Direct-current brushless frequency conversion device for table type range hood

Abstract

The utility model discloses a direct current brushless frequency conversion device for a table type range hood, which comprises an installation module, a driving module and a control module, the driving module and the control module are both installed on the installation module, and a control panel comprises a main control circuit, an interface circuit, a driving circuit, a rotating speed feedback circuit and a speed regulation circuit. And the interface circuit, the driving circuit, the rotating speed feedback circuit and the speed regulation circuit are electrically connected with the main control circuit respectively. According to the direct-current brushless frequency conversion device for the table type range hood, the control module and the driving module are integrated on the mounting module, driving is carried out through the main control circuit, the interface circuit, the driving circuit, the rotating speed feedback circuit and the speed regulation circuit, and the direct-current brushless frequency conversion device has the advantages of being high in integration level, low in noise, high in efficiency, stable in starting and the like.

Description

Technical Field

[0001] The utility model belongs to the technical field of direct current brushless frequency conversion motors, and in particular relates to a direct current brushless frequency conversion device for a desktop range hood. Background Art

[0002] With the improvement of the quality of life, tabletop range hoods are increasingly used in home kitchens. However, the traditional range hood motor has a relatively simple structure, low integration, and large size, which occupies a large space when installed. In addition, the traditional range hood motor control method often has problems such as high energy consumption, high noise, and low control accuracy. Therefore, the development of an integrated, efficient, energy-saving, and low-noise motor control device is of great significance to improving the performance of tabletop range hoods.

[0003] Therefore, further improvements are made to the above problems. Utility Model Content

[0004] The main purpose of the utility model is to provide a DC brushless frequency conversion device for a desktop range hood, which is linked by an installation module, a drive module and a control module, and the control module and the drive module are integrated into the installation module, and has the advantages of high integration, stable structure and small space occupation, and is linked by a main control circuit, an interface circuit, a drive circuit, a speed feedback circuit and a speed regulation circuit to drive a DC brushless frequency conversion motor (i.e., a drive module), and has the advantages of low noise, high efficiency, smooth start-up, large air volume, low maintenance cost, etc., which effectively improves the use effect of the range hood.

[0005] In order to achieve the above purpose, the utility model provides a DC brushless frequency conversion device for a desktop range hood, comprising a mounting module, a drive module and a control module, wherein the drive module and the control module are both mounted on the mounting module, wherein:

[0006] The mounting module comprises a bracket, a sealing ring and a bracket bottom plate, the bracket comprises an integrally formed first component and a second component, the first component is provided with a first accommodating cavity inside and the second component is provided with a second accommodating cavity inside, the first accommodating cavity and the second accommodating cavity are communicated; the first accommodating cavity is provided with a first bearing placement area and a second bearing placement area, the bracket bottom plate is fixedly mounted on a side of the second component away from the first component and the sealing ring is located between the bracket bottom plate and the second component;

[0007] The driving module comprises a stator core, a rotating shaft, a magnetic ring, a first bearing and a second bearing, the stator core is sleeved on the first component and the magnetic ring is sleeved on the stator core, the first end of the rotating shaft is located in the second accommodating cavity and the second end of the rotating shaft passes through the first accommodating cavity, the first bearing is installed in the first bearing placement area and the second bearing is installed in the second bearing placement area, and the first bearing and the second bearing are both sleeved on the rotating shaft;

[0008] The control module includes a control board and a connecting wire harness, the control board is built into the second accommodating cavity, and one end of the connecting wire harness is electrically connected to the control board;

[0009] The control board includes a main control circuit, an interface circuit (connected to a control terminal for obtaining speed control instructions, etc.), a drive circuit (driving MOSFET to drive a motor), a speed feedback circuit and a speed control circuit. The interface circuit, the drive circuit, the speed feedback circuit and the speed control circuit are electrically connected to the main control circuit, respectively, and the speed control circuit and the speed feedback circuit are electrically connected to the interface circuit, respectively, wherein:

