Motor winding direction detection device, drive assembly and electric tool

Abstract

The present disclosure relates to a motor winding direction detection device, a drive assembly and an electric tool, the device comprising a three-phase motor, a three-phase full-bridge inverter, a position detection module, a voltage detection module, a drive module and a winding direction judgment module, the drive module is used to inject a drive signal and a detection signal for a preset duration according to the position determined by the position detection module, wherein the position phase difference between the drive signal and the detection signal is a preset angle, and the drive signal and the detection signal are opposite signals; the voltage detection module is used to detect the first voltage of the non-conducting phase of the three-phase motor when the drive signal acts, and the second voltage of the non-conducting phase of the three-phase motor when the detection signal acts; the winding direction judgment module is used to determine the winding direction of the motor according to the first voltage and the second voltage. The embodiment of the present disclosure has the advantages of quickly identifying the forward and reverse winding of the motor, small motor loss, and good quietness at the start time.

Description

Technical Field

[0001] The present disclosure relates to the field of motor control technology, and in particular to a motor winding direction detection device, a drive assembly and an electric tool. Background Art

[0002] The motors used in current electric bicycles and other vehicles may have clockwise or counterclockwise winding problems due to problems with the manufacturer's production lines. If the clockwise and counterclockwise winding of the motor (that is, the positive and negative codes of the motor) cannot be identified, the motor may run away when the motor is being protected from theft and slope slip, affecting the safety of the user. Summary of the invention

[0003] According to one aspect of the present disclosure, a motor winding direction detection device is provided, the device comprising a three-phase motor, a three-phase full-bridge inverter, a position detection module, a voltage detection module, a drive module and a winding direction judgment module.

[0004] The three-phase full-bridge inverter comprises a first bridge arm, a second bridge arm and a third bridge arm, each bridge arm comprises an upper bridge arm and a lower bridge arm, and the upper bridge arm and the lower bridge arm of each bridge arm are provided with a transistor, and the three-phase full-bridge inverter is used to drive the three-phase motor, and the first bridge arm, the second bridge arm and the third bridge arm correspond to the first phase, the second phase and the third phase of the three-phase motor respectively;

[0005] The position detection module is used to determine the position of the rotor relative to the stator in the three-phase motor;

[0006] The driving module is connected to each transistor of the three-phase full-bridge inverter, and is used to inject a driving signal and a detection signal for a preset duration according to the position determined by the position detection module, wherein the positions of the driving signal and the detection signal differ by a preset angle, and the driving signal and the detection signal are opposite signals;

[0007] The voltage detection module is connected between the upper bridge arm and the lower bridge arm of each bridge arm of the three-phase full-bridge inverter, and is used to detect the first voltage of the non-conducting phase of the three-phase motor when the driving signal is applied, and the second voltage of the non-conducting phase of the three-phase motor when the detection signal is applied;

[0008] The winding direction determination module is connected to the voltage detection module, and is used to determine the winding direction of the motor according to the first voltage and the second voltage.

[0009] In a possible implementation manner, determining the winding direction of the motor according to the first voltage and the second voltage includes:

[0010] When the first voltage is less than the second voltage, determining that the winding direction of the motor is clockwise; or

[0011] When the first voltage is greater than or equal to the second voltage, it is determined that the winding direction of the motor is counterclockwise.

[0012] In a possible implementation manner, determining the winding direction of the motor according to the first voltage and the second voltage includes:

[0013] Respectively determine a first time duration and a second time duration for the first voltage and the second voltage to reach a preset voltage, wherein the first time duration and the second time duration are both shorter than the preset time duration;

[0014] When the first time length is less than the second time length, determining that the winding direction of the motor is clockwise; or

[0015] When the first time length is greater than or equal to the second time length, it is determined that the winding direction of the motor is counterclockwise.

[0016] In a possible implementation manner, the preset angle is 180°.

[0017] In a possible implementation manner, injecting a driving signal and a detection signal respectively for a preset duration according to the position determined by the position detection module includes:

[0018] When the angle of the rotor of the three-phase motor relative to the stator is 0°, injecting the drive signal for a preset time length;

[0019] When the angle of the rotor of the three-phase motor relative to the stator is 180°, the detection signal is injected for a preset time period.

[0020] In a possible implementation, the position detection module includes a Hall sensor.

