http://dspace.dtu.ac.in:8080/jspui/handle/123456789/76 2026-07-02T12:54:05Z 2026-07-02T12:54:05Z SHAHI, CHITRESH SREEJETH, MINI (SUPERVISOR) http://dspace.dtu.ac.in:8080/jspui/handle/repository/22952 2026-06-25T05:09:50Z 2026-05-01T00:00:00Z

Title: DIRECT TORQUE CONTROL OF PMSM USING PI CONTROLLERS AND SVPWM FOR TORQUE RIPPLE REDUCTION Authors: SHAHI, CHITRESH; SREEJETH, MINI (SUPERVISOR) Abstract: This thesis investigates and compares the modelling, control mechanisms, and performance outcomes of FOC and PI-SVPWM-based DTC techniques for a PMSM drive system. The increasing demand for efficient control strategies in high-performance electric drive applications can offer fast dynamic response, better steady-state performance and reduced torque ripple. In this work, the mathematical modelling of PMSM is developed using abc and d-q reference frame transformations. An analysis of traditional DTC is conducted to identify key drawbacks, particularly its variable switching frequency and elevated ripples in both flux and torque. The proposed PI-SVPWM-based DTC method and FOC technique are implemented in MATLAB/Simulink environment under similar operating conditions for fair performance evaluation. The simulation results are analyzed analysis between FOC and proposed DTC technique is also carried out to evaluate their dynamic and steady-state performance.in terms of speed, electromagnetic torque and transient characteristics. The obtained results show that, in comparison to conventional DTC, the suggested PI-SVPWM-based DTC technique offers better steady-state performance. The FOC technique offers smooth current control and stable operation. Therefore, the proposed control strategy can be considered an effective solution for high-performance PMSM drive applications.

2026-05-01T00:00:00Z PURBIA, KUSHAL Ramana, Vanjari Venkata (SUPERVISOR) http://dspace.dtu.ac.in:8080/jspui/handle/repository/22949 2026-06-25T05:09:24Z 2026-06-01T00:00:00Z

Title: DESIGN AND IMPLEMENTATION OF POWER CONVERTERS FOR CHARGING APPLICATIONS WITH IMPROVED PFC Authors: PURBIA, KUSHAL; Ramana, Vanjari Venkata (SUPERVISOR) Abstract: With increasing popularity of electric vehicles and the growing need for fast and efficient charging stations, there exists a necessity for designing a power converter system that will provide a highly regulated DC output voltage at low voltage levels in response to a standard AC supply voltage. In this thesis, a two-stage power converter system consisting of an interleaved boost power factor correction converter, which is followed by a full bridge LLC resonant converter, will be designed and analyzed. The proposed power converter system has been designed for a rated power of 3 kW, which provides a highly regulated output voltage of 48 V. For providing high efficiency and reduced switching losses, the first stage consists of an interleaved boost power factor correction converter, which directly converts the mains AC voltage (230 V) to regulated DC link voltage of 400 V. This stage ensures regulation of the DC link voltage to 400 V and provides a high-power factor due to shaping of input current waveforms to follow the input sinusoidal voltages. Interleaving is done by means of 1800 out-of-phase gating signals applied to two identical boost converters operated in parallel with one another. The second stage consists of a full-bridge LLC resonant converter that accepts the 400 V regulated DC link voltage and delivers a controlled output voltage of 48 V at 3 kW. The operating principles of the LLC converter are examined across three frequency regions: at resonance, below resonance, and above resonance. The first harmonic approximation method is employed to derive the voltage gain expression, which forms the basis of a systematic resonant tank design procedure covering the selection of Qmax, optimization of the inductance ratio m, and explicit calculation of the resonant component values Lr, Cr, and Lm. A closed-loop voltage controller based on pulse frequency modulation is designed to regulate the 48 V output under both load-side and input-side disturbance conditions. The complete system is modelled and validated through simulation studies in MATLAB Simulink. Results confirm stable output voltage regulation at 48 V, high power factor at the AC input, satisfactory dynamic response under load and input voltage variations, and maintained soft-switching operation across the intended operating range of the full-bridge LLC resonant converter.