[0010] The main control circuit includes a control chip U1, and the drive circuit includes a transistor Q1, a transistor Q2, and a transistor Q3, wherein the input ends of the transistor Q1, the transistor Q2, and the transistor Q3 are respectively electrically connected to the control chip U1, and the output ends of the transistor Q1, the transistor Q2, and the transistor Q3 are respectively connected to the enameled wire (UVW three-phase) wound around the stator core;

[0011] The interface circuit includes a connection terminal P1, the speed feedback circuit includes a resistor R20 and a resistor R19, the common terminal of the resistor R20 and the resistor R19 is electrically connected to the speed feedback terminal (pin 7) of the control chip U1, the end of the resistor R19 away from the resistor R20 is connected to the power supply terminal (VDD5) and the end of the resistor R20 away from the resistor R19 is connected to the first end of the connection terminal P1 (pin 1, used to obtain a speed command);

[0012] The speed regulation circuit includes a diode D2 and a resistor R15, wherein the resistor R15 is connected to the anode of the diode D5 and the cathode of the diode D5 is connected to the third end (pin 3) of the connection end P1 and the end of the resistor R15 away from the diode D2 is connected to the speed regulation end (pin 8) of the control chip U1.

[0013] As a further preferred technical solution of the above technical solution, the outer wall of the first component is provided with a plurality of mounting ridges and the inner wall of the stator core is provided with a plurality of mounting grooves, and the mounting ridges are installed in the mounting grooves.

[0014] As a further preferred technical solution of the above technical solution, the driving module also includes a shell and a sleeve, the magnetic ring is fixedly installed on the inner wall of the shell, the second end of the rotating shaft passes through the shell, the inner wall of the sleeve is sleeved and fixed on the second end of the rotating shaft and the outer wall of the sleeve is fixedly connected to the shell.

[0015] As a further preferred technical solution of the above technical solution, the second component is provided with a wire harness mounting end and a wire crimping plate, one end of the connecting wire harness is installed between the wire harness mounting end and the wire crimping plate, and the connecting wire harness is sleeved with a heat shrink tube.

[0016] As a further preferred technical solution of the above technical solution, the second component is provided with a plurality of connection holes (for installing and fixing the entire motor).

[0017] As a further preferred technical solution of the above technical solution, the first path of pin 1 of the transistor Q1 is electrically connected to pin 12 of the control chip U1 through a resistor R4, the second path of pin 1 of the transistor Q1 is electrically connected to pin 17 of the control chip U1 through a resistor R9, the third path of pin 1 of the transistor Q1 is electrically connected to pin 20 of the control chip U1 through a resistor R21, the pin 2 of the transistor Q1 is electrically connected to pin 2 of the control chip U1 through a resistor R1, and the pin 4 of the transistor Q1 is electrically connected to pin 5 of the control chip U1 through a resistor R1;

[0018] Pin 1 of the transistor Q2 is electrically connected to pin 13 of the control chip U1 through a resistor R5, pin 2 of the transistor Q2 is electrically connected to pin 1 of the control chip U1 through a resistor R5, and pin 4 of the transistor Q2 is electrically connected to pin 4 of the control chip U1 through a resistor R5;

[0019] Pin 1 of the transistor Q3 is electrically connected to pin 16 of the control chip U1 through resistor R10, pin 2 of the transistor Q3 is electrically connected to pin 24 of the control chip U1 through resistor R12, and pin 4 of the transistor Q3 is electrically connected to pin 3 of the control chip U1 through resistor R13.

[0020] As a further preferred technical solution of the above technical solution, a resistor RS1 and a resistor RS2 are connected in parallel between the pin 1 of the transistor Q1 and the pin 1 of the transistor Q2;

[0021] A resistor RS3 and a resistor RS4 are connected in parallel between the pin 1 of the transistor Q1 and the pin 1 of the transistor Q3;

[0022] Pin 1 of the transistor Q1 is also electrically connected to pin 19 of the control chip U1 through resistors RS6 and R11. Both ends of the resistor RS6 are connected in parallel with resistor RS5, and one end of the resistor RS6 away from the transistor Q1 is grounded.

