CN107437910B - Dust collector, motor and constant power control method and device of motor - Google Patents
Dust collector, motor and constant power control method and device of motor Download PDFInfo
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- CN107437910B CN107437910B CN201710807809.9A CN201710807809A CN107437910B CN 107437910 B CN107437910 B CN 107437910B CN 201710807809 A CN201710807809 A CN 201710807809A CN 107437910 B CN107437910 B CN 107437910B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P7/00—Arrangements for regulating or controlling the speed or torque of electric DC motors
- H02P7/06—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current
- H02P7/18—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power
- H02P7/24—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices
- H02P7/28—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices using semiconductor devices
- H02P7/285—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices using semiconductor devices controlling armature supply only
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P7/00—Arrangements for regulating or controlling the speed or torque of electric DC motors
- H02P7/06—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current
- H02P7/18—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power
- H02P7/24—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices
- H02P7/28—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices using semiconductor devices
- H02P7/285—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices using semiconductor devices controlling armature supply only
- H02P7/29—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices using semiconductor devices controlling armature supply only using pulse modulation
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- Control Of Motors That Do Not Use Commutators (AREA)
Abstract
The invention discloses a dust collector, a motor and a constant power control method and device thereof, wherein the constant power control method comprises the following steps: acquiring direct-current bus voltage and direct-current bus current of a motor; obtaining a direct current bus current given value of the motor through table lookup according to the direct current bus voltage and the power given value of the motor; acquiring a current difference value between a given value of the direct current bus current and the direct current bus current; and carrying out PI regulation on the current difference value to obtain a duty ratio signal for controlling the motor, and carrying out constant power control on the motor according to the duty ratio signal. The method realizes the constant power control of the motor by carrying out PI control on the direct current bus current, does not increase the hardware cost, can realize the effects of large-scale power regulation and continuous control without using a position sensor, and can effectively solve the problem of poor control effect caused by the influence of environmental factors in the production process.
Description
Technical Field
The invention relates to the technical field of motor control, in particular to a constant power control method of a motor, a constant power control device of the motor, the motor with the control device and a dust collector.
Background
At present, a Brushless Direct Current Motor (BLDC) with high speed and small size is increasingly used, especially in the field of small electric tools such as a hand-held vacuum cleaner. When a small electric tool is powered by a battery, the voltage of the battery gradually decreases along with the change of the use time, and in order to enable a device to output constant power, a constant power control strategy needs to be introduced in the process of the voltage decrease of the battery.
In the related art, the constant power control of the motor is realized by changing the advance angle and the follow current angle by looking up a table. Specifically, as shown in fig. 1 and 2, the input voltage of the motor, i.e., the battery voltage, is detected in real time, then the advance angle and the freewheel angle required for controlling the motor are obtained by looking up a table according to the input voltage, and when the position of the hall sensor is updated, the control voltage is determined to be output and turned off according to the position signal of the current time or the previous time, so as to realize the constant power control of the motor.
However, when the above control method is adopted, the following disadvantages exist:
(1) the change of power is related to the current speed and the load state, the pulse width output by a data table is a single discrete action point, the pulse width is not suitable for continuous and violent changes of load and speed, and step change is easy to occur, so that the output power is pulsed;
(2) the data table is obtained by testing the motor, and in the production process, the motor is easily influenced by various environmental factors to cause inconsistent parameters, so that functional deviation is caused, and the power control effect in actual use is greatly reduced;
(3) the advance angle control has a certain advance limit, and in order to break through the limit, only the position signal of an external Hall sensor can be introduced for solving the problem, so that the power controllable range of the brushless direct current motor without the position sensor is limited.
Disclosure of Invention
The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. Therefore, a first objective of the present invention is to provide a constant power control method for a motor, which performs PI control on a dc bus current to realize constant power control of the motor, so as to achieve the effects of large-scale power adjustment and continuous control without increasing hardware cost, and without using a position sensor, and effectively improve the problem of poor control effect caused by environmental factors during the production process.
A second object of the invention is to propose a non-transitory computer-readable storage medium. A third object of the present invention is to provide a constant power control apparatus for an electric motor. A fourth object of the invention is to propose an electric machine. A fifth object of the present invention is to provide a vacuum cleaner.
