Browsing by Author "Kumar, Rajneesh"

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An active clamp coupled inductor-based soft-switched quadratic boost converter
(Wiley, 2022-12) Kumar, Rajneesh
This paper proposes a novel active clamp-based quadratic boost converter to achieve a high gain output voltage. The converter combines a quadratic boost converter with a voltage doubler circuit using a coupled inductor. An active clamp circuit with an auxiliary switch is used to utilize the usually wasted energy of leakage inductance and clamp the voltage to a certain limit. The combination of leakage inductance and parasitic capacitance of the main switch provides the benefit of zero voltage switching (ZVS) in both MOSFETs. Similarly, output diodes operating under zero current switching (ZCS) improve the overall efficiency of the converter. Voltage doubler and active clamp circuitry reduce the voltage stress on solid-state devices; hence, a low Rds,on device is selected. The converter model is simulated using PSIM software and calculated maximum efficiency of ~95% for 200 W and measured maximum efficiency of ~93% for 190 W power level including various parasitic elements.
Active Power Filter Control Algorithm using Wavelets
(IEEE, 2006) Kumar, Rajneesh; Gupta, Karunesh Kumar
This paper presents a wavelet transform (WT) based technique to extract fundamental frequency component from a nonsinusoidal and unbalanced load current in a three phase system. The fundamental frequency component is extracted using multiresolution analysis (MRA). The remaining harmonics can be used by the active filter for compensation. Simulation result obtained for a rectifier load current shows the usefulness of the proposed method.
Advancing renewable energy: A quadratic high-efficiency high gain step-up DC/DC converter
(Elsevier, 2024-12) Kumar, Rajneesh
Presenting a new high-gain converter that incorporates a coupled inductor, this paper offers a range of advantages over existing designs. The circuit features a simple structure with two cascade semi-stages, two power switches operating in sync, and a coupled inductor. It provides an extensive output voltage range, ensures continuous input current with minimal ripple, maintains positive output voltage polarity, and follows a standard ground configuration. These features make it well-suited for various applications, particularly in photovoltaic systems. Additionally, the voltage stress across each power switch is significantly lower than that of other boost converters, allowing for the selection of power MOSFETs with reduced drain-source ON resistance to ensure high efficiency. This research presents comprehensive assessments of the steady-state and stress conditions as well as thorough comparisons with other similar converters operating in continuous conduction mode. Theoretical advantages of the proposed circuit design are further reinforced by experimental results obtained from a 200-W step-up 25–370 V arrangement.
Analysis of irradiance losses on a soiled photovoltaic panel using contours
(Elsevier, 2016-05) Kumar, Rajneesh
This paper introduces an irradiance loss factor that quantifies the relationship between irradiance, tilt angle and power output of a soiled panel with the soil particle size composition. Artificial soiling experiments were performed using four soil samples at irradiance levels between 200 and 1200 W/m2 at 18 tilt angles. Biharmonic interpolation was used to develop power contours in terms of irradiance and tilt angle from experimentally obtained data. These contours were compared with ideal ones of a clean panel to observe deviation in the nature of contours for a soiled panel. A correction factor in terms of particle size composition (as a coefficient to tilt angle) was proposed to calculate power output of a tilted soiled panel. The angular loss on a panel with soil sample containing 150 μm particle size in abundance was observed to be 22% and for sample containing 75 μm particles in majority, the loss is 24%. Presence of 300 μm particle size in abundance causes a 23.7% loss, while 52% angular loss was observed for soil with highest composition of less than 75 μm particle size.
Analysis of soil distortion factor for photovoltaic modules using particle size composition
(Elsevier, 2018-02) Kumar, Rajneesh
This paper introduces a soil distortion factor (SDF) to establish a relationship between particle size compositions of soil and irradiance received by a tilted soiled solar panel. Particle size composition of five soil samples was determined using sieve analysis and artificial soiling experiments were performed to measure open circuit voltage (Voc) and short circuit current (Ish) to calculate power output of soiled panel. The power obtained from experimental data was compared with the ideal power output of a clean panel to quantify SDF at three regions of tilt angle. Further, SDF is expressed in terms of particle size composition of soil using regression analysis to calculate irradiance loss. It was observed that the irradiance loss varies with tilt angle and particle composition of soil. Soils rich in particles with 150 µm diameter (Soil 1) and 300 µm diameter (Soil 3) cause irradiance losses up to 6% and 21% while Soil 2 with high composition of 75 µm particle size leads to maximum losses of 10%. Soil 4 with 300 µm particles as its major composition causes losses as high as 22% in the same tilt angle range. Soil 5 having the highest composition of less than 75 µm size particles causes 12% irradiance loss in 0–60° tilt angle region.
