Hongjie Wang, Tarak Saha , Regan Zane

Utah State University Power Electronics Lab (UPEL), ECE Department, Utah State University, Utah, USA

Subsea DC Current Power Distribution System

SELECT Annual Meeting and Technology Showcase – Logan, Utah – September 27-28, 2016

INTRODUCTION

ARCHITECTURE

SYSTEM OVERVIEW

STEADY STATE CHARACTERISTICS (EXPERIMENTAL RESULT)

HARDWARE RESULTS

Sponsored by the Raytheon Company through the Utah State University Power Electronics Lab (UPEL)

Blue (CH1): Resonant current

Light blue (CH2): Primary bridge output voltage

Green (CH4): Current in ZVS assisting inductor of leg A

Red (Math): Total current out of switching node of leg A

Steady state waveforms at full load

Blue (CH1): output current of SRC #1

Light blue (CH2): input voltage of SRC #1

Purple (CH3) : output current of SRC #2

Green (CH4): input voltage of SRC #2

Transient waveforms of two modules operating in series

Current reference step change Load step change

Hardware Setup

*PBU: power branching unit

Application Scenario

8" Depth x 16" OD

Form-fit Cage

Input current:1 A

Input voltage:

0 V to 500 V

Output current:0.33 A

Output power:

50 W to 500 W

Switching frequency:

400 kHz

Specifications

shore based dc current

sourceground connection

current to current SRC

#1

current to current SRC

#2

seawater connection

constant current

constant current

Land

Ocean

current to current SRC

#n

to load

to load

to load

trunk cable

constant current

Iout_1

Iout_2

Iout_n

Vin_1

Vin_2

Vin_n

Q1

Q2

Q3

Q4

A

B C

DIg

CinvAB(t)

LrCr

1:n

C1

C2

Cout

D1

D2

Rload+

-

vDC(t)

+

-

2

2sin( )2

out

AII

R

2

2sin( )2

out

AIV

4 2

24sin ( )2

in

A IV

R

For a given I, load R and resonant tank, the output current, output

voltage and output power increase as the phase shift angle decreases

2 2

2

1 1( ) ( )2

s r

s r

A R LC

Steady state solutions

Power Converter

Minimum

input voltage

180° phase shiftFull load resistance

Full load operating point

Long distance power distribution

• Ocean observatory systems

• Subsea oil and gas fields

No cable is needed for current return

Robustness against cable impedance

Robustness against cable faults

Multiple DC-DC converter modules in series