WO2017088141A1

WO2017088141A1 - Frequency conversion control method, apparatus and system for linear electric motor

Info

Publication number: WO2017088141A1
Application number: PCT/CN2015/095661
Authority: WO
Inventors: 谭维胜
Original assignee: 深圳市英威腾电气股份有限公司
Priority date: 2015-11-26
Filing date: 2015-11-26
Publication date: 2017-06-01
Also published as: CN107148743A; CN107148743B

Abstract

A frequency conversion control method, apparatus and system for a linear electric motor. The method comprises: determining a set frequency and a set position at various moments in a stroke of a mover of a linear electric motor; at each moment in the stroke, calculating a first frequency deviation according to a feedback position of the mover of the linear electric motor at a current moment and a current set position of the mover of the linear electric motor, acquiring a second frequency deviation at an oscillation inhibition stage, and correcting a set frequency at the current moment according to the first frequency deviation and the second frequency deviation so as to obtain a final given frequency at the current moment; calculating a target output voltage of a frequency converter at the current moment by means of the final given frequency at the current moment and a pre-set V/F control curve within a current time period; controlling the running of the linear electric motor according to the final given frequency at the current moment and the target output voltage of the frequency converter; and when a running frequency of the linear electric motor reaches a reversing frequency point, performing direct current braking within a pre-set time. The present solution can favourably realize the stable and reliable running of a linear electric motor.

Description

Linear motor control method, device and system

Technical field

The present invention relates to the field of control technologies, and in particular, to a frequency conversion control method, apparatus and system for a linear motor.

Background technique

Linear motor is a kind of transmission device that directly converts electric energy into linear motion mechanical energy without any intermediate conversion mechanism. It has obvious advantages such as simple structure, reliable operation, high transmission efficiency, low mechanical loss, low noise and good environmental adaptability. Linear motors have been widely used in industrial, civil, military and other linear motion applications. They have a wide range of applications and development prospects. They are new technologies with new principles and new theories emerging in the electrical field in the second half of the 20th century.

The application of linear motors in the field of pumping units is a new technology. The combination of linear motors and pumping pumps constitutes a linear motor submersible pump. As a pumping unit, the linear motor submersible electric pump is deeply buried underground, and the oil is directly extracted through the pipeline without the need of a sucker rod. It can fundamentally solve the problems of sucking rod wear and oil leakage which often occur in the conventional rod pumping system. At the same time, the linear motor submersible electric pump can be used as a pumping unit to save a lot of electric energy and land. The linear motor only consumes electricity when lifting, and basically does not consume electricity in the downlink, and the linear motor pumping system has only one frequency conversion control on the ground. Cabinets and distribution boxes save land much more than traditional pumping systems.

The linear motor submersible electric pump has many advantages as a pumping unit. However, on the one hand, the submersible electric pump is deeply buried in the ground, which causes the cable between the inverter and the linear motor to be long (about one thousand meters). It is easy for the inverter to control the linear motor through such a long cable. The linear motor is out of step, which leads to inaccurate linear motor travel. On the other hand, the linear motor submersible pump is inconvenient to install the linear grating sensor, so it can only be used. Open-loop control scheme, and open-loop control scheme, when the linear motor mover frequently runs up and down, there will be errors in the stroke, the error will gradually accumulate, and large deviations or even safety accidents are easy to occur. These two aspects can not achieve stable and reliable linear motors. Running. Therefore, an innovative technology is needed to realize the stable and reliable operation of the linear motor, thereby providing a guarantee for the application of the linear motor submersible electric pump.

Summary of the invention

In view of this, the present invention provides a frequency conversion control method, device and system for a linear motor, which can achieve a stable and reliable operation of the linear motor, thereby providing a guarantee for the application of the linear motor submersible electric pump.

To achieve the above object, the present invention provides the following technical solutions:

A frequency conversion control method for a linear motor, comprising:

After the linear motor is started, the first technical solution is executed cyclically;

The first technical solution includes:

Determine the running direction of the linear motor mover, the acceleration running time, the constant running time, the deceleration running time and the running speed of the linear motor during constant speed running;

The set running frequency corresponding to each moment in the linear motor mover stroke is determined by the acceleration running time, the constant running time, the decelerating running time and the running speed of the linear motor at the constant speed running, and the corresponding time is set by the linear motor mover stroke a fixed frequency, determining a set position at each moment in the linear motor mover stroke; a set position at any one of the linear motor mover strokes corresponds to a set frequency corresponding to the arbitrary one of the times;

At each moment in the linear motor mover stroke, the first frequency deviation is calculated from the feedback position of the linear motor mover at the current time and the set position of the linear motor mover at the current time, and the second frequency deviation of the oscillation suppression link is obtained. The first frequency deviation and the second frequency deviation correct a set frequency corresponding to the current time, and obtain a final given frequency corresponding to the current time;

Calculating the target output voltage of the inverter at the current moment by using the final given frequency corresponding to the current moment and the preset current period variable voltage variable frequency V/F control curve;

Controlling the linear motor operation according to the final given frequency corresponding to the current moment and the target output voltage of the inverter at the current moment;

When the running frequency of the linear motor reaches the commutation frequency point, DC braking is performed within the preset time.

