Torque-stable two-phase brushless direct current motor and control method thereof

Abstract

This invention discloses a torque-stable two-phase brushless DC motor and its control method. The two-phase brushless DC motor includes a stator and a rotor. The stator includes a stator core and 4*n stator windings surrounding the stator core. The rotor includes a rotor core and 6*n permanent magnet poles surrounding the rotor core, where n is a positive integer, and adjacent permanent magnet poles have opposite polarities. This invention features high stator winding utilization efficiency, reduces the weight of the brushless DC motor, and exhibits low torque ripple, making it suitable for applications requiring continuous power output.

Description

Technical Field

[0001] This invention relates to the field of brushless DC motor technology, and in particular to a torque-stable two-phase brushless DC motor and its control method. Background Technology

[0002] Brushless DC motors have a wide range of applications across various industries, especially multi-rotor drones, which almost exclusively use brushless DC motors as their power source. The most commonly used brushless DC motor is the three-phase brushless DC motor.

[0003] Existing three-phase brushless DC motors consist of a basic unit composed of three-phase stator windings and two permanent magnet poles, i.e., a 3:2 ratio of stator windings to permanent magnet poles. During operation, the electronic speed controller simulates the generation of three-phase alternating current, which generates an alternating magnetic field through the stator windings. This magnetic field interacts with the permanent magnet poles, thus converting electrical energy into mechanical rotational energy. However, this design has the following drawbacks: the magnetic field itself only has two poles, so at any given time, one of the three stator windings will always be inactive. The utilization efficiency of the windings is no higher than 67%. Since the weight of the brushless DC motor mainly comes from the stator core and the stator windings wound around it, the low utilization efficiency of the stator windings significantly reduces the motor's power-to-weight ratio.

[0004] There is also a technical solution for two-phase brushless DC motors with the same number of stator windings and permanent magnet poles. Although the stator windings have high utilization efficiency, they have the following drawbacks: large torque ripple. For each step angle, the torque reaches its maximum at the beginning of the step angle and approaches zero at the end of the step angle. This is not suitable for applications such as multi-rotor drones that require continuous power output. Summary of the Invention

[0005] In order to solve the above-mentioned technical problems, the present invention provides a two-phase brushless DC motor with stable torque and its control method, which has high utilization efficiency of stator winding, reduces the weight of brushless DC motor, and has small torque ripple.

[0006] To solve the above problems, the present invention adopts the following technical solution:

[0007] The present invention discloses a torque-stable two-phase brushless DC motor, comprising a stator and a rotor. The stator includes a stator core and 4*n stator windings surrounding the stator core. The rotor includes a rotor core and 6*n permanent magnet poles surrounding the rotor core, where n is a positive integer and the polarities of adjacent permanent magnet poles are opposite.

[0008] In this scheme, every four sequentially adjacent stator windings form a group. The electronic speed controller controls the current phase difference between adjacent stator windings in each group to be 90°. Combined with a specific combination of a 4:6 ratio of stator windings to permanent magnet poles, when the torque generated by one stator winding decreases, the torque generated by the adjacent stator winding increases. The torques generated by any two adjacent stator windings are in a complementary working state, thereby generating a stable torque output. This solves the technical problem of large torque ripple in other two-phase brushless DC motors and is suitable for applications with continuous power output.

[0009] In this design, the ratio of stator windings to permanent magnet poles is 4:6, which reduces the number of stator windings compared to traditional three-phase brushless DC motors. The stator windings in this design are always in normal operating condition, improving their utilization efficiency. While the number of stator windings used in this design is only two-thirds that of traditional three-phase brushless DC motors, and the number of permanent magnet poles is correspondingly increased, the permanent magnet poles are much lighter than the stator windings, thus reducing the weight of the brushless DC motor and improving its power-to-weight ratio.

[0010] Preferably, the 4*n stator windings are arranged in a circle and are equally spaced along the circle, and the 6*n permanent magnet poles are arranged in a circle and are equally spaced along the circle.

[0011] Preferably, the rotor core is disposed inside the stator core, the permanent magnet poles are disposed on the outer side wall of the rotor core, and the stator windings are disposed on the inner side wall of the stator core; or, the stator core is disposed inside the rotor core, the stator windings are disposed on the outer side wall of the stator core, and the permanent magnet poles are disposed on the inner side wall of the rotor core.

[0012] The rotor on the outside of the stator forms an external rotor brushless DC motor, and the rotor on the inside of the stator forms an internal rotor brushless DC motor.

