WO2023078017A1 - Control system for reducing square-wave-operating torque ripple of brushless direct-current motor - Google Patents

Abstract

The present invention belongs to the technical field of brushless direct-current motors, and in particular relates to a control system for reducing a square-wave-operating torque ripple of a brushless direct-current motor. The control system comprises a brushless direct-current motor, a BLDCM control system and a Hall position sensor, a zero-cross acquisition module, an insertion module, a 120-degree conduction calculation module and a 180-degree conduction calculation module. The defects of the prior art are overcome. For the limit of the square-wave operation of an existing brushless direct-current motor, a control system for reducing a torque ripple is designed under traditional square wave control and by means of a driving method in which a combination of a 120-degree conduction calculation module and a 180-degree conduction calculation module is used, such that multi-step commutation is simulated, thereby achieving the aim of reducing a square-wave-operating torque ripple of a brushless direct-current motor.

Description

A Control System for Reducing Torque Ripple of Brushless DC Motor in Square Wave Operation technical field

The invention belongs to the technical field of brushless direct current motors, and in particular relates to a control system for reducing square wave operation torque ripple of brushless direct current motors.

Background technique

Brushless DC motors are widely used in aerospace, CNC machine tools, medical equipment, household appliances and other fields because of their high efficiency, high power density, convenient control methods and long service life.

Traditional brushless DC motors often use six-step trapezoidal commutation with two-two conduction calculation modules, which is also the main reason for the large torque ripple of brushless DC motors in square wave operation. Therefore, it is necessary to develop a method that can reduce the torque ripple of the square wave operation of the brushless DC motor.

Contents of the invention

The purpose of the present invention is to provide a control system for reducing the torque ripple of brushless DC motor square wave operation, which overcomes the deficiencies in the prior art, and uses the combination of two-two conduction calculation modules and three-three conduction calculation modules The drive mode is used to solve the problem of relatively large torque ripple in the square wave operation of the brushless DC motor in the prior art. Aiming at the limitation of the square wave operation of the existing brushless DC motor, under the traditional square wave control, a set of reducing torque ripple is designed by adopting the driving method combining the two-two conduction calculation module and the three-three conduction calculation module. The control system simulates multi-step commutation, so as to achieve the purpose of reducing the torque ripple of brushless DC square wave operation.

In order to solve the above problems, the technical scheme adopted in the present invention is as follows:

A control system for reducing the torque ripple of brushless DC motor square wave operation, including a zero-crossing acquisition module, an insertion module, a two-two conduction calculation module, and a three-three conduction calculation module, wherein:

The zero-crossing acquisition module is connected with the Hall position sensor, and is used to acquire the zero-crossing point of the Hall sensor; the insertion module is connected with the zero-crossing acquisition module, and is used to determine the second guideline according to the zero-crossing point captured by the Hall sensor. The commutation sequence of the pass calculation module and the sequence of inserting the three-three conduction calculation module; the two-two conduction calculation module and the three-three conduction calculation module are respectively connected to the plug-in module for calculating the magnitude of the injected current , the two-two conduction calculation module and the three-three conduction calculation module are connected to the brushless DC motor through the BLDCM control system, and converted into PWM output to the BLDCM control system to control the operation of the brushless DC motor.

Optionally, the specific process of the zero-crossing acquisition module and the insertion module determining the commutation timing of the two-to-two conduction calculation module is as follows:

When the zero-crossing point of the rising edge of the hall sensor phase A is captured, the winding phase is A+, B-, the power switch is T1, T4, and the commutation sequence is 30°;

When the zero-crossing point of the falling edge of the hall sensor C phase is captured, the winding phase is A+, C-, the power switch is T1, T6, and the commutation sequence is 90°;

When the zero-crossing point of the rising edge of the hall sensor phase B is captured, the winding phase is B+, C-, the power switch is T3, T6, and the commutation sequence is 150°;

When the zero-crossing point of the falling edge of the hall sensor phase A is captured, the winding phase is B+, A-, the power switch is T3, T2, and the commutation sequence is 210°;

When the zero-crossing point of the rising edge of the Hall sensor phase C is captured, the winding phases are C+ and A-, the power switches are T5 and T2, and the commutation sequence is 270°;

When the zero-crossing point of the falling edge of the Hall sensor B phase is captured, the winding phases are C+ and B-, the power switches are T5 and T4, and the commutation sequence is 330°.