Preferably, if the linear motor is operated for the first time after the stop, the length of the upward stroke of the linear motor mover is the sum of the set stroke length and the lower offset length, and the length of the stroke after the first upward running of the linear motor is the set stroke length. .

Preferably, the set running frequency corresponding to each moment in the linear motor mover stroke is determined by the accelerated running time, the constant running time, the decelerating running time, and the running speed of the linear motor during the constant speed running, including:

The linear motor mover is uniformly accelerated, and the acceleration running time of the zero motion reaches the standard of the linear motor running frequency during the constant speed operation, and the set frequency corresponding to each time in the acceleration running time period of the linear motor mover stroke is calculated. ;

The linear motor mover is evenly decelerated, and the linear motor running frequency movement is reduced to zero according to the running speed of the linear motor during the constant speed operation, and the corresponding setting at each time of the deceleration running time period of the linear motor mover stroke is calculated. frequency;

It is determined that the running speed of the linear motor during the uniform running is the set frequency corresponding to each time in the linear motor moving stroke at the constant running time period.

Preferably, the set frequency corresponding to each moment in the linear motor mover stroke determines the set position of each moment in the linear motor mover stroke, including:

The set frequency corresponding to each time in the linear motor mover stroke is integrated to obtain a set position of the corresponding time in the linear motor mover stroke.

Preferably, before calculating the first frequency deviation from the feedback position of the linear motor mover at the current time and the set position of the linear motor mover at the current time, the method further includes:

The final given frequency corresponding to the previous time is integrated to obtain the feedback position of the linear motor mover at the current time.

Preferably, the first frequency deviation is calculated by the feedback position of the linear motor mover at the current time and the set position of the linear motor mover at the current time, including:

The set position of the linear motor mover at the current time is subtracted from the feedback position of the linear motor mover at the current time, and the first frequency deviation is obtained by proportional adjustment.

Preferably, the correcting the corresponding frequency corresponding to the current time by using the first frequency deviation and the second frequency deviation to obtain a final given frequency corresponding to the current time, including:

Calculating a sum of the first frequency deviation, the second frequency deviation, and a set frequency corresponding to the current time, and obtaining a final given frequency corresponding to the current time.

Preferably, the accelerated operation phase, the constant speed operation phase and the deceleration operation phase of the linear motor mover respectively correspond to the preset variable voltage variable frequency V/F control curve.

A frequency conversion control device for a linear motor, comprising:

The first determining module is configured to determine a running direction of the linear motor mover, an acceleration running time, a constant running time, a deceleration running time, and a running speed of the linear motor during the constant speed running;

The second determining module is configured to determine the setting frequency corresponding to each moment in the linear motor mover stroke by the acceleration running time, the constant running time, the deceleration running time, and the running speed of the linear motor during the constant speed running Rate, determining a set position at each moment in the linear motor mover stroke by the set frequency corresponding to each moment in the linear motor mover stroke; setting position at any one of the linear motor mover strokes and the arbitrary Corresponding to the set frequency at a time;

The correction module is configured to calculate the first frequency deviation from the feedback position of the linear motor mover at the current time and the set position of the linear motor mover at the current moment at the moment of the linear motor mover stroke, and obtain the first shock oscillation suppression link Determining, by the first frequency deviation and the second frequency deviation, a set frequency corresponding to the current time, to obtain a final given frequency corresponding to the current time;

a first calculating module, configured to calculate a target output voltage of the inverter at a current time by using a final given frequency corresponding to the current time, and a preset current time-varying variable frequency V/F control curve;

a first control module, configured to control a linear motor operation according to a final given frequency corresponding to the current moment and a target output voltage of the inverter at the current moment;

a second control module, configured to perform DC braking within a preset time when the running frequency of the linear motor reaches the commutation frequency point;

The third control module is configured to trigger the first determining module to perform a corresponding operation when the control of the second control module is completed.

Preferably, the second determining module comprises:

The first calculating unit is configured to accelerate the operation by the linear motor mover, and the accelerated running time of the zero motion reaches the running speed of the linear motor during the uniform running, and the calculated running time period of the linear motor mover stroke is calculated. The set frequency corresponding to each moment;

The second calculating unit is configured to perform the deceleration running with the linear motor mover, and the running speed of the linear motor is reduced to zero according to the running speed of the linear motor during the constant speed operation, and the deceleration running time in the linear motor mover stroke is calculated. The set frequency corresponding to each time of the segment;

The first determining unit is configured to determine that the running speed of the linear motor during the constant speed running is a set frequency corresponding to each time in the linear motor moving stroke at the constant running time period.

The third calculating unit is configured to integrate the set frequency corresponding to each moment in the linear motor mover stroke to obtain a set position of the corresponding time in the linear motor mover stroke.

Preferably, the method further includes:

The second calculating module is configured to integrate the final given frequency corresponding to the previous moment to obtain a feedback position of the linear motor mover at the current moment.

Preferably, the correction module comprises:

The fourth calculating unit is configured to calculate the first frequency deviation from the feedback position of the linear motor mover at the current time and the set position of the linear motor mover at the current time at each moment in the linear motor mover stroke.

