System

Software

Human Machine Interface

Motors

400kW motor installed on demonstrator

Batteries

Electronics

Safety

Range extenders

ICE range extender

Charging

System for management of entire energy platform is absolutely key factor for a successful. System contains not only software and hardware, it needs to be treated all together. In our team we have 6 people that works on system – 3 on system side, and 3 on pure software development. We have modular approach so possibilities to adapt for future applications is much bigger, compared to other companies. We use only hardware that we either know form previous projects, or something that is tested by us. We all have extensive knowledge and experience of project of different scales of complexity. Our engineers have been involved in projects that sussed and failed – we know what should be avoided and what are the bets practice to minimise risk of failure.

Our software is embedded – which means it is integrated with hardware. Wherever it is needed we have redundancy on both ends – electronics & software, to be sure that our solution is safe and easy to operate. System on our demonstrator is made with 40 different components, all connected together with 6 computers and 11 CANbus lines, and 3 ethernet networks. We have more than 3000 parameters that are not possible to be handled manually.

We use Model Based Design approach, so it is relatively easy for us to understand on what is happening in the system, and what is possible, and how difficult to implement. The same approach is industry standard for automotive and aerospace applications.

With our system we are able to handle errors of each component, predict failures and adapt system to it.  Most advanced prat of the system is handling of batteries. In our case we are able to use large energy storage systems, and make system work even if single cell, battery bank or string has a failure and is out of operation.

Our software is embedded – which means it is integrated with hardware. Wherever it is needed we have redundancy on both ends – electronics & software, to be sure that our solution is safe and easy to operate. System on our demonstrator is made with 40 different components, all connected together with 6 computers and 11 CANbus lines, and 3 ethernet networks. We have more than 3000 parameters that are not possible to be handled manually.

We use Model Based Design approach, so it is relatively easy for us to understand on what is happening in the system, and what is possible, and how difficult to implement. The same approach is industry standard for automotive and aerospace applications.

With our system we are able to handle errors of each component, predict failures and adapt system to it.  Most advanced prat of the system is handling of batteries. In our case we are able to use large energy storage systems, and make system work even if single cell, battery bank or string has a failure and is out of operation. It is worth noting that HMI is operated by a separate computer, which is redundant as well.

Our main supplier of electric motors is Danfoss Editron. Permanent magnet technology is standard these days. We use motors that has its extended variation named Synchronous Reluctance assisted Permanent Magnet (SRPM) technology. It means that this motors has not only very high efficiency (~96%) but as well achievable over large operation range.

In the same time it is combined with direct shaft propulsion – so mechanical losses are very small. We have been doing a lot of studies on use of other propulsion technologies (sterndrives, water jets etc.) and we have found that, in case of our demonstrator, most effective is direct shaft drive.

Our system is ready to work with other suppliers, and for smaller powers (75-110kW) we are testing ultra-lightweight solutions with gear boxes, where efficiency is not the main driver, but compact size & lowest possible weight.

We are always providing power details as continuous operation, due to nature of  marine usage. In permanent magnet motors most critical parameter is temperature of magnets, so real efficiency, and maximum power highly depends on coolant temperature. Typical motors (adopted from automotive), have very high  output power, that is not mentioned as peak (for 10-15s). Continuous output power is normally just have of it, and this is something that corresponds to how typical boats are used.  

In fact marine application requires something more than just batteries, they require Energy Storage System. This is something much complicated and sophisticated compared to just battery. The simplest ESS is made with only one battery pack and electric box with some electric and electronic components used for safe operation, and disconnection when something is in out of operation range, or when battery is not ready for use. This system is sophisticate by itself, and is part for what is delivered by a battery supplier.

In case of our systems we use large systems, with several strings. Each string is made with several battery packs, connected parallel or serial, depends on needs and possibilities. There are very sophisticated algorithms to make it work, when multiple strings. Use of multiple strings is a safe way for making system larger, but requires experience and test to make it work.

High Energy

This is most popular type of batteries, in most cases it is NMC or LiFePO chemistry. This type of batteries have high energy density. It means that they can store a  lot of kWh in smaller volume, and with lower weight. Disadvantage is relatively low output power (compared to capacity) and lower values of charging power. Number of cycles depends on operation modes  -and is in range of 3000 to 5000.   

