Background and activities

Jon Are Suul is Adjunct Associate Professor in marine electrical systems at the Department of Engineering Cybernetics, supported by Ulstein. He also works as a Research Scientist at SINTEF Energy Research. He holds a PhD from NTNUs Department of Electric Power Engineering, and his main research activities are related to modelling, control and analysis of power electronic conversion systems. 

 

Specialization Projects for 2020/2021

1

Control of power converters for flexible system integration of single battery installation in a two-bus ship power system

2

Sizing and control of energy storage in hybrid ship power systems

3

Optimal selection of mode of operation for marine vessels with hybrid power systems

4

Power converter operation in weak ship power systems

5

Virtual Synchronous Machines in hybrid ship power systems 

6

Power converter operation in weak ship power systems

7

Representation of time-delay in state-space models of power electronic systems

8

Control of Wireless Power Transfer Systems for Maritime Transport Applications

9 Integration of autonomous driving and wireless charging for a small-scale electric truck model
10 Optimization and control of modular converter topologies with integrated batteries

 

1 Control of power converters for flexible system integration of single battery installation in a two-bus ship power system

Introduction of batteries as energy storage in diesel-electric ship power systems can allow for significant fuel savings and contribute to the reduction of emissions in several different types of vessels. While many new vessels are currently being constructed with onboard batteries, there is also a significant potential for environmental and economical benefits from retrofit installations of battery storage systems. However, many existing vessels will have additional constrains in terms of space and system configurations compared to vessels initially designed for hybrid power systems with onboard battery storage. Thus, to the need for reconfiguration of the onboard power system and the corresponding cost of a retrofit installation in a typical two-bus ac ship power system, it can be relevant utilize a single battery unit interfaced to both the main busbars. For such solutions it can be possible to utilize the converters interfacing the battery to the ac busbars for enabling power transfer between the two parts of the system even if it is operated with open bus-tie breaker. Furthermore, such a system configuration can be expanded to allow for utilizing all the installed converter capacity of the battery system to support the healthy part of the system in case of power system faults. This project should study the control of the power converter interfaces of a single battery installation in a two-bus ship power system and evaluate how these converters can be utilized for supporting the system operation under normal and faulted conditions.

 

This project will be conducted in collaboration with Blue Ctrl AS and Ulstein Design & Solutions AS.

Supervisors at ITK: Jon Are Suul

Co-Supervisors: Espen Skjong, espen.skjong@bluectrl.io, Egil Rødskar, egil.rodskar@ulstein.com

 

2 Sizing and control of energy storage in hybrid ship power systems

Introduction of batteries as energy storage in diesel-electric ship power systems can allow for significant fuel savings and contribute to the reduction of emissions in several different types of vessels. When designing a hybrid power system, the energy storage capacity should be optimized with respect to the operational requirements, the expected load profiles and the lifetime of the batteries. However, for online operation of a hybrid ship power system, the Energy Management System (EMS) should be designed to continuously optimize the utilization of the available battery storage according to the actual loads and the changes in operating conditions. In this project, methods for sizing of a battery storage system for a hybrid ship power system and/or the design of the required EMS functionality should be studied.

This project will be conducted in close collaboration with Blue Ctrl AS and Ulstein Design & Solutions AS, and the sizing and/or the EMS design can be based on data from actual ship operations. As part of the specialization project or a subsequent Master thesis, it can also be possible to organize a guest stay onboard a vessel during a mission of 1-2 weeks, to obtain real-life experience from operation of a type of vessels that can benefit from (retro-fi) installation of battery storage. The project can be suitable for one or two students.

A similar project description is also announced at the Department of Marine Technology, and students from the different departments can work together within the overall scope of the project.

 

Supervisors at ITK: Jon Are Suul, Marta Molinas

Supervisor at IMT: Mehdi K. Zadeh

Co-Supervisors: Espen Skjong, espen.skjong@bluectrl.io, Egil Rødskar, egil.rodskar@ulstein.com

 

3 Optimal selection of mode of operation for marine vessels with hybrid power systems

While battery energy storage systems can provide environmental and economic benefits when introduced in the power system of marine vessels, they can also add flexibility and enable new modes of operation. Such systems are typically operated with a Power Management System (PMS) that ensures the balance between generation and load with sufficient available reserves, and an Energy Management System (EMS) that controls the charging state of the onboard battery storage. However, for a hybrid system with multiple energy sources it is not always obvious what will be the most advantageous system configuration and operation strategy under various conditions. This project should evaluate what would be the optimal mode of operation during different parts of a mission for a marine vessel with a hybrid power system. The evaluation could be based on minimization of fuel consumption but also other constraints like requirements of class society regulations, need for stability margins, and preferences for load distribution between available energy sources should be considered. Relevant results from the evaluation could be specified in terms of algorithms or general strategies that could serve as decision support for operation of a specific vessel.