Preferably, the correction module comprises:

a correction unit, configured to acquire a second frequency deviation of the oscillation suppression link, and calculate a sum of the first frequency deviation, the second frequency deviation, and a set frequency corresponding to the current time, to obtain the current time corresponding The final given frequency.

Preferably, the preset variable voltage variable frequency V/F control curve adopted by the calculation module includes:

The preset variable voltage variable frequency V/F control curve corresponding to the linear motor mover in the acceleration operation phase, the constant speed operation phase and the deceleration operation phase respectively.

A frequency conversion control system for a linear motor, comprising:

a linear motor and a frequency converter for driving the linear motor;

The frequency converter includes the frequency conversion control device of the linear motor described in any one of the above.

According to the above technical solution, the present invention provides a frequency conversion control method, device and system for a linear motor as compared with the prior art. The technical solution provided by the invention adopts a combination of position control and frequency control (also can be understood as speed control) to ensure the accuracy of the actual stroke of the linear motor up and down reciprocating operation. Specifically, at each moment in the linear motor mover stroke, the first frequency deviation is calculated from the feedback position of the linear motor mover at the current time and the set position of the linear motor mover at the current time, and the second shock suppression link is obtained. Frequency deviation, the first frequency deviation and the second frequency deviation are used to correct the set frequency corresponding to the current time, and the final given frequency corresponding to the current time is obtained, so that the error occurring in the stroke is processed in time, and the current correction is timely The set frequency corresponding to the time is generated, and the final given frequency corresponding to the current time is generated, and the final given frequency corresponding to the current time is used as the current control frequency for controlling the linear motor, so that the linear motor speed changes correspondingly with the running frequency of the linear motor. Then, according to the final given frequency corresponding to the current time and the target output voltage of the inverter at the current time, the linear motor operation is controlled, the error in the stroke can be eliminated in time, the control precision is high, and in addition, the open loop control scheme is inevitable The ground will cause errors, for which the invention is operated in a linear motor When the frequency of the frequency converter point in time within a preset DC braking, so that the linear motor mover will be pulled to a location, and the load is generally fixed, and therefore, each pulled to the position of the solid Therefore, this is equivalent to performing a position correction every time the DC braking is performed within the preset time, so that the stroke error occurring in the open loop control can be effectively overcome. Therefore, the technical solution provided by the invention can realize the stable and reliable operation of the linear motor, thereby providing the guarantee for the application of the linear motor submersible electric pump.

DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is an embodiment of the present invention, and those skilled in the art can obtain other drawings according to the provided drawings without any creative work.

1 is a flowchart of a frequency conversion control method for a linear motor according to an embodiment of the present invention;

2 is a block diagram of a frequency conversion control principle of a linear motor according to an embodiment of the present invention;

3 is a control curve diagram of an operating voltage and a set frequency of a linear motor mover running up and down according to an embodiment of the present invention;

4 is a schematic diagram of a positional control of a linear motor mover position according to an embodiment of the present invention;

FIG. 5 is a structural diagram of a frequency conversion control apparatus for a linear motor according to an embodiment of the present invention; FIG.

FIG. 6 is a structural diagram of a frequency conversion control system for a linear motor according to an embodiment of the present invention.

detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

The present invention will be further described in detail with reference to the accompanying drawings and specific embodiments.

Example

1 and FIG. 2, FIG. 1 is a flowchart of a frequency conversion control method for a linear motor according to an embodiment of the present invention, and FIG. 2 is a block diagram of a frequency conversion control principle of a linear motor according to an embodiment of the present invention. As shown in Figure 1, the method includes:

The first technical solution includes:

Step S101, determining a running direction of the linear motor mover, an acceleration running time, a constant running time, a deceleration running time, and a running speed of the linear motor during the constant speed running;

Specifically, before the step S101, the acceleration running time, the constant running time, the deceleration running time, and the linear motor running frequency of the linear motor mover are acquired, and the accelerated running time and the uniform running time of the linear motor mover are acquired. The linear motor running frequency is set by the user during deceleration running time and constant speed running.

Step S102, determining, by the acceleration running time, the constant running time, the deceleration running time, and the running speed of the linear motor during the constant speed running, determining a set frequency corresponding to each moment in the linear motor mover stroke, by each moment in the linear motor mover stroke Corresponding set frequency, determining the set position of each moment in the linear motor mover stroke;

Specifically, in the step S101, the running direction of the linear motor mover corresponds to the positive and negative of the set frequency corresponding to each moment in the linear motor mover stroke: when the linear motor mover is ascending, the linear motor mover The set frequency corresponding to each time in the stroke is positive; when the linear motor mover descends, the set frequency corresponding to each moment in the linear motor mover stroke is negative.

Specifically, the set position at any one of the linear motor mover strokes corresponds to the set frequency corresponding to the arbitrary one of the times.

As shown in FIG. 2, in FIG. 2, f_set represents a set frequency corresponding to different times, and each time corresponds to a set frequency f_set.

