Direct-current brushless motor

Abstract

The utility model discloses a direct current brushless motor which comprises a motor body and a motor controller, the motor body comprises a stator assembly, a rotor assembly, a rotating shaft and a shell, and the motor controller comprises a microprocessor, a power inversion unit and a Hall sensing circuit. The Hall sensing circuit detects position signals of the rotor assembly and transmits the position signals to the motor controller, the Hall sensing circuit comprises three sets of sensing elements, the two ends of the three sets of sensing elements are connected in parallel and jointly arranged on a printed circuit board, and the mechanical included angle between the first set of sensing element and the second set of sensing element is 60 degrees. The mechanical included angle between the second set of sensing elements and the third set of sensing elements is 60 degrees, so that the layout of the Hall sensing elements in the three-phase direct current motor is adjusted, the integration level is improved, and the space cost is saved.

Description

Technical Field

[0001] The utility model relates to the technical field of brushless motors, in particular to a brushless DC motor. Background Art

[0002] Brushless DC motors (BLDCs) are widely used in various automation equipment due to their high efficiency, low noise, and long life. However, for sensored three-phase BLDC motors used in home appliances, three surface-mount Hall effect sensors (SMD) are typically installed at a 120° angle to ensure the correct Hall effect phase sequence required for motor drive. In motor control systems, the placement of Hall effect sensors often requires significant space on the printed circuit board (PCB). In today's applications with stringent space and cost requirements, improving integration while saving space and cost has become a pressing issue. Summary of the Invention

[0003] The embodiment of the present invention provides a brushless DC motor to reduce and improve the integration of the brushless DC motor, saving space and cost.

[0004] In order to solve the above technical problems, an embodiment of the present application provides a brushless DC motor, including a motor body and a motor controller, wherein the motor body includes a stator assembly, a rotor assembly, a rotating shaft and a casing, and the motor controller includes a microprocessor, a power inverter unit and a Hall sensor circuit. The Hall sensor circuit detects the position signal of the rotor assembly and transmits it to the motor controller. The Hall sensor circuit includes three sets of sensing elements, and the two ends of the three sets of sensing elements are connected in parallel and arranged together on a printed circuit board. The mechanical angle between the first set of sensing elements and the second set of sensing elements is 60 degrees, and the mechanical angle between the second set of sensing elements and the third set of sensing elements is 60 degrees.

[0005] Optionally, the sensing element is a direct-insertion Hall sensor or a patch Hall sensor.

[0006] Optionally, the output signals of the first set of sensing elements and the third set of sensing elements have the same polarity, and the output signals of the first set of sensing elements, the third set of sensing elements and the second set of sensing elements have opposite polarities.

[0007] Optionally, the second set of sensing elements has opposite polarity to the first set of sensing elements and the third set of sensing elements.

[0008] Optionally, the first set of sensing elements and the third set of sensing elements are located on the same side of the printed circuit board, and the second sensing element is located on the other side of the printed circuit board.

[0009] Optionally, the sensing element is a direct-insertion Hall sensor, and the second sensing element is placed in an opposite direction to the first set of sensing elements and the third set of sensing elements.

[0010] Optionally, the first set of inductive elements, the second set of inductive elements and the third set of inductive elements are equidistant from the rotor assembly.

[0011] The brushless DC motor provided by an embodiment of the present invention includes a motor body and a motor controller, wherein the motor body includes a stator assembly, a rotor assembly, a rotating shaft and a housing, and the motor controller includes a microprocessor, a power inverter unit and a Hall sensor circuit. The Hall sensor circuit detects a position signal of the rotor assembly and transmits it to the motor controller. The Hall sensor circuit includes three sets of sensing elements, and the two ends of the three sets of sensing elements are connected in parallel and arranged together on a printed circuit board. The mechanical angle between the first set of sensing elements and the second set of sensing elements is 60 degrees, and the mechanical angle between the second set of sensing elements and the third set of sensing elements is 60 degrees. By adjusting the layout of the Hall sensor elements in the three-phase DC motor, the integration is improved and the space cost is saved. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0013] Figure 1 This is a schematic diagram of the structural layout of the Hall sensor in the three-phase brushless motor in the existing method;

[0014] Figure 2 This is the phase sequence change diagram corresponding to the three Hall sensors in the existing method;

[0015] Figure 3 This is a schematic diagram of the structural layout of the Hall sensor in the three-phase brushless motor of the present application;

[0016] Figure 4 This is another schematic diagram of the structural layout of the Hall sensor in the three-phase brushless motor of the present application;

[0017] Figure 5 This is a phase change diagram corresponding to the Hall sensor of this application.

[0018] Description of reference numerals:

[0019] A first set of sensing elements 1 , a second set of sensing elements 2 , a third set of sensing elements 3 , a printed circuit board 4 and a motor shaft 5 . DETAILED DESCRIPTION

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of the application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, not to describe a specific order.

