Adaptive permanent magnet brushless DC motor macrocontrol system for beam-pumping unit
A permanent magnet brushless DC, beam-type pumping unit technology, applied in the direction of a single motor speed/torque control, electronic commutator, etc., can solve the problem of large motor starting current, low motor efficiency and power factor, Malaysia Pull the trolley and other problems to achieve the effect of good matching, reduced energy consumption, and reduced stroke loss
Active Publication Date: 2012-12-26
沈阳永磁电机制造有限公司
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Problems solved by technology
This brings about a series of problems that the power source does not match the load characteristics
The starting torque of the 3-phase cage asynchronous motor is about 2 times of its rated torque. Therefore, when selecting the motor capacity of the pumping unit, it is not based on the equivalent output power as the criterion, but on the premise of satisfying the starting torque. This has created the phenomenon of "big horse-drawn carts"
Therefore, the starting current of the motor is very large, and the motor works at a low load rate, causing the motor to work in a working state with low efficiency and power factor
The slip rate of the 3-phase cage general-purpose asynchronous motor is within about 5%, and its mechanical characteristics are very hard, which causes a mismatch between the power source and the load and reduces the system efficiency
[0004] In order to reduce energy consumption per unit liquid production and increase oil production, various types of motors have been researched and tested at home and abroad, such as: high-slip and ultra-high-slip 3-phase cage asynchronous motors, frequency conversion speed regulation 3-phase cage Asynchronous motor, 3-phase cage-shaped asynchronous motor with electromagnetic clutch, 3-phase wire-wound rotor asynchronous motor, rare earth permanent magnet synchronous motor, switched reluctance motor, etc., the experimental results are not ideal enough
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[0018] The present invention will be described in detail below with reference to the accompanying drawings.
[0019] The motion law of the beam pumping unit can be approximated as the simple harmonic motion that the crank connecting rod transforms the motor's rotational motion into the sucker rod's simple harmonic motion. Therefore, the linear position S of the suspension point of the pumping unit A , moving speed V A , acceleration a A Both are functions of the crankshaft angle θ.
[0020] S A =a / b r( 1-cosθ )
[0021] V A =a / b·r·Ω·sinθ
[0022] a A = a / b r Ω 2 ·cosθ
[0023] In the formula, a, b, r, θ see figure 1 ;Ω is crank angular velocity, rad / s
[0024] When θ = 0, S A =0, which means that the suspension point A is at the lowest point, that is, the piston of the oil well pump is at the lowest point, which is the end point of the downstroke and the start point of the upstroke. When θ=180°, S A =2a·r / b is equivalen...
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The invention discloses an adaptive permanent magnet brushless DC motor macrocontrol system for a beam-pumping unit, and relates to a motor control system for the beam-pumping unit. The adaptive permanent magnet brushless DC motor macrocontrol system consists of a permanent magnet brushless DC motor, a rotor position sensor and a controller. The control system performs control by taking the time t<*>=60N, s of each frequency of stroke of the pumping unit as instruction time and a sampling period; in the sampling period t<*>, the average revolution per minute n-iN of the motor is determined as a control target; and in the time t<*>, an operating point of the motor slides on a sagging mechanical characteristic curve determined by a pulse width modulation (PWM) duty ratio D along the change of load torque, thereby creating conditions for reducing stroke loss and making the motor always work in a high efficiency area. Compared with a three-phase squirrel cage asynchronous motor, the control system can reduce about 30 percent of energy consumed by the beam-pumping unit in the production of each ton meter of liquid.
Description
technical field [0001] The invention relates to a motor control system for a beam pumping unit, in particular to a macroscopic self-adaptive control system for a permanent magnet brushless DC motor for a beam pumping unit, which belongs to a macroscopically stable control system with closed-loop control of motor speed and irregular load changes. speed control technology. Background technique [0002] Beam pumping units account for more than 70% of mechanical oil production equipment. When starting the beam pumping unit, the motor needs to output a large starting torque in order to accelerate the pumping unit system including the balance weight. The load of each stroke of the beam pumping unit may be different, and the load torque changes all the time during a stroke. [0003] For a long time, most beam pumping units have been powered by general-purpose 3-phase cage asynchronous motors (such as Y series asynchronous motors). This brings about a series of problems that the...
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IPC IPC(8): H02P6/08H02P6/16
Inventor 鲍志民刘晨
Owner 沈阳永磁电机制造有限公司