Optionally, in the step S102, the set running frequency corresponding to each moment in the linear motor mover stroke is determined by the acceleration running time, the uniform running time, the deceleration running time, and the running speed of the linear motor during the constant speed running, including:

It is determined that the running speed of the linear motor during the constant speed operation is a uniform speed in the linear motor mover stroke The set frequency corresponding to each time of the line time period.

Optionally, in the step S102, the set frequency corresponding to each moment in the linear motor mover stroke determines the set position of each moment in the linear motor mover stroke, including:

The set frequency corresponding to each time in the linear motor mover stroke is integrated to obtain a set position of the corresponding time in the linear motor mover stroke. For example, by integrating the set frequency corresponding to the time A in the linear motor mover stroke, the set position at the time A in the linear motor mover stroke can be obtained.

As shown in FIG. 2, p_ref is calculated according to the set frequency (f_set) corresponding to different times, and the set operation position in the linear motor mover stroke at the corresponding time. 1/S indicates the point.

Step S103, at each moment in the linear motor mover stroke, the first frequency deviation is calculated from the feedback position of the linear motor mover at the current time and the set position of the linear motor mover at the current time, and the second frequency of the oscillation suppression link is obtained. Deviating, correcting the set frequency corresponding to the current time by the first frequency deviation and the second frequency deviation, to obtain a final given frequency corresponding to the current time;

Optionally, in the step S103, the first frequency deviation is calculated by the feedback position of the linear motor mover at the current time and the set position of the linear motor mover at the current time, including:

As shown in Fig. 2, p_feed indicates the position of the linear motor mover fed back at different times, which is the actual position in the linear motor mover stroke. Kp represents the proportionality factor of the proportional regulator, and delta_f1 represents the first frequency deviation. That is, the p_ref of the linear motor mover at the current time is subtracted from the p_feed of the linear motor mover at the current time of the feedback, and the delta_f1 is obtained by the proportional adjuster.

As shown in FIG. 2, delta_f2 represents the deviation frequency of the oscillation suppression link output at different times, and f_ref represents the final given frequency corresponding to different times. Abc/dq represents coordinate transformation, and SVPWM (Space Vector Pulse Width Modulation) indicates that the PWM (Pulse Width Modulation) method is spatial vector pulse width modulation, PMSM (permanent magnet synchronous motor). , permanent magnet synchronous linear motor), indicating the linear motor of the present invention, optionally, is a permanent magnet synchronous linear motor. V and θ represent voltage and angle, respectively (which can also be expressed as modulation degree M and angle θ).

Optionally, in the step S103, the passing the first frequency deviation and the second frequency The deviation corrects the set frequency corresponding to the current time, and obtains the final given frequency corresponding to the current time, including:

As shown in Fig. 2, since f_set is not the final given frequency, the deviation frequency delta_f2 from the oscillation suppression link needs to be added, but f_set is calculated in real time according to the stroke length. If the final given frequency is different from f_set, The stroke length is not accurate, that is, the position of the linear motor mover is not accurate, so a position loop is made, and the final given frequency f_ref at the previous moment is integrated as the feedback position p_feed of the current time, and the set position of the current time. P_ref is compared and a deviation frequency delta_f1 is output through the proportional regulator. f_set is added to the deviation frequency delta_f2 from the oscillation suppression link and then delta_f1 is added. This ensures that there is no error in the stroke control theory.

Step S104, calculating, by using a final given frequency corresponding to the current time, and a preset current time period V/F control (volt/frequency, variable voltage frequency conversion control) ratio, calculating a target output voltage of the frequency converter at the current time;

Specifically, the accelerated operation phase, the constant speed operation phase, and the deceleration operation phase of the linear motor mover respectively correspond to the preset V/F control curve. The final given frequency corresponding to the current time is multiplied by the preset current period V/F control curve, and the target output voltage of the inverter at the current time can be calculated.

Please refer to FIG. 3. FIG. 3 is a control curve diagram of an operating voltage and a set frequency of a linear motor mover when it is operated up and down.

Specifically, one stroke of the linear motor mover is an upstroke or a downstroke. As shown in Fig. 3, the ordinate U represents the actual running voltage of the linear motor, the operating voltage curve (the thick solid line in the figure) is the voltage curve actually controlling the operation of the linear motor, and the ordinate f represents the calculated in the step S102. The set frequency corresponding to each time, the set frequency curve (the thin solid line in the figure) is the curve of the set frequency corresponding to each time calculated by the user in the step S102, and the abscissa t represents time, and the down time is set. The fixed frequency is below the horizontal axis, indicating that the linear motor has changed direction. Although the actual operating voltage of the linear motor does not directly correspond to the set frequency, there is a direct and certain correspondence between the actual operating voltage of the linear motor and the final given frequency, and the final given frequency is determined by the error of the set frequency. The value of the error is relatively small with respect to the set frequency itself. Therefore, by the control curve of the operating voltage and the set frequency in FIG. 3, it is also possible to determine each of the preset specific strokes of the present invention. The size of the V/F control curve during the sport period. As shown in FIG. 3, the V/F curve of the linear motor mover upstroke is different from the V/F curve of the downstroke, that is, the V/F curve of the upstroke and the V/F curve of the downstroke can be respectively set. In addition, it should be noted that, in the figure, the zero-speed holding phase indicates a phase in which the DC braking is performed within a preset time when the operating frequency of the linear motor reaches the commutation frequency point.