In order to achieve the above object, an embodiment of a first aspect of the present invention provides a constant power control method for an electric motor, including the following steps: s1, acquiring direct current bus voltage and direct current bus current of the motor; s2, obtaining the direct current bus current given value of the motor through table lookup according to the direct current bus voltage and the power given value of the motor; s3, acquiring a current difference value between the given value of the direct current bus current and the direct current bus current; and S4, performing PI regulation on the current difference value to obtain a duty ratio signal for controlling the motor, and performing constant power control on the motor according to the duty ratio signal.
According to the constant power control method of the motor, the direct current bus voltage and the direct current bus current of the motor are obtained, then the direct current bus current given value of the motor is obtained through table lookup according to the direct current bus voltage and the power given value of the motor, the current difference value between the direct current bus current given value and the direct current bus current is obtained, PI adjustment is conducted on the current difference value to obtain a duty ratio signal used for controlling the motor, and constant power control is conducted on the motor according to the duty ratio signal. The method realizes the constant power control of the motor by carrying out PI control on the direct current bus current, does not increase the hardware cost, can realize the effects of large-scale power regulation and continuous control without using a position sensor, and can effectively solve the problem of poor control effect caused by the influence of environmental factors in the production process.
According to one embodiment of the invention, when the given value of the direct current bus current of the motor is obtained through table lookup according to the direct current bus voltage and the given value of the power of the motor, low-pass filtering processing is further performed on the direct current bus voltage.
According to an embodiment of the present invention, the method for controlling constant power of an electric motor further includes: acquiring the end voltage of the motor; acquiring a back electromotive force zero-crossing signal of the motor according to the end voltage of the motor; and controlling the motor to commutate according to the back electromotive force zero-crossing signal of the motor, and acquiring a duty ratio signal for controlling the motor after the commutation is finished.
According to one embodiment of the invention, the direct current bus current of the motor is acquired through a direct current bus sampling resistor.
To achieve the above object, a second aspect of the present invention provides a non-transitory computer-readable storage medium, on which a computer program is stored, the computer program, when executed by a processor, implementing the above method.
By executing the constant power control method, the non-transitory computer-readable storage medium of the embodiment of the invention can realize the constant power control of the motor by performing the PI control on the direct current bus current, not only does not increase the hardware cost, but also can realize the effects of large-scale power regulation and continuous control without using a position sensor, and can effectively solve the problem of poor control effect caused by the influence of environmental factors in the production process.
In order to achieve the above object, a constant power control apparatus for an electric motor according to an embodiment of a third aspect of the present invention includes: the bus voltage acquisition module is used for acquiring the direct current bus voltage of the motor; the bus current acquisition module is used for acquiring the direct current bus current of the motor; the current given module is used for obtaining a direct current bus current given value of the motor through table lookup according to the direct current bus voltage and the power given value of the motor; the deviation obtaining module is used for obtaining a current difference value between the given value of the direct current bus current and the direct current bus current; the PI adjusting module is used for carrying out PI adjustment on the current difference value to obtain a duty ratio signal for controlling the motor; and the control module is used for carrying out constant power control on the motor according to the duty ratio signal.
According to the constant power control device of the motor, the bus voltage obtaining module is used for obtaining the direct current bus voltage of the motor, the bus current obtaining module is used for obtaining the direct current bus current of the motor, and the current setting module is used for obtaining the direct current bus current set value of the motor through table lookup according to the direct current bus voltage and the power set value of the motor. Then, a current difference value between the given value of the direct current bus current and the direct current bus current is obtained through a deviation obtaining module, PI regulation is carried out on the current difference value through a PI regulation module to obtain a duty ratio signal used for controlling the motor, and constant power control is carried out on the motor through a control module according to the duty ratio signal. The device is through carrying out PI control to direct current bus current in order to realize the constant power control to the motor, not only can not increase the hardware cost, need not to use position sensor moreover and can realize the effect of power regulation and continuous control on a large scale, can effectively improve the poor problem of control effect that leads to because of environmental factor influences in the production process simultaneously.
According to an embodiment of the present invention, the constant power control apparatus for an electric motor further includes: and the filtering processing module is used for carrying out low-pass filtering processing on the direct-current bus voltage.
According to an embodiment of the present invention, the constant power control apparatus for an electric motor further includes: the terminal voltage acquisition module is used for acquiring the terminal voltage of the motor; the back electromotive force zero-crossing acquisition module is used for acquiring a back electromotive force zero-crossing signal of the motor according to the end voltage of the motor; the control module is further configured to control the motor to perform commutation according to the back electromotive force zero-crossing signal, and obtain a duty ratio signal for controlling the motor after the commutation is completed.
