CN105915149A - Motor rotating speed accurate identification method after outage in interrupted power supply energy saving control - Google Patents

Abstract

The present invention belongs to the field of the motor energy saving control technology, and especially relates to a motor rotating speed accurate identification method after outage in an interrupted power supply energy saving control. After a motor power supply is cut off, the rotation speed is detected by using the motor stator winding residual voltage; when the residual voltage is decreased to a 10% of a rated voltage, a single-chip microcomputer is employed to control a silicon controlled rectifier device to power on any one phase winding so as to allow the rotor silver to induct electromotive force and current; and after any one phase winding of the stator powers on, the stator winding is cut by using the magnetic field rotating with the rotor generated in the space according to the current inducted at the rotor side, induction electromotive force corresponding to the rotor rotating speed is inducted, and the single-chip microcomputer is used for determining the induction electromotive force frequency to complete the accurate identification of the rotor rotating speed in the interrupted power supply energy saving control process. The motor rotating speed accurate identification method after outage in interrupted power supply energy saving control is able to ensure that the residual voltage in the outage control process is not too low in attenuation and ensure the stable rotating speed of the motor and accurate detection with no need for changing operation parameters of the motor in the condition of reducing the energy consumption as possible.

Description

The accurate discrimination method of power-off rear motor rotating speed in discontinuous power supply Energy Saving Control

Technical field

The invention belongs to energy saving motor and control technical field, particularly relate in a kind of discontinuous power supply Energy Saving Control The accurate discrimination method of power-off rear motor rotating speed.

Background technology

Oil field equipment mostly is beam pumping unit both at home and abroad, when this type load of motor-driven, is taking out During oil machine upstroke, motor is generally in heavy duty, due to sucker rod and fluid column gravity during down stroke Effect, motor can enter underloading even generating operation mode.For this portative feature of periodicity gesture, existing Lot of documents, from different Energy saving mechanism angles, proposes and studies the multiple joint for pumping-unit motor system Can technology.In terms of these power-saving technologies are broadly divided into two from the method for operation, one is not change Beam-pumping unit jig frequency, realizes energy-conservation by improving motor operational efficiency and line power factor, including discontinuous power supply, Pressure regulating energy-saving, the conversion of star angle, capacitance compensation, high efficiency motor, linear electric motors etc.；Another kind is under surge well The situation such as liquid level and liquid supply rate, by controlling motor or using the modes such as difference in functionality motor, and then change is taken out Oil machine jig frequency reaches energy-conservation purpose, including multispeed electric machine, frequency control, super-high slip ratio motor, takes out.

Wherein discontinuous power supply technology has been widely used in oil field, and its design starting point is in generating district Territory deenergization, the control mode that electric zone switches on power realizes Energy Saving Control, its major control link and Its feature is as follows:

1) disconnecting motor power when positioned generating and light condition, now the winding voltage of motor, electric current are Zero, to greatest extent on reduce the loss of electric machine.Motor is allowed to continue when reentering electronic operating mode switching on power Reforwarding row.If able to rationally select power-cut time oil pumper disconnected in oil pumper one Machine cycle of work After electricity, motor utilizes oil pumper potential energy and inertia to continue to rotate, it is achieved that " power-off is not shut down " Energy Saving Control.

2) by detecting the operating rotating speed of motor after power-off, electronic operating mode is entered and to be in synchronous speed attached at motor Closely realize power supply by " quick soft input " control method to put into without impact, it is achieved that " energising is without impact " Controlling, energy-saving effect is notable.

Completing " power-off is not shut down, is energized without impact " " in controlling unit, in order to realize, " energising is without punching Hit " control, it is desirable to the power putting into the power supply moment is in non-heavy service state, and motor speed should be use up simultaneously Amount is close to synchronous speed.In order to realize putting into power supply near synchronous speed, the accurate detection of power-off rear motor rotating speed Particularly important.The inaccurate not only impact of detection puts into the dash current in moment, can cause pumpingh well under serious conditions Mechanical attachment fault is even shut down.Although existing pertinent literature proposes the side utilizing detection motor speed of taking part in a performance Method, but it is long not account for power-off time, the problem that motor speed cannot be detected after residual voltage decay is too small.

