Reference:
H. Hellendoorn,
S. Mulder, and
B. De Schutter,
"Hybrid control of container cranes," Proceedings of the 18th IFAC
World Congress, Milan, Italy, pp. 9697-9702, Aug.-Sept. 2011.
Abstract:
Hybrid cranes use ultracapacitors to store energy that is regenerated
when lowering a container or during braking, and reuses this energy to
assist the engine later on. A hybrid crane needs a system that
optimizes the fuel cost by controlling in real time the two available
power sources. Currently, the crane uses a rule-based heuristic
strategy, which does not achieve optimal results and is difficult to
tune. An alternative approach is Equivalent Consumption Minimization
Strategy (ECMS), an optimization-based strategy of limited complexity
that assigns a weight to the usage of the ultracapacitors that
represents the equivalent 'future fuel cost'. Two new strategies are
presented that each have their own approach to this issue. The first
uses feedback from the state of the ultracapacitors, the second uses
predictions about the upcoming power demand. The new strategies are
compared with the current system. The new strategies consistently
outperform the current system, significantly improve the fuel savings,
and increase the operational profits.