| Beam pumping unit is used universally in oil exploitation. But some problems are existent in its traction system, including: Low fullness degree of pump and serious"big horse hauling small cart"result in low motor efficiency and low power factor; Load fluctuates tempestuously, and motor's regenerating electricity causes concussion of energy feedback. To solve the above problems, the paper investigates and develops a kind of frequency conversion control system based on DSP especially for beam pumping unit, improving oil recovery and energy-saving efficiency.Based on analysis, sum-up and comparison of manifold control ways, frequency conversion control system focusing on high performance DSP TMS320LF2407A is brought forward. The system mainly includes AC-DC-AC frequency conversion main circuit, detection and protection controlling unit, DSP controlling system, running status display unit and driving unit, and so on. Through automatic detection and synthetic analysis of motor's load parameters, dynamic load tracking and optimal control, and separate stroke frequency control are brought into use, ameliorating motor's running status, improving energy-saving efficiency, and obtaining prominent effect of saving energy and increasing output. Aimed at motor's vibration problem at low frequency as SPWM carrier frequency increases, through abundant principle research and experiments, the causation is digged out, and a practical predigested scheme of PWM control is put forward. In system protection, aimed at extensive fluctuation of AC power network, separate voltage protection circuits of AC and DC are realized. The scheme is proved to be feasible and reliable by locale experiments and detecting outcome.Routine PWM reversible rectifier requires high DC voltage and complicated control. Considering the performance requirement of lopsided energy feedback, the paper tentatively advances a converse commutating PWM control scheme. The scheme is proved to be feasible by simulation and experiment.
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