PV Powered LED Street Lights Optimization Using Zeta-Sepic converter and Photo-Electro-Thermal Theory

Nowadays, using the photovoltaic powered LED street lights are spreading due to their higher efficiency and longer lifetime. In this paper, the Zeta-Sepic converter is used to manage the LED light, the PV panel and a battery storage in these systems, since it offers compact and single-stage power conversion. The PV panel and LED light connect to the converter input port using simple relay, while the battery source puts at the converter output port. During the day, the PV panel energy saves in the battery through the converter forward direction power flow. Besides, in the reverse direction power flow of the converter the battery supplies the LED light required power during night. For these operation cases, voltage regulation is realizable at the both converter input and output ports. This performance provides MPPT to the PV panel, SOC for the battery and light control with the LED light. For LED lights, there exist a relationship between light, electricity and thermal that is optimized to achieve the luminal flux to the input power highest ratio. As a result, this paper uses the photo-electro-thermal theory, heatsink characteristics and bidirectional Zeta-Sepic converter to drive the LED lights at the operating voltage, in which the LED light optimal luminous flux occurs. Finally, the proposed system is analyzed and validated in different operation conditions using MATLAB/SIMULINK. Also, photo collector sphere was built in the laboratory that is able to achieve the optimal working point of the light by measuring the photo through sensors installed on it.

Keywords:

LED street lights , Photovoltaic system , PET theory , Zeta-Sepic converter , Photo collector sphere