Let’s introduce the new and smart plug-in hybrid power system which will be finally installed in the research & training vessel ORTZE as result of the R&D activities that are being done under the ORTZE-CV project.
Figure. Layout of the ORTZE-CV new plug-in hybrid integrated power system.
Two power electronics based Multidrive (Multi-Converter) systems will be the heart of the new and smart Integrated Power System for the ORTZE research & training vessel.
A high energy efficiency dual winding electric motor based on the permanent magnet synchronous machine technology will drive the main propeller of the vessel. This electric motor will be controlled from two inverters, one installed on the ‘Stern Multidrive’ and the other on the ‘Starboard Multidrive’. The electric power is distributed along a DC distribution system which can be powered from: (1) The Genset through an Active Front End Rectifier (AFE) installed on the ‘Stern Multidrive’, and/or (2) The energy storage system (batteries) through a DC/DC converter installed on the ‘Starboard Multidrive’.
The DC distribution system allows the operation with the DC bus-tie breaker protection device open or closed. Consequently both power system zones (the one fed by the Genset and the other by the Energy Storage System) can be operated individually, independently or simultaneously, thus obtaining a high level of operability, redundancy and safety. As an example, in case of a severe short circuit or fault in one zone, the DC bus-tie breaker will isolate the faulty zone very fast (avoiding the blackout) thus ensuring the operation from the other zone at least with the half of the power.
Two AC distribution systems (at constant voltage & frequency) are generated from both Multidrives to supply other vessel loads (auxiliaries, hotel loads, etc.). They can be also operated individually, independently or simultaneously thanks to the AC bus-tie breaker protection device. The Multidrives controllers allow the operation of both AC distributions simultaneously (when the AC bus-tie is closed) by ensuring their synchronization and the load sharing operation. The power supply for the rest of the vessel loads is then ensured too with a high level of redundancy.
The energy management strategy (and then the reconfiguration of the power system) can be selected manually by the vessel crew based on the energy state of the different power sources (the energy states are continuously displayed on the HMI). Smart and secure power limits and mode transitions, programmed internally on the own Multidrives controllers, correct the possible mistakes on the energy strategy defined by the crew. On the other hand, an energy management function programmed on the automation system can assist the crew for supporting the decision making of the best operation mode in terms of energy efficiency and emissions reduction. This smart function will consider the actual power consumption, the expected power profile of the vessel mission and the actual energy states of the different power sources in order to advise the crew on the best energy strategy.
To finalize this brief introduction let’s talk about its functionality and operability. The new integrated power system will be highly reconfigurable allowing different operation modes. The reconfiguration of the power system can be selected & performed on demand by the crew, or automatically by the coordinated Multidrives protection & supervision systems. Four different operation modes will be available depending on the state of the power sources: (1) The fully electric zero emissions mode (Genset switched off), to be used mainly near the coast or when sailing over environmentally protected areas at low speeds (low loading), (2) The diesel-electric mode (Batteries switched off), to be used mainly when the battery system is not available, (3) The hybrid mode (Batteries and Genset switched-on running together in a coordinated and efficient way guided from the power & energy control system), to be used mainly far from the coast particularly when high power consumption are required, and (4) Harbouring with shore electrical connection operation mode (Genset switched off) to be used for recharging the batteries and for supplying the hotel loads from the shore power grid when in harbour.
By Juanjo Valera