High-speed operation compensation method, system and brushless DC motor of brushless DC motor

Abstract

The present invention relates to a method and system for compensating high-speed operation of a brushless DC motor, and a brushless DC motor, comprising the following steps: obtaining a detection signal; determining whether the detection signal has changed; if so, performing delay compensation, and after the delay compensation is completed, performing a step of determining whether a commutation condition is satisfied; if not, determining whether the commutation condition is satisfied; if the commutation condition is satisfied, determining the operating state of the brushless DC motor; and performing commutation based on the operating state of the brushless DC motor. The present invention performs delay compensation when the brushless DC motor is operating at high speed, and determines the commutation moment based on the delay time point, thereby achieving the purpose of early commutation, avoiding commutation lag, and effectively improving the high-speed performance of the brushless DC motor.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and more particularly to a high-speed operation compensation method and system for a brushless DC motor and the brushless DC motor. Background Art

[0002] For brushless DC motors with Hall sensors, the driving scheme is relatively simple. The conventional scheme is to drive the motor by detecting the Hall signal and turning on the corresponding motor phase according to the Hall signal by the controller.

[0003] Hall effect signals are usually detected by reading IO ports or setting capture interrupts. However, no matter which method is used, there will be a detection lag problem. Especially at high speeds, the same lag time corresponds to a larger position angle, and the lag time can reach a sampling period or even longer, seriously affecting the high-speed performance of the motor. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a high-speed operation compensation method and system for a brushless DC motor and a brushless DC motor in view of the defects of the prior art.

[0005] The technical solution adopted by the present invention to solve the technical problem is to construct a high-speed operation compensation method for a brushless DC motor, comprising the following steps:

[0006] Get detection signal;

[0007] Determining whether the detection signal changes;

[0008] If so, delay compensation is performed, and after the delay compensation is completed, the step of determining whether the commutation condition is met is executed;

[0009] If not, determine whether the commutation conditions are met;

[0010] If the commutation conditions are met, the operating state of the brushless DC motor is determined;

[0011] Phase commutation is performed according to the operating state of the brushless DC motor.

[0012] In the high-speed operation compensation method of the brushless DC motor of the present invention, determining whether the detection signal changes includes:

[0013] Determine whether the detection signal changes from a high level to a low level;

[0014] Alternatively, it is determined whether the detection signal changes from a low level to a high level.

[0015] In the high-speed operation compensation method of the brushless DC motor of the present invention, if yes, performing delay compensation includes:

[0016] If the detection signal changes, obtaining a first count value;

[0017] Assigning the value of the first count value to the second count value, and clearing the first count value to zero;

[0018] determining whether the second count value is greater than a third count value;

[0019] If not, set the high-speed flag to 1;

[0020] If so, determining whether the second count value is greater than a fourth count value;

[0021] If the second count value is greater than the fourth count value, resetting the high-speed flag bit;

[0022] Determine whether the high-speed flag is currently set;

[0023] If the high-speed flag is currently set, performing delay compensation according to the second count value;

[0024] If the high-speed flag is not currently set, no delay compensation is performed.

[0025] In the high-speed operation compensation method of the brushless DC motor of the present invention, the method further includes:

[0026] If the second count value is less than the fourth count value, the step of determining whether the high-speed flag is currently set is executed.

[0027] In the high-speed operation compensation method of the brushless DC motor of the present invention, performing delay compensation according to the second count value includes:

[0028] comparing the second count value with a sixth count value;

[0029] If the second count value is greater than or equal to the sixth count value, then calculating and determining the value of the fifth count value in the first manner;

[0030] If the second count value is smaller than the sixth count value, the value of the fifth count value is determined by calculating in a second manner.

[0031] In the high-speed operation compensation method for a brushless DC motor according to the present invention, the determination of whether the commutation condition is satisfied comprises:

[0032] Get a first count value;

[0033] Determining whether the first count value is greater than or equal to a fifth count value;

[0034] If so, the commutation condition is met;

[0035] If not, the commutation condition is not met.