According to one embodiment of the invention, the bus current obtaining module obtains the dc bus current of the motor through a dc bus sampling resistor.
In order to achieve the above object, a fourth aspect of the present invention provides an electric machine, which includes the above constant power control apparatus.
According to the motor provided by the embodiment of the invention, through the constant power control device, the constant power control of the motor can be realized by carrying out PI control on the direct current bus current, so that the hardware cost is not increased, the effects of large-scale power regulation and continuous control can be realized without using a position sensor, and the problem of poor control effect caused by environmental factors in the production process can be effectively solved.
According to one embodiment of the invention, the motor is a three-phase brushless dc motor.
In order to achieve the above object, a fifth embodiment of the present invention provides a vacuum cleaner, which includes the above motor.
According to the dust collector provided by the embodiment of the invention, the motor can realize constant-power operation.
Drawings
Fig. 1 is a schematic diagram of a motor constant power control realized by changing an advance angle and a freewheel angle in the related art;
fig. 2 is a table showing a relationship among a battery voltage, an advance angle, a freewheel angle, and an output power in the related art;
FIG. 3 is a block diagram of a control system for a three-phase brushless DC motor according to one embodiment of the present invention;
FIG. 4 is a flow chart of a method of constant power control of an electric machine according to an embodiment of the present invention;
FIG. 5 is a block schematic diagram of a constant power control arrangement for an electric machine according to one embodiment of the present invention;
FIG. 6 is a schematic diagram of a back EMF zero crossing process in accordance with one embodiment of the present invention;
FIG. 7 is a schematic diagram of a back EMF zero crossing process according to another embodiment of the present invention;
FIG. 8 is a flow chart of a method of constant power control of an electric machine according to one embodiment of the present invention; and
fig. 9 is a block schematic diagram of a constant power control apparatus of a motor according to another embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
The following describes a constant power control method of a motor, a non-transitory computer readable storage medium, a constant power control apparatus of a motor, a motor having the control apparatus, and a vacuum cleaner according to an embodiment of the present invention with reference to the drawings.
In an embodiment of the present invention, the motor may be a three-phase brushless dc motor, a rotor of the three-phase brushless dc motor may be formed of a permanent magnet having a structure of at least one pair of magnetic poles, and a stator may be formed of a three-phase winding.
Fig. 3 is a block diagram of a control system for a three-phase brushless dc motor according to an embodiment of the present invention. As shown in fig. 3, a control system of a three-phase brushless dc motor may include a dc power supply 101 (e.g., a battery), a dc bus support capacitor 102 (e.g., a large electrolytic capacitor), a three-phase bridge 103, a dc bus voltage sampling circuit 104, a dc bus current sampling circuit 105, a motor terminal voltage sampling circuit 106, and an MCU.
The direct current bus current sampling circuit is used for sampling to obtain a direct current bus current idcAnd applying the DC bus current idcAnd transmitting the data to the MCU for operation processing. Wherein, the DC bus current idcEqual to the three-phase output current instantaneous value i of the motoru、ivAnd iwThe square sum of the root, i.e.
Or, the DC bus current idcEqual to the three-phase output current instantaneous value i of the motoru、ivAnd iwThe square and root of instantaneous value of dq-axis current, rotationally transformed into a two-phase rotating coordinate system, i.e. the square and root
Wherein idFor d-axis current transients (also known as field currents), iqIs the q-axis current transient (also known as the torque current).
When the three-phase brushless direct current motor works at a rated rotating speed, equivalent exciting current i flows in a stator winding of the motordSatisfies the following formula (1):
id≈0 (1)
at this time, the DC bus current idcSatisfies the following formula (2):
idc≈iq(2)
the input power of the motor is the output power of the dc power supplyWhich is equal to the power of the dc bus support capacitor. The direct-current bus supporting capacitor plays a role in supporting bus voltage by flat waves when the three-phase bridge is conducted to work, and the direct-current bus voltage V can be sampled by the direct-current bus voltage sampling circuitdcWhen the power is transmitted to the MCU, the input power, namely the output power of the direct current power supply, satisfies the following formula (3):
Pin＝Vdc*idc(3)
as can be seen from the above equation (3), the output power P of the DC power supplyinAnd DC bus voltage VdcAnd a DC bus current idcRelated, and DC bus current idcWith q-axis current transient iqSubstantially the same, so that in an embodiment of the invention, the current i can pass through the direct busdcEquivalent q-axis current transient iqThe method of (3) to achieve constant power control of the motor.