[0023] As a further preferred technical solution of the above technical solution, the two ends of the resistor RS2 are further connected in parallel with a capacitor C5, the two ends of the resistor RS3 are further connected in parallel with a capacitor C10, and the two ends of the resistor RS5 are further connected in parallel with a capacitor C9.

[0024] As a further preferred technical solution of the above technical solution, the control board further includes a zero-crossing detection circuit, and the zero-crossing detection circuit includes a resistor R22, a resistor R23 and a resistor R24, wherein:

[0025] One end of the resistor R22 is connected to the U phase interface and the other end of the resistor R22 is connected to the 18 pin of the control chip U1;

[0026] One end of the resistor R23 is connected to the V phase interface and the other end of the resistor R23 is connected to the 15 pin of the control chip U1;

[0027] One end of the resistor R24 ​​is connected to the W phase interface and the other end of the resistor R24 ​​is connected to the 14th pin of the control chip U1. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The utility model is a structural schematic diagram of a DC brushless frequency conversion device for a tabletop range hood.

[0029] Figure 2 The utility model is a cross-sectional view of a DC brushless frequency conversion device for a tabletop range hood.

[0030] Figure 3 It is a structural schematic diagram of a DC brushless frequency conversion device for a desktop range hood of the utility model (the outer shell is hidden).

[0031] Figure 4 The utility model is a structural schematic diagram of a bracket of a DC brushless frequency conversion device for a desktop range hood.

[0032] Figure 5 The utility model is a structural schematic diagram of a bracket of a DC brushless frequency conversion device for a desktop range hood.

[0033] Figure 6 The utility model is an exploded view of a DC brushless frequency conversion device for a desktop range hood.

[0034] Figure 7 The utility model discloses a main control circuit diagram of a DC brushless frequency conversion device for a table-top range hood.

[0035] Figure 8 The utility model discloses an interface circuit diagram of a DC brushless frequency conversion device for a table-top range hood.

[0036] Fig. 9 The utility model discloses a driving circuit diagram of a DC brushless frequency conversion device for a table-top range hood.

[0037] Fig.10 The utility model discloses a speed feedback circuit diagram of a DC brushless frequency conversion device for a table-top range hood.

[0038] Fig.11 The utility model discloses a speed regulating circuit diagram of a DC brushless frequency conversion device for a table-top range hood.

[0039] Fig.12 The utility model discloses a zero-crossing detection circuit diagram of a DC brushless frequency conversion device for a table-top range hood.

[0040] The reference numerals include: 100, mounting module; 110, bracket; 111, first component; 1111, first accommodating cavity; 1112, first bearing placement area; 1113, second bearing placement area; 1114, mounting convex strip; 112, second component; 1121, second accommodating cavity; 1122, wiring harness mounting end; 1123, wire pressing plate; 1124, connecting hole; 120, sealing ring; 130, bracket bottom plate; 200, drive module; 210, stator core; 211, mounting groove; 220, rotating shaft; 230, magnetic ring; 240, first bearing; 250, second bearing; 260, housing; 270, bushing; 300, control module; 310, control board; 320, connecting wiring harness; 330, heat shrink tube. DETAILED DESCRIPTION

[0041] The following description is used to disclose the utility model so that those skilled in the art can implement the utility model. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations. The basic principles of the utility model defined in the following description can be applied to other embodiments, variations, improvements, equivalents, and other technical solutions that do not deviate from the spirit and scope of the utility model.

[0042] The utility model discloses a DC brushless frequency conversion device for a tabletop range hood. The specific embodiments of the utility model are further described below in conjunction with preferred embodiments.

[0043] In the embodiments of the present invention, those skilled in the art will note that the tabletop range hood and the like involved in the present invention may be regarded as prior art.

[0044] Preferred embodiments.