An Approach to eliminate the Non-Minimum Phase issue in High Gain Converters
(IEEE, 2022) Kumar, Rajneesh
High-gain converters are widely used in various voltage-boosting applications. There are various types of converters according to their operating principle. Each converter has some advantages and disadvantages according to their application approach. In a non-minimum phase converter, at least one zero occurs in the right half-plane. To eliminate this problem, this paper discussed various converter topologies. The permutation and the combination of the various control techniques, switching elements, magnetic coupling, etc. in the circuit allow for various new topologies and configurations. Additionally, a detailed discussion of the new approaches' benefits and drawbacks is provided. Finally, a broad range of non-minimum dc-dc converter applications is shown and summarized, along with a comparison of several voltage-boosting strategies with stability and efficiency.
Characterization of power losses of a soiled PV panel in Shekhawati region of India
(Elsevier, 2016-06) Kumar, Rajneesh
This paper introduces a model that quantifies the relationship between power output, incident irradiance and soil particle size composition of soiled photovoltaic panels. Soil samples used in artificial soiling experiments were collected from Shekhawati region in India and their relative percentage of standard particle sizes is determined from sieve analysis. A non-linear relationship between irradiance and power is obtained using regression analysis showing the effect of particle size composition present on the panel. Further, the tilt angle for maximum power extraction is determined for each soiled panel and the deviation from the optimum tilt angle of a clean panel is observed. It is concluded that, when the soil present on the panel is rich in the particles with diameter (75 μm and below), the deviation from the tilt angle of a clean panel is 4°, however if the soil contains higher composition of both 150 μm and 300 μm particle sizes the deviation is 8°.
Comparison of SOM and conventional neural network data division for PV reliability power prediction
(IEEE, 2017) Kumar, Rajneesh
This paper studies the influence of neural network clustering in power prediction of soiled PV panels using artificial neural networks. Self-organizing maps were used to cluster and preprocess the data before training the neural network. 70% of data from each cluster is used for training and 15% each for testing and validation. The accuracy of prediction from the developed model was compared with a neural network model which uses random data division without data preprocessing. It was observed that preprocessing the data through clustering would enhance the accuracy of prediction as compared to model developed without data preprocessing. At lower irradiance levels (200-400W/m 2 ) the percentage error in prediction was 8% and at higher irradiance levels (800-1200W/m 2 ) the error decreased to 2%.
Controller Design for High Gain Converters Having Non-Minimum Phase Issues
(IEEE, 2024) Kumar, Rajneesh
This paper discusses the development of a Linear Quadratic Regulator (LQR) control for switching converters with non-minimum phase characteristics. It introduces a feedback loop with a Kalman filter to address observability issues in high-gain converters and simplify control processes. The paper examines design challenges and demonstrates the improved system performance through MATLAB/Simulink simulations.
Coupled-inductor-based high-gain converter utilising magnetising inductance to achieve soft-switching with low voltage stress on devices
(IET, 2020-02) Kumar, Rajneesh
This work proposes a soft-switched quadratic quadrupler boost converter with high voltage step up gain and low voltage stress on devices. With this converter topology, high voltage gain is achieved at low duty ratio operation of MOSFETs and few number of turns in coupled inductor. Operation at low duty ratio keeps boost converter gain in linear region and smaller number of turns in coupled inductor reduces the lossy part of the winding. Further, the magnetising inductance of coupled inductor is utilised to achieve zero voltage switching of MOSFETs to minimise the switching loss. In addition, secondary side diodes are operating under zero current switching conditions using resonance between leakage inductance and the capacitors of voltage quadrupler circuit. This greatly reduces the reverse recovery losses of the secondary side diodes. A detailed analysis of converter dynamics is discussed in one of the subsections to find out small-signal transfer functions with respect to variations in input voltage and duty ratio variation of MOSFETs. A 250 W prototype of the proposed converter is built and tested in laboratory with a maximum efficiency of ∼93% at 175 W output power.
