CN101719751A - Method and device for soft stop control for pump loaded motor - Google Patents
Method and device for soft stop control for pump loaded motor Download PDFInfo
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- CN101719751A CN101719751A CN201010101984A CN201010101984A CN101719751A CN 101719751 A CN101719751 A CN 101719751A CN 201010101984 A CN201010101984 A CN 201010101984A CN 201010101984 A CN201010101984 A CN 201010101984A CN 101719751 A CN101719751 A CN 101719751A
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Abstract
The invention discloses a method and a device for soft stop control for a pump loaded motor. A soft stop control scheme of active power closed-loop control can be designed by measuring the active power of the motor in real time, the constant power adjustment can be performed by adopting the adjustment for the active power, the predetermined active power produced by a soft stop control rule function is compared with the real-time active power to generate a power error signal, a phase-shifting angle of a main circuit is changed through the error signal so that the active power of the motor is changed according to the set soft stop control rule, and finally the motor is steadily stopped. The method and the device solve the problem that the pump loaded surge is easy to cause during pump loaded soft stop.
Description
Technical field
The present invention relates to a kind of soft stop control method and device of motor, the particularly soft stop control method and the device of load of the pumps asynchronous machine belong to the technical field of motor control assembly.
Background technology
Motor is extensive use of in industrial circles such as metallurgy, chemical industry, building, mine, and wherein, the most commonly used is AC induction motor, and this motor is that back-emf is main load.When electric motor starting, back-emf can increase and becomes big gradually along with the rotating speed of rotor, so the impulse current during electric motor starting is very big, therefore can load be worked the mischief, and the harm to load of the pumps is bigger especially.Because the load torque characteristic of pump type systematic load and the torque characteristics of asynchronous machine do not match, the motor across-the-line starting and the commentaries on classics that causes of stopping cause liquid flow impact apart from sudden change, make pumping system produce surge and noise, when rotating speed of motor is lower than its critical whirling speed, change apart from load for perseverance, at this moment the stall phenomenon just takes place, and when serious pipeline and support of pipelines is rocked, even makes pipeline and valve break or rupture.Therefore, people are seeking surge and the noise that the whole bag of tricks reduces or eliminate pumping system always.
In order to solve the problems of the technologies described above; common meeting Series Frequency Conversion device or soft starter between power supply and asynchronous machine; so that electric motor starting or can obtain perfect performance when stopping, but the costing dearly of frequency converter, and lower for its cost performance of the occasion that does not need Flow-rate adjustment.Though and soft starter performance can improve Pumping System During Starting Period the time, reduce surge and noise, but the performance when the soft mode of stopping of linear ramp step-down commonly used can not effectively be improved the pumping system parking usually causes motor stopped process medium speed instability, makes pumping system produce surge phenomenon.This is because the soft starter of asynchronous machine adopts linear ramp step-down mode to carry out the soft control that stops usually.This control mode is easy to cause the surge of pumping system, and this is changeed not match apart from characteristic and pumping system load torque characteristic by asynchronous machine and causes.As everyone knows, the flow of pumping system and rotating speed have following fundamental relation formula:
Q-----------------liquid stream flow in the formula
The rotating speed of N-----------------pump
The variation of POF and revolution speed be varied to direct ratio.Pumping system load torque, flow stream pressure and rotating speed have following fundamental relation formula:
T----------------load torque in the formula
The P----------------flow stream pressure
The variation and the flow stream pressure that are the load torque of pumping system are varied to direct ratio, with square being directly proportional that revolution speed changes.Therefore, the minor variations of revolution speed will cause the variation by a relatively large margin of load torque and flow stream pressure.
The load of the pumps of Induction Motor-Driven is in the soft stopping time of linear ramp step-down, the bad stability of system, and the soft control mode of stopping of linear ramp step-down is open loop control, therefore can not suppress the generation of pumping system vibration.
In order to solve the oscillation problem in soft stopping time of pumping system, adopt closed-loop control to control the shutdown of asynchronous machine at soft starter.Can solve oscillation problem though introduce speed closed loop control, need extra speed measuring device is installed, this is normally infeasible to load of the pumps.
