CCM开关变换器离散滞环电容电流脉冲序列控制方法

Discrete Hysteretic Capacitor Current Pulse Train Control Method for CCM Switching Converter

针对传统脉冲序列PT(pulse train)控制连续导电模式CCM(continuous conduction mode)开关变换器存在的低频振荡问题,提出了一种离散滞环电容电流脉冲序列DHCC-PT(discrete hysteretic capacitor current-pulse train)控制方法。DHCC-PT控制方法通过限制每一个开关周期起始时刻电容电流i_(C)(nT)的运动区域,将其控制在不易发生低频振荡所对应的电容电流边界区间内,即可实现低频振荡的有效抑制。以CCM Buck变换器为例,详细阐述了DHCC-PT的基本原理、控制流程以及低频振荡抑制机理,设计了简单可靠的DHCC-PT控制器实现电路,并通过仿真和试验对其控制规律和输出特性进行了研究,验证了控制方法的可行性和理论分析的正确性。研究表明:DHCC-PT控制方法简单有效,DHCC-PT控制CCM开关变换器具有良好的输出电压特性。

For the problem of low-frequency oscillations existing in a conventional pulse train(PT)controlled switching converter operated in continuous conduction mode(CCM),a discrete hysteretic capacitor current-pulse train(DHCC-PT)control method is proposed in this paper.The effective suppression of low-frequency oscillations can be achieved by limiting the moving region of the capacitor current i_(C)(nT)at the beginning of each switching cycle such that i_(C)(nT)can be controlled within the boundary region where low-frequency oscillations can be avoided.A CCM Buck converter is taken as an example,and the operation principle of DHCC-PT,the control flow chart and the suppression mechanism for low-frequency oscillations are analyzed in detail.In addition,a simple and reliable DHCC-PT controller circuit was designed,and its control law and output characteristics were studied through simulations and experiments,which verifies the feasibility of the control method and the correctness of theoretical analysis.Research results show that the DHCC-PT control method is simple and effective,and the CCM switching converter controlled by DHCC-PT has satisfying output voltage characteristics.