Showing 4 results for Inductance
H. Heydari, M. Rezaee,
Volume 6, Issue 4 (12-2010)
Abstract
The principle object of this paper is to offer a modified design of Rogowski coil based on its frequency response. The improvement of the integrator circuit for nullifying the phase difference between the waveforms of the measured-current and the corresponding terminal voltage is a further object of this investigation.
This paper addresses an accurate, yet more efficient measuring and protecting device for low frequency applications. This requires verification for the simulations by physical descriptions and experimental results. These validate the superior performance of Rogowski coils over conventional current transformers.
Keywords: current transformer, frequency response, integrator circuit, mutual inductance, Rogowski coil, terminal resistor
M. Jamali, M. Mirzaie, S. A. Gholamian,
Volume 7, Issue 3 (9-2011)
Abstract
The phenomenon of magnetizing inrush is a transient condition, which occurs primarily when a transformer is energized. The magnitude of inrush current may be as high as ten times or more times of transformer rated current that causes malfunction of protection system. So, for safe running of a transformer, it is necessary to distinguish inrush current from fault currents. In this paper, an equivalent instantaneous inductance (EII) technique is used to discriminate inrush current from fault currents. For this purpose, a three-phase power transformer has been simulated in Maxwell software that is based on finite elements. This three-phase power transformer has been used to simulate different conditions. Then, the results have been used as inputs in MATLAB program to implement the equivalent instantaneous inductance technique. The results show that in the case of inrush current, the equivalent instantaneous inductance has a drastic variation, while it is almost constant in the cases of fault conditions.
M. Samami, H. Yaghobi, M. Niaz Azari,
Volume 13, Issue 2 (6-2017)
Abstract
This investigation deals with a mathematical model for a distribution transformer including saturation effect. To this end, the equations related to a three phase transformer are specified and the effect of an inter-turn fault is included. Naturally by applying an inter-turn fault the inductance and resistance matrix will change. Thus, unknown quantities of inductances and resistances for completing the matrix are calculated and the inputs, outputs and state variables are specified. All the equations will be rewritten in terms of state variables, subsequently saturation effect is added to the model. Finally the block diagram of the specified model based on the obtained equations are designed and the ultimate model is simulated. The saturation effect, added to the mathematical model and also the variable fault parameters are known as two significant contributions which distinguish this study from other investigations. Various results obtained from the simulation of the final model confirm the changes in the behavior of faulty transformer such as: a large circulating current flowing in the shorted turns, lower impact on terminal voltages and currents, a sudden increase in current flowing in the primary winding, asymmetrical flux distribution and inverse proportion of the fault severity and the limiting resistor.
D. Kishan, P. S. R. Nayak, B. Naresh Kumar Reddy,
Volume 16, Issue 1 (3-2020)
Abstract
In recent years, the popularity of wireless inductive power transfer (WIPT) system for electric vehicle battery charging (EVBC) is always ever-increasing. In the WIPT inductively coupled coil structure is the heart of the system and the mutual inductance (MI) between the coupled coils is the key factor for effective power transfer. This paper presents the analysis of mutual inductance between the spiral square coils based on the cross-sectional area ratio of spiral circular and spiral square coupled coils. The analytical computed MI values are compared with FEM (Ansys Maxwell) simulation and Experimental computed values. Finally, the designed spiral square coils are implemented in a laboratory prototype model and at the receiver side for effective electric vehicle (EV) battery charging a closed-loop PID controller is implemented for DC-DC buck converter. The effectiveness of the proposed controller has been tested by providing sudden changes in mutual coupling and change in reference value. The proposed system is suitable for both stationary and dynamic wireless EVBC.
