Closed loop control for a rotational core loss tester

This paper proposes a flux density waveform controller based on vector control in the synchronous dq reference frame for core loss measurements under rotating magnetic fields. The proposed dq vector controller eliminates the need for realtime Fourier series based harmonic compensation caused due to the electrical steel non-linearity, improving the execution and convergence times of the controller. Furthermore, it eliminates the need for filters and transformer isolators, which further reduces the delays, thus improving the system response. The performance of the controller is analysed 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 intensities (up to 1.9 T) under sinusoidal conditions, and up to 1.2 T under non-sinusoidal conditions.