Simplified Predictive Duty Cycle Control of Multilevel Converters With Internal Identical Structure

In the aerospace industry where the weight and power density are important design parameters, high frequency operation results in smaller passive components. Furthermore, to achieve a large voltage conversion ratio, which is a goal for payload systems, the use of transformers increases the size and power losses of the system. To fulfill the space and weight requirements, a transformer-less SiC-based DC-DC multilevel converter providing high voltage conversion ratios without an extremely high duty cycle has been realized. The experimental high switching frequency and low current results for a conventional, 3-level and 4-level converter utilizing Si and SiC based COTS diodes are presented. SiC-based multilevel converters show a higher efficiency due to the low reverse recovery and fast switching of the diodes, which results in a higher voltage conversion ratio. This translates to a lower duty cycle to obtain the required output voltage, whilst eliminating the need for complex filtering even under light load conditions.

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New Optimized Control of Cascaded Multilevel Converters for Grid Tied Photovoltaic Power Generation

Journal Européen des Systèmes Automatisés ◽

10.18280/jesa.540512 ◽

2021 ◽

Vol 54 (5) ◽

pp. 769-776

Author(s):

Karima Benamrane ◽

Thameur Abdelkrim ◽

Benlahbib Benlahbib ◽

Noureddine Bouarroudj ◽

Abdelhalim Borni ◽

...

Keyword(s):

Duty Cycle ◽

Fuzzy Logic Controller ◽

Pulse Width Modulation ◽

Multilevel Converters ◽

Pi Regulator ◽

Duty Cycles ◽

Dc Bus ◽

Bus Voltage ◽

Two Stages

This paper proposes a new optimized control of photovoltaic two stages conversion cascade composed by Three Levels Boost (TLB) and Three Levels Neutral Point Clamped (TLNPC) inverter. In order to extract the maximum power from photovoltaic generator and get a balanced DC bus voltage, the duty cycles of the two TLB switches are determinate from a Fuzzy Logic Controller (FLC) for the first switch and by adding to the first duty cycle an additional duty cycle obtained by integration of the error between the two capacitors voltages of DC bus. Balancing the bus voltages by the TLB using a single regulator avoid us to use a complex balancing algorithm by the redundant vectors of TLNPC inverter. For the control of the inverter, we used a Proportional Integral (PI) regulator optimized by PSO. This command allows us to have on one side a constant DC bus voltage and a current injection in phase with the grid voltage. To have an efficient follow-up of the TLNPC inverter reference voltages, the Space Vector Pulse Width Modulation (SVPWM) is applied. The simulation is carried out in MATLAB/SIMULINK platform. The results obtained from the application of the FLC command associated with PI PSO are better compared to the simulation without optimization in terms of sum of the absolute values of the errors at the inputs of the three PI regulators.

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Two-photon excitation microscopy in cellular biophysics

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100136684 ◽

1995 ◽

Vol 53 ◽

pp. 62-63

Author(s):

David W. Piston ◽

Brian D. Bennett ◽

Robert G. Summers

Keyword(s):

Confocal Microscopy ◽

Laser Beam ◽

Duty Cycle ◽

Excited Electronic State ◽

Input Power ◽

Two Photon ◽

Simultaneous Absorption ◽

Photon Excitation ◽

Very High ◽

Two Photon Excitation

Two-photon excitation microscopy (TPEM) provides attractive advantages over confocal microscopy for three-dimensionally resolved fluorescence imaging and photochemistry. Two-photon excitation arises from the simultaneous absorption of two photons in a single quantitized event whose probability is proportional to the square of the instantaneous intensity. For example, two red photons can cause the transition to an excited electronic state normally reached by absorption in the ultraviolet. In practice, two-photon excitation is made possible by the very high local instantaneous intensity provided by a combination of diffraction-limited focusing of a single laser beam in the microscope and the temporal concentration of 100 femtosecond pulses generated by a mode-locked laser. Resultant peak excitation intensities are 106 times greater than the CW intensities used in confocal microscopy, but the pulse duty cycle of 10-5 maintains the average input power on the order of 10 mW, only slightly greater than the power normally used in confocal microscopy.

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Acoustic-Reflex Dynamics for Pulsed Signals

Journal of Speech and Hearing Research ◽

10.1044/jshr.2102.295 ◽

1978 ◽

Vol 21 (2) ◽

pp. 295-308

Author(s):

Terry L. Wiley ◽

Raymond S. Karlovich

Keyword(s):

Duty Cycle ◽

Acoustic Impedance ◽

Normal Hearing ◽

Broadband Noise ◽

Threshold Shift ◽

Temporary Threshold Shift ◽

Acoustic Reflex ◽

Stapedius Muscle ◽

Duty Cycles

Contralateral acoustic-reflex measurements were taken for 10 normal-hearing subjects using a pulsed broadband noise as the reflex-activating signal. Acoustic impedance was measured at selected times during the on (response maximum) and off (response minimum) portions of the pulsed activator over a 2-min interval as a function of activator period and duty cycle. Major findings were that response maxima increased as a function of time for longer duty cycles and that response minima increased as a function of time for all duty cycles. It is hypothesized that these findings are attributable to the recovery characteristics of the stapedius muscle. An explanation of portions of the results from previous temporary threshold shift experiments on the basis of acoustic-reflex dynamics is proposed.

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PENINGKATAN KEMAMPUAN GURU BAHASA INDONESIA DALAM MENYUSUN RENCANA PROGRAM PEMBELAJARAN (RPP) SDN 015 PAGARAN TAPAH DARUSSALAM MELALUI METODE PEMBERIAN TUGAS

Primary: Jurnal Pendidikan Guru Sekolah Dasar ◽

10.33578/jpfkip.v5i3.3956 ◽

2017 ◽

Vol 5 (3) ◽

pp. 713

Author(s):

Mukhlis '

Keyword(s):

Aspect Ratio ◽

Duty Cycle ◽

Lesson Plans ◽

Learning Program ◽

School Subjects ◽

Bahasa Indonesia

Based on the observation of some teachers found the symptoms as follows: the lack of abilityof Indonesian teachers in designing learning program (RPP), the learning device is only usedas a supplement and not to the needs of teaching, most teachers again if asked the lessonanswered not have or has not been made. The purpose of this research is to improve theability of Indonesian teachers in designing learning program (RPP) at SDN 015 PagaranTapah Darussalam through the method of administration tasks. This type of research is actionresearch school. Subjects in this study were teachers Indonesian as many as 12 people. Basedon the analysis and discussion can be concluded that the method of administration tasks canimprove the ability of Indonesian teachers in making learning device in SDN 015 PagaranTapah Darussalam through the method of administration tasks. Under these conditions, thelevel of acceptance of teachers increased. The aspect ratio capability Indonesian teachers inpreparing lesson plans through the provision of duty cycle I and II of the increase from 56%and the second cycle to 79%.

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