[0036] In the high-speed operation compensation method of the brushless DC motor of the present invention, if the commutation condition is satisfied, determining the operating state of the brushless DC motor includes:

[0037] Get the high-speed flag;

[0038] Determine whether the high-speed flag is set;

[0039] If not, it is determined that the brushless DC motor is in a low-speed operation state;

[0040] If so, it is determined that the brushless DC motor is in a high-speed operation state.

[0041] In the high-speed operation compensation method of the brushless DC motor of the present invention, the commutation according to the operating state of the brushless DC motor includes:

[0042] If the brushless DC motor is in a low-speed operation state, commutating according to the detection signal;

[0043] If the brushless DC motor is in a high-speed operation state, the phase is commutated one step in advance according to the detection signal.

[0044] The present invention also provides a high-speed operation compensation system for a brushless DC motor, comprising:

[0045] an acquisition unit, configured to acquire a detection signal;

[0046] A first judging unit, configured to judge whether the detection signal changes;

[0047] a compensation unit, configured to perform delay compensation when the detection signal changes, and to determine whether a commutation condition is met after the delay compensation is completed;

[0048] a second judging unit, configured to judge whether a commutation condition is satisfied when the detection signal does not change;

[0049] a state determination unit, for determining the operating state of the brushless DC motor when a commutation condition is met;

[0050] A commutation unit is used to perform commutation according to the operating state of the brushless DC motor.

[0051] The present invention also provides a brushless DC motor, comprising the high-speed operation compensation system of the brushless DC motor described above.

[0052] The high-speed operation compensation method, system, and brushless DC motor of the present invention have the following beneficial effects: comprising the following steps: obtaining a detection signal; determining whether the detection signal has changed; if so, performing delay compensation, and after the delay compensation is completed, performing a step of determining whether a commutation condition is satisfied; if not, determining whether the commutation condition is satisfied; if the commutation condition is satisfied, determining the operating state of the brushless DC motor; and performing commutation based on the operating state of the brushless DC motor. The present invention performs delay compensation when the brushless DC motor is operating at high speed, and determines the commutation moment based on the delay time point, thereby achieving the purpose of early commutation, avoiding commutation lag, and effectively improving the high-speed performance of the brushless DC motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0054] Figure 1 1 is a flow chart of a first embodiment of a high-speed operation compensation method for a brushless DC motor provided by the present invention;

[0055] Figure 2 1 is a flow chart of a second embodiment of a high-speed operation compensation method for a brushless DC motor provided by the present invention;

[0056] Figure 3 1 is a flow chart of a third embodiment of the high-speed operation compensation method for a brushless DC motor provided by the present invention;

[0057] Figure 4 1 is a schematic structural diagram of a high-speed operation compensation system for a brushless DC motor provided by an embodiment of the present invention;

[0058] Figure 5 This is a schematic diagram of the Hall signal of a three-phase brushless DC motor;

[0059] Figure 6 It is the space vector diagram of the brushless DC motor driven by two-two conduction;

[0060] Figure 7 It is the current direction diagram corresponding to the signal at different positions. DETAILED DESCRIPTION

[0061] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0062] In order to solve the hysteresis problem caused by the phase change when the existing brushless DC motor is running at high speed after detecting the jump of the Hall signal, the present invention provides a high-speed operation compensation method of the brushless DC motor. The high-speed operation compensation method can perform a delay compensation operation when the Hall signal jump is detected, so that the phase change is performed in advance at the next jump, effectively solving the hysteresis problem and improving the high-speed performance of the brushless DC motor.

[0063] Specifically, such as Figure 1 FIG. 1 is a flow chart of an optional embodiment of a high-speed operation compensation method for a brushless DC motor provided by the present invention.

[0064] like Figure 1 As shown, the high-speed operation compensation method of the brushless DC motor includes the following steps:

[0065] Step S10: Acquire a detection signal.