[0045] like Figure 1-12 As shown, the utility model discloses a DC brushless frequency conversion device for a desktop range hood, comprising a mounting module 100, a driving module 200 and a control module 300, wherein the driving module 200 and the control module 300 are both mounted on the mounting module 100, wherein:

[0046] The mounting module 100 includes a bracket 110, a sealing ring 120 and a bracket bottom plate 130. The bracket 110 includes an integrally formed first component 111 and a second component 112. The first component 111 is provided with a first accommodating cavity 1111 and the second component 112 is provided with a second accommodating cavity 1121. The first accommodating cavity 1111 is communicated with the second accommodating cavity 1121. The first accommodating cavity 1111 is provided with a first bearing placement area 1112 and a second bearing placement area 1113. The bracket bottom plate 130 is fixedly installed on a side of the second component 112 away from the first component 111 and the sealing ring 120 is located between the bracket bottom plate 130 and the second component 112.

[0047] The driving module 200 includes a stator core 210, a rotating shaft 220, a magnetic ring 230, a first bearing 240 and a second bearing 250. The stator core 210 is sleeved on the first component 111 and the magnetic ring 230 is sleeved on the stator core 210 (a gap is provided between the magnetic ring and the stator core). The first end of the rotating shaft 220 is located in the second accommodating cavity 1121 and the second end of the rotating shaft 220 passes through the first accommodating cavity 1111. The first bearing 240 is installed in the first bearing placement area 1112 and the second bearing 250 is installed in the second bearing placement area 1113. The first bearing 240 and the second bearing 250 are both sleeved on the rotating shaft 220.

[0048] The control module 300 includes a control board 310 and a connection harness 320. The control board 310 is built into the second accommodating cavity 1121. One end of the connection harness 320 is electrically connected to the control board 310.

[0049] The control board 310 includes a main control circuit, an interface circuit (connected to a control terminal for obtaining speed control instructions, etc.), a drive circuit (driving MOSFET to drive a motor), a speed feedback circuit and a speed control circuit. The interface circuit, the drive circuit, the speed feedback circuit and the speed control circuit are electrically connected to the main control circuit, respectively, and the speed control circuit and the speed feedback circuit are electrically connected to the interface circuit, respectively, wherein:

[0050] The main control circuit includes a control chip U1, and the drive circuit includes a transistor Q1, a transistor Q2, and a transistor Q3, wherein the input ends of the transistor Q1, the transistor Q2, and the transistor Q3 are respectively electrically connected to the control chip U1, and the output ends of the transistor Q1, the transistor Q2, and the transistor Q3 are respectively connected to the enameled wire (UVW three-phase) wound around the stator core;

[0051] The interface circuit includes a connection terminal P1 (i.e., a connection terminal for connecting the wiring harness), the speed feedback circuit includes a resistor R20 and a resistor R19, the common terminal of the resistor R20 and the resistor R19 is electrically connected to the speed feedback terminal (pin 7) of the control chip U1, the end of the resistor R19 away from the resistor R20 is connected to the power supply terminal (VDD5), and the end of the resistor R20 away from the resistor R19 is connected to the first end of the connection terminal P1 (pin 1, used to obtain a speed command);

[0052] The speed regulation circuit includes a diode D2 and a resistor R15, wherein the resistor R15 is connected to the anode of the diode D5 and the cathode of the diode D5 is connected to the third end (pin 3) of the connection end P1 and the end of the resistor R15 away from the diode D2 is connected to the speed regulation end (pin 8) of the control chip U1.

[0053] Specifically, the outer wall of the first component 111 is provided with a plurality of mounting ridges 1114 and the inner wall of the stator core 210 is provided with a plurality of mounting grooves 211 , and the mounting ridges 1114 are installed in the mounting grooves 211 .

[0054] More specifically, the driving module 200 also includes a shell 260 and a sleeve 270, the magnetic ring 230 is fixedly installed on the inner wall of the shell 260, the second end of the rotating shaft 270 passes through the shell 260, the inner wall of the sleeve 270 is sleeved and fixed on the second end of the rotating shaft 220, and the outer wall of the sleeve 270 is fixedly connected to the shell 260.