Recently, Chinese patent literature discloses a kind of control method and equipment of motor, the application number of this patent documentation is " 200410052898.3 ", patent name is " control electric machine soft starting and the soft method and apparatus that stops ", wherein, the soft stop control method of motor that discloses comprises: 1, enter and softly output to motor again after stopping after the process operating voltage is linked into main circuit; 2, control the angle of flow of the thyristor of described main circuit according to predetermined electric moter voltage decline curve; 3, by current transformer sampled voltage and current signal; 4, relatively three-phase triggers difference between the voltage and current signal of the voltage and current signal of feedback and described predetermined function; 5, according to the angle of flow of the described described thyristor of discrepancy adjustment that records, so that the predetermined voltage of the voltage of described motor trend reduces to zero until the voltage of described motor, soft process of stopping finishes.This control method since be with the real-time current of motor and voltage directly and predetermined current and voltage ratio; the voltage of motor and electric current are for the rotating speed of pump load corresponding relation not; therefore, control and inaccuracy to motor is shut down can cause the vibration of load of the pumps equally.
Summary of the invention
The object of the present invention is to provide a kind of soft stop control method and device of pump loaded motor; this invention is controlled by the phase shifting angle to main circuit; motor is descended according to predetermined ideal curve, thereby solved the problem that load of the pumps in the motor stopping process causes the load of the pumps surge easily.
In order to solve the problems of the technologies described above, the soft stop control method of a kind of pump loaded motor of the present invention comprises the steps:
1.1, enter and softly output to motor again after stopping after the process operating voltage is linked into main electrical equipment;
1.2, control the angle of flow of the thyristor of described main circuit according to predetermined motor active power decline curve;
1.3, gather voltage and electric current that described main circuit outputs to motor;
1.4, voltage and electric current are pressed
Or
Set up Mathematical Modeling, calculate the real-time active power of motor;
1.5, relatively gather difference between the predetermined active power of real-time active power that the voltage and current signal draws and described predetermined electric moter voltage decline harmonic curve;
1.6, according to the angle of flow of the described thyristor of discrepancy adjustment between the described active power so that the predetermined voltage of the voltage of described motor trend reduces to zero until the voltage of described motor, soft process of stopping finishes.
A kind of soft stop control method of pump loaded motor wherein, may further comprise the steps:
1.1, enter and softly output to motor again after stopping after the process operating voltage is linked into main circuit;
1.2, control the angle of flow of the thyristor of described main circuit according to predetermined electric moter voltage decline curve;
1.3, gather voltage and electric current that described main circuit outputs to motor;
1.4, voltage and electric current are pressed
Or
Set up Mathematical Modeling, calculate the real-time active power of motor;
1.5, the predetermined active power of gathering predetermined electric moter voltage decline curve;
1.6, relatively gather difference between the predetermined active power that real-time active power that the voltage and current signal draws and described predetermined electric moter voltage decline harmonic curve draw;
1.7, gather the electric current that described main circuit outputs to motor;
1.8, will be relatively the electric current exported of scheduled current and the main circuit of back output compare, draw two differences between all, the angle of flow according to the described thyristor of discrepancy adjustment between the described electric current, so that the predetermined voltage of the voltage of described motor trend, reduce to zero until the voltage of described motor, soft process of stopping finishes.
The invention provides the soft stop device of realizing said method, this device comprises the main circuit that inserts between power supply and the motor, output control device, described output control device comprises real-time active power generation module, specified active power generation module, power comparison module, power conditioning module, described real-time active power generation module input links to each other with the output of main circuit, and output links to each other with the input of described power comparison module; The input of described power comparison module also links to each other with described specified active power generation module output, the output of described power comparison module links to each other with the input of described power conditioning module, and the output of described power conditioning module links to each other with described main circuit control end.
Above-mentioned a kind of motor soft starter of controlling load of the pumps, wherein, described realtime power generation module comprises voltage detection module, current detection module, phase shifting angle detection module, computing module; The input of described voltage, electric current and phase shifting angle detection module described main circuit output respectively links to each other, and output links to each other with the input of described computing module respectively.
Above-mentioned a kind of motor soft starter of controlling load of the pumps wherein, also comprises current control system, and described current control system is connected between described main circuit and the described output control device; Described current control system comprises current comparing module, current regulating module, the input of described current comparing module links to each other with the output of described power conditioning module and the output of described main circuit respectively, and the output of described current comparing module links to each other with the input of described current regulating module; The output of described current regulating module links to each other with the control end of described main circuit.
The present invention has following beneficial effect:
1, because the active power of motor is carried out closed-loop control, motor is soft to stop in the process, after measuring motor active power in real time, the active power that produces with specified active power generation module compares, and produce a power error signal, power error signal is delivered to power governor, power governor changes the phase shifting angle of main circuit according to error signal, motor active power is changed by setting the soft control law of stopping, motor is descended according to desirable curve, finally make motor out of service stably, thereby solved the soft stopping time of load of the pumps, cause the problem of load of the pumps surge easily.
