Research On LED Intelligent Control System Based On Zigbee Wireless Network

In recent years,LED has become a new generation of green light source by its good performance.It has been widely used in road lighting,tunnel lighting and other high-power lighting applications.And the efficient and reliable LED driver is the key to ensuring stable work of the LED.With the development of science and the improvement of living standards,people require intelligent control,simple operation,energy efficient while meeting the demand of basic lighting.Thus,LED intelligent control system based on Zigbee wireless network comes into being.Firstly,this paper introduces the developing status of high-power LED driver,including the structure of LED driver,multi-channel current balancing technology and dimming technology and so on.Then analyzing the circuit characteristics and the advantages and disadvantages of LED drivers based on half-bridge LLC and half-bridge LCL-T resonant converter.For the high-power LED applications,we propose a novel LCL-T resonant converter topology with multiple output current balancing,which can achieve a balance among each output current when the LED lamp voltages are different.The paper analyzes the working process,constant current characteristic and the current balancing principle of the circuit.Then deducing the relationship between the constant current point and the working frequency,analyzing the effect of the resonance parameters on constant current working frequency,and also giving the key parameters design method.At the same time,it studies a two-phase parallel LCL-T resonant converter which can be used in high-power lighting applications,and analyzes the circuit characteristics and working principle of the converter.Based on this,a phase-shift dimming control strategy is proposed,which realizes the control of the full range smooth dimming of LED lights.Doing a detailed analysis of the working principle of the dimming strategy,and deducing the relationship between the phase-shift angle and the output current's RMS.At last,giving the specific implementation method of the circuit,and verifying the feasibility of the circuit by simulating on saber software.For the requirement of the intelligent control of LED lighting system,we put the Zigbee wireless network into the LED driver and then design a LED intelligent control system based on Zigbee wireless network,according to the design of intelligent control system requirements and the characteristic of Zigbee technology.Giving the specific implementation method of the intelligent lighting control system,and verifying the feasibility of the scheme proposed by experimentions.Finally,a 200W LED driver experimental prototype using dsPIC microcontroller as the main controller with four outputs current balancing and Zigbee dimming is developed.Making the experimental testing of the prototype,the experimental results verify that the proposed scheme is feasible.