A quasi-periodic modulation strategy to mitigate EMI for a GaN-based quasi-Z-source DC-DC converter

Wide-bandgap (WBG) switching devices, such as gallium nitride (GaN), enable switching at high frequencies with low rise and fall times. This provides advantages such as high power density and compact size, however a potential unwanted side-effect is increased electromagnetic interference (EMI) because of large transient currents. A novel quasi-periodic modulation scheme is described for voltage-fed quasi-Z-source (qZS) DC-DC converters which substantially reduces the peak EMI. The driver logic required is simple and generic, and therefore adaptable to all modulation schemes proposed to date for isolated qZS DC-DC converters. Various experimental results verify the effectiveness of the proposed strategy in terms of voltage gain, efficiency and EMI suppression.