CN114944786A - Control method and system of synchronous motor - Google Patents
Control method and system of synchronous motor Download PDFInfo
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- CN114944786A CN114944786A CN202210625982.8A CN202210625982A CN114944786A CN 114944786 A CN114944786 A CN 114944786A CN 202210625982 A CN202210625982 A CN 202210625982A CN 114944786 A CN114944786 A CN 114944786A
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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
- H02P5/00—Arrangements specially adapted for regulating or controlling the speed or torque of two or more electric motors
- H02P5/46—Arrangements specially adapted for regulating or controlling the speed or torque of two or more electric motors for speed regulation of two or more dynamo-electric motors in relation to one another
- H02P5/50—Arrangements specially adapted for regulating or controlling the speed or torque of two or more electric motors for speed regulation of two or more dynamo-electric motors in relation to one another by comparing electrical values representing the speeds
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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
- H02P2205/00—Indexing scheme relating to controlling arrangements characterised by the control loops
- H02P2205/01—Current loop, i.e. comparison of the motor current with a current reference
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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
- H02P2205/00—Indexing scheme relating to controlling arrangements characterised by the control loops
- H02P2205/07—Speed loop, i.e. comparison of the motor speed with a speed reference
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/60—Other road transportation technologies with climate change mitigation effect
- Y02T10/72—Electric energy management in electromobility
Abstract
The invention discloses a control method and a control system of a synchronous motor. The control method of the synchronous motor is applied to a control system of the synchronous motor, and comprises the following steps: acquiring a real-time feedback rotating speed of the motor; acquiring a speed setting instruction input by a user; determining a speed control instruction based on the speed setting instruction and the real-time feedback rotating speed so that the driving piece drives the motor to rotate based on the speed control instruction; acquiring the current running current of the motor; and adjusting the speed control instruction based on the current running current so as to enable the driving part to drive the motors to rotate based on the adjusted speed control instruction until the difference value of the current feedback rotating speeds of the motors is smaller than a first preset difference value. By adopting the scheme, the balance of the running current of the motor of each work is ensured, the service life of the motor is prolonged, the motor can be flexibly applied to different motor coupling control fields, and the number of the coupling motors is not limited.
Description
Technical Field
The embodiment of the invention relates to the technical field of motor control, in particular to a control method and a control system of a synchronous motor.
Background
The motor coupling control is widely applied in the field of asynchronous motors, a plurality of asynchronous motors drag loads to operate simultaneously, and due to the slip of the asynchronous motors, the established control function can be realized easily. In the field of synchronous motors, because of no influence of slip, synchronous control of a plurality of motors can realize corresponding control functions only by position feedback of a position sensor. Because the encoder is expensive and the signal is easy to be interfered, the coupling control of the synchronous motor can only be used for the synchronous control application of the low-power synchronous motor in the high-precision occasion. In the related art, when a plurality of motors control a load, the output current of each motor is unbalanced, so that each motor generates different heat, and the motor with larger heat generation has shorter service life than the motor with smaller heat generation and is easy to damage.
Disclosure of Invention
The invention provides a control method and a control system of a synchronous motor, which aim to achieve the effect of prolonging the service life of the motor.
According to one aspect of the invention, a control method of a synchronous motor is provided, the control method of the synchronous motor is applied to a control system of the synchronous motor, the control system of the synchronous motor comprises a coupling controller, a plurality of driving parts and a plurality of motors, and the driving parts and the motors are connected in a one-to-one correspondence manner; the coupling controller is electrically connected with the driving piece; the control method of the synchronous motor comprises the following steps:
acquiring a real-time feedback rotating speed of the motor;
acquiring a speed setting instruction input by a user;
determining a speed control instruction based on the speed setting instruction and the real-time feedback rotating speed so that the driving piece drives the motor to rotate based on the speed control instruction;
acquiring the current running current of the motor;
adjusting the speed control instruction based on the current running current so that the driving part drives the motors to rotate based on the adjusted speed control instruction until the difference value of the current feedback rotating speeds of the motors is smaller than a first preset difference value;
and increasing the speed control instruction based on the difference value between the current feedback rotating speed of the motor and the speed control instruction so as to enable the driving part to drive the motor to rotate based on the increased speed control instruction until the difference value between the speed setting instruction and the real-time feedback rotating speed is smaller than a second preset difference value.