Optionally, the specific process of the zero-crossing acquisition module and the insertion module determining the timing of inserting the three-three conduction calculation module is as follows:

Determine the timing of inserting the three-three conduction calculation module: 0°, 60°, 120°, 180°, 240°, 300°;

At 0°, the energized phases of the winding are A+, C+, and B-, and the conduction power switches are T1, T5, and T4;

At 60°, the energized phases of the winding are A+, B-, C-, and the conduction power switches are T1, T4, T6;

At 120°, the winding energized phases are A+, B+, C-, and the conduction power switches are T1, T3, T6;

At 180°, the energized phases of the winding are B+, C-, A-, and the conduction power switches are T3, T6, T2;

At 240°, the winding energized phases are B+, C+, A-, and the conduction power switches are T3, T5, T2,

At 300°, the winding phases are C+, A-, B-, and the power switches are T5, T2, T4.

Optionally, the calculation principle of calculating the injection current by the two-two conduction calculation module and the three-three conduction calculation module is as follows:

同样假设三三导通计算模块时的流入中性点相电流为I，计算得出合成矢量模长为

为使二二导通计算模块与三三导通计算模块时的合成矢量模长相等，将二二导通计算模块时的流入中性点相电流变为

在调节电流相上施加调节后的PWM，调节后的PWM为原二二导通计算模块时的

倍。 Assuming that the positive-phase injection current is I when the two-two conduction calculation module is calculated, the synthetic vector modulus length is calculated as

It is also assumed that the phase current flowing into the neutral point when the three-three conduction calculation module is I, and the calculated composite vector modulus length is

In order to make the synthetic vector modulus lengths of the two-two conduction calculation module and the three-three conduction calculation module equal, the phase current flowing into the neutral point when the two-two conduction calculation module is changed to

The adjusted PWM is applied to the adjusted current phase, and the adjusted PWM is the original two-two conduction calculation module.

times.

Compared with the prior art, the present invention has the following beneficial effects:

1. Adopt the control system combining the two-two conduction calculation module and the three-three conduction calculation module, and combine the voltage vectors of the two conduction methods to obtain 12 sectors, which reduces the cost of the three-three conduction calculation module. The commutation torque ripple can effectively reduce the running noise of the brushless DC motor with the position sensor.

2. Adopting the control system combining the two-two conduction calculation module and the three-three conduction calculation module, combined with the voltage vector of the two conduction methods, the commutation is more accurate, and it is not easy to cause zero-crossing submersion and motor out of step. Therefore, it can be more adapted to the error during the actual commutation of the brushless DC motor, and further reduce the pulsation.

Description of drawings

Fig. 1 is the system diagram of the control system that reduces the square wave running torque ripple of the brushless DC motor;

Fig. 2 is a vector relationship diagram of A, B, and C phases under each commutation sequence of the control system for reducing the square wave operation torque ripple of the brushless DC motor;

Fig. 3 is the voltage diagram of the control system that reduces the square wave running torque ripple of the brushless DC motor;

Fig. 4 is a control flow chart for reducing square-wave running noise of a brushless DC motor.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Embodiment one

As shown in the figure, the present invention is shown in Figure 1. The present invention provides a control system for reducing the torque ripple of the square wave operation of the brushless DC motor, including: a zero-crossing point acquisition module, an insertion module, and a two-two conduction calculation module, three-three conduction calculation module, wherein: the zero-crossing acquisition module is connected with the Hall position sensor for obtaining the zero-crossing of the Hall sensor; the insertion module is connected with the zero-crossing acquisition module for according to The zero-crossing point captured by the Hall sensor determines the commutation timing of two-two conduction and the timing of inserting three-three conduction; the two-two conduction calculation module and the three-three conduction calculation module are respectively connected to the insertion module, Used to calculate the size of the injected current, the two-two conduction calculation module and the three-three conduction calculation module are connected to the brushless DC motor through the BLDCM control system, and converted into PWM output to the BLDCM control system to control the operation of the brushless DC motor.

