Brushless direct current motor based on brush control mode

Abstract

The utility model relates to a brushless direct-current motor, in particular to a brushless direct-current motor based on a brush control mode, and solves the technical problem that a brush motor in a shaped product cannot meet the long-service-life operation requirement in a high-altitude area or at a high altitude. According to the brushless DC motor based on the brush control mode provided by the utility model, the two non-inductive drivers with opposite connection directions of the positive and negative electrodes are arranged in the brushless motor body, the rotor of the brushless motor body is driven to rotate by adopting a non-inductive driving principle, and the corresponding non-inductive drivers are gated by utilizing the two diodes with opposite conduction directions, so that the brushless DC motor is driven to rotate. The purpose of changing the rotating direction of the motor by changing the positive and negative pole input directions of the power supply is achieved, the control mode is the same as the control mode of the brush motor, and lossless replacement of the brush motor can be achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a brushless DC motor, concretely relates to a brushless DC motor based on brush control mode. BACKGROUND

[0002] Brushed motor is widely used because of its relatively simple structure, mature technology and stable performance. The coil of the brushed motor is the rotor, and the start response is sensitive, the start torque is large, and the speed change is also relatively stable. Figure 1 As shown in FIG. 1, the size of the adjustable resistor R3 can be changed to change the size of the input voltage, thereby realizing the speed regulation of the brushed motor. Figure 2 As shown in FIG. 2, changing the direction of the input voltage can change the rotation direction of the brushed motor.

[0003] Although the brushed motor has many advantages, with the development of science and technology, the requirements for product performance are also increasing, not only requiring it to run in high-altitude areas or high-altitude environments, but also requiring it to have long service life and other characteristics. However, when the brushed motor runs in high-altitude or high-altitude, there is a possibility of ring fire between the commutator and the carbon brush, which not only affects the service life of the brushed motor, but also brings the risk of burning and explosion. Therefore, the brushed motor used in the finalized product obviously does not meet the above requirements.

[0004] The brushless DC motor does not have a commutator and a carbon brush, which fundamentally eliminates the possibility of ring fire when the motor runs in high-altitude areas or high-altitude environments, and has a long service life. In theory, as long as the structural parts of the brushless DC motor do not wear out, the brushless DC motor can run continuously. However, the control mode of the brushless DC motor is different from that of the brushed motor, and the control mode of the finalized product cannot be changed. Therefore, it is urgent to design a brushless DC motor using a brush control mode to replace the original brushed motor without damage, so as to meet the requirements of running in high-altitude areas or high-altitude environments and long service life. SUMMARY

[0005] The utility model aims at solving the technical problem that the brushed motor in the finalized product cannot meet the requirements of long service life running in high-altitude areas or high-altitude, and provides a brushless DC motor based on brush control mode.

[0006] To achieve the above-mentioned purpose, the utility model adopts the following technical scheme:

[0007] A brushless DC motor based on brush control mode, characterized in that it comprises a brushless motor body and a non-inductive drive unit arranged in the brushless motor body.

[0008] The non-inductive drive unit is sleeved on one end of the rotor of the brushless motor body, and comprises two non-inductive drivers for driving the forward rotation and reverse rotation of the rotor, respectively.

[0009] One of the sensorless drivers' positive terminals and the other sensorless driver's negative terminal are connected to one of the motor voltage input terminals of the brushless motor body, and the other sensorless driver's negative terminal and the other sensorless driver's positive terminal are connected to the other motor voltage input terminal of the brushless motor body.

[0010] A diode is connected in series between the negative terminal of each of the two sensorless drivers and the corresponding motor voltage input terminal, and the negative terminal of the diode is connected to the corresponding motor voltage input terminal.

[0011] The A, B, and C phases of the three-phase windings in the brushless motor body are respectively connected to the P, W, and M terminals of each sensorless driver.

[0012] Furthermore, the sensorless driver includes power MOSFETs Q1, Q2, Q3, Q4, Q5, and Q6;

[0013] The drains of power MOSFETs Q1, Q3, and Q5 serve as the positive terminals of the inductive driver, while the sources of power MOSFETs Q6, Q4, and Q2 serve as the negative terminals of the inductive driver.