In an optional embodiment of the invention, said adjusting said speed control command based on said present operating current comprises:
adjusting the speed control command in a negative feedback form based on the current operating current.
In an alternative embodiment of the present invention, said adjusting said speed control command in a negative feedback form based on said present operating current comprises:
reducing the speed control command by a preset magnitude based on the current operating current by:
F＝I*K；
wherein I is the current operating current; k is a reduction ratio; f is a predetermined magnitude of the decrease.
In an optional embodiment of the invention, said determining a speed control command based on said speed setting command and said real-time feedback rotational speed comprises:
determining a speed difference value between the speed setting instruction and the real-time feedback rotating speed;
and determining a speed control command through a PID control algorithm based on the speed difference value.
In an optional embodiment of the present invention, the expression of the PID control algorithm is:
kp is a proportional constant, Ti is an integral time constant, Td is a derivative time constant, u (t) is an output signal of a PID control algorithm, and e (t) is a speed difference value.
In an alternative embodiment of the invention, the drive comprises a frequency converter;
the acquiring of the real-time feedback rotating speed of the motor comprises the following steps:
and acquiring the real-time feedback rotating speed of the motor estimated by the frequency converter.
In an optional embodiment of the present invention, the determining a speed control command based on the speed setting command and the real-time feedback rotation speed to enable the driving member to drive the motor to rotate based on the speed control command includes:
determining a speed control instruction based on the speed setting instruction and the real-time feedback rotating speed so that the frequency converter outputs a driving frequency based on the speed control instruction to drive the motor to rotate;
correspondingly, the adjusting the speed control command based on the current running current to enable the driving part to drive the motor to rotate based on the adjusted speed control command includes:
and adjusting the speed control instruction based on the current running current so that the frequency converter outputs a driving frequency based on the adjusted speed control instruction to drive the motor to rotate.
According to another aspect of the present invention, there is provided a control system of a synchronous machine, comprising a coupling controller, a drive, and a motor;
the driving parts are used for driving the motors to rotate;
the coupling controller is electrically connected with the driving piece;
the coupling controller is configured to execute a control method of a synchronous motor according to any one of the embodiments of the present invention.
In an alternative embodiment of the invention, the drive comprises a frequency converter;
the frequency converter is used for outputting driving frequency to drive the motor to rotate; and/or the frequency converter is used for estimating the real-time feedback rotating speed of the motor.
In an alternative embodiment of the present invention, the coupling controller comprises a PLC.
According to the technical scheme of the embodiment of the invention, the real-time feedback rotating speed of the motor is obtained; acquiring a speed setting instruction input by a user; determining a speed control instruction based on the speed setting instruction and the real-time feedback rotating speed so that the driving piece drives the motor to rotate based on the speed control instruction; further acquiring the current running current of the motor; adjusting the speed control instruction based on the current running current so that the driving part drives the motors to rotate based on the adjusted speed control instruction until the difference value of the current feedback rotating speeds of the motors is smaller than a first preset difference value; and finally, increasing the speed control instruction based on the difference value between the current feedback rotating speed of the motor and the speed control instruction so that the driving part drives the motor to rotate based on the increased speed control instruction until the difference value between the speed setting instruction and the real-time feedback rotating speed is smaller than a second preset difference value. The speed control instruction can be changed according to the current running current of the motor, so that the load of each motor tends to be balanced, when the load of a plurality of motors is controlled, the output current of each motor has unbalanced phenomenon, each motor is caused to generate heat differently, the service life of the motor which generates heat is shortened and the motor is damaged easily compared with the motor which generates heat and is small, the balance of the running current of the motor which works at each time is ensured, and the service life of the motor is prolonged. The motor coupling control method can be flexibly applied to different motor coupling control fields without limiting the number of coupling motors.
