the hil based model validation paradigm - tools, challenges, and application...

The HIL Based Model Validation Paradigm - Tools, Challenges, and

Application ExamplesMichael “Mischa” Steurer

Leader Power Systems Research Group at FSU-CAPSEmail: [email protected], phone: 850-644-1629

39th Annual Conference of the IEEE Industrial Electronics Society

Nov 13, 2013, Vienna, Austria

Overview

• Role of Hardware-in-the-Loop (HIL)

• FSU-CAPS 5 MW power HIL (PHIL) facility

• De-risking of PHIL experiments

• Model Verification and Validation (V&V)

• PHIL examples

2

FSU-CAPS High Bay PHIL Lab

Basics of HIL Simulation Approach

• A device under test (DUT) is interfaced to a simulated environment through HIL interfaces to a real-time simulation model

• Controller HIL (CHIL)– HIL Interfaces use control level (low

voltage) signals for I/O• Power HIL (PHIL)

– Power amplifiers and/or actuators are used for interfacing

– Full power, high fidelity stimulation• DUT to be exercised in a wide range

of potentially realistic environments• Execution of extreme conditions

within controlled lab environment• DUT to be tested with systems not

yet constructed

3

SimulatedDUT

GMRG

DUTController

ControlSignalsSimulated

VabcandIabc

SimulatedTand

Real Time Simulation

CHIL Simulation

Interface

Algorithm

G Interface

AlgorithmMRG

A

B

C

DUT

A

B

C

Amplifier Dynamometer

References

andFeedback

References

andFeedback

Real Time Simulation

PHIL Simulation

DISTRIBUTION STATEMENT A: Approved for public release. Distribution is unlimited.

J. Langston, et.al., “Role of Hardware-in-the-Loop (HIL) Simulation Testing in Transitioning New Technology to the Ship”, in Proc. of IEEE Electric Ship Technologies Symposium (ESTS), April 2013

Role of HIL Simulation throughout Technology Development

4

• Modeling and Simulation dominates the entire process

• CHIL contributes heavily from proof of concept through PHIL testing– De-risk early development of

• Hardware (fast) controller• Application (slow) controller

– De-risking PHIL experiments

• PHIL supports model building and integration phases– Experimental data for model

construction and validation– Stimulation of component through

controlled transients– Integration testing through emulation

of the target environment(s)

Modeling and Simulation

ControlHIL

LimitedHardwareTesting

PowerHIL HW

onlyLab

Testing

In situ

Proof ofConcept

IntegrationTesting

Development andModel Building

Time

RelativeEffort

FSU Center for Advanced Power Systems

• Established at Florida State University in 2000 under a grant from the Office of Naval Research

• Focusing on research and education related to application of new technologies to electric power systems

• Organized under FSU VP for Research• Affiliated with FAMU‐FSU College of

Engineering• Lead Member of ONR Electric Ship R&D

Consortium ‐ ESRDC• ~$8 million annual research funding from

ONR, DOE, Industry• DOD cleared facility at Secret level

Staffing• 50 Full‐time staff of scientists, engineers and technicians, post‐doc.’s and supporting personnel

• 7 FAMU‐FSU College of Engineering faculty• 45 StudentsFacility• 44,000 square feet, laboratories and offices, located in Innovation Park, Tallahassee;

• Over $35 million specialized power and energy capabilities funded by ONR, DOE

Research Groups• Electric Power Systems• Advanced Modeling and Simulation• Advanced Control Systems• Power Electronics Integration and Controls• Thermal management• High Temperature Superconductivity• Electrical Insulation/Dielectrics

Experimental Capabilities• Integrated 5 MW Hardware-in-the-Loop

(HIL) testbed– 5 MW variable voltage / variable frequency

converter: 4.16 kVac, 1.1 kVdc– 5 MW dynamometers

225/450, 1,800/3,600; -12,000/24,000 RPM– 5 MW MVDC converters: 6/12/24 kV– Real-time Digital Simulators (RTDS,

OPAL-RT)• <2 μs step in real-time

– Cyber-physical system simulation in RT

• Superconductivity and crogenics– AC Loss and Quench Stability Lab– Cryo-dielectrics High Voltage Lab– Cryo-cooled systems lab

• Low power and smart grid labs

FSU-CAPS PHIL Test Facility

S4 S5

SS1

4.16 kV Exp. Bus (Starboard)

=

~

=

~

~

=

~

=

M2

Substation

=

~

=

~

~

=

~

=

M1

=

~

=

~

~

=

~

=

B1

SS3 S

T1

C1 C2

T7T6

4.16 kV

B2FutureFeed

12.47 kV

4.16 kV Exp. Bus (Port)