Fig. 4 is a flowchart of a constant power control method of a motor according to an embodiment of the present invention. As shown in fig. 4, the method for controlling constant power of a motor according to an embodiment of the present invention includes the following steps:
and S1, acquiring the direct current bus voltage and the direct current bus current of the motor.
According to an embodiment of the present invention, as shown in fig. 3, the dc bus voltage V may be obtained by sampling with a dc bus voltage sampling circuit (e.g., a resistance voltage divider circuit)dc(ii) a Sampling by a DC bus current sampling circuit (such as a DC bus sampling resistor) to obtain a voltage signal, and converting the voltage signal into a current signal to obtain a DC bus current idc。
And S2, obtaining the direct current bus current given value of the motor through table lookup according to the direct current bus voltage and the power given value of the motor.
Specifically, since the voltage of the dc power supply (e.g., a battery) gradually decreases with time, the dc bus voltage V is set to achieve constant power control of the motordcThe feedback quantity is used for participating in the control of the motor, and the direct-current bus voltage V can be detected in real time through the sampling circuitdcThen according to the real-time detected DC bus voltage VdcAnd the given power value (actually required power) P of the current motor*Obtaining the direct current bus current given value i of the motor by looking up the tabledc *Then setting a value i according to the DC bus currentdc *And controlling the motor. In particular, table 1 gives the dc bus voltage VdcAnd given power value P of motor*Given value i of direct current bus currentdc *The relationship between them.
TABLE 1
Wherein, when the power is given value P*At 350W, if the DC bus voltage VdcAt 25.2V, the direct current bus current given value idc *Is 13.89A; if the DC bus voltage VdcAt 25.1V, the direct current bus current given value idc *Is 13.94A; if the DC bus voltage VdcAt 25.0V, the direct current bus current given value idc *Is 14.00A; … are provided.
In practical applications, the above table 1 can be programmed to generate the actual dc bus voltage VdcThe related two-dimensional array can be used for quickly finding out the direct current bus voltage V fed back currentlydcGiven power value P*And the corresponding current instruction is used for carrying out current control on the motor according to the current instruction. Because the current instruction is obtained by using a table look-up mode, division operation for generating the current instruction is avoided, and the calculation time is saved.
Further, according to an embodiment of the present invention, when the dc bus current set value of the motor is obtained by looking up the table according to the dc bus voltage and the power set value of the motor, the dc bus voltage is also subjected to the low pass filtering process.
That is, the DC bus voltage V is obtained after samplingdcThen, the DC bus voltage V can be first aligneddcA low pass filtering process is performed as shown in fig. 5, and then according to the low pass filteringProcessed DC bus voltage Vdc *(can be called DC bus voltage given value V)dc *) Given power value P*Obtaining the given value i of the direct current bus current by looking up the tabledc *Therefore, the power control can be more stable, and the power pulsation is reduced.
And S3, acquiring a current difference value between the given value of the direct current bus current and the direct current bus current.
And S4, performing PI regulation on the current difference value to obtain a duty ratio signal for controlling the motor, and performing constant power control on the motor according to the duty ratio signal.
Specifically, as shown in fig. 5, the direct current bus current is given by a given value idc *With a DC bus current idcCurrent difference value △ i betweendc＝idc *-idcThe output signal is used as the error amount of negative feedback adjustment and is sent to a PI adjuster, the PI adjuster adjusts and outputs a signal for controlling the pulse width, namely a Duty ratio signal Duty, then a PWM unit outputs a driving signal to a three-phase bridge according to the Duty ratio signal Duty so as to conduct on/off control on a switching tube of the three-phase bridge, and finally required voltage is obtained and is supplied to a three-phase brushless direct current motor, so that the power constant adjustment function of stable control by means of direct current bus current is realized.