Step S105, controlling the linear motor operation according to the final given frequency corresponding to the current time and the target output voltage of the inverter at the current time;

Step S106, when the running frequency of the linear motor reaches the commutation frequency point, the DC braking is performed within a preset time;

Specifically, when the running frequency of the linear motor reaches the commutation frequency point, the linear motor mover reaches the critical position of the upper end or the lower end. At this time, the linear motor mover speed is zero, as shown in FIG. 3, at this time, the linear electric current The maneuver is in the zero-speed hold phase and faces the direction of switching. At this time, the DC braking is performed within the preset time, so that the linear motor mover is pulled to a certain position, and the load is generally fixed, so that the position to be pulled each time is fixed, which is equivalent to A position correction is performed each time DC braking is performed within a preset time, thereby effectively overcoming the stroke error occurring in the open loop control.

The frequency conversion control method of the linear motor provided by the invention adopts a combination of position control and frequency control (also can be understood as speed control) to ensure the accuracy of the actual stroke of the linear motor up and down reciprocating operation. Specifically, at each moment in the linear motor mover stroke, the first frequency deviation is calculated from the feedback position of the linear motor mover at the current time and the set position of the linear motor mover at the current time, and the second shock suppression link is obtained. Frequency deviation, the first frequency deviation and the second frequency deviation are used to correct the set frequency corresponding to the current time, and the final given frequency corresponding to the current time is obtained, so that the error occurring in the stroke is processed in time, and the current correction is timely The set frequency corresponding to the time is generated, and the final given frequency corresponding to the current time is generated, and the final given frequency corresponding to the current time is used as the current control frequency for controlling the linear motor, so that the linear motor speed changes correspondingly with the running frequency of the linear motor. Then, according to the final given frequency corresponding to the current time and the target output voltage of the inverter at the current time, the linear motor operation is controlled, the error in the stroke can be eliminated in time, the control precision is high, and in addition, the open loop control scheme is inevitable The ground will cause errors, for which the invention is operated in a linear motor When the frequency reaches the commutation frequency point, DC braking is performed within the preset time, so that the linear motor mover is pulled to a certain position, and the load is generally fixed, so the position to be pulled each time is fixed. This is equivalent to performing a position correction every time the DC braking is performed within the preset time. Effectively overcome the travel error that occurs in open loop control. Therefore, the technical solution provided by the invention can realize the stable and reliable operation of the linear motor, thereby providing the guarantee for the application of the linear motor submersible electric pump.

It should be noted that, before the step S103, the work to be prepared further includes:

In another embodiment of the present disclosure, if the linear motor is operated for the first time after the shutdown, the length of the upward stroke of the linear motor mover is the sum of the set stroke length and the lower offset length, and the linear motor after the first upward running The stroke, the length of which is the set stroke length.

Please refer to FIG. 4. FIG. 4 is a schematic diagram of a positional control of a linear motor mover position according to an embodiment of the present invention. As shown in FIG. 4, the linear motor stator 41 and the linear motor mover 42, the line segment AB is the linear motor mover operable range, and the line segment CD is the running length of the linear motor mover for the first upward running (ie, the stroke length of the first upward running). The line segment EF is the running length of the normal reciprocating (up and down) operation of the linear motor after the first upward running (ie, the running length of the normal running, that is, the set stroke length), and GH is the lower offset length. In this way, the position offset (ie GH) is left at the lower end, and the first upward run after the stop, the running length of the linear motor mover is longer than the normal up and down running, that is, the bottom dead center of the linear motor during normal reciprocating operation. It is higher than the initial position of the first upward running, which makes the bottom dead center of the normal operation of the linear motor and the bottom of the linear motor have a certain space, which can ensure that the linear motor does not collide.

In order to more fully explain the technical solution provided by the present invention, corresponding to the frequency conversion control method of the linear motor provided by the embodiment of the present invention, the present invention also discloses a frequency conversion control device for a linear motor.

Please refer to FIG. 5. FIG. 5 is a structural diagram of a frequency conversion control apparatus for a linear motor according to an embodiment of the present invention. As shown in Figure 5, the device includes:

The first determining module 501 is configured to determine a running direction of the linear motor mover, an acceleration running time, a constant running time, a deceleration running time, and a running speed of the linear motor during the constant speed running;

The second determining module 502 is configured to determine, according to the acceleration running time, the constant running time, the deceleration running time, and the running speed of the linear motor during the constant speed running, the corresponding setting of each moment in the linear motor mover stroke a fixed frequency, a set frequency corresponding to each moment in the linear motor mover stroke, determining a set position at each moment in the linear motor mover stroke; a set position at any one of the linear motor mover strokes and the stated Corresponding to the set frequency at any one time;

The correction module 503 is configured to calculate the first frequency deviation from the feedback position of the linear motor mover at the current time and the set position of the linear motor mover at the current time at each moment of the linear motor mover stroke, and obtain the oscillation suppression link. a second frequency deviation, the first frequency deviation and the second frequency deviation are used to correct a set frequency corresponding to the current time, to obtain a final given frequency corresponding to the current time;

The first calculating module 504 is configured to calculate a target output voltage of the frequency converter at a current time by using a final given frequency corresponding to the current time, and a preset current time-varying variable frequency V/F control curve;

The first control module 505 is configured to control the linear motor operation according to the final given frequency corresponding to the current moment and the target output voltage of the inverter at the current moment;

The second control module 506 is configured to perform DC braking within a preset time when the running frequency of the linear motor reaches the commutation frequency point;

The third control module 507 is configured to trigger the first determining module to perform a corresponding operation when the control of the second control module is completed.

