Power Electronics Development Center

Showing results for 
Search instead for 
Did you mean: 

GPIC Power Converter Control Development System (Mini-Scale SKiiP3 Replica Back-to-Back Converter)

In Stock & Available: GPIC Mini-Scale SKiiP3 Replica Power Converter Control Development Systems

These systems are a tremendous productivity booster for power conversion equipment design teams. They enable you to develop, prototype and test your power converter control code using a mini-scale replica of dual SKiiP3 power converters. The signal pinout is the same as the full-scale SKiiP3 interface board, so control code developed and tested using this mini-scale system can immediately be used with a full scale power converter. (The only thing that typically changes are your sensor scaling/gains and fault trip limits.) For potentially destructive fault testing of your FPGA-based control systems, the $11 3-phase DIP intelligent power module chips used on this mini-scale system can be replaced

Ordering Info:

For shipments to European countries, please contact Marco Schmid at Schmid Elekronik.

For shipment to North America locations only, ViewPoint Systems has the Mini-Scale SKiiP3 Replica Power Converter Control Development Systems available for $895 USD and holds stock for fast delivery. Please contact ViewPoint Systems at 585-475-9555 and reference part number VSI-S-000023 and reference quote number 6752-C. A PDF quotation is also attached below.

For ordering outside North America and Europe, please contact Chris Dickey at SVTRONICS  (chris@svtronics.com, Tel: 214.440.1234 x102) and reference quote number 10112013A.



In addition to the fully assembled 3-phase back-to-back inverter research board itself, the kit includes six 1.5 inch standoffs, a U.S. power strip, universal ATX and 15 VDC power supplies with U.S. plugs (adapter required for use in other countries), a U.S. 24VAC 50VA wall transformer with PTC fuse (this voltage transformer is for use with US 110 VAC, 60 Hz power only-- for Europe/Asia use 77DA-40-24 or similar), an Ethernet cable, a 400 point solderless breadboard, three 5.6 mH 6.1 Ohm inductors, three 47 uF capacitors, three 400 Ohm 3 W resistors, and 25 feet of 20AWG hook up wire.


Concept Definition

• 3-Phase inverter research board with direct connectivity to the NI Single-Board RIO General Purpose Inverter Controller

• Enables analog simulation of transmission and distribution systems, including Flexible AC Transmission Systems (FACTS)

• Contains two three-phase IGBT inverters, two single phase rectifier bridges, and two DC links that can be connected or used independently

• Mates with NI 9683 sbRIO GPIC to create a compact desktop development, research, experimentation and demonstration system

• Compact design on a single PCB for desktop use or mounted on the wall to a peg board

• Flexible connectivity and SMPS topology for many diverse applications (DC-AC, AC-DC, AC-DC-AC, etc.):

• Two three phase IGBT input/outputs (total of 6 two-level IGBT half-bridges)

• Two single phase AC inputs with full-bridge rectifiers

• Two sets of DC link capacitors with pre-charge contactors

• Contactor for connecting the DC-links together

• Terminals for connection of DC power supply or solar panels to the DC link

• Terminals that provide access to the voltage at the mid-point of the DC link capacitors

• On board current and voltage sensors for each half-bridge

• Removable pluggable connectors wire-poke terminals for easy wiring
          • Create multiple pre-wired connector harnesses for testing purpose, i.e. have a harness pre-wired to simulate a phase-to-nuetral fault and validate control system response

• Requires ATX power supply and 15 V floating power supply

• Utilizes 6-pack intelligent power modules (IPMs) with built in gate-drivers and thermistor temperature sensing

GPIC research board - schematic.png

Inverter Research Board Connections.jpg

In the configuration below, a MotorSolver 3-phase induction motor is connected to inverter A and a brushed DC motor is connected to inverter B in a dynomometer configuration.

GPIC inverter research board with MotorSolver induction motor dyno.jpg

Here is the GPIC inverter research board with a 24 VAC voltage transformer connected to inverter A, then rectified to DC. A PLL running in the FPGA enables the inverter to produce 3-phase sine-waves that are synchronized with the grid.

Inverter Research Board - 3-Phase RLC Load.jpg

Circuit Topology

The back-to-back 3-phase inverter circuit schematic is shown below. Two 3-phase inverters have a shared power ground connection. There are two independent full bridge rectifiers, enabling single-phase AC voltage to supply the DC link voltage. Alternately, a DC power supply can be

used to power the DC link for either inverter. There are also two independent pre-charge contactor circuits. An additional contactor is used to enable the two DC links to be connected together. Each of the IGBT intelligent power modules (IPMs) is rated for a maximum of 10 Amps of current per phase and includes thermistor temperature sensors which are connected to the GPIC scanned analog inputs. Several of the LVTTL inputs on the GPIC are converted to 5 V TTL logic levels to support interfacing to optical quadrature encoders (A, B and Index pulse), which are decoded by the FPGA to calculate motor position and velocity.

