Analysis of power conversion efficiency in boost and LLC resonant converter-based solar water pumping systems

Abstract This paper investigates the feasibility of employing an LLC resonant converter in a high-efficiency Solar Water Pumping System (SWPS) as an alternative to the conventional boost converter stage. The proposed system integrates maximum power point tracking (MPPT), PI-based DC-link regulation, and V/f control of an induction motor to maintain optimal performance under varying solar irradiance conditions. A detailed MATLAB/Simulink model was developed and experimentally validated using an OPAL-RT 4510 hardware-in-the-loop (HIL) platform. The LLC converter operates at 10 kHz, while the motor frequency is varied between 0–50 Hz to track irradiance-dependent reference speeds. Stagewise power flow analysis was conducted at irradiance levels of 1000, 500, and 300 W m −2 , comparing both boost and LLC topologies. Results indicate that the motor effectively follows the reference speed without overcurrent, and the LLC-based configuration achieves soft switching with a modest efficiency improvement from 83.9% to 85.7.0% over the conventional boost design. While the LLC approach may involve higher component costs, the study demonstrates its potential to enhance energy conversion efficiency, reduce switching losses, and improve operational reliability, providing insights into next-generation solar pumping solutions.