Drive circuits and control methods, apparatus and devices for brushless motors.

Abstract

This disclosure provides a drive circuit and control method, apparatus and equipment for a brushless motor relating to the motor drive technology, the brushless motor comprising a stator core including Z groups of teeth spaced apart along the circumferential direction, a rotor having P magnetic ring poles, and X-phase conductors wound around the groups of teeth to form coils, where X≧2 and Z=P×X, wherein in the same phase conductor, the winding direction along the circumferential direction of the coils on two adjacent groups of teeth is opposite, and the X-phase conductors are arranged at intervals of X-1 groups of teeth, and the drive The drive circuit includes X full-bridge circuits, each full-bridge circuit includes two half-bridge circuits connected in parallel between the input terminal and the ground terminal of the drive circuit, each half-bridge circuit includes two switches connected via nodes, the two half-bridge circuits include a first and a second half-bridge circuit, the node of the first half-bridge circuit in the i-th full-bridge circuit is connected to the first terminal of the i-th phase conductor, and the node of the second half-bridge circuit in the i-th full-bridge circuit is connected to the second terminal of the i-th phase conductor.

Description

[Technical Field]

[0001] This disclosure relates to the motor drive technology, particularly to drive circuits and control methods, apparatus and devices for brushless motors. [Background technology]

[0002] DC brushless motors retain the advantages of conventional DC motors while eliminating carbon brushes and slip ring structures, enabling operation at low speeds and high power. Their small size, light weight, good stability, and high efficiency make them highly applicable in fields such as electric servo drives, information processing, transportation, home appliances, consumer electronics, and national defense.

[0003] A relatively common type of DC brushless motor is the single-phase DC brushless motor, which has features such as a small size and easy control.

[0004] Another relatively common type of DC brushless motor is the three-phase DC brushless motor. It has features such as a long lifespan, low noise, flexible drive system, and a mature industrial chain, making it suitable for a wide range of application scenarios and various consumer and military products. Furthermore, due to its wide speed control range, small size, high efficiency, and small steady-state speed error, the three-phase DC brushless motor also has advantages in the field of speed control.

[0005] Three-phase DC brushless motors employ a "UVW" three-phase winding and a corresponding magnet ring layout design. The three-phase winding has two connection methods: star connection and delta connection. Taking the electric motor as an example, the drive program alternately switches the energization of each of the three-phase windings to create a rotating magnetic field, which in turn rotates the rotor with the magnet ring. [Overview of the Initiative] [Means for solving the problem]

[0006] According to one embodiment of the present disclosure, a drive circuit for a brushless motor is provided, the brushless motor comprising a stator core including Z groups of teeth spaced apart along a first circumferential direction; a rotor including a magnetic ring with P poles (where P is even); and X-phase conductors wound around the groups of teeth to form coils, where X≧2 and Z=P×X, wherein in the same phase of the conductor, the winding direction along the second circumferential direction of the groups of teeth of the coils on two adjacent groups of teeth is opposite, and the X-phase conductors are arranged at intervals of X-1 groups of teeth, the drive circuit comprising X full-bridge circuits Each full-bridge circuit includes two half-bridge circuits connected in parallel between the input terminal and the ground terminal of the drive circuit, each half-bridge circuit includes two switches connected via nodes, the two half-bridge circuits include a first half-bridge circuit and a second half-bridge circuit, where the node of the first half-bridge circuit in the i-th full-bridge circuit is configured to be connected to the -th end of the i-th phase conductor, and the node of the second half-bridge circuit in the i-th full-bridge circuit is configured to be connected to the second end of the i-th phase conductor, such that 1 ≤ i ≤ X.

[0007] In some embodiments, N of the X full-bridge circuits are configured to provide N periodically changing drive signals to the N-phase conductors via their respective independent first and second ends within a single control cycle, where 1 ≤ N ≤ X, and the waveform of each drive signal in one cycle includes a first waveform with an intensity greater than 0 and a second waveform with an intensity less than 0.

[0008] In some embodiments, the intensity of the N drive signals within the first period band is continuously non-zero.

[0009] In some embodiments, the time at which the first waveform and the second waveform overlap is the first time, and the intensity of each drive signal during any period other than the first time within one cycle is continuously non-zero.

[0010] In some embodiments, the intensity of each drive signal during the second period within one cycle is continuously 0.

[0011] In some embodiments, the intensity of each drive signal at any time other than the second period band during one cycle is not zero.

[0012] In some embodiments, during a period in which the intensity of any one drive signal in one cycle is not zero, the intensity of the other drive signals among the N drive signals is all zero.

[0013] In some embodiments, the amplitudes of the N drive signals are the same.

[0014] In some embodiments, the first waveform and the second waveform are centrally symmetrical.

[0015] In some embodiments, the waveforms of the N drive signals are all square waves, or the first waveform and the second waveform match a sine function.

[0016] In some embodiments, the brushless motor includes one or more stator cores, the X-phase conductors are sequentially wound around the group of teeth in the order of the first to the X-phase along the first circumferential direction, and the N-phase conductors include an i-th phase conductor and a k-th phase conductor, with a phase difference θ between the drive signal of the i-th phase conductor and the drive signal of the k-th phase conductor. ik It satisfies the following equation,

number

[0017] In some embodiments, the two switches of each half-bridge circuit include a first switch connected to the input end of the drive circuit and a second switch connected to the ground end of the drive circuit. The first switch is one of an n-type metal oxide semiconductor MOSFET and a p-type MOSFET, and the second switch is an n-type MOSFET.

[0018] According to another aspect of the embodiments of the present disclosure, a control method for a drive circuit for a brushless motor described in any one of the above embodiments is provided. The control method includes, within one control period, controlling one switch in the first half-bridge circuit and one switch in the second half-bridge circuit of each of the N full-bridge circuits among the X full-bridge circuits to be turned on, so that the N full-bridge circuits provide N drive signals that periodically change on the N-phase conductors through the respective independent first ends and second ends of the N-phase conductors. Here, 1 ≤ N ≤ X, and the waveform in one period of each drive signal includes a first waveform with an intensity greater than 0 and a second waveform with an intensity less than 0.

[0019] In some embodiments, the method further includes determining the first amplitude of the N-phase conductors and each drive signal based on the target torque of the rotor, and determining the first frequency of each drive signal based on the target rotational speed of the rotor.

[0020] In some embodiments, when the target torque is higher than a first preset torque, N = X.

[0021] In some embodiments, when the target torque is higher than the first preset torque, the first amplitudes of the N driving signals are the same.

[0022] In some embodiments, when the target torque is lower than a second preset torque, N < X, and the first amplitudes of the N driving signals are the same, or N = X, and the first amplitudes of at least two of the N driving signals are different.

[0023] In some embodiments, one set of parameters that meets the requirements of the target rotational speed and the target torque is called from a plurality of sets of parameters, the one set of parameters represents the second frequency and the second amplitude of each driving signal, and based on the one set of parameters, the first frequency and the first amplitude of each driving signal are determined.

[0024] According to another aspect of the embodiments of the present disclosure, there is provided a control device for a drive circuit of a brushless motor according to any one of the above embodiments. The control device controls, within one control cycle, one switch in the first half-bridge circuit and one switch in the second half-bridge circuit of each of the N full-bridge circuits out of the X full-bridge circuits to be turned on, so that the N full-bridge circuits are configured to provide N driving signals that periodically change on the N-phase conductors through the respective independent first ends and second ends of the N-phase conductors. Here, 1 ≤ N ≤ X, and the waveform in one cycle of each driving signal includes a first waveform with an intensity greater than 0 and a second waveform with an intensity less than 0.

[0025] According to yet another embodiment of the embodiments of the present disclosure, a control device for a drive circuit for a brushless motor described in any one of the embodiments is provided, the control device comprising a memory and a processor coupled to the memory, configured to perform the control method described in any one of the embodiments based on instructions stored in the memory.

[0026] According to yet another embodiment of the embodiments of the present disclosure, a drive system for a brushless motor is provided, the drive system comprising a drive circuit for a brushless motor as described in any one embodiment above, and a control device for the drive circuit for a brushless motor as described in any one embodiment above.

[0027] In some embodiments, the X full-bridge circuits are packaged on a single chip.

[0028] In some embodiments, the control device is packaged on the chip.

[0029] According to yet another embodiment of the embodiments of the present disclosure, a device is provided which includes a drive system for a brushless motor as described in any one of the embodiments above, and the brushless motor.

[0030] In the drive circuits for brushless motors according to some embodiments of the present disclosure, the nodes of two half-bridge circuits of each of the X full-bridge circuits are connected to the first and second ends of the corresponding single-phase conductors. In this way, by controlling the respective states of each switch in the drive circuit, the drive circuit can provide N drive signals to the N-phase conductors of the brushless motor according to the driving method for the brushless motor of any one embodiment described above, thereby driving the brushless motor to provide a relatively large torque with a simple control scheme.

