Compressor speed control for optimizing energy matching of PV-driven AC systems during the cooling season

Photovoltaic-driven air conditioning (PVAC) systems innovatively utilize PV power for building cooling, reducing PV power fluctuation impact on the utility grid. This study introduced a novel PVAC system that optimizes the energy matching between PV generation and air conditioning electricity demand through directly controlling of the compressor speed in accordance with the real-time PV power generation. A PID control method was employed to regulate the compressor speed of PVAC, and three control strategies were proposed and successfully implemented during the experiments. The system's efficiency was evaluated using metrics such as the self-consumption rate (SCR), self-sufficiency rate (SSR), real-time zero energy proportion (RZEP), and the mean absolute error (MAE) of indoor temperature. The results of this study confirm that the proposed control method significantly enhances the power matching between the PV power generation and the air conditioning electricity demand. Implementing the recommended strategy, SCR increased from 0.53 to 0.625 and SSR from 0.716 to 0.808, all while maintaining indoor thermal comfort. Moreover, the proposed approach mitigates the impact of distributed PV generation on the utility grid and potentially diminishes energy storage needs, which can contribute to a lower system investment requirements and operating costs.