[0013] Preferably, the 4*n stator windings are divided into n groups, and each group of stator windings includes 4 stator windings that are sequentially adjacent. The 4 stator windings that are sequentially adjacent are named stator winding A, stator winding B, stator winding C, and stator winding D in a clockwise direction. All stator windings A are connected in series in a clockwise direction to form a first series circuit, all stator windings B are connected in series in a clockwise direction to form a second series circuit, all stator windings C are connected in series in a clockwise direction to form a third series circuit, and all stator windings D are connected in series in a clockwise direction to form a fourth series circuit.

[0014] The stator windings have a coil start end and a coil end. All stator windings A are numbered sequentially as 1, 2, 3…n in a clockwise direction, where 1≤i≤n-1. The coil end of stator winding i is connected in series with the coil start end of stator winding i+1 to form the first series circuit. Similarly, stator windings B, C, and D are connected to obtain the second, third, and fourth series circuits, respectively.

[0015] Since the current phase difference between adjacent stator windings is 90°, the phase difference between two stator windings separated by one position (such as stator winding A and stator winding C, stator winding B and stator winding D) is 0° or 180°. There are several ways to combine two stator windings separated by one position into a magnetic pole pair.

[0016] Preferably, all stator windings are wound in the same direction, the first series circuit and the third series circuit are connected in reverse parallel to form a first parallel circuit, and the second series circuit and the fourth series circuit are connected in reverse parallel to form a second parallel circuit.

[0017] Connect the starting end of stator winding A (numbered 1) in the first series circuit to the ending end of stator winding C (numbered n) in the third series circuit, and connect the ending end of stator winding A (numbered n) in the first series circuit to the starting end of stator winding C (numbered 1) in the third series circuit, thus forming a first parallel circuit. Connect the starting end of stator winding B (numbered 1) in the second series circuit to the ending end of stator winding D (numbered n) in the fourth series circuit, and connect the ending end of stator winding B (numbered n) in the second series circuit to the starting end of stator winding D (numbered 1) in the fourth series circuit, thus forming a second parallel circuit.

[0018] After the first series circuit and the third series circuit are connected in reverse parallel to form the first parallel circuit, they can share the same control loop of the electronic speed controller. Since the current directions in stator winding A and stator winding C are opposite and the winding directions are the same, the phase difference between the currents in stator winding A and stator winding C is 180°, and their electromagnetic polarities are exactly opposite at the same time. After the second series circuit and the fourth series circuit are connected in reverse parallel to form the second parallel circuit, they can share the same control loop of the electronic speed controller. Since the current directions in stator winding B and stator winding D are opposite and the winding directions are the same, the phase difference between the currents in stator winding B and stator winding D is 180°, and their electromagnetic polarities are exactly opposite at the same time.

[0019] Preferably, the torque-stable two-phase brushless DC motor further includes an electronic speed controller, wherein the two ends of the first parallel circuit are electrically connected to the first input terminal and the first output terminal of the electronic speed controller, respectively, and the two ends of the second parallel circuit are electrically connected to the second input terminal and the second output terminal of the electronic speed controller, respectively.

[0020] Preferably, the winding directions of stator winding A and stator winding B are the same, the winding directions of stator winding C and stator winding D are the same, the winding directions of stator winding A and stator winding C are opposite, the winding directions of stator winding B and stator winding D are opposite, the first series circuit and the third series circuit are connected in a forward direction to form a fifth series circuit, and the second series circuit and the fourth series circuit are connected in a forward direction to form a sixth series circuit.

[0021] After the first and third series circuits are connected in the same direction to form the fifth series circuit, they can share the same control loop of the electronic speed controller. Since the winding directions of stator A and stator C are opposite and the current directions are the same, the electromagnetic polarities of stator A and stator C are exactly opposite at the same time. After the second and fourth series circuits are connected in the same direction to form the sixth series circuit, they can share the same control loop of the electronic speed controller. Since the winding directions of stator B and stator D are opposite and the current directions are the same, the electromagnetic polarities of stator B and stator D are exactly opposite at the same time.

[0022] Preferably, the torque-stable two-phase brushless DC motor further includes an electronic speed controller, with the two ends of the fifth series circuit electrically connected to the first input terminal and the first output terminal of the electronic speed controller, respectively, and the two ends of the sixth series circuit electrically connected to the second input terminal and the second output terminal of the electronic speed controller, respectively.

