Biblio

In this paper, we use selective laser melting (SLM) technology to fabricate AlNiCo magnetic materials, and the effects of laser processing parameters on the density and mechanical properties of AlNiCo magnetic materials were studied. We tested the magnetic properties of the heat-treated magnets. The results show that both laser power and scanning speed affect the forming. In this paper, the influence of laser power on the density of samples far exceeds the scanning speed. Through the experiment, we obtained the optimal range of process parameters: laser power (150 170W) and laser scanning speed (800 1000mm/s). Although the samples formed within this range have higher density, there are still many cracks, further research work should be done.

Permanent magnet synchronous motors (PMSM) are widely used in the shafts of industrial robots. The quality consistency of PMSM, derived from both the wide range of operating temperature and inherent uncertainties, significantly influences the application of the PMSM. In this paper, the mechanism of temperature influence on the PMSM is analyzed with the aid of the digital model, and the quantitative relationship between the main PMSM feature, the cogging torque, and the temperature is revealed. Then, the NdFeB remanence in different temperature levels was measured to obtain its temperature coefficient. The finite element method is used to simulate PMSM. The qualitative and quantitative conclusions of cogging torque drop when the temperature rises are verified by experiments. The magnetic performance data of the magnetic tiles of 50 motors were randomly sampled and the cogging torque simulation was carried out under the fixed ambient temperature. The results show that the dispersion significantly increases the stray harmonic components of the cogging torque.

This paper proposes a novel kind of direct-current and alternate-decay-current hybrid integrative magnetization and demagnetization power supplies applied to transformer dc bias treatment based on a nanocomposite magnetic material. First, according to the single-phase transformer structure, one dc bias magnetic compensation mechanism was provided. The dc bias flux in the transformer main core could be eliminated directionally by utilizing the material remanence. Second, for the rapid response characteristic of the magnetic material to an external magnetic field, one positive and negative dc magnetization superimposed decaying ac demagnetization hybrid integrative power supplies based on single-phase rectifier circuit and inverter circuit was designed. In order to accurately control the magnetic field strength by which a good de/-magnetization effect could be achieved, this paper adopts the double-loop control technology of the magnetic field strength and magnetizing current for the nanocomposite magnetic state adjustment. Finally, two 10 kVA transformers and the experiment module of the hybrid integrative power supplies were manufactured and built. Experimental results showed that the integrated power supplies have good de/-magnetization effect and practicability, proving the validity and feasibility of the proposed scheme.

An improved current transformer model (CT) developed in DIgSILENT™ is presented in this paper. The hysteresis characteristics of magnetic material described by Jiles-Atheron theory are included. The results show that model can represent the saturation and remanence characteristics of CT core accurately. The model accuracy is verified by comparing the simulation results with PSCAD/EMTDC™.