The application of large load steps to the power system of an all-electric ship raises power quality
issues since sudden changes in electrical loading on synchronous generators can cause their output
frequency to fluctuate widely as the prime mover adjusts to meet the demand. This paper explores three
control strategies for minimizing the fluctuations of generator frequency during load-step disturbances.
These strategies include reducing propulsion motor power demand, accessing propulsion motor
regenerative power, and applying regenerative power from a dedicated capacitor energy storage device to the generator bus. The performance of each control strategy was examined using a large-scale, real-time digital simulation model of a notional ship system. The simulation results demonstrate the control
strategies’ effectiveness in eliminating load-step frequency disturbances as well as limiting their
magnitude to the level of military standards for shipboard systems.
M. Andrus and Dr. M. Steurer, In Proc. ASNE Automation & Controls Symposium, Biloxi, MS, December 10-11, 2007
KEYWORDS: IPS, energy storage, shipboard power systems, modeling and simulation, load steps, RTDS