[0023] Preferably, the stator core is provided with a detection component for detecting the rotor position, the detection component including two or more Hall sensors arranged along the circumferential direction.

[0024] The present invention provides a control method for a torque-stable two-phase brushless DC motor, used in the aforementioned torque-stable two-phase brushless DC motor, comprising the following steps: using an electronic speed controller to control the input current of stator windings A, B, C, and D, and controlling the current phase difference between adjacent stator windings in each group of stator windings to be 90°.

[0025] The control current of the stator winding controlled by the electronic speed controller is a sine wave or a square wave.

[0026] The beneficial effects of this invention are: high utilization efficiency of the stator winding, reduced weight of the brushless DC motor, improved power-to-weight ratio, and low torque ripple, making it suitable for applications with continuous power output. Attached Figure Description

[0027] Figure 1 This is a structural schematic diagram of Example 1;

[0028] Figure 2 These are the current waveforms of each stator winding in Example 1;

[0029] Figure 3 This is a structural schematic diagram of Example 2;

[0030] Figure 4 This is a schematic diagram of an example structure of Embodiment 2.

[0031] In the diagram: 1. Stator core, 2. Stator winding, 3. Rotor core, 4. Permanent magnet pole. Detailed Implementation

[0032] The technical solution of the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings.

[0033] Example 1: A torque-stable two-phase brushless DC motor according to this example, such as... Figure 1 As shown, it includes a stator and a rotor. The stator includes a stator core 1 and 4*n stator windings 2 surrounding the stator core 1. The 4*n stator windings 2 are arranged in a circle and are equally spaced along the circle. The rotor includes a rotor core 3 and 6*n permanent magnet poles 4 surrounding the rotor core 3. n is a positive integer. The 6*n permanent magnet poles 4 are arranged in a circle and are equally spaced along the circle. The polarities of adjacent permanent magnet poles 4 are opposite.

[0034] The rotor core 3 is located inside the stator core 1, the permanent magnet pole 4 is located on the outer side wall of the rotor core 3, the stator winding 2 is located on the inner side wall of the stator core 1, and the stator core 3 is provided with a detection component for detecting the rotor position, which includes two or more Hall sensors arranged along the circumferential direction.

[0035] In this design, the rotor forms an internal rotor brushless DC motor inside the stator. Every four sequentially adjacent stator windings constitute a group. The electronic speed controller controls the current phase difference between adjacent stator windings in each group to be 90°. The ideal waveform for the control current is a sine wave, but a square wave (trapezoidal wave) is also acceptable considering cost factors. The permanent magnet poles are arranged with alternating N and S polarities. Combined with a specific combination where the ratio of the number of stator windings to the number of permanent magnet poles is 4:6, when the torque generated by one stator winding decreases, the torque generated by the adjacent stator winding increases, and vice versa. The torques generated by any two adjacent stator windings are in a complementary working state, thereby producing a stable torque output. This solves the technical problem of large torque ripple in other two-phase brushless DC motors and is suitable for applications with continuous power output.

[0036] Taking a two-phase brushless DC motor with 4 stator windings and 6 permanent magnet poles as an example, such as Figure 1 As shown, the four stator windings are labeled A, B, C, and D in clockwise order. The winding directions of all four stator windings are consistent. Figure 1 This describes the state of a two-phase brushless DC motor at time t, and the currents in the four stator windings are as follows: Figure 2 As shown, the current phase difference between adjacent stator windings is 90°, the current phase difference between stator winding A and stator winding C is 180°, and the current phase difference between stator winding B and stator winding D is 180°. At time t, the currents in stator windings A and C reach their maximum values, and stator windings A and C are respectively located at the middle positions of the two permanent magnet poles, thus contributing the most to the torque. The currents in stator windings B and D are exactly 0, and stator windings B and D are respectively at their... For a single permanent magnet pole, its contribution to torque is zero. As the rotor continues to rotate, the contributions of stator windings A and C to torque gradually decrease, while the contributions of stator windings B and D to torque gradually increase. When the contributions of stator windings B and D to torque reach their maximum, the contributions of stator windings A and C to torque just decrease to zero. The torques generated by the two adjacent stator windings are in a complementary working state, reducing torque pulsation and thus producing a stable torque output.

