分时复用控制多路输出开关电源

针对传统的电压型PWM单反馈支路控制多路输出开关电源存在的非反馈支路调节性能差,以及输出支路之间存在交叉影响的问题,采用反激式变换器实现单输入三输出电压,同时引用电压型分时复用控制方法,从而得到稳定可靠的5V、15V、24V三个输出电压等级。详细介绍了主功率电路和控制电路的工作原理,并分析了在DCM(电流不连续模式)下反激变换器三种工作状态的交流小信号动态特性,进而建立了控制对象的开环传递函数并对其进行了仿真分析。分析可知,其低频段斜率为0dB/dec,不能实现无静差;高频段斜率为-20dB/dec,抗干扰能力差。基于此,在电压型控制回路中增加一个单极点—单零点补偿网络后,低频段斜率提高到-20dB/dec,高频段斜率提高到-40dB/dec,从而改善了系统输出性能。最后通过MATLAB软件搭建了分时复用控制多路输出开关电源的模型并进行了仿真,仿真分析可知针对此拓扑电路结构所采用的电压型分时复用控制方法能够得到稳定的、可靠的和调节性能较好的三路输出直流电压。

TIME- SHARING MULTIPLEXING CONTROL MULTIPLE OUTPUT SWITCHING POWER SUPPLY

Due to poorly regulated performance of non-feedback branches and influence of cross between output branches of the traditional voltage-type PWM control which controlled multiplexed output switching power supply,the paper implemented the single input and three output voltage based on flyback converter,at the same time, adopted time-sharing multiplexing control method of voltage-type when controlled,so as to obtain stable and reliable three levels of voltage 5V,15V,24V.Which introduced the working principle of main power circuit and control circuit in detail,in addition,analyzed the AC small signal dynamic feature of the three kinds working conditions of the flyback converter when it worked in the DCM (Discontinuous Current Mode), thereby established open loop transfer function of the control object and carried simulation analysis.which showed that the low frequency band slope of 0dB/dec, can not achieve astatic; high frequency band slop of -20dB/dec, anti-interference ability is poor. Based on this, the paper added a single pole-single zero compensation network in the voltage control loop,as a result,low frequency slope up to -20dB/dec, high frequency slope up to-40dB/dec,output performance of this system was improved.Finally built a model of time-sharing multiplexing control multiple output switching power supply and carried simulation by matlab software and the result showed that the voltage type of time-sharing multiplexing control method can get stable and good regulated performance of three way output switching power supply.