A Design of a Robust Analog PWM Solar Charge Controller for the Off-Grid Solar Home System: Fixed Frequency Current Control Mode

Abstract

Solar Home System (SHS) is a stand-alone power solution in an isolated area where the national power grid connection is not accessible. Presently using the off-grid solar home system has one solar panel, one lead-acid batter, one PWM Solar charge controller, and 12V DC power operated lamp solutions, fan, television, radio. Various solar home system packages have been introduced so far, which have offered different product features with price variations. Solar home system size is small, so producing energy is insufficient to fulfill the customer's demand. This research paper presented a novel feature analog PWM solar charging techniques through the algorithm of the fixed frequency current mode controller, which also satisfy the requirements of existing off-grid solar home system users to reduce self-power consumption thus purchasing at an affordable cost. This design set up four periods voltage threshold points as a safeguard for the battery to consider battery voltage level, cable length resistance, battery internal resistance, and EMI (Electromagnetic Interference) effects. PWM solar charging improves the charging strategy by protecting against surge voltage and lightning. The study is divided into three sections: solar charging, regulating signals, and voltage comparator. Accordingly, high-sophisticated fixed-frequency current mode controllers are a noise-free switching gate drive signal with simulation data. The design feature also ignores the EMI (Electromagnetic Interference) noise impact on digital IC's input signals.