CN2704965Y - Flexible starting controller of asychronous motor - Google Patents
Flexible starting controller of asychronous motor Download PDFInfo
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- CN2704965Y CN2704965Y CN 200420035092 CN200420035092U CN2704965Y CN 2704965 Y CN2704965 Y CN 2704965Y CN 200420035092 CN200420035092 CN 200420035092 CN 200420035092 U CN200420035092 U CN 200420035092U CN 2704965 Y CN2704965 Y CN 2704965Y
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Abstract
The utility model discloses a flexible starting controller for asychronous motor of silicon-controlled pressure regulating control technique. By improving pressure regulating ratio formula of silicon controlled zero-crossing trigger and controlling gating signal of silicon-controlled trigger, the starting voltage of the motor is controlled without harmonic interference on electrical network, and even running of the motor is guaranteed. The controller is composed of the parts of a microprocessor(1), a bidirectional controlled silicon(2) and a zero-crossing trigger(3), an LCD display screen (4), a plurality of keys(5) and indicator lights(8), an electric-current feedback element(6), an alternating current contactor(7), etc. The controlled object is an asynchronous motor(9).
Description
Affiliated technical field
The utility model relates to and utilizes controllable silicon that three-phase AC asynchronous motor is carried out the control technology of voltage-regulation, is used for the soft start control of asynchronous motor, both electrical network is not had Harmonic Interference, can guarantee the motor even running again.
Background technology
Traditional asynchronous motor reduced-voltage starting mode has the startup of Y-Δ conversion decompression, autotransformer reduced-voltage starting, stator loop series resistor device reduced-voltage starting etc., though its advantage and practicality are respectively arranged, is progressively replaced by novel electronic formula soft starting mode.Asynchronous motor soft start controller at present commonly used adopts controllable silicon phase shift triggering mode more, changes average voltage in the unit interval by control silicon controlled trigger angle β, realizes the stepless control to motor power voltage.
But the soft start controller that adopts the phase shift triggering has exactly also been lost a common advantage of traditional reduced-voltage starting mode in the shortcoming that has overcome various traditional reduced-voltage starting modes---electrical network there is not Harmonic Interference (pollution).Because the phase shift triggering mode has directly caused the distortion of power supply wave shape, make primary sinusoid deformation become nonsinusoidal waveform.
Controllable silicon has two kinds of triggering modes---phase shift triggering and zero cross fired.And the silicon control zero-cross triggering mode exactly can be avoided the distortion of power supply wave shape, makes electrical network avoid harmonic pollution.It can change the average voltage in the unit interval by control silicon controlled turn-on cycle number, realize the control to motor power voltage, and the resulting voltage waveform of motor terminal is complete sine wave.Its pressure regulation than computing formula is:
n
1, n
2Be natural number, and n
1≤ n
2
But, at the non-conduction cycle (n of silicon controlled
2-n
1Interval), motor continues to rotate (this is the same with 0～β interval in the phase shift firing control) by inertia.If obtain certain pressure regulation and make the non-conduction cycle oversize (as n than the K value
2-n
1〉=3 cycles), will cause motor discontinuity rotation (impulsion), even stall, can burn out motor when serious.
Summary of the invention
For guarantee that voltage waveform distortion neither takes place asynchronous motor in the pressure regulation process, again can even running, the utility model proposes a kind of modified model silicon control zero-cross triggering technique, can realize the Regulation Control purpose easily.
The technical solution of the utility model is:
At first the pressure regulation to zero trigger mode improves than computing formula, introduces that a new definition---the conducting half period is compared K
h, its pressure regulation than computing formula is:
N is a natural number
In the formula (2), n desirable 2,3,4 ... 100 (i.e. 1 cycle, 1.5 cycles, 2 cycles ... 50 cycles), correspondingly, K then
h=1/2 (=50%), 2/3 (=66.7%), 3/4 (=75%) ... 99/100 (=99%).That is to say, no matter K
hHow many (or n) values gets, the non-conduction time of controllable silicon in a unit interval always has only half period (be π, for power frequency 50Hz AC power, be 10ms), this just makes the discontinuity rotation of motor reach minimum at interval, has guaranteed the even running of motor effectively.As seen, by control n value, i.e. may command K
hValue obtains needed control magnitude of voltage, realizes the soft start control of motor.
Secondly, for enlarging range of regulation (K in the following formula
hValue only be 50%～100%), and reduce the differential (K in the following formula of pressure regulation
hIn the classification below 75% 50%, 66.7% two-stage is only arranged), the utility model further passes through the width of the gate-control signal of control silicon control zero-cross trigger element, and the discontinuity rotation of motor can be selected in π, 4 π/3,5 π/3 third gear at interval.
So pressure regulation can further change into than computing formula:
K is compared in pressure regulation
hValue also can obtain for 33.3%, 44.4%, 55.6%, 58.3%, 72.2% etc. (also can get more thinner more than 75%) at different levels.Like this, both enlarge range of regulation (33.3%～100%), reduced differentially again, and can satisfy the needs of practical application fully.
