Multi-gear constant-speed adjusting circuit for low-voltage brushless motor of electric hair cutter

Abstract

The utility model discloses a multi-gear constant-speed regulating circuit for a low-voltage brushless motor of an electric hair cutter. The multi-gear constant-speed regulating circuit comprises a main control circuit, a power supply circuit, a voltage detection circuit, an inverter circuit and a back electromotive force detection circuit, the output end of the power supply circuit is connected with the voltage detection circuit, the output end of the voltage detection circuit is connected with the master control circuit, the inverter circuit is connected with the output end of the master control circuit, the output end of the inverter circuit is connected with the driving device, the driving device is connected with the back electromotive force detection circuit, and the output end of the back electromotive force detection circuit is connected with the master control circuit. By the adoption of the design, the square wave output duty ratio is adjusted according to different input power supply voltages, the multi-gear constant speed function is achieved, different rotating speeds are adjusted according to different use requirements, the use smoothness of a product is improved, the rotating speed is stable, the working efficiency and the use experience are improved, the heating value of the product is reduced, the service life is prolonged, and the structure is simple and convenient to use. The cost is low, and the market reference prospect is relatively great.

Description

Technical Field

[0001] The utility model relates to the technical field of electric hair clippers, in particular to a multi-speed constant speed regulating circuit for a low-voltage brushless motor of an electric hair clipper. Background Art

[0002] Electric hair clippers are a common haircutting and hairdressing tool, and are one of the most commonly used tools for barbers. Traditional electric hair clippers are generally composed of fixed teeth, movable teeth, an adjustable handle, a housing, and electrical components installed in the housing. Electricity is required as a power source when in use. Common electric hair clippers on the market generally use the mains electricity to directly drive the motor, or use batteries to drive the motor. When the voltage and load remain unchanged, the motor maintains a stable speed.

[0003] The gear adjustment of existing electric clippers is usually based on the movement distance of the blade to adapt to cutting hair of different lengths. Since there is no function to adjust the running gear of the motor, the motor will always maintain a single speed regardless of the hair type being cut. This situation will cause the cutting to be unsmooth due to the influence of resistance when cutting some coarse and dense hair, and it is easy to increase the heat of the motor, thereby affecting the service life of the motor.

[0004] Therefore, it is urgent to design a multi-speed constant speed regulation circuit for a low-voltage brushless motor of an electric hair clipper to overcome the deficiencies of one or more of the above-mentioned prior arts. Summary of the invention

[0005] The utility model adopts the following technical solution to solve the above-mentioned technical problems: a multi-speed constant speed regulating circuit for a low-voltage brushless motor of an electric hair clipper, characterized in that it comprises: a main control circuit, a power supply circuit, a voltage detection circuit, an inverter circuit, and a back electromotive force detection circuit; the output end of the power supply circuit is connected to the voltage detection circuit, the output end of the voltage detection circuit is connected to the main control circuit, the inverter circuit is connected to the output end of the main control circuit, the output end of the inverter circuit is connected to a driving device, the driving device is connected to the back electromotive force detection circuit, and the output end of the back electromotive force detection circuit is connected to the main control circuit.

[0006] In a preferred embodiment, a driving current detection circuit is further included, and the driving current detection circuit is connected to the driving device and is used to detect the current flowing through the driving device.

[0007] In a preferred embodiment, the power supply circuit includes: capacitor C2, capacitor C3, voltage zener diode ZD1, resistor R20, and capacitor C6; the capacitor C2 and capacitor C3 are connected in series to filter the input voltage, the resistor R20 is connected to the capacitor C6, the voltage zener diode ZD1 is connected in series to the resistor R20, and the capacitor C6 is connected to the main control circuit.

[0008] In a preferred embodiment, the voltage detection circuit includes: a resistor R1, a resistor R2, and a capacitor C1; the resistor R1 and the resistor R2 are connected in series, and the capacitor C1 is connected in series with the resistor R1.

[0009] In a preferred embodiment, the inverter circuit comprises: a group of MOS tubes Q1, a group of MOS tubes Q2, and a group of MOS tubes Q3; the three groups of MOS tubes are respectively connected to the three-wire terminals of the driving device in a one-to-one correspondence.

[0010] In a preferred embodiment, the back electromotive force detection circuit includes: resistor R8, resistor R3, resistor R4, resistor R5, resistor R6, and resistor R7; the resistor R8 is connected to the U end of the driving device, the resistor R3 is connected to the V end of the driving device, the resistor R4 is connected to the W end of the driving device, the resistor R5 is connected in series with the resistor R8, the resistor R6 is connected in series with the resistor R3, the resistor R7 is connected in series with the resistor R4, and the resistors R5, R6, and R7 are connected in a common line to the main control circuit.

