高电压宽范围输入低电压输出的DC-DC辅助电源设计

Design of Wide-Range High Voltage Input Low Voltage Output DC-DC Auxiliary Power Supply

高电压宽范围输入的DC-DC辅助电源技术是中高压、大容量电力电子变流系统的关键辅助技术。基于双管反激电路,本文设计了一个高电压宽范围300~2 500V输入,低电压24V输出的DC-DC辅助电源样机,并给出了电源详细的设计方案。相比传统辅助电源,设计的辅助电源启动支路在电源工作后可自动断开,实现了电源输入电压范围更宽目标;电源主电路由变压器隔离,控制、反馈电路由辅助绕组供电,确保了电源输入/输出高电压隔离;开关管驱动电路采用带耦合电感的脉冲变压器,满足了驱动信号高压隔离和同步驱动要求。此外,计算电源效率的结果表明,双管反激辅助电源更适合高电压输入场合。最后,进行了相关实验,结果验证了所设计的高电压宽范围输入的DC-DC辅助电源方案可行性和正确性。

The use of high-voltage and wide-range DC-DC auxiliary power supply for the medium-high voltage and large-capacity power electronic converter system is a key auxiliary technique. Based on the double-transistor flyback circuit, the paper presents an auxiliary power supply prototype with a high-voltage, wide-range 300V^2 500 V input and a low-voltage 24 V output, and offers a detailed design scheme for the auxiliary power supply. Compared with the conventional auxiliary power supply, the designed auxiliary power supply start-up branch can switch off automatically when auxiliary power works, achieving the purpose of a wider-range power input. To satisfy the demand of the isolation of high-voltage power supply input and low-voltage output, the feedback circuit voltage is to be obtained from auxiliary winding. The drive scheme for auxiliary power supply refers to the adoption of the transformer gate drive with coupling inductance balance kernel, thereby satisfying the two-tube driver signals high-voltage isolation and improving the synchronism of drive signals. Moreover, the result of calculating the efficiency of the auxiliary power supply indicates that the auxiliary power supply is more suitable for high-voltage input. Finally, the related experiments done on the auxiliary power supply verify that scheme designed for the auxiliary power supply with high-voltage input and low-voltage output is practicable and correct.