上海科技大学知识管理系统

In residential photovoltaic (PV) systems, microinverters link the PV panels to the ac bus. Conventionally, these microinverters incorporate a stable dc bus that relies on bulky electrolytic capacitors. To improve, we propose an adaptive virtual bus strategy for DAB microinverter,which removes the electrolytic capacitors. The microinverter features a quasi-single-stage design interconnected by a virtual bus that exhibits a notable double linefrequency voltage ripple. The front-end employs a Boost converter, to elevate the low PV voltage and regulate the voltage of the virtual bus. The back-end utilizes a dualactive- bridge (DAB) inverter to transform the oscillating virtual bus voltage into the desired ac output. This architecture facilitates adaptive power decoupling (APD) for enhanced power density by buffering mismatched power on the minimized bus capacitors and dynamically adjusting the operational state of the DAB inverter. Furthermore, by decoupling the control algorithms of the two parts, we reduce the number of required voltage and current sensors, thereby simplifying the overall control system. To validate the concept, a GaN-based prototype rated at 200W and 600kHz maximum is designed and tested. This prototype achieved a peak efficiency of 92.67%.