ENERGY SAVING LED-BASED STREETLIGHT SYSTEM

摘要

The energy saving LED-based streetlight system comprises of a subsystem of Real Time Clock (RTC), Ambient Light Sensing (ALS), Temperature Sensor, Power Factor Corrected Constant Current (PFC) LED Driver, Energy Meter Circuit and the Microcontroller Unit (MCU). The RTC includes a pre-programmed yearly cycle settings acquired from a weather bureau for an accurate light triggering during the on state period. It also includes a large capacitance memory backup super capacitor for protecting the critical data needed by the sub-circuit. As part of the system, the Ambient Light Sensing (ALS) monitors the amount of light, which will be analyzed by the Microcontroller Unit (MCU) for light activation. The MCU represents the central control since all of the subsystem is electronically connected to the said controller that decides independently on its next step for proper evaluation of the entire system. Temperature sensors were added to protect the circuits against component stresses and thermal runaway, which play an important role on extending the lifespan of each system, that are being continuously monitored. PFC LED module driver is also applied with analog and digital dimming as exemplary tool on extending the capabilities of the amount of power being used by the light engine. The Energy Meter/Power Sensor gives additional benefits by monitoring the actual total amount of power consumed by the whole circuit and sends back the information to the MCU for possible assessment to determine the irregularities on each system.