Inductive Charging System Technical Approach for University of Washington APL’s ALOHA Project

1. Inductive Charging System Technical Approach for University of Washington APL’s ALOHA Project 1/7/2004 Karl Conroy President S&K Engineering, Inc Confidential

2. System Components Float Side Microcontroller PC/104 based hardware to minimize Development Local Battery Management through Shunt Regulator On/Off Control of SRC Data Link Communication path Communication to other systems Series Resonant Converter High Frequency AC Current Source Drive Inductive Coupler Constant Frequency (Open Loop) Operation Shunt Regulator Active Resistance to Provide constant power RF/IR Transceiver Short Range Link Explore Off the Shelf Options RF in 100s of MHz or IR in 800nm Same Device on Both Sides System Components Vehicle Side Microcontroller Battery Management on Crawler Side Charge Algorithm Implementation Voltage and Current Sense State of Charge Tracking Communication to other systems on Crawler Data Link Communication path Low Power Consumption uP Active Rectifier Pass or Shunt HFAC Current High Electrical Efficiency Convert HFAC to DC Power Interface to Battery HF Filtering RF Transceiver Same Device on Primary Side Charging Algorithm Stop charge if Tbat < 0°C or Tbat > 45°C Charge at constant current until Vbat > 4.1V Then charge at constant voltage until Ibat < 10% of initial current Terminate charging on low current to maximize charge Stop charge if Vbat > 4.3V Stop discharge when Vbat < 2.3V Inductively Coupled Charging System Electronics S&K Engineering, Inc. Confidential

3. System Components Float Side Core “C” core design Angled interface to secondary core reduces gap Flexure Provides necessary degrees of freedom for core alignment Enidine Wire Rope isolators (possible off the shelf device) Absorb impact of vehicle Guide Structural support of Primary core Attachment to floater Houses communications interface Primary Winding Litz wire (Size, Turns: TBD) Floater Electronics Enclosure Vehicle-Float Battery Charger Shunt Load Float Battery Bank 6-8” ID cylindrical pressure housing HFAC Cable Litz wire Interface from Charger to Coupler Communications wire System Components Vehicle Side Core 3/4 “C” core design Angled interface to secondary core reduces gap Guide Provides initial alignment of cores Reduces drag by secondary core Houses communications interface Structure to Crawler Provide attachment of secondary to crawler Secondary Winding Litz wire (Size, Turns: TBD) Vehicle Electronics Enclosure Provided by vehicle Vehicle charger integrated into enclosure HFAC Cable Litz wire Interface from coupler to Crawler Electronics Communications wire Inductively Coupled Charging System Mechanical S&K Engineering, Inc. Confidential

4. VEHICLE BATTERY External Communication PRIMARY SIDE POWER SYSTEM MICROCONTROLLER Input Power From Mooring Cable SHUNT REGULATOR PRIMARY SIDE BATTERY CHARGER DC-HFAC CONVERTER Series-Resonant 100kHz FLOAT BATTERY RF/IR TRANSCEIVER DATA Link High Frequency AC Power FLOAT CRAWLER Short Range RF/IR Link Inductive Power Coupler High Frequency AC Power HFAC-DC ACTIVE RECTIFIER REGULAOR RF/IR TRANSCEIVER DATA Link CRAWLER SIDE POWER SYSTEM MICROCONTROLLER CHARGE CONTROLLER On-Board Communication S&K Engineering, Inc. Confidential

5. Inductively Coupled Charging System Mechanical Guide (attached to Floater) Flexure (3-6) Charger Cable Primary Core Secondary Guide Secondary Core S&K Engineering, Inc. Confidential

6. Inductively Coupled Charging System Mechanical Guide (attached to Floater) Flexure (3-6) Crawler Cable Secondary Guide Secondary Core Primary Core S&K Engineering, Inc. Confidential

7. Inductively Coupled Charging System Mechanical Guide (attached to Floater) Location of Communication Link: Primary Secondary Secondary Core Guide Primary Core S&K Engineering, Inc. Confidential

8. Inductively Coupled Charging System Mechanical Secondary Core Guide Guide (attached to Floater) Secondary Core Angled core interface Crawler cable Primary Core S&K Engineering, Inc. Confidential

9. Charging System Requirements • Operating Depth: 5000m (16,400 ft) • AO J-Box Supply Power < 100W • Mooring Cable Voltage 250-400VDC • Float Supply Power arbitrary • Charge Time < 6 hrs (minimize) • Interval between chargers ~ 4 days • Data Transmission Bi-directional • Data Rate >100kbps • Vehicle Comm RS422 protocol • Battery Voltage 12 VDC 10.8VDC nominal • Battery Chemistry TBD (Lithium-Ion?) • Peak Charging Current < 20 amps • Supply Voltage 48 VDC • Charging Power 250W • Charger Efficiency > 90% • Charge Algorithm Remotely Programmable (constant current then constant voltage) • On Board Size 6-8” ID cylindrical pressure housing • On Board Weight TBD (minimize) S&K Engineering, Inc. Confidential

10. Charging System Requirements • Connectors TBD • Operating time >5 years • Other Removable from cable Constant power draw from AO JBox Resistant to marine bio-fouling • Off Board Size 6-8” ID cylindrical pressure housing • Off Board Weight TBD (minimize) • Reliability Hi-rel components where appropriate consider redundant components/circuits minimize stress on components – thermal, electrical, etc. S&K Engineering, Inc. Confidential