Control method and device of brushless direct current motor, brushless direct current motor and storage medium

Abstract

The application relates to a control method and device of a brushless direct current motor and the brushless direct current motor. The winding direction of a stator winding is automatically judged, the power pin signal of a position sensor is determined according to the winding direction, then whether the phase difference between the phase current signal of the brushless direct current motor and the output waveform signal of the position sensor matches is detected, so as to exclude false judgment. The positive and negative winding directions of the stator winding of the brushless direct current motor are suitable for the same kind of position sensor, the universality is higher, material management cost is saved, installation failure rate is reduced, and assembly efficiency is improved.

Description

Technical Field

[0001] This application relates to the field of motor technology, and in particular to a control method, device, brushless DC motor and storage medium for a brushless DC motor. Background Technology

[0002] With the implementation of new energy efficiency standards, the demand for brushless DC motors in various electrical appliances has increased significantly. To achieve higher efficiency and lower cost, brushless DC motors are trending towards integration, miniaturization, and multi-pole design. Currently, multi-pole brushless DC motors with position sensors typically have two stator winding schemes: forward and reverse winding. However, the same forward and reverse winding scheme results in a 180° phase difference in the stator winding current, requiring motor controllers with different position sensor layouts. This leads to low standardization and increased material management costs. Summary of the Invention

[0003] The purpose of this application is to provide a control method, device and brushless DC motor for a brushless DC motor. The forward and reverse winding directions of the stator winding of the brushless DC motor are applicable to the same position sensor, which has high versatility, saves material management costs, reduces installation failure rate and improves assembly efficiency.

[0004] In a first aspect, embodiments of this application provide a control method for a brushless DC motor, comprising: determining the winding direction information of the stator winding of the brushless DC motor; determining the power supply pin signal of a position sensor based on the winding direction information of the stator winding, wherein the position sensor is used to detect the rotor position of the brushless DC motor; detecting whether the phase difference between the phase current signal of the brushless DC motor and the output waveform signal of the position sensor matches; and if they match, determining that the brushless DC motor is operating normally.

[0005] In one possible implementation, determining the stator winding direction information of the brushless DC motor includes: acquiring the phase current signal of the brushless DC motor and the output waveform signal of the position sensor; determining the stator winding direction based on the phase difference between the phase current signal and the output waveform signal of the position sensor. For example, if the stator winding is wound in the forward direction, the phase difference between the corresponding phase current signal and the output waveform signal of the position sensor is T; then, if the stator winding is wound in the reverse direction, the phase difference between the corresponding phase current signal and the output waveform signal of the position sensor is T ± 180°.

[0006] In one possible implementation, determining the power supply pin signal of the position sensor based on the stator winding direction information includes: if it is determined that the stator winding direction is consistent with the assumed winding direction, then the power supply pin signal of the position sensor remains unchanged; if it is determined that the stator winding direction is opposite to the assumed winding direction, then the power supply pin signal of the position sensor is switched.

[0007] In one possible implementation, if the phase difference between the detected phase current signal of the brushless DC motor and the output waveform signal of the position sensor does not match, the winding direction information of the stator winding of the brushless DC motor is determined again.

[0008] Secondly, embodiments of this application provide a control device for a brushless DC motor, employing the brushless DC motor control method described above. The control device includes: a judgment unit configured to judge the winding direction information of the stator winding of the brushless DC motor; a control unit configured to control the power pin signal of a position sensor based on the winding direction information of the stator winding, the position sensor being used to detect the rotor position of the brushless DC motor; and a detection unit configured to detect whether the phase difference between the phase current signal of the brushless DC motor and the output waveform signal of the position sensor matches; if they match, it is determined that the brushless DC motor is operating normally.

[0009] In one possible implementation, the judgment unit is further configured to acquire the phase current signal of the brushless DC motor and the output waveform signal of the position sensor, and determine the winding direction of the stator winding based on the phase difference between the phase current signal and the output waveform signal of the position sensor. For example, if the phase difference between the corresponding phase current signal and the output waveform signal of the position sensor is T when the stator winding is wound in the forward direction, then the phase difference between the corresponding phase current signal and the output waveform signal of the position sensor is T±180° when the stator winding is wound in the reverse direction.

