Danfoss Drives has released on the market the new iC7-Marine power converters (drives), specifically developed for the sector of commercial marine and of superyachts. They are cutting-edge power modular and scalable converters, liquid-cooled and with high power density, and consequently with low overall dimensions and weights and with excellent torque performances.
Used to control and to manage the speed of on-board electric motors, to distribute energy optimally among the various present systems, to adapt the vessel’s electrical network to the port’s shore power supply in terms of voltage and frequency, the power converters have been entrusted with a key role for the energy management on board of yachts and ships equipped with hybrid or electric powertrains. Besides, considering the transition in progress towards these boat typologies and their capability of optimizing the energy use in terms of both consumption and emissions and of safety and flexibility, they are likely to become more and more crucial.
IC-7 Marine is the version developed for the marine world of the iC7 family released last year with the Automation model. They are drives designed with the goal of granting a better motor control and predictive maintenance with integrated encryption.
IC7-Marine arrived on the market after three years of tests carried out on board of Aurora Botnia ferry of Wasaline company. Scheduled ferry with hybrid-electric propulsion that transports goods and passengers along the route between Vaasa, Finland, and Umeå, Sweden.
iC7-Marine, the most compact drives in the world
On the occasion of the release of iC7-Marine, we talked with Aldo Ornaghi, Business Developer Manager for the Marine sector of Danfoss Drives, responsible for the market development in South Europe.
Important feature of this product are its sizes, «it is 40% smaller than the best solution at disposal on the market that can be compared with ours – Ornaghi underlines – It is the most compact in the world. Managing the on-board electric motors has a certain relevance inside the propulsion system in terms of space, too. Being 40% smaller than the products at disposal until now on the market means, to make an example, to shift from a five-door panel to a three-door one, it means having an engine room that is two-metre shorter. If in the industrial sector saving some space is not crucial, in the marine one it holds enormous importance. On board of ships and yachts, overall dimensions and weights should be as little as possible. I can use the space saved thanks to a more compact engine room to load more goods, in the case of a commercial ship, or to have larger spaces for guests in case of a yacht».
Liquid cooling and power density
The small sizes are the direct consequence of the high power density assured by the liquid cooling. “Currently, iC7-Marine are available only liquid-cooled. Compared to standard air-cooled products, they need no radiators and fans, the liquid allows achieving a much higher cooling efficiency: we can have smaller objects because we can cool them better. Furthermore, the liquid cooling allows reusing the waste heat, so contributing to a higher global energy efficiency”.
A new marine power converter: shaft performance
In iC7-Marine, a state-of-the-art control board, with a very high-power calculation, is used, «when we speak of power converters, we speak of industrial computers that operate to make electric motors run; due to the boards that we use, it is possible to achieve an even more precise control of the power delivered and then to obtain some performances in the electric application connected with the propulsion, we call it Shaft performance, of higher level than in the past».
iC7-Marine drives have an aluminium frame that is resistant to vibrations and to collisions, with electronics compartment with IP55 protection
Cyber security
In the cyber security ambit, iC7-Marine are designed to assure high security standards not only in the software but also in the hardware. Drives use an encrypted hardware chip implemented in all monitoring and communication elements among the drive, the network and the cloud.
The cyber security is integrated in the brand-new platform of iC7 drives, the use of an encrypted chip is a novelty in the field and being integrated in design phase, it offers a more efficacious protection and creates a secure work environment.
Three years of tests on board of Aurora Botnia
Before being released on the market, the new iC7-Marine were tested for three years on RoPax Aurora Botnia ferry that connects Vaasa, in Finland, and Umeå, in Sweden, along a course of about 80 nautical miles (148 kilometres) at “Northern Lights” latitudes.
The ferry is equipped with a hybrid-electric propulsion system that combines the motors with 2.2 MWh batteries. It is the result of the cooperation between WE Tech Solutions, which has supplied the propulsion system, and Danfoss Drives that was entrusted with the task of controlling the about 35MW of power on board of the ship with its iC7-Marine and iC7-Hybrid power converters.
The ferry exploits the low-emission hybrid technology, together with the four large storage systems in lithium-ion batteries that support the energy generation. Electric motors, the propulsion system and the functionality linked with the network are controlled by iC7-Marine inverters, which assure the highest energy efficiency and the lowest possible emissions.
How Aurora Botnia navigates
The vessel has been designed to operate with a combination of battery power, liquified natural gas (LNG) and biogas. Aurora Botnia is compliant with the target of greenhouse reduction by 2030 by the International Maritime Organization and with the next “Fit for 55” package by the European Union.
When approaching the port, Aurora Botnia shifts to the electric power supply and from here its “zero emission” life starts. After docking, the ferry connects to the onshore electricity grid via a shore power system, which allows charging batteries. Danfoss Drives power converters assure a perfect adaptation of the ferry’s electric grid to the shore power supply of the harbour, in terms of voltage and frequency. In this way, there is no need to produce electricity with the ferry’s generators.
Main specifications of Aurora Botnia
- Dual fuel with LNG as primary energy source
- Possibility to use LBG
- Electric propulsion drive with Azimuth thruster units
- Battery power for port entry/departure, peak shaving, hotel load and boost power
- Energy recovery and environmental footprint in focus
- Ice Class 1A Super
- No separators, green filter technique
- Length: 150.0 m
- Beam mld.: 26.0 m
- Draught, design: 6.10 m
- Gross tonnage, about: 24 300 t
- Deadweight, design abt.: 3 500 t
- Max. persons onboard (LSA): 1 000
- Speed: 20 kn
– iC7-Automation is air-cooled while the two new versions are liquid-cooled.
– iC7-Automation was born for industrial use, for shore applications where high performances are needed, it is the high-end product for this sector proposed by Danfoss Drives.
– iC7-Marine is designed for the maritime world, a sector where Danfoss Drives has been present for decades. Currently, it is certified RINA, ABS, BV, CCS, DNV and others are in progress.
– iC7-Hybrid is optimized for applications linked with Power to X, with transports and with industry.
(by Paola Bertelli)