Development of a new soft ferrite core for power applications

High frequency manganese-zinc ferrite was prepared by oxide ceramic process. The microstructure of representative samples was analyzed by scanning electron microscope (SEM). In addition, the resistivity (p) of samples was tested by YY2812 LCR meter and the magnetic properties were obtained by SY-8232 B-H Analyzer. In combination with the microstructure analysis of material, the effects of SnO 2 additive in MnZn ferrite were investigated, especially on initial permeability (μ i ), resistivity (p), hysteresis loss (P h ), eddy current loss (P e ) and residual loss (P r ). The results show that the amount of SnO 2 additive has an obvious influence on the microstructure and electromagnetic properties of the proposed material, such as μ ι , p, P h , P c and P r . There is an optimum content of SnO 2 which is 0.1% to ensure finer microstructure and lower loss at the frequency of 1MHz.

Co2O3 and SnO2 doped MnZn ferrites for applications at 3–5 MHz frequencies

Analysis and experiment of eddy current loss in Homopolar magnetic bearings with laminated rotor cores

This paper describes the method used at the Electrical Testing Laboratories for measuring the dielectric power losses in 10-foot samples of three-conductor cables with three-phase potential applied to the cable. The difficulties encountered and the methods employed to overcome them are discussed in considerable detail. Typical results are given in the form of data for two specimens of cable, one having a low power loss in the dielectric and one having a high power loss in the dielectric. The data are also presented in the form of curves. The discussion includes: (a) The theory of excessive internal dielectric loss as accounting for cable failures at local ``hot spots.'' (b) The advantages of plotting data with logarithmic scales. (c) A comparison of results obtained by computation from single-phase measurements with those obtained by direct measurement with three-phase potential. The conclusions drawn are: (a) The power loss in the dielectric in a three-conductor cable under actual three-phase conditions can be readily measured in the laboratory with specimens ten feet long. (b) No special apparatus is necessary for such measurements other than a reflecting high sensitivity wattmeter. (c) Apparently the power loss in the dielectric cannot in all cases be accurately calculated from data obtained in single-phase tests although it is highly probable that for all practical purposes the discrepancy would not be serious.

The low frequency power loss of two 1200V planar gate field-stop insulated gate bipolar transistor (IGBT) devices with different power rating is measured with double pulse test method. The switching loss and saturation loss with various collector current values are analyzed. The results show that power loss is strongly correlated with the device area and collector current. Device temperature is 6.6K lower for large area device when operating with collector current at 10A. The saturation power loss and turn-off trailing loss are discussed as well. Finally, the methods for power loss reduction are discussed from the standpoint of device structural design, layout optimization and manufacturing process.

Ba2Co2Fe12O22 (Co2Y, 0 wt%, 2 wt%)-added Ni0.8Zn0.2Fe2O4 polycrystalline ferrites are prepared by solid-state reaction method, and the magnetic properties of ferrites are investigated. Magnetic measurements show that the magnetic loss is obviously decreased with Co2Y addition. Loss separation reveals that both hysteresis loss and eddy current loss reduce significantly after Co2Y addition. The mechanism of magnetic loss decreasing due to Co2Y additive is discussed, and the decrease of magnetic hysteresis loss and eddy current loss caused by Co2+ cation doping was regarded as the main reason for the observed power loss decrease in ferrites and insulating grain boundary composed by barium compound which plays a role in decreasing eddy current loss. The Q value of Co2Y-added Ni0.8Zn0.2Fe2O4 ferrite was much higher than that of Ni0.8Zn0.2Fe2O4 sample which can be used as inductors for high-frequency applications.

This paper investigates the interdependence of hysteresis and eddy-current losses in magnetic cores. Based on the results of a numerical model developed for the analysis, the magnetodynamic loss phenomena are found to be distinctly interdependent. Because of the effects of eddy currents on the flux distribution in the lamination depth, hysteresis and excess losses show a dependence on eddy currents, and hence, on the excitation frequency. Eddy-current and excess losses, on the other hand, are affected by the magnetic characteristics of the material where hysteresis plays the role of a damper. An application of the model to a rotating electrical machine has showed that the interdependence between the losses is quite significant.