2, owing to the present invention includes voltage detection module, current detection module, phase shifting angle detection module, computing module, if the electric voltage exception situation of overload overvoltage or power supply phase shortage appears in motor, can in time detect, thereby improve the fail safe in soft stopping time of motor.
3, because the present invention has adopted current control system, can avoid when load is big, the current peak of motor reaches the several times of rated current, thereby has further improved the fail safe in soft stopping time of motor.
Adopted method of the present invention; the phase shifting angle that active power by adjusting the main circuit input or electric current are regulated; thereby the voltage of motor is descended according to predetermined curve chart; make the decline of motor more steady; thereby improved the stationarity in soft stopping time of motor, solved the problem that load of the pumps in the motor stopping process causes the load of the pumps surge easily.
Description of drawings
Fig. 1 is the workflow diagram of the embodiment of the invention one
Fig. 2 is the workflow diagram of the embodiment of the invention two
Fig. 3 is a structure principle chart of the present invention
Embodiment
The invention will be further described below in conjunction with accompanying drawing.
Embodiment one: in order to solve the problems of the technologies described above, the soft stop control method of a kind of pump loaded motor of the present invention comprises the steps:
1.1, enter and softly output to motor again after stopping after the process operating voltage is linked into main circuit;
1.2, control the angle of flow of the thyristor of described main circuit according to predetermined electric moter voltage decline curve;
1.3, gather voltage and electric current that described main circuit outputs to motor;
1.4, voltage and electric current are pressed
Or
Set up Mathematical Modeling, calculate the real-time active power of motor; For the single phase alternating current (A.C.) asynchronous machine, its active power mean value at the one-period internal consumption may be defined as:
In the formula: the active power mean value in the P-----one-period
The cycle of T-----AC power
U (t)---instantaneous voltage
I (t)---current instantaneous value
Therefore, by detecting the voltage and current of load, just can calculate the active power of load.
Adopt when digital control, active power can be calculated by formula (8):
In the formula:
Interior sampling number of AC power cycle of N-------, sample frequency should be much larger than supply frequency
The n time voltage sample value of Un-------
In-------n primary current sampled value
NO------ought last time sample
Because threephase asynchronous machine is three phase symmetry load, its total active power consumption is one to go up 3 times of active power mutually, so as long as the phase voltage and the phase current of detection one phase just can calculate total active power consumption.
1.5, relatively gather difference between the predetermined active power that real-time active power that the voltage and current signal draws and described predetermined electric moter voltage decline harmonic curve draw;
1.6, according to the angle of flow of the described thyristor of discrepancy adjustment between the described active power so that the predetermined voltage of the voltage of described motor trend reduces to zero until the voltage of described motor, soft process of stopping finishes.
Embodiment two: in the process that motor speed reduces, because the inherent characteristic of asynchronous machine, when load was big, the current peak of motor can reach the several times of rated current.This situation does not wish to take place.Therefore on the basis of active power closed-loop control, also need to add current limliting, to guarantee softly to stop that current of electric can not surpass the current value that allows in the process.
For increasing Current limited Control, to compare between real-time active power and the described predetermined active power, the electric current that obtains difference between the two is as scheduled current, relatively produce a current error signal in the back with the current of electric that obtains of sampling, current PI D adjuster with in this current error signal as importing the phase shifting angle of controlling main circuit.
A kind of soft stop control method of pump loaded motor wherein, may further comprise the steps:
1.1, enter and softly output to motor again after stopping after the process operating voltage is linked into main circuit;
1.2, control the angle of flow of the thyristor of described main circuit according to predetermined electric moter voltage decline curve;
1.3, gather voltage and electric current that described main circuit outputs to motor;
1.4, voltage and electric current are pressed
Or
Set up Mathematical Modeling, calculate the real-time active power of motor;
1.5, relatively gather difference between the predetermined active power that real-time active power that the voltage and current signal draws and described predetermined electric moter voltage decline harmonic curve draw;
1.6, gather the relatively scheduled current signal of back output;
1.7, gather the electric current that described main circuit outputs to motor;
1.8, will be relatively the electric current exported of scheduled current and the main circuit of back output compare, draw difference between the two, the angle of flow according to the described thyristor of discrepancy adjustment between the described electric current, so that the predetermined voltage of the voltage of described motor trend, reduce to zero until the voltage of described motor, soft process of stopping finishes.