It should be understood that the statements in this section do not necessarily identify key or critical features of the embodiments of the present invention, nor do they necessarily limit the scope of the invention. Other features of the present invention will become apparent from the following description.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a block diagram of a control system of a synchronous motor, to which a control method of a synchronous motor according to an embodiment of the present invention is applied;
fig. 2 is a flowchart of a control method of a synchronous motor according to an embodiment of the present invention;
fig. 3 is a block diagram of a control system of another synchronous motor to which a control method of a synchronous motor according to an embodiment of the present invention is applied;
fig. 4 is a flowchart of a control method of a synchronous motor according to a second embodiment of the present invention.
Wherein: 1. a coupling controller; 2. a drive member; 21. a frequency converter; 3. an electric motor.
Detailed Description
In order to make the technical solutions of the present invention better understood, 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 only a part of the embodiments of the present invention, and not all of the embodiments. 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.
It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
Example one
Fig. 1 is a block diagram of a control system of a synchronous motor applied to a control method of a synchronous motor according to an embodiment of the present invention, and fig. 2 is a flowchart of the control method of the synchronous motor according to the embodiment of the present invention, where this embodiment is applicable to a case of performing coupling control on a plurality of motors, and the control method of the synchronous motor is applied to the control system of the synchronous motor, as shown in fig. 1, the control system of the synchronous motor includes a coupling controller, a driving member, and a plurality of motors, where the driving member and the motors are connected in a one-to-one correspondence manner; the coupling controller is electrically connected with the driving member. The input of the coupling controller is the real-time feedback rotating speed of the motor and the speed setting instruction input by the user, and the output of the coupling controller is the input of the driving part. The driving member drives the motor to rotate based on the input. In the present embodiment, the control method of the synchronous motor may be applied to a coupling controller that performs the control method of the synchronous motor by a hardware and/or software method. As shown in fig. 2, the method for controlling the synchronous motor includes:
and S110, acquiring the real-time feedback rotating speed of the motor.
The real-time feedback rotating speed of the motor refers to an actual rotating speed value of the motor in the current running state.
And S120, acquiring a speed setting instruction input by a user.
The speed setting instruction input by the user refers to a rotating speed value which is set by the user and is required to be reached by the motor.
And S130, determining a speed control instruction based on the speed setting instruction and the real-time feedback rotating speed so that the driving piece drives the motor to rotate based on the speed control instruction.
The speed control command is a command for indicating the rotating speed of the driving part driving motor. Because the number of the driving parts is multiple, each driving part controls the corresponding connected motor to operate at the rotating speed corresponding to the speed control instruction according to the speed control instruction.
And S140, acquiring the current running current of the motor.
Here, the current running current refers to a current when the current motor is running. When multiple motors control a load, the current operating current for each motor may be different.
S150, adjusting the speed control command based on the current running current so that the driving part drives the motors to rotate based on the adjusted speed control command until the difference value of the current feedback rotating speeds of the motors is smaller than a first preset difference value.
The current feedback rotating speed refers to the current actual rotating speed of the motors, and when the load of each motor tends to be balanced, the actual rotating speeds of the motors tend to be equal, namely, the difference value of the current feedback rotating speeds of the motors is smaller than a first preset difference value.
When the driving part controls the correspondingly connected motors to operate according to the speed control instruction, the speed control instructions received by the motors are the same, but the current operating currents are different. At the moment, the corresponding speed control instruction is adjusted through the current running current of each motor, so that the speed control instruction can be changed according to the current running current of the motors, the load of each motor tends to be balanced, and the service life of the motors is prolonged.
And S160, increasing the speed control instruction based on the difference value between the current feedback rotating speed of the motor and the speed control instruction so as to enable the driving piece to drive the motor to rotate based on the increased speed control instruction until the difference value between the speed setting instruction and the real-time feedback rotating speed is smaller than a second preset difference value.
In the process, the actual load rotating speed is smaller than the set rotating speed due to the fact that the operating rotating speed of the motor is reduced due to the increase of the current, namely when the load of each motor tends to be balanced, the current feedback rotating speed of the motor is smaller than the speed setting instruction. Meanwhile, due to the requirement of precision, the rotating speed of the actual load is difficult to be completely consistent with the set rotating speed, certain floating exists, when the difference value between the speed setting instruction and the real-time feedback rotating speed is smaller than a second preset difference value, the difference value between the speed setting instruction and the real-time feedback rotating speed is smaller and tends to be consistent, the size of the second preset difference value reflects the control precision, specific limitation is not made, and the setting can be carried out according to the use requirement.
