VECTOR R&D Task
FURTHER PEBB-1 CHARACTERIZATION EFFORTS
Presented to: PEBB Technical Review
7-9 April 1998
Robert White
VECTOR Research
Background
Previous NSWC PEBB-1 demonstrator
testing primarily focused on:
– DC-AC, 3-phase & single phase (H-bridge)
inversion
– DC to DC buck
Experimental Goals
Conduct tests and measurements designed to
Improve our understanding of the operating
characteristics of the PEBB design as a
function of standard shipboard metrics
– Extend and better define the operating range of PEBB-1
modules and demonstrators.
– Test concepts of interest that appear in the literature.
– Formulate and document direct comparisons between
simulation results and measured results
Initial PEBB-1 Checkout
• Set-up and operate a PEBB-1 demonstrator in a
manner that duplicates previous test conditions
– 60- Hz, single phase H-bridge, fixed boost, 5000 Hertz
switching frequency, low to moderate power level {120degree phase difference phase A to C}.
– Using the controller and other parts from the PEBB-0
demonstrator.
• Demonstrate effectiveness of closed loop tank
cooling system and closed loop chilled water cooling
unit in controlling PEBB operating temperatures
Phase 1 Experiments
• Sustained full 3-phase 60-Hz Operation
– Previous 3-phase tests often resulted in failure of phase B for
unknown reasons
– Determine if new configuration solves this problem
• Demonstrate Single-phase operation using only one-phase leg
– AC return through the DC midpoint
• Single-phase operation using an H-bridge and 180-degrees
between phase-legs.
– This should result in a higher AC voltage than the 120-degree Hbridge previously used.
Phase 2 Experiments
Using variable boost or LMARC:
– Full 3-phase 60-Hz Operation
– Single-phase using an H-bridge and 120degrees between phase-legs
– Single-phase using an H-bridge and 180degrees between phase-legs
– Single-phase operation using only one-phase
leg
Phase 3 Experiments
• Determine the maximum range of AC
voltage output that can be obtained through
software changes for a fixed DC input
voltage (300 volts).
• Determine the lowest practical DC voltage
needed to generate typical Navy shipboard
power, 450 volts, 3-phase Delta
– determine how power quality degrades with
reduced DC bus voltage
Phase 4 Experiments
• Determine effects of sudden load changes, both
increases and decreases.
– Propose/evaluate solutions if necessary
• Duplicate and compare measured results to
simulated results presented in Simulation of the
Auxiliary Resonant Pole Commutated (ARCP)
PEBB Inverter by PDI Division of Bird Johnson
Company, Report 506051-01 April 1997.
• Perform and compare other ARCP simulations and
measured data.
Phase 4 Experiments (continued)
• Determine the effect of varying parameters
that impact on harmonic distortion such as:
– load
– switching frequency
– boost time and technique
• Compare measured results to simulation
results where possible.
Phase 4 Experiments (continued)
• Attempt to demonstrate the following concept:
– Power Electronics 2nd edition, by Mohan Underland and
Robbins, page 226 suggests that for a three-phase inverter
with low values of mf (frequency modulation, switching
frequency/output frequency), a synchronized PWM should be
used with an mf that is an odd integer and a multiple of 3.
– This would suggest that for an output frequency of 60, a
switching frequency of either 4860-Hz or 5220-Hz would be
preferable to a switching frequency of 5000 Hz.
– Compare results to predictions and evaluate impacts on PEBB
design and costs
Long Range Plans
• Further characterize PEBB-1 module (phase
switch and AC switch) turn-on and turn-off
characteristics with the LEM or similar
equipment. Determine the delay-time and
characteristics between gate-driver input
turn-on/off signals and actual switch
operation.
Proposed PEBB-1 Experiments
• Determine maximum 3-phase 60-Hz (400
Hz, 15 Hz or other frequencies of interest)
450 volt power output possible with:
– Optimized LMARC software.
– Improved PEBB-1 module cooling using the products
from the VECTOR Thermal Studies task or inputs from
other organizations.
• Demonstrate efficient AC to DC conversion
using ARCP.
Additional Proposed PEBB-1
Experiments
• Demonstrate efficient 60-Hz to 400-Hz 3-phase
frequency changing.
• Demonstrate efficient DC-DC boost.
– Determine the maximum potential boost ratio possible.
• Demonstrate optimum ramp-starting of a typical
Navy Air Conditioner or Air Compressor.
• Demonstrate ARCP control of a switched
reluctance motor.