[0031] The technical proposal of this disclosure will be described in more detail below with reference to the attached drawings and examples. To more clearly illustrate the embodiments of this disclosure or the prior art, the following briefly introduces the accompanying drawings that may be used in the embodiments or prior art descriptions. Obviously, the accompanying drawings in the following description are only a few embodiments of this disclosure, and a person skilled in the art can obtain other accompanying drawings based on these without expending any creative effort. [Brief explanation of the drawing]

[0032] [Figure 1A] A schematic diagram of the fitting between the stator core and the magnet ring in a brushless motor based on several embodiments of this disclosure is shown. [Figure 1B] A schematic diagram of the structure in which the conductors are wound around the stator core in a brushless motor based on some embodiments of this disclosure is shown. [Figure 2] This is a flowchart of a drive method for a brushless motor in some embodiments of the present disclosure. [Figure 3A] This is a schematic diagram illustrating the operating principle of a brushless motor in some embodiments of the present disclosure. [Figure 3B] This is a schematic diagram illustrating the operating principle of a brushless motor in some embodiments of the present disclosure. [Figure 3C] This is a schematic diagram illustrating the operating principle of a brushless motor in some embodiments of the present disclosure. [Figure 4A] This is a waveform diagram of a drive signal in a cross-current drive system based on some embodiments of the present disclosure. [Figure 4B] This is a waveform diagram of a drive signal in a cross-current drive system based on some other embodiments of the present disclosure. [Figure 5] This is a waveform diagram of a drive signal in a cross-current drive system based on some further embodiments of the present disclosure. [Figure 6A] This is a waveform diagram of a drive signal in an alternating energization drive system based on some embodiments of the present disclosure. [Figure 6B] This is a waveform diagram of a drive signal in an alternating energization drive system based on some other embodiments of the present disclosure. [Figure 6C] This is a waveform diagram of a drive signal in a cross-current drive system based on some further embodiments of the present disclosure. [Figure 6D] This is a waveform diagram of a drive signal in a cross-current drive system based on some further embodiments of the present disclosure. [Figure 6E] This is a schematic diagram showing the structure of a brushless motor based on some embodiments of the present disclosure, in which two stator cores overlap along the axial direction. [Figure 7] This is a flowchart of a drive method for a brushless motor based on some other embodiments of the present disclosure. [Figure 8] This is a schematic diagram of the structure of a drive device for a brushless motor based on some embodiments of the present disclosure. [Figure 9] This is a schematic diagram of the structure of a drive device for a brushless motor based on some other embodiments of the present disclosure. [Figure 10A] This is a schematic diagram of the structure of a drive circuit for a brushless motor based on some embodiments of the present disclosure. [Figure 10B] This is a schematic diagram of the structure of a drive circuit for a brushless motor based on some other embodiments of the present disclosure. [Figure 11] This is a flowchart of a control method for a drive circuit for a brushless motor based on some embodiments of the present disclosure. [Figure 12] This is a flowchart of a control method for a drive circuit for a brushless motor based on some other embodiments of the present disclosure. [Figure 13] This is a schematic diagram of the structure of a control device for a drive circuit for a brushless motor based on some embodiments of the present disclosure. [Figure 14] This is a schematic diagram of the structure of a control device for a drive circuit for a brushless motor based on some other embodiments of the present disclosure. [Figure 15A] This is a schematic circuit diagram of a drive system for a brushless motor based on some embodiments of the present disclosure. [Figure 15B]This is a schematic circuit diagram of a drive system for a brushless motor based on some other embodiments of the present disclosure. [Figure 16] This is a schematic diagram of the structure of a drive circuit for a brushless motor based on some further embodiments of the present disclosure. [Modes for carrying out the invention]

[0033] The following clearly and completely describes the technical concepts in the embodiments of this disclosure, linking them to the accompanying drawings. Clearly, the embodiments described are only a selection of, and not all, embodiments of this disclosure. All other embodiments derived from the embodiments of this disclosure without the creative effort of a person skilled in the art are all within the scope of this disclosure.

[0034] Unless otherwise specified, the relative arrangement of parts and steps, numerical expressions and values ​​described in these embodiments do not limit the scope of this disclosure.

[0035] At the same time, for the sake of clarity, it should be understood that the sizes of the parts shown in the attached drawings are not necessarily in accordance with the actual proportions.

[0036] While techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, such techniques, methods, and apparatus should be considered as part of the specification where appropriate.

[0037] In all the examples presented and discussed here, any specific values ​​should be interpreted as illustrative only and not as limitations. Therefore, other examples of the illustrative embodiments may have different values.

[0038] Furthermore, since the same symbols and characters represent the same items in the following attached drawings, once an item is defined in a drawing, there is no need to examine it further in subsequent attached drawings.

[0039] However, both single-phase DC brushless motors and three-phase DC brushless motors have their own drawbacks.

[0040] Due to the low torque provided by single-phase DC brushless motors, their application scenarios are relatively limited and are generally applied to household appliances with relatively low power requirements.

[0041] While three-phase DC brushless motors can provide relatively high torque, they require the regular switching of two of the "UVW" three-phase windings in six different ways during operation. The drive signals for each phase winding are all related to the drive signals for the other phase windings, making control complex.

[0042] In this regard, this disclosure proposes the following solutions.

[0043] Embodiments of this disclosure provide a driving method for a brushless motor.

[0044] For ease of understanding, we will first describe some embodiments of the brushless motor of this disclosure by linking Figures 1A and 1B. Figure 1A shows a schematic diagram of the fitting between the stator core and the magnet ring in a brushless motor based on some embodiments of this disclosure. Figure 1B shows a schematic diagram of the structure in which the conductor is wound around the stator core in a brushless motor based on some embodiments of this disclosure.

[0045] As shown in Figures 1A and 1B, the brushless motor includes a stator core 1, a rotor 2, and multiphase conductors 3.

[0046] The stator core 1 includes Z (where Z is an integer) groups of teeth 11 spaced apart along the circumferential direction of the stator core 1 (hereinafter referred to as the first circumferential direction for distinction). In some embodiments, referring to Figures 1A and 1B, the stator core 1 further includes a yoke 12, and the groups of teeth 11 are connected to the yoke 12.

[0047] The number of stator cores 1 may be one or more. It should be understood that if a brushless motor includes multiple stator cores 1, the total number of tooth groups 11 Z is the total number of tooth groups 11 installed on all stator cores 1.

[0048] In some embodiments, the stator core 1 includes multiple stator cores superimposed along the axial direction. In this case, the tooth groups of different stator cores are offset from each other.

[0049] Each tooth group 11 may include one or more adjacent teeth 11' along a first circumferential direction. Figure 1B schematically shows that each tooth group 11 in a brushless motor includes one tooth 11'.

[0050] The rotor 2 includes a magnetic ring 21 with P poles, where P is an even number greater than or equal to 2. The rotor 2 may be mounted, for example, coaxially with the stator core 1 and rotatable relative to the stator core 1.

[0051] The magnetic ring 21 contains an equal number of south poles (S) and north poles (N), and the south and north poles are arranged alternately along the first circumferential direction of the stator core 1. In the brushless motor shown in Figure 1A, the number of poles P of the magnetic ring 21 is equal to 4, and in this case, the magnetic poles along the first circumferential direction of the stator core 1 are NSNS in order.

[0052] The number of multiphase wires 3 is represented by X, where X is an integer greater than or equal to 2. For example, X may be equal to 2, 3, or 5. Figures 1A and 1B schematically show the case where X = 2.

[0053] The X-phase conductor 3 is wound around the teeth group 11 to form a coil 31. For conductors 3 of the same phase, the winding direction along the circumferential direction of the teeth group 11 (hereinafter referred to as the second circumferential direction) of two adjacent teeth groups 11 is opposite, and they are arranged with X-1 teeth groups 11 spaced apart. Each phase conductor 3 has independent ends, which are the first end and the second end, respectively.

[0054] To make it easier to understand, in any one phase of a conductor 3, X-1 tooth groups 11 that leave a gap between two adjacent tooth groups 11 and the coil 31 on them are wound around each of the other X-one phase conductors 3 in a one-to-one correspondence.

[0055] For example, stator core 1 may include X stator cores superimposed along the axial direction, with only one-phase conductors wound around the teeth group of each stator core, and different phase conductors wound around the teeth group of different stator cores. In this case, X-1 teeth groups 11 that create a gap between coils 31 on two adjacent teeth groups 11 of the same phase conductor 3 may belong to other X-1 stator cores other than the stator core in which these two teeth groups 11 are located.

[0056] Since the winding directions along the second circumferential direction of the teeth group 11 of two adjacent teeth groups 11 on the same phase conductor 3 are opposite, the directions of the magnetic fields generated by these two adjacent teeth groups 11 are opposite. The coils 31 on two adjacent teeth groups 11 on the same phase conductor 3 can be connected, for example, via a connecting segment 32.

[0057] What needs to be understood is that the winding direction along the second circumferential direction of the coils 31 on the same group of teeth 11 is the same. For example, each group of teeth 11 may include multiple teeth 11', and the conductor 3 may be wound around these multiple teeth 11' to form multiple coils. In this case, the winding direction along the second circumferential direction of the multiple coils formed on a single group of teeth 11 is the same.

[0058] In the brushless motor of the embodiment of this disclosure, the number of poles P of the magnetic ring 21, the number of multiphase conductors 3 X, and the number of tooth groups 11 Z satisfy the relationship Z = P × X. In other words, each phase conductor 3 is wound around P tooth groups 11, and each magnetic pole corresponds to X tooth groups 11 around which conductors 3 of different phases are wound.

[0059] In some realizations, each tooth group 11 includes a neck portion 111 and a shoe portion 112.

[0060] For example, referring to Figure 1B, each tooth group 11 includes a tooth 11' which includes a neck portion 111 and a shoe portion 112. Alternatively, each tooth group 11 may include multiple teeth 11', each tooth 11' may include an independent neck portion 111 and further include an independent shoe portion 112.

[0061] In these implementations, the conductor 3 is wound around the neck portion 111 of the teeth group 11, and a magnetic field is generated when the conductor 3 is energized (i.e., the strength of the drive signal supplied to the conductor 3 is not zero). Because the winding directions of the coils 31 on two adjacent teeth groups 11 of the same phase are opposite along the second circumferential direction of the teeth group 11, when any one phase of the conductor 3 is energized, the direction of the magnetic field generated in the two adjacent teeth groups 11 around which the conductor 3 of that phase is wound is opposite.

[0062] The following explanation will be based on the brushless motors shown in Figures 1A and 1B. In the brushless motors shown in Figures 1A and 1B, the brushless motor includes two phase conductors 3, which are the first phase conductor X1 and the second phase conductor X2, and the number of poles of the magnet ring 21 is 4, that is, X=2 and P=4. In this case, the number of teeth group 11 (i.e., teeth 11') is Z=8.

[0063] The first phase conductor X1 and the second phase conductor X2 are each wound around four different teeth 11' to form four coils 31.

[0064] Of the four coils 31 formed by the first phase conductor X1, the second phase conductor X2 is wound around one tooth 11' between any two adjacent teeth 11' along the first circumferential direction of the stator core 1, and the winding direction along the second circumferential direction of the teeth 11' of the coils 31 on these two adjacent teeth 11' is opposite.

[0065] Similarly, among the four coils 31 formed by the second phase conductor X2, between any two adjacent teeth 11' along the first circumferential direction, the first phase conductor X1 is wound around one tooth 11', and the winding direction along the second circumferential direction of the coils 31 on these two adjacent teeth 11' is also opposite.

