Inductor

About: Inductor is a research topic. Over the lifetime, 52565 publications have been published within this topic receiving 484068 citations. The topic is also known as: passive two terminal.

Experimental evaluation of the influence of DC-premagnetization on the properties of power electronic ferrites

Abstract: In many power electronic applications, ferrite cores of magnetic components are biased with a DC or low-frequency premagnetization. Usually however, the influence of the bias on the losses and permeability is not considered in the component design. This paper describes a precise measurement setup to determine the power losses and the magnetization curve of premagnetized ferrites. The measurements on typical ferrites of two major manufacturers prove that the influence of a DC-bias on the material properties cannot be neglected.

Switched Z-Source/Quasi-Z-Source DC-DC Converters With Reduced Passive Components for Photovoltaic Systems

Abstract: In this paper, switched Z-source/quasi-Z-source dc-dc converters (SZSC/SQZSCs) are proposed for the photovoltaic (PV) grid-connected power system, where the high step-up dc-dc converters are required to boost the low voltage to high voltage. The boost factor is increased by adding another one switch and diode to the output terminals of traditional Z-source/quasi-Z-source dc-dc converters. Not only does the output capacitor function as the filter capacitor; it is also connected in series into the inductors' charging loops when both switches are turned on. Compared with existing Z-source based structures, higher boost factor is realized through a small duty cycle (smaller than 0.25). On the one hand, the instability caused by the saturation of the inductors can be avoided. On the other hand, a larger range can be reserved for the modulation index of the backend H-bridge when they are used for the dc-ac conversion. Moreover, much fewer passive components are employed when compared with the recently proposed hybrid 3-Z-network topologies that have the same voltage gain, which can enhance the power density and decrease the cost. The performances of the proposed converters, including their operational principles in continuous and discontinuous current modes, voltage and current parameters of components, and impacts of parasitic parameters, are analyzed. The simulation and experimental results are given to verify the aforementioned characteristics and theoretical analysis.

Discharge lamp driving circuit

Abstract: A circuit for operating a discharge lamp at a low frequency AC voltage while repetitively interrupting at a high frequency the voltage component to be applied to the lamp. The circuit includes at least one switching transistor for repetitively interrupting the voltage to be applied to the lamp at the high frequency, for example, 40 KHz so as to allow the use of a light and less bulky inductor as the current limiting conductor to be connected in series with the lamp. A bridge inverter is provided to have at least one pair of switching transistors for alternately reversing a DC voltage to apply the resulting AC voltage to the lamp at the low frequency, for example, 100 Hz low enough to stably operate the lamp without suffering from acoustic resonance. The high frequency component is bypassed through a bypass capacitor connected in parallel with the lamp. By reason of the inverter producing the low frequency AC voltage, the circuit requires all-off period during which the switching transistors of the bridge inverter are simultaneously off for preventing the short circuiting of the power source. An oscillation-inducing inductor is connected in series with the lamp in parallel relation to the bypass capacitor so as to form a series oscillating circuit which causes to flow an alternating oscillating current to the lamp circuit throughout the all-off period. The resulting oscillating lamp current continues for a longer time to thereby retard the deionization of the lamp. Accordingly, the all-off time can be extended to such an extent as to give greater flexibility in designing the circuit which is free from short circuiting of the power source as well as from the increased reignition voltage.

Iron loss analysis of Mn-Zn ferrite cores

Abstract: Iron loss measurements of Mn-Zn ferrite cores up to the megahertz range are reported. Taking the dc magnetic hysteresis, the eddy, and displacement currents into account, magnetic and electric field distributions in the cores are computed with the cylindrical coordinates and Bessel functions. The computed iron loss due to the magnetic and electric fields is compared with the experimental value at different exciting frequencies. It is noted that the computed iron loss becomes considerably smaller than the experimental at high frequencies. In order to explain the difference between the computed and experimental iron losses, a new magnetic field component yielding a dynamic magnetic loss is assumed and added to the magnetic field intensity of the dc magnetic hysteresis. This assumption is verified by evaluating the iron losses in different size cores composed of the same ferrite material. Displacement current distribution in a ferrite core depends on the cross-sectional area of the magnetic flux path, which brings about the dependence of the frequency characteristics of the iron loss upon core size.

Modeling the dynamics of nonlinear inductor circuits

Abstract: The Jiles-Atherton (J-A) model is applied to the problem of describing the dynamics of a nonlinear circuit driven by a square wave voltage source and comprising a linear resistor and capacitor in series with a nonlinear inductor, whose core displays saturation and hysteresis. The presence of hysteresis is shown to increase the order of the circuit by one. Period-multiplication and chaos are observed and excellent agreement is obtained between experiment and simulation. >