Conditions for Recurrence of a Flow of Physical Events with Unextendable Dead Time Period

2016 ◽  
Vol 58 (12) ◽  
pp. 1859-1867
Author(s):  
L. A. Nezhel’skaya
Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 698 ◽  
Author(s):  
Chen Wei ◽  
Xibo Yuan ◽  
Juan Zhou ◽  
Kangan Wang ◽  
Yonglei Zhang ◽  
...  

In low and medium voltage power conversion systems, multilevel converters are becoming more and more attractive due to improved power density. However, the complexity of topology and control is a big challenge for the application of multilevel converters. In this paper, a four-level (4L) hybrid flying capacitor (FC) T-type converter has been researched in detail. The topological advantage of the converter is displayed in comparison to existing four-level converters. According to the feature of the topology, the operating status has been analyzed and the reason for the voltage jump is researched in detail during the dead-time period. A strategy to reduce voltage jump by adjusting the switching states has be presented. The FC voltages can be balanced by selecting the appropriate switching states. The relationships between the fluctuations of FC voltages and the modulation index and power factor (PF) have been analyzed by simulation results. The performance of the 4L converter has been investigated in MATLAB/Simulink as well as on a down-scaled laboratory prototype.


Consider three independent Poisson processes of point events of rates λ 1 , λ 2 and λ 12 . There are two electronic counters, the first recording events from the first and third Poisson processes, and the second recording events from the second and third Poisson processes. Both counters have constant dead-time, i.e. following the recording of an event on a counter no further event can be recorded on that counter until the appropriate constant time has elapsed. Two ways of estimating λ 12 are via a coincidence rate, i.e. the rate of occurrence of pairs of events separated by less than a suitable small tolerance, and via the covariance of the numbers of events recorded on the two counters in a suitable time period. The theoretical values of these quantities are calculated allowing for dead-time. The techniques used illustrate the study of bivariate point processes.


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