[0066] It should be understood that Figures 1A and 1B merely schematically illustrate that the brushless motor in the embodiment of this disclosure may have an outer rotor structure (i.e., the magnet ring 21 is located outside the stator core 1), but this disclosure is not limited thereto.

[0067] For example, a brushless motor may have an inner rotor structure in which the magnet ring 21 is installed inside the stator core 1.

[0068] Furthermore, for example, the brushless motor may have a planar structure in which the magnet ring 21 and the stator core 1 are superimposed along the axial direction. In some realizations, the brushless motor may include one magnet ring and one stator core superimposed along the axial direction. In some other realizations, the brushless motor may include one magnet ring and two stator cores superimposed along the axial direction, with the magnet ring located between the two stator cores. In some yet another realization, the brushless motor may include two magnet rings and one stator core superimposed along the axial direction, with the stator core located between the two magnet rings.

[0069] The following describes the driving methods for brushless motors according to this disclosure. Figure 2 is a flowchart of the driving methods for brushless motors in some embodiments of this disclosure.

[0070] As shown in Figure 2, the driving method for a brushless motor includes step 210.

[0071] In step 210, N periodically changing drive signals are provided to the N-phase conductor 3 through the independent first and second ends of the N-phase conductor 3 within the X-phase conductor 3. N is any integer between 1 and X, inclusive.

[0072] For example, when X=2, N may be equal to 1 or 2. Also, for example, when X=3, N may be equal to 1, 2, or 3. Also, for example, when X=5, N may be equal to 1, 3, or 5.

[0073] Here, the waveform of each of the N drive signals during one cycle includes a first waveform with an intensity greater than 0 and a second waveform with an intensity less than 0. In other words, the intensity of each drive signal changes between positive and negative within one cycle.

[0074] In some embodiments, the frequencies of the N drive signals are the same.

[0075] In some embodiments, the amplitudes of at least two of the N drive signals are different. In other embodiments, the amplitudes of the N drive signals are the same.

[0076] In some embodiments, the first and second waveforms of each drive signal are centrally symmetric. To understand this, the first and second waveforms are centrally symmetric if, within one cycle of the drive signal, one of the first and second waveforms can overlap with the other after being inverted and moved parallel along the horizontal axis.

[0077] In some embodiments, the waveforms of the N drive signals are all square waves. In other embodiments, the first and second waveforms of each of the N drive signals are sine waves. For example, the waveforms of the N drive signals are all sine waves. In yet another embodiment, the waveforms of the N drive signals are not square waves, and the first and second waveforms are not sine waves. For example, the waveforms of the N drive signals are all bimodal or other waveforms.

[0078] The operating principle of the brushless motor according to this disclosure will be explained below by linking Figures 3A, 3B, and 3C. Figures 3A, 3B, and 3C are schematic diagrams of the operating principles of brushless motors in several embodiments of this disclosure. For ease of understanding, Figures 3A, 3B, and 3C show the magnetic ring 21 and teeth 11' in the brushless motor shown in Figures 1A and 1B in a linearly unfolded form.

[0079] In Figures 3A, 3B, and 3C, N=X=2. That is, a drive signal is provided to the first phase conductor X1 via its first and second ends (X1-IN and X1-OUT), and at the same time, a drive signal is provided to the second phase conductor X2 via its first and second ends (X2-IN and X2-OUT).

[0080] For the sake of clarity, in these diagrams, the teeth 11' around which the first phase conductor X1 is wound are represented from left to right as X1(1), X1(2), X1(3), and X1(4), respectively, and the teeth 11' around which the second phase conductor X2 is wound are represented from left to right as X2(1), X2(2), X2(3), and X2(4).

[0081] As mentioned above, since the winding directions along the circumferential direction of the teeth 11' of the coil 31 on two adjacent teeth 11' of the same phase conductor 3 are opposite, if the strength of the drive signal for the first phase conductor X1 is not zero (i.e., the first phase conductor X1 is energized), a magnetic field in the opposite direction is generated at any two adjacent locations among X1(1), X1(2), X1(3), and X1(4). Similarly, if the strength of the drive signal for the second phase conductor X2 is not zero (i.e., the second phase conductor X2 is energized), a magnetic field in the opposite direction is generated at any two adjacent locations among X2(1), X2(2), X2(3), and X2(4).

[0082] First, referring to Figure 3A, the singularity O of each of the four magnetic poles (i.e., the midpoint of each magnetic pole in the circumferential direction of the stator core 1) is directly opposite the shoe portions 112 of X1(1), X1(2), X1(3), and X1(4), respectively. At this time, the intensity of the drive signal supplied to the first phase conductor X1 is either positive or negative (let's assume it's positive), and in this case, an NSNS magnetic field is sequentially generated at X1(1), X1(2), X1(3), and X1(4). The intensity of the drive signal supplied to the second phase conductor X2 is either positive or negative (let's assume it's positive as well), and in this case, an NSNS magnetic field is sequentially generated at X2(1), X2(2), X2(3), and X2(4). Under the influence of the magnetic force, the magnet ring 21 rotates along the direction of the arrow shown in Figure 3A.

[0083] After rotating by a certain angle (for example, 90°), the relative positional relationship between the magnet ring 21 and the teeth 11' is such that, as shown in Figure 3B, the singularity O of each of the four magnetic poles faces directly toward the shoe portions 112 of X2(1), X2(2), X2(3), and X2(4), respectively. At this time, the intensity of the drive signal supplied to the first phase conductor X1 remains positive, and magnetic fields of NSNS are sequentially generated at X1(1), X1(2), X1(3), and X1(4).

[0084] However, the strength of the drive signal supplied to the second phase conductor X2 switches from positive to negative, and the magnetic fields generated sequentially in X2(1), X2(2), X2(3), and X2(4) change from NSNS to SNSN. Under the influence of the magnetic force, the magnet ring 21 continues to rotate along the direction of the arrow.

[0085] After rotating again by a certain angle (for example, 90°), the relative positional relationship between the magnetic ring 21 and the teeth 11' is such that, as shown in Figure 3C, the singularity O of each of the four magnetic poles is again directly facing the shoe portions 112 of X1(1), X1(2), X1(3), and X1(4), respectively. At this time, the intensity of the drive signal supplied to the first phase conductor X1 switches from positive to negative, and in this case, the magnetic fields generated sequentially at X1(1), X1(2), X1(3), and X1(4) change from NSNS to SNSN. The intensity of the drive signal supplied to the second phase conductor X2 remains negative, and SNSN magnetic fields are sequentially generated at X2(1), X2(2), X2(3), and X2(4). Under the influence of the magnetic force, the magnetic ring 21 continues to rotate along the direction of the arrow.

[0086] Since the subsequent process is similar to that described above, no further explanation will be given here. As can be seen from the above explanation, by providing the first phase conductor X1 and the second phase conductor X2 with drive signals whose intensity changes between positive and negative within one cycle, the magnet ring 21 can be continuously rotated in the same direction.

[0087] It should be understood that the above explanation uses the example of a drive signal provided to each phase's conductor 3 undergoing a phase reversal (i.e., positive / negative switching) when the shoe portion 112 of the teeth group 11 around which the conductor 3 of that phase is wound aligns directly with the singularity O of the magnetic poles. In this case, the efficiency of the brushless motor can be improved. However, in some embodiments, the drive signal may undergo a phase reversal when the shoe portion 112 does not align directly with the singularity O of the magnetic poles.

[0088] In the driving method for a brushless motor according to this disclosure, N drive signals are provided to the N-phase conductor 3 via independent first and second ends of the N-phase conductor 3. In such a system, as N increases, the torque provided by the brushless motor increases, and control remains relatively simple because the N drive signals are independent of each other. Thus, a brushless motor can be driven to provide a relatively large torque with a simple control method.

[0089] Furthermore, the drive method for a brushless motor according to the embodiment of this disclosure allows for the provision of drive signals to different numbers of N-phase conductors 3 in different scenarios, thereby enabling the brushless motor to operate under different operating conditions. In this way, the versatility of the brushless motor can be improved.

[0090] For the case where 2 ≤ N ≤ X, the drive method for the brushless motor according to this disclosure can be further divided into two different methods: cross-energy and alternating energy, depending on whether the N-phase conductor 3 remains energized within the same time period. These two methods will be described below.

[0091] First, let me explain the cross-voltage method.

[0092] In the cross-current system, the intensity of the N drive signals supplied to the N-phase conductor 3 within the first period is continuously non-zero. In other words, the N-phase conductor 3 remains energized within the same first period, meaning that there are overlapping portions within the period in which the N-phase conductor 3 remains energized. In this way, the utilization rate of the windings and core in a brushless motor can be improved.

[0093] In conventional three-phase DC brushless motors, the utilization rate of the windings and core is only about 66% because two phase windings are energized within the same time period while one phase winding is not. For example, when N=X, the X-phase conductor 3 remains energized within the same first time period, meaning that the utilization rate of the windings and core within the first time period in a brushless motor can reach a limit utilization rate of 100%, which is superior to conventional three-phase DC brushless motors.

[0094] The following describes several embodiments of the cross-current drive system, linking Figures 4A, 4B, and 5. Figure 4A is a waveform diagram of the drive signal in a cross-current drive system based on several embodiments of the present disclosure. Figure 4B is a waveform diagram of the drive signal in a cross-current drive system based on yet another embodiment of the present disclosure. Figure 5 is a waveform diagram of the drive signal in a cross-current drive system based on yet another embodiment of the present disclosure.

[0095] In some embodiments, the time at which a first waveform with an intensity greater than 0 and a second waveform with an intensity less than 0 overlap in each drive signal is the first time, and the intensity of each drive signal is continuously non-zero within any period other than the first time in one cycle.

[0096] In other words, in these embodiments, the waveforms of each drive signal provided are all continuous. That is, the intensity of each drive signal provided is not continuously zero within any given time period, but is zero only when the positive / negative switching occurs (i.e., the first time point).

[0097] For example, referring to Figures 4A and 4B, the waveforms of the drive signals supplied to each phase conductor are all sine waves. At the first time point when the first and second waveforms of the drive signal overlap, the intensity of the drive signal is 0. Within any time period other than the first time point, the intensity of the drive signal is continuously non-zero.