[0066] Optionally, in an embodiment of the present invention, the detection signal is a Hall signal. The Hall signal can be obtained using conventional methods, and the present invention does not specifically limit this.

[0067] Step S20: Determine whether the detection signal changes.

[0068] In some embodiments, determining whether the detection signal changes includes: determining whether the detection signal changes from a high level to a low level; or determining whether the detection signal changes from a low level to a high level.

[0069] Specifically, it is determined whether the detection signal has changed, that is, whether the Hall signal has jumped, that is, whether the Hall signal has jumped from a high level to a low level, or whether the Hall signal has jumped from a low level to a high level. As long as the Hall signal jumps from a high level to a low level or from a low level to a high level, it can be determined that the Hall signal has jumped.

[0070] Among them, the schematic diagram of the Hall signal change of the three-phase brushless DC motor is as follows Figure 5 As shown in the figure, HallA represents the Hall signal corresponding to phase A, HallB represents the Hall signal corresponding to phase B, and HallC represents the Hall signal corresponding to phase C.

[0071] Step S30: If yes, perform delay compensation, and after the delay compensation is completed, perform the step of determining whether the commutation condition is met.

[0072] In some embodiments, such as Figure 2 If so, delay compensation includes the following steps:

[0073] Step S201: If the detection signal changes, obtain a first count value.

[0074] Optionally, in an embodiment of the present invention, the first count value is the number of detections recorded after the most recent Hall signal jump.

[0075] Step S202: Assign the value of the first count value to the second count value, and clear the first count value to zero.

[0076] Optionally, in an embodiment of the present invention, the second count value is the number of detections between two Hall signal transitions.

[0077] Step S203: Determine whether the second count value is greater than the third count value.

[0078] Optionally, in an embodiment of the present invention, the third count value is a determination value for entering high-speed mode. It should be noted that the position angle corresponding to each two Hall signal changes is 60° electrical angle, and the smaller the second count value, the higher the corresponding speed. In an embodiment of the present invention, the third count value can be set to 8.

[0079] Step S204: If not, set the high-speed flag.

[0080] The high-speed flag is used to indicate the operating status of the brushless DC motor. When the high-speed flag is set to 1, the brushless DC motor is in high-speed operation; when the high-speed flag is set to 0, the brushless DC motor is in low-speed operation. A high-speed flag set to 1 indicates high-speed flag status, while a reset high-speed flag set to 0 indicates high-speed flag status.

[0081] Step S205: If yes, determine whether the second count value is greater than the fourth count value.

[0082] Step S206: If the second count value is greater than the fourth count value, the high-speed flag is reset.

[0083] Optionally, in an embodiment of the present invention, the fourth count value represents the judgment value for exiting the high-speed mode. As can be seen from the above, the smaller the second count value is, the fewer the detection counts between the two Hall signal jumps are, and the higher the speed represented is. Therefore, in an embodiment of the present invention, the third count value is set to 8, and the fourth count value can be set to 12. When the second count value is less than the third count value, it means that the speed is high. At this time, the high-speed flag position can be set to 1; when the second count value is greater than the fourth count value, it means that the speed is low, and the high-speed flag position can be set to 0; when the second count value is between the third count value and the fourth count value, the high-speed flag position remains unchanged. Among them, when the second count value is between the third count value and the fourth count value, by keeping the high-speed flag position unchanged, frequent switching of the high-speed flag can be prevented.

[0084] Furthermore, if the second count value is smaller than the fourth count value, the process proceeds to step 207 .

[0085] Step S207: Determine whether the high-speed flag is currently set.

[0086] Step S208: If the high-speed flag is currently set, delay compensation is performed according to the second count value.

[0087] In some embodiments, performing delay compensation based on the second count value includes: comparing the second count value with a sixth count value; if the second count value is greater than or equal to the sixth count value, calculating and determining the value of the fifth count value using a first method; and if the second count value is less than the sixth count value, calculating and determining the value of the fifth count value using a second method. The sixth count value may be 5.

