CN218940946U

CN218940946U - Circuit for inhibiting electromagnetic interference of direct current motor

Info

Publication number: CN218940946U
Application number: CN202223112865.6U
Authority: CN
Inventors: 张强; 卢坤; 潘杰
Original assignee: Shenzhen Guoke Yidao Technology Co ltd
Current assignee: Shenzhen Guoke Yidao Technology Co ltd
Priority date: 2022-11-21
Filing date: 2022-11-21
Publication date: 2023-04-28
Anticipated expiration: 2032-11-21

Abstract

The utility model provides a circuit for inhibiting electromagnetic interference of a direct current motor, and belongs to the technical field of electromagnetic compatibility. The circuit for inhibiting electromagnetic interference of the direct current motor comprises a filtering module: the device is arranged at the output end of the input power supply and is used for filtering common mode interference signals and differential mode interference signals; and an absorption module: the filter module is arranged between the filter module and the direct current motor and is used for absorbing high-voltage pulses generated during the working of the direct current motor, wherein functional elements of the filter module and the absorption module are patch elements. The beneficial effects of the utility model are as follows: all the elements are patch devices, so that the filtering performance is improved, the patch devices are convenient to install in products with limited space, and the utilization rate of the product space is improved.

Description

Circuit for inhibiting electromagnetic interference of direct current motor

Technical Field

The utility model relates to the technical field of electromagnetic compatibility, in particular to a circuit for inhibiting electromagnetic interference of a direct current motor.

Background

At present, an electromagnetic protection circuit of a direct current motor generally adopts a filter circuit formed by differential mode inductance and Y capacitance to protect electromagnetic interference, and as the differential mode inductance and the Y capacitance are plug-in components, excessively high equivalent impedance and equivalent inductance exist on a too long pin under high-frequency interference, and the filter performance of the circuit is seriously affected; because of the large volume of the plug-in components, many small motors cannot be internally provided with the filter circuit for protection.

Disclosure of Invention

In order to solve the problems of poor filtering performance and large occupied volume of a circuit in the prior art, the utility model provides the circuit for inhibiting the electromagnetic interference of the direct current motor, which avoids overlong element pins, does not generate excessive equivalent impedance and equivalent inductance under high-frequency interference, and improves the filtering performance of the circuit.

The utility model relates to a circuit for inhibiting electromagnetic interference of a direct current motor, which comprises a filtering module: the device is arranged at the output end of the input power supply and is used for filtering common mode interference signals and differential mode interference signals; and an absorption module: the device is arranged between the filtering module and the direct current motor and is used for absorbing high-voltage pulses generated during the working of the direct current motor, wherein the filtering module and the absorbing module are patch elements.

According to a further improvement of the utility model, the absorption module comprises a bidirectional TVS tube or a piezoresistor, and the bidirectional TVS tube or the piezoresistor is connected with the direct current motor in parallel.

According to the utility model, the absorption module is a bidirectional TVS tube D1, one end of the bidirectional TVS tube D1 is connected with the positive electrode of the direct current motor, and the other end of the bidirectional TVS tube D1 is connected with the negative electrode of the direct current motor.

The utility model is further improved, the filtering module comprises a patch BDL filter U1, a power pin 1 of the patch BDL filter U1 is connected with the anode of an input power supply, a power pin 2 is connected with the cathode of the input power supply, and a first grounding pin 3 and a second grounding pin are respectively grounded.

The utility model further improves, the filtering module comprises a common mode interference absorbing unit and a differential mode interference absorbing unit,

the common-mode interference absorbing unit comprises a first patch Y capacitor C1 and a second patch Y capacitor C2, wherein one end of the first patch Y capacitor C1 is connected with the positive electrode of an input power supply, and the other end of the first patch Y capacitor C1 is connected with the ground of the power supply; one end of the second patch Y capacitor C2 is connected with the negative electrode of the input power supply, and the other end of the second patch Y capacitor C is connected with the power supply ground.

The utility model is further improved, the differential mode interference absorbing unit comprises a first magnetic bead L1 and a second magnetic bead L2, the first magnetic bead L1 and the first patch Y capacitor C1 form a first LC filter for filtering the positive electrode of a power supply, and the second magnetic bead L2 and the second patch Y capacitor C2 form a second LC filter for filtering the negative electrode of the power supply.

According to the utility model, the filter module further comprises a patch BDL filter U1 arranged between the input power supply output end and the input ends of the common mode interference absorbing unit and the differential mode interference absorbing unit, a power supply pin 1 of the patch BDL filter U1 is connected with the positive electrode of an input power supply, a power supply pin 2 is connected with the negative electrode of the input power supply, and the first grounding pin 3 and the second grounding pin are respectively grounded.