[0014] The source of power MOSFET Q1 and the drain of Q6 are connected to the P terminal of the sensorless driver and the A phase of the three-phase winding in the brushless motor body. The source of power MOSFET Q3 and the drain of Q4 are connected to the W terminal of the sensorless driver and the B phase of the three-phase winding in the brushless motor body. The source of power MOSFET Q5 and the drain of Q2 are connected to the M terminal of the sensorless driver and the C phase of the three-phase winding in the brushless motor body.

[0015] Furthermore, a diode is connected in parallel between the source and drain of each of the power MOSFETs Q1, Q2, Q3, Q4, Q5 and Q6, with the source connected to the positive terminal of the diode and the drain connected to the negative terminal of the diode.

[0016] Furthermore, the sensorless driver adopts a sine wave control method or a square wave control method.

[0017] Furthermore, the duty cycle of the sensorless driver is 100%.

[0018] Furthermore, the brushless motor body has an iron core structure or a hollow cup structure.

[0019] The advantages of this utility model compared to the prior art are:

[0020] The brushless DC motor based on the brush control mode provided by the utility model is provided with two non-inductive drivers with opposite connection directions of positive and negative poles in the brushless motor body, adopts non-inductive driving principle to drive the rotation of the rotor of the brushless motor body, selects the corresponding non-inductive driver by two diodes with opposite conduction directions, and the rotation direction of the motor can be changed by changing the input direction of the positive and negative poles of the power supply, the control mode is the same as the control of the brush motor, and the brush motor can be replaced without loss. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is a speed regulation principle diagram of the existing brush motor;

[0022] Figure 2 It is a control principle diagram of the existing brush motor;

[0023] Figure 3 It is a structural schematic diagram of the utility model embodiment;

[0024] Figure 4 And Figure 5 It is a control principle diagram of the utility model embodiment, Figure 4 And Figure 5 The direction of input voltage is opposite;

[0025] Figure 6 It is a principle diagram of the non-inductive driver in the utility model embodiment;

[0026] The following is explained:

[0027] 1-brushless motor body, 2-non-inductive driving unit. DETAILED DESCRIPTION

[0028] In order to make the purpose, advantages and characteristics of the utility model more clear, the following combines the drawings and specific embodiments to make further detailed description on the brushless DC motor based on the brush control mode proposed by the utility model.

[0029] A brushless DC motor based on a brush control mode, as shown in Figure 3 It includes a brushless motor body 1 and a non-inductive driving unit 2 arranged in the brushless motor body 1, the non-inductive driving unit 2 is sleeved on the rotor of the brushless motor body 1, and includes two non-inductive drivers for driving the forward rotation and reverse rotation of the rotor respectively. The brushless motor body 1 has a core structure or a hollow cup structure. As Figure 4 , Figure 5As shown, the positive terminal of one sensorless driver and the negative terminal of the other sensorless driver are connected to one motor voltage input terminal of the brushless motor body 1, and the negative terminal of one sensorless driver and the positive terminal of the other sensorless driver are connected to the other motor voltage input terminal of the brushless motor body 1. A diode is connected in series between the negative terminals of the two sensorless drivers and the motor voltage input terminals, and the negative terminal of the diode is connected to the corresponding motor voltage input terminal. Therefore, both motor voltage input terminals can be connected to the positive and negative terminals of the power supply. Phases A, B, and C of the three-phase windings in the brushless motor body 1 are connected to the P, W, and M terminals of each sensorless driver, respectively.

[0030] The brushless DC motor based on brushed control provided in this embodiment includes two sets of sensorless drivers, such as... Figure 4 As shown, diode D1 conducts, and the sensorless driver connected to diode D1 begins to work. When the motor needs to work in the reverse direction, the positive and negative input directions of the power supply are reversed, as shown below. Figure 5 As shown, diode D2 is turned on, and the sensorless driver connected to diode D2 starts working. Changing the voltage can change the motor's speed, torque, current, etc. This control method is the same as that of a brushed motor, enabling non-destructive replacement of brushed motors.

[0031] like Figure 6 As shown, the sensorless driver includes power MOSFETs Q1, Q2, Q3, Q4, Q5, and Q6. The drains of power MOSFETs Q1, Q3, and Q5 serve as the positive terminals of the sensorless driver, while the sources of power MOSFETs Q6, Q4, and Q2 serve as the negative terminals. The source of power MOSFET Q1 and the drain of power MOSFET Q6 serve as the P-terminals of the sensorless driver, connected to phase A of the three-phase winding in the brushless motor body 1. The source of power MOSFET Q3 and the drain of power MOSFET Q4 serve as the W-terminals of the sensorless driver, connected to phase B of the three-phase winding in the brushless motor body 1. The source of power MOSFET Q5 and the drain of power MOSFET Q2 serve as the M-terminals of the sensorless driver, connected to phase C of the three-phase winding in the brushless motor body 1. A diode is connected in parallel between the source and drain of each power MOSFET Q1, Q2, Q3, Q4, Q5, and Q6, with the source connected to the positive terminal of the diode and the drain connected to the negative terminal of the diode.

