SRE Controls, Inc.
Chinese Cycle Association
Shanghi, China
02/19/2005
Proprietary & Confidential.
1
Agenda………….
 Greetings & Introduction
 Engineering Challenges with Controllers.
 Goals when designing controllers.
 Advanced Technologies.
 SRE Company Overview.
 Summary & Questions.
02/19/2005
Proprietary & Confidential.
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Engineering challenges with controllers
 How are controllers different than traditional
electronics………….sophistication!
o Higher power
o High Frequency switching
o Inductances
o Safety issues
o Electrical Noise
o Heat management
o Greater Efficiencies.
o Imbedded Algorithms.
02/19/2005
Proprietary & Confidential.
3
Goals When Designing Controllers
 High Reliability
 Manageable Cost
 Functionality
 Solid Performance
 Advance Technologies
02/19/2005
Proprietary & Confidential.
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Reliability
 Typical Reasons for poor reliability
o Vibration, all electric vehicles are exposed to vibration.
o Poor construction.
o Corrosion caused by moisture, climate & humidity.
o Poor mechanical design of packaging.
o Substandard PCB manufacturing.
o Thermal control - proper heat dissipation is critical !
o Performance margins - most controllers do not have enough
overhead to ensure reasonable life.
02/19/2005
Proprietary & Confidential.
5
Reliability Cont.
 Free-wheeling Energy
o This is the energy that is generated by the motor when it is coasting.
Two approaches to managing Free-wheeling energy.
o
Option One
•
Dissipate the energy through diodes.
• This causes a great deal of heat.
• Reduces efficiency.
o
Option Two
o Synchronous Rectification:
•
•
•
•
•
02/19/2005
Control technique utilizing MOSFETs to control fly-back motor current.
Reduces controller/battery heating and energy waste.
Improves energy efficiency.
Extends the life of electronics.
SRE Patent.
Proprietary & Confidential.
6
Costs
 Cost is always a factor in design.
 Selection of high volume automotive type components?
 Cost should include reliability data
o Un-reliable products cost 4 times more than reliable products in
service and customer problems.
 Volume production with automated design.
 Simple packaging.
02/19/2005
Proprietary & Confidential.
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Functionality
 Safety functions
o Controller should shut off if throttle fails.
o Vehicle should not move if key is turned on & the throttle is
engaged.
 Power ratings
o Power rating should be enough for the most extreme conditions.
(i.e. steep hills, large weight being transported.)
o Peak and continuous ratings should be adequate.
 Thermal protection
o Controller should protect itself from damage under any
conditions, even abuse.
 Environmental protection.
 Customer mistakes or abuse of vehicle.
02/19/2005
Proprietary & Confidential.
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Performance
 Industrial rated components during design.
 Power components are adequate & high
quality.
 Voltage ranges.
 Self protection.
o Mistakes
SRE TSP-100 Bike / Scooter Controller
02/19/2005
Proprietary & Confidential.
9
Future Technology…………….
 Wireless Technology
o
BlueTooth / Wi-Fi /RF Networking for vehicle / fleet
management.
 Application-Specific Integrated Circuit (ASIC)
o
Leverage off the next generation of devices / design tools of
FPGA vendors such as Xilinx and Altera to:
o
Reduce the complexity & component costs of integrated
circuits by migrating to On-Chip designs.
 Smaller, advanced components.
 Surface mount vs thru-hole PCB’s.
 Thermal Potting
02/19/2005
Proprietary & Confidential.
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Company Overview……….
 Established in 1990.
 Design & manufacture high performance, high-voltage microprocessor based, drive and hydraulic control systems & accessories for
a wide variety of electric vehicles (EV’s).
 SRE’s products & integrated systems are used in battery powered
vehicles across multiple applications globally.
 SRE’s technology is adaptable for the growing alternative-powered
(fuel-cell) market.
 Established executive sales & Corp. presence in China.
Scrubber
Utility
Boom
Mobility
02/19/2005
Golf Forklift AGV
Proprietary & Confidential.
GSE
Scooter
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Core Competencies……….
 Power Management
o High frequency.
o Low voltage, high current.
o 10 - 1000A, 12 – 96V.
 Motors Controls
o
o
o
o
o
o
AC
BLDC
Sep-Ex
Switched Reluctance
Permanent Magnet
Series
 Hardware Design
o Controls and Power
o Rapid Proto-typing
 Software
o Embedded to Application
software.
02/19/2005
Proprietary & Confidential.
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Summary………..
1.
The Design & manufacture of Motor Controls is critical.
2.
Cost design & functionality are key to your business.
3.
North American and Chinese Manufacturing?
4.
Advanced technology for future cost reduction?
5.
Focus on -- Reliability, Reliability, Reliability !

These have been core competencies of SRE for over a decade
………..please contact us if we can assist you with your
controller and EV requirements.
02/19/2005
Proprietary & Confidential.
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Peter McDonald
Thank You.
Questions ?
www.srecontrols.com
02/19/2005
Proprietary & Confidential.
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