level feedthrough capacitors connected to the ground port; c) A circuit structure that includes a ferrite bead and a small-capacity capacitor connected in parallel; d) Circuit structures that include differential-mode inductors and common-mode inductors.

9. The circuit according to claim 8, characterized in that, The circuit includes circuit structures a), b), c), and d). The circuit has a symmetrical first branch and a second branch, which are respectively connected between the positive and negative terminals of the power supply and the motor. The first coil of the common-mode inductor and the differential-mode inductor are connected in series in the first branch, and the second coil of the common-mode inductor is connected in series in the second branch; The microfarad-level capacitor is connected between the first branch and the second branch. The feedthrough capacitor is connected between the first branch and / or the second branch and the grounding port; The circuit structure in which the magnetic bead and the small-capacity capacitor are connected in parallel is connected in series in the first branch and / or the second branch.

10. A DC brushed motor system, characterized in that, include: A DC brushed motor, and an electromagnetic noise suppression circuit as described in any one of claims 6-9.

11. A computer-readable storage medium, characterized in that, It stores a computer program that, when executed by a processor, causes the processor to perform the following steps: Obtain status information related to the noise of a DC brushed motor; Based on the state information, control commands are generated to adjust the operating state of at least one filter module in the circuit as described in any one of claims 6 to 9.

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