EP-4738688-A1 - DRIVING CIRCUIT FOR BRUSHLESS ELECTRIC MOTOR, CONTROL METHOD AND APPARATUS THEREFOR, AND DEVICE

EP4738688A1EP 4738688 A1EP4738688 A1EP 4738688A1EP-4738688-A1

Abstract

The present disclosure relates to the technical field of electric motor driving. Provided are a driving circuit for a brushless electric motor, a control method and apparatus therefor, and a device. The brushless electric motor comprises: a stator iron core, which comprises Z tooth groups arranged at intervals in a circumferential direction; a rotor, wherein the number of poles of a magnetic ring is P; and wires of X phases, which are wound around the tooth groups to form coils, wherein X ≥ 2, Z=P×X, and in wires of the same phase, the winding directions of coils on two adjacent tooth groups in the circumferential direction of the tooth groups are opposite, and the tooth groups are spaced apart by X-1 tooth groups. The driving circuit comprises: X full-bridge circuits, wherein each full-bridge circuit comprises two half-bridge circuits connected in parallel between an input end and a grounding end of the driving circuit, each half-bridge circuit comprises two switches connected by means of a node, the two half-bridge circuits comprise first and second half-bridge circuits, a node of a first half-bridge circuit in an i-th full-bridge circuit is connected to a first end of a wire of an i-th phase, and a node of a second half-bridge circuit in the i-th full-bridge circuit is connected to a second end of the wire of the i-th phase.

Inventors

ZHANG, PING
WU, Sin Hin
SUN, Xinglin
ZHOU, Huizhu
SUN, Yelin
LUO, Lanying

Assignees

Xuxin Technology (Shenzhen) Group Co., Ltd

Dates

Publication Date: 20260506
Application Date: 20240511

Claims (20)

A driving circuit for a brushless motor, wherein the brushless motor comprises: a stator core (1), comprising Z tooth groups (11) spaced apart from each other in a first circumferential direction; a rotor (2), comprising a magnetic ring (21) having a pole number P, P being an even number; and X phase wires (3), wound on the tooth groups (11) to form coils (31), X≥2, and Z=P×X, wherein in each of the phase wires (3), the coils (31) on two neighboring tooth groups (11) have opposite winding directions in a second circumferential direction of the tooth groups (11), and are spaced apart by X-1 tooth groups (11), the driving circuit comprises: X full-bridge circuit, each comprising two half-bridge circuits connected in parallel between an input terminal and a ground terminal of the driving circuit, each of the half-bridge circuits comprising two switches connected by a node, and the two half-bridge circuits comprising a first half-bridge circuit and a second half-bridge circuit, wherein the node of the first half-bridge circuit in an i th full-bridge circuit is configured for connecting to a first end of an i th phase wire, the node of the second half-bridge circuit in the i th full-bridge circuit is configured for connecting to a second end of the i th phase wire, and 1≤i≤X.
The circuit of claim 1, wherein N full-bridge circuits among the X full-bridge circuits are configured for: providing N periodically varying drive signals to N phase wires (3) through first ends and second ends, which are independent of each other, of the N phase wires (3) in a control period, wherein 1≤N≤X, a waveform of each drive signal in one period comprises a first waveform with an intensity greater than 0 and a second waveform with an intensity less than 0.
The circuit of claim 2, wherein intensities of the N drive signals are always not 0 in a first time interval.
The circuit of claim 3, wherein a moment at which the first waveform and the second waveform overlap is a first moment, and the intensity of each drive signal is always not 0 in any time interval other than the first moment in one period.
The circuit of claim 3, wherein the intensity of each drive signal is always 0 in a second time interval in one period.
The circuit of claim 5, wherein the intensity of each drive signal is not 0 at any moment in one period except for the second time interval.
The circuit of claim 2, wherein in a time interval within one period in which any one of the N drive signals has an intensity which is not 0, the rest of the N drive signals have an intensity of 0.
The circuit of claim 2, wherein the N drive signals have the same amplitude.
The circuit of claim 2, wherein the first waveform is centrosymmetric to the second waveform.
The circuit of claim 2, wherein: waveforms of the N drive signals are square waves; or the first waveform and the second waveform conform to a sine function.
The circuit of claim 2, wherein the brushless motor comprises one or more stator cores (1), and the X phase wires (3) are wound on the tooth groups (11) in the first circumferential direction in an order from a 1 st phase wire to an X th phase wire; the N phase wires comprise an i th phase wire and a k th phase wire, and a phase difference between a drive signal of the i th phase wire and a drive signal of the k th phase wire is θ ik = P 2 ∑ i k − 1 β X , wherein 1≤i<k≤X; and in each of the one or more stator cores (1), a spacing exists between the tooth group (11) of an x th phase wire and each of neighboring tooth groups (11) on two sides of the tooth group (11) of the x th phase wire, the spacing has a center position in the first circumferential direction, and among all the spacings formed between the Z tooth groups (11), a central angle corresponding to an arc between the center position of the x th phase wire and each of the center positions neighboring to the center position of the x th phase wire in the first circumferential direction is β X , and a sector corresponding to the arc comprises at least a part of the tooth group (11) of the x th phase wire.
The circuit of claim 1, wherein the two switches of each half-bridge circuit comprise a first switch connected to the input terminal of the driving circuit and a second switch connected to the ground terminal of the driving circuit, the first switch is one of a n-type metal-oxide-semiconductor field effect transistor, MOSFET, and a p-type MOSFET, and the second switch is an n-type MOSFET.
A method for controlling the driving circuit for a brushless motor of any one of claims 1 to 12, comprising: controlling, in a control period, a switch in a first half-bridge circuit and a switch in a second half-bridge circuit of each of N full-bridge circuits among the X full-bridge circuits to turn on, such that the N full-bridge circuits provide periodically varying N drive signals to N phase wires (3) through respective first and second ends, which are independent of each other, of the N phase wires (3), wherein 1≤N≤X, a waveform of each drive signal in one period comprises a first waveform with an intensity greater than 0 and a second waveform with an intensity less than 0.
The method of claim 13, further comprising: determining the N phase wires and a first amplitude of each of the drive signals according to a target torque of the rotor (2); and determining a first frequency of each of the drive signals according to a target rotational speed of the rotor (2).
The method of claim 14, wherein when the target torque is higher than a first preset torque, N=X.
The method of claim 15, wherein when the target torque is higher than the first preset torque, the first amplitudes of the N drive signals are the same.
The method of claim 14, wherein when the target torque is lower than a second preset torque, N<X, and the first amplitudes of the N drive signals are the same; or N=X, and at least two of the N drive signals have different first amplitudes.
The method of claim 14, wherein the method further comprises: calling a set of parameters required to achieve the target rotational speed and the target torque from a plurality of sets of parameters, wherein the set of parameters represents a second frequency and a second amplitude of each of the drive signals; and determining the first frequency and the first amplitude of each of the drive signals according to the set of parameters.
An apparatus for controlling the driving circuit for a brushless motor of any one of claims 1 to 12, comprising: a control module, configured for controlling, in a control period, a switch in a first half-bridge circuit and a switch in a second half-bridge circuit of each of N full-bridge circuits among the X full-bridge circuits to turn on, such that the N full-bridge circuits provide periodically varying N drive signals to N phase wires (3) through respective first and second ends, which are independent of each other, of the N phase wires (3), wherein 1≤N≤X, a waveform of each drive signal in one period comprises a first waveform with an intensity greater than 0 and a second waveform with an intensity less than 0.
An apparatus for controlling the driving circuit for a brushless motor of any one of claims 1 to 12, comprising: a memory; and a processor coupled to the memory and configured for running instructions stored in the memory to execute the method of any one of claims 13 to 18.

