Permanent Magnet Direct-Drive Pumping System with Regenerative Energy Recovery: A Hybrid BESS-Integrated Topology for Grid Power Stabilization

Oilfield pumping units, as typical loads with periodic forward/reverse rotation, generate substantial regenerative energy during braking. Traditional drive systems dissipate this energy via braking resistors (causing waste) and fail to mitigate grid power fluctuations induced by load periodicity—two critical issues against the “dual-carbon” goals. To address these, this paper proposes a grid-connected energy management architecture based on a common AC bus for permanent magnet direct-drive pumping systems. The architecture integrates the utility grid, a battery energy storage system (BESS), and multiple independent motor drive units, with the AC bus serving as a centralized power hub to eliminate redundant energy conversion stages (a flaw of traditional DC bus schemes). By combining multilevel converters, vector control, and a grid-power-smoothing energy management strategy, the system enables unified dispatch of bidirectional power flow: during the pumping unit’s upstroke (power absorption), the grid supplies base power; during the downstroke (regenerative energy release), the BESS absorbs excess energy instead of feeding it directly to the grid. Simulation results (via MATLAB/Simulink) verify three core objectives: (1) high-precision torque/speed control of motors (tracking 100 Nm upstroke torque and 80 Nm downstroke torque); (2) efficient regenerative energy recovery (bidirectional power flow between motors and the AC bus); (3) stable grid power output (fluctuation rate ≈0.65%). This topology provides a low-cost, high-efficiency solution for energy conservation in oilfields and grid stabilization under periodic loads.