[0021] In a possible implementation, the driving signal includes at least one of a first driving signal, a second driving signal, a third driving signal, a fourth driving signal, a fifth driving signal, and a sixth driving signal, wherein:

[0022] The first driving signal is used to drive the transistor of the upper bridge arm of the first bridge arm to be turned on and the transistor of the lower bridge arm of the third bridge arm to be turned on, and the non-conducting phase corresponding to the time period during which the first driving signal acts is the second phase;

[0023] The second driving signal is used to drive the transistor of the upper bridge arm of the second bridge arm to be turned on and the transistor of the lower bridge arm of the third bridge arm to be turned on, and the non-conducting phase corresponding to the time period during which the second driving signal acts is the first phase;

[0024] The third driving signal is used to drive the transistor of the upper bridge arm of the second bridge arm to be turned on and the transistor of the lower bridge arm of the first bridge arm to be turned on, and the non-conducting phase corresponding to the time period during which the third driving signal acts is the third phase;

[0025] The fourth driving signal is used to drive the transistor of the upper bridge arm of the third bridge arm to be turned on and the transistor of the lower bridge arm of the first bridge arm to be turned on, and the non-conducting phase corresponding to the time period during which the fourth driving signal acts is the second phase;

[0026] The fifth driving signal is used to drive the transistor of the upper bridge arm of the third bridge arm to be turned on and the transistor of the lower bridge arm of the second bridge arm to be turned on, and the non-conducting phase corresponding to the time period during which the fifth driving signal acts is the first phase;

[0027] The sixth driving signal is used to drive the transistor of the upper bridge arm of the first bridge arm to turn on and the transistor of the lower bridge arm of the second bridge arm to turn on. The non-conducting phase corresponding to the time period during which the sixth driving signal acts is the third phase.

[0028] In a possible implementation, the voltage detection module includes a first voltage detection unit, a second voltage detection unit, and a third voltage detection unit, which are respectively connected between the upper bridge arm and the lower bridge arm of each phase of the three-phase full-bridge inverter, wherein each voltage detection unit includes a first detection resistor and a second detection resistor,

[0029] The first end of the first detection resistor is connected between the upper bridge arm and the lower bridge arm of the corresponding phase, and the second end of the first detection resistor is connected to the first end of the second detection resistor, for outputting a detection voltage;

[0030] A second terminal of the second detection resistor is grounded.

[0031] According to one aspect of the present disclosure, a drive assembly is provided, wherein the drive assembly includes the motor drive device.

[0032] According to one aspect of the present disclosure, an electric tool is provided, comprising the driving assembly.

[0033] The embodiment of the present disclosure injects a drive signal and a detection signal for a preset time period respectively according to the position determined by the position detection module, wherein the position phase difference between the drive signal and the detection signal is a preset angle, and the drive signal and the detection signal are opposite signals. The first voltage of the non-conducting phase of the three-phase motor when the drive signal is applied and the second voltage of the non-conducting phase of the three-phase motor when the detection signal is applied are detected, thereby determining the winding direction of the motor according to the first voltage and the second voltage. The embodiment of the present disclosure can realize the recognition of the winding direction during the power-on initialization stage of the motor, without the need for traditional overhead learning, and can solve the anti-slip and anti-theft problems caused by power-on identification of the forward and reverse windings of the motor. In addition, the embodiment of the present disclosure uses the voltage method for judgment, which minimizes the motor loss to the greatest extent, and does not need to inject a voltage vector to reach the magnetic saturation state of the motor stator inductance, and the quietness at the startup moment is significantly improved.

[0034] It should be understood that the above general description and the following detailed description are exemplary and explanatory only and do not limit the present disclosure. Other features and aspects of the present disclosure will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The drawings herein are incorporated into the specification and constitute a part of the specification. These drawings illustrate embodiments consistent with the present disclosure and are used to illustrate the technical solutions of the present disclosure together with the specification.

[0036] Figure 1 A block diagram of a motor winding direction detection device according to an embodiment of the present disclosure is shown.

[0037] Figure 2 A schematic diagram of a motor driving device according to an embodiment of the present disclosure is shown.

[0038] Figure 3a A schematic diagram showing a magnetization curve of a stator core of a three-phase motor according to an embodiment of the present disclosure is shown, Figure 3b A schematic diagram showing a magnetization curve BH and a magnetic permeability curve μ-H of a ferromagnetic material used in a three-phase motor according to an embodiment of the present disclosure is shown.

[0039] Figure 3c A schematic diagram showing the relationship between the electronic inductance of a three-phase motor according to an embodiment of the present disclosure and the change in the angle between the magnetic potential generated by the armature winding and the permanent magnet magnetic potential. DETAILED DESCRIPTION

[0040] Various exemplary embodiments, features and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise specified.

[0041] In the description of the present disclosure, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply 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 present disclosure.

[0042] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present disclosure, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0043] In the present disclosure, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present disclosure can be understood according to specific circumstances.

[0044] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0045] The term "and / or" herein is only a description of the association relationship of the associated objects, indicating that there may 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 term "at least one" herein represents any combination of at least two of any one or more of a plurality of. For example, including at least one of A, B, and C can represent including any one or more elements selected from the set consisting of A, B, and C.

[0046] In addition, in order to better illustrate the present disclosure, numerous specific details are given in the following specific embodiments. It should be understood by those skilled in the art that the present disclosure can also be implemented without certain specific details. In some examples, methods, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present disclosure.

