Case Study: Shanghai Zhenhua Heavy Industry Co. Ltd. achieves precise 3000-tonne crane control with Danfoss VACON AC drives

Controlling a 3000t slew crane on Chinese offshore pipe-laying vessel

Shanghai Zhenhua Heavy Industry Co. Ltd. (ZPMC), a leader in heavy-duty offshore equipment, needed a reliable drive and control solution for its new 3000-tonne derrick pipe-laying vessel and 360° slew crane. The challenge was to manage extremely high loads and precise motion control for offshore hoisting and pipe-laying operations, while meeting marine classification requirements and ensuring dependable performance in a demanding environment. Danfoss, through its VACON® AC drives, was selected after technical evaluations for its proven reliability, open software platform, and shipbuilding experience.

Danfoss implemented a modular common DC bus drive system using 4 VACON® NX rectifiers, 17 VACON® NXP inverters, and 2 braking units to control all crane actuators. The solution delivered highly accurate speed and torque control, including full torque at zero speed, and kept total harmonic distortion below 5%, satisfying marine standards. As a result, ZPMC’s vessel can hoist 3000 tonnes stationary, 2000 tonnes while slewing, and lay two pipelines simultaneously, with the success of the project leading to further crane applications on other barges.

Shanghai Zhenhua Heavy Industry Co. Ltd