[0088] Optionally, in an embodiment of the present invention, the fifth count value is a count between the Hall signal jumping to the switching conduction phase (i.e., commutation).

[0089] Specifically, if the second count value is greater than or equal to the sixth count value, the fifth count value satisfies the following formula:

[0090] N5=N2-2(1).

[0091] Wherein, N5 represents the fifth count value, and N2 represents the second count value.

[0092] If the second count value is less than the sixth count value, the fifth count value satisfies the following formula:

[0093] N5=N2 / 2(2).

[0094] Specifically, when the high-speed flag is currently set, that is, the high-speed flag is 1, it means that the brushless DC current is in a high-speed operation state. Therefore, after the value of N5 is calculated by formula (1) or formula (2), a delay operation can be performed based on N5, and high-speed commutation is performed when N5 is reached, thereby achieving the purpose of early commutation and avoiding the occurrence of lag problems.

[0095] Step S209: If the high-speed flag is not currently set, no delay compensation is performed.

[0096] Specifically, if the high-speed flag is not currently set, that is, the high-speed flag is 0, it means that the brushless DC motor is in a low-speed operation mode, and therefore delay compensation is not required.

[0097] Step S40: If not, determine whether the commutation condition is met.

[0098] In some embodiments, if not, determining whether the commutation condition is met includes: obtaining a first count value; determining whether the first count value is greater than or equal to a fifth count value; if so, the commutation condition is met; if not, the commutation condition is not met.

[0099] Specifically, if the commutation condition is met, the process proceeds to step S50; if the commutation condition is not met, the process ends.

[0100] Step S50: If the commutation condition is met, determine the operating state of the brushless DC motor.

[0101] In some embodiments, if the commutation condition is met, determining the operating state of the brushless DC motor includes: obtaining a high-speed flag; determining whether the high-speed flag is set; if not, determining that the brushless DC motor is in a low-speed operating state; if so, determining that the brushless DC motor is in a high-speed operating state.

[0102] Specifically, if the current high-speed flag is 1, it is determined that the brushless DC motor is in a high-speed operation state; if the current high-speed flag is 0, it is determined that the brushless DC motor is in a low-speed operation state.

[0103] Step S60: performing phase commutation according to the operating state of the brushless DC motor.

[0104] In some embodiments, commutating according to the operating state of the brushless DC motor includes: if the brushless DC motor is in a low-speed operating state, commutating according to a detection signal; if the brushless DC motor is in a high-speed operating state, commutating one step in advance according to the detection signal.

[0105] When the BLDC motor is running at low speed, commutation is performed based on the current Hall signal in Table 1. When the BLDC motor is running at high speed, commutation is performed based on the current Hall signal in Table 2. Table 1 shows the correspondence between Hall signals and conduction, while Table 2 is a step ahead of Table 1.

[0106] Specific as Figure 6 and Figure 7 As shown, Figure 6 The space vector diagram of the brushless DC motor driven by two-two conduction, Figure 7 It is the current direction diagram corresponding to the signal at different positions.

[0107] Figure 6 The AB vector represents the current flowing from phase A to phase B. The specific motor winding connection method and current direction are as follows: Figure 7 As shown, clockwise rotation (ABC, in Figure 6For counterclockwise rotation (CBA, clockwise in the figure), the Hall signals and corresponding conduction phases are 5(AB), 4(AC), 6(BC), 2(BA), 3(CA), and 1(CB). For counterclockwise rotation (CBA, clockwise in the figure), the Hall signals and corresponding conduction phases are 5(BA), 1(BC), 3(AC), 2(AB), 6(CB), and 4(CA). The above conduction phases and Hall signals are shown in Table 1. Table 2 is a step ahead, with clockwise rotation being 1(AB), 5(AC), 4(BC), 6(BA), 2(CA), and 3(CB); for counterclockwise rotation being 4(BA), 5(BC), 1(AC), 3(AB), 2(CB), and 6(CA).

