CN102111096B - Method for preventing asynchronous motor from shocking during soft start - Google Patents
Method for preventing asynchronous motor from shocking during soft start Download PDFInfo
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- CN102111096B CN102111096B CN201110047287XA CN201110047287A CN102111096B CN 102111096 B CN102111096 B CN 102111096B CN 201110047287X A CN201110047287X A CN 201110047287XA CN 201110047287 A CN201110047287 A CN 201110047287A CN 102111096 B CN102111096 B CN 102111096B
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Abstract
The invention relates to a method for preventing an asynchronous motor from shocking during soft start. An effective phase shift angle gamma of a thyristor can be determined only by detecting voltages at both ends of a bidirectional thyristor instead of detecting a power factor angle phi in the soft start operation of the asynchronous motor. Through the dynamic regulation of thyristor phase shift angle alpha according to the effective phase shift angle gamma of the thyristor, the stability of the effective phase shift angle gamma of the thyristor is kept and the vibration in the process of the soft start of the asynchronous motor is reduced or eliminated. When the method provided by the invention is used, secondary impact currents cannot be generated in the motor, so that the requirements of the soft start of the asynchronous motor are better met, and the functions of light load voltage regulation and energy conservation of the asynchronous motor can be fulfilled.
Description
Technical field
The invention belongs to Motor Control and single chip microcomputer applied technical field, be specifically related to a kind of method that prevents the Soft-starting Asynchronous Motors concussion.
Background technology
Adopting the Soft Starter of Induction Motor of thyristor phase-shift voltage regulating to have that volume is little, lightweight, originate mode is many, control the advantages such as flexible, is one of scheme of current Soft-starting Asynchronous Motors first-selection.But the harmonic voltage electric current that the thyristor phase-shift voltage regulating produces, can affect the starting operation performance of asynchronous motor, be embodied in, the starting torque of asynchronous motor reduce and produce the pulsation moment, its pulsation moment can cause the fluctuation of asynchronous motor speed, and the fluctuation of asynchronous motor speed can cause the fluctuation of Asynchronous Motor Power Factor angle Φ again.
The thyristor phase-shift voltage regulating system adopted at present, control to as if with respect to the phase shifting angle α of supply voltage zero crossing, and in Starting Process of Induction Motor, when relative speed variation is larger, the power-factor angle Φ fluctuation of motor is larger, cause effective phase shifting angle γ fluctuation of thyristor phase-shift voltage regulating larger, and then cause the asynchronous electric set end voltage to change greatly, motor produces significantly concussion.In order to reduce the motor concussion, the technical measures that soft start at present adopts are, when motor speed starts fast rise, when starting current obviously descends, immediately asynchronous motor is added to full voltage, avoided the fluctuation of asynchronous electric set end voltage, prevented the concussion of asynchronous motor.But when existing the impact total head, the method can produce larger secondary pulse electric current, and all unfavorable to motor and electrical network.
Summary of the invention
The present invention seeks to a kind of method that prevents Soft-starting Asynchronous Motors concussion, can direct-detection to the effective phase shifting angle γ of thyristor, and, by dynamic adjustments thyristor phase shifting angle α, reach and prevent from producing and shaking in Soft-Starting of Induction Motor.
The present invention is achieved in that a kind of method that prevents the Soft-starting Asynchronous Motors concussion, need not detect the operating power-factor angle Φ of Soft-starting Asynchronous Motors, only by detecting the bidirectional thyristor both end voltage, just can judge effective phase shifting angle γ of thyristor, effective phase shifting angle γ according to thyristor, dynamic adjustments thyristor phase shifting angle α, reach and keep the stable of the effective phase shifting angle γ of thyristor, reduces or eliminates the reforming phenomena in Soft-Starting of Induction Motor.
The resistance and the photoelectrical coupler that are connected in parallel on the bidirectional thyristor two ends can detect thyristor turn-on and turn-off interval, and turn-off interval corresponding electrical degree, are exactly effective phase shifting angle γ of thyristor.
The effective phase shifting angle γ of the detected thyristor of photoelectrical coupler delivers in DSP or single-chip microcomputer, according to the effective phase shifting angle γ of detected thyristor and the deviation of setting the effective phase shifting angle of thyristor, adopt the dynamic thyristor phase shifting angle of Closed-loop Control Strategy α, and then keep the effective phase shifting angle γ of thyristor stable, reach and keep the stable purpose of asynchronous motor.
Described bidirectional thyristor can also adopt the reverse parallel connection of two unidirectional thyristors to form.