[0037] In this design, the ratio of stator windings to permanent magnet poles is 4:6, which reduces the number of stator windings compared to traditional three-phase brushless DC motors. The stator windings in this design are always in normal operating condition, increasing their efficiency by 50%. Although the number of stator windings used in this design is only two-thirds that of traditional three-phase brushless DC motors, and the number of permanent magnet poles is correspondingly increased, the permanent magnet poles are much lighter than the stator windings, thus reducing the weight of the brushless DC motor and improving its power-to-weight ratio.

[0038] There are two ways to connect the stator windings:

[0039] Method (1):

[0040] The 4*n stator windings are divided into n groups. Each group of stator windings includes 4 stator windings that are connected in a clockwise direction. The 4 stator windings are named A stator winding, B stator winding, C stator winding, and D stator winding in a clockwise direction. All A stator windings are connected in series in a clockwise direction to form the first series circuit. All B stator windings are connected in series in a clockwise direction to form the second series circuit. All C stator windings are connected in series in a clockwise direction to form the third series circuit. All D stator windings are connected in series in a clockwise direction to form the fourth series circuit. The winding direction of all stator windings is the same. The first series circuit and the third series circuit are connected in parallel in a counter-clockwise direction to form the first parallel circuit. The second series circuit and the fourth series circuit are connected in parallel in a counter-clockwise direction to form the second parallel circuit.

[0041] A torque-stable two-phase brushless DC motor also includes an electronic speed controller. The two ends of the first parallel circuit are electrically connected to the first input terminal and the first output terminal of the electronic speed controller, respectively, and the two ends of the second parallel circuit are electrically connected to the second input terminal and the second output terminal of the electronic speed controller, respectively.

[0042] The stator windings have a coil start end and a coil end. All stator windings A are numbered sequentially as 1, 2, 3…n in a clockwise direction, where 1≤i≤n-1. The coil end of stator winding i is connected in series with the coil start end of stator winding i+1 to form the first series circuit. Similarly, stator windings B, C, and D are connected to obtain the second, third, and fourth series circuits, respectively.

[0043] Connect the starting end of stator winding A (numbered 1) in the first series circuit to the ending end of stator winding C (numbered n) in the third series circuit, and connect the ending end of stator winding A (numbered n) in the first series circuit to the starting end of stator winding C (numbered 1) in the third series circuit, thus forming a first parallel circuit. Connect the starting end of stator winding B (numbered 1) in the second series circuit to the ending end of stator winding D (numbered n) in the fourth series circuit, and connect the ending end of stator winding B (numbered n) in the second series circuit to the starting end of stator winding D (numbered 1) in the fourth series circuit, thus forming a second parallel circuit.

[0044] After the first series circuit and the third series circuit are connected in reverse parallel to form the first parallel circuit, they can share the same control loop of the electronic speed controller. Since the current directions in stator winding A and stator winding C are opposite and the winding directions are the same, the phase difference between the currents in stator winding A and stator winding C is 180°, and their electromagnetic polarities are exactly opposite at the same time. After the second series circuit and the fourth series circuit are connected in reverse parallel to form the second parallel circuit, they can share the same control loop of the electronic speed controller. Since the current directions in stator winding B and stator winding D are opposite and the winding directions are the same, the phase difference between the currents in stator winding B and stator winding D is 180°, and their electromagnetic polarities are exactly opposite at the same time.

[0045] Method (2):

[0046] The 4*n stator windings are divided into n groups. Each group of stator windings includes 4 consecutive stator windings. The 4 consecutive stator windings are named A stator winding, B stator winding, C stator winding, and D stator winding in a clockwise direction. All A stator windings are connected in series in the first series circuit, all B stator windings are connected in the second series circuit, all C stator windings are connected in the third series circuit, and all D stator windings are connected in the fourth series circuit. The winding directions of A stator winding and B stator winding are the same, the winding directions of C stator winding and D stator winding are the same, the winding directions of A stator winding and C stator winding are opposite, the winding directions of B stator winding and D stator winding are opposite, the first series circuit and the third series circuit are connected in the fifth series circuit in the first direction, and the second series circuit and the fourth series circuit are connected in the sixth series circuit in the first direction.

[0047] A torque-stable two-phase brushless DC motor also includes an electronic speed controller. The two ends of the fifth series circuit are electrically connected to the first input terminal and the first output terminal of the electronic speed controller, respectively, and the two ends of the sixth series circuit are electrically connected to the second input terminal and the second output terminal of the electronic speed controller, respectively.