Because the PI control is carried out by the mode of the detected direct current bus current, the effect of continuous control can be achieved, and the problem of output power pulsation caused by table look-up value fluctuation caused by preset advance angles and follow-up flow angle tables in the related technology is avoided; meanwhile, due to the introduction of PI control, the system can have a wider stable band characteristic in a closed-loop negative feedback mode, so that the influence of the motor parameter change caused in the production process on the system is very low, the factory debugging process is simplified, and the production efficiency is improved. In addition, the detection of the direct current bus current is originally used for overcurrent protection of the motor, the detection method is expanded into power control, the hardware cost is not additionally increased, and the large-scale constant power adjustment can be realized without using a position sensor. In addition, the control process is simple, so that a stable control effect can be realized by using a low-cost MCU, and the production cost is reduced.
Further, according to an embodiment of the present invention, the method for controlling constant power of a motor further includes: acquiring the end voltage of the motor; acquiring a back electromotive force zero-crossing signal of the motor according to the end voltage of the motor; and controlling the motor to commutate according to the counter electromotive force zero-crossing signal of the motor, and acquiring a duty ratio signal for controlling the motor after the commutation is finished.
Specifically, the end voltage U of the motor can be obtained by a terminal voltage sampling circuit (such as a voltage transformer)u、Uv、UwThen according to the end voltage U of the motoru、Uv、UwAcquiring a back electromotive force zero-crossing signal of the motor (when the end voltage changes to 1/2V)dcCan be used instead of the back emf zero crossing), which can be read by means of an external interrupt, the waveform of which is shown in fig. 6; the inquiry can also be performed by means of software timer interrupt, and the waveform of the inquiry is shown in fig. 7. It should be noted that, both the zero-crossing reading processes in the two modes have a certain window time, and under normal conditions, in a non-detection window period, software masks the zero-crossing signal of the back electromotive force, and in a detection window period, receives the zero-crossing signal, and after receiving an effective zero-crossing signal, starts to perform the zero-crossing process and the corresponding PWM output.
Specifically, when the processed back electromotive force zero-crossing signal is changed from negative to positive, the zero-crossing processing is triggered by external interruption or a turnover signal inquired by a software timer, in the process of the zero-crossing processing, the motor is controlled to carry out commutation and PWM output, and after the commutation is finished, a duty ratio signal required by the next control period is obtained according to the detected direct current bus voltage and the direct current bus current. After the commutation is finished, the time is 60 degrees from the next commutation, so that enough time is provided for finishing the control operation of table lookup and current loop.
Further, fig. 8 is a flowchart of a constant power control method of the motor according to an embodiment of the present invention. As shown in fig. 8, the method for controlling the constant power of the motor includes the following steps:
s101, start.
S102, judging whether the detection window period is in. If yes, go to step S103; if not, continuing to judge.
S103, judging whether a valid zero-crossing signal is received or not. If yes, go to step S104; if not, continuing to judge.
S104, multiple detections prevent errors, for example, when three zero-crossing signals are received consecutively, step S105 is performed.
And S105, reversing.
S106, obtaining the voltage V of the direct current busdcAnd DC bus current Idc。
S107, direct current bus voltage VdcLPF processing (low pass filter processing) is carried out to obtain a given value V of the DC bus voltagedc *。
S108, according to the given value V of the DC bus voltagedc *Given power value P*Obtaining the given value i of the direct current bus current by looking up the tabledc *。
S109, setting a direct current bus current idc *With a DC bus current idcCurrent difference value △ i betweendcPI adjustment is performed to obtain the Duty signal Duty.
And S110, updating the PWM value.
S11, setting the time for masking the zero-crossing signal.
Therefore, during the zero-crossing processing period of the back electromotive force signal, the instruction current control power of PI control of the bus current is obtained by looking up the current feedback direct current bus voltage.
In summary, according to the constant power control method of the motor of the embodiment of the present invention, the dc bus voltage and the dc bus current of the motor are obtained, then the dc bus current given value of the motor is obtained by looking up the table according to the dc bus voltage and the power given value of the motor, the current difference between the dc bus current given value and the dc bus current is obtained, and the current difference is subjected to PI adjustment to obtain the duty ratio signal for controlling the motor, and the motor is subjected to constant power control according to the duty ratio signal. The method realizes the constant power control of the motor by carrying out PI control on the direct current bus current, does not increase the hardware cost, can realize the effects of large-scale power regulation and continuous control without using a position sensor, and can effectively solve the problem of poor control effect caused by the influence of environmental factors in the production process.