When the load of each motor tends to be balanced, the current feedback rotating speed of the motor is smaller than a speed setting instruction, and the speed control instruction is increased based on the difference value between the current feedback rotating speed of the motor and the speed control instruction, so that the driving part drives the motor to rotate based on the increased speed control instruction, the rotating speed of the actual load can be consistent with the set rotating speed, and the final control purpose is achieved.
For example, in a specific embodiment, assuming that the speed setting command is 1000 revolutions, the speed control command controls the driving member to drive the motor to rotate at a requirement of 1000 revolutions, then during the rotation of the motor, due to imbalance of the load, the rotation speeds and currents of different motors may be different, and at this time, through continuous adjustment, the load may be in a balanced state, however, when the load of each motor tends to be balanced, the current feedback rotation speed of the motor may be smaller than the speed setting command, that is, each motor may be stabilized at about 950 revolutions. It is shown that when a 1000-turn command is given to request to send a speed control command, the actual rotation speed during load balancing, that is, the current feedback rotation speed, can only be about 950 turns, and cannot achieve the control purpose. At this time, the speed control instruction is increased based on the difference between the current feedback rotating speed and the speed control instruction, namely, the speed control instruction is increased based on the difference of 50 revolutions between 1000 revolutions and 950 revolutions, so that the speed control instruction is sent to control the driving part to drive the motor to rotate according to the requirement of 1050 revolutions, and therefore when the load of each motor tends to be balanced, the motor can reach 1000 revolutions of the speed setting instruction, and the final control purpose is achieved.
According to the scheme, the real-time feedback rotating speed of the motor is obtained; acquiring a speed setting instruction input by a user; determining a speed control instruction based on the speed setting instruction and the real-time feedback rotating speed so that the driving piece drives the motor to rotate based on the speed control instruction; further acquiring the current running current of the motor; adjusting the speed control instruction based on the current running current so that the driving part drives the motors to rotate based on the adjusted speed control instruction until the difference value of the current feedback rotating speeds of the motors is smaller than a first preset difference value; and finally, increasing the speed control instruction based on the difference value between the current feedback rotating speed of the motor and the speed control instruction so that the driving part drives the motor to rotate based on the increased speed control instruction until the difference value between the speed setting instruction and the real-time feedback rotating speed is smaller than a second preset difference value. The speed control instruction can be changed according to the current running current of the motor, so that the load of each motor tends to be balanced, when the load of a plurality of motors is controlled, the output current of each motor has unbalanced phenomenon, each motor is caused to generate heat differently, the service life of the motor which generates heat is shortened and the motor is damaged easily compared with the motor which generates heat and is small, the balance of the running current of the motor which works at each time is ensured, and the service life of the motor is prolonged. The motor coupling control method can be flexibly applied to different motor coupling control fields without limiting the number of coupling motors.
In an optional embodiment of the present invention, the determining a speed control command based on the speed setting command and the real-time feedback rotation speed comprises:
and determining a speed difference value between the speed setting instruction and the real-time feedback rotating speed.
And determining a speed control command through a PID control algorithm based on the speed difference value.
The speed difference value reflects the deviation between the actual rotating speed value of the motor in the current operating state and the rotating speed value which is set by the user and is to be reached by the motor.
PID is as follows: abbreviations for proportionality, Integral, Differential. As the name suggests, the PID control algorithm is a control algorithm which combines three links of proportion, integration and differentiation into a whole, is the most mature technology and the most widely applied control algorithm in a continuous system, appears in 30 to 40 years of the 20 th century, and is suitable for occasions where a controlled object model is not clearly understood. The analysis of practical operation experience and theory shows that the control law can obtain satisfactory effect when used for controlling a plurality of industrial processes. The essence of the PID control is that the operation is performed according to the function relationship of proportion, integral and differential according to the input deviation value, and the operation result is used to control the output.
