CN1052229A - Stepless speed variator for ac asynchronous motor - Google Patents
Stepless speed variator for ac asynchronous motor Download PDFInfo
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- CN1052229A CN1052229A CN 89106864 CN89106864A CN1052229A CN 1052229 A CN1052229 A CN 1052229A CN 89106864 CN89106864 CN 89106864 CN 89106864 A CN89106864 A CN 89106864A CN 1052229 A CN1052229 A CN 1052229A
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Abstract
A kind of stepless speed variator for AC asynchronous motor that is used for electric drive system.Governor structure novelty of the present invention, the stepless speed regulation of realization AC asynchronous motor under only with the condition of six power ac switch components (thyristor).Its speed adjusting performance when making the motor high-speed cruising near variable-frequency governor.When making the motor low cruise even be better than variable-frequency governor, whole device is simple and reliable, is applicable to the speed governing and the energy-saving no surge start of AC asynchronous motor.
Description
A kind of stepless speed variator for AC asynchronous motor that is used for Electric Traction.
Stepless speed variator for AC asynchronous motor has a wide range of applications in electric drive system, and the past, traditional stepless speed variator for AC asynchronous motor mainly contained variable-frequency governor, becomes revolutional slip speed regulator and electromagnetic slip clutches speed regulator three classes.Though variable-frequency governor good speed adjustment features theoretically wherein; but this speed regulator generally is to be made of a large amount of power switch components and complicated circuits for triggering and protective circuit; structure is huge and complicated; and motor is in very low speed run time behaviour variation; do not reach speed regulation by constant torque, so its practicality and reliability are restricted all.And become revolutional slip speed regulator and electromagnetism and the electromagnetic slip clutches speed regulator all has or not regenerative braking, efficient is low and the shortcoming of speed adjusting performance difference.
It is few that purpose of the present invention is invented a kind of use power switch component at the problems referred to above exactly, control system (circuits for triggering) is simple, reliable operation and speed adjusting performance when making the motor high-speed cruising near variable-frequency governor, when making motor slow-speed of revolution operation even be better than the stepless speed variator for AC asynchronous motor of variable-frequency governor.
Stepless speed variator for AC asynchronous motor of the present invention mainly is made up of two groups of alternating-current switchs and control system protection system thereof; wherein every group of two groups of switches all has the switch number identical with the power supply number of phases of incoming transport asynchronous motor when single-phase (but be two); two groups of switches are connected into like this: the connection of every group of switch all is connected into a kind of phase sequence with AC power and AC asynchronous motor, and two groups of phase sequences that switch is connected into are any different two kinds that make in the homodromal some phase sequences of motor field.Described control system is controlled described two groups reliably and is exchanged the pass, and frequency on demand alternately turns on and off, and after guaranteeing one group of switch reliable turn-off, another group switch is just reliably connected.
Below being arrangement works process and the operation principle that example specifies speed regulator of the present invention as the three-phase AC asynchronous motor stepless speed adjusting gear of alternating-current switch with bidirectional thyristor:
Main circuit of the present invention as shown in Figure 1; mainly be by six bidirectional thyristors and protection component (three inductance L thereof; three quick safety fuse RD; three resistance R and three capacitor C) form; six bidirectional thyristors are to be divided on two groups of CAB and two kinds of phase sequences of ABC that are connected on motor respectively as can be seen from Figure, the alternate conduction of two groups of bidirectional thyristors and by being realized by Fig. 2 or circuits for triggering shown in Figure 3.Seeing Fig. 2 earlier, is a triggering power supply by transformer coupled isolation output in the dashed rectangle, and it is corresponding with the thyristor grouping of Fig. 1 main circuit that it triggers output, also is by g
1g
2g
3Synchronous triggering and g
4g
5g
6Synchronous triggering is divided into two groups, and be connected on respectively with the corresponding terminal of Fig. 1 main circuit on, the triggering signal that triggers power supply is taken from two output U of the complementary time-delay of Frequency Adjustable square-wave generator
1U
2And the effect of (for power frequency) generator of the high frequency in the triggering power supply and power amplifier provides the power of output triggering and the volume of the isolating output transformer that reduces to be coupled.The effect of the complementary time-delay of Frequency Adjustable square-wave generator is complementary and square wave U that the rising edge time-delay triggers with certain frequency (this frequency is adjustable, also can be designed to self-regulating) output two row
1And U
2Delay time is t as shown in Figure 4
W, the purpose of this delay time setting be make have only one group of thyristor reliable turn-off after, another group could triggering and conducting.The frequency that changes this square-wave generator just can change two groups of bidirectional thyristor alternate conduction and the frequency of ending, and has also just changed the three-phase alternating current electrical alternations and has been connected on the frequency of the homodromal two kinds of phase sequences of threephase asynchronous, thereby changed motor speed.The difference of circuits for triggering shown in Figure 3 and Fig. 2 only is that it triggers power supply is to adopt the photoelectricity coupling to isolate, and other are then identical with Fig. 2.