In addition, an embodiment of the present invention also proposes a non-transitory computer-readable storage medium on which a computer program is stored, which when executed by a processor implements the above-mentioned method.
By executing the constant power control method, the non-transitory computer-readable storage medium of the embodiment of the invention can realize the constant power control of the motor by performing the PI control on the direct current bus current, not only does not increase the hardware cost, but also can realize the effects of large-scale power regulation and continuous control without using a position sensor, and can effectively improve the problem of poor control effect caused by the influence of environmental factors in the production process.
Fig. 5 is a block schematic diagram of a constant power control arrangement for an electric machine according to one embodiment of the present invention. As shown in fig. 5, the constant power control apparatus of the motor includes a bus voltage obtaining module 201, a bus current obtaining module 202, a current setting module 203, a deviation obtaining module 204, a PI adjusting module 205, and a control module 206.
The bus voltage obtaining module 201 is used for obtaining a dc bus voltage V of the motordc(ii) a The bus current obtaining module 202 is used for obtaining the dc bus current i of the motordc(ii) a The current setting module 203 is used for setting the current according to the DC bus voltage VdcAnd given power value P of motor*Obtaining the direct current bus current given value i of the motor by looking up a tabledc *(ii) a The deviation obtaining module 204 is used for obtaining a given value i of the dc bus currentdc *With a DC bus current idcThe difference in current between; the PI regulation module 205 is configured to perform PI regulation on the current difference to obtain a Duty ratio signal Duty for controlling the motor; the control module 206 is used for accountingThe Duty signal Duty performs constant power control on the motor.
Specifically, as shown in fig. 3 and 5, when the motor is controlled at constant power, the bus voltage obtaining module 201 obtains the dc bus voltage V by sampling the voltage signal of the resistor voltage dividing circuitdcThe bus current obtaining module 202 obtains the dc bus current i by sampling a voltage signal on the dc bus sampling resistor and converting the voltage signal into a current signaldc. The current setting module 203 is based on the DC bus voltage VdcAnd given power value P of motor*Obtaining the direct current bus current given value i of the motor by looking up a table (as shown in table 1)dc *Then, the deviation obtaining module 204 (such as a subtracter) obtains the given value i of the DC bus currentdc *With a DC bus current idcCurrent difference value △ i betweendc＝idc *-idcAnd △ idc＝idc *-idcThe error amount is sent to a PI regulation module 205 (such as a PI regulator) as a negative feedback regulation, a signal for outputting a control pulse width, i.e., a Duty ratio signal Duty, is regulated by the PI regulation module 205, and then a control unit 206 (such as a PWM unit) outputs a driving signal to the three-phase bridge according to the Duty ratio signal Duty to perform on/off control on the switching tubes of the three-phase bridge, so as to finally obtain a required voltage to be supplied to the three-phase brushless dc motor, thereby realizing a power constant regulation function by means of stable control of the dc bus current.
Further, according to an embodiment of the present invention, as shown in fig. 5, the constant power control apparatus of the motor further includes: a filtering processing module 207 for processing the DC bus voltage VdcAnd performing low-pass filtering processing.
That is, the DC bus voltage V is obtained after samplingdcThen, the dc bus voltage V may be first filtered by the filtering module 207dcLow-pass filtering is carried out, and then the current setting module 203 carries out low-pass filtering according to the DC bus voltage V after the low-pass filteringdc *(can be called DC bus voltage given value V)dc *) Given power value P*By passingLooking up a table to obtain a given value i of the direct current bus currentdc *Therefore, the power control can be more stable, and the power pulsation is reduced.
Further, according to an embodiment of the present invention, as shown in fig. 9, the above-mentioned constant power control apparatus for an electric machine further includes a terminal voltage obtaining module 208 and a back electromotive force zero-crossing obtaining module 209, where the terminal voltage obtaining module 208 is configured to obtain a terminal voltage of the electric machine; the back electromotive force zero-crossing acquiring module 209 is used for acquiring a back electromotive force zero-crossing signal of the motor according to the end voltage of the motor; the control module 206 is further configured to control the motor to perform commutation according to the back electromotive force zero-crossing signal, and obtain a duty ratio signal for controlling the motor after the commutation is completed.
