Chaotic systems are widely used in image encryption, but their application in converters is relatively underexplored. In order to study such problems, this paper introduces a novel chaotic system based on the Lorenz system, and investigates its chaotic properties through the Lyapunov exponent, bifurcation diagram, coexisting attractors, intermittent chaos, Poincaré section and complexity analysis. A buck converter based on the proposed chaotic circuit as a spread spectrum signal is constructed to suppress Electromagnetic Interference (EMI) noise. By using a Voltage-Controlled Oscillator (VCO) and a Sawtooth Wave (SAW) generator, a frequency-modulated Pulse Width Modulation (PWM) signal is created, which can control the turn-on and turn-off of the controllable switch to keep the DC–DC switching converter working properly. Compared with existing approaches using other modulation signals, it is found that the proposed method can suppress EMI more effectively. This confirms that the new chaotic system can be applied in converter, providing a promising solution for reducing EMI noise in electronic devices. To verify the theoretical analysis, the converter is studied using a time-domain circuit simulation software and circuit implementation, which shows that this method achieves EMI noise suppression exceeding about 16Formula: see textdB compared to a buck converter without applying the chaotic spread spectrum technology, and that the new model has better effect than the classical Lorenz system.
Sun et al. (Sat,) studied this question.