Power Balance Strategy for Hoist Motors of Twin-Trolley Quayside Crane Based on Torque Master-Slave Control

When the hoist mechanism of a twin-trolley quayside crane uses dual motors with rigid shafts to drive the same drum, differences in motor parameters tend to cause uneven power distribution. A power balance strategy based on torque master-slave control with torque-difference feedback is proposed. The master motor adopts speed-torque dual closed-loop vector control, while the slave motor tracks the master torque in torque control mode. To improve dynamic power balance accuracy, a torque-difference feedback loop is introduced to dynamically compensate the slave torque command. A simulation model is built in MATLAB/Simulink and verified under both motoring and regenerative braking conditions. Results show that the proposed strategy achieves steady-state torque deviation within 1%, dynamic power imbalance within 5%, and regenerative imbalance down to 2.8%.