The article presents results of tests performed at the AGH-University of Science and Technology in Cracow on strength of single-coil inductors used as tools in electrodynamic machining of pipes. The character of volumetric Lorentz forces acting on coils of compressing and expanding inductors was discussed, and numerically determined distributions of stresses and displacements created in coils under the impact of these forces were presented. The problems presented are relevant when designing durable inductors intended for industrial applications.
The aim of this paper is to present a new approach to the problem of silicon integrated spiral inductors modeling. First, an overview of models and modeling techniques is presented. Based on 3D simulations and published measurement results, a list of physical phenomena to be taken into account in the model is created and based on it, the spiral inductor modeling by frequency sampling method is presented. To verify the proposed method a test circuit, containing 6 spiral inductors was designed and integrated in a silicon technology. The parameters of the spiral inductors from the test circuit were next measured and compared with simulations results. The comparison for one of those six spiral inductors is presented in the article.
The purpose of this paper is to propose a model of a novel quasi-resonant boost converter with a tapped inductor. This converter combines the advantages of zero voltage quasi-resonant techniques and different conduction modes with the possibility of obtaining a high voltage conversion ratio by using a tapped inductor, which results in high converter efficiency and soft switching in the whole output power range. The paper contains an analysis of converter operation, a determination of voltage conversion ratio and the maximum voltage across power semiconductor switches as well as a discussion of control methods in discontinuous, critical, and continuous conduction modes. In order to verify the novelty of the proposed converter, a laboratory prototype of 300 W power was built. The highest efficiency η = 94.7% was measured with the output power Po = 260 W and the input voltage Vin = 50 V. The lowest efficiency of 90.7% was obtained for the input voltage Vin = 30 V and the output power Po = 75 W. The model was tested at input voltages (30–50) V, output voltage 380 V and maximum switching frequency 100 kHz.
The aim of this paper is to derive an analytical equations for the temperature dependent optimum winding size of inductors conducting high frequency ac sinusoidal currents. Derived analytical equations are useful designing tool for research and development engineers because windings made of foil, square-wire, and solid-round-wire windings are considered. Temperature dependent Dowell’s equation for the ac-to-dc winding resistance ratio is given and approximated. Thermally dependent analytical equations for the optimum foil thickness, as well as valley thickness and diameter of the square-wire and solid-round-wire windings are derived from approximated thermally dependent ac-to-dc winding resistance ratios. Minimum winding ac resistance of the foil winding and local minimum of the winding ac resistance of the solid-round-wire winding are verified with Maxwell 3D Finite Element Method simulations.