Description

TECHNICAL FIELD The present disclosure relates to the technical field of motor driving, and in particular to a driving circuit for a brushless motor, a control method and apparatus therefor, and a device. BACKGROUND Brushless direct current (DC) motors have the advantages of conventional DC motors while eliminating the carbon brush and slip ring structures, and can run at low speed and high power. Brushless DC motors have been widely used in the fields such as electrical servo drive, information processing, transportation, household appliances, consumer electronics, and national defense due to small size, light weight, good stability, and high efficiency. A commonly used brushless DC motor is single-phase brushless DC motor, which has the characteristics of small size and simple control. Another commonly used brushless DC motor is three-phase brushless DC motor, which has the characteristics of long service life, low noise, flexible driving modes, and mature industrial chain technology and can be applied to a wide range of scenarios including various civilian products and military products. In addition, due to wide speed regulation range, small size, high efficiency, and small steady-state speed error, three-phase brushless DC motors also have advantages in the field of speed regulation. Three-phase brushless DC motors adopt a UVW three-phase winding and a corresponding magnetic ring layout design. There are two wiring modes for the three-phase winding: star configuration and delta configuration. Using an electric motor as an example, a driver program is used to sequentially energize the phases of a three-phase winding to produce a rotating magnetic field to drive a rotor provided with a magnetic ring to rotate. SUMMARY In view of the above, the present disclosure provides the following schemes for driving a brushless motor by simple control to provide a large torque. In accordance with one aspect of the present disclosure, an embodiment provides a driving circuit for a brushless motor. The brushless motor includes: a stator core, including Z tooth groups spaced apart from each other in a first circumferential direction; a rotor, including a magnetic ring having a pole number P, P being an even number; and X phase wires, wound on the tooth groups to form coils, X≥2, and Z=P×X, where in each of the phase wires, the coils on two neighboring tooth groups have opposite winding directions in a second circumferential direction of the tooth groups, and are spaced apart by X-1 tooth groups; the driving circuit includes: X full-bridge circuit, each including two half-bridge circuits connected in parallel between an input terminal and a ground terminal of the driving circuit, each of the half-bridge circuits including two switches connected by a node, and the two half-bridge circuits including a first half-bridge circuit and a second half-bridge circuit, where the node of the first half-bridge circuit in an ith full-bridge circuit is configured for connecting to a first end of an ith phase wire, the node of the second half-bridge circuit in the ith full-bridge circuit is configured for connecting to a second end of the ith phase wire, and 1≤i≤X. In some embodiments, N full-bridge circuits among the X full-bridge circuits are configured for: providing N periodically varying drive signals to N phase wires through first ends and second ends, which are independent of each other, of the N phase wires in a control period, where 1≤N≤X, a 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. In some embodiments, intensities of the N drive signals are always not 0 in a first time interval. In some embodiments, a moment at which the first waveform and the second waveform overlap is a first moment, and the intensity of each drive signal is always not 0 in any time interval other than the first moment in one period. In some embodiments, the intensity of each drive signal is always 0 in a second time interval in one period. In some embodiments, the intensity of each drive signal is not 0 at any moment in one period except for the second time interval. In some embodiments, in a time interval within one period in which any one of the N drive signals has an intensity which is not 0, the rest of the N drive signals have an intensity of 0. In some embodiments, the N drive signals have the same amplitude. In some embodiments, the first waveform is centrosymmetric to the second waveform. In some embodiments, waveforms of the N drive signals are square waves; or the first waveform and the second waveform conform to a sine function. In some embodiments, the brushless motor includes one or more stator cores, and the X phase wires are wound on the tooth groups in the first circumferential direction in an order from a 1st phase wire to an Xth phase wire; the N phase wires include an ith phase wire and a kth phase wire, and a phase difference