[0021] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] Some proper nouns in this embodiment are explained as follows:

[0024] Hall sensor: Hall sensor is a magnetoelectric conversion device made of semiconductor materials based on the Hall effect principle. It can convert changes in magnetic field into electrical signal output.

[0025] Printed Circuit Board: Printed Circuit Board, PCB, is an electronic component that uses organic materials or inorganic substrates to wire, embed or mount components to achieve electrical connections and functions.

[0026] In the existing method, in order to detect the position information of the rotor of a three-phase brushless motor, three Hall sensors are usually placed on the stator of the motor. These sensors are placed at an angular position of every 120 degrees (mechanical angle) to achieve accurate detection of the motor rotor position, thereby providing the necessary position feedback for the control algorithm. Figure 1This is a schematic diagram of the layout of Hall sensors in a traditional three-phase brushless motor, showing the traditional installation location of the Hall sensors. The motor is simplified to a pair of poles for illustration. In this configuration, every time the motor rotor rotates 60 degrees, the three Hall sensors will change their output signals according to a specific combination sequence. Please refer to Figure 2 , Figure 2 This is a phase sequence change diagram corresponding to the three Hall sensors in the existing method, showing the phase sequence change of the three Hall sensors' outputs when the motor rotates counterclockwise.

[0027] Figure 1 In the figure, HallA, HallB and HallC are three Hall sensors, and their bottom surfaces are installed on the stator assembly of the motor. There is a mechanical angle of 120 degrees between HallA, HallB and HallC. This layout is used to obtain Figure 2 The phase sequence change diagram shown in the figure ensures that the Hall phase sequence required for motor driving is generated, where π / 3, π2 / 3, π, etc. are time periods.

[0028] To optimize the placement of Hall sensors to save space and cost, refer to Figure 3 , Figure 3 A brushless DC motor provided by an embodiment of the present invention is shown and described in detail as follows:

[0029] A brushless DC motor includes a motor body and a motor controller. The motor body includes a stator assembly, a rotor assembly, a rotating shaft, and a housing. The motor controller includes a microprocessor, a power inverter unit, and a Hall sensor circuit. The Hall sensor circuit detects a position signal of the rotor assembly and transmits it to the motor controller. The Hall sensor circuit includes three sets of sensing elements. The two ends of the three sets of sensing elements are connected in parallel and arranged together on a printed circuit board 4. The mechanical angle between the first set of sensing elements 1 and the second set of sensing elements 2 is 60 degrees, and the mechanical angle between the second set of sensing elements 2 and the third set of sensing elements 3 is 60 degrees.

[0030] Optionally, the sensing element is a direct-insertion Hall sensor or a patch Hall sensor.

[0031] Among them, through-hole Hall sensors are usually used in applications requiring higher current, while chip Hall sensors are suitable for automated surface mount production processes.

[0032] Optionally, the output signals of the first set of sensing elements 1 and the third set of sensing elements 3 have the same polarity, and the output signals of the first set of sensing elements 1 and the third set of sensing elements 3 and the second set of sensing elements 2 have opposite polarities.

[0033] Specifically, if Figure 3As shown, in this embodiment, the mechanical angle between the first set of sensing elements 1 and the second set of sensing elements 2 is 60 degrees, and the mechanical angle between the second set of sensing elements 2 and the third set of sensing elements 3 is 60 degrees. Figure 1 Compared with the traditional Hall sensor layout in FIG, the second set of sensing elements 2 is rotated 180 degrees along the motor shaft 5. This new layout reduces the area of the printed circuit board 4 (gray part) required by more than 60% compared with the original, effectively improving the system integration. However, it is necessary to ensure that the phase sequence change diagram obtained is as shown in FIG. Figure 2 The phase sequence of the Hall effect detectors is consistent with that shown in the figure, thereby ensuring the generation of the Hall effect phase sequence required for motor driving.

[0034] set up Figure 2 The Hall potential generated in HallC is U H , the applied magnetic field strength is B, and the Hall coefficient is R H , the material thickness is d, and the Hall potential after changing the placement direction is U H ', the magnetic field passing through the Hall sensor becomes a magnetic field B'(1) with constant magnitude and negative direction. According to the Hall effect formula (2), the Hall potential U H The current I, the applied magnetic field strength B and the Hall coefficient R H It is directly proportional to the material thickness d and inversely proportional to the material thickness d.

[0035] B'=-B (1)

[0036]

[0037] U H '=-U H (3)

[0038] It can be concluded that Figure 3 The Hall potential U after changing the placement direction H '(3) and the original Hall potential U H Same size, opposite direction.

