用于单电感双输出Buck变换器的PCPV控制方案

Peak-Current and Peak-Voltage Control Scheme for Single-Inductor Dual-Output Buck Converter

为减小工作于连续导电模式(continue conduction mode,CCM)的单电感双输出(single-inductor dualoutput,SIDO)Buck变换器的输出交叉影响,提出了峰值电流-峰值电压(peak-current and peak-voltage,PCPV)控制方法.分析了PCPV控制SIDO Buck变换器的电路结构和工作原理,利用电感伏秒平衡和电容安秒平衡原理推导了输出电压与输入电压的增益表达式,并采用状态空间平均方法,建立了PCPV控制SIDO Buck变换器的状态空间平均模型;在此基础上,建立了PCPV控制SIDO Buck变换器的小信号模型,并与传统峰值电流(peakcurrent-mode,PCM)控制SIDO Buck变换器对比分析交叉影响.研究结果表明:PCM控制SIDO Buck变换器输出电压较大的输出支路对输出电压较小的输出支路的交叉影响为300 mV,而PCPV控制SIDO Buck变换器输出电压较大的输出支路对输出电压较小的输出支路几乎无交叉影响;PCM控制SIDO Buck变换器的负载瞬态调节时间为12.5 ms,而PCPV控制SIDO Buck变换器的负载瞬态调节时间最大为10 ms.相比PCM控制SIDO Buck变换器,PCPV控制SIDO Buck变换器有效地减小了交叉影响,且提高了瞬态性能.最后通过实验结果验证了理论分析的正确性.

In order to reduce the output cross regulation of single-inductor dual-output(SIDO)buck converter in continuous conduction mode(CCM),a peak-current and peak-voltage(PCPV)control method is proposed.The circuit structure and operating principle of the PCPV-controlled SIDO buck converter are analyzed.The gain expressions of input voltage and output voltage are deduced according to the principle of inductor volt-second balance and capacitor ampere-second balance.The state space average model of PCPV-controlled SIDO buck converter is established by using the state space average method.On this basis,the small signal model of PCPVcontrolled SIDO buck converter is established,which is compared with traditional peak-current-mode(PCM)controlled SIDO Buck converter in the cross regulation.The research results show that the cross regulation from the higher voltage output branch to lower voltage output branch of PCM controlled SIDO Buck converter is 300 mV,and its transient regulation time of load variation is 12.5 ms.However,the proposed converter can reduce the cross regulation to almost zero and reduce the transient regulation time to 10 ms.Compared to the PCM controlled SIDO buck converter,the proposed PCPV-controlled SIDO Buck converter can effectively reduce the cross regulation and improve the transient performance.Finally,the theoretical analysis of the proposed method is verified by experimental results.