阅读说明：本技术 无传感器控制中的自适应滤波控制方法及控制装置 (Adaptive filtering control method and control device in sensorless control ) 是由 王浩陈 魏海峰 张彬 李震 张懿 于 2019-10-31 设计创作，主要内容包括：本发明公开了一种无传感器控制中的自适应滤波控制方法,包括：获取无刷直流电机的相电感和相电阻；获取无刷直流电机运转过程中的工作电流；根据无刷直流电机的相电感和相电阻以及工作电流,计算消磁的作用时间；根据消磁的作用时间,计算自适应滤波过程中的滤波对比次数；根据滤波次数和滤波对比次数,执行自适应滤波,当滤波次数大于等于滤波对比次数时,执行换相；当滤波次数小于滤波对比次数时,不执行换相。本发明通过电路等效实现对消磁的作用时间的量化,科学地确定滤波次数,以现实自适应滤波。(The invention discloses a self-adaptive filtering control method in sensorless control, which comprises the following steps: acquiring phase inductance and phase resistance of the brushless direct current motor; acquiring working current of the brushless direct current motor in the running process; calculating the action time of demagnetization according to the phase inductance, the phase resistance and the working current of the brushless direct current motor; according to the action time of demagnetization, calculating the filtering contrast times in the self-adaptive filtering process; performing adaptive filtering according to the filtering times and the filtering comparison times, and performing phase change when the filtering times are more than or equal to the filtering comparison times; and when the filtering times are less than the filtering comparison times, not executing phase conversion. The invention realizes the quantification of the action time of degaussing through circuit equivalence, scientifically determines the filtering times, and realizes the self-adaptive filtering.)

1. An adaptive filtering control method in sensorless control, comprising:

step 1: acquiring phase inductance and phase resistance of the brushless direct current motor;

step 2: acquiring working current of the brushless direct current motor in the running process;

and step 3: calculating the action time of degaussing according to the phase inductance and the phase resistance of the brushless direct current motor obtained in the step 1 and the working current obtained in the step 2;

and 4, step 4: calculating the filtering contrast times in the self-adaptive filtering process according to the acting time of degaussing calculated in the step 3;

and 5: performing adaptive filtering, and performing phase conversion when the filtering times are more than or equal to the filtering comparison times; and when the filtering times are less than the filtering comparison times, not executing phase conversion.

2. The adaptive filtering control method in sensorless control according to claim 1, wherein the operating current in step 2 is a phase current peak value in a three-phase winding of the brushless dc motor.

3. The adaptive filtering control method in sensorless control according to claim 1, wherein the operating current in step 2 is a bus current.

4. The adaptive filtering control method in sensorless control according to claim 2, wherein the action time of degaussing is calculated in step 3 by the following formula:

wherein, t is the acting time of degaussing; "τ" is a time constant; l is the phase inductance of the brushless DC motor; "R" is the phase resistance of the brushless DC motor; "I _e"is a preset current threshold; "i ₀"is the peak value of phase current in three-phase winding of brushless DC motor;

5. The adaptive filtering control method in sensorless control according to claim 3, wherein the action time of degaussing is calculated in step 3 by the following formula:

wherein, t is the acting time of degaussing; "τ" is a time constant; l is the phase inductance of the brushless DC motor; "R" is the phase resistance of the brushless DC motor; "I _eValve for preset currentA value; "I ₀"is the bus current.

6. The adaptive filtering control method in sensorless control according to claim 4 or 5, wherein the preset current threshold is 0.05.

7. The adaptive filtering control method in sensorless control according to claim 1, wherein the adaptive filtering performed in step 5 is adaptive filtering for each opposite potential signal of three-phase windings of the brushless dc motor, and the adaptive filtering for each phase comprises the following specific steps:

step 51: acquiring the level of a back electromotive force signal of a phase winding of the brushless direct current motor at preset sampling time intervals, and executing adaptive filtering when the level jumps;

step 52: continuously acquiring the level of a back electromotive force signal of a phase winding of the brushless direct current motor at preset sampling time intervals, finishing adaptive filtering when the level jumps, resetting the filtering times, and returning to the step 51; when the level is not jumped, judging whether the filtering times are more than or equal to the filtering comparison times, when the filtering times are more than or equal to the filtering comparison times, stopping the self-adaptive filtering, resetting the filtering times, executing phase change, and returning to the step 51; and when the filtering times are less than the filtering comparison times, adding one to the filtering times, and returning to the step 52.

8. The adaptive filtering control method in sensorless control according to claim 7, wherein the preset sampling time in step 51 and step 52 is

9. The adaptive filtering control method in sensorless control according to claim 1, wherein the calculation formula for calculating the number of filter contrasts in the adaptive filtering process according to the action time of degaussing calculated in step 3 in step 4 is:

wherein, N is the filtering comparison times; "t" is the acting time of demagnetization; "T ₀"is a preset sampling time; "[]"represents a rounding operation.