[0098] Figure 4A schematically shows the case where X=N=2. In this case, the phase difference between the drive signal of the first phase conductor and the drive signal of the second phase conductor is θ 12That is the case.

[0099] Figure 4B schematically shows the case where X=N=3. In this case, the phase difference between the drive signal of the first phase conductor and the drive signal of the second phase conductor is θ 12 Therefore, the phase difference between the drive signal of the second phase conductor and the drive signal of the third phase conductor is θ 23 Therefore, the phase difference between the drive signal of the first phase conductor and the drive signal of the third phase conductor is θ 13 That is the case.

[0100] In these embodiments, the first period during which the N-phase conductor 3 remains energized simultaneously is longer, thereby further improving the utilization rate of the windings and core in the brushless motor. For example, when N=X, the utilization rate of the windings and core in the brushless motor can reach a limit utilization rate of 100% within a longer period of time.

[0101] Furthermore, if the N-phase conductor 3 remains energized, the internal vibration of the stator core 1 is reduced, thereby reducing the electromagnetic noise generated during brushless motor operation and extending the lifespan of the bearings in the brushless motor.

[0102] As one of several implementations, as shown in Figures 4A and 4B, in the cross-energy system, all N drive signals are continuous sine waves. In this system, each drive signal can complete the rotation of a pair of magnetic rings with only two switching energization cycles. For the same rotational speed and torque, a conventional three-phase DC brushless motor requires six switching energization cycles to complete the rotation of a pair of magnetic rings.

[0103] Therefore, in the cross-current method, the brushless motor is driven using a drive signal with a sinusoidal waveform, which reduces the processing power required by the chip providing the drive signal.

[0104] In some other embodiments, the intensity of each drive signal within a second period band during one cycle is continuously zero. In other words, in these embodiments, the waveforms of each drive signal provided are all intermittent rather than continuous.

[0105] In some implementations, the intensity of each drive signal at any time other than the second period within one cycle is not zero.

[0106] For example, referring to Figure 5, the drive signals supplied to the first phase conductor and the drive signals supplied to the second phase conductor are both discontinuous waveforms, and both the first and second waveforms correspond to a sine function.

[0107] Specifically, the drive signal for the first phase conductor can be obtained by advancing the phase conversion position of a continuous sinusoidal wave signal by a phase angle of f1' and delaying it by a phase angle of f1'', and the drive signal for the second phase conductor can be obtained by advancing the phase conversion position of a continuous sinusoidal wave signal by a phase angle of f2' and delaying it by a phase angle of f2''.

[0108] In this case, the intensity of each drive signal during the period in which the phase conversion position is advanced or delayed is continuously 0, while the intensity at any time outside of this period is not 0.

[0109] As mentioned above, it is preferable that the drive signal provided to each phase wire 3 undergoes a phase change when the shoe portion 112 of the tooth group 11 around which the conductor 3 of that phase is wound aligns directly with the singularity of the magnetic pole. However, in reality, due to various reasons (for example, the average assignment angle of the magnetic ring type of the brushless motor may have errors due to production, and for example, there may be errors in the drive detection of the brushless motor), it may not be possible to precisely control the timing at which the phase change point aligns directly with the singularity of the magnetic pole. Instead, by moving ahead or behind this time to some extent, the windings perform unnecessary work during the period in which they move ahead or behind this time, thereby reducing the efficiency of the brushless motor.

[0110] By providing a drive signal whose intensity is consistently 0 within the second time period and whose intensity is not 0 at any time outside the second time period, the efficiency of the brushless motor can be improved by reducing unnecessary winding work.

[0111] Next, the alternating current drive system will be explained by linking Figures 6A and 6B. Figure 6A is a waveform diagram of the drive signal in an alternating current drive system based on several embodiments of the present disclosure. Figure 6B is a waveform diagram of the drive signal in an alternating current drive system based on several other embodiments of the present disclosure.

[0112] In the alternating energization system, within the period in which the intensity of any one drive signal is not zero during one cycle, the intensity of all other drive signals among the N drive signals is zero. 2 ≤ N ≤ X.

[0113] In other words, in the alternating energization method, each drive signal is intermittent and discontinuous, and no two phases of conductors 3 will remain energized simultaneously within any given time period.

[0114] For example, referring to Figures 6A and 6B, the waveforms of the drive signals supplied to each phase conductor are all square waves. During the period in which the drive signal of any one phase conductor is continuously non-zero, the intensity of the drive signals of the other phase conductors is zero. Figure 6A schematically shows the case where X=N=2. Figure 6B schematically shows the case where X=N=3.

[0115] Since only one drive signal intensity remains non-zero within the same time period, the control can be further simplified by using an alternating power supply drive method to drive the brushless motor.

[0116] Compared to drive signals with other waveforms, providing control for a drive signal with a square wave waveform is simpler. Therefore, in an alternating energization system, using a drive signal with a square wave waveform to drive a brushless motor can further simplify control.

[0117] So far, we have explained two drive methods: cross-current and alternating current.

[0118] It should be understood that the above only schematically shows that the drive signal matches a sine function in a cross-current drive system, but the waveform of the drive signal in an alternating current drive system is a square wave, and the embodiments of this disclosure are not limited to this.

[0119] In some embodiments, a brushless motor can be driven by employing one of two drive methods: cross-energy and alternating energy flow. In other embodiments, a brushless motor can also be driven by a method that combines cross-energy and alternating energy flow.

[0120] The following describes some embodiments of the driving method for brushless motors according to this disclosure. It should be understood that these embodiments are applicable to both cross-energy driving and alternating-energy driving.

[0121] In some embodiments, when N is 2 or greater, the magnetic ring 21 can be driven to rotate in different directions by adjusting the order in which the drive signals are provided to the N-phase conductor 3.

[0122] The following explanation will use the cases shown in Figures 6C and 6D as examples. Figures 6C and 6D are waveform diagrams of drive signals in a cross-current drive system based on some further embodiments of the present disclosure.

[0123] As shown in Figure 6C, a drive signal for the first phase conductor is provided to the first phase conductor from time t0, and a drive signal for the second phase conductor is provided to the second phase conductor from time t1 after time t0. That is, first, a drive signal for the first phase conductor is provided to the first phase conductor, and then a drive signal for the second phase conductor is provided to the second phase conductor. In this case, the magnet ring 21 can rotate in the first direction (for example, clockwise).

[0124] As shown in FIG. 6D, a driving signal for the second-phase conductor is provided to the second-phase conductor from time t0, and a driving signal for the first-phase conductor is provided to the first-phase conductor from time t1 after time t0. That is, first, a driving signal for the second-phase conductor is provided to the second-phase conductor, and then a driving signal for the first-phase conductor is provided to the first-phase conductor. In this case, the magnet ring 21 can rotate in a second direction (e.g., counterclockwise direction) opposite to the first direction.

[0125] Thus, by adjusting the order in which driving signals are provided to the N-phase conductors 3, the magnet ring 21 can be driven to rotate in different directions, thereby improving the versatility of the brushless motor.

[0126] In some embodiments, the brushless motor includes one or more stator cores 1, and the X-phase conductors 3 are sequentially wound around the tooth groups 11 in order from the first to the X-phase along the first circumferential direction of the stator core 1. The N-phase conductors include an i-phase conductor and a k-phase conductor.

[0127] In this case, the phase difference θ ik between the driving signal of the i-phase conductor and the driving signal of the k-phase conductor satisfies the following equation:

Equation

[0128] In some embodiments, the range of values of θ ik is [1°, 180°]. In some implementation forms, the range of values of θ ik is [15°, 120°]. For example, θ ik can take an integer multiple of 15°, such as 15°, 30°, 45°, 60°, etc.

[0129] In the same stator core 1, the tooth group 11 of the X-phase conductor and the adjacent tooth groups 11 on both sides all have gaps at the closest positions.

[0130] For example, if a brushless motor includes one stator core 1, the adjacent tooth groups 11 on both sides of the tooth group 11 of the X-phase conductor are the tooth groups 11 of the conductors of other phases. Also, for example, if a brushless motor includes multiple stator cores 1 superimposed along the axial direction, the adjacent tooth groups 11 on both sides of the tooth group 11 of the X-phase conductor are the tooth groups 11 of the conductors of the same phase.

[0131] Each gap has a central position in the first circumferential direction. In all gaps formed by Z tooth groups 11, the center angle corresponding to the arc between the central position of the X-phase conductor and the central position adjacent to it in the first circumferential direction is βx, and the sector area corresponding to the arc includes at least some of the tooth groups 11 of the X-phase conductor.

[0132] For example, referring to Figure 6E, the brushless motor may include two stator cores 1 superimposed along the axial direction, the first stator core 1 being shown by a solid line and the second stator core 1 by a dashed line. In the first stator core 1, two adjacent groups of teeth have a gap between them at their closest positions, and in the second stator core 1, two adjacent groups of teeth also have a gap between them at their closest positions. In this case, the concentric angle β1 of the first phase conductor is the concentric angle corresponding to the arc between one center position of the first phase conductor and one adjacent center position of the first phase conductor in the first circumferential direction of the second phase conductor.

[0133] For the sake of explanation, β X This can be briefly described as the central angle of the Xth phase conductor.

[0134] For example, when X=2, i=1 and k=2, which means the phase difference θ is between the drive signal of the first phase conductor and the drive signal of the second phase conductor. 12 = β1 × P / 2

[0135] Furthermore, for example, when X=3, there are three possible values. In the first case, i=1 and k=2, that is, the phase difference θ between the drive signal of the first phase conductor and the drive signal of the second phase conductor. 12=β1×P / 2. In the second case, i=2 and k=3, that is, the phase difference θ between the drive signal of the second phase conductor and the drive signal of the third phase conductor. 23 =β² × P / 2. In the third case, i=l and k=3, that is, the phase difference θ between the drive signal of the first phase conductor and the drive signal of the third phase conductor. 13 = (β1 + β2) × P / 2

[0136] Connecting Figure 1A, we find that the central angle β1 of the first phase conductor X1 is 45°, the central angle β2 of the second phase conductor X2 is 45°, and the number of poles P of the magnet ring 21 is 4.

[0137] In this case, referring to Figures 4A and 6A, the phase difference θ between the drive signal of the first phase conductor and the drive signal of the second phase conductor is... 12 = 2 × 45° = 90°.