[0055] Furthermore, the second component 112 is provided with a harness mounting end 1122 and a wire pressing plate 1123 , one end of the connecting harness 320 is mounted between the harness mounting end 1122 and the wire pressing plate 1123 , and the connecting harness 320 is sleeved with a heat shrink tube 330 .

[0056] Furthermore, the second component 112 is provided with a plurality of connection holes 1124 (for mounting and fixing the entire motor);

[0057] Specifically, the first path of pin 1 of the transistor Q1 is electrically connected to pin 12 of the control chip U1 through a resistor R4, the second path of pin 1 of the transistor Q1 is electrically connected to pin 17 of the control chip U1 through a resistor R9, the third path of pin 1 of the transistor Q1 is electrically connected to pin 20 of the control chip U1 through a resistor R21, the pin 2 of the transistor Q1 is electrically connected to pin 2 of the control chip U1 through a resistor R1, and the pin 4 of the transistor Q1 is electrically connected to pin 5 of the control chip U1 through a resistor R1;

[0058] Pin 1 of the transistor Q2 is electrically connected to pin 13 of the control chip U1 through a resistor R5, pin 2 of the transistor Q2 is electrically connected to pin 1 of the control chip U1 through a resistor R5, and pin 4 of the transistor Q2 is electrically connected to pin 4 of the control chip U1 through a resistor R5;

[0059] Pin 1 of the transistor Q3 is electrically connected to pin 16 of the control chip U1 through resistor R10, pin 2 of the transistor Q3 is electrically connected to pin 24 of the control chip U1 through resistor R12, and pin 4 of the transistor Q3 is electrically connected to pin 3 of the control chip U1 through resistor R13.

[0060] More specifically, a resistor RS1 and a resistor RS2 are connected in parallel between the pin 1 of the transistor Q1 and the pin 1 of the transistor Q2;

[0061] A resistor RS3 and a resistor RS4 are connected in parallel between the pin 1 of the transistor Q1 and the pin 1 of the transistor Q3;

[0062] Pin 1 of the transistor Q1 is also electrically connected to pin 19 of the control chip U1 through resistors RS6 and R11. Both ends of the resistor RS6 are connected in parallel with resistor RS5, and one end of the resistor RS6 away from the transistor Q1 is grounded.

[0063] Furthermore, the two ends of the resistor RS2 are connected in parallel with a capacitor C5, the two ends of the resistor RS3 are connected in parallel with a capacitor C10, and the two ends of the resistor RS5 are connected in parallel with a capacitor C9.

[0064] Furthermore, the control board further includes a zero-crossing detection circuit, and the zero-crossing detection circuit includes a resistor R22, a resistor R23 and a resistor R24, wherein:

[0065] One end of the resistor R22 is connected to the U phase interface and the other end of the resistor R22 is connected to the 18 pin of the control chip U1;

[0066] One end of the resistor R23 is connected to the V phase interface and the other end of the resistor R23 is connected to the 15 pin of the control chip U1;

[0067] One end of the resistor R24 ​​is connected to the W phase interface and the other end of the resistor R24 ​​is connected to the 14th pin of the control chip U1.

[0068] For this utility model:

[0069] For mechanical structures:

[0070] The control board drives after receiving the control command transmitted by the connection harness, and the stator core (wound with enameled wire) remains stationary, so that the magnetic ring rotates equivalent to the outer rotor. Since the magnetic ring is connected to the inner wall of the outer shell, the outer shell rotates. Since the outer shell is connected to the rotating shaft through the shaft sleeve, the rotating shaft is ultimately driven to rotate.