The invention provides the soft stop device of realizing said method, comprise the main circuit 1 that inserts between power supply and the motor, output control device 2, described output control device 2 comprises real-time active power generation module 21, specified active power generation module 22, power comparison module 23, power conditioning module 24, described real-time active power generation module 21 inputs link to each other with the output of main circuit 1, and output links to each other with the input of described power comparison module 23; The input of described power comparison module 23 also links to each other with described specified active power generation module 22 outputs, the output of described power comparison module 23 links to each other with the input of described power conditioning module 24, and the output of described power conditioning module 24 links to each other with described main circuit 1 control end.Because the active power of motor is carried out closed-loop control, motor is soft to stop in the process, after obtaining motor active power in real time by real-time active power generation module 21, the active power that produces with specified active power generation module 22 compares, and produce a power error signal, power error signal is delivered to power governor, power governor changes the phase shifting angle of main circuit according to error signal, motor active power is changed by setting the soft control law of stopping, motor is descended according to desirable curve, finally make motor out of service stably, thereby solved the soft stopping time of load of the pumps, cause the problem of load of the pumps surge easily.
In order to improve the fail safe of motor, described realtime power generation module 21 comprises voltage detection module 211, current detection module 212, phase shifting angle detection module 213, computing module 214; Described voltage; electric current and phase shifting angle detection module 211; 212; 213 input described main circuit 1 output respectively links to each other; output links to each other with the input of described computing module 214 respectively; during work; pass through electric current; voltage and phase shifting angle detection module detect the real-time electric current of motor; voltage and phase shifting angle; again by computing module calculate motor real-time active power; compare the error of real-time active power and specified active power by the power comparison module; by the power comparison module phase shifting angle of main circuit is adjusted again, motor is steadily shut down according to the curve that sets.Owing to the present invention includes 211 of voltage detecting moulds, current detection module 212, phase shifting angle detection module 213, computing module 214, if the electric voltage exception situation of overload overvoltage or power supply phase shortage appears in motor, can in time detect, thereby improve the fail safe in soft stopping time of motor.
When big, the peak current of motor is excessive, also current control system 3 can be set for fear of load, and described current control system 3 is connected between described main circuit 1 and the described output control device 2; Described current control system 3 comprises current comparing module 31, current regulating module 32, the input of described current comparing module 31 links to each other with the output of described power conditioning module 32 and the output of described main circuit 1 respectively, and the output of described current comparing module 31 links to each other with the input of described current regulating module 32; The output of described current regulating module 32 links to each other with the control end of described main circuit 1.Because the present invention has adopted current control system, can avoid when load is big, the current peak of motor reaches the several times of rated current, thereby has further improved the fail safe in soft stopping time of motor.
Result of the test: the soft motor current waveform of stopping process of motor, wherein, be made as between the soft stopping time 30 seconds, maximum soft power failure stream is set at 2 times of rated current.Originally soft stopping paying out given birth to vibration under linear ramp step-down open loop control; can shut down stably under the control of active power/current double closed-loop, current waveform shows and softly stops that current of electric changes steadily in the process that motor torque changes steadily; motor speed steadily descends, and does not vibrate.The time of shutting down can be set arbitrarily between 0～120 second on request.In the stopping process, current of electric remains at setting under current loop control maximum soft stopping allows below the electric current.
In sum, the present invention can realize the soft preferably controlled function of stopping on the basis of soft starter, and the pumping system that has effectively solved Induction Motor-Driven plays the impact in stopping time, surge and noise problem, is that a kind of cost performance is than higher pump controlling schemes.
Claims (5)
1. the soft stop control method of a pump loaded motor comprises the steps:
1.1, enter and softly output to motor again after stopping after the process operating voltage is linked into main circuit;
1.2, control the angle of flow of the thyristor of described main circuit according to predetermined electric moter voltage decline curve;
1.3, gather voltage and electric current that described main circuit outputs to motor;
1.4, voltage and electric current are pressed
Or
Set up Mathematical Modeling, calculate the real-time active power of motor;
1.5, relatively gather difference between the predetermined active power that real-time active power that the voltage and current signal draws and described predetermined electric moter voltage decline harmonic curve draw;
1.6, according to the angle of flow of the described thyristor of discrepancy adjustment between the described active power so that the predetermined voltage of the voltage of described motor trend reduces to zero until the voltage of described motor, soft process of stopping finishes.