Specifically, the second determining module 502 includes:

Specifically, the modification module 503 includes:

a fourth calculating unit, configured to calculate a first frequency deviation from a feedback position of the linear motor mover at the current time and a set position of the linear motor mover at the current time at each moment in the linear motor mover stroke;

Specifically, the preset V/F control curve adopted by the first calculating module 504 includes:

The preset V/F control curve of the linear motor mover in the acceleration operation phase, the constant speed operation phase and the deceleration operation phase respectively.

Specifically, the inverter control device for the linear motor provided by the embodiment of the present invention further includes:

In order to more fully explain the technical solution provided by the present invention, the present invention also discloses a frequency conversion control system for a linear motor corresponding to the frequency conversion control method of the linear motor provided by the embodiment of the present invention.

Please refer to FIG. 6. FIG. 6 is a structural diagram of a frequency conversion control system for a linear motor according to an embodiment of the present invention. As shown in Figure 6, the system includes:

a linear motor 601 and a frequency converter 602 for driving the linear motor 601;

The frequency converter 601 includes the frequency conversion control device of the linear motor provided by the embodiment of the present invention.

Specifically, the inverter 601 is internally provided with a control circuit, and the control circuit includes a control chip, and the control chip integrates the functions of the linear motor frequency conversion control device provided by the embodiment of the present invention, that is, the implementation of the present invention described above. The functions of each module of the linear motor frequency conversion control device and the internal units of each module are implemented based on the control chip.

According to the above technical solution, the present invention provides a frequency conversion control method, device and system for a linear motor as compared with the prior art. The technical solution provided by the invention adopts a combination of position control and frequency control (also can be understood as speed control) to ensure the accuracy of the actual stroke of the linear motor up and down reciprocating operation. Specifically, at each moment in the linear motor mover stroke, the first frequency deviation is calculated from the feedback position of the linear motor mover at the current time and the set position of the linear motor mover at the current time, and the second shock suppression link is obtained. Frequency deviation, the first frequency deviation and the second frequency deviation are used to correct the set frequency corresponding to the current time, and the final given frequency corresponding to the current time is obtained, so that the error occurring in the stroke is processed in time, and the current correction is timely Time setting frequency Rate, generating the final given frequency corresponding to the current time, using the final given frequency corresponding to the current time as the current control frequency for controlling the linear motor, so that the linear motor speed changes correspondingly with the linear motor operating frequency, and then, according to the The final given frequency corresponding to the current time and the target output voltage of the inverter at the current time control the linear motor operation, which can eliminate the error in the stroke in time, and the control precision is high. In addition, since the open-loop control scheme inevitably causes errors, Therefore, the present invention performs DC braking within a preset time when the running frequency of the linear motor reaches the commutation frequency point, so that the linear motor mover is pulled to a certain position, and the load is generally fixed, so Each time the position to be pulled is fixed, this is equivalent to performing a position correction every time the DC braking is performed within the preset time, so that the stroke error occurring in the open loop control can be effectively overcome. Therefore, the technical solution provided by the invention can realize the stable and reliable operation of the linear motor, thereby providing the guarantee for the application of the linear motor submersible electric pump.

Specifically, the linear motor submersible electric pump is deeply buried underground, and the cable length is more than one thousand meters. In the case where the linear grating sensor is not installed (due to the limitation of the linear motor submersible electric pump, the linear grating sensor cannot be installed), only The open-loop control scheme can be adopted, and the open-loop control scheme, when the linear motor mover frequently runs up and down, there will be errors in the stroke, the error gradually accumulates, and large deviations or even safety accidents (such as linear motor movers up and down collisions) are prone to occur. Therefore, it is very difficult to realize the reciprocating and reliable operation of the linear motor submersible electric pump. The technical solution provided by the present invention adopts a combination of position control and frequency control (also can be understood as speed control) to improve the accuracy of the actual stroke of the linear motor up and down reciprocating operation, and increase the lower offset length to improve the system. The reliability of operation, but due to the linear motor submersible electric pump itself can not install the linear grating sensor, can only use the open loop control scheme, open loop control scheme, the running stroke is inevitable there is a certain error, in order to solve this problem The invention creatively provides an effective solution, that is, when the running frequency of the linear motor reaches the commutation frequency point (ie, the zero speed holding phase of the motor), the DC braking is performed within a preset time, such that the electric The motorized man will be pulled to a certain position, and the load is basically fixed, so the position that is pulled to each time is basically fixed, which is equivalent to performing a position correction every time the zero speed is maintained, thereby being effective. Eliminate the travel error that occurs with open loop control. That is to say, the technical solution provided by the present invention is based on the prior art that the linear motor submersible electric pump cannot install the linear grating speed scale due to its own limitation, so it can only adopt the position control and frequency control under the background of open loop control. Set the lower offset length and the zero speed of the motor to maintain the DC braking, and finally realize the stable and reliable operation of the linear motor. Overcoming the inaccuracy of the linear motor mover stroke of the linear motor submersible electric pump as the pumping unit in the prior art and the linear motor mover caused by the open loop control scheme are prone to large deviation or even safety accident.

