Chaotic PWM spread spectrum scheme for conducted noise mitigation in DC-DC converters

Electromagnetic interference is the important problem associated with the electromagnetic field. The sources of EMI may be natural sources, like atmospheric charge/discharge phenomena and extraterrestrial radiation, or may be man-made sources, like power lines, auto ignition, radio frequency interference, and radiation hazards etc. As important components, direct current (DC-DC) converters are embedded and employed in various electrical devices, thus forming main sources of EMI. Some measures, such as filters and electromagnetic shielding, have been taken to suppress EMI, but these methods have various drawbacks with respect to cost, volume, weight, and efficiency. Therefore, new theories and methodologies are desired to cope with the EMI problem. Spread Spectrum Technique or chaos control is an important method due to the continuous spectrum feature. This paper describe two methods to implement the Spread Spectrum Technique in a Boost Converter. An analogue chaotic carrier is designed to be embedded in a chaotic pulse width modulation (PWM) boost converter, and to be used for reducing electromagnetic interference (EMI) in dc-dc converters. Simulations study is conducted to illustrate the effectiveness of the proposed analogue chaotic PWM in reducing EMI. Randomized carrier frequency modulation with fixed duty ratio (RCFMFD) Spread Spectrum scheme for pulse width modulation (PWM) boost converter, is implemented using Field Programmable Gate Array (FPGA) technology. The simulations and experimental verification is done, so as to prove the effectiveness of Spread Spectrum scheme in reducing the electromagnetic interference (EMI) in dc-dc converters.