2. the soft stop control method of a pump loaded motor wherein, may further comprise the steps:
1.1, enter and softly output to motor again after stopping after the process operating voltage is linked into main circuit;
1.2, control the angle of flow of the thyristor of described main circuit according to predetermined electric moter voltage decline curve;
1.3, gather voltage and electric current that described main circuit outputs to motor;
1.4, voltage and electric current are pressed
Or
Set up Mathematical Modeling, calculate the real-time active power of motor;
1.5, relatively gather difference between the predetermined active power that real-time active power that the voltage and current signal draws and described predetermined electric moter voltage decline harmonic curve draw;
1.6, gather the relatively scheduled current signal of back output;
1.7, gather the electric current that described main circuit outputs to motor;
1.8, will be relatively the electric current exported of electric current and the main circuit of back output compare, draw two differences between all, the angle of flow according to the described thyristor of discrepancy adjustment between the described electric current, so that the predetermined voltage of the voltage of described motor trend, reduce to zero until the voltage of described motor, soft process of stopping finishes.
3. can realize the soft as claimed in claim 1 or 2 device that stops method for one kind, comprise the main circuit that inserts between power supply and the motor, output control device, it is characterized in that, described output control device comprises real-time active power generation module, specified active power generation module, power comparison module, power conditioning module, described real-time active power generation module input links to each other with the output of main circuit, and output links to each other with the input of described power comparison module; The input of described power comparison module also links to each other with described specified active power generation module output, the output of described power comparison module links to each other with the input of described power conditioning module, and the output of described power conditioning module links to each other with described main circuit control end.
4. as a kind of motor soft starter of controlling load of the pumps as described in the claim 3, it is characterized in that described realtime power generation module comprises voltage detection module, current detection module, phase shifting angle detection module, computing module; The input of described voltage, electric current and phase shifting angle detection module is the described main circuit output state that links to each other respectively, and output links to each other with the input of described computing module respectively.
5. as a kind of motor soft starter of controlling load of the pumps as described in the claim 3, it is characterized in that also comprise current control system, described current control system is connected between described main circuit and the described output control device; Described current control system comprises current comparing module, current regulating module, the input of described current comparing module links to each other with the output of described power conditioning module and the output of described main circuit respectively, and the output of described current comparing module links to each other with the input of described current regulating module; The output of described current regulating module links to each other with the control end of described main circuit.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201010101984A CN101719751A (en) | 2010-01-28 | 2010-01-28 | Method and device for soft stop control for pump loaded motor |
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| CN201010101984A CN101719751A (en) | 2010-01-28 | 2010-01-28 | Method and device for soft stop control for pump loaded motor |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105680731A (en) * | 2016-03-30 | 2016-06-15 | 西安西普电力电子有限公司 | AC driver and processing method thereof |
| CN107565860A (en) * | 2017-08-04 | 2018-01-09 | 九阳股份有限公司 | A kind of electric motor starting method of soy bean milk making machine |
| CN109951112A (en) * | 2018-12-22 | 2019-06-28 | 苏州厚盟电子科技有限公司 | It is a kind of for eliminating the control circuit of noise of motor |
| CN113454904A (en) * | 2019-03-12 | 2021-09-28 | 阿莱戈微系统有限责任公司 | Motor controller with power feedback loop |
-
2010
- 2010-01-28 CN CN201010101984A patent/CN101719751A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105680731A (en) * | 2016-03-30 | 2016-06-15 | 西安西普电力电子有限公司 | AC driver and processing method thereof |
| CN107565860A (en) * | 2017-08-04 | 2018-01-09 | 九阳股份有限公司 | A kind of electric motor starting method of soy bean milk making machine |
| CN107565860B (en) * | 2017-08-04 | 2020-10-02 | 九阳股份有限公司 | Motor starting method of soybean milk machine |
| CN109951112A (en) * | 2018-12-22 | 2019-06-28 | 苏州厚盟电子科技有限公司 | It is a kind of for eliminating the control circuit of noise of motor |
| CN113454904A (en) * | 2019-03-12 | 2021-09-28 | 阿莱戈微系统有限责任公司 | Motor controller with power feedback loop |
| US11817811B2 (en) | 2019-03-12 | 2023-11-14 | Allegro Microsystems, Llc | Motor controller with power feedback loop |
| CN113454904B (en) * | 2019-03-12 | 2024-04-05 | 阿莱戈微系统有限责任公司 | Motor controller with power feedback loop |
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