Solar Energy Based Self-Sustainable Power Management System

Frequent battery replacement is a big challenge faced in Wireless Sensor Nodes (WSNs) operating in remote places due to high maintenance cost and inaccessibility. The solution for this is harvesting energy from various sources like solar, wind, thermal, vibration. Solar energy harvesting is the best option among them because of its abundant availability. The battery gets charged through solar energy during daylight and when solar energy is not available, the system gets power up through the charge stored in the battery. The Maximum Power Point (MPP) of the solar cell is tracked by comparing the MPP voltage with respect to the input solar cell voltage. The reference MPP voltage is generated by sampling 0.7 times the open circuit voltage (VOC ) of solar cell periodically in a capacitor (CMP P ). A self sustainable high power battery management system is developed where the system works in two modes, the first one is the main converter mode and the second is the startup mode. startup mode is used when the battery is almost drained. None of the other control circuitry function in this mode. Cold start circuit only goal is to charge output capacitance until it crosses the threshold voltage required to power the entire system. Power On Reset (POR) circuit decides between startup mode and main converter mode