Research And Design Of LED Street Lamp Driving Power Supply

With the development of China’s urban construction, the scale of road lighting facilities is expanding rapidly.The energy consumption of lighting is rapidly increasing also.The LED lighting is widely used because of its energy saving, environmental protection, long life, easy maintenance and so on.It is important to ease the energy crisis and environment.As the core component of LED lighting, driving power supply is the key to realize efficient LED lighting.Traditional LED drive power efficiency is not so high and non adjustable light, poor performance of constant current. Especially the efficiency is lower in the light load.There is often harmonic pollution to the power grid.In order to solve these problems, this paper focus on a LED lamp drive power which can achieve high efficiency, stability, meeting green energy standards and adjusting light at full load range, with output power of 120 W.This paper briefly discussed the characteristics and principle of LED.Selected the LED street lamp drive circuit topology at all levels and determined the overall structure of LED street lamp drive power based on in-depth analysis and comparison of the existing LED drive circuit.The whole structure have three stages: the first stage is the active power factor correction circuit.Here analyzed and compared the strategy of active power factor correction and determines Boost converter based on the critical conduction mode to realize the APFC function.Designed APFC main circuit and control circuit based on MC33262 in detail.The middle stage is LLC resonant circuit. Firstly pointed out that the shortcomings of the traditional resonant converter,then analyzed the LLC resonant circuit and the working mode.The equivalent circuit model of LLC resonant converter is established by using the method of first harmonic approximation.Voltage gain and impedance curves of the resonant network are obtained.Designed the LLC resonant converter main circuit and control circuit with L6599 controller.The third stage is the constant current driving circuit of Buck. Analyzed and choosed the constant current driving scheme.Designed Buck constant current drive circuit based on the controller LM3404 HV which provides a stable and reliable output current for the LED array.Finally the prototype is made.Experimental test and the result analysis are carried out also. After testing power factor of 0.98, the overall efficiency of 0.92.The circuit achieves the expected design goal at all levels.It shows the theoretical scheme is correct and feasible.