Search results for "Converter"
showing 10 items of 275 documents
Fault Tolerant Ancillary Function of Power Converters in Distributed Generation Power System within a Microgrid Structure
2013
Distributed generation (DG) is deeply changing the existing distribution networks which become very sophisticated and complex incorporating both active and passive equipment. The simplification of their management can be obtained assuming a structure with small networks, namely, microgrids, reproducing, in a smaller scale, the structure of large networks including production, transmission, and distribution of the electrical energy. Power converters in distributed generation systems carry on some different ancillary functions as, for example, grid synchronization, islanding detection, fault ride through, and so on. In view of an optimal utilization of the generated electrical power, fault to…
H∞ fuzzy control of DC-DC converters with input constraint
2012
Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http://dx.doi.org/10.1155/2012/973082 Open access This paper proposes a method for designing H∞ fuzzy control of DC-DC converters under actuator saturation. Because linear control design methods do not take into account the nonlinearity of the system, a T-S fuzzy model and a controller design approach is used. The designed control not only handles the external disturbance but also the saturation of duty cycle. The input constraint is first transformed into a symmetric saturation which is represented by a polytopic model. Stabilization conditions for the H∞ state feedba…
Control and power management of Photovoltaic-battery based micro grid
2016
The growing demand for electrical power and the interruption of the power supply has paved the way for the realization of renewable based energy generation. This paper presents the control and power management of a hybrid microgrid system that comprises Photovoltaic (PV) array, battery, and local AC load, connected to the utility grid. This work focuses on the compensation of PV power reduction due to partial shading using bidirectional half bridge converter with battery storage. This system considers fulfilling the local load demand through PV production and, then, to manage the power among the battery and grid. In the proposed system, the considered power conditioning devices area boost c…
A standard-compliant prototype for PV module curve detection
2014
In this paper, a prototype for PV module curve detection which features low cost and size and ensures high accuracy is proposed. The proposed architecture is based on a buck-boost converter in open-loop configuration. The proposed architecture is fully compliant with actual standard IEC60904. The duty-cycle control algorithm and its own effects on system performances are accurately investigated. The comparison of different duty-cycle patterns is carried out and performance evaluation is performed. Simulation results are shown to perform a valuable comparison of control algorithms. Preliminary experimental results on a laboratory prototype are presented.
Current-Sensing Technique for Current-Mode Controlled Voltage Regulator Modules
2008
This paper introduces an innovative current-sense technique for voltage regulator modules (VRMs). The proposed method is applied to a multiphase buck converter although the converter topology does not affect the accuracy or effectiveness of the proposed technique. A RC network is parallel connected with the buck converter low-side MOSFET and the voltage signal across the sense capacitor reconstructs the inductor current waveform. The RC technique benefits from all the advantages of the most popular current-sensing technique, the inductor DC resistance current-sense method, cutting off its main disadvantage. The sense network design is oriented to obtain high immunity to noise and a great dy…
Design And Characterization Of Automated Color Sensor System
2017
Abstract The paper presents a color sensor system that can process light reflected from a surface and produce a digital output representing the color of the surface. The end-user interface circuit requires only a 3-bit pseudo flash analog-to-digital converter (ADC) in place of the conventional/typical design comprising ADC, digital signal processor and memory. For scalability and compactness, the ADC was designed such that only two comparators were required regardless of the number of color/wavelength to be identified. The complete system design has been implemented in hardware (bread board) and fully characterized. The ADC achieved less than 0.1 LSB for both INL and DNL. The experimental r…
Can the effective number of bits be useful to assess the measurement uncertainty?
2003
The effective number of bits (ENOB) is a well know parameter, employed to characterize the overall behavior of an A/D converter. In order to verify if the ENOB can be also used to assess the measurement uncertainty of the A/D conversion based instruments, we use a developed software tool. The results show that using the ENOB can lead to an underestimate of the uncertainties.
Quasi-digital conversion for resistive devices: application in GMR-based IC current sensors
2013
Resistive devices, including sensors, are used in a huge range of applications within different scenarios. When a complete system is considered, a quasi-digital output is often recommendable. If the conversion is operated at device level, some problems such as noise disturbs, insertion losses and so on, can be reduced. In this work, we describe a resistance-tofrequency (R-f) converter with a suggested application in low current monitoring by means of GiantMagnetoResistance (GMR) sensors. Specific devices have been designed and microfabricated. The system has been tested by means of discrete components with a PCB. The complete microsystem monolithic integration in a standard CMOS technology …
Sensorless low Range Speed Estimation and Parameter Identification of Induction Motor Drives Devoted to Lifts Automatic Rescue Devices
2010
In this paper a sensorless rotor speed estimation and parameter identification algorithm is presented. The algorithm is designed specifically for induction motor (IM) drives devoted to automatic rescue devices (ARD) used in lifts and hoist applications. Its peculiarity is that it is based on the sinusoidal steady state mathematical model of the IM and, therefore, can be implemented on a low cost micro-controller in a simple way, however without lacking in terms of dynamic performance. It is also capable of self tuning so that no information is required about the specific IM used in the ARD drive. Finally the algorithm allows also an appreciable energy saving of the ARD when compared to olde…
Active load sharing technique for on-line efficiency optimization in DC microgrids
2017
Recently, DC power distribution is gaining more and more importance over its AC counterpart achieving increased efficiency, greater flexibility, reduced volumes and capital cost. In this paper, a 24-120-325V two-level DC distribution system for home appliances, each including three parallel DC-DC converters, is modeled. An active load sharing technique is proposed for the on-line optimization of the global efficiency of the DC distribution network. The algorithm aims at the instantaneous efficiency optimization of the whole DC network, based on the on-line load current sampling. A Look Up Table, is created to store the real efficiencies of the converters taking into account components toler…