Because the linear motor submersible electric pump is buried underground as a pumping unit, the oil is directly pumped out through the pipeline without the need of a sucker rod, which can fundamentally solve the problems of sucking rod wear and oil leakage that often occur in the traditional rod pumping system. At the same time, the use of linear motor submersible electric pump as a pumping unit can also save a lot of electric energy and land. Therefore, the linear motor submersible electric pump as a pumping unit has obvious advantages over the conventional rod pumping system. At the same time, the technical solution provided by the present invention can overcome the defects of the linear motor submersible electric pump in the prior art and ensure stable and reliable operation. Therefore, it can be understood that the technical solution provided by the present invention can be powerful. Promote the promotion and application of linear motor submersible electric pump in the field of pumping unit.

Finally, it should also be noted that in this context, relational terms such as first and second are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply these entities. There is any such actual relationship or order between operations. Furthermore, the term "comprises" or "comprises" or "comprises" or any other variations thereof is intended to encompass a non-exclusive inclusion, such that a process, method, article, or device that comprises a plurality of elements includes not only those elements but also Other elements, or elements that are inherent to such a process, method, item, or device. An element that is defined by the phrase "comprising a ..." does not exclude the presence of additional equivalent elements in the process, method, item, or device that comprises the element.

The various embodiments in the present specification are described in a progressive manner, and each embodiment focuses on differences from other embodiments, and the same similar parts between the various embodiments may be referred to each other. For the variable frequency control device and system of the linear motor disclosed in the embodiment, since it corresponds to the frequency conversion control method of the linear motor disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the description of the method.

The steps of a method or algorithm described in connection with the embodiments disclosed herein can be implemented in a combination of both hardware and a software module executed by a processor. The software module can be placed in a storage medium of the processor.

The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be practiced without departing from the spirit or scope of the invention. Implemented in other embodiments. Therefore, the present invention is not to be limited to the embodiments shown herein, but the scope of the invention is to be accorded

Claims

A frequency conversion control method for a linear motor, characterized in that it comprises:

After the linear motor is started, the first technical solution is executed cyclically;

The first technical solution includes:

Determine the running direction of the linear motor mover, the acceleration running time, the constant running time, the deceleration running time and the running speed of the linear motor during constant speed running;

The set running frequency corresponding to each moment in the linear motor mover stroke is determined by the acceleration running time, the constant running time, the decelerating running time and the running speed of the linear motor at the constant speed running, and the corresponding time is set by the linear motor mover stroke a fixed frequency, determining a set position at each moment in the linear motor mover stroke; a set position at any one of the linear motor mover strokes corresponds to a set frequency corresponding to the arbitrary one of the times;

At each moment in the linear motor mover stroke, the first frequency deviation is calculated from the feedback position of the linear motor mover at the current time and the set position of the linear motor mover at the current time, and the second frequency deviation of the oscillation suppression link is obtained. The first frequency deviation and the second frequency deviation correct a set frequency corresponding to the current time, and obtain a final given frequency corresponding to the current time;

Calculating the target output voltage of the inverter at the current moment by using the final given frequency corresponding to the current moment and the preset current period variable voltage variable frequency V/F control curve;

Controlling the linear motor operation according to the final given frequency corresponding to the current moment and the target output voltage of the inverter at the current moment;

When the running frequency of the linear motor reaches the commutation frequency point, DC braking is performed within the preset time.
The method according to claim 1, wherein if the linear motor is operated for the first time after the stop, the length of the upward stroke of the linear motor mover is the sum of the set stroke length and the lower offset length, and the linear motor runs for the first time. The length of the subsequent stroke is the set stroke length.
The method according to claim 1, wherein the set operating frequency corresponding to each moment in the linear motor mover stroke is determined by the acceleration running time, the constant running time, the decelerating running time, and the running speed of the linear motor during the constant speed running, include:

The linear motor mover accelerates evenly, and the acceleration running time of the zero motion reaches the running speed of the linear motor during the uniform speed operation, and the accelerated running time in the linear motor mover stroke is calculated. The set frequency corresponding to each time of the segment;

The linear motor mover is evenly decelerated, and the linear motor running frequency movement is reduced to zero according to the running speed of the linear motor during the constant speed operation, and the corresponding setting at each time of the deceleration running time period of the linear motor mover stroke is calculated. frequency;