Summary of the invention

For the problem that the decay of the oil pumper mentioned in above-mentioned background technology long-time power-off residual voltage is too low, this Bright propose the power-off accurate discrimination method of rear motor rotating speed in a kind of discontinuous power supply Energy Saving Control, including:

After cutting off motor power supply, utilize motor stator winding residual voltage to detect rotating speed, treat that residual voltage decays During to rated voltage 10%, utilize machine controllable silicon device to be energized to any one phase winding of stator, make Obtain rotor bar and induce electromotive force and electric current；

After any one phase winding of stator is energized, the electric current relying on rotor-side to be induced produces in space Cutting stator winding is carried out in the raw magnetic field rotated with rotor, and induces the induction electric corresponding with rotor speed Gesture, by single-chip microcomputer judge induction electromotive force frequency can complete discontinuous power supply Energy Saving Control during rotor turn The accurate identification of speed.

The described condition voltage phase angle to be met to the energising of stator any one phase winding is 120 °～150 °, energising Time continues 5ms～10ms.

The accurate discrimination method of described rotor speed includes:

In power-off running, by comparator, residual voltage analogue signal is converted into square wave, recycles monolithic Machine external interrupt detects with time timer interrupt function and calculates adjacent two mistakes in stator winding residual voltage waveform Duration T between zero point_c, computing formula is as follows:

T_c=k × T₀

In formula, T_cRepresent one cycle duration of residual voltage；K represents timer interruption during twice external interrupt Number of times；T₀For each duration of interruption of intervalometer；

T detected_cAfter, motor speed can solve with following formula:

n_r=60/ (P × T_c)

In formula, n_rRotor speed for identification；P is motor number of pole-pairs.

Described residual voltage decay to rated voltage 10% moment can by detection residual voltage waveform obtain, to not Synperiodic residual voltage amplitude carries out exponential function matching and predicts, is calculated as follows:

U_res=U₀×e^-t/τ

In formula, U_resFor residual voltage amplitude；U₀Voltage magnitude for first cycle of detection residual voltage；T is the time； τ is damping time constant, is tried to achieve by curve matching.

The beneficial effects of the present invention is:

The accurate discrimination method of motor speed in power-off running proposed by the invention, it is possible to fit well Answering motor of oil extractor load complicated and changeable, no matter how load fluctuates, and the method for the invention can Accurately pick out motor speed when power-off runs；

Method proposed by the invention can not only accurately pick out motor speed, and can suitably slow down The motor speed sharply increased therewith during load release potential energy, prevents rotor from rotating too fast and damaging motor；

The method of the invention obtains good energy-saving effect not only by accurately judgement rotating speed, and Ensure that the normal table of motor runs；

The motor speed that the present invention is applicable not only in motor of oil extractor discontinuous power supply Energy Saving Control is accurately distinguished Know, it is also possible to the accurate identification of motor speed when power-off runs be applicable to other technologies.

Accompanying drawing explanation

Fig. 1 is Speed Identification method flow diagram of the present invention；

Fig. 2 is residual voltage waveform after 5.5kW motor of oil extractor power-off；

Fig. 3 is residual voltage waveform after 22kW motor of oil extractor power-off；

Fig. 4 is single-chip simulation signal revolution word signal hardware circuit diagram；

Fig. 5 is square wave schematic diagram residual voltage analogue signal changed in power-off running of the present invention；

Residual voltage analogue signal is changed into square-wave signal for the present invention in actual power-off running by Fig. 6 Oscillogram；

Fig. 7 is that single-chip microcomputer triggers signal hardware circuit diagram with output；

Fig. 8 is control machines loop circuit figure；

Fig. 9 is present invention winding voltage when any one phase winding of stator is energized and current waveform；

Figure 10 is that power-off 3s of the present invention is energized residual voltage waveform again；

Figure 11 is that the present invention is by the residual voltage waveform pass zero point motor speed that interval time, identification obtained.

Detailed description of the invention

Below in conjunction with the accompanying drawings, a 5.5kW motor and figure are described in detail embodiment and step, such as Fig. 1 Shown in,

(1) controlling device to detect whether to meet power operation, performing power operation if met；

(2) after power-off, first single-chip microcomputer detects motor winding residual voltage amplitude, the residual voltage waveform detected such as figure Shown in 2 and Fig. 3, it is residual voltage waveform after 5.5kW and 22kW motor of oil extractor power-off respectively；Detection residual voltage While also need to by residual voltage amplitude is fitted, anticipation winding residual voltage amplitude less than rated value 10% Time the possible moment；Such as utilize the residual voltage data of 5.5kW motor in subordinate list 1, use U_res=U₀*e^-t/τEnter Row matching, can obtain τ and be 3.8, can draw with primary Calculation and need about 7.8s when residual voltage amplitude is less than 10%； The residual voltage data of 22kW motor in subordinate list 2, use U_res=U₀*e^-t/τBeing fitted, can obtain τ is 0.34, Can draw with primary Calculation and need about 0.88s when residual voltage amplitude is less than 10%；