[0138] It should be understood that while Figure 1A schematically shows that the circular angles of the conductors 3 of different phases are equal, the embodiments of this disclosure are not limited to this, and only require that the sum of the circular angles of the conductors 3 of different phases is equal to β. Referring to Figure 1A, β is the circular angle in the first circumferential direction of a single magnetic pole of the magnetic ring 21, and its magnitude is equal to the value obtained by dividing 360° by the number of poles P of the magnetic pole.

[0139] Taking the brushless motor shown in Figure 1A as an example, X=2 and P=4, in which case β=90°. That is, β1 and β2 can be any angles greater than 0° and less than 90°, as long as β1+β2=90° is satisfied.

[0140] In the above embodiment, the phase difference between the drive signals provided to any two phases of the conductor 3 is determined based on the number of poles of the magnet ring 21 and the structural parameters of the stator core 1. In this way, the operation of the brushless motor can be controlled accurately and stably.

[0141] As described above, by providing drive signals to a different number of N-phase conductors 3, a brushless motor can be driven to operate under different operating conditions. In this regard, the present disclosure further provides a driving method for a brushless motor in the following embodiments.

[0142] Figure 7 is a flowchart of a driving method for a brushless motor based on some other embodiments of the present disclosure.

[0143] As shown in Figure 7, the driving method for a brushless motor further includes step 220 and step 230. Steps 220 and 230 can be performed before step 210.

[0144] In step 220, the N-phase lead wire and the first amplitude of each drive signal are determined based on the target torque of the rotor.

[0145] In some realizations, when the target torque is large, N becomes large. In some other realizations, when the target torque is large, the first amplitude of each drive signal becomes large. In some yet another realization, when the target torque is large, N becomes large AND the first amplitude of each drive signal becomes large.

[0146] In step 230, the first frequency of each drive signal is determined based on the target rotational speed of the rotor.

[0147] In some implementations, when the target rotational speed is high, the first frequency of each drive signal increases.

[0148] In this way, by adjusting the frequency and amplitude of the N-phase wire and drive signal according to the target torque and target rotational speed of the rotor, the brushless motor can be driven to operate under conditions that have the target torque and target rotational speed.

[0149] In some embodiments, when the target torque of the rotor is higher than a first preset torque, N = X. That is, when the target torque of the rotor is higher than the first preset torque, a drive signal is provided to the conducting wire 3 of each phase of the brushless motor. In such a manner, by providing a drive signal to the conducting wire 3 of each phase of the brushless motor, the brushless motor can be driven to operate in an operating condition with a relatively high target torque.

[0150] In some implementation forms, when the target torque of the rotor is higher than a first preset torque, N = X, and the first amplitudes of the N drive signals are the same. In such a manner, since the amplitudes provided to the conducting wire 3 of each phase are the same, the brushless motor can be driven to operate in an operating condition with a relatively high target torque in a simple control manner.

[0151] In some embodiments, when the target torque of the rotor is lower than a second preset torque, N < X, and the first amplitudes of the N drive signals are the same. In such a manner, since the amplitudes provided to the N-phase conducting wire 3 are the same, the brushless motor can be driven to operate in an operating condition with a relatively low target torque in a simple control manner.

[0152] In some other embodiments, when the target torque of the rotor is lower than a second preset torque, N = X, and the first amplitudes of at least two of the N drive signals are different. In such a manner, by providing a drive signal with a relatively large amplitude to a part of the X-phase conducting wire 3 and providing a drive signal with a relatively small amplitude to other conducting wires 3, the brushless motor can be driven to operate in an operating condition with a relatively low target torque.

[0153] In some embodiments, the first frequency and the first amplitude of each of the N drive signals can be determined in the following manner.

[0154] First, from multiple sets of parameters, one set of parameters can be selected to reach the requirements for the target rotational speed and target torque. This set of parameters represents the second frequency and second amplitude of each drive signal. Then, based on the selected set of parameters, the first frequency and first amplitude of each drive signal can be determined.

[0155] For example, each set of parameters among several sets of parameters is used to enable the rotor to reach different rotational speeds and torques. These sets of parameters can be pre-stored in a memory unit. The memory unit may be, for example, read-only memory (ROM).

[0156] After obtaining the current target rotational speed and target torque of the rotor in a brushless motor, a set of parameters matching the target rotational speed and target torque can be retrieved from these multiple sets of parameters based on the target rotational speed and target torque. Then, the second frequency and second amplitude represented by this set of parameters can be fine-tuned according to the actual operating conditions of the brushless motor (e.g., friction force) to obtain the first frequency and first amplitude for each drive signal.

[0157] In these embodiments, a set of parameters that allow the rotor to reach the required target rotational speed and target torque can be directly invoked, and a first frequency and first amplitude of each drive signal can be determined based on this set of parameters. Such a method can reduce the amount of computation that needs to be performed in real time when driving a brushless motor.

[0158] Embodiments of this disclosure further provide drive systems for brushless motors.

[0159] Figure 8 is a schematic diagram of the structure of a drive unit for a brushless motor based on some embodiments of the present disclosure. The brushless motor includes a stator core 1, a rotor 2, and X-phase conductors 3, where X ≥ 2. The stator core 1 includes Z groups of teeth 11 spaced apart along a first circumferential direction. The rotor 2 includes a magnetic ring 21 with P poles (where P is even). The X-phase conductors 3 are wound around the groups of teeth 11 to form coils 31, where Z = P × X. In conductors 3 of the same phase, the winding directions along the second circumferential direction of the coils 31 on two adjacent groups of teeth 11 are opposite and arranged at intervals of X-1 groups of teeth 11.

[0160] As shown in Figure 8, the drive unit 800 for the brushless motor includes a supply module 801.

[0161] The providing module 801 is configured to provide N periodically changing drive signals to the N-phase conductor 3 via independent first and second ends of the N-phase conductor 3, where 1 ≤ N ≤ X, and the waveform of each drive signal in one period includes a first waveform with an intensity greater than 0 and a second waveform with an intensity less than 0.

[0162] In some embodiments, the intensity of N drive signals within a first period is continuously non-zero. That is, the drive unit 800 for the brushless motor can drive the brushless motor in a cross-energy manner.

[0163] In some other embodiments, 2 ≤ N ≤ X, and within the period in which the intensity of any one drive signal in one cycle is not zero, the intensity of all other drive signals among the N drive signals is zero. That is, the drive unit 800 for the brushless motor can drive the brushless motor in an alternating energization manner.

[0164] It should be understood that the drive unit 800 for the brushless motor may further include various other modules for performing the drive method for the brushless motor of any one of the embodiments described above. Relevant details should be found in the preceding paragraph and will not be explained further here.

[0165] Figure 9 is a schematic diagram of the structure of a drive unit for a brushless motor based on some other embodiments of the present disclosure.

[0166] As shown in Figure 9, the drive unit 900 for the brushless motor includes a memory 901 and a processor 902 coupled to the memory 901, the processor 902 being configured to execute the drive method for the brushless motor of any one of the above embodiments based on instructions stored in the memory 901.

[0167] Memory 901 may include, for example, system memory, a fixed non-volatile storage medium, etc. System memory may store, for example, an operating system, application programs, a boot loader, and other programs.

[0168] The drive unit 900 may further include an input / output interface 903, a network interface 904, a storage interface 905, and the like. Connections between these input / output interfaces 903, network interface 904, and storage interface 905, and between the memory 901 and the processor 902, can be made via, for example, a bus 906. The input / output interface 903 provides a connection interface to input / output devices such as a display, mouse, keyboard, and touchscreen. The network interface 904 provides a connection interface to various network devices. The storage interface 905 provides a connection interface to external storage devices such as SD cards and U disks.

[0169] Embodiments of the present disclosure further provide a computer-readable storage medium containing computer program instructions, which, when executed by a processor, realize a driving method for a brushless motor according to any one of the embodiments described above.

[0170] Embodiments of this disclosure further provide a drive circuit for a brushless motor. The brushless motor includes a stator core 1, a rotor 2, and X-phase conductors 3, where X ≥ 2. The stator core 1 includes Z groups of teeth 11 spaced apart along a first circumferential direction. The rotor 2 includes a magnetic ring 21 with P poles (where P is even). The X-phase conductors 3 are wound around the groups of teeth 11 to form coils 31, where Z = P × X. In conductors 3 of the same phase, the winding directions of the coils 31 on two adjacent groups of teeth 11 along the second circumferential direction of the groups of teeth 11 are opposite and are arranged at intervals of X-1 groups of teeth 11. Figure 10A is a schematic diagram of the structure of a drive circuit for a brushless motor based on some embodiments of the present disclosure. Figure 10B is a schematic diagram of the structure of a drive circuit for a brushless motor based on some other embodiments of the present disclosure.

[0171] Figure 10A shows the case where X=2, and Figure 10B shows the case where X=3. Referring to Figures 10A and 10B, the drive circuit for the brushless motor includes X full-bridge circuits 1010. Each full-bridge circuit 1010 includes two half-bridge circuits 1011 connected in parallel between the input terminal VIN and the ground terminal GND of the drive circuit.

[0172] Each half-bridge circuit 1011 includes two switches S1 and S2 connected via node P. Switches S1 and S2 may be, for example, thyristors (also called thyristors), metal oxide semiconductors (MOSFETs), or insulated gate bipolar transistors (IGBTs).

[0173] Each full-bridge circuit 1010 has two half-bridge circuits 1011, which include a first half-bridge circuit 1011a and a second half-bridge circuit 1011b. Here, node P of the first half-bridge circuit 1011a in the i-th full-bridge circuit 1010 is configured to be connected to the first end of the i-th phase conductor, and node P of the second half-bridge circuit 1011b in the i-th full-bridge circuit 1010 is configured to be connected to the second end of the i-th phase conductor 3. 1 ≤ i ≤ X.

[0174] In other words, X full-bridge circuits 1010 correspond one-to-one with X phase conductors 3 in the brushless motor BM. In each full-bridge circuit 1010, node P of the first half-bridge circuit 1011a is connected to the first end of the corresponding single-phase conductor 3, and the second half-bridge circuit 1011b is connected to the second end of the corresponding single-phase conductor 3.