[0047] At present, the related technology for judging the direction of motor winding (learning positive and negative codes) still remains at the stage of putting the car in the air and letting the motor rotate to a high-speed learning stage. At present, the related technology has not yet completed the learning of positive and negative codes during the motor power-on initialization stage.

[0048] The embodiment of the present disclosure provides a motor winding direction detection device, which injects a drive signal and a detection signal for preset durations according to the position determined by the position detection module, wherein the position phase difference between the drive signal and the detection signal is a preset angle, and the drive signal and the detection signal are opposite signals. The first voltage of the non-conducting phase of the three-phase motor when the drive signal is applied and the second voltage of the non-conducting phase of the three-phase motor when the detection signal is applied are detected, thereby determining the winding direction of the motor according to the first voltage and the second voltage. The embodiment of the present disclosure can realize the recognition of the winding direction during the power-on initialization stage of the motor, without the need for overhead learning, and can solve the anti-slip and anti-theft problems caused by power-on identification of the forward and reverse windings of the motor. In addition, the embodiment of the present disclosure uses the voltage method for judgment, which reduces motor losses and does not require the injection of a voltage vector to reach the magnetic saturation state of the motor stator inductance, and the quietness at the startup moment is significantly improved.

[0049] See also Figure 1 , Figure 1 A block diagram of a motor winding direction detection device according to an embodiment of the present disclosure is shown.

[0050] like Figure 1 As shown, the device includes a three-phase motor 10, a three-phase full-bridge inverter 20, a position detection module 60, a voltage detection module 30, a drive module 40 and a winding direction determination module 50.

[0051] The three-phase full-bridge inverter 20 includes a first bridge arm, a second bridge arm and a third bridge arm, each bridge arm includes an upper bridge arm and a lower bridge arm, and the upper bridge arm and the lower bridge arm of each bridge arm are provided with a transistor. The three-phase full-bridge inverter 20 is used to drive the three-phase motor 10, and the first bridge arm, the second bridge arm, and the third bridge arm correspond to the first phase, the second phase, and the third phase of the three-phase motor 10 respectively;

[0052] The position detection module 60 is used to determine the position of the rotor relative to the stator in the three-phase motor 10;

[0053] The driving module 40 is connected to each transistor of the three-phase full-bridge inverter 20, and is used to inject a driving signal and a detection signal for a preset duration according to the position determined by the position detection module 60, wherein the positions of the driving signal and the detection signal differ by a preset angle, and the driving signal and the detection signal are opposite signals;

[0054] The voltage detection module 30 is connected between the upper bridge arm and the lower bridge arm of each bridge arm of the three-phase full-bridge inverter 20, and is used to detect the first voltage of the non-conducting phase of the three-phase motor 10 when the driving signal is applied, and the second voltage of the non-conducting phase of the three-phase motor 10 when the detection signal is applied;

[0055] The winding direction determination module 50 is connected to the voltage detection module 30 , and is used to determine the winding direction of the motor according to the first voltage and the second voltage.

[0056] It should be noted that each module and unit of the embodiment of the present disclosure may be implemented by a hardware circuit, or by using a general hardware circuit in combination with relevant existing logic.

[0057] First, possible implementations of the three-phase full-bridge inverter 20 are exemplarily introduced. It should be noted that the present disclosure does not limit possible implementations of the three-phase full-bridge inverter 20. In other implementations, the three-phase full-bridge inverter 20 may also have other implementations.

[0058] The following is an exemplary introduction to possible implementations of each module.

[0059] See also Figure 2 , Figure 2 A schematic diagram of a motor driving device according to an embodiment of the present disclosure is shown.

[0060] like Figure 2 As shown, the three-phase full-bridge inverter 20 may include a first transistor Q1, a second transistor Q2, a third transistor Q3, a fourth transistor Q4, a fifth transistor Q5, and a sixth transistor Q6, wherein the first transistor Q1 and the fourth transistor Q4 constitute a first bridge arm, and the fourth transistor Q4 is a lower bridge arm, the second transistor Q2 and the fifth transistor Q5 constitute a second bridge arm, and the fifth transistor Q5 is a lower bridge arm, the third transistor Q3 and the sixth transistor Q6 constitute a third bridge arm, and the sixth transistor Q6 is a lower bridge arm, wherein one end of each winding of the three-phase motor 10 is electrically connected, and the other end of each winding is electrically connected between the first transistor Q1 and the fourth transistor Q4, between the second transistor Q2 and the fifth transistor Q5, and between the third transistor Q3 and the sixth transistor Q6.

[0061] In a possible implementation, the first transistor Q1, the second transistor Q2, the third transistor Q3, the fourth transistor Q4, the fifth transistor Q5, and the sixth transistor Q6 may be metal-oxide-semiconductor field-effect transistors (MOSFET) and insulated gate bipolar transistors (IGBT), wherein the transistors may be implemented based on silicon carbide SiC and gallium nitride GaN to improve performance.