[0108] In a specific embodiment, Figure 3 As shown, the high-speed operation compensation method of the brushless DC motor includes:

[0109] Step S301: Acquire Hall signal.

[0110] Step S302: Determine whether the Hall signal changes.

[0111] Step S303: If yes, assign N1 to N2 and clear N1.

[0112] Step S304: Determine whether N2 is greater than N3.

[0113] Step S305: If N2 is less than N3, the high-speed flag is set.

[0114] Step S306: If N2 is greater than N3, determine whether N2 is greater than N4; if N2 is less than N4, execute step S308.

[0115] Step S307: If N2 is greater than N4, the high-speed flag is reset.

[0116] Step S308: Determine whether the high-speed flag is set.

[0117] Step S309: If the high-speed flag is not set, set N5 to 0 and proceed to step S312.

[0118] Step S310: If the high-speed flag is set, set N5 according to N2 and go to step S312.

[0119] Step S311: If the Hall signal does not change, perform N1 accumulation.

[0120] Step S312: Determine whether N1 is greater than or equal to N5.

[0121] Step S313: If N1 is greater than or equal to N5, determine whether the high-speed flag is set.

[0122] Step S314: If the high-speed flag is not set, the phase is changed according to the Hall signal.

[0123] Step S315: If the high-speed flag is set, the phase is switched one step ahead according to the Hall signal.

[0124] refer to Figure 4 , which is a structural diagram of an optional embodiment of the high-speed operation compensation system of the brushless DC motor provided by the present invention.

[0125] The high-speed operation compensation system of the brushless DC motor can adopt the high-speed operation compensation method of the brushless DC motor disclosed in the embodiment of the present invention to perform high-speed operation compensation.

[0126] Specifically, such as Figure 4 As shown, the high-speed operation compensation system of the brushless DC motor includes:

[0127] The acquisition unit 401 is configured to acquire a detection signal.

[0128] The first judging unit 402 is configured to judge whether the detection signal changes.

[0129] The compensation unit 403 is configured to perform delay compensation when the detection signal changes, and to perform a step of determining whether a commutation condition is satisfied after the delay compensation is completed.

[0130] The second judging unit 404 is configured to judge whether a commutation condition is satisfied when the detection signal does not change.

[0131] The state determination unit 405 is configured to determine the operating state of the brushless DC motor when the commutation condition is met.

[0132] The commutation unit 406 is configured to perform commutation according to the operating state of the brushless DC motor.

[0133] The present invention also provides a brushless DC motor, comprising the high-speed operation compensation system of the brushless DC motor disclosed in an embodiment of the present invention.

[0134] When the brushless DC motor of the present invention runs at high speed, the commutation time is determined in advance according to the Hall signal, and commutation is performed according to the determined commutation time, thereby avoiding commutation lag and significantly improving the high-speed performance of the brushless DC motor.

[0135] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0136] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0137] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0138] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the present invention and implement it accordingly. They are not intended to limit the scope of protection of the present invention. All equivalent variations and modifications within the scope of the claims of the present invention are intended to be covered by the claims of the present invention.

Claims

1. A high-speed operation compensation method for a brushless DC motor, characterized in that: The following steps are involved: Get detection signal; Determining whether the detection signal changes; If so, delay compensation is performed, and after the delay compensation is completed, the step of determining whether the commutation condition is met is executed; If so, performing delay compensation includes: if the detection signal changes, obtaining a first count value; the first count value is used to record the number of detections after the most recent Hall signal jump; assigning the value of the first count value to a second count value, and clearing the first count value to zero; the second count value is used to represent the number of detections between two Hall signal jumps; judging whether the second count value is greater than a third count value; the third count value is a determination value for entering high-speed mode; if not, setting a high-speed flag; if so, judging whether the second count value is greater than a fourth count value; the fourth count value represents a determination value for exiting high-speed mode; if the second count value is greater than the fourth count value, resetting the high-speed flag; judging whether the high-speed flag is currently set; if the high-speed flag is currently set, performing delay compensation according to the second count value; if the high-speed flag is not currently set, not performing delay compensation; If not, determine whether the commutation conditions are met; If the commutation conditions are met, the operating state of the brushless DC motor is determined; Phase commutation is performed according to the operating state of the brushless DC motor.

