In early 2017, Eekels Technology started to develop a future-proof – low-emission – Modular Propulsion Platform (Marpower MPP) targeting the Sustainable Development Goals of the United Nations. With the MPP, shipowners have a wide range of opportunities for power modification during the lifecycle of the vessel.
This article appeared in SWZ|Maritime’s March 2023 energy transition special. It was written by Marvin de Haan, Manager Power Systems at Marpower, firstname.lastname@example.org, Ulco Hoekstra, Manager Sales BU Marine & Offshore at Eekels Technology BV, email@example.com, and Arnold Striper, Cluster Manager Marine Automation at Marpower, firstname.lastname@example.org. To view a larger version of the pictures in the article below, please right click on the image and select open in new tab. All pictures by Eekels Technology.
A conflict of challenges arises when it comes to new fuels, infrastructure, storage, safety, serviceability, investments and lack of regulations to meet the zero-emission goals. The flexible configuration and modular design of the MPP concept fills the gap in the energy transition to achieve the zero-emission roadmap to green shipping.
It also facilitates shipowners with a platform to convert and expand the electric possibilities in the future to new carbon-free fuels without high investments or changing the propulsion concept. The highly compact and modular design of the MPP in relation to the purpose of the vessel and its operational profile, gives the naval architect more opportunities and flexibility to develop an efficient hull design, a hybrid or fully electric propulsion line and to appoint the equipment in the vessel in a very efficient way to create more cargo volume and simplifying the engine room.
Ready for sustainable power sources
The Marpower MPP platform is capable of adapting to a combination of all kinds of different (electricity generating) power solutions on a direct current (DC) or alternating current (AC) platform, such as:
- battery technologies,
- redox flow batteries,
- super caps,
- heat recovery systems,
- wind assistance solutions,
- solar systems,
- dual-fuel generators, fixed or variable speed, and
- fuel cell technology – methanol, hydrogen.
The Marpower smart and high speed Automation Platform, that is, its energy management system, controls the power dynamics of all these different characteristics of power sources in an efficient way.
As an independent system integrator, Eekels Technology co-operates with innovative partners, shipowners, naval architects, knowledge centres and technology suppliers focusing on new carbon-free fuel solutions.
For the Vertom Labrax 7000 series, of which Thecla Bodewes Shipyards will build eight for Vertom Group, the MPP is designed for diesel-electric propulsion and ready for future upgrades. In order to save fuel and operate the diesel generators as efficiently as possible, operating with a closed bus-tie is preferable.
The system design is not only for operating the vessel at the design speed, but it also allows slow steaming in different ballast conditions. Slow steaming with one generator online in light duty mode is possible. Smart operation of four variable speed generators on 50 and/or 60 Hz in parallel makes the propulsion line more efficient in all weather and ballast conditions.
Modelling fuel consumption and all losses in critical systems like engines, generators, cabling, drives, gearbox, and propellers in different conditions is inevitable and a close co-operation with all involved partners and manufacturers gives an optimal result.
The Marpower Drive Management System controls the variable frequency drive (VFD) to optimise fuel consumption or to mitigate thruster “ventilation” in heavy weather. This feature is also usable for wind assistance appliances.
Easy upgrades and built-in redundancy
The Marpower MPP delivers unmatched efficiency, utilising cutting-edge power electronics technology to regulate power in and output. The modular design of the platform offers unparalleled flexibility and allows easy upgrades and maintenance. In addition, the platform features built-in redundancy, ensuring reliable and safe operation for the vessel.
The Marpower Configure To Order method provides customised solutions to meet the specific requirements of each client’s ship. Eekels Technology will work with the client and naval architects to understand their needs, including factors such as ship propulsion, operating conditions, class requirements and desired performance.
Standardised building blocks to configure the most optimal electric propulsion topology for the ship are used. The use of standardised blocks allows for a more streamlined and efficient solution during the development process. These blocks have been extensively tested and proven to deliver reliable and efficient performance, ensuring that the final solution for a vessel meets the highest standards of quality. This tailored approach will result in lower operating costs, increased reliability and improved safety.
For the Vertom Labrax 7000 series, a new set of standardised blocks was created based on the state-of-the-art iC7 range from Danfoss. The iC7 range consists of power electronic modules with a groundbreaking power density, enabling the creation of compact MPP blocks based on Eekels’ in-house manufactured panels optimised for iC7 hardware with the following standard functions:
- Motor Drive Control of electric motors (for example permanent magnet (PM) or induction machine (IM)),
- Active Front End: Control of power sources (for example PM generator, power take off (PTO)/power take in (PTI)),
- μGrid: Creating island or parallel grids from DC,
- DC/DC: Control of energy storage and DC supplies, such as batteries, fuel cells, super caps, and so on.
DC main switchboard features
The MPP for the Vertom Patty has several defining features:
- Footprint: The mechanical basic design using the MPP blocks results in a back-2-back panel design most suitable for the available space. Compared to an AC main switchboard set-up with separately placed 6-pulse or active front end (AFE) drives, the footprint is more compact, there are fewer cabinets and installation and construction work is reduced. The compact MPP results in the design seen in the picture at the top right.
- DC-bus and variable speed generators: The Marpower DC-bus technology enables the use of variable speed generators in combination with passive water-cooled rectifiers with controllable load-sharing for a compact flexible design. The design choice enables easy future expansion with battery systems for enhanced energy management functions. The standardised internal DC-bus layout is capable of handling large short circuit currents, making it suitable for systems with large internal capacitance and the typical challenges of the energy transition.