[0062] In one possible implementation, Figure 2 As shown, the three-phase full-bridge inverter 20 may further include multiple first input resistors, multiple second input resistors, and multiple input capacitors to filter the input signal. The stator of the three-phase motor 10 includes a first winding A, a second winding B, and a third winding C. The gates of the transistors of the three-phase full-bridge inverter 20 are electrically connected to the second end of the first input resistor, the first end of the second input resistor, and the first end of the input capacitor. The sources of the transistors of the three-phase full-bridge inverter 20 are electrically connected to the second end of the input capacitor and the second end of the second input resistor. The first end of the first input resistor is used to input a control signal.

[0063] The drain of the first transistor Q1, the drain of the second transistor Q2, and the drain of the third transistor Q3 are electrically connected, and the source of the fourth transistor Q4, the source of the fifth transistor Q5, and the source of the sixth transistor Q6 are electrically connected.

[0064] The source of the first transistor Q1 is electrically connected to the drain of the fourth transistor Q4 and the first end of the first winding, the source of the second transistor Q2 is electrically connected to the drain of the fifth transistor Q5 and the first end of the second winding, and the source of the third transistor Q3 is electrically connected to the drain of the sixth transistor Q6 and the first end of the third winding.

[0065] A second end of the first winding A, a second end of the second winding B, and a second end of the third winding C are grounded.

[0066] In one example, if Figure 2As shown, the first input resistor may include a first resistor R1, a third resistor R3, a fifth resistor R5, a seventh resistor R7, a ninth resistor R9, and an eleventh resistor R11; the second input resistor may include a second resistor R2, a fourth resistor R4, a sixth resistor R6, an eighth resistor R8, a tenth resistor R10, and a twelfth resistor R12; and the input capacitor may include a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, and a sixth capacitor C6.

[0067] In one example, the three-phase full-bridge inverter 20 may further include a plurality of freewheeling diodes disposed between the source and the drain of each transistor, for providing a freewheeling path when the transistor is turned off to prevent the transistor from being damaged.

[0068] In a possible implementation, the three-phase motor 10 may be a three-phase brushless DC motor.

[0069] In one example, the embodiment of the present disclosure realizes the Y connection (or star connection) of the three-phase motor 10 by electrically connecting one end of each winding of the stator, and the other end of each winding is electrically connected between the first transistor Q1 and the fourth transistor Q4, between the second transistor Q2 and the fifth transistor Q5, and between the third transistor Q3 and the sixth transistor Q6.

[0070] In one example, if Figure 2 As shown, the three-phase motor 10 may include a first winding A, a second winding B and a third winding C (corresponding to phase A, phase B, phase C, and corresponding to the first bridge arm, the second bridge arm, and the third bridge arm, respectively), one end of the first winding A is electrically connected between the first transistor Q1 and the fourth transistor Q4, one end of the second winding B is electrically connected between the second transistor Q2 and the fifth transistor Q5, and one end of the third winding C is electrically connected between the third transistor Q3 and the sixth transistor Q6.

[0071] In a possible implementation, Figure 2 As shown, the voltage detection module 30 may include a first voltage detection unit 310, a second voltage detection unit 320 and a third voltage detection unit 330, which are respectively connected between the upper bridge arm and the lower bridge arm of each phase of the three-phase full-bridge inverter 20, wherein each voltage detection unit includes a first detection resistor Re1 and a second detection resistor Re2,

[0072] The first end of the first detection resistor Re1 is connected between the upper bridge arm and the lower bridge arm of the corresponding phase, and the second end of the first detection resistor Re1 is connected to the first end of the second detection resistor Re2 for outputting the detection voltage Vde;

[0073] A second end of the second detection resistor Re2 is grounded.

[0074] In a possible implementation, the driving module 40 of the embodiment of the present disclosure may be implemented by a dedicated motor driving chip, or may be constructed by discrete components, which is not limited by the embodiment of the present disclosure.

[0075] The winding direction judgment module 50 of the disclosed embodiment may include a processing component, wherein the processing component includes but is not limited to a separate processor, or a discrete component, or a combination of a processor and a discrete component. The processor may include a controller having an execution instruction function in an electronic device, and the processor may be implemented in any appropriate manner, for example, by one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors or other electronic components. Inside the processor, the executable instructions may be executed by hardware circuits such as logic gates, switches, application-specific integrated circuits (ASICs), programmable logic controllers, and embedded microcontrollers. The disclosed embodiment does not limit the specific implementation of the winding direction judgment module 50.

[0076] In a possible implementation manner, determining the winding direction of the motor according to the first voltage and the second voltage may include:

[0077] When the first voltage is less than the second voltage, determining that the winding direction of the motor is clockwise; or

[0078] When the first voltage is greater than or equal to the second voltage, it is determined that the winding direction of the motor is counterclockwise.

