Variable Frequency Starter Generator Testbed

Vishwa

Introduction:
A VFSG (Variable Frequency Starter Generator) is a subsystem that consist of several components; main synchronous generator, motor that serves as a starter and/or exciter for the generator, rectifier stage, and generator control unit that provides regulation. Typically, one or two VFSGs are mounted on each turbine and connected through a gearbox. The VFSGs perform two primary functions: electric starting of the main engines and, once the engine is started, providing electric power to the airplane. This design example, illustrates a testbed to verify behavior of a VFSG and to exercise proper operation versus dynamic loading effects. To demonstrate VFSG simulation, a sub-system model is assembled that includes all primary components. The test circuit is simulated for 2 seconds. The VFSG main generator is started up under no-load conditions, and a 10 Ohm load is applied at 1.25 seconds for a short duration using a simple 3-phase switch. The objective of this exercise is to observe the in-rush behavior upon start-up and upon sudden load application and observe main generator slip into saturation, and reaction of GCU with respect to its maximum current limitation.

Circuit Snapshot:
Refer to the attached snapshot "vfsg_design.png".

How To Use:
Prerequisite for simulating this example in SaberRD:
The design uses customized models and this library of models has to be imported and compiled before running the simulation.
1. Download the attached library named aerospace_systems_2017_06_v2.zip to your local drive.
2. Launch SaberRD.
3. Open any sample design or create an empty design.
4. Import the downloaded library file aerospace_systems_2017_06_v2.zip from the local drive into SaberRD by using the “Import Library” option and compile the library.

Download and simulate the example in SaberRD:
1. Download the enclosed design zip file named Aerospace_Vfsg_Testbed.zip to your local drive.
2. Unzip the file.
3. Launch SaberRD.
4. Navigate to the directory where the unzipped files are available.
5. Open the file that has the extension, ".ai_dsn".
6. Follow the simulation instructions mentioned in the schematic.

For more details on the design, refer to README.pdf file in the design folder.

Note:
This example works only in SaberRD Commercial Edition.