This project will be conducted in collaboration with Blue Ctrl AS and Ulstein Design & Solutions AS. During the specialization project or a subsequent Master thesis, it can also be possible to organize a short-term guest stay with Blue Ctrl in Ålesund to familiarize with requirements for industrial PMS and EMS functionality.

A similar project description is also announced at the Department of Marine Technology, and students from the different departments can work together within the overall scope of the project.

Supervisors at ITK: Jon Are Suul, Marta Molinas

Supervisor at IMT: Mehdi K. Zadeh

Co-Supervisors: Espen Skjong, espen.skjong@bluectrl.io, Arnstein Magnussen arnstein.magnussen@bluectrl.io, Egil Rødskar, egil.rodskar@ulstein.com

 

4 Power converter operation in weak ship power systems

Diesel-electric ship power systems must be able to handle a wide range of operating conditions. While such systems are typically operated with at least one large diesel generator connected to the main ac busbar, there can be a significant potential for fuel saving by avoiding operation of a main generator under very low load conditions. This potential can for instance be utilized by introduction of battery storage systems, as widely applied in marine vessels during the last few years. However, for systems without battery storage, or in case the onboard battery system is unavailable, also other options for avoiding operation of a large diesel generator can be relevant. This project should study the potential for using a single small diesel generator with variable speed operation as the only energy source during operating conditions with very low load demand. Thus, in such operating conditions the diesel generator must be interfaced to the ac busbar by a full-scale power converter. This implies that the onboard power system will appear as very weak from the perspective of the power converter interface, since the generation and load are much lower than the normal load levels in the system. The project will evaluate suitable control strategies for this converter and study the stability of the ship power system under such operating conditions.

 

This project will be conducted in collaboration with Blue Ctrl AS and Ulstein Design & Solutions AS.

Supervisor at ITK: Jon Are Suul

Co-Supervisors: Espen Skjong, espen.skjong@bluectrl.io, Egil Rødskar, egil.rodskar@ulstein.com

 

5 Control of Virtual Synchronous Machines in hybrid ship power systems  

Energy storage systems are increasingly utilized in ship power systems to obtain fuel savings and can also allow for zero emission operation of hybrid ships in harbors and environmentally sensitive areas. If battery energy storage is utilized in a ship power system with ac distribution, three-phase voltage source converters are commonly utilized as the power conversion interface. Such converters are traditionally controlled by utilizing a Phase Locked Loop for synchronizing to the voltage at the ac bus, which is usually determined by the synchronous generators in operation. However, zero emission operation with all diesel generators turned off will require that the power electronic converters of the battery systems can control the voltage and frequency of the ac bus. The concept of controlling power electronic converters as Virtual Synchronous Machines can allow for islanded operation of a single battery storage system powering the ac bus, as well as for parallel operation of multiple VSM units or operation together with synchronous machines. This project should study the general capabilities of a VSM-controlled power converter and especially investigate methods for evaluating how a battery system with VSM-based control can influence the stability and transient response of ship power system in various operating conditions.

 

Supervisor: Jon Are Suul,

Co-Supervisors: Espen Skjong, espen.skjong@bluectrl.io

 

6 Utilization of battery systems for load disturbance rejection in ship power systems

Introduction of onboard energy storage capability is providing new possibilities for flexibility in ship power system operation. In hybrid power systems, the most common functionalities of batteries as energy storage are to provide a replacement of spinning reserve and to reduce fuel consumption by enabling more efficient operation of the diesel generators. However, batteries can also be utilized to influence the load sharing in hybrid power systems, and to compensate for oscillating loads due large onboard loads such as heave compensated cranes or other equipment. For hybrid system configurations with shaft generators and Power Take-Off /Power Take-in (PTO/PTI) capability, energy storage capability could also be utilized to relieve the diesel generator from oscillations in the propulsion load that can negatively influence fuel efficiency and lifetime. This project should study the application of disturbance rejection control as part of the operation of a PTO/PTI configuration combined with a battery storage. It can also be studied how the control for load disturbance rejection by the battery storage system will influence the stability and transient response of the overall ship power system.