[0079] The disclosed embodiment achieves rapid confirmation of the winding direction of the motor by determining that the winding direction of the motor is clockwise when the first voltage is less than the second voltage; or determining that the winding direction of the motor is counterclockwise when the first voltage is greater than or equal to the second voltage.

[0080] In a possible implementation manner, determining the winding direction of the motor according to the first voltage and the second voltage includes:

[0081] Respectively determine a first time duration and a second time duration for the first voltage and the second voltage to reach a preset voltage, wherein the first time duration and the second time duration are both shorter than the preset time duration;

[0082] When the first time length is less than the second time length, determining that the winding direction of the motor is clockwise; or

[0083] When the first time length is greater than or equal to the second time length, it is determined that the winding direction of the motor is counterclockwise.

[0084] The disclosed embodiment determines the first time duration and the second time duration for the first voltage and the second voltage to reach a preset voltage, respectively, and the first time duration and the second time duration are both less than the preset time duration; or when the first time duration is greater than or equal to the second time duration, determines that the winding direction of the motor is counterclockwise, thereby achieving rapid confirmation based on the winding direction of the motor.

[0085] The embodiment of the present disclosure does not limit the size of the preset voltage. For example, the preset voltage can be less than the power supply voltage, for example, one third of the power supply voltage. The embodiment of the present disclosure uses the voltage method to determine and set the preset voltage in advance, which minimizes the motor loss and does not require the injection of a voltage vector to reach the magnetic saturation state of the motor stator inductance. The quietness at the start-up time is significantly improved.

[0086] The presently disclosed embodiment does not limit the specific size of the preset angle, and those skilled in the art may set it according to actual conditions and needs. In one possible implementation, the preset angle is 180°.

[0087] In a possible implementation manner, injecting the driving signal and the detection signal respectively according to the position determined by the position detection module 60 and setting the duration thereof may include:

[0088] When the angle of the rotor of the three-phase motor 10 relative to the stator is 0°, injecting the drive signal for a preset time length;

[0089] When the angle of the rotor of the three-phase motor 10 relative to the stator is 180°, the detection signal is injected for a preset time period.

[0090] The disclosed embodiment improves the accuracy of detecting the winding direction of the motor by injecting the drive signal for a preset time length when the angle of the rotor of the three-phase motor 10 relative to the stator is 0°, and injecting the detection signal for a preset time length when the angle of the rotor of the three-phase motor 10 relative to the stator is 180°.

[0091] The embodiments of the present disclosure do not limit the specific implementation of the position detection module. Those skilled in the art may implement it in a suitable manner according to actual conditions and needs. In a possible implementation, the position detection module 60 includes a Hall sensor.

[0092] The driving signal and the detection signal are exemplarily introduced below.

[0093] In a possible implementation, the drive signal includes at least one of a first drive signal, a second drive signal, a third drive signal, a fourth drive signal, a fifth drive signal, and a sixth drive signal, the detection signal and the drive signal are opposite signals, and the corresponding relationship between the drive signal, the detection signal and the corresponding non-conducting phase is shown in Table 1.

[0094] Table 1

[0095]

[0096] Among them, A, B, and C respectively represent the phases of a three-phase motor (which can be recorded as the first phase or phase A, the second phase or phase B, and the third phase or phase C), "up" means that the transistor of the upper bridge arm is turned on, and "down" means that the transistor of the lower bridge arm is turned on. By way of example, A up and C down means that the transistor of the upper bridge arm of the first bridge arm corresponding to A is turned on, and the transistor of the lower bridge arm of the third bridge arm corresponding to C is turned on. An exemplary introduction is given below.

[0097] In one example, if Figure 2 As shown in Table 1, the first drive signal (A up, C down) is used to drive the transistor of the upper bridge arm of the first bridge arm to turn on, and the transistor of the lower bridge arm of the third bridge arm to turn on. The non-conducting phase corresponding to the time period in which the first drive signal acts is the second phase. Correspondingly, the first detection signal (C up, A down) corresponding to the first drive signal is used to drive the transistor of the upper bridge arm of the third bridge arm to turn on, and the transistor of the lower bridge arm of the first bridge arm to turn on. The non-conducting phase corresponding to the time period in which the fourth drive signal acts is the second phase.

[0098] In one example, if Figure 2 As shown in Table 1, the second drive signal (B up, C down) is used to drive the transistor of the upper bridge arm of the second bridge arm to turn on, and the transistor of the lower bridge arm of the third bridge arm to turn on. The non-conducting phase corresponding to the time period in which the second drive signal acts is the first phase. Correspondingly, the second detection signal (C up, B down) corresponding to the second drive signal is used to drive the transistor of the upper bridge arm of the third bridge arm to turn on, and the transistor of the lower bridge arm of the second bridge arm to turn on. The non-conducting phase corresponding to the time period in which the fifth drive signal acts is the first phase.

