MODELLING AND PERFORMANCE ANALYSIS OF A SIDO NEGATIVE OUTPUT SUPER-LIFT LUO CONVERTER INTEGRATED WITH BUCK CONVERTER

Abstract

Auxiliary systems in electric vehicles (EVs) need several regulated voltage levels for the operation of sensors, communication interfaces, embedded controllers, gate driver circuits, cooling systems, and monitoring units. Traditional auxiliary power setups typically utilize several independent DC DC converters to generate different voltage levels, leading to increased circuit complexity, switching losses, thermal stress, component count, and overall converter size. Furthermore, achieving stable regulation with separate converter stages proves challenging under changing operating conditions. This thesis details the modelling, analysis, and closed-loop control of a Single-Input Dual Output (SIDO) integrated DC–DC converter comprising a (NOSL-Luo Converter) combined with a Buck Converter. The topology is designed to simultaneously generate controlled positive and negative output electrical levels from a single 24 V DC input supply. The Buck converter segment delivers a regulated +12 V output ideal for low voltage auxiliary loads, whereas the NOSL-Luo section produces a regulated −48 V output through voltage-lift techniques intended for applications that require high gain negative voltage conversion. The converter is examined under Continuous Conduction Mode (CCM) conditions. Mathematical modeling, operating modes, voltage transfer characteristics, ripple performance, and energy transfer principles of the proposed topology have been investigated in detail. A small-signal model have been derived to analyze the dynamic behavior of the converter. A closed-loop proportional-integral controller has been employed for achieving voltage stability under varying conditions of input and load. Bode plot stability analysis has been applied to the integrated circuit. The converter circuit has been modeled using MATLAB/Simulink with similar operational parameters used to analyze the integrated converter along with the standalone ones. The results obtained show satisfactory voltage regulation, ripple control, steady state response, and dual output power supply operation of the circuit. It is seen that the use of integrated circuits decreases the need of having different converters and improves its efficiency. It can be concluded from the discussion above that the integration of the Buck Converter circuit along with the Negative Output Super-Lift Luo Converter provides an efficient and compact way of supplying low-power EV auxiliary systems with two voltage supplies from a common DC supply.