Dependence of hill climbing MPPT algorithm on ADC and Digital filter parameters
(IEEE, 2012) Kumar, Rajneesh
Maximum power point tracking (MPPT) in solar panels has been of prime importance for economic utilization of solar panels. The criterion of noise elimination and sampling rate selection has gained more importance recently because of their significant influence on the tracked power. This paper mainly aims on exploring the effect of ADC and Digital filter parameters on the Incremental conductance MPPT algorithm. The effect of ADC sampling rate and the Digital filter cut offs on the tracking speed and oscillations in tracked voltage and current have been explored. The trend observed in the results has been discussed and the favorable parameter selection criterion has been proposed.
Design and Analysis of Soft-Switching Inverter for UPS Application
(BITS, Pilani, 2008) Kumar, Rajneesh
Design of an Intelligent PD Controller for Artificial Pacemaker
(IEEE, 2012) Bansal, Hari Om; Kumar, Rajneesh
This paper presents the design and analysis of an intelligent control system for regulating the heart rate using a pacemaker. The considered model of the heart is composed of the cardio vascular system duly energised by one pacemaker and operates in closed loop manner. The proposed design emphasises on the optimality in control process. In this work genetic algorithm is used to achieve the optimality. The proposed system is found to be stable with appropriate gain and phase margins. A comparative study of controller tuning using classical approach and the proposed method is made and the best is finally presented. The controllability and observability of the complete system is tested and found to be better for the proposed system
Designing a Fuzzy Logic Controller for Soft-Switched Quadratic Boost Converter
(IEEE, 2023) Kumar, Rajneesh
This paper introduces of successful implementation of fuzzy logic controller (FLC) structure for an active clamp-coupled inductor-based soft-switched Quadratic Boost Converter. This proposed method aims to address several key challenges, including low sensitivity to input voltage variation, fast regulation during load transients, and robustness against aging effects on the converter's passive components. To solve all these issues a fuzzy logic controller (FLC) is designed, it is stated that utilizing a convergent distribution for the membership function leads to a faster response compared to symmetrically distributed membership functions. The robustness of the controller is evaluated under varying loading conditions and input voltage variations. Furthermore, the results are compared with conventional controllers (PI), showing superior dynamic performance. Simulink/ MATLAB is used to validate the performance of the controller.
Dielectric material selection of microstrip patch antenna for wireless communication applications using Ashby's approach
(Cambridge University Press, 2014-07) Gupta, Navneet; Kumar, Rajneesh
In this paper, material selection has been done for dielectric substrate material in microstrip patch antenna (MPA) for three distinct classes of wireless communication applications using Ashby's approach. This material selection procedure is based on the creation and evaluation of Ashby's chart of different material indices. These material indices in turn affect the device performance indices, which decide the best possible dielectric material to be used as substrate for MPAs. In this work, quality factor, relative permittivity, and temperature coefficient of resonant frequency are chosen as material indices of MPA's dielectric substrate to get relevant performances. Ashby's selection chart shows that 0.75MgAl2O4–0.25TiO2 material for millimeter waves applications, Ca[(L1/3Nb2/3)0.85Ti0.15]O3−δ for mobile base station applications, and (Ba0.95Ca0.05)O–Sm2O3–4.5TiO2 ceramic for mobile phone miniaturization applications are the promising materials that allows best overall performance in MPAs for wireless communication.
Enhanced Performance of Cuk and Boost–Based High-Gain Step-Up DC/DC Converter
(Wiley, 2024-11) Kumar, Rajneesh
This article presents a high-gain step-up DC/DC converter based on the Cuk topology for renewable energy applications. The converter employs an auxiliary circuit to achieve less input current ripple, significantly reducing the input inductor size compared to conventional converters. Therefore, the inductor’s equivalent series resistance (ESR) will be substantially lowered to improve power efficiency. Introducing passive clamp capacitors further enhances efficiency by alleviating voltage stress on the main power switch. Comparative studies with other similar converters highlight the unique benefits of converter design. This converter uses a coupled inductor (CI) and a voltage multiplier circuit to achieve high voltage gains. The following article introduces the principle of operation for a proposed topology and analyzes voltage gain, voltage stress, and efficiency. A comprehensive comparison with the most recent counterparts is also included. Finally, a theoretical analysis is verified using a 200-W (30 V/310 V) sample prototype.