Compared with the prior art, the utility model has the beneficial effects that:

1. all elements in the filtering module and the absorbing module are patch devices, so that the patch device is small in size, simple in packaging and convenient to install in a product with limited space, and the utilization rate of the product space is improved;

2. all elements are patch devices, and can be made into a filter circuit board, so that the filter circuit board is convenient to install and easy to maintain;

3. all the elements are patch devices, and a universal filter circuit board corresponds to different direct current motors, so that the filter requirements can be met only by replacing parameters of the corresponding elements, and the filter debugging is convenient;

4. all the elements are patch devices, so that overlong element pins are avoided, excessive equivalent impedance and equivalent inductance cannot be generated under high-frequency interference, and the filtering performance of the circuit is improved.

Drawings

For a clearer description of the present application or of the solutions of the prior art, a brief introduction will be given below to the drawings used in the description of the embodiments or of the prior art, it being apparent that the drawings in the description below are some embodiments of the present application, from which other drawings can be obtained, without the inventive effort for a person skilled in the art.

FIG. 1 is a block diagram of a circuit configuration of the present utility model;

fig. 2 is a schematic circuit diagram of an embodiment of the present utility model.

Detailed Description

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the description of the applications herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having" and any variations thereof in the description and claims of the present application and in the description of the figures above are intended to cover non-exclusive inclusions. The terms first, second and the like in the description and in the claims or in the above-described figures, are used for distinguishing between different objects and not necessarily for describing a sequential or chronological order.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.

In order to better understand the technical solutions of the present application, the following description will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the accompanying drawings.

As shown in fig. 1, the circuit for suppressing electromagnetic interference of a dc motor according to the present utility model is mainly used for suppressing interference signals generated when the dc motor (also called an electric motor, a dc motor, or simply referred to as a motor) is in operation. The circuit for inhibiting the electromagnetic interference of the direct current motor comprises a filtering module, a first filtering module and a second filtering module, wherein the filtering module is arranged at the output end of an input power supply and is used for filtering common-mode interference signals and differential-mode interference signals; the absorption module is arranged between the filtering module and the direct current motor and is used for absorbing high-voltage pulses generated during the working of the direct current motor.

In fig. 1, the solid arrow direction is the current signal flow direction, and the broken arrow direction is the disturbance signal flow direction of the direct current motor. The method comprises the steps that an interference signal generated when a direct current motor works firstly passes through an absorption module, and the absorption module absorbs high-voltage pulses generated when the direct current motor works; and then the interference signals pass through a filtering module, the common mode interference signals and the differential mode interference signals are filtered by the filtering module, the interference signals are prevented from radiating outwards through a power line, and the electromagnetic compatibility of the direct current motor is improved.

The filter module and the absorption module are patch elements, so that overlong element pins are avoided, the patch elements cannot generate excessively high equivalent impedance and equivalent inductance under high-frequency interference, and the filter performance of the circuit is improved. In addition, the circuit functional elements are all set to be patch elements, the patch elements are small in size, simple in packaging and convenient to install in products with limited space, and the utilization rate of the product space is improved.

As shown in fig. 2, as an embodiment of the present utility model, the absorption module of this example preferably employs a bi-directional TVS tube D1, one end of the bi-directional TVS tube D1 is connected to the positive electrode of the dc motor, and the other end of the bi-directional TVS tube D1 is connected to the negative electrode of the dc motor. The bidirectional TVS tube D1 can absorb high-voltage surge and spark voltage generated when the direct-current motor works, and the influence of pulse peak voltage on a front-stage circuit is avoided.

The bidirectional TVS tube D1 of this example may be replaced with a varistor, which can achieve the same effect, but the service life of the varistor is limited, which affects the reliability of the entire circuit.

The filtering module of this example includes paster BDL wave filter U1, the positive pole of input power is received to power pin 1 of paster BDL wave filter U1, and the negative pole of input power is received to power pin 2, and first ground pin 3 and second ground pin ground respectively. The patch BDL filter U1 has excellent differential mode/common mode noise suppression effect, reduces the noise of the system and improves the anti-interference capability.

Preferably, the filtering module of this embodiment is further provided with a common mode interference absorbing unit and a differential mode interference absorbing unit, which respectively and individually absorb the common mode interference signal and the differential mode interference signal.

The common mode interference absorbing unit comprises a first patch Y capacitor C1 and a second patch Y capacitor C2, wherein one end of the first patch Y capacitor C1 is connected with the positive electrode of an input power supply, and the other end of the first patch Y capacitor C1 is grounded; one end of the second patch Y capacitor C2 is connected with the negative electrode of the input power supply, and the other end of the second patch Y capacitor C is connected with the power supply ground.

The differential mode interference absorption unit comprises a first magnetic bead L1 and a second magnetic bead L2, the first magnetic bead L1 and the second magnetic bead L2 are high-impedance magnetic beads for filtering differential mode interference, meanwhile, the first magnetic bead L1 and a first patch Y capacitor C1 form a first LC filter for filtering the positive electrode of a power supply, and the second magnetic bead L2 and a second patch Y capacitor C2 form a second LC filter for filtering the negative electrode of the power supply, so that interference signals can be filtered better.

