OPTIMAL CONTROL PROBLEM OF A SHIP PROPULSION DIESEL-ELECTRIC SYSTEM

Abstract

The work is dedicated to solving the complex scientific and technical problem of increasing the energy efficiency of modern vessels equipped with diesel-electric propulsion systems. In conditions of strict regulation of greenhouse gas emissions and harmful substances (in accordance with the requirements of IMO MARPOL, EEDI, and EEOI) and the instability of world energy prices, the issue of optimizing ship propulsion system control is becoming critical. During the research, a review of modern publications on the topic of solving these problems was conducted. The researchers propose to use genetic algorithms, dynamic programming, and stochastic methods. The evolution of optimization methods is also reviewed: from strategies to minimize equivalent consumption to control systems based on predictive models. Special attention is devoted to the limitations of existing optimization methods, as many proposed approaches exhibit a critical disadvantage: they are either too simplified (static power balance models that ignore transients) or too complex to be implemented in on-board controllers. It is also found that a comprehensive formulation of the problem, which would combine the ship’s propulsion subsystem (with the dependence of resistance on the sea state), the generation subsystem (with nonlinear consumption characteristics of diesel engines), and the energy distribution subsystem in a single state space, remains insufficiently developed. Moreover, the designs of modern propulsion systems are analyzed using the example of a diesel-electric propulsion system, and a structural diagram and dynamic model of the system are built. The principles of operation of a DC motor for a diesel-electric propulsion system, and the profits of using it on marine vessels, are considered. The research focused on the scientific substantiation and mathematical formulation of energy-saving optimal control for a diesel-electric propulsion system. It is concluded that one of the ways to optimize the energy efficiency of a diesel power plant is to improve the quality of control of energy transfer from the diesel engine to the propeller. A method for constructing an optimal control algorithm based on the criterion of minimal energy losses in all elements of a diesel power plant along the conversion path is considered.