The technical solution that the utility model adopted is: soft start controller mainly is made up of microprocessor (can be single-chip microcomputer or programmable controller PLC or digital signal processor DSP), bidirectional triode thyristor and over-zero trigger, current feedback link, LCD display, A.C. contactor, plurality of keys and indicator light etc.The three-phase power line of motor respectively is connected in series a bidirectional triode thyristor, adopts the zero trigger mode shown in the formula (3), by the silicon controlled conducting half period in the control unit interval, realizes the control to the motor input voltage; The current feedback link is made up of Hall current transmitter and A/D converter, the Hall current transmitter can be converted to 0～5V d. c. voltage signal in proportion with the input AC electric current of motor major loop, through A/D converter aanalogvoltage is converted to digital signal again and offers microprocessor (considering that asynchronous motor is a symmetric three-phase load) so only the arbitrary phase current that detects wherein gets final product; The LCD demonstration is used to show motor operational factor that preset and current; Button, indicator light are used to preset the operational factor and the operating state of (demonstration) motor, and the start and stop of control motor.A.C. contactor is used for motor start-up switches bidirectional triode thyristor after finishing, and makes the operation of motor total head.
The soft start control system course of work: at first, according to motor load situation and job requirement, select to start curve, operational factor be set (LCD display can show startup curve code name and operational factor simultaneously) with presetting button, then, press the startup button, motor begins to start, and microprocessor is according to the operational factor that presets and the feedback parameter of actual measurement, and the conducting half period of control bidirectional triode thyristor is compared K
hThereby, the input voltage and the rotating speed of control motor.When treating that soft start finishes, the A.C. contactor that closes automatically switches and falls bidirectional triode thyristor, the operation of motor total head.
The beneficial effects of the utility model are:
1. can not distort at voltage waveform, do not produce under the situation of Harmonic Interference, guarantee the motor even running, the effect in the control of asynchronous motor soft start is better than phase shift triggering mode and conventional zero trigger mode.
2. on the basis of this soft start controller, increase a speed feedback link, also can be used for the variable voltage control control of asynchronous motor.
3. this soft start controller simple in structure, control convenient, functional, reliable operation.
Description of drawings
The utility model is described in further detail below in conjunction with accompanying drawing.
Fig. 1 is a structural principle block diagram of the present utility model.Controller is made up of microprocessor (1), bidirectional triode thyristor (2) and over-zero trigger (3) thereof, LCD display (4), plurality of keys (5) and indicator light (8), current feedback link (6), A.C. contactor parts such as (7), and controlling object is asynchronous motor (9).
Fig. 2 is bidirectional triode thyristor and over-zero trigger control circuit figure (A circuitry phase line has only drawn among the figure) thereof among the embodiment of the present utility model.
Fig. 3 is over-zero trigger gate-control signal oscillogram (control signal at P3.0 place in the corresponding diagram 2).T is a unit interval among the figure, and Ton is the control gate opening time in the unit interval, and Toff is the control gate shut-in time in the unit interval.
Embodiment
Referring to Fig. 2, the utility model is selected the over-zero trigger of the MOC3041 series zero passage detection photoelectricity coupling two-way scr triggering device of MOTOROLA company as main bidirectional triode thyristor TRIAC for use, this over-zero trigger have with input signal synchronously, strong and weak electricity photoelectricity isolates, the controlled function of output pulse, uses very simple and reliable.The two poles of the earth of main bidirectional triode thyristor TRIAC1 and the A A.C. contactor JC contact parallel connection of power circuit mutually, its control utmost point links to each other with the pin 4 of MOC3041.The gate-control signal of MOC3041 is provided by an I/O pin P3.0 of microprocessor (being single chip computer AT 89C52 in the present embodiment), when P3.0 is low level, make the pin 2 of MOC3041 be low level through a driver 7407A, the interior light emitting diodes conducting, the zero cross fired pulse can offer the control utmost point of main bidirectional triode thyristor TRIAC1, make the TRIAC1 conducting, motor A phase power connection; When P3.0 was high level, interior light emitting diodes was ended, and the zero cross fired pulse can't offer TRIAC1, so TRIAC1 ends, motor A phase power supply disconnects.
When microprocessor was programmed, the respective value with Kh and T, Ton deposited memory in advance.During work, according to needed Kh value, obtain corresponding with it T, Ton value by look-up routine, call the timer subprogram again, the output level that makes the P3.0 pin can make motor obtain required control magnitude of voltage along with T, Ton value change.
Claims (2)
1, a kind of asynchronous motor soft start controller, it is characterized in that: soft start controller is made up of microcontroller (1), bidirectional triode thyristor (2) and over-zero trigger (3) thereof, LCD display (4), button (5) and indicator light (8), current feedback link (6), A.C. contactor (7) etc., an output pin of microcontroller (1) is connected with the gate-control signal of over-zero trigger (3), and the output signal of over-zero trigger (3) is connected with the control utmost point of bidirectional triode thyristor (2).
2, asynchronous motor soft start controller according to claim 1 is characterized in that: respectively connect a bidirectional triode thyristor (2) on the three-phase power line of asynchronous motor (9).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200420035092 CN2704965Y (en) | 2004-02-11 | 2004-02-11 | Flexible starting controller of asychronous motor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200420035092 CN2704965Y (en) | 2004-02-11 | 2004-02-11 | Flexible starting controller of asychronous motor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2704965Y true CN2704965Y (en) | 2005-06-15 |
Family
ID=34773179
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200420035092 Expired - Fee Related CN2704965Y (en) | 2004-02-11 | 2004-02-11 | Flexible starting controller of asychronous motor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2704965Y (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111490478A (en) * | 2020-02-12 | 2020-08-04 | 贵州振华群英电器有限公司（国营第八九一厂） | Standard machine box type intelligent comprehensive power distribution structure |
-
2004
- 2004-02-11 CN CN 200420035092 patent/CN2704965Y/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111490478A (en) * | 2020-02-12 | 2020-08-04 | 贵州振华群英电器有限公司（国营第八九一厂） | Standard machine box type intelligent comprehensive power distribution structure |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |