BITS Faculty Publications
Permanent URI for this communityhttp://localhost:4000/handle/123456789/1867
Browse
40 results
Search Results
Item A large step down buck converter for small scale hydrogen generation(IEEE, 2025-12) Pande, Surojit; Kumar, RajneeshThis paper presents a large step-down buck converter topology employing a coupled inductor and a singles-witch configuration to achieve efficient step-down voltage conversion with an extended conversion ratio. The proposed architecture mitigates the limitations of conventional buck converters by leveraging a coupled inductor to enhance voltage gain while maintaining a moderate duty cycle, thereby reducing conduction and switching losses. The developed single-switch topology is validated using MATLAB Simulation and comprehensive theoretical analysis is conducted, including steady-state operation, voltage gain expression, and component stress evaluation representing hydrogen electrolyser as resistive load in steady stateItem Fabrication of stable ru-doped ni0.95se nanostructures for photovoltaic coupled electrochemical water splitting in alkaline medium(Wiley, 2025-01) Pande, Surojit; Kumar, RajneeshDevelopment 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.Item ZCS-ZVS Operation of a Double Frequency High-Voltage Gain Boost Converter(IEEE, 2023-02) Kumar, RajneeshFor renewable energy systems, power electronics are significant because they reduce fuel costs, increase efficiency, and increase reliability. Recently, some converter topologies are achieving up to 400V for grid application from solar PV modules using two-stage boost converters. So, a quadratic boost converter is designed with a double frequency approach to achieve an output voltage of more than 400V. The proposed converter’s steady-state analysis in CCM and DCM is examined with 93%efficiency to figure out how to express overall gain in terms of duty ratios and MOSFET operational switching frequencies.Item An Approach to eliminate the Non-Minimum Phase issue in High Gain Converters(IEEE, 2022) Kumar, RajneeshHigh-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.Item An active clamp coupled inductor-based soft-switched quadratic boost converter(Wiley, 2022-12) Kumar, RajneeshThis 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.Item Implementation of Pulse-Width-Modulation based Sliding Mode Controller for Semi-Quadratic Buck-Boost DC/DC Converter(IEEE, 2023) Kumar, RajneeshThis research discusses the robust performance of a semi-quadratic buck-boost converter with a sliding mode (SM) controller. It is a non-linear control strategy having a lot of advantages of easy implementation and giving better dynamic response against load perturbation. A detailed examination of the stability of the control system in the closed-loop configuration is carried out, along with the derivation of an equivalent control signal for the recommended sliding mode controller. This approach utilizes the input-output linearization technique and the equivalent control method to define the boundary layers encompassing the sliding surface. A comparison of this proposed controller with a conventional PID controller is also done. The MATLAB simulation outcomes are showcased to demonstrate and exemplify the proposed methodology.Item Implementation of Lyapunov Function-Based Hybrid Controller in Semi-Quadratic Buck-Boost Converter(IEEE, 2023-11) Kumar, RajneeshThis article presents a novel Semi-Quadratic buckboost converter (SQBuBoC) designed to integrate in many applications with a wide range of output voltage such as photovoltaic systems. The efficient control and energy management of renewable-driven stand-alone systems has been areas of active research. However, effectively managing both the renewable energy source and the distributed energy stored while meeting the load requirements remains a challenge. This study focuses on evaluating the performance of a SQBuBoC with a Lyapunov function-based controller. The proposed controller employs a combination of a duty-ratio feedforward control unit and a Lyapunov function-based control unit. The duty-ratio feedforward control unit is responsible for reducing the workload on the feedback controller. By utilizing this control scheme, the closedloop system achieves exponential stability and exhibits excellent transient responsiveness, even when subjected to significant disturbance. The MATLAB simulation outcomes are showcased to demonstrate and exemplify the proposed methodology.Item Designing a Fuzzy Logic Controller for Soft-Switched Quadratic Boost Converter(IEEE, 2023) Kumar, RajneeshThis 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.Item A new soft-switching high step-up DC–DC converter with low voltage stress(Wiley, 2024-06) Kumar, RajneeshThis paper proposes a new high step-up DC–DC converter with zero input current ripple for renewable energy sources applications, such as fuel cells. In this topology, a coupled inductor and a multiplier cell are used to achieve high voltage gains. The power switch in this proposed circuit turns on under zero voltage switching conditions. An active switch limits the maximum voltage stress across the main power switch. Moreover, all circuit diodes of the converter turn off without a reverse recovery problem. A detailed analysis of a high-gain step-up DC–DC converter is studied along with improved efficiency. The ripple cancellation of the input stage of the converter is done by adding an input inductor and capacitor. By including the parasitic elements, an approximate loss analysis was performed in PSIM and found the maximum efficiency of ∼96% in simulation and ∼94% in hardware for 200 W power level design for 30 V input voltage. Later on, the converter laboratory hardware prototype can be developed with selected parameters, and finally, experimental results have been used to validate the properties of the converterItem Enhanced Performance of Cuk and Boost–Based High-Gain Step-Up DC/DC Converter(Wiley, 2024-11) Kumar, RajneeshThis 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.