Mitigation of Conducted Electromagnetic Noise of DC–DC Converter by a Novel Inductor–Diode Based Circuit Technology

This article presents a novel and efficient inductor–diode-based technique to mitigate the high-frequency conducted electromagnetic interference (EMI) noise, which has not been reported in the literature so far. It targets the high-frequency conducted EMI peaks that fall in the frequency range, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{2} \,{\mathrm{MHz}}$</tex-math></inline-formula> - <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{30} \,{\mathrm{MHz}}$</tex-math></inline-formula>, by distributing the high-frequency noise peak energy into several frequencies. Thus, it restricts the high-frequency oscillation generated due to the switching transients of the converter. In the proposed technology, a parallel combination of inductor and diode is connected in series with the dc-link capacitor of the converter. The inductance value is inversely proportional to the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$di/dt$</tex-math></inline-formula> of the converter switch and remains below 100 nH. The power dissipated in the diode is around <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$0.05 \,\%$</tex-math></inline-formula> of the converter power rating, and its blocking voltage is less than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{5} \,\%$</tex-math></inline-formula> of the dc-link voltage. Thus, the inductor and diode are smaller in size and cheaper in cost. The proposed technology has been experimentally validated on a SiC-<sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> based <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{1} \,{\mathrm{kW}}$</tex-math></inline-formula> dc–dc converter. The input voltage and current for the converter are <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{200} \,{\mathrm{V}}$</tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{5} \,{\mathrm{A}}$</tex-math></inline-formula>, respectively. The proposed technique achieves <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{16} \,{\mathrm{dB}}$</tex-math></inline-formula> reduction of the noise peak at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{26} \,{\mathrm{MHz}}$</tex-math></inline-formula>.