Volume 2 - Issue 2, March - April 2026

This paper presents the complete hardware design and implementation of a battery-less solar energy utilization system employing an Auxiliary Power Unit (APU). The core problem addressed is the automatic shutdown of grid-tied solar inverters during utility grid outages — a safety feature that, paradoxically, wastes available solar energy precisely when it is most needed. The proposed solution deploys a purpose-built APU, based on the EGS002 SPWM driver board incorporating the EG8010 sinusoidal PWM IC, to generate a stable 50 Hz, 220 V AC reference signal that simulates grid presence and keeps the main 200 W inverter operational. A 50 W, 21.13 V photovoltaic module powers the APU; an Arduino Nano microcontroller monitors system state via ZMPT101B voltage sensors and ACS712 current sensors, and controls a DPDT electromagnetic relay for seamless source switching. Experimental results confirm that the system sustains uninterrupted power delivery to household loads — verified with an ORNAT 1-phase static energy meter — during simulated grid outages, with zero battery storage required. Component ratings, design calculations, and performance observations are reported in full.

Prof.L.M.Bopche, Om Jakkulwar, Pravin Agashe, Sahil Katkade, Surbhi Dhande, Yugantari Nagpure,"Solar Energy Utilization with Auxiliary Power Unit" International Journal of Advanced Multidisciplinary Research and Educational Development, V2(2): Page(1461-1467) Mar-Apr 2026. ISSN: 3107-6513. www.ijamred.com. Published by Scientific and Academic Research Publishing.