OVERVIEW OF PROSPECTIVE DIRECTIONS FOR IMPROVING THE DYNAMIC CHARACTERISTICS OF VESSEL ELECTRICAL ENERGY SYSTEMS

Abstract

Introduction. The work presents a brief history of the emergence and development of electric ships in the global maritime industry and emphasizes their growing role in our time, which is the result of using those advantages that are characteristic of ships with electric propulsion – environmental friendliness, economy, better operational and dynamic characteristics, etc. Based on the given generalized scheme of the combined electric power system of the electrically driven and its main components, the main factors affecting the change in the characteristics of ship electric power systems (SEPS) during dynamic loads are determined. On the other hand, the local regulators of the constituent parts of the SEPS – the automatic regulator of the rotation frequency of the primary engines, the automatic regulator of the voltage of the generators, the controller of the frequency converter are adjusted in such a way as to ensure the optimal functioning of their regulatory objects mainly in static modes of operation. The next step in the development of automatic control systems (ACS) of the SEPS is the implementation of multi-level systems with their own control strategies, which allows to bring the operational characteristics of ship propulsion systems into compliance with the requirements of classification societies for the parameters of electrical networks during transient processes, which are also given in the article. Numerous studies and proposals for solving such tasks, the number of cited sources and the wide range of issues highlighted in them, allow us to assert that the development and improvement of SEPS for vessels with electric propulsion, as well as their regulators and control systems, will remain relevant for a long time. Purpose. An overview of the available directions for the development of the EPS of vessels with a electric propulsion plants as a whole, parts of these systems, control systems and analysis of such directions for improving the dynamic characteristics of both the systems themselves and their regulators. Results. According to the results of the review, among the main trends that determine the development of electric rowing vessels SEPS, we can mention the use of new energy sources, an increase in the total power of installations and the energy density of their individual components as well, the appearance of powerful short-term impulse loads, the abandonment of electromechanical automation units in favor of electronic devices. On the other hand, the problems of exchange oscillations in multi-unit ship power plants, accidental shutdowns of SEPS during dynamic processes, deterioration of the quality of electricity in ship power networks due to the presence of higher harmonic components caused by the use of powerful static semiconductor converters, are still waiting for their final solution. When modeling dynamic modes, some sources use mathematical models with linearized equations, without taking into account nonlinearities, the properties of which SEPS elements acquire during dynamic loads. Models with single generating units are also used, while the influence of exchange fluctuations is neglected. It was not possible to find studies devoted to the response of automatic regulators to changes in the condition of primary engines due to failures and malfunctions. Most of the proposed ways of improving dynamic characteristics are material- and labor-intensive, require significant periods of time for implementation, and are suitable for promising types of electric vessels. Conclusions. According to the authors of the studied articles, there are a number of problems for electric ships SEPS that arise during dynamic processes. In order to solve them, it is necessary to develop a mathematical model of the SEPS, taking into account the nonlinear properties of the parts of the system that appear in transient modes. After checking and conducting an experiment with the model, it is necessary to develop an adaptive regulator with the inclusion of one of the input signals that would reflect the technical condition of the primary engine. The creation of such a regulator will allow ships with electric propulsion to optimally undergo dynamic disturbances according to the criteria of safety, economy and energy efficiency.