[0010] In one possible implementation, the control unit is further configured to keep the power supply pin signal of the position sensor unchanged if it is determined that the winding direction of the stator winding is consistent with the assumed winding direction; and to control the switching of the power supply pin signal of the position sensor if it is determined that the winding direction of the stator winding is opposite to the assumed winding direction.

[0011] In one possible implementation, the detection unit is further configured to send a signal to the judgment unit if the phase difference between the detected phase current signal of the brushless DC motor and the output waveform signal of the position sensor does not match, so as to re-determine the winding direction information of the stator winding of the brushless DC motor.

[0012] Thirdly, embodiments of this application provide a brushless DC motor, including: a memory storing computer program instructions; and a processor that, when the computer program instructions are executed by the processor, implements any of the brushless DC motor control methods described above.

[0013] Fourthly, embodiments of this application provide a computer-readable storage medium including instructions that, when executed on a computer, cause the computer to perform any of the brushless DC motor control methods described above.

[0014] According to the brushless DC motor control method, apparatus, and brushless DC motor provided in this application, the stator winding direction is automatically determined, and the power supply pin signal of the position sensor is determined accordingly. Then, the phase difference between the phase current signal of the brushless DC motor and the output waveform signal of the position sensor is detected to eliminate false judgments. The forward and reverse winding directions of the stator winding of this brushless DC motor are applicable to the same position sensor, which has high versatility, saves material management costs, reduces installation failure rate, and improves assembly efficiency. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In addition, in the drawings, the same parts use the same reference numerals, and the drawings are not drawn to scale.

[0016] Figure 1 This is a top view of the stator winding structure of the brushless DC motor provided in an embodiment of this application;

[0017] Figure 2 Show Figure 1 A schematic diagram of the forward winding structure of the middle stator;

[0018] Figure 3 Show Figure 1 A schematic diagram of the reverse winding structure of the middle stator;

[0019] Figure 4 A schematic diagram showing commutation using a position sensor to detect the rotor position;

[0020] Figure 5 A flowchart illustrating the control method for a brushless DC motor provided in an embodiment of this application is shown.

[0021] Figure 6 This diagram illustrates the structure of the control device for a brushless DC motor provided in an embodiment of this application. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] The brushless DC motor provided in this application embodiment can be an inner rotor and outer stator structure, that is, the stator is set on the outer periphery of the rotor, and it is widely used in the fields of household appliances, electric vehicles and other technologies.

[0024] Taking a three-phase ten-pole brushless DC motor as an example, such as Figures 1 to 3 As shown, the stator of the brushless DC motor includes a stator core 1 and coil windings 2. The stator core 1 is made of silicon steel sheets with good magnetic permeability, which are stamped and stacked. The stator core 1 has 12 slots along the circumference, forming 12 teeth. Each tooth has a pole shoe at the end, allowing the coil to be directly wound on the stator tooth pole to form 12 armature winding coils 2, which together form the U, V, and W three-phase windings. The rotor includes a rotor core and 10 permanent magnets continuously distributed along the outer circumference of the rotor core as magnetic poles. The rotor core is also made of silicon steel sheets stacked and pressed into the shaft. Ten permanent magnets are evenly pasted on the outer circumference, and the ten permanent magnets are arranged in an alternating N and S pole configuration along the circumference. Then, the two ends are pressed together with rotor clamping rings, and bearings are installed to form the rotor.

[0025] Furthermore, the position of each phase armature winding relative to the permanent magnet pole is determined by a position sensor installed on the stator. The position sensor can be, for example, but not limited to, a Hall sensor. Using its output signal, the corresponding power switch in the inverter circuit that supplies power to the armature winding is driven by the electronic commutation circuit according to a certain logic, so as to control the on and off of the three-phase armature winding, so that the current direction of the three-phase armature winding is switched according to the rotor magnetic pole orientation, so that the rotor continues to rotate.