10. An adaptive filter control apparatus in a sensorless control, comprising: partial pressure filtering module, comparator module, current acquisition module, controller, driver module, dc-to-ac converter module, brushless DC motor three-phase winding, wherein:

the voltage division filtering module is connected with the three-phase winding of the brushless direct current motor and is used for dividing and filtering the acquired terminal voltage of the three-phase winding of the brushless direct current motor and outputting the voltage; the comparator module is connected with the voltage division filtering module and is used for converting the output signal of the voltage division filtering module into a square wave signal to be output; the current acquisition module is connected with the three-phase winding of the brushless direct current motor and is used for acquiring the current of the three-phase winding of the brushless direct current motor; the controller is respectively connected with the current acquisition module, the comparator module and the driver module, and is used for analyzing and processing the output signal of the current acquisition module and the output signal of the comparator module and outputting a driving signal to the driver module; the driver module is connected with the inverter module and is used for driving the power device in the inverter module to be switched on and off; and the inverter module is connected with the three-phase winding of the brushless direct current motor and is used for realizing the phase change operation of the brushless direct current motor.

Technical Field

The invention relates to the field of brushless direct current motor control. And more particularly, to an adaptive filtering control method and apparatus for a demagnetization phenomenon in a sensorless control.

Background

The brushless DC motor belongs to a kind of permanent magnet synchronous motor, and has the advantages of high efficiency, fast response, low noise, etc.

In the square wave sensorless control, a non-conducting phase has a follow current problem in a phase change process, so that a back electromotive force waveform can generate a demagnetization phenomenon, and the demagnetization phenomenon is aggravated along with the increase of load current. At present, the common practice is to adopt an empirical filtering method, and the size of the working current and the phase inductance characteristic of the brushless direct current motor are not considered, so that the method has poor adaptability.

The invention provides a method for easily realizing self-adaptive filtering according to the magnitude of working current, the phase resistance of a brushless direct current motor and the phase inductance of the brushless direct current motor.

Disclosure of Invention

The invention provides a self-adaptive filtering control method and a self-adaptive filtering control device in sensorless control, which aim to solve the problem of poor adaptability of a filtering algorithm aiming at a degaussing phenomenon in the traditional sensorless control.

The invention provides a self-adaptive filtering control method in sensorless control, which comprises the following steps:

step 1: acquiring phase inductance and phase resistance of the brushless direct current motor;

step 2: acquiring working current of the brushless direct current motor in the running process;

and step 3: calculating the action time of degaussing according to the phase inductance and the phase resistance of the brushless direct current motor obtained in the step 1 and the working current obtained in the step 2;

and 4, step 4: calculating the filtering contrast times in the self-adaptive filtering process according to the acting time of degaussing calculated in the step 3;

and 5: performing adaptive filtering, and performing phase conversion when the filtering times are more than or equal to the filtering comparison times; and when the filtering times are less than the filtering comparison times, not executing phase conversion.

Optionally, the working current in step 2 is a phase current peak value in a three-phase winding of the brushless dc motor.

Optionally, the operating current in step 2 is a bus current.

Optionally, the acting time of degaussing is calculated in step 3, and the specific formula is as follows:

wherein, t is the acting time of degaussing; "τ" is a time constant; l is the phase inductance of the brushless DC motor; "R" is the phase resistance of the brushless DC motor; "I _e"is a preset current threshold; "i ₀"is the peak value of phase current in three-phase winding of brushless DC motor; the effective value of the phase current in the three-phase winding of the brushless direct current motor is obtained.

Optionally, the acting time of degaussing is calculated in step 3, and the specific formula is as follows:

wherein, t is the acting time of degaussing; "τ" is a time constant; l is the phase inductance of the brushless DC motor; "R" is the phase resistance of the brushless DC motor; "I _e"is a preset current threshold; "I ₀"is the bus current.

Optionally, the preset current threshold is 0.05.

Optionally, the step 5 of performing adaptive filtering is to perform adaptive filtering on each opposite potential signal of the three-phase winding of the brushless dc motor, and the specific steps of each phase of adaptive filtering are as follows:

step 51: acquiring the level of a back electromotive force signal of a phase winding of the brushless direct current motor at preset sampling time intervals, and executing adaptive filtering when the level jumps;

step 52: continuously acquiring the level of a back electromotive force signal of a phase winding of the brushless direct current motor at preset sampling time intervals, finishing adaptive filtering when the level jumps, resetting the filtering times, and returning to the step 51; when the level is not jumped, judging whether the filtering times are more than or equal to the filtering comparison times, when the filtering times are more than or equal to the filtering comparison times, stopping the self-adaptive filtering, resetting the filtering times, executing phase change, and returning to the step 51; and when the filtering times are less than the filtering comparison times, adding one to the filtering times, and returning to the step 52.