Connections for the 3-Phase Induction Motor with Brushed DC Motor Dyno and Brake Chopper Resistor:

Research Board in Induction Motor Dyno Configuration.png


  • The contactors should be open when first energizing the DC link to limit the inrush current. This prevents overvoltage damage to the DC link capacitors and overcurrent damage to the voltage transformer.
  • Do not connect the two DC links if they are charged by different sources. LabVIEW FPGA protection interlock logic is included in the example code.
  • The current per phase should not exceed 10 Amps. Overcurrent and overvoltage protection are included in the LabVIEW FPGA example code.
  • By default the IGBT modules do not have heatsinks mounted on top, so take care that the average RMS current does not exceed acceptable levels. Overtemperature protection is included in the LabVIEW FPGA example code.

Wiring Connections

Below are the typical wiring connections for use as a mini-scale grid tied inverter.

Inverter Research Board Connections.jpg

Solderless Breadboard Connections for the 3-Phase Inverter with RLC Load:

3-Phase Inverter Breadboard Connections.png

Below are the wiring connections to build your own encoder cable compatible with the MotorSolver Motors. The LUMBERG KV81 circular connectors with solder cup connections are orderable from Newark (Newark Part Number 59M7489). Alternately, prewired cable assemblies can be ordered from HiRel Systems (in which case the wire colors will not match the information below).

Timken Encoder to CAT6 Cable Harness - Lumberg KV81.png

Below are photos of a "home made" cable assembly created using the diagram above with the Lumberg KV81 connector and a piece of green CAT5 Ethernet cable. Also shown are photos of the connections to the GPIC inverter research board. In this case, ferrules are used however they don't work especially well with the Phoenix pluggable connectors. Instead of ferrules, I'd recommend just tinning the leads for the wire connections to the GPIC inverter research board. Tinned leads will give a more secure connection.

Encoder connections to research board 3.pngEncoder connections to research board 2.pngEncoder connections to research board.png

Use Case Examples

Use Case A:

1. Line frequency conversion

2. Active power filtering and conditioning

Line frequency Conversion.png

Use Case B:

1. 60Hz input and variable speed motor control

2. Chopper for battery or ultracapacitor energy storage

Variable Speed Motor Control.png

Use Case C:

1. DC input one motor driving and line voltage generation (active front end)

2. DC input with two motors driving

Motor with active front end.png

Use Case 😧

1. Photovoltaic (PV) cells to grid inverter with MPPT

2. PV cells to chopper for battery or ultracapacitor energy storage

PV to grid.png

Background and Motivation

Below are the first photos and screenshots of the new, open source back-to-back 3-phase inverter research board for the NI Single-Board RIO General Purpose Inverter Controller (GPIC). By open-source I mean that we plan to share the Multisim and Ultiboard design files so you can modify the design if needed for your research, or use it as a starting point to develop a research board with a different converter topology such as NPC or Matrix.

The idea is to create a mini-scale system that enables GPIC developers to develop, test and validate their control software before scaling up to 50 kW or higher power levels. Building mini-scale power systems for design, sizing and control development of FACTS transmission and distribution equipment has been standard practice at companies like Westinghouse for at least 30 years.

Dr. Kalyan Sen is one of many collaborators on this project. His "big hairy audiacious goal" (BHAG) for us is to create "lego bricks for the smart grid" that enable researchers to snap together lots of these GPIC research boards and develop control software that could be deployed, with minimal changes, at the full scale on the grid. For example, you can use one of these boards to switch in inductors or capacitors to create a Static VAR Compensator for power factor correction, and then use additional boards with external RLC circuits in the path to to model transmission and distribution lines, etc. It's basically an analog simulator for the power grid. It's possible to replicate the behavior of the real transmission & distribution grid with high fidelity using mini-scale systems like this and when scaled up to power levels of 80 MVA or higher, Dr. Sen comments that the control code can be about 90 percent complete and basically just needs to be retuned.

Now with the sbRIO GPIC, the control board for the mini-scale 'rapid control prototyping' system used in development can also be the same control board for the full scale system. In other words, you can develop at a mini-scale and then deploy at full scale.

Analog simulation of transmission and distribution systems, including Flexible AC Transmission Systems (FACTS)

It's been standard practice in the industry for 30+ years to use mini-scale versions to design megawatt transmission and distribution systems (for example, static VAR compensators). With this new system, researchers will be able to develop, size and prototype motor/generator and flexible AC transmission systems (FACTS) and then use the same LabVIEW FPGA code that's been designed and validated at the mini-scale when deploying a full scale version at MW power levels.