The course of work of speed regulator of the present invention is: the complementation time-delay that control system is sent certain frequency by the complementary time-delay of frequency modulation square-wave generator triggers square-wave signal (as Fig. 4) and isolates by transformer coupled isolation or photoelectricity coupling and trigger power supply and control two groups of bidirectional thyristors with the alternately conducting and ending of certain adjustable frequency, thereby the control three-phase alternating-current supply with certain adjustable frequency alternately switching motor realize the stepless speed regulation of AC asynchronous motor with two kinds of phase sequences that turn to.
The following describes with certain frequency make three-phase alternating current alternately changing-over change the principle of motor speed in the homodromal two kinds of phase sequences of threephase asynchronous:
Well-known three-phase alternating current (being made as X, y, Z three-phase) has six kinds of different phase sequences at three phase times of incoming transport asynchronous motor, is ABC, BCA, CAB, CBA, BAC, ACB; Wherein first three kind phase sequence makes magnetic field just change back three kinds of then counter-rotatings, and makes the phase place of the homodromal three kinds of phase sequences in magnetic field that difference be arranged mutually, and mutual deviation is 120 ° when the three-phase alternating current symmetry.If get any two kinds that make in the homodromal three kinds of phase sequences in magnetic field like this, as ABC, CAB, ABC among the BCA and CAB alternately insert three-phase alternating current XyZ with them with certain frequency, promptly as shown in Figure 1, following situation then takes place: as shown in Figure 5 when motor connects electric phase sequence and becomes CAB by the ABC changing-over, phase sequence after the changing-over lags behind phase sequence 120 degree before the changing-over, when again the CAB phase sequence that is connect being gained into the ABC phase sequence behind the certain hour, and ABC phase sequence CAB phase sequence 240 degree that lag behind again then.Dotted line is represented each phase place that changing-over is preceding among the figure, solid line is represented each phase place after the changing-over, band arrow camber line is represented angle of retard, so continuous circulation goes down just to cause stator field constantly to rotate to a direction with synchronous speed on the one hand, on the other hand again constantly with 120 degree, two kinds of angles of 240 degree alternately lag behind, each changing-over all forms the dynamic brake state that stator field is drawn in the rotor field in angle of retard in a period of time less than 180 degree, it is the regenerative braking state, comprehensive function is in the result of rotor like this, is rotated on the rotating speed that is lower than former quota rotating speed with making rotor stability.Alternately the frequency of changing-over phase sequence is high more, the speed that the stator rotating magnetic field lags behind is just fast more, then rotor speed is low more, otherwise the frequency of changing-over is low more, then rotor speed is high more, thereby realized the stepless speed regulation of motor, here of particular note: how to replace changing-over with three kinds of phase sequences that turn to and to think that all the magnetic field phase place after the changing-over is ahead of the preceding magnetic field phase place of changing-over, here because the rotation of stator field is depended in the rotation in AC asynchronous motor rotor and magnetic field thereof fully, promptly be result by the induction of stator rotating magnetic field, and the rotating speed of stator field is invariable and be higher than the rotating speed of rotor forever, therefore when thereby the homodromal different phase sequences of changing-over make stator and rotor field phase place inconsistent, have only rotor and rotor field rotating speed to slow down to make stator field " catch up with " rotor field and obtain the consistent of the two phase place, thereby and be that rotor quickens rotation with the rotor field and make the rotor field rotating speed surpass stator rotating magnetic field rotating speed " to catch up with " the stator rotating magnetic field and obtain the consistent of the two phase place till the ass ascends the ladder.For the effect of asynchronous motor stator the action of a magnetic field in rotor, changing-over can only cause the hysteresis of stator field with the different phase sequences that turn to, and can not be leading thus.Exist a kind of technology prejudice for many years about this point: promptly think and just think that naturally the phase place of this another kind of phase sequence ABC is ahead of this this angle of phase sequence CAB phase place (120 degree) if a kind of phase sequence such as CAB phase place lag behind another kind of phase sequence such as ABC phase place certain angle (being 120 degree as mentioned above) always, so also just think naturally if these two kinds of phase sequences replace changing-over, then act on also just inevitable low mutually the disappearing of effect of rotor, leading again 120 degree of 120 degree that promptly lag behind, thus also have with regard to the speed governing effect with regard to having no way of.The present invention is then from analyzing asynchronous motor rotor magnetic field fully according to belonging to stator field, this particular kind of relationship as a result that is the stator field induction is started with, having broken this technology prejudice for many years through testing repeatedly, invented this stepless speed variator for AC asynchronous motor, is a kind of creation.
