A Feedforward Ripple Reduction Control Strategy based on a Hybrid GaN/Si Interleaved Inverter

While wide-bandgap (WBG) devices such as silicon carbide (SiC) and particularly gallium nitride (GaN) offer advantages such as low switching losses and high-frequency switching, they also come with higher cost per current as well as substantially lower overload and fault tolerance. Recent research suggested interleaved operation that the silicon part could take most of the load and WBG contributes only some, while it further compensates distortion. However, such a mode required fast closed-loop control with extreme demands on sensing, filtering, and control bandwidth. Additionally, previous use was limited to dc conversion, where the quasi-stationary output voltage simplifies operation. This paper proposes a novel strategy to reduce the inductor in a hybrid GaN/Si interleaved inverter and use low-bandwidth feed-back control for fundamental current distribution in combination with a feed-forward term based on ripple estimation. This approach decouples high-frequency ripple from low-frequency fundamental currents, achieving fast response and efficient ripple cancellation without the excessive demands of full bandwidth feedback control.