基于变频数字控制多谐振直流变换器研究

Variable Frequency Digital Control Strategy Investigation of Multi-resonant LLC Converter

传统LLC谐振变流器拓扑具有初级开关易实现全范围的ZVS,次级二极管易实现ZCS,谐振电感和变压器易实现磁集成,以及范围宽等优点,因此得到了广泛关注。本文把基于TMS320LF2407的增量PID数字式变频控制方案用于该变换器,借助数字控制的灵活性,使得电路调试方便易行,在额定电压输出时,开关工作频率为100～160kHz。文中给出倍压输出的功率主电路和数字信号处理器(DSP)控制电路。最后给出模块样机的实验波形。

The prominent merits of conventional LLC resonant topology can be specified as follows, realization of full range of ZVS for primary switches and ZCS for secondary diodes,easy integration of resonant inductor and transformer, wide range operation.The topology is focused on due to the above advantages.Strategy of increment mode digital PID variable frequency control, which is based on TMS320LF2407, is adopted for controlling the operation, and that the flexibility of digital control facilitates modulation process. Consequently, for wide range input, once output reaches the reference value,range of switching frequency is 100kHz to 160kHz.Vohage-doubler output of main topology and control circuit based on DSP are given in the paper.Finally, experimental waveforms of the prototype are illustrated.