Table 1 5.5kW motor residual voltage amplitude changes over value

Table 2 22kW motor residual voltage amplitude changes over value

Time point	Amplitude
		1.167	466
1.187	434
		1.207	408
1.248	367
		1.268	346
1.288	327
		1.309	310
1.329	293
		1.349	278
1.37	262
		1.39	249

(3) when the residual voltage amplitude that sensor detects is more than 10%, use comparator shown in Fig. 4 by Fig. 5 Middle residual voltage analogue signal is converted into square wave, as shown in Figure 6, utilizes motor single-chip microcomputer external interrupt fixed with the time Time device interrupt function detect and calculate in stator winding residual voltage waveform the interval time between adjacent two zero crossings T_c, according to the residual voltage waveform pass zero point duration T detected_cThe motor speed picked out；

(4) when sensor detects that residual voltage decays to rated voltage 10%, utilize shown in Fig. 7 and Fig. 8 single Sheet machine controls silicon-controlled device detection voltage-phase, any one to stator when voltage phase angle is 120 °～150 ° Phase winding is energized, and conduction time continues 5ms～10ms, as it is shown in figure 9, t₁～t₂Moment is controlled silicon conducting district Between, curve thickened portion is respectively a phase winding voltage waveform and a phase winding current waveform, voltage in Fig. 9 Amplitude proportion reduces 20 times, and winding voltage and electric current then clearly can represent in the same coordinate system, after power-off again The residual voltage waveform of secondary of short duration energising as shown in Figure 10, detects residual voltage waveform mistake after the ofest short duration energising further Zero point duration T_c, according to T_cPicking out motor speed, subsequent step is by described in (3)；

(5) through above-mentioned steps (3) and (4), the motor speed detected is as shown in figure 11.

(6) detect and meet power on condition, use quick soft throwing technology to connect three phase mains.

This embodiment is only the present invention preferably detailed description of the invention, but protection scope of the present invention is not limited to In this, any those familiar with the art, in the technical scope that the invention discloses, can think easily The change arrived or replacement, all should contain within protection scope of the present invention.Therefore, the protection model of the present invention Enclose and be as the criterion with scope of the claims.

Claims (4)

1. the power-off accurate discrimination method of rear motor rotating speed in a discontinuous power supply Energy Saving Control, it is characterised in that Including:

After cutting off motor power supply, utilize motor stator winding residual voltage to detect rotating speed, treat that residual voltage decays During to rated voltage 10%, utilize machine controllable silicon device to be energized to any one phase winding of stator, make Obtain rotor bar and induce electromotive force and electric current；

After any one phase winding of stator is energized, the electric current relying on rotor-side to be induced produces in space Cutting stator winding is carried out in the raw magnetic field rotated with rotor, and induces the induction electric corresponding with rotor speed Gesture, by single-chip microcomputer judge induction electromotive force frequency can complete discontinuous power supply Energy Saving Control during rotor turn The accurate identification of speed.

Method the most according to claim 1, it is characterised in that described to the energising of stator any one phase winding Condition voltage phase angle to be met be 120 °～150 °, conduction time continue 5ms～10ms.

Method the most according to claim 1, it is characterised in that the accurate discrimination method of described rotor speed Including:

In power-off running, by comparator, residual voltage analogue signal is converted into square wave, recycles monolithic Machine external interrupt detects with time timer interrupt function and calculates adjacent two mistakes in stator winding residual voltage waveform Duration T between zero point_c, computing formula is as follows:

T_c=k × T₀

In formula, T_cRepresent one cycle duration of residual voltage；K represents timer interruption during twice external interrupt Number of times；T₀For each duration of interruption of intervalometer；

T detected_cAfter, motor speed can solve with following formula:

n_r=60/ (P × T_c)

In formula, n_rRotor speed for identification；P is motor number of pole-pairs.

Method the most according to claim 1, it is characterised in that described residual voltage decays to rated voltage 10% Moment can be obtained by detection residual voltage waveform, the residual voltage amplitude of different cycles is carried out exponential function matching and comes Prediction, is calculated as follows:

U_res=U₀×e^-t/τ

In formula, U_resFor residual voltage amplitude；U₀Voltage magnitude for first cycle of detection residual voltage；T is the time； τ is damping time constant, is tried to achieve by curve matching.