Boost变换器断续导通模式的PSM同步开关映射模型

S-switching Mapping Model of PSM in DCM Boost Converter

平均法是分析各种PWM模式DC/DC变换器的基础,其缺点是各种非线性信息遗失在平均过程中,因此研究PWM变换器非线性现象需要建立正确的离散映射模型。跨周调制(PSM)作为一种新的调制模式,具有响应速度快,轻负载转换效率高等优点,已在小功率单片IC中得到广泛应用,但PSM模式的非线性离散映射模型未见报道。该文建立断续导通模式(DCM)Boost变换器的同步开关映射模型,并根据该模型详细分析PSM调制的非线性现象。研究表明PSM调制模式下,参数的变化引起系统的输出在定常解和周期解之间变化,变化呈现无序性,但系统一直保持稳定的输出,说明PSM具有较强的鲁棒性;最后将PSM的非线性现象与PWM的分叉与混沌现象进行比较,对产生二者区别的原因给出了合理的解释。

Averaged method is the basis of analyzing all PWM DC/DC converters. But all nonlinear information will be lost in averaging process. So, it is necessary to set up an accurate discrete-time mapping model when We study the nonlinear phenomena of PWM converters. As a new modulation mode, PSM has many advantages such as quick response, high conversion efficiency at light loads, which has been widely applied in small power IC. However, the nonlinear discrete-time mapping model of PSM has not been proposed. So, this paper proposed an S-switching mapping model of PSM for DCM Boost converter. According to this model, the nonlinear phenomena of PSM are discussed in detail. The research results show that the system output varies out of order, but stably, between fixed solution and periodic solution with the changes of parameters. Therefore, PSM has strong robustness. Finally, the rational explanation of difference, compared with PWM bifurcation and chaos, is also presented in this paper.