OPAL-RT RT14: Running OPAL-RT's eHS solver on NI cRIO

The 7th International Conferenceon Real-Time Simulation Technologies

Montreal | 9-12 June, 2014

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Ben BlackMarket Development Manager, Real-Time Test & Power SystemsNational Instruments

[email protected]

Running OPAL-RT’s eHS on National Instruments cRIO:

Sub-microsecond power-electronic simulation

Pierre-Yves RobertFPGA Specialist, OPAL-RT TECHNOLOGIES Inc.

[email protected]



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NI myRIO | Courseware



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OPAL-RT IP + LabVIEW + CompactRIO for HIL



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OPAL-RT + CompactRIO for HIL



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Design “V” Teaching Platform

myRIO for control paired with:

• Inverter research board (real plant)

• NI / Opal-RT HIL Trainer (simulated plant)

Inverter Research Board

6 DIO Vabc PWM

Feedback

NI / Opal-RT HIL Trainer



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First demonstration: Diode-Bridge Rectifier

This circuit simulates a three-phase voltage rectifier with various loads.

Teaching objectives:• To introduce the student with the

simulation tools

• To understand the operating principles of a diode-bridge rectifier

• To highlight the effect of the load type and value on the output voltage ripple



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Second demonstration: Boost ConverterThis circuit simulates a DC-DC Boost converter with various loads.

Teaching objectives:• To understand the operating principles of a

boost converter

• To observe and understand the effect of the load type and value on the boost output voltage

• To find the S1 switching duty cycle marking the delimitation between continuous and discontinuous operation modes.



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Third demo: Boost with external controllerWe connect the Boost converter to an external controller.

Teaching objectives:• To introduce the student with

closed-loop control, including wire connections

• To design from scratch a PI controller adapted for a boost converter

• To find the suited controller parameters according to load characteristics

Boost model(cRIO)

Boost Controller(myRIO)

VL_outVL_out

S1

NI9263 ch0

NI9401 ch0

C AI0

C PWM0



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What is eHS ?

• This approach uses the modified nodal analysis.

• It solves the conductance matrix of the network to find the voltage at each node and the current from each sources.

• The conductance matrix is loaded into the solver when the model is deployed.

• The simulated model can be modified without recompiling the bitfile.

Graphical circuit design and offline simulation

Automatic analysis of the circuit netlist and generation

of the conductance matrix

FPGA-based simulation on circuit-independent

firmware



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Integration of eHS into the LabVIEW environment

• The eHS tool will be included as a module of LabVIEW.

• Exercises will be provided with pre-compiled bitfiles for the FPGA firmware.

• To accommodate different I/O configurations, custom bitfiles can be generated using LabVIEW FPGA.



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Modifying the simulated circuitTo modify the component values in a circuit, the student generally chooses from a list of pre-defined scenarios. eHS matrices are pre-generated to match these scenarios.

• In general, this is done in a LabVIEW control panel provided him by the teaching assistant.



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Modifying the simulated circuitAlternatively, the student could use a standard schematic editor, and re-compile the corresponding conductance matrix.

• At the time being, this is done within the Matlab environment.



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Creating new exercisesA professor may want to modify scenarios, create new ones, or even create exercises based on completely different circuit topologies

• The new circuit can be designed with his favorite schematic editor

• LabVIEW provides full access to the control panel for scenario control.



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eHS: Computation timeOn the cRIO, the eHS feature uses a 160-MHz clock.

• This enables very small computation step sizes, in general between 125 ~ 500 ns.

• Computation step sizes depends on the circuit complexity and the number of scenarios implemented.

• Loop rate of the Boost Converter model is 3.33 MHz (300 ns).

• Loop rate of the Diode-Bridge Rectifier model is 2.16 MHz (460 ns).

• Loop rate of the Buck Converter model is 7.27 MHz (140 ns).

• Loop rate of the 3-Phase Inverter model is 2.38 MHz (420 ns).

S1

VDC

Iload

Vload

S1

S2

S3

S4

S5

S6

VDC

VDC

Iload, A

Iload, B

Iload, C



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eHS: Hardware-in-the-Loop simulation timing

When eHS is connected to an external plant or controller, the total loop time must include I/O latency

In this case, the loop time is not critical, but the Boost model and digital lines still need to run fast to accommodate fast-switching PWM controls.

eHS on cRIO Zync

300 ns

Controller(?? us)

VL_out

S1

NI9263 Analog Output

8 us

NI9401 Digital Input

100 ns



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eHS: Supported Circuit editors

As of today, the eHS circuit can be described with one of the following tools:

• SimPowerSystem Toolbox for Simulink

• PLECS

• PSIM

Development is planned for the following tools:

• Multisim

• EMTP-RV



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RUNNING OPAL-RT’S eHS ON NATIONAL INSTRUMENTS cRIO: SUB-MICROSECOND POWER-ELECTRONIC SIMULATION

• By running Opal-RT’s eHS on a National Instruments cRIO platform, the simulation of power-electronic circuits can be performed at sub-microsecond sample times.

• The low cost of the eHS-cRIO solution makes it suitable as a model-based test bench in an undergraduate educational lab equipment.

• The flexibility of the eHS-cRIO solution enables a full hardware-in-the-loop solution with loop times in the order of tens of microseconds.

• Opal-RT can provide a variety of models suited for educational purposes, such as DC-DC converters, Inverters, Rectifiers, etc.



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Appendices



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The 7th International Conferenceon Real-Time Simulation TechnologiesMontreal | 9-12 June, 2014

eHS: PEJOVIC METHOD

• The Pejovic method models switches by either an inductor when conducting or a capacitor when blocking in the nodal matrix.

• This method is called the fix-Y because the conductance matrix does not change when a switch changes state.

• When using the modified nodal analysis the main difference between an inductance and a capacitor is in their discretization and in their historical term. Once discretized, the equivalent circuit is a current source with a shunt resistance.

OPAL-RT RT14: Running OPAL-RT's eHS solver on NI cRIO

Technology

Transcript of OPAL-RT RT14: Running OPAL-RT's eHS solver on NI cRIO