Therefore, with the PID control algorithm, if the load of the motor increases, the rotational speed of the motor decreases, and the deviation between the speed setting command and the real-time feedback rotational speed increases (i.e., the speed difference increases), so that the speed control command of the driving member increases, increasing the rotational speed of the motor, and thereby decreasing the deviation between the speed setting command and the real-time feedback rotational speed. If the load of the motor is reduced, the rotating speed of the motor is increased, the deviation between the speed setting instruction and the real-time feedback rotating speed is reduced (namely, the speed difference value is reduced), the speed control instruction passing through the coupling controller is reduced, the rotating speed of the motor is reduced, and therefore the deviation between the speed setting instruction and the real-time feedback rotating speed is reduced. After continuous adjustment, the rotating speed is fed back in real time to approach the speed setting instruction. Thereby achieving the purpose of controlling the rotating speed of the motor.
Illustratively, the expression of the PID control algorithm is:
kp is a proportional constant, Ti is an integral time constant, Td is a derivative time constant, u (t) is an output signal of a PID control algorithm, and e (t) is a speed difference value.
The output signal of the PID control algorithm is a current control instruction, and the current control instruction can be conveniently determined according to the speed difference value through the expression, so that the control of the rotating speed of the motor is realized.
In an alternative embodiment of the invention, as shown in fig. 3, the drive member (not shown in fig. 3) comprises a frequency converter.
The acquiring of the real-time feedback rotating speed of the motor comprises the following steps: and acquiring the real-time feedback rotating speed of the motor estimated by the frequency converter.
The Variable-frequency Drive (VFD) is an electric control device that applies a frequency conversion technology and a microelectronic technology and controls an ac motor by changing a frequency of a working power supply of the motor. The main circuits of frequency converters can be broadly divided into two categories: the voltage type is a frequency converter for converting direct current of a voltage source into alternating current, and the filter of a direct current loop is a capacitor. The current type is a frequency converter for converting dc of a current source into ac, and the dc loop filter is an inductor.
Because the rotating speed and the frequency of the motor have a certain relation, the formula of the rotating speed and the frequency of the motor is as follows: n is 60f/p, and the frequency converter changes the working power supply frequency of the motor when driving the motor to rotate, so the rotating speed of the motor can be estimated through the frequency converter, namely the rotating speed is fed back in real time.
According to the scheme, the real-time feedback rotating speed of the motor estimated by the frequency converter is obtained, and then a speed setting instruction input by a user is obtained; determining a speed control instruction based on the speed setting instruction and the real-time feedback rotating speed so that the driving piece drives the motor to rotate based on the speed control instruction; acquiring the current running current of the motor; and finally, adjusting the speed control command based on the current running current so that the driving part drives the motor to rotate based on the adjusted speed control command. Therefore, the speed loop can be completed through the coupling controller, the result after PID operation is used as the input of the current loop formed by the frequency converters, and each frequency converter independently controls the motor to operate in the current loop, so that the problem of conflict between the motor rotating speeds possibly caused by the simultaneous operation of a plurality of frequency converters in the speed loop is avoided, the coupling control of a plurality of motors without position sensors is solved, the cost of the coupling control is reduced, and the reliability of the system is improved. Meanwhile, the actual rotating speed of the load can be consistent with the set rotating speed, and the final control purpose is achieved.
On the basis of the above embodiment, the determining a speed control command based on the speed setting command and the real-time feedback rotating speed to make the driving member drive the motor to rotate based on the speed control command includes:
and determining a speed control instruction based on the speed setting instruction and the real-time feedback rotating speed so that the frequency converter outputs a driving frequency based on the speed control instruction to drive the motor to rotate.
Wherein, because the rotational speed of motor has certain relation with the frequency, the formula of motor rotational speed and frequency: when the frequency converter drives the motor to rotate, the frequency of the working power supply of the motor is changed, so that the motor can be rotated by outputting the corresponding driving frequency through the frequency converter based on the speed control instruction, and the rotating speed of the motor can be adjusted by adjusting the output driving frequency.
On the basis of the above embodiment, the adjusting the speed control command based on the current operating current to make the driving member drive the motor to rotate based on the adjusted speed control command includes:
and adjusting the speed control instruction based on the current running current so that the frequency converter outputs a driving frequency based on the adjusted speed control instruction to drive the motor to rotate.