Optionally, the preset sampling time in step 51 and step 52 is

Wherein "f _PWM"is the PWM frequency of the brushless DC motor.

Optionally, in step 4, according to the acting time of degaussing calculated in step 3, a calculation formula for calculating the filtering contrast number in the adaptive filtering process is as follows:

wherein, N is the filtering comparison times; "t" is the acting time of demagnetization; "T ₀"is a preset sampling time; "[]"represents a rounding operation.

The invention provides a self-adaptive filtering control device in sensorless control, which comprises: partial pressure filtering module, comparator module, current acquisition module, controller, driver module, dc-to-ac converter module, brushless DC motor three-phase winding, wherein:

the voltage division filtering module is connected with the three-phase winding of the brushless direct current motor and is used for dividing and filtering the acquired terminal voltage of the three-phase winding of the brushless direct current motor and outputting the voltage; the comparator module is connected with the voltage division filtering module and is used for converting the output signal of the voltage division filtering module into a square wave signal to be output; the current acquisition module is connected with the three-phase winding of the brushless direct current motor and is used for acquiring the current of the three-phase winding of the brushless direct current motor; the controller is respectively connected with the current acquisition module, the comparator module and the driver module, and is used for analyzing and processing the output signal of the current acquisition module and the output signal of the comparator module and outputting a driving signal to the driver module; the driver module is connected with the inverter module and is used for driving the power device in the inverter module to be switched on and off; and the inverter module is connected with the three-phase winding of the brushless direct current motor and is used for realizing the phase change operation of the brushless direct current motor.

The invention at least comprises the following beneficial effects:

1. the demagnetization action time is calculated through the phase resistance, the phase inductance and the working current of the brushless direct current motor, the circuit is equivalent to an RL typical charging and discharging circuit through the calculation method, the method is scientific and easy to realize, and accurate calculation basis is provided for selection of filtering times in filtering.

2. The filtering comparison times are calculated according to the action time of demagnetization and the preset sampling time/the PWM frequency of the brushless direct current motor by a filtering method for repeatedly checking the level state after jumping, the calculating method is strong in self-adaptive capacity and suitable for the brushless direct current motors with different parameters.

Drawings

The features and advantages of the present invention will be more clearly understood by reference to the accompanying drawings, which are illustrative and not to be construed as limiting the invention in any way, and in which:

FIG. 1 is a flow chart of a method for adaptive filtering control in sensorless control according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of an adaptive filtering control apparatus in sensorless control according to an embodiment of the present invention;

fig. 3 is a diagram showing the signals of the phase a of the three-phase winding of the brushless dc motor according to the embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1, the present invention provides an adaptive filtering control method in sensorless control, including:

step S1: acquiring phase inductance and phase resistance of the brushless direct current motor;

step S2: acquiring working current of the brushless direct current motor in the running process;

step S3: calculating the action time of degaussing according to the phase inductance and the phase resistance of the brushless direct current motor obtained in the step S1 and the working current obtained in the step 2;

step S4: calculating the filtering contrast times in the self-adaptive filtering process according to the action time of degaussing calculated in the step S3;

step S5: acquiring the level of a back electromotive force signal of a three-phase winding of the brushless direct current motor at preset sampling time intervals, and executing adaptive filtering when the level jumps;

step S6: continuously acquiring the level of a back electromotive force signal of a three-phase winding of the brushless direct current motor at preset sampling time intervals, and judging whether the level jumps or not: when the level jumps, completing the adaptive filtering, resetting the filtering times, and returning to the step S5; when the level is not jumped, judging whether the filtering times are more than or equal to the filtering comparison times: when the filtering times is greater than or equal to the filtering comparison times, stopping the adaptive filtering, resetting the filtering times, executing phase change, and returning to the step S5; when the filtering times is smaller than the filtering comparison times, the filtering times is increased by one, and the process returns to the step S6.

When the working current in step S2 is the peak value of the phase current in the three-phase winding of the brushless dc motor, the specific formula for calculating the acting time of demagnetization is as follows:

wherein, t is the acting time of degaussing; "τ" is a time constant; "L" is the phase inductance of the brushless dc motor, unit: h; "R" is the phase resistance of the brushless dc motor, unit: omega; "I _e"is a preset current threshold; "i ₀"is the peak value of phase current in three-phase winding of brushless DC motor, unit: a; the effective value of phase current in a three-phase winding of the brushless direct current motor is represented by the following unit: A.

when the working current in step S2 is the bus current, the action time of demagnetization is calculated, and the specific formula is as follows:

wherein, t is the acting time of degaussing; "τ" is a time constant; "L" is the phase inductance of the brushless dc motor, unit: h; "R" is the phase resistance of the brushless dc motor, unit: omega; "I _e"is a preset current threshold, unit: a; "I ₀"is bus current, unit: A.

the formula (1) or (2) is composed of

The formula is an RL circuit discharge formula, and the current I can be calculated ₀Attenuation to I _eThe elapsed time can be equivalent to an RL circuit when the brushless DC motor runs, the demagnetization process of the floating phase circuit is equivalent to the discharge process of the RL circuit, and the demagnetization acting time can be obtained through the formula.