[0175] For example, referring to Figure 10A, the nodes P of the two first half-bridge circuits 1011a are connected to the first end X1-IN of the first phase conductor and the first end X2-IN of the second phase conductor, respectively, while the nodes P of the two second half-bridge circuits 1011b are connected to the second end X1-OUT of the first phase conductor and the second end X2-OUT of the second phase conductor, respectively.

[0176] Furthermore, referring to Figure 10B, for example, the nodes P of the three first half-bridge circuits 1011a are connected to the first end X1-IN of the first phase conductor, the first end X2-IN of the second phase conductor, and the first end X3-IN of the third phase conductor, respectively. The nodes P of the three second half-bridge circuits 1011b are connected to the second end X1-OUT of the first phase conductor, the second end X2-OUT of the second phase conductor, and the second end X3-OUT of the third phase conductor, respectively.

[0177] By controlling the states of switches S1 and S2 in the drive circuit for the brushless motor of the above embodiment, the drive circuit can provide N drive signals to the N-phase conductor of the brushless motor according to the driving method for the brushless motor of any one of the above embodiments.

[0178] In some embodiments, N of the X full-bridge circuits 1010 are configured to provide N periodically changing drive signals to the N-phase conductor 3 via the independent first and second ends of each N-phase conductor 3 within one control cycle, such that 1 ≤ N ≤ X.

[0179] Here, the waveform of each drive signal in one cycle includes a first waveform with an intensity greater than 0 and a second waveform with an intensity less than 0. In some embodiments, the frequencies of the N drive signals provided by the drive circuit are the same.

[0180] For example, of the two switches S1 and S2 of each half-bridge circuit 1011, the first switch S1 is connected to the input terminal VIN of the drive circuit, and the second switch S2 is connected to the ground terminal GND of the drive circuit.

[0181] In this case, the i-th full-bridge circuit 1010 can be controlled to provide the i-th phase conductor with a first waveform whose intensity is greater than 0 by controlling the first switch S1 in the first half-bridge circuit 1011a of the i-th full-bridge circuit 1010 to be ON and the second switch S2 in the second half-bridge circuit 1011b of the i-th full-bridge circuit 1010 to be ON and the first switch S1 to be OFF.

[0182] Conversely, by controlling the first switch S1 in the second half-bridge circuit 1011b of the i-th full-bridge circuit 1010 to be ON and the second switch S2 to be OFF, and by controlling the second switch S2 in the first half-bridge circuit 1011a of the i-th full-bridge circuit 1010 to be ON and the first switch S1 to be OFF, the i-th full-bridge circuit 1010 can be controlled to provide the i-th phase conductor with a second waveform whose intensity is less than 0.

[0183] In some embodiments, the first switch S1 connected to the input terminal VIN of the drive circuit is either an n-type MOSFET or a p-type MOSFET, and the second switch S2 connected to the ground terminal GND of the drive circuit is an n-type MOSFET. For example, the first switch S1 is an n-type MOSFET. Alternatively, for example, the first switch S1 is a p-type MOSFET. In this way, the stability of the drive can be improved.

[0184] In some embodiments, the amplitudes of at least two of the N drive signals provided by the drive circuit are different. In some other embodiments, the amplitudes of the N drive signals provided by the drive circuit are the same.

[0185] In some embodiments, the first and second waveforms of each drive signal provided by the drive circuit are centrally symmetrical.

[0186] In some embodiments, the waveforms of the N drive signals provided by the drive circuit are all square waves. In some other embodiments, the first waveform and the second waveform coincide with a sine function.

[0187] In some embodiments, the X-phase conductor 3 is wound sequentially around the teeth group 11 in the order of the first to the X-phase along the first circumferential direction. The N-phase conductor includes the i-th phase conductor and the k-th phase conductor.

[0188] The phase difference θ between the drive signal for the i-th phase conductor and the drive signal for the k-th phase conductor, provided by the drive circuit. ikIt satisfies the following equation,

number

[0189] In the same stator core 1, the teeth group 11 of the X-phase conductor and the adjacent teeth groups 11 on both sides have a gap at the closest position, and the gap has a central position in the first circumferential direction.

[0190] In all gaps formed by Z tooth groups 11, the central angle corresponding to the arc between the center position of the Xth phase conductor and the first circumferentially adjacent center position is βx, and the sector area corresponding to the arc includes at least some of the tooth groups 11 of the Xth phase conductor.

[0191] In one form of implementation, the drive circuit for the brushless motor provides N drive signals to the N-phase conductor 3 in a cross-energized manner.

[0192] In these implementations, the intensity of the N drive signals within the first time period is continuously non-zero. That is, the intensity of any of the N drive signals within the same time period is continuously non-zero.

[0193] In some embodiments, the time at which the first and second waveforms of each drive signal provided by the drive circuit overlap is the first time, and the intensity of each drive signal within any period other than the first time of one cycle is continuously non-zero. That is, all drive signals are continuous and not intermittent.

[0194] In some other embodiments, the intensity of each drive signal provided by the drive circuit within a second period within one cycle is continuously zero; that is, the drive signal is intermittent. In some realizations, the intensity of each drive signal provided by the drive circuit at any time outside of the second period within one cycle is not zero.

[0195] In some other realizations, the drive circuit for the brushless motor provides N drive signals to the N-phase conductor 3 in an alternating energizing manner.

[0196] In these implementations, within a period where the intensity of any one drive signal in one cycle is not zero, the intensity of all other drive signals among the N drive signals is zero. That is, the intensity of any two drive signals provided by the drive circuit remains non-zero if they are different.

[0197] Figure 11 is a flowchart of a control method for a drive circuit for a brushless motor based on some embodiments of the present disclosure.

[0198] As shown in Figure 11, a method for controlling a drive circuit for a brushless motor includes step 1110.

[0199] In step 1110, within one control cycle, the N full-bridge circuits provide N periodically changing drive signals to the N-phase conductors via the independent first and second ends of each of the N-phase conductors by controlling the switching on one switch in the first half-bridge circuit and one switch in the second half-bridge circuit of each of the N full-bridge circuits.

[0200] Here, 1 ≤ N ≤ X, and the waveform of each drive signal in one period includes a first waveform with an intensity greater than 0 and a second waveform with an intensity less than 0.

[0201] In this way, the N full-bridge circuits in the drive circuit for the brushless motor of any one of the above embodiments can be controlled to provide N periodically changing drive signals to the N-phase conductor 3 via the independent first and second ends of each N-phase conductor 3.

[0202] Figure 12 is a flowchart of a control method for a drive circuit for a brushless motor based on some other embodiments of the present disclosure.

[0203] As shown in FIG. 12, the control method of the drive circuit for the brushless motor further includes steps 1120 to 1130.

[0204] In step 1120, based on the target torque of the rotor, the first amplitudes of the N-phase conductors and each drive signal are determined.

[0205] In step 1130, based on the target rotation speed of the rotor, the first frequencies of each drive signal are determined.

[0206] Steps 1120 and 1130 can be executed before step 1110.

[0207] In this way, the drive circuit can be controlled based on the target torque and target rotation speed of the rotor, whereby the drive circuit can drive the brushless motor to operate in an operating state having the target torque and target rotation speed, and provide N drive signals.

[0208] In some embodiments, when the target torque is higher than the first preset torque, N = X. In some implementation forms, when the target torque is higher than the first preset torque, the first amplitudes of the N drive signals are the same.

[0209] In some embodiments, when the target torque is lower than the second preset torque, N < X, and the first amplitudes of the N drive signals are the same. In some other embodiments, when the target torque is lower than the second preset torque, N = X, and the first amplitudes of at least two of the N drive signals are different.

[0210] In some embodiments, a set of parameters that reaches the requirements of the target rotation speed and target torque is called from a plurality of sets of parameters, and this set of parameters represents the second frequency and second amplitude of each drive signal. Then, based on this set of called parameters, the first frequency and first amplitude of each drive signal are determined.

[0211] Since the control method for the drive circuit for the brushless motor basically corresponds to the embodiment of the drive method for the brushless motor described above, the description is relatively simple, and relevant parts should be referred to in the above explanation.

[0212] Embodiments of the present disclosure further provide control devices for drive circuits for brushless motors.

[0213] Figure 13 is a schematic diagram of the structure of a control device for a drive circuit for a brushless motor based on some embodiments of the present disclosure.

[0214] As shown in Figure 13, the control device 1300 for the drive circuit of the brushless motor includes a control module 1301.

[0215] The control module 1301 controls the N full-bridge circuits to turn on one switch in the first half-bridge circuit and one switch in the second half-bridge circuit of each of the N full-bridge circuits out of the X full-bridge circuits, within one control cycle, so that the N full-bridge circuits provide N periodically changing drive signals to the N-phase conductors via the independent first and second ends of each N-phase conductor.

[0216] Here, 1 ≤ N ≤ X, and the waveform of each drive signal in one period includes a first waveform with an intensity greater than 0 and a second waveform with an intensity less than 0.

[0217] In some embodiments, the control module 1301 controls the drive circuit so that the drive circuit provides a drive signal to the brushless motor in a cross-energy configuration. In some other embodiments, the control module 1301 controls the drive circuit so that the drive circuit provides a drive signal to the brushless motor in an alternating-energy configuration.

[0218] It should be understood that the control device 1300 may further include various other modules that perform the control method for the drive circuit for the brushless motor of any one of the embodiments described above.

[0219] Figure 14 is a schematic diagram of the structure of a control device for a drive circuit for a brushless motor based on some other embodiments of the present disclosure.

[0220] As shown in Figure 14, the control device 1400 for the drive circuit for the brushless motor includes a memory 1401 and a processor 1402 coupled to the memory 1401, the processor 1402 being configured to execute the control method for the drive circuit for the brushless motor of any one of the embodiments described above, based on instructions stored in the memory 901.

[0221] Memory 1401 may include, for example, system memory, a fixed non-volatile storage medium, etc. System memory may store, for example, an operating system, application programs, a boot loader, and other programs.

[0222] The control device 1400 may further include an input / output interface 1403, a network interface 1404, a storage interface 1405, and the like. These input / output interfaces 1403, network interface 1404, and storage interface 1405, and the memory 1401 and the processor 1402, can be connected, for example, via a bus 1406. The input / output interface 1403 provides a connection interface to input / output devices such as a display, mouse, keyboard, and touchscreen. The network interface 1404 provides a connection interface to various network devices. The storage interface 1405 provides a connection interface to external storage devices such as SD cards and U disks.