The frequency converter adjusts the rotating speed of the motor by adjusting the driving frequency, so that after the speed control command is adjusted, the frequency converter outputs the driving frequency based on the adjusted speed control command, and the rotating speed of the motor can be changed.
Example two
Fig. 4 is a flowchart of a control method of a synchronous motor according to a second embodiment of the present invention, where the second embodiment is improved on the basis of the first embodiment, and optionally, the adjusting the speed control command based on the current operating current includes: adjusting the speed control command in a negative feedback form based on the current operating current. As shown in fig. 4, the method for controlling the synchronous motor includes:
and S210, acquiring the real-time feedback rotating speed of the motor.
And S220, acquiring a speed setting instruction input by a user.
And S230, determining a speed control command based on the speed setting command and the real-time feedback rotating speed, so that the driving piece drives the motor to rotate based on the speed control command.
And S240, acquiring the current running current of the motor.
And S250, adjusting the speed control command in a negative feedback mode based on the current running current so as to enable the driving part to drive the motors to rotate based on the adjusted speed control command until the difference value of the current feedback rotating speeds of the motors is smaller than a first preset difference value.
The negative feedback means that the current running current is superposed on the speed control instruction to weaken the speed control instruction, and the larger the current running current is, the larger the reduction amplitude of the speed control instruction is.
And S260, increasing the speed control instruction based on the difference value between the current feedback rotating speed of the motor and the speed control instruction so that the driving part drives the motor to rotate based on the increased speed control instruction until the difference value between the speed setting instruction and the real-time feedback rotating speed is smaller than a second preset difference value.
According to the scheme, when the speed setting instruction is set manually, the speed control instruction currently sent to each driving piece is calculated according to the speed setting instruction and the real-time feedback rotating speed. And the driving parts control the rotating speed corresponding to the motor running speed control instruction according to the issued speed control instruction, and at the moment, the speeds of a plurality of motors are the same, but the currents are different.
According to the running currents of a plurality of motors, the current running currents of the motors are superposed on respective speed control commands in a negative feedback mode, when the current of a certain motor is increased, the actual speed control command of the certain motor is reduced, and at the moment, the speed of the other motors is unchanged, the speed of the motor is reduced, so that the actual load of the motor is reduced, and the current of the motor is reduced.
The reduction amplitude of the speed with the largest load of the motors is the largest, the reduction amplitude of the load with the small load is smaller, and finally the loads of the motors tend to be balanced through a continuous adjusting process. But this is because the reduction in the operating speed of the motor due to the increase in the current causes the actual load speed to be less than the set speed. At the moment, according to the load reduction amplitude, namely the difference between the speed setting instruction and the real-time feedback rotating speed, the speed setting of the whole system is increased again, so that the actual rotating speed of the load is consistent with the set rotating speed, and the final control purpose is achieved.
In an alternative embodiment of the present invention, said adjusting said speed control command in a negative feedback form based on said present operating current comprises:
reducing the speed control command by a preset magnitude based on the current operating current by:
F＝I*K。
wherein I is the current operating current; k is a reduction ratio; f is a predetermined magnitude of the decrease.
In the mode, the amplitude of the speed control instruction with heavier load is reduced more, the speed control instruction is reduced to lighten the load, the amplitude of the speed control instruction with lighter load is reduced lower, and the continuous adjustment can balance the currents among the motors.
In addition, in a specific embodiment, when the driving member is a frequency converter, since the frequency converter changes the rotation speed of the motor by changing the frequency, K is the frequency reduction ratio of the setting parameter, and F is the amplitude of the frequency reduction.
EXAMPLE III
The third embodiment of the invention discloses a control system of a synchronous motor, which comprises a coupling controller 1, a driving part 2 and a motor 3, as shown in fig. 1.
The quantity of driving piece 2 and motor 3 is a plurality of, and the one-to-one connection, and driving piece 2 is used for driving motor 3 to rotate.
The coupling controller 1 is electrically connected to the driving member 2, and the coupling controller 1 is configured to execute a control method of the synchronous motor according to any embodiment of the present invention.
