Tallahassee, FL, November 5-6, 2015

CAPS @ FSU M. Steurer, J. Langston, K. Schoder,

J. Hauer, F. Bogdan

NREL Technical Monitor Mariko Shirazi

Modeling and Characterizing a Power Hardware-in-the-Loop

Amplifier

AMETEK Programmable Power, Inc. Ron Brown

3rd Annual International Workshop on Grid Simulator Testing

of Energy Systems and Wind Turbine Power Trains

Motivation

Nov. 5-6, 2015 Grid Simulator Testing Workshop 2

Real time simulation

Interfaces

Power amplifier

Device under Test

Need to know response characteristics

System identification

Experiment design Predict stability and accuracy

Model building and validation

Project objective

Power Hardware-in-the-Loop Testing Amplifier interfaces with device under test

Power Amplifier Salient Characteristics

Nov. 5-6, 2015 Grid Simulator Testing Workshop 3

Operating modes

Three independent amplifier stages One amplifier per phase To be characterized

AC (90kVA) and DC (60kW) voltage source With and w/o transformer coupling Choice of voltage levels 4-quadrant

voltage (V)

0 50 100 150 200 250 300 350 400

curre

nt (A

)

0

20

40

60

80

100

120

DC Low and High

Voltage Range

voltage (Vrms)

0 50 100 150 200 250 300 350 400

curre

nt (A

rms)

0

50

100

150

200

250

AC Low and High

Voltage Ranges

Example Test Setup

Nov. 5-6, 2015 Grid Simulator Testing Workshop 4

Voltage References

RTS Protection

Monitoring, Trend Data Logging,

Data capture

Simulation of setup with model of device

under test

DC voltage function

generator

Voltage and current Measurements

(AC or DC setup)

Ia,b,c,n Va,b,c EUT

A

C

N

PE

References

Current measurements

Voltage measurement(s)

Va,b,c

AC Real Time

Model(s)

Va

Vb

Vc

DC Real Time Model(s)

Vdc

B

A

B

C

Load Bank

AC voltage function

generator

Experiment Controls

Analog and digital I/O

OS

Output status

LAN Configuration Interface

DAQ

Status, trigger, communication

Project Tasks

Nov. 5-6, 2015 Grid Simulator Testing Workshop 5

Select operating conditions

Testing Modeling Simulating

Test sets • Voltage oscillations • Voltage ramps (steps) • Load steps • Regeneration mode

PHIL example

Circuit models • Switching • Average value

Transfer functions • Instantaneous • Envelop

Selected operating conditions and test sets

Validating (current project phase)

Experiments Response quantities/Metrics

PHIL Design Apply model and determine stability

Example Test Sets with Resistive Loads

Nov. 5-6, 2015 Grid Simulator Testing Workshop 6

voltage (Vrms)

0 50 100 150 200 250 300 350 400 450

curre

nt (A

rms)

0

50

100

150

200

250

Low V Range

High V Range

-HV Range

R/3.0

R/4.0

R/5.0

R/7.2

R/2.0

R/1.5

1.0*R

1.5*R

4.0*R

10%25% 50% 75% 100%

oscillations step response

AC 150 V AC 300 V

Disturbance type:

Operating mode:

R … base resistor component, 3.4 ohm, 80 A, twelve available

Modeling and Simulation

Nov. 5-6, 2015 Grid Simulator Testing Workshop 7

Core power components with information from AMETEK Sub-power stages and connections Filter Controls • Outer voltage loop • Inner current loop

Model structure Model implementation Simulating

Offline and real time parameterized models • Physics based • Transfer function

Selected operating conditions and test sets

Validating (current project phase)

Evaluate metrics that allow compare measured and simulated

PHIL Design Experiment: Apply model and determine stability

Example Response: DC Ramp

Nov. 5-6, 2015 Grid Simulator Testing Workshop 8

DC ramps

Same voltage reference for laboratory testing and simulation

time (ms)

4.5 5 5.5 6 6.5

volta

ge (V

)

0

20

40

60

80

100

120

140

ref

sim

mea

Real time simulator analog reference voltage signal (scaled)

Measured and simulated responses

Example Response: DC with Oscillations

Nov. 5-6, 2015 Grid Simulator Testing Workshop 9

Added oscillations to DC offset

time (ms)

4 5 6 7 8 9 10 11 12 13 14

volta

ge (V

)

130

140

150

160

170

180

190

ref

sim

mea

frequency (Hz)

3400 3500 3600 3700 3800 3900 4000 4100

volta

ge (V

)

0

0.5

1

1.5

2

2.5

mea

sim

reference simulation measured

Comparing measured FFT with simulated

Example Response AC

Nov. 5-6, 2015 Grid Simulator Testing Workshop 10

AC fundamental + harmonics

time (ms)

0 5 10 15 20 25

volta

ge (V

)

-400

-300

-200

-100

0

100

200

300

400

ref

sim

mea

Example Response AC

Nov. 5-6, 2015 Grid Simulator Testing Workshop 11

time (ms)

6.5 7 7.5 8 8.5 9 9.5 10

volta

ge (V

)

280

300

320

340

360

380ref

sim

mea

frequency (Hz)

0 100 200 300 400 500 600 700 800 900 1000 1100

volta

ge (V

)

0

1

2

3

4

5

6

7

8

9

10

frequency (Hz)

49.9 49.92 49.94 49.96 49.98 50 50.02 50.04 50.06 50.08 50.1

volta

ge (V

)

337.5

338

338.5

339

339.5

340

Transfer Function Identification

Nov. 5-6, 2015 Grid Simulator Testing Workshop 12

DC 200 V Mode 5.1 Ohm, Y-connected Load 0.8 pu Voltage Magnitude (Group 22)

𝑉𝑉𝑜𝑜𝑜𝑜𝑜𝑜𝑉𝑉𝑟𝑟𝑟𝑟𝑟𝑟

=𝐺𝐺

𝑠𝑠2𝜋𝜋𝑓𝑓𝑝𝑝

+ 1𝑒𝑒−𝑠𝑠𝑇𝑇𝑑𝑑𝑑𝑑𝑑𝑑 G = 0.998

fp = 1950 Hz Tdel = 50 us

Frequency (Hz)

10 0 10 1 10 2 10 3 10 4

Mag

nitu

de

0.4

0.5

0.6

0.7

0.8

0.9

ExperimentalModel

Frequency (Hz)

10 0 10 1 10 2 10 3 10 4

Ang

le (d

egre

es)

-140

-120

-100

-80

-60

-40

-20

0

ExperimentalModel

Summary

Nov. 5-6, 2015 Grid Simulator Testing Workshop 13

Real time simulation

Interfaces

Power amplifier

Device under Test

This project: Characterizes amplifier Model building and validation

Future application: Power Hardware-in-the-Loop Testing Experiment design: predict stability and accuracy

NREL Energy System Integration Facility Amplifier is base building block of grid simulator based testing