[0039] It can be seen that before any processing is done, the layout of the three sets of sensing elements in this embodiment is that the second set of sensing elements 2 is Figure 2 The phase sequence changes shown in the figure have the same output signal phase and opposite polarity, while the first set of sensing elements 1 and the third set of sensing elements 3 are Figure 2The phase sequence changes shown are consistent, so it is necessary to ensure that the polarity of the output of the second set of sensing elements 2 is opposite to that of the traditional one. In this embodiment, the output signal polarity of the first set of sensing elements 1 and the third set of sensing elements 3 is the same, and the output signal polarity of the first set of sensing elements 1 and the third set of sensing elements 3 is opposite to that of the second set of sensing elements 2, ensuring that the Hall phase sequence required for motor drive is generated. At the same time, this design helps the motor controller identify the exact position and rotation direction of the rotor, saving space costs.

[0040] Optionally, the second set of sensing elements 2 has opposite polarity to the first set of sensing elements 1 and the third set of sensing elements 3 .

[0041] Optionally, the first set of sensing elements 1 and the third set of sensing elements 3 are located on the same side of the printed circuit board 4 , and the second sensing elements 2 are located on the other side of the printed circuit board 4 .

[0042] In a specific example, the placement of the second set of sensing elements 2 is changed from bottom placement to top placement, such as Figure 4 As shown. After doing so, the placement direction of the second set of sensing elements 2 is rotated 180 degrees, and accordingly, the direction of the magnetic field passing through the Hall sensor will also rotate 180 degrees. Figure 1 The same signal phase and polarity as HallC in the above example, the phase changes as Figure 5 shown.

[0043] This layout not only produces the Hall phase sequence required for motor drive, but also helps reduce interference between components and optimize the sensor's magnetic field detection range.

[0044] Optionally, the sensing element is a direct-insertion Hall sensor, and the second sensing element is placed in an opposite direction to the first set of sensing elements and the third set of sensing elements.

[0045] Specifically, for a direct-insertion Hall sensor, the polarity of the output signal can be changed by changing the installation direction of the Hall device instead of moving it from the bottom surface to the top surface.

[0046] Optionally, the first set of induction elements 1 , the second set of induction elements and the third set of induction elements 3 are at equal distances from the rotor assembly.

[0047] Specifically, the distance from all sensing elements to the rotor assembly should be consistent to ensure consistent and accurate signals. This uniformity of distance is crucial to ensuring smooth motor operation.

[0048] In this embodiment, by adjusting the layout of the Hall effect sensors in the three-phase DC motor, the integration level is improved and the space cost is saved.

[0049] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above embodiment methods can be implemented by means of software plus the necessary general hardware platform, and of course can also be implemented by hardware, but in many cases the former is a better implementation method.

[0050] Obviously, the embodiments described above are only some of the embodiments of the present application, rather than all of the embodiments. The preferred embodiments of the present application are given in the accompanying drawings, but they do not limit the patent scope of the present application. The present application can be implemented in many different forms. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive. Although the present application has been described in detail with reference to the aforementioned embodiments, for those skilled in the art, it is still possible to modify the technical solutions described in the aforementioned specific embodiments, or to make equivalent replacements for some of the technical features therein. Any equivalent structure made using the contents of the present application specification and the accompanying drawings, directly or indirectly used in other related technical fields, is also within the scope of patent protection of the present application.

Claims

1. A brushless DC motor comprising a motor body and a motor controller, wherein the motor body comprises a stator assembly, a rotor assembly, a rotating shaft, and a housing; the motor controller comprises a microprocessor, a power inverter unit, and a Hall effect sensor circuit, wherein the Hall effect sensor circuit detects a position signal of the rotor assembly and transmits it to the motor controller, characterized in that: The Hall sensor circuit includes three sets of sensing elements, which are connected in parallel at both ends and arranged together on a printed circuit board. Among them, the mechanical angle between the first set of sensing elements and the second set of sensing elements is 60 degrees, and the mechanical angle between the second set of sensing elements and the third set of sensing elements is 60 degrees.

2. The brushless DC motor according to claim 1, wherein: The sensing element is a direct-insertion Hall sensor or a patch Hall sensor.

3. The brushless DC motor according to claim 1, wherein: The output signals of the first set of sensing elements and the third set of sensing elements have the same polarity, and the output signals of the first set of sensing elements, the third set of sensing elements and the second set of sensing elements have opposite polarities.

4. The brushless DC motor according to claim 3, wherein: The second set of sensing elements has opposite polarities to the first set of sensing elements and the third set of sensing elements.

5. The brushless DC motor according to claim 3, wherein: The first set of sensing elements and the third set of sensing elements are located on the same side of the printed circuit board, and the second set of sensing elements is located on the other side of the printed circuit board.

6. The brushless DC motor according to claim 3, wherein: The sensing elements are direct-insertion Hall sensors, and the second set of sensing elements are placed in opposite directions to the first set of sensing elements and the third set of sensing elements.

7. The brushless DC motor according to claim 1, wherein: The first set of inductive elements, the second set of inductive elements, and the third set of inductive elements are equidistant from the rotor assembly.

Images