Motors/generators as well as grid equipment (transmission and distribution power lines, loads, generators and other resources) are simulated using external boards. Each GPIC back-to-back inverter research board is able to control the flow of power, and can also be used to switch in capacitance or inductance, simulate faults, and more.

This will be an open source design done in Multisim & Ultiboard, enabling researchers to customize it as needed and develop a library of different configurations.

The intended use is as a mini-scale "lego brick" for designing motor/generator and smart grid flexible AC transmission and distribution systems. An advantage is that any control algorithms and IP developed can be scaled up and deployed commercially at megawatt scales using the NI sbRIO GPIC.

Learn more:

Video: Using Small Scale Power Network Simulators for Development of Smart Grid and FACTS Control So...

Use Cases

Smart Grid Mini-Scale Prototyping (image courtesy Ohio State):

Miniscale grid simulation (courtesy Ohio State I-SMART).jpg

Flexible AC Transmission System (FACTS) Design using Mini-Scale Prototype (images courtesy Dr. Kalyan Sen):

Smart Power Flow Control.jpg

Transmission Line Voltage Regulators.jpg

Photos and Screenshots

Open Source Circuit Design for the NI GPIC Mating Board (NI Ultiboard and NI Multisim)

These design files are now included in the NI Power Electronics Design Guide. To purchase a fully assembled GPIC inverter research board, contact  ViewPoint Systems at 585-475-9555. ViewPoint currently has the NI GPIC back-to-back 3-phase inverter research boards available for shipment. 

The NI Circuit Design Suite files for the second revision are shown below. The ATX power connector is moved to the left and all the power connections are moved to a single connector on the right (Inverter A/B phase u,v,w, DC link A/B, Capacitor mid-point A/B):

GPIC Research Board Rev 2 - Ultiboard.png

GPIC research board.jpg

GPIC inverter research board - schematic.jpg

inverter A schematic worksheet.jpg

LabVIEW FPGA Control Application Block Diagram and Front Panel

Updated control application with 40 MHz fault handling logic:

FPGA 3-phase inverter control.png

Screenshots of 3-Phase Induction Motor Control

In the screenshots below, the MotorSolver Dyno is used. The shaft of the 3-phase induction motor is connected to the shaft of the brushed DC motor/generator. The induction motor is controlled by inverter A in an open loop fashion using 3-phase sine-triangle generation. The brushed DC motor is controlled by inverter B (phases u and v) using full bridge PWM. Phase w of inverter B is connected to a 27 Ohm power resistor, which acts as a brake chopper capable of regulating the DC link voltage of inverter B. Inverter B is powered by a 24 VDC supply rated at 5 Amps. Inverter A is powered by a 24 VAC voltage transformer. The DC links are not connected.

Running Steady State with Torque Load:

Induction Motor Fault - Running Steady State with Torque Load.jpg

Induction Motor Fault Caused by a Fast Jump to in the Frequency of the Sine Wave Excitation from the Inverter, and the exponential decay of the sinusoidal circulating currents in the inductor motor rotor.

Induction Motor Fault - Jump to High Frequency.jpg

Screenshots of grid-tied FPGA-based control system running with 3-Phase RLC Load

GPIC back-to-back inverter research board - running on 11-15-2012.jpg

Power Quality Monitoring using LabVIEW Electric Power Measurement Suite Tools

Unfiltered current:

GPIC back-to-back inverter research board - running on 11-15-2012 - power measurements.jpg

Filtered current

GPIC back-to-back inverter research board - running on 11-15-2012 - power measurements - current filtering.jpg

Phasors and Positive/Negative Sequence Analysis

phasors and sequence analysis.jpg

Harmonics around 4 kHz Switching Frequency

switching frequency harmonics.jpg

Voltage (solid line) and Current (dashed) Harmonics around 60 Hz Fundamental

fundamental voltage and current harmonics.jpg

White Paper

Read the New White Paper on this Open-Source Circuit Design: 3-Phase Back-to-Back Inverter Research Board with NI Multisim and the NI GPIC


I would like to thank the talented NI engineers who are developing this open source inverter research board, as well as key contributors from various academic and industry groups. In particular, I would like to thank Dr. Kalyan K. Sen for his feedback and suggestions, author of Introduction to FACTS Controllers: Theory, Modeling, and Applications (IEEE Press Series on Power En...

Message 1 of 10

This is really nice development! I really got a lot of very helpful infomation. But just one question: I did not find the co-simulation example of this back-to-back converter. Do not you include it in NI Power Electronics Design Guide or you provided it but I did not find it?

