The growth of renewable energy in the last two decades has led to the development of new power electronic converters. The DC microgrid can operate in standalone mode, or it can be grid-connected. A DC microgrid consists of various distributed generation (DG) units like solar PV arrays, fuel cells, ultracapacitors, and microturbines. The DC-DC converter plays an important role in boosting the output voltage in DC microgrids. DC-DC converters are needed to boost the output voltage so that a common voltage from different sources is available at the DC link. A conventional boost converter (CBC) suffers from the problem of limited voltage gain, and the stress across the switch is usually equal to the output voltage. The output from DG sources is low and requires high-gain boost converters to enhance the output voltage. In this paper, a new high-gain DC-DC converter with quadratic voltage gain and reduced voltage stress across switching devices was proposed. The proposed converter was an improvement over the CBC and quadratic boost converter (QBC). The converter utilized only two switched inductors, two capacitors, and two switches to achieve the gain. The converter was compared with other recently developed topologies in terms of stress, the number of passive components, and voltage stress across switching devices. The loss analysis also was done using the Piecewise Linear Electrical Circuit Simulation (PLCES). The experimental and theoretical analyses closely agreed with each other.
Stand-alone photovoltaic (SAPV) systems are being used in remote areas and are being seen as one of the promising solution in this regard. The SAPV system as presented in the paper consists of solar PV panel, a DC-DC converter, a controller and a PMDC motor. The current-voltage and power-voltage characteristics being nonlinear, the SAPV system require maximum power point techniques (MPPT) control techniques to extract maximum power available from the PV cell. A voltage based MPPT technique which is capable of tracking MPP has been selected because of numerous advantages it offers such as: simple and low cost of implementation. The limitation of constant voltage method is that its efficiency is low as the PV panel has to be disconnected from the load for measurement of the open circuit voltage (V<sub>oc</sub>). In the presented paper, the authors have removed this limitation by using a pilot PV panel for measurement of V<sub>oc</sub>. A proportional-integrator (PI) based controller is used in implementation of constant voltage MPP technique and the modeling is done in MATLAB<sup>®</sup>/SIMULINK simulation environment. The simulation results are presented and discussed in the paper, the results shows that the efficiency of the system has increased.
Abstract. Practically speaking, not all real estate construction projects are accomplished in the defined span and within budget. Various factors responsible for occurrence of delays are one of the long-standing issues in the field of real estate. Delays make contractors endure productivity loss, cause high disturbance expenses, and prolongation costs. The aim of the research is to summarize several delay causing factors, which are observed in the execution of previous real estate construction projects. It then proposes implementation of standard prevention procedures to minimize delays. Time effect examination is the approach to evaluating and allotting the upshots of delays or changing a venture schedule. This review sets execution framework of the two sub-principles of the Toyota Way attributes known as philosophy sub-principles and process subprinciples to guide real estate construction businesses in their lean change to delay free real estate construction work. These are implemented after investigating the critical factors responsible for delays in the delayed projects by comparing their as-planned schedules with the adjusted schedules. Methods used in the research include structured surveys and content analysis, which is performed after collection of quantitative data from the respondents. The lean construction principles will be designed and provided to clients to be productive in performing work packages on their scheduled time with minimum possibility of time overrun.
<p><span lang="EN-US">This work proposes an adaptive filter based on a new least mean sixth control approach with incremental conductance method of MPP for 3-phase grid-incorporated photovoltaic (PV) system. The proposed system comprises a PV array, 3-phase DC to AC converter, maximum power point tracker (MPPT), three-phase electronic load, and a 3-phase grid. The combination of solar PV array and the voltage source converter (VSC) supplies power to the grid. The 3-phase inverter as a distribution static synchronous compensator (D-STATCOM) improves the quality of the system performance in case of zero solar irradiation. D-STATCOM also reduces total harmonic distortion (THD) in grid currents, improves power factor, and maintainsa constant voltage at the point of common coupling (PCC). The system modelling and simulation is achieved on MATLAB/Simulink. The proposed system performance has been found satisfactory and conform to IEEE-519 standards.</span></p>
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