IEEE Electrification Magazine - September 2017 - 72

MPC
Status

Configuration
Load

Pload

Power-Smoothing
Controller
-

Pref

Battery

Pbattery

Power Producer
Figure 4. An MPC configuration of the bandpass filter that controls
the power smoothing done by the battery.

Design, Testing, and Verification Using
a Simulator and Laboratory
System simulators are needed to investigate the performance of the entire system. The Marine Vessel and Power
Plant System Simulator includes hydrodynamics, power
systems, and control systems. The simulator models a
marine vessel and is targeted for simulations of DP systems and how they interact with the power plant. Figure 5
shows how a DP vessel is modeled with environmental
loads (ocean current, wind, and waves), a hydrodynamic
model of the vessel, a state observer, a DP controller,
thrust allocation, and the electric power plant.

The model is also suited for simulation of fault events,
such as a sudden disconnection of a generator set. A fault
recovery method is modeled such that the load demand of
the power plant is decreased to avoid under frequency.
This is possible by reducing the power of the vessel's
thrusters. Therefore, the vessel will start to drift off. This is
an example of a case where a system simulator captures
the interaction effects between multiple subsystems of a
marine vessel. This simulator has been used to establish
decision-support systems for configuration of marine
power plants based on fault-event simulations. It is also
used to simulate realistic electric load demand for establishing battery control systems.
The hybrid marine power lab is a joint simulator by
the Centre for Autonomous Marine Operations and Systems, ABB, and SINTEF Ocean. The lab consists of two
generator sets and two induction motors with torque
brakes (Figure 6). The diesel engines (200 and 400 kW) and
generators can run at variable speeds, which allows the
opportunity to reduce the fuel consumption by running
the generator set at optimal speed (Figure 7). The generators are connected to a dc grid through thyristor-based
rectifiers. The induction motors are powered by two
inverters connected to the dc grid. In addition, a 45-kWh
battery pack and a supercapacitor bank are connected to
the dc grid through dc/dc converters.
This line up provides the ability to test new control
approaches suitable for dc grids. The diesel engine

Environmental Disturbance:
Wave, Wind, and Current Loads
Vessel Motions:
Position, Velocity, and Acceleration
Thruster Forces

Power Plant States and
Operational Data
Power Management
System

Sensor System
Measurements

Power Limitations

Dynamic Positioning
Controller

Thrust Allocation
Generalized Force Set Point
in Surge, Sway, and Yaw

Figure 5. A marine power plant simulator with a DP system.

Power Limitations

I E E E E l e c t r i f i c ati o n M agaz ine / SEPTEMBER 2017

Force Set Point to
Thrusters and Main Propulsion

Thrusters and
Main Propulsion

Table of Contents for the Digital Edition of IEEE Electrification Magazine - September 2017