Development Of Classroom Led Lighting Power Supply System Based On Three Cables Dc Offset Pattern

With the rapid development of city modernization and the popularity of much low voltage electrical equipment, for example, LED lamp, printer, microwave oven and many other household appliances, traditional AC power supply system can cause a large number of harmonics and produce serious electromagnetic radiation. This method has bad effect on power quality. While low voltage direct current (LVDC) can reduce the power loss effectively, improve the efficiency of power transmission on the cable, reduce electromagnetic radiation and improve the power quality. At present, energy-efficient LVDC power supply system is one of the most important fields for research scholars and one of the most significant practical directions in the engineering application. It must be more and more advantageous and play a large role in the rapid development of new technology revolution.This dissertation puts forward the classroom LED lighting power supply system based on the pattern of three cables DC offset. This power supply system introduces a compensation cable on the basis of unipolar double cables power supply system, it can utilize the compensation cable and low voltage electrical energy converter to recoup the cable loss automatically, compensation range is 3V-18V, the amplitude of compensation voltage is small. This method reduces the switch pulse amplitude greatly, thus minimize electromagnetic interference and provide compensation power to the load, compensation power is about 0.1W～1W, this power range can ensure the normal brightness. LVDC power supply system based on the pattern of three cables DC offset replace high voltage DC-DC converter and high voltage filter capacitor in traditional LED driving power supply to low voltage DC-DC converter and low voltage filter capacitor, so it reduce the noise in the power port and electromagnetic radiation.The classroom LED lighting power supply system based on the pattern of three cables DC offset, consist of one host and many extension sets, adopts unipolar LVDC power supply. The host is mainly composed of high power APFC, intelligent output voltage proportional divider and three power cables. Extension set consists of low power automatic compensation power supply based on KA34063 and LED units.This dissertation makes theoretical analysis, simulation and experimental verification to the proposed LVDC power supply system. The transmission power is improved greatly compared to AC power supply system. The extension set can provide small power efficiently to compensate cable loss. The system can reduce the electromagnetic radiation consumedly.The design and implementation of energy-efficient LVDC LED lighting power supply system with three cables will improve the unipolar power supply system and enrich the practical scheme of LVDC power supply system. It has very good feasibility in the aspect of reducing the power supply noise and electromagnetic radiation, and can provide certain reference and experience to the design of LVDC power supply system in the same filed.