The input of the coupling controller is the real-time feedback rotating speed of the motor and the speed setting instruction input by the user, and the output of the coupling controller is the input of the driving part. The drive member drives the motor to rotate based on the input.
According to the scheme, the coupling controller 1 and the driving part 2 are arranged, the coupling controller 1 is electrically connected with the driving part 2, and the coupling controller 1 obtains the real-time feedback rotating speed of the motor 3; acquiring a speed setting instruction input by a user; determining a speed control instruction based on the speed setting instruction and the real-time feedback rotating speed so that the driving part 2 drives the motor 3 to rotate based on the speed control instruction; finally, the current running current of the motor 3 is obtained; adjusting a speed control instruction based on the current running current so that the driving part 2 drives the motors 3 to rotate based on the adjusted speed control instruction until the difference value of the current feedback rotating speeds of the motors 3 is smaller than a first preset difference value; and increasing the speed control instruction based on the difference between the current feedback rotating speed of the motor 3 and the speed control instruction, so that the driving part 2 drives the motor 3 to rotate based on the increased speed control instruction until the difference between the speed setting instruction and the real-time feedback rotating speed is smaller than a second preset difference. The balance of the running current of each working motor 3 is ensured, and the service life of the motor 3 is prolonged. The motor coupling control device can be flexibly applied to the field of coupling control of different motors 3, and the number of the coupled motors 3 is not limited.
In an alternative embodiment of the invention, the coupling controller 1 is also arranged to adjust the speed control command in negative feedback form based on the current operating current.
On the basis of the above embodiment, the coupling controller 1 is further configured to decrease the speed control command by a preset magnitude based on the current operating current by the following formula:
F＝I*K。
wherein I is the current operating current; k is a reduction ratio; f is a predetermined magnitude of the decrease.
In an alternative embodiment of the present invention, the coupling controller 1 is further configured to determine a speed difference between the speed setting command and the real-time feedback rotational speed; and determining a speed control command through a PID control algorithm based on the speed difference.
Illustratively, the expression for the PID control algorithm is:
kp is a proportional constant, Ti is an integral time constant, Td is a derivative time constant, u (t) is an output signal of a PID control algorithm, and e (t) is a speed difference value.
In an alternative embodiment of the invention, as shown in fig. 3, the drive 2 (not shown in fig. 3) comprises a frequency converter 21, which frequency converter 21 is also used for estimating the real-time feedback rotational speed of the motor 3; the coupling controller 1 is also used for obtaining the real-time feedback rotating speed of the motor 3 estimated by the frequency converter 21. The Variable-frequency Drive (VFD) 21 is a power control device that applies a frequency conversion technique and a microelectronic technique and controls the ac motor by changing the operating power supply frequency of the motor 3. The main circuits of the frequency converter 21 can be broadly divided into two categories: the voltage type is an inverter 21 for converting dc from a voltage source into ac, and the filter of the dc circuit is a capacitor. The current type is an inverter 21 for converting a direct current of a current source into an alternating current, and a direct current loop filter thereof is an inductor.
Because the rotating speed and the frequency of the motor 3 have a certain relation, the formula of the rotating speed and the frequency of the motor 3 is as follows: since the frequency converter 21 drives the motor 3 to rotate, the frequency of the operating power supply of the motor 3 is changed, and the frequency converter 21 can estimate the rotation speed of the motor 3, i.e., the real-time feedback rotation speed, and since the coupling controller 1 is electrically connected to the driving member 2, the coupling controller 1 can obtain the real-time feedback rotation speed estimated by the frequency converter 21.
In an alternative embodiment of the invention, the coupling controller 1 comprises a PLC.
Among them, plc (programmable Logic controller) refers to a programmable Logic controller, which is a digital operation electronic system specially designed for application in industrial environment. It uses a programmable memory, in which the instructions for implementing logical operation, sequence control, timing, counting and arithmetic operation are stored, and utilizes digital or analog input and output to control various mechanical equipments or production processes. Therefore, by making the coupling controller 1 include a PLC, the control method of the synchronous motor according to any of the embodiments of the present invention can be conveniently performed to realize the coupling control of the plurality of motors 3.
