Closed-Loop Control for a Rotational Core Loss Tester

In this paper, a flux density waveform controller is proposed for core loss measurements under rotating magnetic fields in the electrical steel. It is based on a vector control scheme in the synchronous dq reference frame. The proposed dq vector controller eliminates the need of commonly used harmonic compensation techniques; improving the execution and convergence times of the controller. Furthermore, it eliminates the need of filters and transformer isolators, which further reduces delays, thus improving the system's dynamic response. The performance of the controller is analyzed using simulations and validated experimentally. The proposed controller is experimentally shown to control the magnetic flux waveforms within 2% of the reference flux density signals at very high densities (up to 1.9 T) under sinusoidal conditions, and up to 1.2 T under nonsinusoidal conditions.