IEEE Electrification Magazine - December 2019 - 93

The specifications of some major equipment and energy carriers in the hybrid power lab are listed in Table 2. The
infrastructures of the HPS laboratory are distributed
between a lab machinery room, dedicated control room,
and battery bank compartment, along with an external
compartment for the fuel cell. The power generated by
two 30-kW modules of proton exchange membrane fuel
cells is connected to the hybrid lab, which is considered a
most suitable type of fuel cell for marine transportation
due to low operating temperature, high power density, and
modularity (or scalability). Figure 4 includes photos from
the HPS lab machinery room. Figure 4(a) displays a variable-speed engine along with the generator. Similarly, 4(b)
illustrates the eddy current brakes along with the driving
variable-speed motors for emulating the marine loads.
The hybrid power lab is fully equipped to be monitored
and operated from the control room. Several sensors in
the equipment harvest the real-time data that are then
made available for research and studies in the control and
monitoring of computers.

Research Infrastructure in the HPS Laboratory

management system, experiments such as the following can be conducted:
xx
Load sharing: This involves sharing the total load
power between two generators connected in parallel.
Load sharing may be implemented based on two control approaches, such as isochronous and droop
approach. Also, load sharing between generators and
battery can be done. This will further be discussed in
the section "Load-Sharing Scenario."
xx
Peak shaving/power smoothing: Generator sets are
connected to the load with the battery and the
supercapacitor for peak shaving/power smoothing.
The power smoothing by the battery and supercapacitor provides the instantaneous power for the
peak power during load fluctuation, and the generator will be unable to serve due to the delay from the
mechanical system dynamic. Thus, the diesel generators (DGs) generate the constant average power, and
the rest is supplied by battery and supercapacitor.
Due to the high power density characteristic of the
supercapacitor, it can provide instant high power
with a short time to the load for high power smoothing, while the battery provides the rest. It is also used

The main objective of the HPS lab is to enhance research and research-based education in the field of
marine power systems and marine electrification.
The lab is used by researchers to verify theoretical
methods and controllers. In addition, it is used in
graduate courses related to marine electric power
and propulsion. The HPS lab offers several types of
test experiments ranging from new control strategies to controlling the entire power plant. The load
emulator generates load fluctuations similar to the
real propulsion load by applying real-case scenarios
of the ship load profile. Control algorithms are
developed for the hybrid energy system to reduce
fuel and emissions through a so-called energy- and
emission-management system. By applying a control algorithm via the user interface to the central
controller or supervisory controller of the power

Vdc

Droo

PDG1, PDG2

Load (%)

Figure 5. A graph demonstrating equal droop power sharing with two
generators.

Vdc

3% D

roop

5% D

roop

-ve

-Pbatt

DG1
DG2

+ve

Battery
DG1
DG2
-ve Battery Charging
+ve Battery Discharging

Load (%)

PDG1 PDG2

Figure 6. A graph indicating unequal droop power sharing with two DGs and a battery.

IEEE Elec trific ation Magazine / D EC EM BE R 2 0 1 9

IEEE Electrification Magazine - December 2019

Table of Contents for the Digital Edition of IEEE Electrification Magazine - December 2019