The modular architecture of a real-time-test program lets wind-turbine engineers automate the task of verifying many control ideas by including hardware components in their test loop. That includes embedded-control software for wind turbines. To write the program, Siemens wind-turbine engineers selected NI TestStand, LabVIEW Real-Time, LabVIEW FPGA modules, and the NI PXI platform, all from National Instruments, Austin, Texas, (ni.com). The test system now simulates the behavior of real wind-turbine components by running simulation models that supply simulated signals to the control hardware and software under test.
“The modular architecture let us scale-up the system to meet the growing requirements of a rapidly evolving industry,” says Siemens Testing and Control Software engineer Samir Bico. “The modularity and flexibility make it is easy to improve, adapt, and develop further. The system under test can be quickly swapped with another and without changes in the test-system architecture. Remote control and simple replications have the flexibility to copy the system to other sites as our operations expand.”
The testing task is no simple matter because the control system interfaces with many turbine components through hundreds of I/O signals and multiple communication protocols. The most complex part is the embedded control software executing the control loops.
Developers for the control software regularly release new versions for testing, to verify that the releases execute reliably. “With every software release we perform factory acceptance testing before the software can be used in the field. This new test system automates the process,” says Bico.
The previous and 10-year old test system was based on other software and PCI data acquisition boards. Its architecture and performance did not meet new requirements for test time and scalability. In addition, the system was difficult to maintain and had insufficient automation.
Wind turbines use many custom communication protocols because standards are few. “Using an NI PXI-7833R FPGA-based multifunction RIO module with the LabVIEW FPGA Module, lets us interface with and simulate these protocols. In addition, we are using the device to simulate magnetic sensors and for accurate three-phase voltage and current simulations. Another FPGA board connects to an NI 9151 R Series expansion chassis to further increase the system channel count,” says Bico. WPE
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