Design of LED Lighting System for Greenhouse Plant
Résumé
The greenhouse with light emitting diode (LED) is becoming more and more popular for plant growth. A kind of LED lighting system (LLS) is developed in the present study. According to photosynthetically active radiation (PAR), five colors of LED are chosen to satisfy the requirement of plants including red, amber, green, blue and white. The operation principle for dynamic spectrum is analyzed. The system chart, schematic diagram and its basic functions are discussed. The PSoC of Cy8c58LP is adopted as the main control chip. Five driving boxes are used to drive five LED channels. A software is designed with C# language to communicate between the control box and PC through USB. For the thermal management of LED array a water cooling heat sink circulated by motor will be adopted. The operating mode will be determined by the forward current, frequency, duty cycle and period, which can be programmed based on the characteristic of selective absorption light spectrum for certain plant, and then illuminating automatically. Test results show that the maximum driving current can reach to 2.5 A, and the maximum output power of each channel is 60W, totally 300W. Finally, the LLS can dynamically adjust the light quality, quantity and photoperiod to get the optimal light spectrum for plant growth.