Development of a 4 MW Full-Size Wind-Turbine Test Bench

The in-field validation of wind turbines (WTs) behavior is very time consuming and cost intensive, especially when fault ride-through tests are conducted. Full-size wind-turbine test benches allow a realistic operation of WTs in an artificial environment. Due to the independency of wind and grid conditions, the cost and duration of the test program and certification can be reduced. This paper presents the development of 4 MW full-size wind-turbine test bench following a multiphysics power hardware-in-the-loop concept. Different from other test facilities, the presented test bench utilizes a direct-drive prime-mover concept combined with a nontorqueload (NTL) unit to enable the application of highly dynamic stresses at the rotor hub and additionally a power-electronicsbased grid emulator. Through the measurement results of the test programs conducted on the test bench, the capability of the test bench in replicating the field conditions including voltage dips is demonstrated. In addition, a time consuming efficiency measurement can be performed with the reduced duration on the test bench. This shows another main benefit of the test bench compared to the conventional test method for WTs.