The solar-LED streetlight controller described in this application note is designed to achieve an 85 W solar energy battery charger and a 25 W LED lamp driver. During the daytime, the controller preserves the electricity energy gathered by the solar module (PV module), then stores it in the battery. In the evening, the controller uses the battery energy to power the LED streetlight. When the battery runs out of power after several rainy days, the controller enables the external offline power supply (not included in this system) instead of the battery to power the LED streetlight until the system battery is fully charged again. Due to the clean nature of solar energy, and the highly efficient energy conversion of the PV module and very long operating life of the LED lamp, the solar-LED streetlight controller, compared to conventional streetlights, can save electricity remarkably, thus abating greenhouse gas (e.g. CO2) emission.
The document details a solar-LED streetlight controller solution designed to manage energy from a PV module for charging a battery during the day and powering an LED lamp at night. The system includes an external offline power supply that activates when the battery is depleted after several rainy days.
The architecture relies on the STM32F101Rx microcontroller to implement hardware and firmware design, including Maximum Power Point Tracking (MPPT) for the battery charger and constant current control for the LED driver. The note covers safety instructions, system architecture, circuit descriptions, test results, and firmware logic.
The controller preserves electricity energy gathered by a solar module and stores it in a battery, then uses that battery energy to power an LED streetlight.
The controller enables an external offline power supply instead of the battery to power the LED streetlight until the system battery is fully charged again.
An MPPT (maximum power point tracing) algorithm is applied to enable the PV module to output as much electricity power as it can.