Specifically, the terminal voltage obtaining module 208 may obtain the terminal voltage U of the motor by sampling the voltage signal on the voltage transformeru、Uv、UwAnd then it is sent to the back electromotive force zero-crossing acquisition module 209 to acquire the back electromotive force zero-crossing signal of the motor (when the end voltage changes to 1/2V) through the back electromotive force zero-crossing acquisition module 209dcCan be used instead of the back emf zero crossing), which can be read by means of an external interrupt, the waveform of which is shown in fig. 6; the inquiry can also be performed by means of software timer interrupt, and the waveform of the inquiry is shown in fig. 7. It should be noted that, both the zero-crossing reading processes in the two modes have a certain window time, under normal conditions, in a non-detection window period, the software masks the zero-crossing signal of the back electromotive force, and in a detection window period, the control module 206 receives the zero-crossing signal and starts to perform the zero-crossing process and the corresponding PWM output after receiving the effective zero-crossing signal.
Specifically, when the processed back electromotive force zero-crossing signal changes from negative to positive, the zero-crossing process is triggered by an external interrupt or a turnover signal queried by a software timer, during the zero-crossing process, the control module 206 controls the motor to perform commutation and PWM output, and after the commutation is completed, the duty ratio signal required by the next control period is obtained according to the detected direct-current bus voltage and direct-current bus current through the PI regulation module 205 and the like. After the commutation is finished, the time is 60 degrees from the next commutation, so that enough time is provided for finishing the control operation of table lookup and current loop.
It should be noted that details not disclosed in the constant power control apparatus of the motor according to the embodiment of the present invention refer to details disclosed in the constant power control method of the motor according to the embodiment of the present invention, and detailed descriptions thereof are omitted here.
According to the constant power control device of the motor, the bus voltage obtaining module is used for obtaining the direct current bus voltage of the motor, the bus current obtaining module is used for obtaining the direct current bus current of the motor, and the current setting module is used for obtaining the direct current bus current set value of the motor through table lookup according to the direct current bus voltage and the power set value of the motor. Then, a current difference value between the given value of the direct current bus current and the direct current bus current is obtained through a deviation obtaining module, PI regulation is carried out on the current difference value through a PI regulation module to obtain a duty ratio signal used for controlling the motor, and constant power control is carried out on the motor through a control module according to the duty ratio signal. The device is through carrying out PI control to direct current bus current in order to realize the constant power control to the motor, not only can not increase the hardware cost, need not to use position sensor moreover, can realize the effect of power control and continuous control on a large scale, can effectively improve the poor problem of control effect that leads to because of environmental factor influences in the production process simultaneously.
In addition, the embodiment of the invention also provides a motor which comprises the constant power control device. The motor may be a three-phase brushless dc motor.
According to the motor provided by the embodiment of the invention, through the constant power control device, the constant power control of the motor can be realized by carrying out PI control on the direct current bus current, so that the hardware cost is not increased, the effects of large-scale power regulation and continuous control can be realized without using a position sensor, and the problem of poor control effect caused by environmental factors in the production process can be effectively solved.
In addition, the embodiment of the invention also provides a dust collector which comprises the motor.
According to the dust collector provided by the embodiment of the invention, the motor can realize constant-power operation.
It should be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.
In addition, in the description of the present invention, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, should not be construed as limiting the present invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (9)
1. A constant power control method of a three-phase brushless direct current motor is characterized by comprising the following steps:
s1, acquiring direct current bus voltage and direct current bus current of the three-phase brushless direct current motor, wherein the direct current bus current idcIs equal to the three-phase output current instantaneous value i of the three-phase brushless DC motoru、ivAnd iwOr the square sum of the root of the direct bus current idcIs equal to the three-phase output current instantaneous value i of the three-phase brushless DC motoru、ivAnd iwThe square sum of the root of the dq axis current instantaneous value is converted into a two-phase rotating coordinate system through rotation;
s2, obtaining the direct current bus current given value of the motor through table look-up according to the direct current bus voltage and the power given value of the three-phase brushless direct current motor;
s3, acquiring a current difference value between the given value of the direct current bus current and the direct current bus current;
s4, performing PI adjustment on the current difference to obtain a duty ratio signal for controlling the three-phase brushless dc motor, and performing constant power control on the three-phase brushless dc motor according to the duty ratio signal, further including:
acquiring the end voltage of the three-phase brushless direct current motor through a voltage sampling circuit;
acquiring a back electromotive force zero-crossing signal of the three-phase brushless direct current motor according to the end voltage of the three-phase brushless direct current motor;
and controlling the three-phase brushless direct current motor to commutate according to the back electromotive force zero-crossing signal of the three-phase brushless direct current motor, and acquiring a duty ratio signal for controlling the three-phase brushless direct current motor after the commutation is finished, wherein the real-time back electromotive force zero-crossing signal is inquired by external interruption or software timing interruption in a detection window period.
