A pulse hysteresisgraph system was constructed capable outputting current source and voltages source waveforms. MATLAB scripts were created to analyze the collected data. Three toroidal samples of soft magnetic materials were prepared. Theoretical modeling was done to predict the variation of effective applied magnetic fields inside the toroids from ideal assumptions due to three effects: wire spacing, cylindrical spreading, and eddy current generated fields. Data was collected under sinusoidal voltage source and sinusoidal current source excitation at 1 kHz. Large differences in core loss were noted especially at higher field excitations. Core loss under sinusoidal current source excitation was found to always be greater than or equal to core loss under sinusoidal voltage source. Normal magnetization curves under sinusoidal current and voltage source excitation were also compared. Significant differences were apparent in the magnetization curves of one sample toroid, and slight differences noted in the curves of the other two samples. Eddy currents were offered as a primary mechanism for the difference in core loss between sinusoidal current source and sinusoidal voltage source. A formula to predict the relative eddy current losses to be expected from an arbitrary, periodic voltage waveform shape is given. / text

Closed loop Hall-effect current sensors used in power electronic applications require high bandwidth and small transient errors. For this, the behaviour of a closed loop Hall-e ect current sensor is modeled. Analytical expression of the step response of the sensor using this model is used to evaluate the performance of the PI compensator in the current sensor. Based on this expression a procedure is proposed to design parameters of the PI compensator for fast dynamic performance and for small transient error. A prototype closed loop Hall-effect current sensor is built in the laboratory. A PI compensator based on the procedure devised earlier is designed for the sensor. A power electronic converter based current source is designed and fabricated in the labo-ratory for validation of steady state and transient performance of Hall-effect current sensors. A novel hardware topology is proposed, using which the same hardware set-up can produce both step current and sinusoidal current in its designated sections without any modi cation in the hardware con guration. It produces step current of controlled peak value upto 100A and controlled rate of change with both positive and negative dtdi . The step transition time is less than 200ns. The dtdi is adjustable upto a limit of 300A/ s to verify the dtdi following capability of the sensor. The same current source produces continuous sinusoidal current of controlled magnitude upto 75A peak and controlled frequency from 1Hz to 1000Hz. The magnitude and the frequency of the sinusoidal current can be varied on-line like a voltage function generator. The hardware of the current source is designed to consume minimal ac-tive power from mains during continuous sinusoidal current generation. This current source is used in experimental veri cation of the steady state and the transient performance of the designed laboratory current sensor. The transient performance of the laboratory current sensor is observed to be superior to state-of-the-art commercial current sensors available for power electronic applications.