三相IGBT全桥隔离驱动电源设计

摘要

设计了一种基于电流型PWM控制器UC3845的三相IGBT全桥隔离驱动电源.采用单端反激式结构,电压反馈与电流反债组成双闭环串级结构.TIA31a与PC817组成反馈网络,旁路掉UC3845内部误差放大器,反馈信号直接输入到内部误差放大器的输出端.提供4路相互隔离输出,每路均提供+15V/-9V*出.该电源稳压效果好,负载调整率高,适合作为三相IGBT全桥隔离驱动电源.%An isolated power supply based on UC3845 for three-phase IGBT full-bridge driving circuit is designed. The form of single-ended fly-back is used. Voltage and current feedback form the double-loop cascade structure. The TLA31a and PC817 are combined to form a feedback network, bypass the internal error amplifier of UC3845. The feedback signal is directly input to the output terminal of the intemal error amplifier. Providing a total of four isolated outputs, each of them consists of +15 V /-9 V outputs. This power supply has stable output voltages. high load regulation rates. It is suitable as threephase IGBT full-bridge isolated driving power supply.