Research On Novel High Power Density Driver For LED

The research on effective and environmental-friendly electric product plays an important role since green lights idea coming into our life. In lighting field, LED(Light Emitting Diode) is a new type one with effective, energy saving, environmental-friendly, long life span and reliable advantages. Many countries speed up the research on LED lighting products and its driver.In this thesis, the two power stages driver is compared with three power stages one. Then a new high power density LED driver is proposed by integrating the PFC circuit and the DC/DC converter. This type of LED driver shrinks the size, increases the power density and lowers the cost. And two types topology of high power density driver are designed and compared by theory analysis and simulation.The SF-SPS converter proposed in this thesis can bring about soft switching, therefore it can work at high frequency and have higher power density. The condition of Sepic achieving PFC and Flyback bringing about zero-current and low voltage switch turnned on is analysed, and the clamping circuit and compensating network is designed respectively. Moreover, the equivalent circuit model is build and its control circuit is optimized. The SP-SPS convertor controller is designed by analog and digital combination. The control method employs two closed loop control using zero voltage turn on and peak current turn off.An 100W SF-SPS experimental sample is established and debugged. Following tests Steady-State efficiency of the proposed SF-SPS converter is higher than 83%. The power factor is greater than 0.991, THD is less than 9% and the load regulation is 3.4% when the load veries from 30% to 100%. While the power factor is greater than 0.988, THD is less than 10% and the voltage regulation is 3.9% when the input voltage veries from 180V to 260V. Experiment results indicate that the designed SP-SPS converter is provided with good dynamic and steady performance.