If stepless speed adjusting gear of the present invention is exclusively used in the starting of asynchronous motor, then only need and to change (motor speed is changed to rated speed automatically by zero) with the frequency that turns to different phase sequences to replace changing-over automatically by from high to low rule, and after starting finishes, excise this speed regulator automatically, motor is directly received made it normal operation on the AC power simultaneously.
The present invention compares with existing stepless speed variator for AC asynchronous motor has following excellent characteristics:
1, speed adjusting performance is superior, the efficient height:
Stepless speed adjusting gear of the present invention makes asynchronous motor drag slip work between the state in dynamic brake and power, braking energy is directly sent electrical network back to by generating, therefore speed regulator of the present invention has regenerative braking and the high characteristics of efficient when speed governing is worked, can make the rapid lifting speed of motor, also exportable big torque not only operates steadily when making the motor low cruise, its performance even be better than variable-frequency governor, this speed regulator also has higher adjusting speed accuracy in addition, can rest on accurately on any rotating speed in the low-speed range, and can guarantee the specified torque of output on each rotating speed.This speed regulator can carry out stepless speed regulation or energy-conservation starting to many asynchronous motors as a kind of control power supply in addition.
2, simple in structure, the reliability height, cost is low:
Stepless speed adjusting gear of the present invention is as long as six power switch components (thyristor) are minimum with power switch component in the existing various stepless speed adjusting gears.And cause circuits for triggering very simple therefrom, thus the reliability of this speed regulator is greatly improved, and cost reduces significantly.
3, applicable surface is extensive:
Speed regulator of the present invention is owing to have above-mentioned two excellent characteristics, adopted the occasion that becomes the revolutional slip speed regulator to raise the efficiency before therefore it both has been applicable to, energy savings, improve speed adjusting performance, adopt the occasion of variable-frequency governor before also being applicable to, to reduce cost, improve reliability, even be applicable to that also the occasion that adopts mechanical speed governors in the past with weight reduction, reduces volume, reduce cost.And can replace the use of DC motor in very wide scope.If the starting that is exclusively used in asynchronous motor of this speed regulator not only is being better than frequency reducing starter (output torque output torque greater than with the frequency reducing starter time during at very low speed) on the starting performance in addition, but bringing onto load starting, and because cost simple in structure is low, so can promote the use of on a large scale.Adopt this starting device at first can avoid the impact of electric motor starting to electrical network, can save the harm of power supply unit expense (mainly being to reduce the supply transformer capacity) release to other power consumption equipment, secondly can save a large amount of electric energy, this is because starting current is lower than the cause of other method of starting.
The enforcement of stepless speed adjusting gear of the present invention; with the different of condition multiple different scheme can be arranged as requested; in fact in main circuit, must there be two groups of power switch components that power supply and motor are connected into two kinds of phase sequences that make the rotation of motor homophase; its circuits for triggering then have various different form with protective circuit; its function is also different; can be manual governing, also can be that automatic speed regulation can be taked common simple Pulse-trigger control, also can adopt intelligent digital control.Fig. 6 and Fig. 7 (and in conjunction with Fig. 1) are depicted as the examples of implementation of two common simple Pulse-trigger control.Different apparent Fig. 6 adopt transformer coupled isolation to trigger power supply, Fig. 7 adopts the photoelectricity coupling to isolate to trigger power supply, triggering signal is then all come free two ic 555s when basic and resistance, the complementary time-delay of the Frequency Adjustable that electric capacity and diode are formed square-wave generator, wherein R
1R
2C
1D
1And R
3R
4C
2D
2Form two time-delays respectively and trigger link and R
W1C
3And R
W2C
4Reach two 555 and form the Frequency Adjustable oscillator together, by two 555 the complementary time-delay of outputs output two row square wave U
1, U
2, as shown in Figure 4, adjusted in concert R
W1And R
W2Then scalable is exported the frequency of square wave, thereby regulates motor speed.
