AV Expert Series
Technical notes from energy innovators
Power Cycling and Test Systems
Electric and Hybrid Marine Applications
This technical note describes applications of our Power Cycling and Test Systems equipment
for Electric and Hybrid Marine Systems Development and Testing.
Table of Contents
1. Electric and Hybrid Marine System Advantages
2. Test System Applications
a. Battery Pack
b. Motor/Inverter
c. AC Inverter/Battery Charger
d. DC/DC
3. Summary and Product Solutions
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AV Expert Series
Technical notes from energy innovators
Power Cycling and Test Systems
Background: Electric and Hybrid Marine Applications
Electric and Hybrid systems offer many advantages to the Marine industry as ship operators
look to improve fuel consumption, decrease maintenance intervals and reduce emissions.
Additionally, when switching to electric or hybrid systems, the ship designer has flexibility in the
placement of the drive system and other components because they do not have to be rigidly
coupled as with typical diesel electric drive systems. Silent operation can be accomplished
with the addition of an energy storage system. The energy storage system can provide for all
hotel loads as well as ship propulsion. Furthermore, the integration of renewable energy
sources such as wind and solar is easily accomplished with these newer electric systems.
This application note discusses how our Power Cycling and Test Systems can be used to
develop and test the following major components used in Electric and Hybrid Marine systems:
1.
2.
3.
4.
Battery Pack
Electric Motor/Inverter
AC Inverter/Battery Charger
DC/DC
Battery Pack
The most critical reasons for investing in rigorous battery testing for new marine applications
are:
The marine application of batteries is among the most stringent due to the large size
and human safety concerns.
Wide range of operating temperatures.
Demanding power profiles
Simulation of mechanical vibrations, wave motion and shock during ship operation,
especially in extreme conditions.
Safety during operation and in event of an impact, no matter how mild or severe.
Volume and weight constraints.
Meeting aggressive cost targets but never at the sacrifice of system safety.
Prevention of thermal runaway, which requires battery management system (BMS)
integrated testing
Development or Design Verification Testing
This testing is used at each of the three levels of battery integration to verify whether the
battery meets the product requirements or design goals. However, it’s important to understand
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AV Expert Series
Technical notes from energy innovators
Power Cycling and Test Systems
the product use cases, application and environmental requirements before developing design
verification test plans. Key attributes of the test plan at each level are:
-
-
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Cell Level: The cell must be tested to verify if meets the product specifications in terms
of capacity, power, impedance, self-discharge and max charge and discharge rates.
This testing should occur at the extremes of the environmental conditions of the battery
design.
Module Level: Battery packs typically comprise battery modules, which are the
minimum serviceable unit in the battery pack. If so, battery modules need to be tested
to verify that all the cell performance requirements scale to this level. Depending on the
design, the battery module may need to be tested with a BMS and thermal management
system.
Pack Level: Pack level testing verifies the full design meets all the application
requirements. This testing of the complete system includes the following types of
design verification and reliability tests:
o Full battery pack performance – capacity, energy, peak power, max charge and
discharge rate and self-discharge
o Mechanical structure validation – vibration and shock testing
o Thermal management validation – environment chamber testing to verify thermal
management system maintain individual cell temperatures and balance
o BMS validation – simulation typical and adverse operating conditions verify that
the BMS maintains the performance of the battery pack in terms of performance
and safety. For example, BMS validation can verify the BMS can maintain the
cell balance over time and different operating conditions.
Hardware in the Loop (HIL) Testing
Hardware-in-the-Loop (HIL) testing provides a platform on which to accurately assess the
performance of the battery system and auxiliary components before the vehicle is built.
Furthermore, it allows for seamless integration of components in a modeling and simulation
environment with actual hardware to analyze hardware component performance.
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Technical notes from energy innovators
Power Cycling and Test Systems
AV’s Power Cycling and Test Systems are the industry standard for accurate, flexible and
reliable battery development and testing. AV’s Test Systems are used worldwide for all
aspects of battery HIL testing.
Electric Motor/Inverter Testing
Electric Motor/Inverter HIL testing is critical to the development of the control algorithms and
durability/reliability verification testing of the Marine drive systems. This level of HIL testing
requires a battery simulator to provide the power source and regen load of the system. The
battery simulator should emulate the dynamic response of an actual battery system so that the
control algorithms and hardware can be tested and developed under real world conditions. For
example, how does the control system react to a regenerative pulse that hits the battery
voltage limit?
AV’s Power Cycling and Test Systems have the ability to realistically emulate a battery through
the use of the voltage mode operation and a battery model in the control software.
AC Inverter/Battery Charger
The AC Inverter is critical to the Hotel loads of the Ship. New Inverters are available that allow
for bi-directional operation such that they can not only provide power to the ships grid but also
charge the battery. This allows the battery to be topped up while in port or when there is
excess power from the main generation system. Also, if the ship has renewable generation
the inverter can determine where the power goes, supporting the Hotel loads or charging the
battery. It is critical to verify the Inverter system can operate under all conditions that may be
experienced while in operation such as:
-
Minimum to maximum voltage range of the energy storage system
Continuous power rating
Maximum power rating at the allowed duty cycle
Voltage transients
Thermal testing
Shock and vibration testing
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AV Expert Series
Technical notes from energy innovators
Power Cycling and Test Systems
Finally, it is important to verify the battery charging function is safe and follows the BMS
command appropriately. The test equipment should mimic the battery operation while
charging to allow for verification of the charge profile and should allow for extremes operation
verifying the charger reacts accordingly. For all of this type of testing, AV’s Power Cycling and
Test Systems can simulate the battery operation and load dynamics for accelerating the
testing of the Inverter system.
DC/DC Conversion
It is important to verify the DC/DC converter is capable of handling all operating modes of the
ship including; motoring, idling, regen, and low voltage operation. The DC/DC converter is
critical to the safe and reliable operation of the ship’s hybrid system. The DC/DC converter
can be configured to provide control power to all the control system computers as well as key
accessories in smaller boats such as HVAC, lighting and entertainment systems. The battery
emulator should be able to mimic all operation modes of the ships energy storage system in
order to fully test these sub-systems.
Summary
Development and Design Verification Testing of all the major components is critical to the
timely and successful deployment of Electric and Hybrid Systems in the Marine industry. AV’s
Power Cycling and Test Systems are designed to support all of the previously described
applications due to its ability to bi-directional source and sink power and operate in current,
voltage and power control modes. The AV Power Cycling and Test Systems can be controlled
by most 3rd party control systems which allows for ease of integration into any test system.
Call or email us for a more in-depth look at our products and solutions for your Electric and
Hybrid System testing needs – our systems experts are standing by to discuss your individual
development and testing needs.
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AV Expert Series
Technical notes from energy innovators
Power Cycling and Test Systems
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