Modeling and Control of a DC-grid Hybrid Power System with Battery and Variable Speed Diesel Generators

Abstract

Hybrid electric power systems (HPS) have successfully been integrated in the road-traffic industry due to enhanced efficiency and environmental benefits. Recently this concept has been implemented in the marine sector. In this master thesis, the construction of a DC hybrid power system for a marine vessel is outlined in detail. The HPS is developed in Matlbat/Simulink and comprises two set of diesel generators with variable speed, six-pulse diode bridges, a battery bank, bidirectional converter and a constant power load (CPL). The associated controllers which are designed includes battery controller, engine speed controller and voltage-exciter controllers. An emphasized focus will lay on structures of voltage-exciter controllers. For this purpose, control structures for operation of generator set alone or together with the battery are investigated. The performance of all controllers are tested for a specific test-bench. In addition to this, specific fuel-oil consumption (SFOC) of the diesel engine will be evaluated through an implemented SFOC-model, where SFOC for operation both with and without battery is compared.