[0223] Embodiments of the present disclosure further provide a drive system for a brushless motor. The drive system includes a drive circuit for a brushless motor according to any one embodiment described above, and a control device for the drive circuit for a brushless motor according to any one embodiment described above (e.g., control device 1300 / 1400). The control device may be, for example, a microcontroller unit (MCU).

[0224] In some embodiments, X full-bridge circuits in a drive circuit for a brushless motor are packaged on X chips, i.e., one full-bridge circuit is packaged on one chip. In some other embodiments, X full-bridge circuits in a drive circuit for a brushless motor are packaged on one chip.

[0225] In some embodiments, the control unit and drive circuit for the brushless motor are packaged on different chips.

[0226] In some other embodiments, the control unit and drive circuit for a brushless motor are packaged on the same chip. For example, X full-bridge circuits are packaged one-to-one on X chips, and each chip may further package one sub-control unit to control one full-bridge circuit on that chip. In this case, the control unit for the drive circuit for a brushless motor includes all the sub-control units packaged on the X chips.

[0227] In some embodiments, the drive system further includes X Hall detection elements. For example, the X Hall detection elements can be packaged on the same chip as the X full-bridge circuits. Alternatively, for example, each Hall detection element can be packaged on a single chip with a corresponding full-bridge circuit.

[0228] Figure 15A is a schematic circuit diagram of a drive system for a brushless motor based on some embodiments of the present disclosure.

[0229] As shown in Figure 15A, the drive system for the brushless motor includes a drive circuit 1501 for the brushless motor and a control device 1502 for the drive circuit for the brushless motor.

[0230] Figure 15A schematically shows that the drive circuit 1501 includes two full-bridge circuits, each full-bridge circuit containing four switches, for a total of eight switches (all of which in Figure 15A are n-type MOSFETs). These eight switches are represented as Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8, respectively.

[0231] The control device 1502 is configured to control the state of each switch Q1 to Q8 in the drive circuit 1501.

[0232] Specifically, referring to Figure 15A, the eight terminals PWM1_P, PWM2_P, PWM1_N, PWM2_N, PWM3_P, PWM4_P, PWM3_N, and PWM4_N of the control device 1502 are connected to the gates of switches Q1 through Q8, respectively. For example, terminals PWM1_P, PWM2_P, PWM1_N, and PWM2_N are connected to the gates of switches Q1, Q2, Q5, and Q6 in the first full-bridge circuit via one of the four resistors in resistor array R1, respectively, while terminals PWM3_P, PWM4_P, PWM3_N, and PWM4_N are connected to the gates of switches Q3, Q4, Q7, and Q8 in the second full-bridge circuit via one of the four resistors in resistor array R2, respectively. The control device 1502 can output pulse width modulation (PWM) signals via these eight terminals to control the state of each of the switches Q1 to Q8.

[0233] In some embodiments, the control device 1502 is further configured to control the state of each switch in the drive circuit 1501 based on the Hall detection signal.

[0234] For example, referring to Figure 15A, the control device 1502 is further connected to two Hall detection elements 1503 via terminals INT0 and INT1, respectively, so that it can acquire Hall detection signals from the Hall detection elements 1503. Each Hall detection element 1503 may include a power supply voltage terminal VCC, a ground terminal GND, and a Hall detection signal output terminal OUT.

[0235] In some embodiments, the control device 1502 is further configured to improve the reliability of the drive circuit 1501 by detecting the current and voltage of the drive circuit 1501 and ensuring that the drive circuit 1501 operates within a reliable voltage and current range.

[0236] For example, referring to Figure 15A, the control device 1502 can detect the current of the drive circuit 1501 via terminal ACC_0 and the voltage of the drive circuit 1501 via terminal ACC_1.

[0237] The drive system may further include a voltage divider circuit, which includes two resistors R3 and R4 connected in series between the input terminal VIN and the ground terminal GND of the drive circuit 1501. Terminal ACC_1 is connected to an intermediate node between resistors R3 and R4 to detect the voltage of the drive circuit 1501.

[0238] The drive system may further include a current sensing circuit 1504 shown in Figure 15A. The current sensing circuit 1504 includes an operational amplifier OA and a number of resistors R5, R6, R7, R8, R9 and R10. The operational amplifier OA includes power supply terminals VDD and VSS, a positive input terminal IN+, a negative input terminal IN-, and an output terminal OUT.

[0239] Specifically, resistor R5 is connected between node B and the ground terminal as shown in Figure 15A. One end of resistor R6 is connected to the terminal of resistor R5 that is connected to node B, and the other end is connected to the positive input terminal IN+ of operational amplifier OA. One end of resistor R7 is connected to the ground terminal of resistor R5, and the other end is connected to the negative input terminal IN- of operational amplifier OA. One end of resistor R8 is connected to the terminal of resistor R6 that is connected to the positive input terminal IN+, and the other end is grounded. One end of resistor R9 is connected to the terminal of resistor R7 that is connected to the negative input terminal IN-, and the other end is connected to the output terminal OUT of operational amplifier OA. Resistor R10 is connected between the output terminal OUT of operational amplifier OA and terminal ACC_0 of control device 1502.

[0240] As shown in Figure 15A, the drive system may further include a plurality of capacitors Cl, C2, C3 and C4, one end of which is grounded. Specifically, the other end of capacitor C1 is connected to an intermediate node between one Hall detection element 1503 and the control device 1502. The other end of capacitor C2 is connected to an intermediate node between another Hall detection element 1503 and the control device 1502. The other end of capacitor C3 is connected to an intermediate node between the current detection circuit 1504 and the control device 1502. The other end of capacitor C4 is connected to an intermediate node between the voltage divider circuit and the control device 1502.

[0241] The control device 1502 may further include other terminals, such as a signal input terminal FGRD, a signal output terminal PWM_IN, a power supply voltage terminal VCC, and a ground terminal GND, which will not be described further here.

[0242] Figure 15B is a schematic circuit diagram of a drive system for a brushless motor based on some other embodiments of the present disclosure.

[0243] I will not explain further the similarities between Figure 15B and Figure 15A. Unlike Figure 15A, switches Q1 to Q4 in Figure 15B are p-type MOSFETs.

[0244] As mentioned above, in the alternating energization method, control can be further simplified by making the waveform of the drive signal supplied to the conductor a square wave. In this case, the internal circuit of the control device 1502 is relatively simple.

[0245] Specifically, as shown in Figure 15B, the control device 1502 includes four inverters INV1, INV2, INV3, and INV4. Each Hall detection element 1503 is connected to two resistors in the corresponding resistor array via two inverters, and each Hall detection element 1503 is further directly connected to two other resistors in the corresponding resistor array.

[0246] In these implementations, the drive circuit 1501 can be controlled based on a simple internal control device 1502.

[0247] In Figures 15A and 15B, some elements are further labeled with numbers to indicate the terminal numbers of those elements. For example, the numbers 1, 2, and 3 next to the Hall detection element 1503 represent the first terminal (i.e., the power supply voltage terminal VCC), the second terminal (i.e., the output terminal OUT), and the third terminal (i.e., the ground terminal GND) of the Hall detection element 1503, respectively.

[0248] Embodiments of the present disclosure further provide a drive circuit for a brushless motor. The brushless motor includes a stator core 1, a rotor 2, and X-phase conductors 3, where X ≥ 2. The stator core 1 includes Z groups of teeth 11 spaced apart along a first circumferential direction. The rotor 2 includes a magnetic ring 21 with P poles (where P is even). The X-phase conductors 3 are wound around the groups of teeth 11 to form coils 31, where Z = P × X. In conductors 3 of the same phase, the winding directions of the coils 31 on two adjacent groups of teeth 11 along the second circumferential direction of the groups of teeth 11 are opposite and are arranged at intervals of X-1 groups of teeth 11.

[0249] Figure 16 is a schematic diagram of the structure of a drive circuit for a brushless motor based on some further different embodiments of the present disclosure.

[0250] Figure 16 shows the case where X=2. Referring to Figure 16, the drive circuit for the brushless motor includes a first half-bridge circuit 1610 and X second half-bridge circuits 1620. The first half-bridge circuit 1610 and the X second half-bridge circuits 1620 are connected in parallel between the input terminal VIN and the ground terminal GND of the drive circuit.

[0251] Each of the first half-bridge circuit 1610 and the X second half-bridge circuits 1620 includes two switches S1' and S2' connected via node P'. The switches S1' and S2' may be, for example, thyristors, MOSFETs, or IGBTs. For example, switch S1' may be one of an n-type MOSFET and a p-type MOSFET, and switch S2' may be an n-type MOSFET.

[0252] In these embodiments, the node P' of the first half-bridge circuit 1610 is configured to be connected to the first end of the X-phase conductor 3, and the node P' of the i-th second half-bridge circuit 1620 out of X second half-bridge circuits 1620 is configured to be connected to the second end of the i-th phase conductor 3, where 1 ≤ i ≤ X.

[0253] For example, referring to Figure 16, node P' of the first half-bridge circuit 1610 is connected to the first end X1-IN of the first phase conductor and to the first end X2-IN of the second phase conductor. Node P' of the first second half-bridge circuit 1620 is connected to the second end X1-OUT of the first phase conductor, and node P' of the second second half-bridge circuit 1620 is connected to the second end X2-OUT of the second phase conductor.

[0254] The drive circuit is configured to provide N periodically changing drive signals to the N-phase conductor 3 via its independent first and second ends, respectively, where 2 ≤ N ≤ X.

[0255] Here, the waveform of each drive signal in one cycle includes a first waveform with an intensity greater than 0 and a second waveform with an intensity less than 0, and within the period in which the intensity of any one drive signal in one cycle is not 0, the intensity of all other drive signals among the N drive signals is 0.

[0256] In other words, the drive circuit is configured to drive the brushless motor in an alternating energization manner by providing N drive signals to the N-phase conductor 3.

[0257] For example, by controlling switch S1' of a second half-bridge circuit 1620 to be on and switch S2' to be off, and controlling switch S1' of a first half-bridge circuit 1610 to be off and switch S2' to be on, the drive circuit can provide a first waveform with an intensity greater than 0 to the one-phase conductor to which node P' of the second half-bridge circuit 1620 is connected.

