Technical Library | 2019-11-07 08:59:14.0
Inductors realized with high permeable MnZn ferrite require, unlike iron-powder cores with an inherent dis-tributed gap, a discrete air gap in the magnetic circuit to prevent saturation of the core material and/or tune the inductance value. This large discrete gap can be divided into several partial gaps in order to reduce the air gap stray field and consequently the proximity losses in the winding. The multi-gap core, realized by stacking several thin ferrite plates and inserting a non-magnetic spacer material between the plates, however, exhibits a substan-tial increase in core losses which cannot be explained from the intrinsic properties of the ferrite. In this paper, a comprehensive overview of the scientific literature regarding machining induced core losses in ferrite, dating back to the early 1970s, is provided which suggests that the observed excess core losses could be attributed to a deterioration of ferrite properties in the surface layer of the plates caused by mechanical stress exerted during machining.
Technical Library | 2019-10-30 23:46:39.0
This work presents the fabrication of embedded inductors and the experimental laser machining of gaps in the underlying ferrite structure. (...) Energy efficiency is a major driver in the evolution of electronics and electronics packaging. To manage power consumption, portable appliances (smartphones, tablets, e-readers etc.) often use multiple supply voltages and DC/DC converters. Most are based on switch mode power conversion (SMPC). In a power converter, inductors and transformers are used to temporarily store energy during switching cycles. They also have the function of filtering noise. The power magnetics are often the largest and most expensive devices in the circuit. Integrating the magnetics into either a power converter module or system board can significantly reduce size and cost of the power converter function.
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