Future

B5 B6

FutureFeed SP2 SP4

S10

B3 B4

S8

B12

B15

SP

=

~

=

~

~

=

~

=

C4

T9.1

5 MW VVF AC Bus

T10.1

=

~

=

~

~

=

~

=

B13

B14

5 MWMax

DC Bus

500-1150 VDC1.5MW @ 600VDC2.8MW @ 1150VDC

T10.2

T9.2

SCC 800 MVA @ 12.5 kV

7.5 MVA, 5%

~

=~

=~

=~

=

MVDC Experimental BusParallel: 6 kV, 0.8 kA, Series: 24 kV, 0.21 kA

3.5 / 4.16 kV

0.8 MW PCM44.16kV / 1 kV (DC)

NEW – 4 x MMC convertersDelivered : Oct 28, 2013

1.5 MVA480 V bus

PHIL…Power Hardware in the Loop

Fully Integrated with Real-Time Simulator

PHIL ChallengesAccuracy, Stability, Protection

84/2013

• Real-time simulation– Fixed time-step with minimum

achievable time-step size– Limitations on the size and

complexity of simulated systems– Protection of experiment

• Amplifiers, Actuators– Limited bandwidth– Time delays – Maximum power, torque,

speed, etc.– Availability of RT model

• Interface Algorithms– Application specific– Ensures stability of PHIL setup

• Availability of DUT model for de-risking and tuning of protection• Accuracy of models used for surrounding systems (rest-of-system - ROS)

– Common issue – establishing confidence in the models

InterfaceComponent

Rest ofSystem

PHILInterfaceControls

AmplifierControls

AmplifierDeviceUnder Test

DUTController

PHIL Interface

Real TimeSimulator

Flexible Protection of experiment

06/26/2007 9

De-risking: CHIL Simulation of 5 MW “Amplifier”

InterfaceComponent

Rest ofSystem


AmplifierControls


DUTController

PHIL Interface

Real TimeSimulator


Simulated PHIL Experiment

10

InterfaceComponent

Rest ofSystem


Real TimeSimulator


AmplifierControls


DUTController

Hardware in Lab

AmplifierControls


DUTController

Transition between modes for every change in the experimental setup

Real TimeSimulator

Model Verification and Validation

• Quantitatively Assess the predictive capability of models.

• Identify– Surroundings– Scenarios– Observable Quantities– Response Quantities

• In order to be of value, these must be carefully selected

• By standardizing for common classes of components, improve quality of results

11

A

B

C

Vsrc Lsrc

A

B

C

P

N

Active AC/DCRectif ier

Vr

Rload

DUT

Vr

Ia

Ib

Ic

Va

Vb

Vc

Idc

Vdc

Time

Voltage

Vmax

Tsettle



Synergy Between Verification and Validation and HIL Simulation

• HIL can facilitate economically carrying out validation experiments on the DUT

• HIL simulation test plans can be based around scenarios for V&V (including surrounding system models, scenarios, response quantities, etc.)

• Results can be used for improvement/calibration of DUT models and/or for assessment of prediction error with models

• HIL simulation experiments can be employed at various stages of the development process (using CHIL for testing controllers, etc.)

12

Definitions ofSurroundings,Scenarios, and

Response Quantities

SimulationModels of

Suroundings

ModelVandV

HILSimulation

ModelPredictive

Capability

Experimental

Data



HIL community needs V&V guidelines and “standards”

Megawatt Scale High-Speed Generator

134/2013

VVS

Rectifier

Gearbox DynoGenerator

+-

DAQ

~

RTDS

VoltageOpen/CloseTrigger/Synch

Voltage/Current/

Duty Cycle SpeedVoltage

Current

Speed/Torque

Measured Quantities

0 0.1 0.2 0.3 0.4 0.5 0.6-0.2

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

Time (s)

ActualReference

Moved from Model to CHIL to full-scale PHIL• Offline models used nano-second time step• Startup, shutdown procedure• Steady-state and dynamic loading (ramping)