[0099] In one example, if Figure 2As shown in Table 1, the third drive signal (B up and A down) is used to drive the transistor of the upper bridge arm of the second bridge arm to turn on, and the transistor of the lower bridge arm of the first bridge arm to turn on. The non-conducting phase corresponding to the time period in which the third drive signal acts is the third phase. Correspondingly, the third detection signal (A up and B down) corresponding to the third drive signal is used to drive the transistor of the upper bridge arm of the first bridge arm to turn on, and the transistor of the lower bridge arm of the second bridge arm to turn on. The non-conducting phase corresponding to the time period in which the sixth drive signal acts is the third phase.

[0100] In one example, if Figure 2 As shown in Table 1, the fourth drive signal (C up and A down) is used to drive the transistor of the upper bridge arm of the third bridge arm to turn on, and the transistor of the lower bridge arm of the first bridge arm to turn on, and the non-conducting phase corresponding to the time period in which the fourth drive signal acts is the second phase. Correspondingly, the fourth detection signal (A up and C down) corresponding to the fourth drive signal is used to drive the transistor of the upper bridge arm of the first bridge arm to turn on, and the transistor of the lower bridge arm of the third bridge arm to turn on, and the non-conducting phase corresponding to the time period in which the first drive signal acts is the second phase;

[0101] In one example, if Figure 2 As shown in Table 1, the fifth drive signal (C up and B down) is used to drive the transistor of the upper bridge arm of the third bridge arm to turn on, and the transistor of the lower bridge arm of the second bridge arm to turn on, and the non-conducting phase corresponding to the time period in which the fifth drive signal acts is the first phase. Correspondingly, the fifth detection signal (B up and C down) corresponding to the fifth drive signal is used to drive the transistor of the upper bridge arm of the second bridge arm to turn on, and the transistor of the lower bridge arm of the third bridge arm to turn on, and the non-conducting phase corresponding to the time period in which the second drive signal acts is the first phase;

[0102] In one example, if Figure 2 As shown in Table 1, the sixth drive signal (A up and B down) is used to drive the transistor of the upper bridge arm of the first bridge arm to turn on, and the transistor of the lower bridge arm of the second bridge arm to turn on, and the non-conducting phase corresponding to the time period during which the sixth drive signal acts is the third phase. Correspondingly, the sixth detection signal (B up and A down) corresponding to the sixth drive signal is used to drive the transistor of the upper bridge arm of the second bridge arm to turn on, and the transistor of the lower bridge arm of the first bridge arm to turn on, and the non-conducting phase corresponding to the time period during which the third drive signal acts is the third phase.

[0103] The principle of determining the winding direction in the embodiment of the present disclosure is exemplarily introduced below.

[0104] See also Figure 3a and Figure 3b , Figure 3a A schematic diagram showing a magnetization curve of a stator core of a three-phase motor according to an embodiment of the present disclosure is shown, Figure 3b A schematic diagram showing a magnetization curve BH and a magnetic permeability curve μ-H of a ferromagnetic material used in a three-phase motor according to an embodiment of the present disclosure is shown.

[0105] In one example, in order to maximize the use of core materials, the no-load operating point of the motor is selected where the rising slope of the magnetization curve is small, such as Figure 3b Point A in .

[0106] The rated operating point of the motor core is not at its maximum magnetic permeability, but on the right side of the maximum magnetic permeability, such as Figure 3b As shown in point A. When current is passed through the stator armature winding, the armature reaction caused by the armature magnetic potential will cause the operating point to shift, resulting in a change in magnetic permeability.

[0107] In one example, the inductance of the motor stator armature winding can be obtained by Equation 1:

[0108]

[0109] Further, we can get formula 2:

[0110]

[0111] According to Ampere's circuit theorem, Formula 2 can be transformed into Formula 3:

[0112]

[0113] Among them, ψ S Represents the stator armature flux, N S represents the number of turns of the stator armature winding, S represents the cross-sectional area of ​​the magnetic circuit, i S represents the stator armature winding current, L is the magnetic path length, R mψ It represents the magnetic resistance of the main magnetic circuit of the motor, which is mainly composed of two parts: the iron core magnetic resistance and the air gap magnetic resistance. B represents the magnetic induction intensity.

[0114] The magnetic resistance of the motor main magnetic circuit can be obtained by formula 4:

[0115]

[0116] Among them, R Fe Represents the core magnetic resistance, R σ Represents the air gap reluctance, L Fe Indicates the core magnetic path length, μ Fe Indicates the core magnetic permeability, L σ Indicates the air gap magnetic path length, μ σ Represents the air gap permeability.

[0117] In one example, for a selected motor, the number of turns of the stator armature winding is N Sis a constant, and for surface mounted brushless DC motors, the air gap length L σ is certain, the air gap permeability μ σ unchanged, then the air gap magnetic resistance R σ is constant; for the core reluctance with a longer magnetic circuit, the magnetic potential generated by the armature winding will cause the magnetic field intensity H to change, resulting in different magnetic permeabilities μ for the magnetization and demagnetization effects. Fe .