[0258] Conversely, by controlling switch S1' of a second half-bridge circuit 1620 to be off and switch S2' to be on, and controlling switch S1' of the first half-bridge circuit 1610 to be on and switch S2' to be off, the drive circuit can provide a second waveform with an intensity less than 0 to the one-phase conductor to which node P' of the second half-bridge circuit 1620 is connected.

[0259] When the number of wires X in a brushless motor is the same, the number of half-bridge circuits in the drive circuits of these embodiments is relatively small. By using such a drive circuit to drive a brushless motor with alternating current, the cost of the drive circuit and the volume of the drive circuit can be reduced.

[0260] Embodiments of the present disclosure further provide a drive device for a brushless motor of any one of the embodiments described above, and an apparatus including a brushless motor of any one of the embodiments described above.

[0261] Embodiments of the present disclosure further provide a device comprising a drive circuit for a brushless motor of any one of the above embodiments and a brushless motor of any one of the above embodiments.

[0262] Embodiments of the present disclosure further provide a drive system for a brushless motor of any one of the embodiments described above, and equipment including a brushless motor of any one of the embodiments described above.

[0263] The device in any one of the above embodiments may be, for example, a vehicle, electrical equipment (e.g., home appliances), or any other device capable of converting electrical energy into mechanical energy.

[0264] Embodiments of the present disclosure further provide a computer program product including a computer program, which, when executed by a processor, realizes a driving method for a brushless motor or a control method for a driving circuit for a brushless motor according to any one of the embodiments described above.

[0265] The embodiments of this disclosure have been described in detail above. Some details well known in the art have been omitted in order to avoid concealing the concept of this disclosure. Those skilled in the art will be able to fully understand, based on the above description, how to implement the technical inventions disclosed herein.

[0266] Each embodiment in this specification is described recursively, with each embodiment focusing on its differences from other embodiments, and any identical or similar parts between embodiments refer to one another. The embodiments of apparatus and circuits are relatively simple in description, as they fundamentally correspond to the embodiments of methods; relevant details should be referred to the description of the embodiments of methods.

[0267] Those skilled in the art should understand that the embodiments of the present disclosure can be provided as a method, system, or computer program product. Therefore, the present disclosure may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. And the present disclosure can adopt the form of a computer program product implemented on one or more computers' non-transitory storage media (including but not limited to magnetic disk memories, CD-ROMs, optical memories, etc.) containing computer-usable program codes.

[0268] The present disclosure is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present disclosure. It should be understood that the functions specified in one or more flows in the flowchart and / or one or more blocks in the block diagram can be realized by computer program instructions. By providing these computer program instructions to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, the instructions executed by the processor of the computer or other programmable data processing devices can generate an apparatus for realizing the functions specified in one or more flows of the flowchart and / or one or more blocks of the block diagram.

[0269] These computer program instructions may also be stored in a computer-readable memory that can guide a computer or other programmable data processing device to operate in a specific manner, whereby the instructions stored in this computer-readable memory include a manufactured product of an instruction device, and this instruction device realizes the functions specified in one or more flows of the flowchart and / or one or more blocks of the block diagram.

[0270] These computer program instructions may be loaded onto a computer or other programmable data processing device, thereby causing a series of operational steps to be performed on the computer or other programmable device, and thereby generating a process implemented by the computer. Thus, the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one flow or more flows of a flowchart and / or one block or more blocks of a block diagram.

[0271] Although some specific embodiments of the present disclosure have been described in detail by way of illustration, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Those skilled in the art should understand that the above embodiments can be modified or equivalent replacements can be made to some technical features without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is limited by the appended claims.

Claims

1. A drive circuit for a brushless motor, wherein the brushless motor is A stator core (1) includes Z groups of teeth (11) that are spaced apart along the first circumferential direction, A rotor (2) including a magnetic ring (21) with P poles (where P is an even number), An X-phase conductor (3) is wound around the tooth group (11) to form a coil (31), where X≧2 and Z=P×X, and in the same phase of the conductor (3), the winding direction along the second circumferential direction of the tooth group (11) of the coil (31) on two adjacent tooth groups (11) is opposite, and the X-phase conductor (3) is arranged at intervals of X-1 tooth groups (11), The aforementioned drive circuit is It includes X full-bridge circuits, each full-bridge circuit includes two half-bridge circuits connected in parallel between the input terminal and the ground terminal of the drive circuit, each half-bridge circuit includes two switches connected via a node, and the two half-bridge circuits include a first half-bridge circuit and a second half-bridge circuit, The node of the first half-bridge circuit in the i-th full-bridge circuit is configured to be connected to the first end of the i-th phase conductor, The node of the second half-bridge circuit in the i-th full-bridge circuit is configured to be connected to the second end of the i-th phase conductor, A drive circuit where 1 ≤ i ≤ X.

2. Of the X full-bridge circuits mentioned above, N full-bridge circuits are: Within one control cycle, the system is configured to provide N periodically changing drive signals to the N-phase conductor (3) via its independent first and second ends, where 1 ≤ N ≤ X. The circuit according to claim 1, wherein the waveform of each drive signal in one cycle includes a first waveform with an intensity greater than 0 and a second waveform with an intensity less than 0.

3. The circuit according to claim 2, wherein the intensity of the N drive signals within a first period band is continuously non-zero.

4. The circuit according to claim 3, wherein the time at which the first waveform and the second waveform overlap is the first time, and the intensity of each drive signal during any period other than the first time within one cycle is continuously non-zero.

5. The circuit according to claim 3, wherein the intensity of each drive signal during the second period band within one cycle is continuously 0.

6. The circuit according to claim 5, wherein the intensity of each drive signal at any time other than the second period band during one cycle is not zero.

7. The circuit according to claim 2, wherein during the period in which the intensity of any one drive signal in one cycle is not zero, the intensity of the other drive signals among the N drive signals is all zero.

8. The circuit according to claim 2, wherein the amplitudes of the N drive signals are the same.

9. The circuit according to claim 2, wherein the first waveform and the second waveform are centrally symmetrical.

10. The waveforms of the N drive signals are all square waves, or The circuit according to claim 2, wherein the first waveform and the second waveform match a sine function.

11. The brushless motor includes one or more stator cores (1), and the X-phase conductors (3) are sequentially wound around the tooth group (11) in the order of the first to the X-phase along the first circumferential direction. The N-phase conductor includes an i-th phase conductor and a k-th phase conductor, with a phase difference θ between the drive signal of the i-th phase conductor and the drive signal of the k-th phase conductor. ｉｋ It satisfies the following equation, [Math 1] 1 ≤ i < k ≤ X, The circuit according to claim 2, wherein in the same stator core (1), the group of teeth (11) of the X-phase conductor and the adjacent groups of teeth (11) on both sides each have a gap at the closest position, the gap has a central position in the first circumferential direction, and in all the gaps formed by the Z groups of teeth (11), the central angle corresponding to the arc between the central position of the X-phase conductor and the first adjacent central position in the circumferential direction is βx, and the sector area corresponding to the arc includes at least some of the group of teeth (11) of the X-phase conductor.

12. The circuit according to claim 1, wherein each half-bridge circuit includes two switches: a first switch connected to the input terminal of the drive circuit and a second switch connected to the ground terminal of the drive circuit, the first switch being one of an n-type metal oxide semiconductor MOSFET and a p-type MOSFET, and the second switch being an n-type MOSFET.

13. The process includes the step of providing N periodically changing drive signals to the N-phase conductors (3) via the independent first and second ends of each of the N-phase conductors (3) of the N-phase conductors (3) of the X-phase conductors, by controlling the switching on one switch in the first half-bridge circuit and one switch in the second half-bridge circuit of each of the N-phase conductors (3) of the X-phase conductors within one control cycle, 1 ≤ N ≤ X A method for controlling a drive circuit for a brushless motor according to any one of claims 1 to 12, wherein the waveform of each drive signal in one cycle includes a first waveform with an intensity greater than 0 and a second waveform with an intensity less than 0.

14. The steps include determining the first amplitude of the N-phase conductor and each drive signal based on the target torque of the rotor (2), The method according to claim 13, further comprising the step of determining a first frequency of each drive signal based on the target rotational speed of the rotor (2).

15. The method according to claim 14, wherein N = X when the target torque is higher than a first preset torque.

16. The method according to claim 15, wherein the first amplitude of the N drive signals is the same when the target torque is higher than the first preset torque.

17. If the target torque is lower than the second preset torque, N < X, and the first amplitudes of the N drive signals are the same, or The method according to claim 14, wherein N = X, and the first amplitudes of at least two of the N drive signals are different.

18. From multiple sets of parameters, one set of parameters is selected to reach the demands for the target rotational speed and the target torque, wherein the set of parameters represents the second frequency and second amplitude of each drive signal, and The method according to claim 14, wherein the first frequency and the first amplitude of each drive signal are determined based on the set of parameters.

19. A control device for a drive circuit for a brushless motor according to any one of claims 1 to 12, The control module is configured to provide N periodically changing drive signals to the N-phase conductors (3) via the independent first and second ends of each of the N-phase conductors (3) of the N-phase conductors (3) of the X-phase conductors, by controlling the switching on of one switch in the first half-bridge circuit and one switch in the second half-bridge circuit of each of the N-phase conductors of the X-phase conductors within one control cycle, 1 ≤ N ≤ X, A control device for a drive circuit, wherein the waveform of each drive signal in one cycle includes a first waveform with an intensity greater than 0 and a second waveform with an intensity less than 0.

20. A control device for a drive circuit for a brushless motor according to any one of claims 1 to 12, Memory and A control device comprising: a processor coupled to the memory, configured to execute the control method according to any one of claims 13 to 18 based on instructions stored in the memory.

21. A drive system for a brushless motor, A drive circuit for a brushless motor according to any one of claims 1 to 12, A drive system comprising a control device for a drive circuit for a brushless motor according to claim 19 or 20.

22. The system according to claim 21, wherein the X full-bridge circuits are packaged on a single chip.

23. The control device is packaged on the chip. The system according to claim 22.

24. It is a device, A drive system for a brushless motor according to any one of claims 21 to 23, Apparatus including the aforementioned brushless motor.

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