Integrated motor drives: state of the art and future trends

With increased need for high power density, high efficiency and high temperature capabilities in Aerospace and Automotive applications, Integrated Motor Drives (IMD) offers a potential solution. However, close physical integration of the converter and the machine may also lead to an increase in components temperature. This requires careful mechanical, structural and thermal analysis; and design of the IMD system. This paper reviews existing IMD technologies and their thermal effects on the IMD system. The effects of the power electronics (PE) position on the IMD system and its respective thermal management concepts are also investigated. The challenges faced in designing and manufacturing of an IMD along with the mechanical and structural impacts of close physical integration is also discussed and potential solutions are provided. Potential converter topologies for an IMD like the Matrix converter, 2-level Bridge, 3-level NPC and Multiphase full bridge converters are also reviewed. Wide band gap devices like SiC and GaN and their packaging in power modules for IMDs are also discussed. Power modules components and packaging technologies are also presented

Short-term and long-term variability of antenna position due to thermal bending of pillar monument at permanent GNSS station

The variability of daily site coordinates at permanent GNSS station is a sum of many disturbing factors influencing the actual satellite observations, data processing, and bias modelling. In the paper are analysed possibilities of monitoring the instability of GNSS antenna pillar monument by the independent observations using the precise inclination sensor. Long-term series from three different types of pillars show specific features in amplitude and temporal evolution of monument bending. Correlations with daily temperature and/or solar radiation changes were proved

Mathematical model and analysis of single-leg matrix converter

The paper deals with analysis and modelling of a new type of single-phase supplied AC/AC converter with two phase outputs. It consists of single-leg half-bridge matrix converter loaded by resistive-inductive load in series connection. There are two problems solved in the paper: a) creating of second output phase shifted by 90 degrees against original one, and b) providing of frequency control of both orthogonal phase systems able supplying a two-phase electrical machine. As simulation results are given: harmonic analysis of the voltage of both phases; maximal possible reachable current waveform under R-L load with parametric changes of the time constant of the load. The simulation is resulting to recommendation for fair and right design of the converter, and demands to single- or two phase input supply voltage, respectively, under passive R-L or motoric load

Identification and Fragmentation of Cefalosporins, Lincosamides, Levofloxacin, Doxycycline, Vancomycin by ESI-MS

The aim of the paper is the identification of the most frequently used antibiotics such as cefazolin, cefuroxime, cefotaxime, ceftriaxone, ceftazidime, lyncomycin, clindamycin, levofloxacin, doxycycline and vancomycin by electrospray ionization mass spectrometry interface in positive and negative modes. The fragmentation pathways of the group of antibiotics were colligated on the basis of the obtained ESI mass spectra. Generally, the positive ion spectra of antibiotics are higher in intensity including an [M+H]⁺ ion and producing less fragmentation as well as more informative compared to the negative ion spectra. Only ESI of levofloxacin in positive and negative modes with the chosen tune parameters leads to degradation of molecular ion, so the parent ion does not appear in the mass spectra. The group of antibiotics (cephalosporins and lincosamides) shows the same characteristic fragmentation. These setup parameters were successfully applied for the routine determination of antibiotics in their pharmaceutical dosage forms and other objects. Data base was developed for identification of antibiotics by comparison of their molecular and fragment ions