The working principle of this example is:

because of the self characteristics of the direct current motor, abundant common mode/differential mode interference signals and surge voltages can be generated during normal operation, the bidirectional TVS tube D1 can absorb the corresponding surge voltages, and the surge voltages are prevented from being transmitted to a front-stage power circuit; l1 and L2 are high-resistance anti-magnetic beads which play a role of differential mode inductance and absorb differential mode interference signals generated by a direct current motor; c1 and C2 are SMD Y capacitors, and meanwhile, C1 and C2 are connected to the metal ground of the direct current motor to well filter common mode interference signals, and the SMD BDL filter U1 is respectively connected with the positive electrode and the negative electrode of the input voltage and is connected to the metal ground of the direct current motor, so that the SMD BDL filter has excellent common mode and differential mode inhibition effects. Through the absorption module and the filtering module, the interference signals generated by the direct current motor can be restrained greatly, and the standard requirements can be met.

Meanwhile, the filter circuit composed of the patch BDL filter U1, the first patch Y capacitor C1, the second patch Y capacitor C2, the first magnetic beads L1 and the second magnetic beads L2 can reduce external system noise and improve the anti-interference capability of the direct current motor.

Of course, as another embodiment of the present embodiment, the patch BDL filter U1 alone or the LC filter that filters out the common mode interference signal and the differential mode interference signal, respectively, may be provided alone. If space allows, the first magnetic bead L1 and the second magnetic bead L2 of the embodiment can also be replaced by inductors, and a good electromagnetic interference suppression effect is achieved by matching the absorption module and the patch BDL filter of the embodiment.

Because all the functional devices are patch devices, the utility model has small volume and simple encapsulation, can be made into a filter circuit board with small area, is convenient to install, and can be conveniently maintained and replaced when faults occur; because all the components are the surface mount devices, a universal filter circuit board corresponds to different direct current motors, the filter requirement can be met only by replacing the parameters of the corresponding components, the filter debugging is convenient, and the compatibility is strong.

The above embodiments are preferred embodiments of the present utility model, and are not intended to limit the scope of the present utility model, which includes but is not limited to the embodiments, and equivalent modifications according to the present utility model are within the scope of the present utility model.

Claims

1. A circuit for suppressing electromagnetic interference in a dc motor, comprising:

and a filtering module: the device is arranged at the output end of the input power supply and is used for filtering common mode interference signals and differential mode interference signals;

and an absorption module: is arranged between the filtering module and the direct current motor and is used for absorbing high-voltage pulses generated during the work of the direct current motor,

wherein, the functional elements of the filtering module and the absorbing module are patch elements.

2. The circuit for suppressing electromagnetic interference of a dc motor as recited in claim 1, wherein: the absorption module comprises a bidirectional TVS tube or a piezoresistor, and the bidirectional TVS tube or the piezoresistor is connected with the direct current motor in parallel.

3. The circuit for suppressing electromagnetic interference of a dc motor as recited in claim 2, wherein: the absorption module is a bidirectional TVS tube D1, one end of the bidirectional TVS tube D1 is connected with the positive electrode of the direct current motor, and the other end of the bidirectional TVS tube D1 is connected with the negative electrode of the direct current motor.

4. A circuit for suppressing electromagnetic interference in a dc motor according to any one of claims 1-3, wherein: the filtering module comprises a patch BDL filter U1, a power pin 1 of the patch BDL filter U1 is connected with the anode of an input power supply, a power pin 2 is connected with the cathode of the input power supply, and a first grounding pin 3 and a second grounding pin are respectively grounded.

5. A circuit for suppressing electromagnetic interference in a dc motor according to any one of claims 1-3, wherein: the filtering module comprises a common mode interference absorbing unit and a differential mode interference absorbing unit,

6. The circuit for suppressing electromagnetic interference of a dc motor as recited in claim 5, wherein: the differential mode interference absorption unit comprises a first magnetic bead L1 and a second magnetic bead L2, wherein the first magnetic bead L1 and the first patch Y capacitor C1 form a first LC filter for filtering the positive electrode of a power supply, and the second magnetic bead L2 and the second patch Y capacitor C2 form a second LC filter for filtering the negative electrode of the power supply.

7. The circuit for suppressing electromagnetic interference of a dc motor as recited in claim 6, wherein: the filtering module further comprises a patch BDL filter U1 arranged between the input power supply output end and the input ends of the common mode interference absorbing unit and the differential mode interference absorbing unit, a power supply pin 1 of the patch BDL filter U1 is connected with the positive electrode of an input power supply, a power supply pin 2 is connected with the negative electrode of the input power supply, and the first grounding pin 3 and the second grounding pin are respectively grounded.