A kind of method that prevents the Soft-starting Asynchronous Motors concussion of the present invention, by detecting the voltage at bidirectional thyristor two ends, can judge effective phase shifting angle γ of thyristor, and then dynamic adjustments thyristor phase shifting angle α, keep effective phase shifting angle γ of thyristor stable, reach and reduce or eliminate the purpose of shaking in Starting Process of Induction Motor, the stable operation that also can guarantee asynchronous motor in service of asynchronous motor pressure regulating energy-saving.
Adopt the inventive method, can not produce the secondary pulse electric current to motor, therefore more meet the requirement of Soft-starting Asynchronous Motors, can also realize the function of asynchronous motor during fractional load pressure regulating energy-saving.
The accompanying drawing explanation
Below in conjunction with drawings and Examples, the invention will be further described:
Fig. 1 is three-phase main circuit theory diagram of the present invention;
Fig. 2 is that the single-phase main circuit of the present invention detects the interval schematic diagram of thyristor break-make;
Fig. 3 is that the present invention detects the effective phase shifting angle γ of thyristor oscillogram.
Embodiment
The invention provides the method for the effective phase shifting angle γ of a kind of energy direct-detection thyristor, as shown in Figure 1, three-phase main circuit A, B, C are every by after a resistance and the series connection of a pair of photoelectrical coupler, being connected in parallel on bidirectional thyristor, also can be by two unidirectional thyristor inverse parallels formations.The A of take is example mutually, bidirectional thyristor or two unidirectional thyristor inverse parallels, its two ends are A1, A2 end, when the bidirectional thyristor conducting, the former side's light-emitting diode of photoelectrical coupler no current passes through, photoelectrical coupler pair side output high level, when bidirectional thyristor ends, a light-emitting diode in photoelectrical coupler has electric current to pass through, corresponding photoelectrical coupler pair side output low level, the width of photoelectrical coupler pair side output low level, i.e. the effective phase shifting angle γ of corresponding thyristor, as shown in Figure 2.
The effective phase shifting angle γ of the thyristor of detection is sent into to DSP, and with the given thyristor in Soft-Starting of Induction Motor, effective phase shifting angle γ compares, and removes to control the output voltage of thyristor soft starter after PI regulates as the working control phase shifting angle α of soft initiator.Due to given thyristor, effective phase shifting angle γ is stable, and in Starting Process of Induction Motor, power-factor angle Φ fluctuates, therefore the working control phase shifting angle α of soft initiator is dynamic adjustments, thereby reach the purpose of stablizing thyristor soft starter output voltage, reduced or eliminated the reforming phenomena of Starting Process of Induction Motor.
The method expands in the asynchronous motor during fractional load voltage-regulating and energy-saving controller and uses, be operated in the non-full conducting operating mode of thyristor when the asynchronous motor during fractional load due to the asynchronous motor during fractional load voltage-regulating and energy-saving controller, the variation of motor load can cause the fluctuation of motor power factor angle Φ, adopt current thyristor phase-shifting control method, may cause the concussion of motor.And adopt new method provided by the invention, and can stablize the triac controller output voltage, reduce or eliminate the operating reforming phenomena of asynchronous motor during fractional load pressure regulating energy-saving.
Embodiment:
The present invention is applied to a set of 50KW Soft Starter of Induction Motor, and main circuit as shown in Figure 1.Main circuit consists of the three-phase anti-parallel thyristor, and every phase anti-parallel thyristor two ends are parallel with a resistance and two testing circuits that photoelectrical coupler is in series, and this testing circuit can detect the on off operating mode of every phase thyristor.The design parameter of testing circuit is illustrated in fig. 2 shown below: first resistance R 1=100K Ω/2W connects, minimum power factor angle Φ in Starting Process of Induction Motor=30 degree, the minimum current of first resistance R 1 of therefore flowing through is (380V*sin30 °)/100 K Ω=1.9mA, the maximum current of first resistance R 1 of flowing through is 380V/100 K Ω=3.8mA, the maximum power P=380V*3.8mA=1.44W that the first resistance R 1 is born, the resistance of choosing can meet the demand that detects electric current.Photoelectrical coupler G1, G2 adopt PC817, and its current transfer ratio minimum is 0.5, therefore output sampling the second resistance R 2=R3=5V/0.9mA=5.5K Ω gets the 2nd R2=R3=5.6 K Ω in fact.In Fig. 2, Usc1 and Usc2 output is square wave voltage signal, as shown in Figure 3, this square wave signal shaping after filtering, after eliminating the impact of disturbing pulse, give the mouth of catching of digital signal processor DSP, DSP is converted to the high level width of the output voltage U sc1 of filter shape, Usc2 the effective phase shifting angle γ of thyristor of digital quantity.According to different soft start patterns, as: voltage ramp, current ramp, determine electric current etc., calculate the effective phase shifting angle set-point of thyristor γ, difference to the effective phase shifting angle set-point of thyristor γ g and the effective phase shifting angle measured value of thyristor γ is carried out the PI adjusting, its output is as the working control phase shifting angle α of thyristor soft starter, the output voltage obtained can not fluctuate with the fluctuation of motor power factor angle Φ, can reduce or eliminate the concussion in Starting Process of Induction Motor.
