New software from GE’s Power Conversion business that enables its Dynamic Positioning (DP) systems to save significant amounts of fuel and put less wear and tear on vessel propulsion equipment is on the shortlist to win an Institution of Engineering and Technology (IET) Innovation Award this year.
A DP system holds a vessel in position without the aid of anchors, using only propellers, rudders and thrusters. “Energy Efficient Dynamic Positioning For Ships” was developed from a comparison of concepts through to final production code using model-based design. The new mode was entered in the Model-Based Engineering category for the IET Innovation Awards, which attracted more than 400 entries. The awards will be announced in London on November 20.
During development of the new Energy Efficient DP, experts at GE Power Conversion used model-based engineering to allow the production controller to be used in simulations to ensure accurate results. Studies making use of weather patterns for a full year showed that a 12 percent reduction in fuel usage could be expected for representative scenarios. At the same time, the wear in terms of stick-slip cycles on the thrusters and propulsion system could be reduced by a factor of 10 or more over the same period.
DP normally aims to maintain the position of the vessel at a single defined point. This leads to constant corrections by the thrusters as the vessel makes small motions about this point. The energy efficient mode allows the operator to define an aim circle within which the vessel is permitted to move. A novel predictive control algorithm predicts future motion and only updates the thrust demands if the vessel is predicted to move close to or outside the permitted area. Far fewer small corrections are made, reducing fuel consumption, emissions and equipment maintenance requirements.
The new mode is now available for sale to customers in the form of software upgrades to existing DP systems. The predictive algorithm is not very computer intensive, making it possible to use it in most existing controllers without hardware changes.