Distribution system represents the final link between bulk power system and the consumers. Distributed generators or small-scale energy sources are usually smaller than central energy sources and can produce electricity in the range of 10 kW to 10,000kW. It is usually connected to the power system points close to the customer. Power loss in a distribution system consists of real and reactive power loss. Real power loss is due to the transmission lines resistance while reactive power loss is due to the inductive element, which allows the real power transfer in the distribution system. This paper presents the optimal allocation and sizing of multi-distributed generation (DG) in distribution system for minimum power loss. The study involves the development of Gravitational Search Algorithm (GSA) engine as an optimization technique. Comparison with respect to Evolutionary Programming (EP) was conducted in order to highlight its superiority. The developed algorithm has been validated on 15-Bus IEEE Distribution System and the results revealed that power loss is reduced. GSA outperformed EP in terms of achieving lower minimal power loss.

Mechanism of Core Loss and the Grain-Boundary Structure of Niobium-Doped Manganese–Zinc Ferrite

Chapter 6 - 6.1 Magnetic Ceramics

Analysis of losses in NiO doped MnZn ferrites

Loss Simulation by Finite Element Magnetic Field Analysis Considering Dielectric Effect and Magnetic Hysteresis in EI-Shaped Mn-Zn Ferrite Core

The need for energy has significantly increased in the world in recent years. Various research works were presented to develop Renewable Energy Sources (RESs) as green energy Distributed Generations (DGs) to satisfy this demand. In addition, alleviating environmental problems caused by utilizing conventional power plants is diminished by these renewable sources. The optimal location and size of the DG-RESs significantly affect the performance of Radial Distribution Systems (RDSs) through the fine bus voltage profile, senior power quality, low power losses, and high efficiency. This paper investigates the use of PV (photovoltaic) and (Wind Turbine) WT systems as a DG source in RDSs. This investigation is presented via the optimal location and size of the PV and WT systems, which are the most used DG sources. This optimization problem aims to maximize system efficiency by minimizing power losses and improving both voltage profile and power quality using White Shark Optimization (WSO). This algorithm emulates the attitude of great white sharks when foraging using their senses of hearing and smell. It confirms the balance between exploration and exploitation to discover optimization that is considered as the main advantage of this approach in attaining the global minimum. To assess the suggested approach, three common RDSs are utilized, namely, IEEE 33, 69, and 85 node systems. The results prove that the applied WSO approach can find the best location and size of the RESs to reduce power loss, ameliorate the voltage profile, and outlast other recent strategies. Adding more units provides a high percentage of reducing losses by at least 93.52% in case of WTs, rather than 52.267% in the case of PVs. Additionally, the annual saving increased to USD 74,371.97, USD 82,127.257, and USD 86,731.16 with PV penetration, while it reached USD 104,872.96, USD 116,136.57, and USD 155,184.893 with WT penetration for the 33, 69, and 85 nodes, respectively. In addition, a considerable enhancement in the voltage profiles with the growth of PV and WT units was confirmed. The ability of the suggested WSO for feasible implementation was validated and inspected by preserving the restrictions and working constraints.

Wide bandgap (WBG) semiconductors including gallium nitride (GaN) and silicon carbide (SiC) offer significant performance improvement compared with conventional silicon power devices. The quasi-Z-source cascaded multilevel inverter (qZS-CMI) provides many advantages over the conventional CMI while applied in photovoltaic (PV) systems. In this paper, two solutions are proposed and compared to the design goal of a high efficiency and low-cost qZS-CMI based 1 MW/11 kV PV system. The first solution is based on 650 V GaN enhancement mode high-electron-mobility transistors (E-HEMT) and 650 V SiC Schottky diodes. The second solution uses 1200 V SiC power modules and 1200 V SiC Schottky diodes. The power losses and costs of the two candidate designs are compared in details. It is concluded that the first solution shows lower power losses and costs per quasi-Z-source inverter (qZSI) module. However, due to the low voltage rating of GaN E-HEMTs, more qZSI modules are needed to achieve the overall 11 kV inverter rating. Therefore, the second solution shows lower total power loss and cost in the medium-voltage, MW-scale qZS-CMI PV system.

Preparation and magnetic properties of high DC-bias performance Fe-Si-Nb-B-Cu/carbonyl iron chip inductors