2. The high-speed operation compensation method of a brushless DC motor according to claim 1, characterized in that: Determining whether the detection signal changes includes: Determine whether the detection signal changes from a high level to a low level; Alternatively, it is determined whether the detection signal changes from a low level to a high level.

3. The high-speed operation compensation method of a brushless DC motor according to claim 1, characterized in that: The method further comprises: If the second count value is less than the fourth count value, the step of determining whether the high-speed flag is currently set is executed.

4. The high-speed operation compensation method of a brushless DC motor according to claim 1, characterized in that: The performing delay compensation according to the second count value includes: comparing the second count value with a sixth count value; If the second count value is greater than or equal to the sixth count value, the fifth count value is calculated and determined in the first manner; the fifth count value is the count between the Hall signal jumping to the switching conduction phase; the sixth count value is 5; If the second count value is smaller than the sixth count value, the value of the fifth count value is determined by calculating in a second manner.

5. The high-speed operation compensation method of a brushless DC motor according to claim 1, characterized in that: If not, determining whether the commutation condition is met includes: Obtain a first count value; the first count value is the number of detections after the most recent Hall signal jump; Determine whether the first count value is greater than or equal to a fifth count value; the fifth count value is the count between the Hall signal jumping to the switching conduction phase; If so, the commutation condition is met; If not, the commutation condition is not met.

6. The high-speed operation compensation method of a brushless DC motor according to claim 5, characterized in that: If the commutation condition is met, determining the operating state of the brushless DC motor includes: Get the high-speed flag; Determine whether the high-speed flag is set; If not, it is determined that the brushless DC motor is in a low-speed operation state; If so, it is determined that the brushless DC motor is in a high-speed operation state.

7. The high-speed operation compensation method of a brushless DC motor according to claim 1, characterized in that: The commutating according to the operating state of the brushless DC motor includes: If the brushless DC motor is in a low-speed operation state, commutating according to the detection signal; If the brushless DC motor is in a high-speed operation state, the phase is commutated one step in advance according to the detection signal.

8. A high-speed operation compensation system for a brushless DC motor, characterized in that: include: an acquisition unit, configured to acquire a detection signal; A first judging unit, configured to judge whether the detection signal changes; A compensation unit is configured to perform delay compensation when the detection signal changes, and to perform a step of determining whether a commutation condition is met after the delay compensation is completed; the compensation unit is specifically configured to: if the detection signal changes, obtain a first count value; the first count value is used to record the number of detections after the most recent Hall signal jump; assign the value of the first count value to a second count value, and clear the first count value to zero; the second count value is used to determine the number of detections between two Hall signal jumps; determine whether the second count value is greater than a third count value; the third count value is a determination value for entering a high-speed mode; if not, set a high-speed flag; if so, determine whether the second count value is greater than a fourth count value; the fourth count value indicates a determination value for exiting a high-speed mode; if the second count value is greater than the fourth count value, reset the high-speed flag; determine whether the high-speed flag is currently set; if the high-speed flag is currently set, perform delay compensation according to the second count value; if the high-speed flag is not currently set, do not perform delay compensation; a second judging unit, configured to judge whether a commutation condition is satisfied when the detection signal does not change; a state determination unit, for determining the operating state of the brushless DC motor when a commutation condition is met; A commutation unit is used to perform commutation according to the operating state of the brushless DC motor.

9. A brushless DC motor, characterized in that: A high-speed operation compensation system for a brushless DC motor comprising the brushless DC motor according to claim 8.

Images