1.6 MW in400 ms

funded by

SubstationB1

T1B2

S10

B15 4.16kV

T9.1

4.16kV AC Bus

T10.1

B13

B14

DC Bus: 0-1150VDCI max = +/- 2.5 kA

T9.2

=

~

~

=

=

~

=

=

PV Inverter

Power Grid Simulation

PV Array Simulation

6.3 MVA Variable Voltage Source (VVS)

Real Time Simulator RTDS


VVS 1 VVS 2

=

~

4160/480V1.5MVAZ=5.86%

T5466/4160V3.93MVA Z=5.6%

B11

AC Bus1: 0-4.16 kVI max = 0.433 kA

AC Bus2: 0-0.48 kVI max = 1.8 kA

SubstationB1

T1B2

S10

B15 4.16kV

T9.1

4.16kV AC Bus

T10.1

B13

B14


T9.2

=

~

~

=

=

~

=

=

PV Inverter


PV Array Simulation




VVS 1 VVS 2

=

~

4160/480V1.5MVAZ=5.86%

T5466/4160V3.93MVA Z=5.6%

B11

AC Bus1: 0-4.16 kVI max = 0.433 kA


up to 1.5 MW

SubstationB1

T1B2

S10

B15 4.16kV

T9.1

4.16kV AC Bus

T10.1

B13

B14


T9.2

=

~

~

=

=

~

=

=

PV Inverter


PV Array Simulation




VVS 1 VVS 2

=

~

4160/480V1.5MVAZ=5.86%

T5466/4160V3.93MVA Z=5.6%

B11

AC Bus1: 0-4.16 kVI max = 0.433 kA


SubstationB1

T1B2

S10

B15 4.16kV

T9.1

4.16kV AC Bus

T10.1

B13

B14


T9.2

=

~

~

=

=

~

=

=

PV Inverter


PV Array Simulation




VVS 1 VVS 2

=

~

4160/480V1.5MVAZ=5.86%

T5466/4160V3.93MVA Z=5.6%

B11

AC Bus1: 0-4.16 kVI max = 0.433 kA


up to 1.5 MW

14

Dynamic HIL Testing of Large Inverters

PHIL testing of MW-scale converters is possible today!

4/2013

Low voltage ride throughFault current contributionUnbalanced voltageAnti-islanding

funded by

Inverter with 0.8 PF lagging

154/2013

See J. Langston, et al. “Power Hardware-in-the-Loop Testing of a 500 kW Photovoltaic Array Inverter”, in Proc. of IECON, Montreal, Canada, 2012

1 2 3 4 5 6 7

0.2

0.21

0.22

Time (min)

VsimVmVr

1 2 3 4 5 6 7-0.5

0

0.5

Time (min)

PsimPactQsimQact

Active Power (MW), Reactive Power (MVAR)

Voltage (kV)

Vr

I m

=

~

4

Z

T5

B11

I m

=

~

4

Z

T5

B11

I m

=

~

4

Z

T5

B11

I m

=

~

4

Z

T5

B11

VmV required to drive reactive current through T5

Simulated grid impedance X < XT5

16

T9.1

B13

B14

PHIL testing of SiC converter4.16 kVAC-1 kVDC

4.16 kV

VVS 1

T10.1

T9.2

=

~

=

~=

~

=

~=

~

=

~=

~

=

~

0…466 V

385 V

0…4160 V438 A max (cont.)45 Hz – (approx.) 100 HzSmall signal bandwidth limit approx. 1 kHz

VVS 2

0…1150 V2.5 kA max0…approx. 100 HzSmall signal bandwidth limit approx. 1 kHz

AC side DC side

RTDS

Voltage & Current

Fdbk

Voltage Ref

(Vab (t), Vbc (t))

Voltage & Current

Fdbk

Current Ref

(duty cycle)

Device under test

• Simulates surrounding system (sources, loads)

• Provides ultra-fast protection

funded by

17

Concluding Remarks

• PHIL testing is advancing rapidly– A tool to address several challenges associated with

transitioning technology (de-risking)– Emulate a wide range of surroundings and scenarios,

simulate yet unrealized systems

• Impact of PHIL interface more pronounced at MW scale experiments– Aim for close coupling between reference and amplifier but

acknowledge the limitations in the simulated PHIL setup– Develop affordable faster switching amplifiers– Improve real time simulation of models– Proper model construction and validation is key to success

• Simulation based preparation of MW scale experiments expected to save time and money– Improve development cycle– Discover hidden issues early

• Need to develop common guidelines and “standards” to accelerate adoption of HIL paradigm

500 kW PV converter in FSU-CAPS lab

Team at work in FSU-CAPS control room

4/2013

• http://www.caps.fsu.edu/documentcontrol.html

V&V: Quantification and Assessment of Model Predictive Capability

19

o oo

o ox

X

x1

x2

Simulation

Errx

Uncertainty

Numerical

Error

Prediction

y

Pyy

y

Pyy

In order to provide confidence bounds on predictions, combine • model uncertainty• numerical error• predicted model form errorinto prediction at untested operating point



DC-side: Photovoltaic Emulation

Ensure that DC-amplifier controls allow PV-emulation in conjunction with PV inverter dynamics.

4/2013 20

0.30 0.32 0.34 0.36 0.38 0.40

0.0

0.1

0.2

0.3

0.4

0.5

Voltage (kV)

-0.05 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.40

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

-0.05 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4-0.1

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Voltage (kV)

Power (MW)Current (kA)

Maximum power point

Grid-side PHIL Interface

4/2013 21

• Choice:Voltage Current, but impacts stability

• Know your limits:Filters for bandwidth adjustment

• Protect:Open loop operation through feedback gain adjustment

PV Inverter T5 AC VVS

Id, IqVmag

Vmag‐sim

Simulated Feeder

PCC

PI Controller+

‐Σ

VVS Voltage Magnitude Reference

RTDS

Hardware

Filter

Filter Controller

Currents Voltage

Trans-former

Device underTest

Mod

el/S

imul

atio

nE

quip

men

t

Trans-former

Cyber-Physical RT Simulation

Distributed Controls (DC) computing layer

Fast data links between DC and power components:

RT simulator specific

RT simulation of electric power system

RT simulation of Controls Communications

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