[0048] The stator windings have a coil start end and a coil end. All stator windings A are numbered sequentially as 1, 2, 3…n in a clockwise direction, where 1≤i≤n-1. The coil end of stator winding i is connected in series with the coil start end of stator winding i+1 to form the first series circuit. Similarly, stator windings B, C, and D are connected to obtain the second, third, and fourth series circuits, respectively.

[0049] Connect the coil termination end of stator winding A, numbered n in the first series circuit, to the coil start end of stator winding C, numbered 1 in the third series circuit to form the fifth series circuit. Connect the coil termination end of stator winding B, numbered n in the second series circuit, to the coil start end of stator winding D, numbered 1 in the fourth series circuit to form the sixth series circuit.

[0050] After the first and third series circuits are connected in the same direction to form the fifth series circuit, they can share the same control loop of the electronic speed controller. Since the winding directions of stator A and stator C are opposite and the current directions are the same, the electromagnetic polarities of stator A and stator C are exactly opposite at the same time. After the second and fourth series circuits are connected in the same direction to form the sixth series circuit, they can share the same control loop of the electronic speed controller. Since the winding directions of stator B and stator D are opposite and the current directions are the same, the electromagnetic polarities of stator B and stator D are exactly opposite at the same time.

[0051] A two-phase brushless DC motor consisting of 4 stator windings and 6 permanent magnet poles is just a basic combination. In practical applications, it can be expanded proportionally according to requirements to evolve into a series of products with a stator winding to permanent magnet pole ratio of 4:6, such as 8:12, 12:18, 16:24, etc., to adapt to different application requirements.

[0052] This embodiment provides a control method for a torque-stable two-phase brushless DC motor, used in the aforementioned torque-stable two-phase brushless DC motor, comprising the following steps:

[0053] The electronic speed controller controls the stator winding current as a sine wave or a square wave.

[0054] When the two-phase brushless DC motor adopts the stator winding connection method of (1), the control method is as follows: the electronic speed controller controls the current phase difference between the first parallel circuit and the second parallel circuit to be 90°, that is, the current phase difference between stator winding A and stator winding B is 90°, the current phase difference between stator winding B and stator winding C is 90°, the current phase difference between stator winding C and stator winding D is 90°, the current phase difference between stator winding A and stator winding C is 180°, and the current phase difference between stator winding B and stator winding D is 180°.

[0055] When the two-phase brushless DC motor adopts the stator winding connection method of method (2), the control method is as follows: the electronic speed controller controls the current phase difference between the fifth series circuit and the sixth series circuit to be 90°, that is, the current phase difference between stator winding A and stator winding B is 90°, the current phase difference between stator winding B and stator winding C is 90°, the current phase difference between stator winding C and stator winding D is 90°, the current phase difference between stator winding A and stator winding C is 0°, and the current phase difference between stator winding B and stator winding D is 0°.

[0056] Taking a two-phase brushless DC motor with 4 stator windings and 6 permanent magnet poles as an example, such as Figure 1 As shown, the four stator windings are labeled A, B, C, and D in clockwise order. The winding directions of the four stator windings are consistent. The six permanent magnet poles are labeled N-polarity first permanent magnet pole, S-polarity second permanent magnet pole, N-polarity third permanent magnet pole, S-polarity fourth permanent magnet pole, N-polarity fifth permanent magnet pole, and S-polarity sixth permanent magnet pole in clockwise order. Initially, stator winding B is aligned with the S-polarity second permanent magnet pole, and stator winding D... The fifth permanent magnet pole is directly opposite to the N-polarity. Half of stator winding A is aligned with half of the first permanent magnet pole, and the other half of stator winding A is aligned with half of the sixth permanent magnet pole. Half of stator winding C is aligned with half of the third permanent magnet pole, and the other half of stator winding C is aligned with half of the fourth permanent magnet pole. The electronic speed controller controls the current phase difference between adjacent stator windings in each group of stator windings to be 90°. Initially, the currents in stator windings A and C reach their maximum values ​​and are in opposite directions, while the currents in stator windings B and D are 0.

[0057] Example 2: The structure of this example is basically the same as that of Example 1, except that, as Figure 3 As shown, the stator core 1 is located inside the rotor core 3, the stator winding 2 is located on the outer side wall of the stator core 3, and the permanent magnet pole 4 is located on the inner side wall of the rotor core 3.

[0058] In this design, the rotor is located outside the stator, forming an external rotor brushless DC motor.

