938 resultados para Power supply quality


Relevância:

100.00% 100.00%

Publicador:

Resumo:

The harmonic oscillations of a Duffing oscillator driven by a limited power supply are investigated as a function of the alternative strength of the rotor. The semi-trivial and non-trivial solutions are derived. We examine the stability of these solutions and then explore the complex behaviors associated with the bifurcations sequences. Interestingly, a 3D diagram provides a global view of the effects of alternate strength on the appearance of chaos and hyperchaos on the system.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The main objective of this work is the design and implementation of the digital control stage of a 280W AC/DC industrial power supply in a single low-cost microcontroller to replace the analog control stage. The switch-mode power supply (SMPS) consists of a PFC boost converter with fixed frequency operation and a variable frequency LLC series resonant DC/DC converter. Input voltage range is 85VRMS-550VRMS and the output voltage range is 24V-28V. A digital controller is especially suitable for this kind of SMPS to implement its multiple functionalities and to keep the efficiency and the performance high over the wide range of input voltages. Additional advantages of the digital control are reliability and size. The optimized design and implementation of the digital control stage it is presented. Experimental results show the stable operation of the controlled system and an estimation of the cost reduction achieved with the digital control stage.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This paper presents an envelope amplifier solution for envelope elimination and restoration (EER), that consists of a series combination of a switch-mode power supply (SMPS), based on three-level voltage cells and a linear regulator. This cell topology offers several advantages over a previously presented envelope amplifier based on a different multilevel topology (two-level voltage cells). The topology of the multilevel converter affects to the whole design of the envelope amplifier and a comparison between both design alternatives regarding the size, complexity and the efficiency of the solution is done. Both envelope amplifier solutions have a bandwidth of 2 MHz with an instantaneous maximum power of 50 W. It is also analyzed the linearity of the three-level cell solution, with critical importance in the EER technique implementation. Additionally, considerations to optimize the design of the envelope amplifier and experimental comparison between both cell topologies are included.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In this paper, implementation and testing of non- commercial GaN HEMT in a simple buck converter for envelope amplifier in ET and EER transmission techn iques has been done. Comparing to the prototypes with commercially available EPC1014 and 1015 GaN HEMTs, experimentally demonstrated power supply provided better thermal management and increased the switching frequency up to 25MHz. 64QAM signal with 1MHz of large signal bandw idth and 10.5dB of Peak to Average Power Ratio was gener ated, using the switching frequency of 20MHz. The obtaine defficiency was 38% including the driving circuit an d the total losses breakdown showed that switching power losses in the HEMT are the dominant ones. In addition to this, some basic physical modeling has been done, in order to provide an insight on the correlation between the electrical characteristics of the GaN HEMT and physical design parameters. This is the first step in the optimization of the HEMT design for this particular application.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Power supply unpredictable uctuations jeopardize the functioning of several types of current electronic systems. This work presents a power supply sensor based on a voltage divider followed by buffer-comparator cells employing just MOSFET transistors and provides a digital output. The divider outputs are designed to change more slowly than the thresholds of the comparators, in this way the sensor is able to detect voltage droops. The sensor is implemented in a 65nm technology node occupying an area of 2700?m2 and displaying a power consumption of 50?W. It is designed to work with no voltage reference and with no clock and aiming to obtain a fast response.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The location of ground faults in railway electric lines in 2 × 5 kV railway power supply systems is a difficult task. In both 1 × 25 kV and transmission power systems it is common practice to use distance protection relays to clear ground faults and localize their positions. However, in the particular case of this 2 × 25 kV system, due to the widespread use of autotransformers, the relation between the distance and the impedance seen by the distance protection relays is not linear and therefore the location is not accurate enough. This paper presents a simple and economical method to identify the subsection between autotransformers and the conductor (catenary or feeder) where the ground fault is happening. This method is based on the comparison of the angle between the current and the voltage of the positive terminal in each autotransformer. Consequently, after the identification of the subsection and the conductor with the ground defect, only the subsection where the ground fault is present will be quickly removed from service, with the minimum effect on rail traffic. This method has been validated through computer simulations and laboratory tests with positive results.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Supported by: Office of Naval Research under contract N000 14-67-A-0305-0007.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Cover title.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

"16 September 1964."