Download Advanced Power System (APS) Application: Electric Mobility

Advanced Power System (APS) Application: Electric Mobility and Electric Vehicle Test
Overview: This application space spans various
industries (see below) and is focused on small
battery powered (electric) vehicles. Examples
include:
•Scooters
•Forklifts
•Robots
All of these devices are battery powered and
therefore share the following power system
characteristics:
Application power system DUTs
•Battery management system (BMS): . A lot of design effort goes into the BMS to make sure it is charging and
discharging the batteries in the most efficient way and to ensure proper protection so the batteries do not explode.
Main APS test opportunity is using source / sink capability to simulate batteries and test the charge and discharge
capabilities of the BMS as well as its monitoring capabilities.
•Battery charger: Sometimes this is part of BMS. Requires power source and sink solution for testing, which is
something the APS can do. Sink capability is needed to measure charger output and the source is needed to test the
charges ability to detect when the batteries are done charging
• Batteries: Need to be tested with a current source and sink solution (simulating BMS). APS can do this.
Customer Test Challenges
How the APS helps overcome the test challenge
Continuous current source and sink
Provides continuous two quadrant operation
Protecting against power related damage
in test
Disconnect relays, smart triggering, fast OCP response, watchdog
timer
The output of the BMS is used to power the
motor, actuators, and electronics of the vehicle.
Characterizing dynamic current profiles
Current digitizer, seamless ranging, adjustable sample rate, elogging
Characterizing inrush current profiles
V and I digitizers, pre and post triggering, large measurement range
Example industries: green transportation,
automotive, industrial automation, security /
defense
Generating power transients
AWG and step function capabilities, high output bandwidth mode
•Batteries: used as power source
•Battery management system (BMS): controls
the charge / discharge of the batteries
•Battery charger: used to charge batteries.
Power range: ~100 W to 10000 W
Selling points
The major test challenge that the APS helps customers in the space overcome is providing a continuous current
source and sink versus combining a power supply with an eload which is not a continuous source and sink solution.
The following are other test needs related to the continuous current source and sink test challenge:
•Measurement calculations to determine power efficiency and battery capacity, APS can do this.
•Generating load profiles (power transients) is required to test proper battery system operation, APS can do this.
•Batteries can explode, so functional testing of BMS protection is important, APS can do this.
Caution
This application space focuses on smaller electric vehicles that are in the APS’s voltage and power range. Larger
electric vehicles, such as electric cars, are typically have too high power and voltage needs for the APS
Author: Neil Forcier Sept, 2013
Electric Mobility and Electric Vehicle Test Diagram: Mobility Power System
Load simulator
•APS acting as a dymamic load
•Eload
Charger
BMS
Provides power in
to the DUT
Battery
management
system
Payload
• Motors
• Actuators
• Electronics:
sensors, CPU,
instrumentation
Charger simulator
• APS acting as a
dynamic DC source
• AC source
Covered by other app
Battery simulator
•APS acting as a
source/sink
•PS + Eload
Author: Neil Forcier Sept, 2013
Advanced Power System (APS) Application: Electric Mobility and Electric Vehicle Test
Customer story: Robot Manufacturer
Customer DUT:
Insert picture
This customer manufacturers commercial
and military robots. They were looking to
build a flexible test system that could test
both lithium ion battery packs (28 V, 30 A,
1000 W) and the battery management
system (BMS) used in their robots. When
we showed them the APS they were very
excited because it provided a continuous
current source and sink solution which is
needed to test the battery pack as well as
the BMS.
Reasons the customer was interested in
APS:
The APS’s is continuous current source and sink
solution which is needed for testing both the
battery pack and BMS
•To accomplish this without the APS they would
have had to gone with a power supply, eload,
and switch (non-continuous) or custom circuits
(continuous but complex and hard to support)
Other reasons:
•Low current measurement capability to
measure standby currents
•Voltage and current arbs to simulate
•Dynamic motor currents
•Voltage pulse to test protection circuits
Opportunity summary:
The customer is currently waiting on an evaluation
APS power supply. Once the evaluation is
successful they will be purchasing units for multiple
test systems.
Author: Neil Forcier Sept, 2013