High Power

For applications where battery is not main source of power (for example where range extender is used) or where typical life cycle requires many cycles (like ferries operating every 30 minutes) different technology is used. In such cases LTO is the most common choice. This technology has smaller energy density, but for given capacity can deliver much more power. In the same time it can be charged with very high currents. This technology can withstand, without degradation more than 20%, up to 50 000 cycles.

In general, battery system is a heart of each system, and is the most sophisticated part of it. In most cases it is real limiter of performance. Not everyone is aware of fact that power that can be delivered by the system depends on temperature, state of charge, state of health and more – of the weakest cell in the system.

We use marine certified electronics (not all industrial solution has it), that is designed to work in harsh environment. Our solution consists redundancy on hardware level – basically all system critical components are doubled. All components that we use have long term support form producer. We are testing our solution in real life, and we are making adjustments wherever it is needed. One of the most important factors is Electromagnetic compatibility (EMC). In principle all components for hardware are EMC certified, but when system is connected and working it needs to be checked and verified. EMC is one of the biggest challenges and tasks in every e-mobility project.

Our system includes IMD (insulation measure devices) and high and low voltage systems. We have as well, additional and independent safety system based on SICK solutions.

Range extenders are types of devices that generates power and extends vehicle range bigger, than on energy for batteries only. On of the bets known examples is BMW i3. Range extender is producing only electricity, that later is used by electric motors for propulsion. In our case we have two type of range extenders – based on internal combustion engine or on hydrogen fuel cell.

In Sialia 57 project we had a need for high power range extender, that is lightweight. Our solution is based on FPT engine and permanent magnet Danfoss generator. All together we crated solution that works in range of 1000-3000RPM is efficient in power generation between 100 to 390kW of continuous power @700 VDC. We were testing our system for more than 6 months in our laboratory to get all knowledge and optimize its work. Our range extender starts form high voltage, and 24VDC starter is for emergency only. We are always using it in its optimal range of power & RPMs. We optimized smooth response and operation. As results we have very compact and lightweight solution that fits on 57’ yacht. Diesel can be tanked everywhere worldwide, so boat is not limited by existing charging infrastructure.

 

Hydrogen based power generation is one of possible futures of boating. Energy density of this type of solution is higher compared to lithium ion based batteries. Required volume is considerably smaller as well.

We do not have yet reference for this solution, although our team members were involved in four different e-mbile projects with hydrogen fuel cells. From system point of view we are ready.

Work with high voltage applications requires attention to details on all levels – starting from very bottom, like connection, through use of proper cables and on electronics finishing. We use top class cables, connectors and attachments. We have high attention to details on all wires, and on their routing. One of key factor sis equipotential bonding – something tat most of the people in industry is not aware of. We have systems for detection of issues with isolations, there are sensors for measurement not only electrical conditions, but as well temperatures and humidity. ICPT battery system, that is used on our demonstrator, has ~600 temperature sensors.

In e-mobility charging is one of fundamental challenges. There are two main limitations – battery, and shore power. In our case our systems are with relatively large capacities, so by default they can be charged with high powers (in automotive meanings).  Our demonstrator has 250kWh of batteries, and can be charged with power 390kW from our range extender. Typical shore powers are 11 up to 22kW @ 230-400VAC, and this are sizes for typical on-board chargers.

Single CSS socket (typical automotive for fast charging) can handle up to 350kW of DC power. Our system on boat is ready to have multiple sockets and in theory unlimited charging power. In case of large power boats with 1MWh of battery bank we can have system with 3 sockets and max charging power of 1MW.

Installation quality

HMI in Sialia 57 -0 under development
Installed 400kW electric motor on Sialia 57
Testing fecility of energy storage system for electric mtor yahct - 256kWh of capaicty,a nd max power of 800kW
Electronics box on electric motor yacht
Installation of batteries on electric power yacht
400kW @ 700VDC range extdner - variable RPM
Connetcion of high voltage batteries - electric, signal and cooling

AMPROS - Silent Straits Ltd. electric propulsion division, Continental office: Ul. Wróbla 6, 02-736 Warsaw, Poland

Advanced Electric Propulsion & Yachts