[0011] The beneficial effects of the utility model are: adjusting the square wave output duty cycle according to different input power supply voltages to achieve a multi-speed constant speed function, adjusting different rotation speeds according to different usage requirements, improving the smoothness of product use, and stabilizing the rotation speed, improving work efficiency and user experience, reducing product heat generation, extending service life, and having a simple structure and low cost, and having a large market prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a principle block diagram of the utility model;

[0013] Figure 2 This is the main control circuit schematic diagram of the utility model;

[0014] Figure 3 This is a schematic diagram of the power supply circuit of the utility model;

[0015] Figure 4 This is a schematic diagram of a voltage detection circuit of the utility model;

[0016] Figure 5 This is the inverter circuit schematic diagram of the utility model;

[0017] Figure 6 This is the principle diagram of the back electromotive force detection circuit of the utility model.

[0018] In the figure:

[0019] 10. Main control circuit; 11. Power supply circuit; 12. Voltage detection circuit; 13. Inverter circuit; 14. Back electromotive force detection circuit; 15. Current detection circuit; 16. Driving device. DETAILED DESCRIPTION

[0020] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific embodiments disclosed below.

[0021] In the description of the embodiments of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms, "connection" and "installation" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. In addition, "connection" can be a direct connection or an indirect connection through an intermediate medium. Among them, "fixed" means that they are connected to each other and the relative position relationship after connection remains unchanged. The directional terms mentioned in the embodiments of the present utility model, such as "inside", "outside", "top", "bottom", etc., are only reference to the directions of the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of the present utility model, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present utility model.

[0022] In the embodiments of the present invention, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0023] In the embodiment of the present invention, "and / or" is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0024] References to "one embodiment" or "some embodiments" etc. described in this specification mean that one or more embodiments of the utility model include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways. Therefore, the utility model is not limited to the specific embodiments disclosed below.

[0025] like Figure 1-Figure 6 As shown, the utility model provides a multi-speed constant speed regulating circuit of a low-voltage brushless motor of an electric hair clipper, characterized in that it comprises: a main control circuit 10, a power supply circuit 11, a voltage detection circuit 12, an inverter circuit 13, and a back electromotive force detection circuit 14; the output end of the power supply circuit 11 is connected to the voltage detection circuit 12, the output end of the voltage detection circuit 12 is connected to the main control circuit 10, the inverter circuit 13 is connected to the output end of the main control circuit 10, the output end of the inverter circuit 13 is connected to a drive device 16, the drive device 16 is connected to the back electromotive force detection circuit 14, and the output end of the back electromotive force detection circuit 14 is connected to the main control circuit 10;

[0026] Specifically, the power supply circuit 11 is connected to the power supply, and the power supply circuit 11 provides a stable voltage input to the main control circuit 10 for the operation of the main control circuit 10. The voltage detection circuit 12 is used to detect the voltage input by the power supply circuit 11 and send the voltage signal to the main control circuit 10. The VBUS pin of the main control circuit 10 reads the power supply voltage and sets the speed according to the voltage. For example, the input voltage of 4.5V sets the speed to 7000RPM, and the input voltage of 5V sets the speed to 9000RPM. The actual speed can be set according to usage requirements; the inverter circuit 13 receives the signal output by the main control circuit 10, and changes the current direction of the drive device 16 according to the received signal, thereby changing the direction of the magnetic flux to rotate the motor. The back electromotive force detection circuit 14 is used to detect the rotor position and speed of the drive device 16.

[0027] The driving device 16 is a brushless motor, which can be used continuously for a longer time and has a higher service life.

[0028] Furthermore, it also includes a driving current detection circuit 15 , which is connected to the driving device 16 and is used to detect the current flowing through the driving device 16 .

[0029] Specifically, the driving device 16 is also connected to a driving current detection circuit 15, which is used to detect the current flowing through the driving device 16. The driving current detection circuit 15 can also be connected to a protection circuit, which can turn on or off the protection circuit according to the current size to prevent the driving device 16 from burning out.

[0030] Furthermore, the power supply circuit 11 includes: a capacitor C2, a capacitor C3, a voltage zener diode ZD1, a resistor R20, and a capacitor C6; the capacitor C2 and the capacitor C3 are connected in series to filter the input voltage, the resistor R20 is connected to the capacitor C6, the voltage zener diode ZD1 is connected in series to the resistor R20, and the capacitor C6 is connected to the main control circuit 10;

[0031] Specifically, the power supply circuit 11 has two ports J4 and J6 connected to the positive and negative input lines, the input voltage is 3~5.5VDC, capacitors C2 and C3 filter the input voltage, one VCC supplies power to the inverter circuit 13, and the other is filtered by resistor R20 and capacitor C6, and the output VDD voltage is stabilized by the voltage regulator diode ZD1 for powering the main control circuit 10.

[0032] Furthermore, the voltage detection circuit 12 includes: a resistor R1, a resistor R2, and a capacitor C1; the resistor R1 and the resistor R2 are connected in series, and the capacitor C1 and the resistor R1 are connected in series;

[0033] Specifically, the power supply voltage enters from VCC, is divided by resistors R1 and R2, and is connected to the VBUS pin of the main control circuit 10 after filtering by capacitor C1, and enters the main control circuit 10. The main control circuit 10 sets different speed outputs according to different input voltages to achieve two-wire power supply and multi-speed constant speed.