[0118] In one example, when the absolute value of the angle between the magnetic potential generated by the armature winding and the permanent magnet magnetic potential is less than 90°, the component of the armature magnetic potential on the d-axis is positive, which will lead to a magnetization effect. Figure 3b It can be seen that the magnetic permeability of the core will become smaller, thereby reducing the stator inductance; when the absolute value of the angle between the magnetic potential generated by the armature winding and the permanent magnet magnetic potential is greater than 90°, such as Figure 3b As shown, the component of the armature magnetic potential on the d-axis is negative, which will cause a demagnetization effect, the magnetic permeability of the core will increase, and thus the stator inductance will increase.

[0119] See also Figure 3c , Figure 3c A schematic diagram showing the relationship between the electronic inductance of a three-phase motor according to an embodiment of the present disclosure and the change in the angle between the magnetic potential generated by the armature winding and the permanent magnet magnetic potential.

[0120] Figure 3c The middle ordinate represents the change of stator inductance with the change of the angle of the rotor relative to the stator. When the angle of the rotor relative to the stator is less than 90°, the stator inductance is greater than the original inductance, that is, the stator inductance is more than 100% of the original inductance.

[0121] In one example, if Figure 3c As shown, the smaller the angle between the armature magnetic potential and the permanent magnet magnetic potential, the greater the magnetization effect and the smaller the corresponding stator winding inductance.

[0122] In one example, the motor phase voltage of a brushless DC motor may be as shown in Equation 5:

[0123]

[0124] Among them, u a,b,c represents phase voltage, R represents phase resistance, L S represents the stator phase inductance, i a,b,c Represents the phase current, e a,b,c Indicates opposite electric potential.

[0125] In one example, when the motor is at rest or at a very low speed, the back EMF e a,b,c Very small, can be ignored; the phase resistance of the motor is usually very small, and the phase containing resistance can also be ignored. In this case, the above formula 5 can be simplified to:

[0126]

[0127] From formula 6, we can see that when the motor speed is very low, the phase voltage is approximately proportional to the stator phase inductance. When the speed is very high, the voltage sampled is considered to be the back-EMF phase voltage caused by the speed and the voltage drop on the inductance and resistance is ignored. At low speed, it is just the opposite, because the speed is very low, the back-EMF is related to the speed e=C e φn, where C is a constant, φ is the magnetic flux of the permanent magnet and can also be considered constant. Therefore, the back electromotive force of the motor is directly positively correlated with the speed. For this reason, when the motor starts, the current is large, the speed is too low and the back electromotive force is too small. The voltage on the voltage basically acts on the inductance and resistance of the motor, so the starting current is large.

[0128] From the above analysis, we can see that the stator inductance of the brushless DC motor is not always constant. The stator inductance will increase with the continuous increase of the stator current (such as Figure 3a As shown in Figure 2, when the stator current reaches a certain value, the stator inductance will reach saturation; at the same time, the rotor permanent magnet also has a great influence on the stator inductance, such as Figure 3c shown.

[0129] Therefore, when the motor is stationary, the angle between the armature magnetic potential (stator magnetic field) and the permanent magnet magnetic potential will determine whether the armature reaction has a demagnetizing or magnetizing effect. When the angle between the stator magnetic field and the rotor permanent magnet magnetic field is less than 90°, the rotor permanent magnet has a magnetizing effect on the stator magnetic field. When the angle between the stator magnetic field and the rotor permanent magnet magnetic field is greater than 90°, the rotor permanent magnet has a demagnetizing effect on the stator magnetic field. The demagnetizing and magnetizing effects will affect the saturation degree of the stator core, and the difference will be reflected in the stator inductance. The difference in stator inductance will lead to the difference in the magnitude of the induced voltage of the third non-conducting phase caused by only two phases being turned on. The smaller the angle between the armature magnetic potential and the permanent magnet magnetic potential, the greater the magnetizing effect, and the smaller the corresponding stator winding inductance. Therefore, the embodiment of the present disclosure injects a driving signal and a detection signal for preset durations respectively according to the position determined by the position detection module, wherein the position phase difference between the driving signal and the detection signal is a preset angle, and the driving signal and the detection signal are opposite signals. The first voltage of the non-conducting phase of the three-phase motor when the driving signal is applied, and the second voltage of the non-conducting phase of the three-phase motor when the detection signal is applied are detected, thereby determining the winding direction of the motor according to the first voltage and the second voltage. The embodiment of the present disclosure can realize the identification of the winding direction during the power-on initialization stage of the motor.