[0071] For the circuit structure:

[0072] The control chip U1 receives the control signal input by the user interruption through the interface circuit, generates corresponding control instructions according to the control signal and the information fed back by the current detection circuit and the speed detection circuit, and drives the DC brushless variable frequency motor to operate through the drive circuit;

[0073] In the start-up control stage, the control chip U1 controls the motor start-up acceleration to be smooth by controlling the drive circuit, eliminates the interference factor of reverse bias on the motor during startup, and makes the DC brushless variable frequency motor start smoothly; in the speed control stage, the control chip U1 adjusts the control instruction according to the motor speed information fed back by the speed feedback circuit, and uses the PWM speed regulation method to control the motor speed during operation, so as to control the air volume and make the motor run at the target speed; in the power control stage, the control chip U1 adjusts the control instruction according to the motor current information fed back by the current detection circuit (composed of resistors RS1-RS6), so that the motor runs at the optimal power state;

[0074] The ground wire of the utility model is isolated and connected to the motor housing, which greatly improves the anti-static level, the maximum withstand voltage can reach 8kV, and the insulation withstand voltage level and safety reliability are improved.

[0075] It is worth mentioning that the technical features such as the desktop range hood involved in this utility model patent application should be regarded as prior art. The specific structure, working principle and possible control method and spatial layout method of these technical features can be selected according to the conventional methods in the field, and should not be regarded as the invention point of this utility model patent. This utility model patent will not be further elaborated.

[0076] For those skilled in the art, it is still possible to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present utility model should be included in the protection scope of the present utility model.

Claims

1. A DC brushless frequency conversion device for a tabletop range hood, characterized in that: It includes an installation module, a driving module and a control module, wherein the driving module and the control module are both installed on the installation module, wherein: The mounting module comprises a bracket, a sealing ring and a bracket bottom plate, the bracket comprises an integrally formed first component and a second component, the first component is provided with a first accommodating cavity inside and the second component is provided with a second accommodating cavity inside, the first accommodating cavity and the second accommodating cavity are communicated; the first accommodating cavity is provided with a first bearing placement area and a second bearing placement area, the bracket bottom plate is fixedly mounted on a side of the second component away from the first component and the sealing ring is located between the bracket bottom plate and the second component; The driving module comprises a stator core, a rotating shaft, a magnetic ring, a first bearing and a second bearing, the stator core is sleeved on the first component and the magnetic ring is sleeved on the stator core, the first end of the rotating shaft is located in the second accommodating cavity and the second end of the rotating shaft passes through the first accommodating cavity, the first bearing is installed in the first bearing placement area and the second bearing is installed in the second bearing placement area, and the first bearing and the second bearing are both sleeved on the rotating shaft; The control module includes a control board and a connecting wire harness, wherein the control board is built into the second accommodating cavity, and one end of the connecting wire harness is electrically connected to the control board; The control board includes a main control circuit, an interface circuit, a drive circuit, a speed feedback circuit and a speed regulation circuit, wherein the interface circuit, the drive circuit, the speed feedback circuit and the speed regulation circuit are electrically connected to the main control circuit respectively, and the speed regulation circuit and the speed feedback circuit are electrically connected to the interface circuit respectively, wherein: The main control circuit includes a control chip U1, and the drive circuit includes a transistor Q1, a transistor Q2, and a transistor Q3, wherein the input ends of the transistor Q1, the transistor Q2, and the transistor Q3 are respectively electrically connected to the control chip U1, and the output ends of the transistor Q1, the transistor Q2, and the transistor Q3 are respectively connected to the enameled wire wound around the stator core; The interface circuit includes a connection terminal P1, the speed feedback circuit includes a resistor R20 and a resistor R19, the common terminal of the resistor R20 and the resistor R19 is electrically connected to the speed feedback terminal of the control chip U1, the end of the resistor R19 away from the resistor R20 is connected to the power supply terminal and the end of the resistor R20 away from the resistor R19 is connected to the first end of the connection terminal P1; The speed regulation circuit includes a diode D2 and a resistor R15, wherein the resistor R15 is connected to the anode of the diode D5 and the cathode of the diode D5 is connected to the third end of the connection terminal P1 and one end of the resistor R15 away from the diode D2 is connected to the speed regulation end of the control chip U1.

