混沌频率调制技术在移相全桥变换器抑制EMI的应用

摘要

由于混沌信号的连续频谱的特性，可将其用于开关电源消除开关信号谐波的尖峰，从而抑制EMI。本文提出一种将混沌调制技术应用于移相全桥变换器的方法，该方法利用蔡氏电路设计了混沌信号电路，通过产生的混沌信号驱动开关电源PWM芯片的振荡器，实现开关频率的调制，使原本离散的开关信号频谱拓展到一定的频率范围。仿真结果表明该方法在确保系统稳定的基础上，能实现EMI的抑制。%Chaos has been applied in switch mode power supply (SMPS) , due to its continuous spectrum feature, which is well fit for eliminating electromagnetic interference (EMI) by spreading the spectra of the output signals over the whole frequency band, implying the reduction of EMI. A new method to apply chaotic carrier-frequency modulation in phase-shifted full-bridge converters is presented. Chua's circuit is adopted to design the chaos carrier circuit, which is used to drive the oscillator of pulse width modulation (PWM) IC. Thus, the chaotic carrier-frequency modulation is implemented, and the switching spectrum is spread to a wider range. The simulation results illustrate that the method proposed is effective for EMI suppression.