Optionally, the specific process of determining the two-to-two conduction commutation sequence by the zero-crossing acquisition module and the insertion module is as follows:

When the zero-crossing point of the rising edge of the hall sensor phase A is captured, the winding phase is A+, B-, the power switch is T1, T4, and the commutation sequence is 30°;

When the zero-crossing point of the falling edge of the hall sensor C phase is captured, the winding phase is A+, C-, the power switch is T1, T6, and the commutation sequence is 90°;

When the zero-crossing point of the rising edge of the hall sensor phase B is captured, the winding phase is B+, C-, the power switch is T3, T6, and the commutation sequence is 150°;

When the zero-crossing point of the falling edge of the hall sensor phase A is captured, the winding phase is B+, A-, the power switch is T3, T2, and the commutation sequence is 210°;

When the zero-crossing point of the rising edge of the Hall sensor phase C is captured, the winding phases are C+ and A-, the power switches are T5 and T2, and the commutation sequence is 270°;

When the zero-crossing point of the falling edge of the Hall sensor B phase is captured, the winding phases are C+ and B-, the power switches are T5 and T4, and the commutation sequence is 330°.

Optionally, the specific process of the zero-crossing acquisition module and the insertion module determining the insertion three-three conduction sequence is as follows:

Determine the timing of inserting three-three conduction: 0°, 60°, 120°, 180°, 240°, 300°; at 0°, the winding phases are A+, C+, B-, and the power switches are T1, T5, T4; at 60°, the energized phase of the winding is A+, B-, C-, and the power switch is T1, T4, T6; at 120°, the energized phase of the winding is A+, B+, C-, and the power switch is turned on T1, T3, T6; at 180°, the energized phase of the winding is B+, C-, A-, and the conduction power switch is T3, T6, T2; at 240°, the energized phase of the winding is B+, C+, A-, the conduction When the power switches are T3, T5, T2, and 300°, the winding phases are C+, A-, B-, and the power switches are T5, T2, T4.

三三导通时，同样假设流入中性点相电流为I，那么流出中性点相电流均为

合成后的矢量与流入中性点相电流重合，其实际模长为

由于这两个矢量的模长不同，换相时会出现不必要的问题，所以需要控制三三导通时的输入电流，经计算，需要将三三导通时的流入中性点相电流变为

最终，电压空间矢量的运动轨迹如图3所示。 As shown in Figure 2, the present invention provides the vector relationship diagrams of A, B, and C phases under each commutation sequence after the new commutation point, and the corresponding commutation angles are 0°, 30°, 60°, 90°, and 120° respectively. °, 150°, 180°, 210°, 240°, 270°, 300°, 330°. When two and two are turned on, assuming that the phase current flowing into the neutral point is I, then the phase current flowing out of the neutral point is also I, and the corresponding synthetic vector current modulus length is

When three and three are turned on, it is also assumed that the phase current flowing into the neutral point is I, then the phase current flowing out of the neutral point is

The synthesized vector coincides with the phase current flowing into the neutral point, and its actual modulus length is

Because the modulus lengths of these two vectors are different, unnecessary problems will occur during commutation, so it is necessary to control the input current when the three-three is turned on. After calculation, it is necessary to change the phase current flowing into the neutral point when the three-three is turned on for

Finally, the trajectory of the voltage space vector is shown in Figure 3.

Embodiment two

A control method for reducing square-wave running noise of a brushless DC motor, comprising the steps of:

Step 1. When the brushless DC motor is running, obtain the zero-crossing point of the Hall sensor;

Step 2: According to the zero-crossing point captured by the Hall sensor, determine the commutation timing of the two-two conduction;

Step 3: According to the zero-crossing point captured by the Hall sensor, determine the timing of inserting the three-three conduction;

Step 4: Determine the size of the injection current for the third and third conduction according to the magnitude of the injection current for the second and second conduction in step 2;

Step 5: Correct the injection current under two-two conduction and three-three conduction; after correcting the injection current under two-two conduction and three-three conduction, judge again whether the resultant vector modulus length is equal under the two conduction modes, if If they are not equal, continue to correct until the resultant vector modulus length is equal in the two conduction modes, and the correction process ends.