[0032] When phases AB need to conduct, Q1 and Q4 are turned on, and the other power MOSFETs are turned off. The current flows from the positive terminal to Q1, phase A, phase B, Q4, and then to the negative terminal. When phases BC are conducted, Q3 and Q2 are turned on, and the other power MOSFETs are turned off. The current flows from the positive terminal to Q3, phase B, phase C, Q4, and then to the negative terminal. When phase CA is conducted, Q5 and Q6 are turned on, and the other power MOSFETs are turned off. The current flows from the positive terminal to Q5, phase C, phase A, Q6, and then to the negative terminal.

[0033] The non-inductive driver determines the position of the rotor by induced electromotive force, and determines the energization state at the next time according to the position of the rotor when rotating, and the time for the rotor to rotate to the next position is only related to the supply voltage, so the speed can be adjusted by adjusting the supply voltage, and this mode is similar to the brush motor. In addition, the speed can also be adjusted by adjusting the duty cycle of the non-inductive driver. However, in the embodiment, in order to make the speed adjustment simpler and match the control mode of the brush motor, the duty cycle of the non-inductive driver is 100%. The non-inductive driver adopts a sine wave control mode or a square wave control mode.

[0034] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the present application.

Claims

1. A brushless DC motor based on a brush control mode, characterized by: The brushless motor body (1) and the non-inductive driving unit (2) arranged in the brushless motor body (1); The non-inductive driving unit (2) is sleeved on one end of the rotor of the brushless motor body (1) and comprises two non-inductive drivers for driving the forward rotation and the reverse rotation of the rotor respectively; The positive electrode of one of the non-inductive drivers and the negative electrode of the other non-inductive driver are connected with one motor voltage input end of the brushless motor body (1), and the negative electrode of one of the non-inductive drivers and the positive electrode of the other non-inductive driver are connected with the other motor voltage input end of the brushless motor body (1); A diode is connected in series between the negative electrode of each non-inductive driver and the corresponding motor voltage input end, and the negative electrode of the diode is connected with the corresponding motor voltage input end. The A phase, the B phase and the C phase of the three-phase winding in the brushless motor body (1) are connected with the P end, the W end and the M end of each non-inductive driver respectively.

2. A brushless DC motor based on a brush control mode according to claim 1, characterized in that: The non-inductive driver comprises power field effect tubes Q1, Q2, Q3, Q4, Q5 and Q6. The drain of the power field effect tube Q1, Q3 and Q5 serves as the positive electrode of the non-inductive driver, and the source of the power field effect tube Q6, Q4 and Q2 serves as the negative electrode of the non-inductive driver. The source of the power field effect tube Q1 and the drain of the power field effect tube Q6 serve as the P end of the non-inductive driver and are connected with the A phase of the three-phase winding in the brushless motor body (1), the source of the power field effect tube Q3 and the drain of the power field effect tube Q4 serve as the W end of the non-inductive driver and are connected with the B phase of the three-phase winding in the brushless motor body (1), and the source of the power field effect tube Q5 and the drain of the power field effect tube Q2 serve as the M end of the non-inductive driver and are connected with the C phase of the three-phase winding in the brushless motor body (1).

3. A brushless DC motor based on a brush control mode according to claim 2, characterized in that: A diode is connected in parallel between the source and the drain of each power field effect tube Q1, Q2, Q3, Q4, Q5 and Q6, the positive electrode of the diode is connected with the source, and the negative electrode of the diode is connected with the drain.

4. A brushless DC motor based on a brush control mode according to any one of claims 1-3, characterized in that: The non-inductive driver adopts a sine wave control mode or a square wave control mode.

5. A brushless DC motor based on a brush control mode according to claim 4, characterized in that: The duty cycle of the non-inductive driver is 100%.

6. A brushless DC motor based on a brush control mode according to claim 5, characterized in that: The brushless motor body (1) has a core structure or a hollow cup structure.

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