Analysis, Design and Experimental Validation of Modified Simple Soft Switching DC-DC Boost Converter

This paper investigates a modified simple soft switching dc-dc converter for low power applications. This simple topology uses an auxiliary switch, an inductor and a capacitor to operate the converter without switching losses. The efficiency of the converter is improved by transferring the energy that would be dissipated during the switching to the load. The main switch turns-on with zero current switching (ZCS) and turns-off with zero voltage switching (ZVS), while the auxiliary switch turns-on and turns-off with zero voltage switching (ZVS). The detailed theoretical analysis and the design equations are described. In addition to that, the analysis of proposed converter is demonstrated by both simulation and experimental results for effectiveness of the study.Web of Science16433733

Robust detection of real-time power quality disturbances under noisy condition using FTDD features

To improve power quality (PQ), detecting the particular type of disturbance is the foremost thing before mitigation. So monitoring is needed to detect the PQ disturbance that occurs in a short duration of time. Classification of real-time PQ disturbances under noisy environment is investigated in this method by selecting an appropriate signal processing tool called fusion of time domain descriptors (FTDD) at the feature extraction stage. It’s a method of extracting power spectrum characteristics of various PQ disturbances. Few advantages like algorithmic simplicity and local time-based unique features makes the FTDD algorithm ahead of other techniques. PQ events like voltage sag, voltage swell, interruption, healthy, transient and harmonics mixed with different noise conditions are analysed. multiclass support vector machine and Naïves Bayes (NB) classifiers are applied to analyse the performance of the proposed method. As a result, NB classifier performs better in noiseless signal with 99.66%, wherein noise added signals both NB and SVM are showing better accuracy at different signal to noise ratios. Finally, Arduino controller-based hardware tool involved in the acquisition of real-time signals shows how our proposed system is applicable for industries that make detection simple

Investigation of a bidirectional DC/DC converter with zero-voltage switching operation for battery interfaces

This paper proposes a bidirectional DC-DC converter with soft-switching capabilities. The main characteristic of this converter is that it can be operated in both boost and buck modes. The major advantages of this converter are high efficiency and reduced switching loss in high-power and high-voltage applications. The soft-switching capability is obtained by additional dual auxiliary resonant circuits connected to the conventional non-isolated bidirectional DC-DC converter. Except for the auxiliary switches, all main switches turn on with zero-voltage switching in this proposed bidirectional DC-DC converter. The auxiliary switches turn off with zero current transition. The principle of operation, theoretical analysis and experimental results of a 175 V/385 V bidirectional DC-DC converter at 2 KW output power with switching frequency of 50 kHz are provided. The experimental results verified the zero-voltage switching operation for boost and buck modes with efficiencies 96.5% and 96%, respectively, at full load.This research has been supported by the Ministry of Education, Youth and Sports of the Czech Republic under the project OP VVV Electrical Engineering Technologies with High-Level of Embedded Intelligence CZ.02.1.01/0.0/0.0/18_069/0009855 and project No. SGS-2018-009.Scopu

A semi-synthetic chickpea flour based diet for long-term maintenance of laboratory culture of helicoverpa armigera

Artificial rearing of insects in the laboratory is a pre-requisite for undertaking studies on insecticide/ biopesticide bioassays, and evaluation of germplasm, segregating breeding material, mapping populations, and transgenic plants for resistance to insects. For successful rearing of insects in the laboratory, there is need for standardizing a semi-synthetic diet that supports survival and development of the insect for several generations. We tested different semi-‘synthetic diets for rearing the legume pod borer, Helicoverpa armigera for two generations under laboratory conditions. All the semi-synthetic diets tested supported the growth and development of H. armigera up to adult emergence, but there were significant differences in survival and development and fecundity on different diets. The highest larval survival was observed in the wheatgerm based diet in first (97.5%) and second generation (93.5%), followed by chickpea based modified diet (93.75% survival in both the generations). The lowest larval weights (270.7 and 283.7 mg) were recorded in the tapioca granules diet in 1st and 2nd generation, respectively. The adult emergence ranged from 68.7 to 83.3%, and 60.4 to 81.2% in the 1st and 2nd generation, respectively. Least fecundity was observed in the tapioca granules based diet (422 and 603 eggs per female) in both the generations, but the differences were not significant. Complete or partial replacement of agar-agar with tapioca granules was not suitable for use in artificial diets. The results indicated that modified chickpea flour based diet was quite appropriate for rearing H. armigera under laboratory condition