2. A DC brushless frequency conversion device for a tabletop range hood according to claim 1, characterized in that: The outer wall of the first component is provided with a plurality of mounting ridges and the inner wall of the stator core is provided with a plurality of mounting grooves, and the mounting ridges are installed in the mounting grooves.

3. A DC brushless frequency conversion device for a tabletop range hood according to claim 2, characterized in that: The driving module also includes a shell and a sleeve, the magnetic ring is fixedly installed on the inner wall of the shell, the second end of the rotating shaft passes through the shell, the inner wall of the sleeve is sleeved and fixed on the second end of the rotating shaft, and the outer wall of the sleeve is fixedly connected to the shell.

4. A DC brushless frequency conversion device for a tabletop range hood according to claim 3, characterized in that: The second component is provided with a harness mounting end and a wire pressing plate, one end of the connecting harness is mounted between the harness mounting end and the wire pressing plate, and the connecting harness is sleeved with a heat shrink tube.

5. A DC brushless frequency conversion device for a tabletop range hood according to claim 4, characterized in that: The second component is provided with a plurality of connection holes.

6. A DC brushless frequency conversion device for a tabletop range hood according to claim 5, characterized in that: The first path of pin 1 of the transistor Q1 is electrically connected to pin 12 of the control chip U1 through a resistor R4, the second path of pin 1 of the transistor Q1 is electrically connected to pin 17 of the control chip U1 through a resistor R9, the third path of pin 1 of the transistor Q1 is electrically connected to pin 20 of the control chip U1 through a resistor R21, the pin 2 of the transistor Q1 is electrically connected to pin 2 of the control chip U1 through a resistor R1, and the pin 4 of the transistor Q1 is electrically connected to pin 5 of the control chip U1 through a resistor R1; Pin 1 of the transistor Q2 is electrically connected to pin 13 of the control chip U1 through a resistor R5, pin 2 of the transistor Q2 is electrically connected to pin 1 of the control chip U1 through a resistor R5, and pin 4 of the transistor Q2 is electrically connected to pin 4 of the control chip U1 through a resistor R5; Pin 1 of the transistor Q3 is electrically connected to pin 16 of the control chip U1 through resistor R10, pin 2 of the transistor Q3 is electrically connected to pin 24 of the control chip U1 through resistor R12, and pin 4 of the transistor Q3 is electrically connected to pin 3 of the control chip U1 through resistor R13.

7. A DC brushless frequency conversion device for a tabletop range hood according to claim 6, characterized in that: A resistor RS1 and a resistor RS2 are connected in parallel between the pin 1 of the transistor Q1 and the pin 1 of the transistor Q2; A resistor RS3 and a resistor RS4 are connected in parallel between the pin 1 of the transistor Q1 and the pin 1 of the transistor Q3; Pin 1 of the transistor Q1 is also electrically connected to pin 19 of the control chip U1 through resistors RS6 and R11 . Both ends of the resistor RS6 are connected in parallel with resistor RS5 , and one end of the resistor RS6 away from the transistor Q1 is grounded.

8. A DC brushless frequency conversion device for a tabletop range hood according to claim 7, characterized in that: The two ends of the resistor RS2 are connected in parallel with a capacitor C5 , the two ends of the resistor RS3 are connected in parallel with a capacitor C10 , and the two ends of the resistor RS5 are connected in parallel with a capacitor C9 .

9. A DC brushless frequency conversion device for a tabletop range hood according to claim 8, characterized in that: The control board further includes a zero-crossing detection circuit, which includes a resistor R22, a resistor R23 and a resistor R24, wherein: One end of the resistor R22 is connected to the U phase interface and the other end of the resistor R22 is connected to the 18 pin of the control chip U1; One end of the resistor R23 is connected to the V phase interface and the other end of the resistor R23 is connected to the 15 pin of the control chip U1; One end of the resistor R24 ​​is connected to the W phase interface and the other end of the resistor R24 ​​is connected to the 14th pin of the control chip U1.

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