2. The constant power control method of a three-phase brushless dc motor according to claim 1, wherein when the dc bus current set value of the three-phase brushless dc motor is obtained by table lookup based on the dc bus voltage and the power set value of the three-phase brushless dc motor, the dc bus voltage is further subjected to low pass filtering processing.
3. The method according to claim 1, wherein the dc bus current of the three-phase brushless dc motor is obtained by a dc bus sampling resistor.
4. A non-transitory computer-readable storage medium having stored thereon a computer program, wherein the computer program, when executed by a processor, implements the method of any one of claims 1-3.
5. A constant power control device of a three-phase brushless DC motor, comprising:
the bus voltage acquisition module is used for acquiring the direct-current bus voltage of the three-phase brushless direct-current motor;
a bus current obtaining module for obtaining the DC bus current of the three-phase brushless DC motor, wherein the DC bus current idcIs equal to the three-phase output current instantaneous value i of the three-phase brushless DC motoru、ivAnd iwOr the square sum of the root of the direct bus current idcIs equal to the three-phase output current instantaneous value i of the three-phase brushless DC motoru、ivAnd iwThe square sum of the root of the dq axis current instantaneous value is converted into a two-phase rotating coordinate system through rotation;
the current setting module is used for obtaining a direct-current bus current set value of the three-phase brushless direct-current motor through table lookup according to the direct-current bus voltage and the power set value of the three-phase brushless direct-current motor;
the deviation obtaining module is used for obtaining a current difference value between the given value of the direct current bus current and the direct current bus current;
the PI adjusting module is used for carrying out PI adjustment on the current difference value to obtain a duty ratio signal for controlling the three-phase brushless direct current motor;
the control module is used for carrying out constant power control on the three-phase brushless direct current motor according to the duty ratio signal,
further comprising:
the terminal voltage acquisition module is used for acquiring the terminal voltage of the three-phase brushless direct current motor;
the back electromotive force zero-crossing acquisition module is used for acquiring a back electromotive force zero-crossing signal of the three-phase brushless direct current motor according to the end voltage of the three-phase brushless direct current motor;
the control module is further configured to control the three-phase brushless direct current motor to perform commutation according to the back electromotive force zero-crossing signal, and obtain a duty ratio signal for controlling the three-phase brushless direct current motor after the commutation is completed.
6. The constant power control apparatus of a three-phase brushless dc motor according to claim 5, further comprising:
and the filtering processing module is used for carrying out low-pass filtering processing on the direct-current bus voltage.
7. The constant-power control device for the motor according to claim 5, wherein the bus current obtaining module obtains the dc bus current of the three-phase brushless dc motor through a dc bus sampling resistor.
8. A three-phase brushless DC motor, characterized in that it comprises a constant power control device according to any of claims 5-7.
9. A vacuum cleaner comprising a three-phase brushless dc motor according to claim 8.
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| CN108923717B (en) * | 2018-08-07 | 2020-04-21 | 珠海格力电器股份有限公司 | Handheld dust collector, motor and method and device for quickly adjusting power of handheld dust collector |
| CN110171018A (en) * | 2019-05-25 | 2019-08-27 | 塞伯睿机器人技术（长沙）有限公司 | Robot motor starts control device |
| CN110138311B (en) * | 2019-06-18 | 2020-06-30 | 宁波奥克斯电气股份有限公司 | Control method and circuit for constant-power preheating of compressor and air conditioner |
| CN113131809B (en) * | 2019-12-31 | 2023-04-07 | 广东美的白色家电技术创新中心有限公司 | Zero crossing point detection device and method for brushless direct current motor |
| CN113131806A (en) * | 2019-12-31 | 2021-07-16 | 广东美的白色家电技术创新中心有限公司 | Control device and method of brushless direct current motor |
| CN113131805B (en) * | 2019-12-31 | 2023-03-10 | 广东美的白色家电技术创新中心有限公司 | Control device and method of brushless direct current motor |
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