It is determined that the running speed of the linear motor during the uniform running is the set frequency corresponding to each time in the linear motor moving stroke at the constant running time period.
The method according to claim 1, wherein the set position corresponding to each moment in the linear motor mover stroke determines a set position at each moment in the linear motor mover stroke, including:

The set frequency corresponding to each time in the linear motor mover stroke is integrated to obtain a set position of the corresponding time in the linear motor mover stroke.
The method according to claim 1, wherein at each moment in the linear motor mover stroke, the feedback position of the linear motor mover at the current time and the set position of the linear motor mover at the current time are calculated. Before a frequency deviation, it also includes:

The final given frequency corresponding to the previous time is integrated to obtain the feedback position of the linear motor mover at the current time.
The method according to claim 5, wherein the calculating the first frequency deviation by the feedback position of the linear motor mover at the current time and the set position of the linear motor mover at the current time comprises:

The set position of the linear motor mover at the current time is subtracted from the feedback position of the linear motor mover at the current time, and the first frequency deviation is obtained by proportional adjustment.
The method according to claim 1, wherein the correcting the set frequency corresponding to the current time by the first frequency deviation and the second frequency deviation to obtain a final given frequency corresponding to the current time comprises:

Calculating a sum of the first frequency deviation, the second frequency deviation, and a set frequency corresponding to the current time, and obtaining a final given frequency corresponding to the current time.
The method according to claim 1, wherein the acceleration running phase, the constant speed running phase and the deceleration running phase of the linear motor mover respectively correspond to the preset variable voltage variable frequency V/F control curve.
A frequency conversion control device for a linear motor, comprising:

The first determining module is configured to determine a running direction of the linear motor mover, an acceleration running time, a constant running time, a deceleration running time, and a running speed of the linear motor during the constant speed running;

a second determining module, configured to determine a set frequency corresponding to each moment in the linear motor mover stroke by the acceleration running time, the constant running time, the deceleration running time, and the linear motor running frequency at the constant speed running, by the linear motor mover The set frequency corresponding to each time in the stroke determines the set position at each moment of the linear motor mover stroke; the set position at any one of the linear motor mover strokes corresponds to the set frequency corresponding to the arbitrary one of the times ;

The correction module is configured to calculate the first frequency deviation from the feedback position of the linear motor mover at the current time and the set position of the linear motor mover at the current moment at the moment of the linear motor mover stroke, and obtain the first shock oscillation suppression link Determining, by the first frequency deviation and the second frequency deviation, a set frequency corresponding to the current time, to obtain a final given frequency corresponding to the current time;

a first calculating module, configured to calculate a target output voltage of the inverter at a current time by using a final given frequency corresponding to the current time, and a preset current time-varying variable frequency V/F control curve;

a first control module, configured to control a linear motor operation according to a final given frequency corresponding to the current moment and a target output voltage of the inverter at the current moment;

a second control module, configured to perform DC braking within a preset time when the running frequency of the linear motor reaches the commutation frequency point;

The third control module is configured to trigger the first determining module to perform a corresponding operation when the control of the second control module is completed.
The apparatus according to claim 9, wherein the second determining module comprises:

The first calculating unit is configured to accelerate the operation by the linear motor mover, and the accelerated running time of the zero motion reaches the running speed of the linear motor during the uniform running, and the calculated running time period of the linear motor mover stroke is calculated. The set frequency corresponding to each moment;

The second calculating unit is configured to perform the deceleration running with the linear motor mover, and the running speed of the linear motor is reduced to zero according to the running speed of the linear motor during the constant speed operation, and the deceleration running time in the linear motor mover stroke is calculated. The set frequency corresponding to each time of the segment;

a first determining unit, configured to determine that the running speed of the linear motor during the constant speed operation is a set frequency corresponding to each time in the constant speed running time period of the linear motor moving stroke;

a third calculating unit, configured to set a corresponding frequency corresponding to each moment in the linear motor mover stroke The integral is obtained, and the set position of the corresponding time in the linear motor mover stroke is obtained.
The device according to claim 9, further comprising:

The second calculating module is configured to integrate the final given frequency corresponding to the previous moment to obtain a feedback position of the linear motor mover at the current moment.
The device according to claim 11, wherein the correction module comprises:

The fourth calculating unit is configured to calculate the first frequency deviation from the feedback position of the linear motor mover at the current time and the set position of the linear motor mover at the current time at each moment in the linear motor mover stroke.
The apparatus according to claim 9, wherein the correction module comprises:

a correction unit, configured to acquire a second frequency deviation of the oscillation suppression link, and calculate a sum of the first frequency deviation, the second frequency deviation, and a set frequency corresponding to the current time, to obtain the current time corresponding The final given frequency.
The apparatus according to claim 9, wherein the preset variable voltage variable frequency V/F control curve adopted by the calculation module comprises:

The preset variable voltage variable frequency V/F control curve corresponding to the linear motor mover in the acceleration operation phase, the constant speed operation phase and the deceleration operation phase respectively.
A frequency conversion control system for a linear motor, comprising:

a linear motor and a frequency converter for driving the linear motor;

The frequency converter includes the inverter control device for the linear motor according to any one of claims 9 to 14.