Along with micro electron, electric power electronic technology development, product manufacture technological level and natural price and so on high performance high efficiency semiconductor module compared to enhancement, IC chip function day by day formidable, the servocontrol function and the technology also in the unceasing consummation and the enhancement, its application domain more and more are also broad.

The time science and technology limited company has the omni-directional servo-control function by the independent intellectual property rights development exchange asynchronous machine servo controller. Its controlled member is the three phase ac asynchronous machine, enables the asynchronous machine the control precision to achieve the synchronized servo electrical machinery the level. Time exchange servo controller velocity modulation scope broad, pointing accuracy high, low speed torque big, the software function is perfect. Three phase ac asynchronous motor structure simple, price inexpensive, the movement is reliable, exempts the maintenance and the service life long merit enables the exchange asynchronous servosystem to have the good prospects for development, will become one of future servo-control technological development main directions.

In recent years our country used electricity the situation to be anxious, but took used the TV University household the oil field, it continuously stayed at a high level with the electric quantity. The pumping unit is the oil field uses most oil extraction equipment, at present the our country various oil fields in use the pumping unit has above 100,000, each Taiwan Telegraphic Transmission motive capacity generally all above 30kW, according to like this calculates, the general equipment department machine capacity above 3 million kW, is the oil field power consumption biggest equipment group.

2nd, pumping unit velocity modulation and energy conservation

Because the oil well well depth, the oil material, stick thickness, the silt content, the water content and so on various, the pumping unit operating mode, flushes the order, the stroke, the electrical machinery power is also various. The pumping unit product flushes a hypothesis generally in 6~8 /min, but the actual oil well flushes the inferior scope request in 1~12 /min. Needs to adjust the pumping unit according to the well situation change to flush the order, at present the oil field uses the means have several kinds:

(1) replaces the band wheel

This means shortcoming needs the engine off replacement, costs the time, affects the output. In lowly flushes in a situation, as a result of is initiative 带轮 small has been unable to realize or the efficiency reduces, some oil fields use the increase level leather belt transmission the method, increased the mechanical cost, the effect has not been good.

(2) uses 变极 two (3) fast electrical machinery, through changes the electrical machinery 极对�?the adjustment rotational speed

This means shortcoming is the electrical machinery speed change is the step leap -like, the impact is very big, also only has two or three fixed speeds, is unable to achieve the demand the speed, also is unable the low speed movement.

(3) uses the electromagnetism velocity modulation electrical machinery adjustment rotational speed

This means shortcoming is the electrical machinery when the low speed movement consumes energy with the labor frequency movement when same, efficiency low, is easy to give off heat. Outside the electromagnetism velocity modulation electrical machinery ill uses in the environment, is easy to damage.

(4) uses the frequency changer to control the electrical machinery velocity modulation

This means shortcoming is as a result of the frequency changer own weakness, when low frequency outputs the torque to have the drop, the low speed load characteristics is bad.

The pumping unit enhances the efficiency, the frugal electrical energy way, besides makes the issue in the itself mechanism, is carries on the transformation promotion to the electrical machinery system. To electrical machinery control system basic request: Can the wide range stable velocity modulation, have the remarkable electricity saving effect. The time science and technology limited company used the exchange asynchronous servo controller which oneself produced to make the oil field pumping unit special-purpose velocity modulation, the energy conservation servo-control cabinet, in the area south of Yellow River, the victory oil field use, and passed through the test. This control cabinet has overcome above several kind of velocity modulation method shortcoming, had achieved good, the simple velocity modulation request, the electricity saving effect extremely is also obvious. The attached figure shows for the time science and technology exchange servo-control cabinet and the ordinary asynchronous machine in the oil field pumping unit application actual outline drawing.

3rd, the pumping unit electrical machinery uses the servo-control the superiority

3.1 velocity modulation scopes are big

The wide range control speed is one of servo-control basic functions, the oil field pumping unit exchange asynchronous machine uses the servo-control, may accurately control the electrical machinery the rotational speed, achieved adjusts the pumping unit to flush a goal. The time exchange servo controller has the permanent torque input level in zero to the rated speed scope in, some three time of nominal torque overload capacity, therefore under the very low output frequency, the electrical machinery outputs the torque, has sufficiently satisfied the pumping unit load request.

3.2 low speed big torque control characteristic

The time exchange servo controller has the low speed big torque the control characteristic, starts in the pumping unit electrical machinery in the process, the controller may actuate the electrical machinery to output the enough torque, the rotational speed from 0 rises to supposes the definite value, the electric current is steady, realizes the true soft start. In shoulders a lighter oil well, in �?admits defeat in the start foundation, through the test, confirmed definitely may use to compare the low power the electrical machinery substitution original electrical machinery, achieves the further energy conservation.

3.3 may to the electrical machinery output torque realization different control mode

Flushes in the order in a pumping unit oil pumping, as a result of 平衡�?and the potential energy load influence, the electrical machinery two time is at the electricity generation condition. The electrical machinery electric current change showed its load moment in pulls out between the painter's shop merit and the potential energy load rapid change. According to the torque change rule analysis, internal PLC function which has using the time exchange servo controller, has established the pumping unit operating procedure, exchanges drives the kerosene engine torque to carry on the monitor, according to the torque change tendency, the servo controller may to the electrical machinery output torque realization different control mode, achieve the electricity saving the goal. As a result of the speed and the torque may 解�, separately control, the servo controller has adopted under on the slow quick speed control regarding the oil pumping stroke, enhanced the oil mass.

3.4 uses hands over - is straight - hands over the frequency conversion main circuit

The time exchange servo controller uses hands over - the straight - alternation frequency velocity modulation main circuit, the direct current side and has the large capacity electric capacity, thus greatly enhanced the electrical machinery system power factor, reduced the idle current, also saves part of electric powers expenditures.

3.5 lowly is flushing on the pumping unit which, needs to modulate velocity to use the servo-control to have three superiority

(1) 极对�?compares with the replacement belt pulley and the change electrical machinery, velocity modulation method simple, convenient, the velocity modulation, is continuously smooth, does not have the impact.
(2) compares with the frequency changer control electrical machinery, velocity modulation scope wide, low speed torque performance good, the load capacity is big.
(3) and the electromagnetism velocity modulation electrical machinery compared to, the servo-control ordinary asynchronous machine electricity saving effect is obvious. According to the formula, torque T maintains invariablely, when rotational speed n reduces, output P also correspondingly reduces. Electrical machinery rotational speed lower, the consumption electric power are less. But electromagnetism velocity modulation electrical machinery no matter the rotational speed is how many, power P basic is invariable.