Claims (3)
1, a kind of stepless speed variator for AC asynchronous motor that is used for AC asynchronous motor stepless speed regulation.It is characterized in that being made up of some ac switch components and control system thereof and protection system: described switch element such as is divided at two groups of number.Every group of switch number is identical with the power supply number of phases of incoming transport asynchronous motor.They are connected into like this: the connection of every group of switch all is connected into a kind of phase sequence with AC power and AC asynchronous motor, and two groups of phase sequences that switch was connected into are any different two kinds that make in the homodromal some phase sequences of motor field.Described control system is controlled described two groups of switch elements reliably, and adjustable on demand frequency alternately turns on and off, and after guaranteeing one group of switch reliable turn-off.Another group switch is just reliably connected.Described protection system is protected the ground work of described switch element normal reliable.
2, according to the described stepless speed variator for AC asynchronous motor of claim 1; it is characterized in that being made up of six bidirectional thyristors and circuits for triggering thereof and protective circuit: described six bidirectional thyristors are divided into two groups and be connected into like this by three every group: the conducting of every group of thyristor all is connected into a kind of phase sequence with three-phase alternating-current supply and three-phase AC asynchronous motor, and two groups of phase sequences that switch was connected into are any different two kinds that make in the homodromal three kinds of phase sequences of motor field.Described circuits for triggering are by DC power supply, the complementary time-delay of Frequency Adjustable square-wave generator, and transformer coupled isolation or photoelectricity coupling are isolated the triggering power supply and are formed.They make two groups of adjustable on demand frequencies of bidirectional thyristor obtain triggering and conducting alternately and end.And guarantee that one group of thyristor is reliable fully by the just reliable conducting of another group of back.Described protective circuit is by three inductance L, three quick safety fuse RD, and three resistance R and three capacitor C are formed, and they are connected on respectively on the threephase asynchronous major loop.The protection bidirectional thyristor is worked reliably.
3, according to the described stepless speed variator for AC asynchronous motor of claim 1, it is characterized in that: when being exclusively used in motor starting, described control system is controlled frequency that described two groups of switches alternately turn on and off and is changed automatically up to the starting back described two groups of switches of excision and motor directly received on the power supply automatically that finish by from high to low rule, thereby constitutes the device of described stepless accent device special-purpose: the AC asynchronous motor energy-saving starter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 89106864 CN1052229A (en) | 1989-11-30 | 1989-11-30 | Stepless speed variator for ac asynchronous motor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 89106864 CN1052229A (en) | 1989-11-30 | 1989-11-30 | Stepless speed variator for ac asynchronous motor |
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| Publication Number | Publication Date |
|---|---|
| CN1052229A true CN1052229A (en) | 1991-06-12 |
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ID=4856935
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 89106864 Pending CN1052229A (en) | 1989-11-30 | 1989-11-30 | Stepless speed variator for ac asynchronous motor |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105429552A (en) * | 2015-12-28 | 2016-03-23 | 天津市福锐达电气成套设备工程有限公司 | Three-phase reversible thyristor system |
| CN105450133A (en) * | 2015-12-28 | 2016-03-30 | 天津市福锐达电气成套设备工程有限公司 | Three-phase thyristor system with dynamic braking |
-
1989
- 1989-11-30 CN CN 89106864 patent/CN1052229A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105429552A (en) * | 2015-12-28 | 2016-03-23 | 天津市福锐达电气成套设备工程有限公司 | Three-phase reversible thyristor system |
| CN105450133A (en) * | 2015-12-28 | 2016-03-30 | 天津市福锐达电气成套设备工程有限公司 | Three-phase thyristor system with dynamic braking |
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