It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments illustrated herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims (10)
1. The control method of the synchronous motor is characterized by being applied to a control system of the synchronous motor, wherein the control system of the synchronous motor comprises a coupling controller, a driving part and a plurality of motors, and the driving part and the motors are respectively connected in a one-to-one correspondence manner; the coupling controller is electrically connected with the driving piece; the control method of the synchronous motor comprises the following steps:
acquiring a real-time feedback rotating speed of the motor;
acquiring a speed setting instruction input by a user;
determining a speed control instruction based on the speed setting instruction and the real-time feedback rotating speed so that the driving piece drives the motor to rotate based on the speed control instruction;
acquiring the current running current of the motor;
adjusting the speed control instruction based on the current running current so that the driving part drives the motors to rotate based on the adjusted speed control instruction until the difference value of the current feedback rotating speeds of the motors is smaller than a first preset difference value;
and increasing the speed control instruction based on the difference value between the current feedback rotating speed of the motor and the speed control instruction so as to enable the driving part to drive the motor to rotate based on the increased speed control instruction until the difference value between the speed setting instruction and the real-time feedback rotating speed is smaller than a second preset difference value.
2. The method of controlling a synchronous machine according to claim 1, wherein said adjusting the speed control command based on the present operating current comprises:
adjusting the speed control command in a negative feedback form based on the current operating current.
3. The method of claim 2, wherein said adjusting the speed control command in a negative feedback fashion based on the current operating current comprises:
reducing the speed control command by a preset magnitude based on the current operating current by:
F＝I*K；
wherein I is the current operating current; k is a reduction ratio; f is a predetermined magnitude of the decrease.
4. The control method of a synchronous machine according to any one of claims 1 to 3, wherein said determining a speed control command based on said speed setting command and said real-time feedback rotational speed comprises:
determining a speed difference value between the speed setting instruction and the real-time feedback rotating speed;
and determining a speed control command through a PID control algorithm based on the speed difference value.
5. The control method of the synchronous motor according to claim 4, wherein the expression of the PID control algorithm is:
kp is a proportional constant, Ti is an integral time constant, Td is a derivative time constant, u (t) is an output signal of a PID control algorithm, and e (t) is a speed difference value.
6. The control method of a synchronous motor according to any one of claims 1 to 3, characterized in that the drive member includes a frequency converter;
the acquiring of the real-time feedback rotating speed of the motor comprises the following steps:
and acquiring the real-time feedback rotating speed of the motor estimated by the frequency converter.
7. The method of claim 6, wherein the determining a speed control command based on the speed setting command and the real-time feedback rotational speed to cause the driving member to drive the motor to rotate based on the speed control command comprises:
determining a speed control instruction based on the speed setting instruction and the real-time feedback rotating speed so that the frequency converter outputs a driving frequency based on the speed control instruction to drive the motor to rotate;
correspondingly, the adjusting the speed control command based on the current running current to enable the driving part to drive the motor to rotate based on the adjusted speed control command includes:
and adjusting the speed control instruction based on the current running current so that the frequency converter outputs a driving frequency based on the adjusted speed control instruction to drive the motor to rotate.
8. A control system of a synchronous machine, characterized in that it comprises a coupling controller (1), a drive (2) and a motor (3);
the number of the driving pieces (2) and the number of the motors (3) are multiple, the driving pieces (2) are connected in a one-to-one correspondence manner, and the motors (3) are driven to rotate by the driving pieces (2);
the coupling controller (1) is electrically connected with the driving piece (2);
the coupling controller (1) is adapted to perform the method of controlling a synchronous machine according to any of claims 1-7.
9. Control system of a synchronous machine according to claim 8, characterized in that the drive (2) comprises a frequency converter (21);
the frequency converter (21) is used for outputting a driving frequency to drive the motor (3) to rotate; and/or the frequency converter (21) is used for estimating the real-time feedback rotating speed of the motor (3).
10. Control system of a synchronous machine according to claim 8 or 9, characterized in that the coupling controller (1) comprises a PLC.
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| CN202210625982.8A CN114944786A (en) | 2022-06-02 | 2022-06-02 | Control method and system of synchronous motor |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210625982.8A CN114944786A (en) | 2022-06-02 | 2022-06-02 | Control method and system of synchronous motor |
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