It will be apparent to those skilled in the art that the invention is not limited to the details of the above-described exemplary embodiments, but that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Accordingly, the embodiments should be regarded in all points of view as exemplary and not restrictive, the scope of the invention being defined by the appended claims rather than the foregoing description, and it is therefore intended that the scope of the invention be defined by the appended claims rather than by the foregoing description. All changes within the meaning and range of equivalents of the elements are embraced in the present invention. Any reference sign in a claim should not be construed as limiting the claim concerned.

Claims (5)

A control system for reducing the torque ripple of brushless DC motor in square wave operation, including brushless DC motor, BLDCM control system and Hall position sensor, characterized in that it also includes a zero-crossing point acquisition module, a plug-in module, two and two conductors through calculation module and three-three conduction calculation module, the zero-crossing acquisition module is connected with the Hall position sensor for obtaining the zero-crossing point of the Hall sensor, and the insertion module is connected with the zero-crossing acquisition module for The zero-crossing point captured by the sensor determines the commutation timing of the 22 conduction calculation module and the timing sequence of inserting the 33 conduction calculation module, and the 22 conduction calculation module and the 33 conduction calculation module are respectively connected to the insertion module for Calculate the size of the injected current, the two-two conduction calculation module and the three-three conduction calculation module are connected to the brushless DC motor through the BLDCM control system, and converted into PWM output to the BLDCM control system to control the operation of the brushless DC motor. A control system for reducing the torque ripple of brushless DC motor square wave operation according to claim 1, characterized in that: the two-two conduction calculation module and the three-three conduction calculation module calculate the injection current The calculation principle is: assuming that the positive-phase injection current is I when the two-two conduction calculation module is calculated, the synthetic vector modulus length is calculated as

It is also assumed that the phase current flowing into the neutral point when the three-three conduction calculation module is I, and the calculated composite vector modulus length is

In order to make the synthetic vector modulus lengths of the two-two conduction calculation module and the three-three conduction calculation module equal, the phase current flowing into the neutral point when the three-three conduction calculation module is changed to

The adjusted PWM is applied to the adjusted current phase, and the adjusted PWM is the original three-three conduction calculation module.

times. According to claim 2, a control system for reducing the torque ripple of brushless DC motor square wave operation, characterized in that: said zero-crossing point acquisition module and insertion module determine the specific timing of commutation sequence of two-two conduction calculation module The process is as follows: When the zero-crossing point of the rising edge of the hall sensor phase A is captured, the winding phase is A+, B-, the power switch is T1, T4, and the commutation sequence is 30°; When the zero-crossing point of the falling edge of the hall sensor C phase is captured, the winding phase is A+, C-, the power switch is T1, T6, and the commutation sequence is 90°; When the zero-crossing point of the rising edge of the hall sensor phase B is captured, the winding phase is B+, C-, the power switch is T3, T6, and the commutation sequence is 150°; When the zero-crossing point of the falling edge of the hall sensor phase A is captured, the winding phase is B+, A-, the power switch is T3, T2, and the commutation sequence is 210°; When the zero-crossing point of the rising edge of the Hall sensor phase C is captured, the winding phases are C+ and A-, the power switches are T5 and T2, and the commutation sequence is 270°; When the zero-crossing point of the falling edge of the Hall sensor B phase is captured, the winding phases are C+ and B-, the power switches are T5 and T4, and the commutation sequence is 330°. According to claim 3, a control system for reducing the torque ripple of brushless DC motor square wave operation, characterized in that: the zero-crossing acquisition module and the insertion module determine the specific time sequence of the commutation sequence of the three-three conduction calculation module The process is as follows: determine the timing of inserting the three-three conduction calculation module as: 0°, 60°, 120°, 180°, 240°, 300°. A control system for reducing the torque ripple of brushless DC motor square wave operation according to claim 4, characterized in that: At 0°, the energized phases of the winding are A+, C+, and B-, and the conduction power switches are T1, T5, and T4; At 60°, the energized phases of the winding are A+, B-, C-, and the conduction power switches are T1, T4, T6; At 120°, the winding energized phases are A+, B+, C-, and the conduction power switches are T1, T3, T6; At 180°, the energized phases of the winding are B+, C-, A-, and the conduction power switches are T3, T6, T2; At 240°, the winding energized phases are B+, C+, A-, and the conduction power switches are T3, T5, T2, At 300°, the winding phases are C+, A-, B-, and the power switches are T5, T2, T4.

Images