[0026] For example Figures 1 to 3 Taking the stator of a three-phase ten-pole brushless DC motor as an example, position sensors 3 are respectively set at the three positions of rotor commutation on the stator. In this embodiment, the position sensors 3 are Hall elements. The function of the Hall elements is to detect the position of the rotor, provide commutation information to the switching devices, control the conduction and cutoff of the switching devices, so that the current in the stator windings changes direction in sequence with the change of rotor position, forming a rotating magnetic field to drive the rotor to rotate.

[0027] like Figure 4 The diagram illustrates a commutation process using a position sensor to detect rotor position. The horizontal axis represents time or period, and the vertical axis represents the amplitude of the waveform output by the position sensor. t1 represents the time to reach a certain amplitude after crossing zero. The commutation principle is as follows: after crossing zero, at time t1, when the amplitude of the positive waveform (HP) is greater than a specific value (e.g., 0.3V) of the negative waveform (HN), the motor begins commutation. The electrical angle of the commutation point t1 is (T1 / T) × 360°.

[0028] Currently, in multi-pole brushless DC motors with position sensors, the stator windings typically have two schemes: forward winding and reverse winding. However, the same forward and reverse winding schemes for the stator windings will result in a 180° phase difference in the current of the stator windings. The microcontroller unit (MCU) needs to match different position sensor layouts and circuit board traces, resulting in low standardization and increased material management costs.

[0029] Therefore, the brushless DC motor and its control method provided in this application embodiment are applicable to the same position sensor in both the forward and reverse winding directions of the stator winding of the brushless DC motor, which has high versatility and saves material management costs.

[0030] Figure 5 The flowchart illustrates the control method for a brushless DC motor provided in an embodiment of this application.

[0031] See Figure 5 This application provides a control method for a brushless DC motor, including the following steps S1 to S3.

[0032] Step S1: Determine the winding direction information of the stator winding of the brushless DC motor;

[0033] Step S2: Determine the power supply pin signal of the position sensor based on the stator winding direction information. The position sensor is used to detect the rotor position of the brushless DC motor.

[0034] Step S3: Check whether the phase difference between the phase current signal of the brushless DC motor and the output waveform signal of the position sensor matches; if they match, it is determined that the brushless DC motor is operating normally.

[0035] According to the brushless DC motor control method provided in this application embodiment, the stator winding direction is automatically determined, and the power supply pin signal of the position sensor is determined accordingly. Then, the phase difference between the phase current signal of the brushless DC motor and the output waveform signal of the position sensor is detected to eliminate false judgments. The forward and reverse winding directions of the stator winding of this brushless DC motor are applicable to the same position sensor, without the need to change the layout of the position sensor and the circuit board wiring. It has high versatility, saves material management costs, reduces installation failure rate, and improves assembly efficiency.

[0036] Further, in step S1, determining the winding direction information of the stator winding of the brushless DC motor includes:

[0037] Step S11: Acquire the phase current signal of the brushless DC motor and the output waveform signal of the position sensor;

[0038] Step S12: Determine the winding direction of the stator winding based on the phase difference between the phase current signal and the output waveform signal of the position sensor. For example, if the stator winding is wound in the forward direction, the phase difference between the corresponding phase current signal and the output waveform signal of the position sensor is T. If the stator winding is wound in the reverse direction, the phase difference between the corresponding phase current signal and the output waveform signal of the position sensor is T ± 180°.

[0039] like Figure 4 As shown, since the rotor poles of a brushless DC motor are alternately set with N and S poles, the Hall element outputs a fixed waveform with alternating HP and HN when the brushless DC motor rotates. Furthermore, there is a specific relationship between the motor's phase current signal and the Hall element's output waveform signal. The system defaults to the initial stator winding direction being either forward or reverse winding. Assuming the phase relationship between the phase current signal and the Hall element's output waveform signal is T during forward winding, then during reverse winding, due to the 180° current phase difference, the phase relationship between the phase current signal and the Hall element's output waveform signal is T±180°. In this application, the microcontroller unit (MCU) can acquire the motor's phase current signal in real time through three sampling resistors. Based on the phase relationship between the phase current signal and the Hall element's output waveform signal, it can automatically determine whether the stator winding direction is forward or reverse winding.

