CN-224204991-U - Circuit structure for controlling anti-electromagnetic interference filter of motor

Abstract

The utility model discloses a circuit structure of a filter for controlling electromagnetic interference resistance of a motor, which comprises a differential mode inductor L1, a differential mode inductor L2, a common mode inductor L3 and a common mode inductor L4, wherein one input end of the differential mode inductor L1 and one input end of the differential mode inductor L2 are respectively connected with an input positive end P and an input negative end N, the other end of the differential mode inductor L1 is connected with one input end of the common mode inductor L3 and one end of a capacitor C1, the other end of the differential mode inductor L2 is respectively connected with the other input end of the common mode inductor L3 and the other end of the capacitor C1, one output end of the common mode inductor L3 is connected with the other end of the capacitor C2, the other end of the capacitor C3, one end of the capacitor C6 and the other input end of the common mode inductor L4, the other end of the capacitor C5 and the other end of the capacitor C6 are connected with a grounding end, one output end of the common mode inductor L4 is connected with one end of the capacitor C4 and one output positive end P ', and the other output end of the common mode inductor L4 is connected with the other end of the capacitor C4 and the positive end N'. The filter of the present utility model can provide high rejection capability.

Inventors

• PAN HUI

Assignees

• 贵阳顺络迅达电子有限公司

Dates

Publication Date

20260505

Application Date

20250530

Claims (2)

1. 1. A circuit structure of a filter for controlling electromagnetic interference resistance of a motor, which is characterized by comprising a differential mode inductor L1, a differential mode inductor L2, a common mode inductor L3 and a common mode inductor L4, wherein one input end of the differential mode inductor L1 and one input end of the differential mode inductor L2 are respectively connected with an input positive end P and an input negative end N, the other end of the differential mode inductor L1 is connected with one input end of the common mode inductor L3 and one end of a capacitor C1, the other end of the differential mode inductor L2 is respectively connected with the other input end of the common mode inductor L3 and the other end of the capacitor C1, one output end of the common mode inductor L3 is connected with the other end of the capacitor C2, the other end of the capacitor C3, one end of the capacitor C6 and the other input end of the common mode inductor L4, the other end of the capacitor C5 and the other end of the capacitor C6 are connected with a ground, one output end of the common mode inductor L4 is connected with one end of the capacitor C4 and one output positive end P ', and the other output end of the common mode inductor L4 is connected with the other end of the capacitor C4 and the positive end of the output N'.
2. 2. The circuit structure of the filter for motor control anti-electromagnetic interference according to claim 1, wherein the common-mode inductance L3 and the common-mode inductance L4 are symmetrically arranged on the input side and the output side of the circuit board.

Description

Circuit structure for controlling anti-electromagnetic interference filter of motor Technical Field The utility model relates to a circuit structure of a filter for controlling electromagnetic interference resistance of a motor, belonging to the technical field of filter circuits. Background When the brushless motor is started, the voltage overshoots at the moment of power-on, the magnetic field instantaneously changes to generate very strong current and electromagnetic field, sparks are easy to be caused, in addition, weak contact or friction is often generated and sparks are also good to be generated due to the fact that precision between a rotor and a stator of the brushless motor is insufficient and the magnetic field is repeatedly switched in the running process, when the motor rotates at high speed, conferences are conducted to a motor control system along with a power circuit of the brushless motor, and interference formed by conducting and switching of MOS (metal oxide semiconductor) tubes and diodes of the motor control system is coupled together and conducted out through a power interface of the motor control system, so that normal running of other equipment is interfered. By combining the running characteristics of the brushless motor and the interference conduction path, the electromagnetic interference and frequency multiplication electromagnetic interference of the brushless motor at the rotating speed of up to 20kHz-75kHz are restrained by installing a filter with high restraining capability in front of a power interface of a motor control system, so that the normal operation of other equipment is not influenced, and the problem is thoroughly solved on the conduction path by utilizing the filter. In general, the motor control system has limited module space, and the space for installing the filter is limited, and only the filter with the size of 51mmx31mm or smaller can be installed, however, the smaller filter often needs to consider space utilization and circuit layout, the suppression capability provided by the smaller filter is poor, and the problem is not solved by only one filter. Disclosure of utility model The utility model aims to solve the technical problem of providing a circuit structure of a filter for controlling electromagnetic interference resistance of a motor and providing high inhibition capability. The technical scheme includes that the circuit structure of the filter for controlling electromagnetic interference resistance of the motor comprises a differential mode inductor L1, a differential mode inductor L2, a common mode inductor L3 and a common mode inductor L4, wherein one input end of the differential mode inductor L1 and one input end of the differential mode inductor L2 are respectively connected with an input positive end P and an input negative end N, the other end of the differential mode inductor L1 is connected with one input end of the common mode inductor L3 and one end of the capacitor C1, the other end of the differential mode inductor L2 is respectively connected with the other input end of the common mode inductor L3 and the other end of the capacitor C1, one output end of the common mode inductor L3 is connected with one end of the capacitor C2, one end of the capacitor C3 and one input end of the common mode inductor L4, the other end of the capacitor C5 and the other end of the capacitor C6 are connected to the ground, one output end of the common mode inductor L4 is connected with one end of the capacitor C4 and one output positive end P ', and the other output end of the common mode inductor L4 is connected with the other output end of the capacitor C4 and the positive end N'. Further, the common-mode inductance L3 and the common-mode inductance L4 are symmetrically arranged on the input side and the output side of the circuit board. Compared with the prior art, the filter has the beneficial effects that the 3-level LC circuit design is adopted, and logic connection among common-mode inductors (L3 and L4), differential-mode inductors (L1 and L2) and capacitors (C1, C2, C3, C4, C5 and C6) is realized through circuit board layout. The common mode inductor L3, L4, C5 and C6 are connected in series to form a grounding loop, common mode rejection is realized by utilizing the high-resistance characteristic and the high-pass characteristic of the capacitor of the common mode inductor, the LC topology circuit is formed by L1 (L2) and C1, primary filtering is realized on differential mode interference, pi topology circuit is formed by leakage inductance of the common mode inductor L3 and C1 and C2, secondary filtering is further realized on differential mode interference, pi topology circuit is formed by leakage inductance of the common mode inductor L4 and C3 and C4, and tertiary filtering is realized on the differential mode interference again. The whole circuit can realize the suppression of common mode interference and differential mode interference of t