Fabrication of stable ru-doped ni0.95se nanostructures for photovoltaic coupled electrochemical water splitting in alkaline medium
(Wiley, 2025-01) Pande, Surojit; Kumar, Rajneesh
Development of a competent and stable electrocatalyst coupled with photovoltaic system for the generation of green hydrogen, can be a plausible answer to the existing energy crisis. Herein, we have developed Ru doped Ni0.95Se via hydrothermal method as a bifunctional catalyst for overall water splitting coupled with photovoltaic system. The developed pristine and doped samples were thoroughly characterized by various techniques. The pristine Ni0.95Se and the optimized Ru0.1Ni0.95Se system required a potential of −0.470 and −0.318 V vs. RHE, respectively to acquire a current density of 50 mA cm−2 for HER. The rapid kinetics of the optimized Ru0.1Ni0.95Se is illustrated by the Tafel slope wherein the pristine Ni0.95Se has a Tafel slope value of 172.2 mV/dec, and the Ru0.1Ni0.95Se catalyst has 102 mV/dec. The bifunctional electrocatalyst of Ru0.1Ni0.95Se exhibits very high stability (7 days) in an alkaline medium. Density functional calculations show Ru0.1Ni0.95Se has −0.69 mathematical equation value indicating its remarkable stability. To improve the overall activity and stability of the electrocatalyst Ru dopant is introduced as it tunes the electronic environment by generating a synergistic effect between the metal ions and Se2− anions. This work provides an approach for the generation of green hydrogen through water electrolysis coupled with PV.
Family of High-Frequency Nonisolated DC-DC ZVZCS Converters with High Conversion Range
(IEEE, 2019) Kumar, Rajneesh
In this paper, two non-isolated DC-DC quadratic boost converters with zero voltage and zero current switching (ZVZCS) are proposed. Voltage boost is achieved by replacing the conventional inductor with coupled inductor having low turns ratio, and using voltage multiplier cell across the secondary side of coupled inductor. Use of clamp circuit with an auxiliary switch provides low voltage stress across solid state devices for entire range of duty ratio operation. Simulation was carried out on PSIM platform to test the validity of design for both converters. Experiments were performed on a designed laboratory prototype for 250 W converter.
Global maximum power point tracking of PV arrays under partial shading conditions using a modified particle velocity-based PSO technique
(IET, 2018-02) Kumar, Rajneesh
Modern PV arrays are generally designed with bypass diodes to avoid damage. However, such arrays exhibit multiple peaks in their P–V characteristics under partial shading conditions. Owing to the limitation in the abilities of conventional maximum power point tracking algorithms in such cases, the application of other optimisation algorithms has been explored. This study proposes a modified particle velocity-based particle swarm optimisation (MPV-PSO) algorithm for tracking the global power peak of the multiple peak P–V characteristics. The MPV-PSO algorithm is both adaptive and deterministic in nature. It eliminates the inherent randomness in the conventional PSO algorithm by excluding the use of random numbers in the velocity equation. The proposed algorithm also eliminates the need for tuning the weight factor, the cognitive and social acceleration coefficients by introducing adaptive values for them which adjust themselves based on the particle position. These adaptive values also solve problems like oscillations about the global best position during steady-state operation and particles getting trapped in local minima. The effectiveness of the proposed MPV-PSO algorithm is validated through MATLAB/Simulink simulations and hardware experiments.
Global maximum power point tracking using variable sampling time and p-v curve region shifting technique along with incremental conductance for partially shaded photovoltaic systems
(Elsevier, 2019-09) Kumar, Rajneesh
This paper proposes modifications to Incremental Conductance (INC) concept to track global maximum power point under partial shading conditions of photovoltaic (PV) systems. The proposed algorithm determines the p-v curve as a combination of regions, and tracks global peak by shifting operating point from one region to another without using any nature inspired intelligent techniques like particle swarm optimization (PSO) and other related algorithms. Additionally, a variable sampling time concept is introduced in the algorithm for faster tracking of global peak under extreme partial shading conditions arising due to random shading pattern of PV modules. MATLAB /SIMULINK platform was used to model PV module in conjunction with SEPIC converter for battery charging application. Proposed algorithm was tested under different shading patterns to observe the tracking speed and accuracy of the tracker. Finally, the concept behind proposed algorithm was validated on TMS320F28027 LAUNCHPAD DSP board using Process-in- loop (PIL) approach for practical applications. Results demonstrate the usefulness of proposed algorithm in terms of less computational time as compared to latest reported work in this field.