- Efficiency and cooling: The system’s design with passive water-cooled rectifiers and high-end power modules has a high overall efficiency with typical efficiency ratings of 99 per cent per module. Overall system performance is optimised by means of the Drive Management System (DMS). The inevitable losses are efficiently cooled to the closed internal “water” cooling system resulting in minimal losses to ambient and strain on the heating, ventilation, and air conditioning (HVAC) system. The inhouse designed water-cooling assembly consists of a stainless steel system with redundant pumps and heat-exchangers. The system has temperature and flow control to optimise cooling performance and integrated heaters to climate control and prevent condensation when the system is not used.
- Modular power stacks and redundant design: The iC7 platform in combination with the panel design ensures that servicing the panel in case of a failure is relatively easy. Power stacks can be removed without dismantling the cooling system in manageable blocks both in weight and size.
- The split bus design offers redundancy ensuring that propulsion power and the μGrid are always available, even during service. For the Vertom Labrax 7000, redundancy in propulsion is achieved by two electric motors connected to a single gearbox. If only one e-motor is available, still fifty per cent input power is available to the gearbox. Furthermore, each generator can be used to recover from a deadship situation, the DC-bus can be charged from each individual generator and the system is capable of charging across the no-load bus-tie from DC-bus 1 to DC-bus 2 and vice versa. In case of a future expansion with a battery system, there are even more options to recover.
The vessel is equipped with the Marpower Automation Platform, a modular automation system that can be tailored to the vessel’s operational profile. The integrated platform utilises different functions on the vessel. The main functions comprise of the alarm, monitoring and control system (AMCS), the drive management system (DMS), the energy management system (EMS), the propulsion control system (PCS), and the vessel performance system (VPS).
These systems work independently according to class regulations, but are integrated into one Automation Platform, providing the crew with one integrated user interface for monitoring and controlling the entire vessel. Using one integrated platform also reduces the amount of needed spare parts.
Alarm, monitoring and control system
The Automation Platform performs the vessel’s basic AMCS functionality. Because of its multi-redundancy design, it provides high availability. The screens display a modern, user-friendly user interface and the control take over (CTO) mechanism ensures control is only prohibited where it is needed. Next to standard alarm and monitoring functionalities, such as system health monitoring, alarm handling, trending and data
logging, it also provides pump and valve control and tank sounding functionality. The AMCS comes with a cyber-secured remote support interface, allowing for remote diagnostics and problem solving when needed.
Drive management system
The DC main switchboard is equipped with a DMS for monitoring and controlling every aspect of the switchboard. The basic layout is based on a “half-ship” design. Ensuring propulsion will stay up and running with one side of the switchboard and one motor even if the other side of the switchboard or motor has major issues. The system is built up with two programmable logic controllers (PLCs) and two screens as user interface.
The DMS of the DC switchboard monitors and controls the water cooling circuits, the motor drives, the μGrids, the generators’ automatic voltage regulators (AVRs), the interface to the AMCS, the interface to the EMS and the interface to the PCS.
Additionally, the DMS features a design consistent with the look and feel of the other components of the Automation Platform, ensuring seamless integration and a familiar user experience.
Energy management system
The EMS is responsible for handling the electrical power distribution of the vessel. The EMS performs basic power management tasks such as opening and closing circuit breakers, starting and stopping diesel generators and switching diesel generators between 50 and 60 Hz. Also, more advanced tasks are performed, such as load sharing, bus tie monitoring, blackout prevention and blackout recovery.
The EMS operates on mode selection, communicated from the PCS. The selected mode determines the number of generators to run and the amount of power, which is reserved for the vessel’s different main power users, especially main propulsion and the bow thruster.
Propulsion control system
The PCS is a modern propulsion control system that provides essential functionality such as propulsion control, mode selection and alarm handling. It features an 8″ panel PC at the PCS panel where all relevant data is displayed. Communication with the PCS levers is achieved through a redundant controller area network (CAN) bus, ensuring a reliable connection. A similar setup is placed in the engine room for emergency control, when the setup at the bridge fails.
On the PCS the desired sailing mode can be selected:
- harbour mode (nominal one generator online at 50 Hz),
- normal duty sailing (nominal two generators online at 50 Hz),
- heavy duty sailing (four generators online at 60 Hz), and
- manoeuvring mode (four generators online at 60 Hz).
In addition, the desired drive mode can be selected on the PCS:
- rotations per minute (RPM) mode (controls to propellors RPM setpoint),
- economic (ECO) mode (controls to drive power consumption setpoint), and
- Cruise mode (controls to vessel speed setpoint).
Finally, the PCS features a design consistent with the look and feel of the other components of the Automation Platform, ensuring seamless integration and a familiar user experience.
Vessel performance system
The VPS is based on predefined key performance indicators (KPIs) that focus on overall performance and especially on the drive train’s performance, from fuel consumption to propeller thrust and vessel speed. A technical dashboard displays measurements and third party information to personnel on shore. The KPIs facilitate both maintenance and operational personnel involved with the vessel. Trip-reporting with carbon emissions is one of the features.
In short, with the Eekels/Marpower solutions, the Vertom Labrax 7000 series is capable of highly efficient performance with a future-proof sustainable electrical platform.