Time Delay Identification Method of Wind Turbine Drivetrain Test Bench Based on Instability Characteristics Observation

Abstract

There is a huge difference in rotational inertia between the wind turbine drivetrain test bench (WTDTB) and the actual wind turbine, which needs to be accurately compensated. As a closed-loop control system with time delay, WTDTB working in the inertia simulation mode is prone to instability. The existing researches solve this problem by the time delay stability control algorithm based on high-order filter, which is on the premise that the filter order and the time delay order of the inertia compensation loop accurately match. However, the torque command response method currently used to measure time delay is not effective in practical applications. In order to accurately obtain the time delay, this paper draws on the idea of soft measurement based on operation parameters, finds and proves that there is a definite quantitative relationship between the compensation torque oscillation period and the time delay. On this basis, a time delay identification method based on instability characteristics observation is proposed. This method causes the controlled oscillation of the test bench by reasonably designing the oscillation experiment, extracts the oscillation period, and determines the time delay accordingly. The experiment results based on 15kW WTDTB verify the feasibility and effectiveness of the proposed method.