A resonance suppression method for GaN-based single-phase quasi-Z-source PV inverter with high switching frequency

By utilizing next-gen wide band-gap (WBG) devices, such as GaN and SiC, at high switching frequency in a single-phase Quasi-Z-Source PV inverter (qZSI), the impedance network can be significantly reduced. Although, the reduced qZS impedance network will decrease cost and improved power density, it will also result in frequency resonance that will introduce oscillations in the capacitor voltage and increase system losses. Thus, these resonances must be properly mitigated. Traditional methods only apply to two-stage power conditioning systems and/or require a low voltage control bandwidth, which is unsuitable for the GaN-based qZSI. Therefore, this paper proposes an active damping control method to suppress the high frequency resonance that results from the reduced impedance network in a single phase qZSI. A 1-kW prototype is built and experimental results verify the effectiveness of the proposed control method.