[0040] Further, in step S2, determining the power supply pin signal of the position sensor based on the stator winding orientation information includes:

[0041] Step S21: If the winding direction of the stator winding is determined to be consistent with the assumed winding direction, then keep the power supply pin signal of the position sensor unchanged;

[0042] Step S22: If the winding direction of the stator winding is determined to be opposite to the assumed winding direction, the power supply pin signal of the control position sensor is switched.

[0043] The power supply pin signals of the Hall element include a "+" for the positive output port and a "-" for the negative output port. When the MCU determines that the actual winding direction of the stator winding is opposite to the default setting, the MCU switches the positive and negative output ports connected to the power supply pins of the Hall element, thereby causing the HP and HN waveforms of the Hall element to reverse, achieving a 180° phase difference with the current during reverse winding.

[0044] Furthermore, the control method for the brushless DC motor also includes: if the phase difference between the phase current signal of the brushless DC motor and the output waveform signal of the position sensor is mismatched, then the winding direction information of the stator winding of the brushless DC motor is determined again.

[0045] To eliminate false positives, after the MCU confirms the power supply pin signal of the Hall element, it again checks whether the stator winding direction information is correct. If the phase difference between the phase current signal of the brushless DC motor and the output waveform signal of the position sensor matches at this time, it is determined that the stator winding direction is consistent with the actual direction, and the motor continues to run in this state.

[0046] If the phase difference between the phase current signal of the brushless DC motor and the output waveform signal of the position sensor does not match at this time, for example, if the stator winding is initially determined to be wound in the correct direction, the phase difference between the phase current signal and the output waveform signal of the position sensor should be T, but the actual detected phase difference is T+180°, that is, the phase difference between the phase current signal and the output waveform signal of the position sensor does not match, then return to step S1 again to determine the winding direction information of the stator winding of the brushless DC motor, and switch the power supply pin signal of the position sensor accordingly.

[0047] Figure 6 This diagram illustrates the structure of the control device for a brushless DC motor provided in an embodiment of this application.

[0048] like Figure 6 As shown, the brushless DC motor control device provided in this application embodiment adopts the brushless DC motor control method described above. The control device includes: a judgment unit 10, a control unit 20, and a detection unit 30.

[0049] The judgment unit 10 is configured to judge the winding direction information of the stator winding of the brushless DC motor;

[0050] The control unit 20 is configured to control the power pin signal of the position sensor according to the winding direction information of the stator winding. The position sensor is used to detect the rotor position of the brushless DC motor.

[0051] The detection unit 30 is configured to detect whether the phase difference between the phase current signal of the brushless DC motor and the output waveform signal of the position sensor matches; if they match, it is determined that the brushless DC motor is operating normally.

[0052] Furthermore, the judgment unit 10 is further configured to acquire the phase current signal of the brushless DC motor and the output waveform signal of the position sensor, and determine the winding direction of the stator winding based on the phase difference between the phase current signal and the output waveform signal of the position sensor. For example, if the stator winding is wound in the forward direction, the phase difference between the corresponding phase current signal and the output waveform signal of the position sensor is T. When the stator winding is wound in the reverse direction, the phase difference between the corresponding phase current signal and the output waveform signal of the position sensor is T±180°.

[0053] Furthermore, the control unit 20 is further configured to keep the power supply pin signal of the position sensor unchanged if it is determined that the winding direction of the stator winding is consistent with the assumed winding direction; and to control the switching of the power supply pin signal of the position sensor if it is determined that the winding direction of the stator winding is opposite to the assumed winding direction.

[0054] Furthermore, the detection unit 30 is further configured to send a signal to the judgment unit if the phase difference between the phase current signal of the brushless DC motor and the output waveform signal of the position sensor does not match, so as to re-determine the winding direction information of the stator winding of the brushless DC motor.

[0055] It is understood that the brushless DC motor control device provided in this application embodiment is the execution subject of the aforementioned brushless DC motor control method. For the specific execution methods of each module, please refer to the content of the aforementioned brushless DC motor control method, which will not be repeated here.

[0056] The control device for a brushless DC motor provided in this application automatically determines the winding direction of the stator winding and accordingly determines the power supply pin signal of the position sensor. Then, it detects whether the phase difference between the phase current signal of the brushless DC motor and the output waveform signal of the position sensor matches to eliminate false judgments. The forward and reverse winding directions of the stator winding of this brushless DC motor are applicable to the same position sensor, resulting in high versatility, reduced material management costs, lower installation failure rates, and improved assembly efficiency.

