Simplified Mode Design of Micro Inductors 1

Recently, many literature have proposed the use of thin film magnetic materials to manufacture micro transformers, which has shown the potential to achieve miniaturization of power converters using microfabrication technology. The use of thin film microfabrication technology can produce extremely fine patterned structures that control eddy current losses, allowing the use of metal magnetic alloys below 20MHz. Metal magnetic alloys generally have high magnetic flux density and low hysteresis loss. Through design and specialized optimization, high efficiency and high power density can be achieved. A design method for distributed or quasi distributed gap inductors is shown in Figure 1, which can be used in power conversion circuits. Using pulse width modulation (PWM) buck converter as an example, its calculation method can also be applied to other converter structures.diode

Definition of Simplified Mode 2

Firstly, analyze the end turns, whose lateral width Slat needs to be close to the magnetic core, and the lateral spacing St between turns can be ignored (see Figure 1). The first step is to calculate the loss per unit area and the controlled power. Assuming that the magnetic field in the window area is in the horizontal direction, the AC loss in the winding can be estimated using one-dimensional analysis, as long as it is based on the ratio between the conductor height hc and the penetration depth δ e. It can be described by the AC resistance factor Fr (hc/δ c)=Rac/Rdc. For the current waveform, Fourier expression can be used to estimate the Frk factor for each important harmonic K.diode

If anisotropic NiFe alloy is used as the magnetic core, the main magnetic flux can often refer to the direction of the magnetization axis without hysteresis. Control eddy current losses and deposit stacked magnetic cores into multilayer films. Estimate the loss of important harmonics for each layer and magnetic flux density waveform, and add them together. When making this estimation, it is assumed that the magnetic flux density is parallel to each layer.diode