Waveform control algorithm for rotational single sheet testers using system identification techniques

In rotational single sheet testers (RSST), the magnetic properties of electrical steel sheet are measured for well-defined one- or two-dimensional induction waveforms over a large frequency range (1–200 Hz). For this task, a new iterative waveform control algorithm is presented. It is based on the recursive least squares system identification technique. The modeling of the setup as well as the principles and implementation details of the algorithm are discussed. Simulation and measurement results for alternating sinusoidal magnetization of the sample are presented. The main advantage of the proposed method is that it does not require preliminary information concerning the properties of the tested material or the measurement setup. The method is therefore ideally suited for use in a fully automated measurement system. Furthermore, especially for low frequencies (1–10 Hz) the proposed algorithm exhibits faster convergence compared to previously described methods.