Switching frequency selection for aerospace power converter system considering the design of output LC filter inductor optimizing weight and power loss

Author(s):  
Tharmini Thavaratnam ◽  
Chushan Li ◽  
David Xu
Electronics ◽  
2017 ◽  
Vol 6 (4) ◽  
pp. 110 ◽  
Author(s):  
Saher Albatran ◽  
Issam Smadi ◽  
Hamzeh Ahmad ◽  
Ahmed Koran

Genetics ◽  
1980 ◽  
Vol 94 (4) ◽  
pp. 989-1000
Author(s):  
Francis Minvielle

ABSTRACT A quantitative character controlled at one locus with two alleles was submitted to artificial (mass) selection and to three modes of opposing natural selection (directional selection, overdominance and underdominance) in a large random-mating population. The selection response and the limits of the selective process were studied by deterministic simulation. The lifetime of the process was generally between 20 and 100 generations and did not appear to depend on the mode of natural selection. However, depending on the values of the parameters (initial gene frequency, selection intensity, ratio of the effect of the gene to the environmental standard deviation, fitness values) the following outcomes of selection were observed: fixation of the allele favored by artificial selection, stable nontrivial equilibrium, unstable equilibrium and loss of the allele favored by artificial selection. Finally, the results of the simulation were compared to the results of selection experiments.


2013 ◽  
Vol 64 (3) ◽  
pp. 143-151
Author(s):  
Farid Bouchafaa ◽  
Mohamed Seghir Boucherit ◽  
El Madjid Berkouk

Voltage source multilevel inverters have become very attractive for power industries in power electronics applications during last years. The main purposes that have led to the development of the studies about multilevel inverters are the generation of output voltage signals with low harmonic distortion; the reduction of switching frequency. A serious constraint in a multilevel inverter is the capacitor voltage-balancing problem. The unbalance of different DC voltage sources of five-level neutral point clamping (NPC) voltage source inverter (VSI) constitutes the major limitation for the use of this new power converter. In order to stabilize these DC voltages, we propose in this paper to study the cascade constituted by three phases five-level PWM rectifier, a clamping bridge and five-level NPC (VSI). In the first part, we present a topology of five-level NPC VSI, and then they propose a model of this converter and an optimal PWM strategy to control it using four bipolar carriers. Then in the second part, we study a five-level PWM rectifier, which is controlled by a multiband hysteresis strategy. In the last part of this paper, the authors study shows particularly the problem of the stability of the multi DC voltages of the inverter and its consequence on the performances of the induction motors (IM). Then, we propose a solution to the problem by employed closed loop regulation using PI regulator type fuzzy logic controller (FLC). The results obtained with this solution confirm the good performances of the proposed solution, and promise to use the inverter in high voltage and great power applications as electrical traction.


2020 ◽  
Author(s):  
Angelica Paula Caus ◽  
Guilherme Martins Leandro ◽  
Ivo Barbi

This paper presents a new power converter topology<br>generated by the integration of the asymmetrical ZVS-PWM dcdc converter with a switched-capacitor ladder-type commutation<br>cell. Circuit operation and theoretical analysis with emphasis on<br>the soft-commutation process are included in the paper. The<br>main advantage of the proposed converter with respect to the<br>conventional asymmetrical half-bridge dc-dc converter is the<br>reduction of the voltage stress across the power switches to the<br>half of the input dc bus voltage, enabling the utilization of lower<br>voltage rating components. Experiments conducted on a<br>laboratory prototype with 1.4 kW power-rating, 800 V input<br>voltage, 48 V output voltage and 100 kHz switching frequency<br>are included, to verify the theoretical analysis and the design<br>methodology. The maximum efficiency of the experimental nonoptimized prototype was 93.6%.<br>Index Terms - Asymmetrical dc-dc converter, pulse-widthmodulation, switched-capacitor, zero voltage switching.<div><br><br></div>


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