An adaptive PID control method to improve the power tracking performance of solar photovoltaic air-conditioning systems. (October 2019)

• Record Type: Journal Article
• Authors: Zhao, B.Y.; Zhao, Z.G.; Li, Y.; Wang, R.Z.; Taylor, R.A.
• Is Part Of: Renewable & sustainable energy reviews. Volume 113(2019)
• Publication Date: 2019-10
• Subjects: Solar photovoltaic -- Air-conditioning load -- Power tracking -- Indoor comfort -- Adaptive control; Renewable energy sources -- Periodicals; Power resources -- Periodicals; Énergies renouvelables -- Périodiques; Ressources énergétiques -- Périodiques; 333.794
• DOI: 10.1016/j.rser.2019.109250
• Languages: English
• ISSNs: 1364-0321

Abstract

Abstract: In order to increase the utilization of solar energy to lower the effect of photovoltaic power output fluctuations on power grids, an adaptive PID control method to improve the power tracking performance of solar photovoltaic air-conditioners is proposed in this paper. In this method, a dynamic temperature set point of the indoor zone is generated at each control time step based on the difference between the air-conditioning load and photovoltaic generation. The theoretical analysis shows that the proposed control is essentially a feedforward feedback control where the air-conditioning system can predictably adjust the compressor frequency based on the knowledge of how the solar radiation affects the cooling load. A case study in Shanghai shows that the proposed control method is able to significantly improve the power tracking performance of the photovoltaic air-conditioner, where the Solar Fraction ( SF ) and the Self-Consumption Ratio ( SCR ) are improved from 82.74% to 88.11% and from 70.12% to 74.42% respectively, without violating the indoor thermal comfort, where Mean Absolute Error ( MAE ) from the temperature set point is decreased from 0.197 to 0.168. The tuning of the power difference factor k o will lead to monotonic changes of SF & SCR and a minimum MAE . When k o is well tuned, the proposed control can realize desirable system improvements of both the power tracking ability and the indoor temperature control accuracy. The idea of this paper could be easily modified to benefit other solar cooling applications and conventional air-conditioners. Highlights: Reduction of the power gap between air-conditioning load and PV generation. PID based control to make real-time, dynamic adjustment feasible. Higher indoor temperature control accuracy than normal PID controls. Applications on other solar cooling systems and conventional HVACs.