[0034] Furthermore, the inverter circuit 13 includes: a MOS tube Q1 group, a MOS tube Q2 group, and a MOS tube Q3 group; the three groups of MOS tubes are respectively connected to the three-wire terminals of the driving device 16 in a one-to-one correspondence;

[0035] Specifically, each of the three groups of MOS tubes has two MOS tubes, each MOS tube is connected in parallel with a resistor, and the six MOS tubes form a UVW three-way inverter circuit 13. The main control circuit 10 outputs a PWM square wave through a six-step commutation method, and changes the current direction of the drive device 16 through the inverter circuit 13, thereby changing the direction of the magnetic flux to rotate the drive device 16.

[0036] Further, the back electromotive force detection circuit 14 includes: a resistor R8, a resistor R3, a resistor R4, a resistor R5, a resistor R6, and a resistor R7; the resistor R8 is connected to the U end of the driving device 16, the resistor R3 is connected to the V end of the driving device 16, the resistor R4 is connected to the W end of the driving device 16, the resistor R5 is connected in series with the resistor R8, the resistor R6 is connected in series with the resistor R3, the resistor R7 is connected in series with the resistor R4, and the resistors R5, R6, and R7 are connected in a common line to the main control circuit 10;

[0037] Specifically, the back electromotive force detection circuit 14 is composed of six resistors, which are connected to the UVW three-phase of the driving device 16. After the voltage enters, it is connected to the AD detection port in the main control circuit 10 through resistor voltage division to detect the rotor position and speed of the driving device 16.

[0038] The main control circuit 10 outputs six-way three-group PWM square wave drive inverter circuit 13 through its H_PW, L_NW, H_PV, L_NV, H_PU, and L_NU pins according to the set speed, and drives the motor. After the motor is started, the motor rotor position and speed are detected according to the back electromotive force detection circuit 14, and the output duty cycle is adjusted according to the deviation between the actual speed and the set speed to achieve constant speed control.

[0039] To summarize, the present application adjusts the square wave output duty cycle according to different input power supply voltages to achieve a multi-speed constant speed function. Different speeds can be adjusted according to different usage requirements to improve the smoothness of product use. The speed is stable, work efficiency and user experience are improved, product heat generation is reduced, service life is extended, and the structure is simple and the cost is low, so it has great market prospects.

[0040] The present invention is not limited to what is described in the specification and implementation modes, and therefore, additional advantages and modifications can be easily realized by those familiar with the art. Therefore, without departing from the spirit and scope of the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details, representative devices, and illustrative examples shown and described herein.

Claims

1. A multi-speed constant speed regulation circuit for a low-voltage brushless motor of an electric hair clipper, characterized in that: include: Main control circuit, power supply circuit, voltage detection circuit, inverter circuit, back electromotive force detection circuit; The output end of the power supply circuit is connected to the voltage detection circuit, the output end of the voltage detection circuit is connected to the main control circuit, the inverter circuit is connected to the output end of the main control circuit, the output end of the inverter circuit is connected to a drive device, the drive device is connected to the back electromotive force detection circuit, and the output end of the back electromotive force detection circuit is connected to the main control circuit.

2. The electric hair clipper low-voltage brushless motor multi-speed constant speed regulation circuit according to claim 1, characterized in that: It also includes a driving current detection circuit, which is connected to the driving device and is used to detect the current flowing through the driving device.

3. The electric hair clipper low-voltage brushless motor multi-speed constant speed regulation circuit according to claim 1, characterized in that: The power supply circuit includes: capacitor C2, capacitor C3, voltage zener diode ZD1, resistor R20, and capacitor C6; the capacitor C2 and capacitor C3 are connected in series to filter the input voltage, the resistor R20 is connected to the capacitor C6, the voltage zener diode ZD1 is connected in series to the resistor R20, and the capacitor C6 is connected to the main control circuit.

4. The electric hair clipper low-voltage brushless motor multi-speed constant speed regulation circuit according to claim 1, characterized in that: The voltage detection circuit includes: a resistor R1, a resistor R2, and a capacitor C1; the resistor R1 and the resistor R2 are connected in series, and the capacitor C1 is connected in series with the resistor R1.

5. The electric hair clipper low-voltage brushless motor multi-speed constant speed regulation circuit according to claim 1, characterized in that: The inverter circuit comprises: a group of MOS tubes Q1, a group of MOS tubes Q2, and a group of MOS tubes Q3; the three groups of MOS tubes are respectively connected to the three-wire terminals of the driving device in a one-to-one correspondence.

6. The electric hair clipper low-voltage brushless motor multi-speed constant speed regulation circuit according to claim 1, characterized in that: The back electromotive force detection circuit includes: resistor R8, resistor R3, resistor R4, resistor R5, resistor R6, and resistor R7; the resistor R8 is connected to the U end of the driving device, the resistor R3 is connected to the V end of the driving device, the resistor R4 is connected to the W end of the driving device, the resistor R5 is connected in series with the resistor R8, the resistor R6 is connected in series with the resistor R3, the resistor R7 is connected in series with the resistor R4, and the resistors R5, R6, and R7 are connected in a common line to the main control circuit.

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