Grid Synchronization Algorithm For DG Systems Using DSRF PLL

Distributed Generation (DG) System is a small scale electric power generation at or near the user’s facility as opposed to the normal mode of centralized power generation. In order to ensure safe and reliable operation of power system based on DS, grid synchronization algorithm plays a very important role. This paper presents a novel Double Synchronous Reference Frame (DSRF) PLL (based on synthesis circuit) for grid connected inverter system under grid disturbances. Due to flexible in characteristics, DSRF PLL can accurately detect the phase irrespective of the grid conditions. Further, it demonstrates how the PLLs track the phase angle during some of the major abnormal grid conditions like voltage unbalance, line to ground fault and voltage sag etc

Study of inverter-interfaced wind power generation system under balanced & unbalanced grid voltage conditions

This thesis presents the control of grid-side converter (GSC) for wind turbine based power generation system under balanced and unbalanced grid voltage conditions. For that Doubly-Fed Induction Generator (DFIG) with two back-to-back bi-directional voltage source converters are considered and are examined in the laboratory experimental set-up through DSP TMS320F2812 digital processor platform. The major role of GSC is to interact with the utility grid. Moreover, the control of GSC is necessary to meet the following bjectives 1): control of active power delivered to the grid, control of reactive power exchanged between the DFIG and the utility grid, control of the DC-link voltage, power quality improvement and grid synchronization etc. Grid-Side converter (GSC) control is an obvious choice to optimize the power quality problems, harmonic compensation and full reactive power support to the grid by reactive current injection during grid abnormalities. Under balanced condition, voltage oriented control (VOC) algorithm is studied in the grid-side converter (GSC) in order to control the active and reactive power of the grid independently through control of id and iq components of the grid currents. However, the converter performance largely depends on the applied current control strategy in the inner control loop. In this study, there are three current controllers are projected namely; SVPWM with Proportional Integral (PI) current controller, hysteresis current controller (HCC), and adaptive hysteresis current controller (AHCC) and their performance is analyzed during steady state and transient conditions. SVPWM with portional Integral (PI) current controller is implemented in the synchronous rotating reference frame (dq reference frame) control algorithm. HCC and AHCC are implemented in the natural reference frame (abc reference frame) control algorithm. Further, a comparative study is made between the three current controllers, in order to ensure the sinusoidal current injected into the grid. The performance indices include THD of the grid current, DC-link utilization, dynamic response etc. In addition to that, control of grid-side converter control is also studied during unbalanced grid voltage conditions. During unbalanced condition of the grid voltages, operation of grid side converter is decisive due to failure of detecting exact grid flux position for voltage oriented control (VOC) algorithm; unless an independent control for the positive and the negative sequence is implemented. In this study, detection of positive fundamental component and negativesequence component are achieved by phase locked loop (PLL) using double rotating reference frames to transform the input signal. The control strategy applied to grid-side converter is implemented in stationary (αβ) reference frame using fast acting proportional-resonant (PR) current controller. The effectiveness of the techniques studied in this dissertation is demonstrated by both simulation and experimental results based on TMS320F2812 digital signal processor platform

An algorithm for the improvement of linear separation

A method is presented for the improvement of linear separation. The characteristic vector is modified using the required distance of the boundary from the nearest pattern. Using this modified characteristic vector the weight vector is adjusted

An iterative procedure for the training of a two-layered machine

An iterative method is presented for the training of a two-layered machine used for pattern dichotomization. It is assumed that there is only one TLU in the second layer and a number of TLU's in the first layer. The central idea of the method is getting the desired responses of the first-layer TLU's, knowing the desired response of the output TLU. Using these desired responses the TLU's are adjusted. A method is given for testing the non-linear separability of R category case