Claims (1)
1. a method that prevents Soft-starting Asynchronous Motors concussion, it is characterized in that: need not detect the operating power-factor angle Φ of Soft-starting Asynchronous Motors, only by detecting the bidirectional thyristor both end voltage, just can judge effective phase shifting angle γ of thyristor, effective phase shifting angle γ according to thyristor, dynamic adjustments thyristor phase shifting angle α, reach and keep the stable of the effective phase shifting angle γ of thyristor, reduces or eliminates the reforming phenomena in Soft-Starting of Induction Motor;
The resistance and the photoelectrical coupler that are connected in parallel on the bidirectional thyristor two ends can detect thyristor turn-on and turn-off interval, and turn-off interval corresponding electrical degree, are exactly effective phase shifting angle γ of thyristor;
The effective phase shifting angle γ of the detected thyristor of photoelectrical coupler delivers in DSP or single-chip microcomputer, according to the effective phase shifting angle γ of detected thyristor and the deviation of setting the effective phase shifting angle of thyristor, adopt the dynamic thyristor phase shifting angle of Closed-loop Control Strategy α, and then keep the effective phase shifting angle γ of thyristor stable, reach and keep the stable purpose of asynchronous motor;
Bidirectional thyristor can also adopt the reverse parallel connection of two unidirectional thyristors to form.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110047287XA CN102111096B (en) | 2011-02-28 | 2011-02-28 | Method for preventing asynchronous motor from shocking during soft start |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201110047287XA CN102111096B (en) | 2011-02-28 | 2011-02-28 | Method for preventing asynchronous motor from shocking during soft start |
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| CN102111096A CN102111096A (en) | 2011-06-29 |
| CN102111096B true CN102111096B (en) | 2013-12-04 |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0887905A2 (en) * | 1997-06-26 | 1998-12-30 | Mita-Teknik A/S | Procedure to connect an asynchronous generator on an alternating current and an electrical connecting for use at this procedure |
| CN2547064Y (en) * | 2002-04-12 | 2003-04-23 | 濮阳中原石油机械有限公司 | Flexible starting and energy-saving controller for motor |
| CN201290092Y (en) * | 2008-09-10 | 2009-08-12 | 江苏省电力公司盐城供电公司 | Pressure-regulating and energy-saving controller for asynchronous motor |
| CN101512887A (en) * | 2006-09-11 | 2009-08-19 | Abb公司 | Method and device for reducing the influence of a DC component in a load current of an asynchronous three-phase motor |
| CN201742355U (en) * | 2010-01-28 | 2011-02-09 | 扬中市丰顺电器有限公司 | Motor soft starter for controlling pump type load |
| CN201742356U (en) * | 2010-01-28 | 2011-02-09 | 扬中市丰顺电器有限公司 | Digital type intelligent soft-starting device |
-
2011
- 2011-02-28 CN CN201110047287XA patent/CN102111096B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0887905A2 (en) * | 1997-06-26 | 1998-12-30 | Mita-Teknik A/S | Procedure to connect an asynchronous generator on an alternating current and an electrical connecting for use at this procedure |
| CN2547064Y (en) * | 2002-04-12 | 2003-04-23 | 濮阳中原石油机械有限公司 | Flexible starting and energy-saving controller for motor |
| CN101512887A (en) * | 2006-09-11 | 2009-08-19 | Abb公司 | Method and device for reducing the influence of a DC component in a load current of an asynchronous three-phase motor |
| CN201290092Y (en) * | 2008-09-10 | 2009-08-12 | 江苏省电力公司盐城供电公司 | Pressure-regulating and energy-saving controller for asynchronous motor |
| CN201742355U (en) * | 2010-01-28 | 2011-02-09 | 扬中市丰顺电器有限公司 | Motor soft starter for controlling pump type load |
| CN201742356U (en) * | 2010-01-28 | 2011-02-09 | 扬中市丰顺电器有限公司 | Digital type intelligent soft-starting device |
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| CN102111096A (en) | 2011-06-29 |
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