[0059] Taking a two-phase brushless DC motor with 28 stator windings and 42 permanent magnet poles as an example, the stator is as follows: Figure 4 As shown, the 28 stator windings are divided into 7 groups. Each group of stator windings includes 4 adjacent stator windings in a clockwise direction. The 4 adjacent stator windings are named A stator winding, B stator winding, C stator winding, and D stator winding in a clockwise direction. The rotor, which consists of 42 permanent magnet poles, can directly adopt the rotor of an existing three-phase brushless DC motor, saving development costs.

[0060] This embodiment provides a control method for a torque-stable two-phase brushless DC motor, which is the same as that in Embodiment 1.

Claims

1. A torque-stable two-phase brushless DC motor, comprising a stator and a rotor, characterized in that, The stator includes a stator core (1) and 4*n stator windings (2) surrounding the stator core (1). The rotor includes a rotor core (3) and 6*n permanent magnet poles (4) surrounding the rotor core, where n is a positive integer. The polarities of adjacent permanent magnet poles (4) are opposite. The 4*n stator windings (2) are divided into n groups. Each group of stator windings includes 4 stator windings that are sequentially adjacent. The 4 stator windings that are sequentially adjacent are named A stator winding, B stator winding, C stator winding, and D stator winding in a clockwise direction. All A stator windings are connected in series in a clockwise direction to form a first series circuit. All B stator windings are connected in series in a clockwise direction to form a second series circuit. All C stator windings are connected in series in a clockwise direction to form a third series circuit. All D stator windings are connected in series in a clockwise direction to form a fourth series circuit. The current phase difference between adjacent stator windings in each group of stator windings is 90°. All stator windings (2) have the same winding direction. The first series circuit and the third series circuit are connected in reverse parallel to form the first parallel circuit. The second series circuit and the fourth series circuit are connected in reverse parallel to form the second parallel circuit. Alternatively, the winding directions of stator winding A and stator winding B are the same, the winding directions of stator winding C and stator winding D are the same, the winding directions of stator winding A and stator winding C are opposite, the winding directions of stator winding B and stator winding D are opposite, the first series circuit and the third series circuit are connected in a forward direction to form a fifth series circuit, and the second series circuit and the fourth series circuit are connected in a forward direction to form a sixth series circuit.

2. The torque-stable two-phase brushless DC motor according to claim 1, characterized in that, The 4*n stator windings (2) are arranged in a circle and are equally spaced along the circle, and the 6*n permanent magnet poles (4) are arranged in a circle and are equally spaced along the circle.

3. A torque-stable two-phase brushless DC motor according to claim 1, characterized in that, The rotor core (3) is located inside the stator core (1), the permanent magnet pole (4) is located on the outer side wall of the rotor core (3), and the stator winding (2) is located on the inner side wall of the stator core (1); or, the stator core (1) is located inside the rotor core (3), the stator winding (2) is located on the outer side wall of the stator core (1), and the permanent magnet pole (4) is located on the inner side wall of the rotor core (3).

4. A torque-stable two-phase brushless DC motor according to claim 1, characterized in that, It also includes an electronic speed controller, with the two ends of the first parallel circuit electrically connected to the first input terminal and the first output terminal of the electronic speed controller, respectively, and the two ends of the second parallel circuit electrically connected to the second input terminal and the second output terminal of the electronic speed controller, respectively.

5. A torque-stable two-phase brushless DC motor according to claim 1, characterized in that, It also includes an electronic speed controller, wherein the two ends of the fifth series circuit are electrically connected to the first input terminal and the first output terminal of the electronic speed controller, respectively, and the two ends of the sixth series circuit are electrically connected to the second input terminal and the second output terminal of the electronic speed controller, respectively.

6. A torque-stable two-phase brushless DC motor according to claim 1, 2, or 3, characterized in that, The stator core (1) is provided with a detection component for detecting the rotor position, and the detection component includes two or more Hall sensors arranged along the circumferential direction.

7. A torque-stable two-phase brushless DC motor according to claim 1, characterized in that, The current waveform is a sine wave, square wave, or trapezoidal wave.

8. A control method for a torque-stable two-phase brushless DC motor, used in the torque-stable two-phase brushless DC motor as described in claim 1, characterized in that, Includes the following steps: An electronic speed controller is used to control the input current of stator windings A, B, C, and D, and to control the current phase difference between adjacent stator windings in each group of stator windings to be 90°.

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