Optionally, the preset current threshold is 0.05, unit: a; used as a current reference for the end of the degaussing event since the degaussing can be assumed to have ended by the time the current drops to 0.05.

Alternatively, the preset sampling time is equal to the preset sampling time in steps S5 and S6 Wherein "f _PWM"is the PWM frequency of the brushless DC motor. This setting is used because the triggering of sampling is usually done in the timer of the PWM.

Optionally, the calculation method of the filtering contrast times according to the action time of degaussing and the preset sampling time in step S4 includes:

wherein, N is the filtering comparison times; "t" is the action time of demagnetization, unit: s; "T ₀"is a preset sampling time, unit: s; "[]"represents a rounding operation.

The formula quantizes the filter comparison times according to the preset sampling time, and the +1 ensures that the filter times can cover the action time of demagnetization so as to avoid the influence of demagnetization on phase commutation.

As shown in fig. 2, the present invention provides an adaptive filtering control apparatus in sensorless control, including: partial pressure filtering module, comparator module, current acquisition module, controller, driver module, dc-to-ac converter module, brushless DC motor three-phase winding, wherein:

the voltage division filtering module is connected with the three-phase winding of the brushless direct current motor and is used for outputting the collected terminal voltage of the three-phase winding of the brushless direct current motor after voltage division filtering; the comparator module is connected with the voltage division filtering module and is used for converting the output signal of the voltage division filtering module into a square wave signal to be output; the current acquisition module is connected with the three-phase winding of the brushless direct current motor and is used for acquiring the current of the three-phase winding of the brushless direct current motor; the controller is respectively connected with the current acquisition module, the comparator module and the driver module, and is used for analyzing and processing the output signal of the current acquisition module and the output signal of the comparator module and outputting a driving signal to the driver module; the driver module is connected with the inverter module and is used for driving the power device in the inverter module to be switched on and off; and the inverter module is connected with the three-phase winding of the brushless direct current motor and is used for realizing the phase change operation of the brushless direct current motor. The testing method comprises the steps that X1 is a testing point of back electromotive force of a brushless direct current motor three-phase winding A phase, Y1 is a testing point of back electromotive force signals of the brushless direct current motor three-phase winding A phase converted through a voltage division filtering module, and Z1 is a testing point of back electromotive force signals of the brushless direct current motor three-phase winding A phase converted through a comparator module.

Fig. 3 is a diagram showing an example of the signal of the phase a of the three-phase winding of the brushless dc motor, wherein fig. 3(a) is the output waveform of the test point X1 in fig. 2, fig. 3(b) is the output waveform of the test point Y1 in fig. 2, and fig. 3(c) is the output waveform of the test point Z1 in fig. 2. In this embodiment, the phase inductance of the brushless dc motor is 80mH, the phase resistance is 0.8 Ω, the PWM frequency is 16KHz, and the preset sampling time is 62.5 us; when the bus current is 1A, the oscilloscope test chart shown in the figure 3 is obtained. The demagnetization acting time is calculated according to the formula (2) and is as follows:

and (3) calculating the degaussing action time as the filtering comparison times according to a formula (3):

when the controller detects that the square wave signal converted by the counter potential signal comparator module of the A phase of the three-phase winding of the brushless direct current motor generates level jump at the C1 point, filtering is started, but the level jump is generated again after repeated detection that the filtering comparison times are 5 times, namely jump is generated at the C2 point; and at this time, the back electromotive force signals of the A phase of the three-phase winding of the brushless direct current motor are continuously detected, and the phase change is not executed.

When the bus current is 2A, calculating according to the formula (2) to obtain the demagnetization action time as follows:

and (3) calculating the degaussing action time as the filtering comparison times according to a formula (3):

when the peak value of phase current in a three-phase winding of the brushless direct current motor is 3.2A, the demagnetization action time is calculated according to the formula (1) and is as follows:

and (3) calculating the degaussing action time as the filtering comparison times according to a formula (3):

it is obvious that those skilled in the art can obtain various effects not directly mentioned according to the respective embodiments without trouble from various structures according to the embodiments of the present invention. While the invention/embodiments of the invention have been disclosed above, it is not limited to the applications listed in the description and the embodiments. It can be applied to all kinds of fields suitable for the present invention. Additional modifications will readily occur to those skilled in the art. It is therefore intended that the invention not be limited to the exact details and illustrations described and illustrated herein, but fall within the scope of the appended claims and equivalents thereof.