[0057] In addition, this application embodiment also provides a brushless DC motor, including: a memory storing computer program instructions; and a processor that, when the computer program instructions are executed by the processor, implements the brushless DC motor control method as described above.

[0058] In addition, embodiments of this application also provide a computer-readable storage medium, characterized in that the computer-readable storage medium includes instructions that, when executed on a computer, cause the computer to perform the brushless DC motor control method as described above.

[0059] It should be noted that the terms "one embodiment," "embodiment," "exemplary embodiment," "some embodiments," etc., mentioned in the specification indicate that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not, is within the knowledge scope of those skilled in the art.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A control method for a brushless DC motor, characterized in that, include: The phase current signal of the brushless DC motor and the output waveform signal of the position sensor are acquired. The position sensor is used to detect the rotor position of the brushless DC motor. The winding direction of the stator winding is determined based on the phase difference between the phase current signal and the output waveform signal of the position sensor. If the phase difference between the phase current signal and the output waveform signal of the position sensor is determined to be a preset value T, then the power supply pin signal of the position sensor is kept unchanged. If the phase difference between the phase current signal and the output waveform signal of the position sensor is determined to be T±180°, then the power supply pin signal of the position sensor is switched. The phase difference between the phase current signal of the brushless DC motor and the output waveform signal of the position sensor is checked to see if they match. If the phase difference matches and is within the preset value, the brushless DC motor is determined to be operating normally.

2. The control method according to claim 1, characterized in that, Determining the stator winding direction based on the phase difference between the phase current signal and the output waveform signal of the position sensor includes: Assuming that when the stator winding is wound in the forward direction, the phase difference between the corresponding phase current signal and the output waveform signal of the position sensor is T, then when the stator winding is wound in the reverse direction, the phase difference between the corresponding phase current signal and the output waveform signal of the position sensor is T±180°.

3. The control method according to claim 1, characterized in that, If the phase difference between the detected phase current signal of the brushless DC motor and the output waveform signal of the position sensor does not match, the winding direction information of the stator winding of the brushless DC motor is determined again.

4. A control device for a brushless DC motor, employing the control method for a brushless DC motor as described in any one of claims 1 to 3, characterized in that, The control device includes: The judgment unit is configured to acquire the phase current signal of the brushless DC motor and the output waveform signal of the position sensor, and determine the winding direction of the stator winding based on the phase difference between the phase current signal and the output waveform signal of the position sensor. The position sensor is used to detect the rotor position of the brushless DC motor. The control unit is configured to keep the power pin signal of the position sensor unchanged if the phase difference between the phase current signal and the output waveform signal of the position sensor is determined to be a preset value T, and to control the power pin signal of the position sensor to switch if the phase difference between the phase current signal and the output waveform signal of the position sensor is determined to be T±180°. The detection unit is configured to detect whether the phase difference between the phase current signal of the brushless DC motor and the output waveform signal of the position sensor matches; if the phase difference matches and is within the preset value, the brushless DC motor is determined to be operating normally.

5. The control device according to claim 4, characterized in that, The judgment unit is further configured such that, assuming the stator winding is wound in the forward direction, the phase difference between the corresponding phase current signal and the output waveform signal of the position sensor is T, then when the stator winding is wound in the reverse direction, the phase difference between the corresponding phase current signal and the output waveform signal of the position sensor is T±180°.

6. The control device according to claim 4, characterized in that, The detection unit is further configured to send a signal to the judgment unit if the phase difference between the phase current signal of the brushless DC motor and the output waveform signal of the position sensor does not match, and to judge the winding direction information of the stator winding of the brushless DC motor again.

7. A brushless DC motor, characterized in that, include: Memory, which stores computer program instructions; A processor that, when the computer program instructions are executed by the processor, implements the control method for a brushless DC motor as described in any one of claims 1 to 3.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes instructions that, when executed on a computer, cause the computer to perform the control method for a brushless DC motor as described in any one of claims 1 to 3.

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