Dynamic Simulation of Flywheel Energy Storage Beam Pumping Unit System and Adaptive Frequency Conversion Voltage Regulation Energy-Saving Optimization

Abstract

Installing a flywheel energy storage device in a beam pumping unit can effectively suppress fluctuations in the motor speed and output power of the pumping unit, reduce its peak power, improve efficiency, and lower the installed power capacity. However, while influencing the motor speed, the flywheel energy storage device indirectly affects the motion law and loading conditions of the pumping unit, and its impact varies with different equipment models. This renders the original pumping unit stroke frequency controller inadequate for the new system. By analyzing the motion and load characteristics of the pumping unit, this paper proposes an adaptive frequency conversion and voltage regulation control technology based on fuzzy PID and frequency converters. This technology alters the operating state of the pumping unit by adjusting the motor frequency. Its main features include: 1) Deriving an optimized frequency curve under constant stroke frequency conditions using a pumping unit frequency conversion optimization algorithm. 2) Indirectly modifying the acceleration at the polished rod to reduce dynamic loads through frequency conversion. 3) Utilizing the adaptive adjustment capability of fuzzy PID to eliminate the delay effect of the flywheel energy storage device on motor speed changes. A theoretical and simulation analysis was conducted using a CYJ10 model pumping unit and a flywheel energy storage system with a moment of inertia of 5 kg·m² as a case study. The energy-saving control effect was compared through simulation and measurement. The results indicate that the established simulation model has high accuracy and is referential. Adaptive frequency optimization control can significantly improve the dynamic performance of the new pumping unit system, notably reducing the polished rod load, increasing the motor load factor, decreasing the average power consumption, resulting in an overall system energy saving rate of 12%.