 

This project will be in collaboration with Ulstein Design & Solutions AS and Blue Ctrl AS

 

Supervisor: Jon Are Suul,

Co-Supervisors: Egil Rødskar, egil.rodskar@ulstein.com, Espen Skjong, espen.skjong@bluectrl.io

 

7 Representation of time-delay in state-space models of power electronic systems 

Power electronic converters are increasingly utilized as the grid interface of generation systems and loads in ac power systems. The tuning of conventional cascaded control systems for such power electronic converters can have significant impact on the stability and dynamic response of the converter as well as local power systems. Linearized state-space models are commonly utilized for assessing the small-signal stability and controller tuning of traditional power systems as well as for modern power systems with increasing share of power electronic converters. However, the time-delays in the control system implementation for power electronic converters have significant influence on the stability but cannot be easily represented in continuous time state-space models. Accurate stability analysis of power electronic converters with low sampling frequency can be based on discrete time models, but such models of individual power electronic converters in the z-domain cannot be easily integrated with continuous time state-space models (or s-domain models) of larger systems. Furthermore, many of the tools for eigenvalue-based analysis of small-signal dynamics, parametric sensitivity and interaction analysis by participation factors are not easily applicable in the z-domain. This project should evaluate how bilinear transformations can be utilized for accurate representation of time delays in traditional state-space models of power electronic converters that will be suitable for integration in larger system models for eigenvalue-based analysis of small-signal dynamics.

 

Supervisor: Jon Are Suul

 

8 Control of Wireless Power Transfer Systems for Maritime Transport Applications 

Inductive, wireless power transfer has been demonstrated as a safe, efficient and reliable way of transferring power for battery charging in maritime applications without any physical contact between the sending and receiving units. However, the challenges of design and control of such systems are closely related and must be carefully considered in a coordinated way. One major challenge in wireless charging for maritime applications is to ensure precise control of the power flow, while keeping the transfer efficiency as high as possible, during variations in the magnetic coupling between the sending and receiving units.

The task of the student will be to study the modelling and control of wireless inductive charging systems under various system configurations and operating conditions. This evaluation should form the basis for design of a suitable control system that will avoid the need for high-sped communication between sending and receiving side of the system. Potential application of reduced-order observers resulting from the first part of the investigation should be considered as part of the control system design.

The specialization project will be developed in collaboration with SINTEF Energi and can be suitable for up to 2 students.

 

Supervisor: Jon Are Suul, Jon.are.suul@ntnu.no

Co-supervisors: Dr Giuseppe Guidi, giuseppe.guidi@sintef.no

 

9 Integration of autonomous driving and wireless charging for a small-scale electric truck model 

Technology for dynamic inductive power transfer can allow for battery charging of moving vehicles. Several concepts for utilizing such technology to enable long distance electric road transportation is currently under development. Technology for dynamic wireless power transfer to electric vehicles is also envisioned to be suitable for autonomous vehicles, since it allows for fully automated long-term operation and continuous energy supply without any needs for manual intervention or interruption of regular operation.

At SINTEF Energy Research, a small-scale model of a system for dynamic inductive power transfer to a moving vehicle has been constructed as part of the IPN-project ELinGO (https://www.sintef.no/projectweb/elingo/). The system consists of a set of road-side coils that can supply energy to a radio-controlled electric truck model in scale 1:14, and the wireless charging could in theory ensure continuous operation of the system. A student project in 2019 has implemented autonomous driving functionality on the model, including a path-following strategy. The task in this project will be further integrated the control of the wireless charging with the autonomous driving for automatic positioning of the vehicle when passing the road-side coils.

The project will be in cooperation with an internal research project on technology for electrification of transport at SINTEF Energy.

 

Supervisor: Jon Are Suul,

Co-Supervisors: Dr. Giuseppe Guidi, Giuseppe.Guidi@sintef.no

 

10 Optimization and control of modular converter topologies with integrated batteries  

Large-scale battery systems are becoming a viable option for energy storage in a wide range of applications for electric transportation and for energy balancing in power systems. Traditionally, large-scale battery systems are operated with multiple parallel strings constructed by low voltage battery modules that are series-connected to reach voltage levels in the range between 400 V and 1000 V. Each string or a group of strings are then connected to the power system and controlled by a dedicated power electronic converter. However, the series connection implies that the operation is limited by the weakest module or cell in each string. An approach to avoid the limitation on voltage and reliability introduced by series-connection can be to utilize modular converter topologies that allow for integration of a battery module at floating potential in each module of the converter. Such topologies have already been applied for large-scale energy storage in wind farms, but also have a potential utilization in transport applications, including hybrid ship power systems. This project will address the challenges of optimizing the operation and control of such systems. The work of a student can be focused on estimating the conditions of the battery modules for balancing the load on each module and/or on the control of the converter topology.

 

Supervisor: Jon Are Suul,

Co-Supervisors: Dr. Giuseppe Guidi, Giuseppe.Guidi@sintef.no, Prof. Marta Molinas

 

 

Teaching

TTK24 Control of Marine Power Conversion Systems

 

Scientific, academic and artistic work

A selection of recent journal publications, artistic productions, books, including book and report excerpts. See all publications in the database

Journal publications