PS: i am doing a research topic with somehow the same topology with this back-to-back converter and I used matlab&simulink for simulation, but I am planning to use c-RIO as the controller, therefore I want to learn to use the co-simulation methods of this converter using FPGA-VI and a mutisim model....

0 Kudos
Message 2 of 10

Good question. Here is a Multisim schematic suitable for co-simulation that matches the back-to-back inverter board.

Below it is shown in the "Standalone & Physical I/O" variant. If you run it in Multisim in this mode, a Multisim block generates the 3-phase sine-triangle PWM signals. An AC-induction motor is hooked up to Inverter A.

3-Phase Back-to-Back Inverter.jpg

To run it in a co-simulation with LabVIEW, change the schematic to the "Co-Simulation" variant. This greys out and disables the Multisim PWM generator, Precharge Contactor Control and Grid Sinewave components. I highlighted the box where you can change which variant is active in the screenshot below.

Back-to-back inverter - co-sim mode (variant box highlighted).png

If you don't see the toolbars for the Design Toolbox (containing the variant manager) and LabVIEW Co-Simulation Terminals like in my screenshot, go to the View menu to enable them, as shown below.

Enable Toolboxes.png

Below you can see a Multisim standalone simulation run, including the first 0.1 seconds when the precharge contactor is open, and then the induction motor spins up to reach a stable speed of 89.1 rad/s. The mechanical torque load on the induction motor can be controlled using the A key (to increase) or Shift-A (to decrease). In this case the mechanical load torque is 0.1 N*m. If you increase the load torque, the motor slows down, the amount of slip increases and therefore the current increases.

back-to-back inverter - standalone simulation run (0.1 Nm torque load).png

You can download this Multisim schematic here.

You can expect a full co-simulation example to be added to the Power Electronics Design Guide at a future date.

0 Kudos
Message 3 of 10

Congratulations with the new developments. Very nice choice of the topology, should be useful for a large range of the applications.

I have a short comment on the filters at the input and the output of the converter. I believe there should be some sort of delta connection of the capacitors instead this asymmetric connection, where two of the caps are connected in parallel and there is not capacitance in between the top and bottom phases. Am I missing something?


0 Kudos
Message 4 of 10

For the NI GPIC back-to-back 3-phase inverter research board, is there a way that the outputs of Inverter A and Inverter B can be connected in parallel (to a transmission line) to supply a load? A related quesiton is: can the output of the inverter be connected to the grid?


0 Kudos
Message 5 of 10

I would like to get hold of a research board. What options do I have? As far as I understood, I could:

  • Buy it from SVTronics using reference quote number 10112013A.
  • Buy it from Screaming Circuits.
  • Buy it from NI?
  • Or even modify the design starting from v28 and commission the work to some other PCB manufacturer.

Am I missing any options? Is v28 the latest version of the design? I'm in Europe, in case that needs to be considered. Thanks!

0 Kudos
Message 6 of 10

Hello dfjuggler,

Bloomy currently has the NI GPIC back-to-back 3-phase inverter research boards available for shipment.  Please contact Dawn Hamel at 508-281-8288 for details.

Best regards,

Jonathan P. Murray

Busuniess Unit Manager, Bloomy Energy

0 Kudos
Message 7 of 10

Thank you Jonathan, I will. Could I have an email address? That would be more convenient.

0 Kudos
Message 8 of 10

Here is full contact info for Dawn Hamel at Bloomy Controls.

Dawn Hamel | Buyer-Strategic Sourcing | Bloomy Controls Inc.

O: 508-281-8288 | F: 508-281-8295 | dawn.hamel@bloomy.com | www.bloomy.com

Note that Bloomy only handles orders for North America. If you are located outside the U.S./Canada/Mexico, please order from SVTronics by contacting Angela Dodd using the contact information below.

Angela Dodd


Tel: 214.440.1234 x110

Cell: 972-814-1485

Fax: 214.440.1222

3465 Technology

Plano, TX. 75074


Finally, always be sure to request a 93 mil or thicker PCB when ordering GPIC mating boards for mechanical strength reasons.

0 Kudos
Message 9 of 10

Hello BMac,

I am actually trying to load your file of the AC induction motor. While doing so, it gives me an error of missing starsim files related to the induction motor. Also after ignoring those files, in the end it give me error of missing the PI file and the starsim files.

I am attaching a picture of the error messages in the end. Kindly let me know of how to proceed with this issue at the earliest.

Thank you and regards,

Ammar Quaid Surti

California State University, Northridgeunnamed.png

0 Kudos
Message 10 of 10