【摘要】 混沌信号具有类随机、连续频谱的特性,混沌调制用于直流开关变换器可以扩展频谱,抑制电磁干扰(EMI)。但实际产生的混沌信号频谱具有一定的范围,如由蔡氏电路产生的模拟混沌信号,具有一个特殊频率并以之为中心左右基本对称的频谱范围,这个频率为中心频率并由电路的实际参数所决定。本文以BUCK变换器为例,采用外接蔡氏电路作为模拟混沌信号发生器,分别选用合适中心频率的混沌信号,实施混沌化占空比和混沌化频率的方案,通过计算机仿真结果进行对比,验证了混沌调制具有改善电磁兼容(EMC)的性能,且混沌化频率的方案抑制EMI效果更明显。更多还原

【Abstract】 Chaos modulation was applied to suppress electromagnetic interference(EMI) in DC converters by expanding the spectra because the chaotic signal has characteristics of pseudo random and continuous spectrum. Actually the frequency band of chaotic signals is limited by its generator. The analogue chaotic signal produced by Chua’s circuit has its oscillating frequency centered at the limited band, which is decided by the parameters of some components, such as the inductor and the capacitors. With BUCK converters as an example, two different schemes of chaos modulation with an external Chua’s circuit were designed. As the result, the chaotic duty and the chaotic frequency of PWM were verified to flatten the amplitude of the fundamental and harmonics of the switching frequency in the simulation with Saber 7.0. It should be pointed out that the latter was better to reduce EMI, though some ripples appeared in output voltages.更多还原