2026-06-01T00:00:00Z PRANEETH, KURMANA Valluru, Sudarshan K. (SUPERVISOR) http://dspace.dtu.ac.in:8080/jspui/handle/repository/22948 2026-06-25T05:09:16Z 2026-05-01T00:00:00Z

Title: DESIGN AND ANALYSIS OF A CASCADED HIGH-GAIN BOOST-BUCK CONVERTER FOR BATTERY CHARGING APPLICATIONS Authors: PRANEETH, KURMANA; Valluru, Sudarshan K. (SUPERVISOR) Abstract: This project presents detailed analysis on the design, analysis and regulation of two stage dc-dc conversion system intended for application in energy harvesting and high power battery charging system. The developed system utilizes High-Gain Boost converter and subsequently the Buck converter that efficiently converts the low voltage dc power generated from sources like PV or fuel cells and produces regulated dc outputs that can be utilized for charging applications. The primary objective of the proposed work is to achieve high voltage gain, maintain a constant and stable DC-Link voltage, and utilize this DC-Link output as the input to a cascaded buck converter for efficient battery charging applications. The thesis commences with the execution of a non isolated, non-coupled inductor-based high-gain DC-DC boost converter topology intended to increase variable low-input DC voltage to a stable 300 V DC-link. The novel boost converter employs two switches controlled by a single Pulse Width Modulator (PWM), this configuration makes the converter a compact economical and lightweight design with an uncomplicated control architecture. The converter is engineered to deliver a significant voltage gain at reduced duty cycles while ensuring minimal voltage stress across each switch during switching. Its operation facilitates significant voltage amplification, making it highly suitable for the use in renewable energy systems where efficient low-to-high voltage conversion is required. The novel boost converter exhibits an enhanced gain characteristics and also improved efficiency compared to the conventional boost converter, thus improving overall system reliability and performance. Following the boost conversion process, the regulated 300V DC-link works as the input to the Buck converter which will buck the DC-link voltage to a regulated 48V level suitable for the 1kW battery charger output ensuring accuracy of voltage and current at the output. The objective of this step is to provide safe and consistent charging operation for varied loads and varying sources. The boost buck topology provides the most effective conversion and regulation process for modern day charging facilities, DC microgrids and renewable energy storage systems. Controller designs for both converters have been developed by employing PI controller based feedback approach to stabilize the DC-Link voltage in case of Boost converter and to provide a regulated output voltage and current in case of the Buck converter. The control design provides a very good dynamic performance, high efficiency operation, high voltage gain, minimum switch stresses and resilience under input and load variation. By cascading these two stages the system would attain high power conversion and energy transfer capabilities. The current research work focuses on developing technically advanced converter topology by combining a high voltage gain process and a high efficiency conversion technique for renewable energy applications,with the efficacy of the given converter system validated through comprehensive MATLAB/Simulink simulation study.

2026-05-01T00:00:00Z SINGH, GOVIND Meena, Ram ji Lal (SUPERVISOR) Kaushik, Gaurav (CO-SUPERVISOR) http://dspace.dtu.ac.in:8080/jspui/handle/repository/22946 2026-06-25T05:08:59Z 2026-05-01T00:00:00Z

Title: CONTROLLER DESIGN FOR A BOOST CONVERTER USING CONSTRAINED STABILITY BOUNDARY LOCUS Authors: SINGH, GOVIND; Meena, Ram ji Lal (SUPERVISOR); Kaushik, Gaurav (CO-SUPERVISOR) Abstract: Due to rising demands for clean energy, transition from conventional sources to renewable sources of energy is also rising. The integration of the renewable energy sources to high voltage dc bus has necessitated the use of DC DC boost converters. The intermittency of these sources can be countered effectively by the closed-loop operation of the converters. The design of the controller is critical as it provides converter with good dynamic response, and effective voltage regulation against source and load disturbances. This article aims to provide a simple, analytical, and graphical way to tune the PI/PID type controllers. The controller parameterization is done on the basis of obtained stability boundary locus which is further constrained by the boundaries obtained for gain margin, and phase margin providing the controller sufficient robustness to uncertainties. The analytical study is supported with the MATLAB simulations. A 24/110 V, 100 W boost converter has been designed and simulation results are also provided.

2026-05-01T00:00:00Z