两相并联LCL-nT谐振型多路均流LED驱动器研究

Research on two-phase parallel LCL-nT resonate LED driver with multi-output current sharing

针对大功率发光二极管(LED)应用场合下需要多路输出及各路电流均衡的问题,提出一种具有多路输出均流的两相并联LCL-n T谐振型电路拓扑结构,详细分析两相并联LCL-nT型谐振变换器的恒流特性、多路并联输出的均流特性以及移相调光控制策略;推导出恒流工作频率表达式和能够实现多路均流的负载范围,并对谐振网络的阻抗特性和电压增益特性进行了分析,在此基础上给出一种兼顾输出功率和开关管零电压开关(zero voltage switching,ZVS)的参数设计方法。最后设计1台200 W的实验样机,实验结果验证了所提出的电路拓扑具有良好的恒流特性和均流特性,并且能实现对LED的全范围调光。

A twophase parallel LCLnT resonant converter topology with multioutput current balancing was proposed for the needs of multioutput with current balancing in highpower light emitting diode(LED)applications.The constant current characteristic of the twophase parallel LCLnT resonate converter,the characteristic of parallel multioutput current balancing and the phaseshift dimming control strategy were analyzed in detail;Then the expression of constant current working frequency and the load range were deduced under which the output current is reliably balanced.Meanwhile,the impedance characteristic and the voltage gain of the resonant network were analyzed.Based on it,a parameter design method which balances the output power and zero voltage switching(ZVS)was given.Finally,a200W laboratory prototype was built.The experimental results confirm that the topology presented has good characteristic of constant current and current balancing,and it can realize fullrange dimming of the LED.