[0130] The embodiments of the present disclosure have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A motor winding direction detection device, characterized in that: The device includes a three-phase motor, a three-phase full-bridge inverter, a position detection module, a voltage detection module, a drive module and a winding direction judgment module. The three-phase full-bridge inverter comprises a first bridge arm, a second bridge arm and a third bridge arm, each bridge arm comprises an upper bridge arm and a lower bridge arm, and the upper bridge arm and the lower bridge arm of each bridge arm are provided with a transistor, and the three-phase full-bridge inverter is used to drive the three-phase motor, and the first bridge arm, the second bridge arm and the third bridge arm correspond to the first phase, the second phase and the third phase of the three-phase motor respectively; The position detection module is used to determine the position of the rotor relative to the stator in the three-phase motor; The driving module is connected to each transistor of the three-phase full-bridge inverter, and is used to inject a driving signal and a detection signal for a preset duration according to the position determined by the position detection module, wherein the positions of the driving signal and the detection signal differ by a preset angle, and the driving signal and the detection signal are opposite signals; The voltage detection module is connected between the upper bridge arm and the lower bridge arm of each bridge arm of the three-phase full-bridge inverter, and is used to detect the first voltage of the non-conducting phase of the three-phase motor when the driving signal is applied, and the second voltage of the non-conducting phase of the three-phase motor when the detection signal is applied; The winding direction determination module is connected to the voltage detection module and is used to determine the winding direction of the motor according to the first voltage and the second voltage. The step of determining the winding direction of the motor according to the first voltage and the second voltage includes: When the first voltage is less than the second voltage, determining that the winding direction of the motor is clockwise; or When the first voltage is greater than or equal to the second voltage, it is determined that the winding direction of the motor is counterclockwise.

2. The detection device according to claim 1, characterized in that: The step of determining the winding direction of the motor according to the first voltage and the second voltage includes: Respectively determine a first time duration and a second time duration for the first voltage and the second voltage to reach a preset voltage, wherein the first time duration and the second time duration are both shorter than the preset time duration; When the first time length is less than the second time length, determining that the winding direction of the motor is clockwise; or When the first time length is greater than or equal to the second time length, it is determined that the winding direction of the motor is counterclockwise.

3. The detection device according to any one of claims 1 to 2, characterized in that: The preset angle is 180°.

4. The detection device according to any one of claims 1 to 2, characterized in that: The step of injecting a driving signal and a detection signal respectively for a preset time period according to the position determined by the position detection module comprises: When the angle of the rotor of the three-phase motor relative to the stator is 0°, injecting the drive signal for a preset time length; When the angle of the rotor of the three-phase motor relative to the stator is 180°, the detection signal is injected for a preset time period.

5. The device according to claim 1, characterized in that The position detection module includes a Hall sensor.

6. The device according to claim 1, characterized in that The driving signal includes at least one of a first driving signal, a second driving signal, a third driving signal, a fourth driving signal, a fifth driving signal, and a sixth driving signal, wherein: The first driving signal is used to drive the transistor of the upper bridge arm of the first bridge arm to be turned on and the transistor of the lower bridge arm of the third bridge arm to be turned on, and the non-conducting phase corresponding to the time period during which the first driving signal acts is the second phase; The second driving signal is used to drive the transistor of the upper bridge arm of the second bridge arm to be turned on and the transistor of the lower bridge arm of the third bridge arm to be turned on, and the non-conducting phase corresponding to the time period during which the second driving signal acts is the first phase; The third driving signal is used to drive the transistor of the upper bridge arm of the second bridge arm to be turned on and the transistor of the lower bridge arm of the first bridge arm to be turned on, and the non-conducting phase corresponding to the time period during which the third driving signal acts is the third phase; The fourth driving signal is used to drive the transistor of the upper bridge arm of the third bridge arm to be turned on and the transistor of the lower bridge arm of the first bridge arm to be turned on, and the non-conducting phase corresponding to the time period during which the fourth driving signal acts is the second phase; The fifth driving signal is used to drive the transistor of the upper bridge arm of the third bridge arm to be turned on and the transistor of the lower bridge arm of the second bridge arm to be turned on, and the non-conducting phase corresponding to the time period during which the fifth driving signal acts is the first phase; The sixth driving signal is used to drive the transistor of the upper bridge arm of the first bridge arm to turn on and the transistor of the lower bridge arm of the second bridge arm to turn on. The non-conducting phase corresponding to the time period during which the sixth driving signal acts is the third phase.

7. The device according to claim 1, characterized in that The voltage detection module includes a first voltage detection unit, a second voltage detection unit and a third voltage detection unit, which are respectively connected between the upper bridge arm and the lower bridge arm of each phase of the three-phase full-bridge inverter, wherein each voltage detection unit includes a first detection resistor and a second detection resistor, The first end of the first detection resistor is connected between the upper bridge arm and the lower bridge arm of the corresponding phase, and the second end of the first detection resistor is connected to the first end of the second detection resistor, for outputting a detection voltage; A second terminal of the second detection resistor is grounded.

8. A drive assembly, characterized in that: The driving assembly includes a motor winding direction detection device as described in any one of claims 1-7.

9. An electric tool, characterized in that: The electric tool comprises the drive assembly according to claim 8.

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