Modelling and control stability analysis of grid-connected bifacial PV power generation systems using virtual synchronous generator technology

In recent years, bifacial solar panels are accelerating to replace single-side PV devices in traditional PV power generation system due to their high utilisation rate and price advantages. This makes the stability and control strategy of grid-connected bifacial PV systems (GCBPVS) to be different from the traditional method after it is connected to the power systems. This paper fully considers each detailed module in GCBPVS using virtual synchronous generator (VSG) technology and derives the small-signal model of the fully grid-connected (GC) system using the linearisation method of each sub-module. Then, it analyses the small disturbance stability and oscillation mode characteristics of GCBPVS by combining the effects of partial system parameters change on eigenvalues. Especially for the key parameters that affect the control stability of the system, this paper proposes a novel global optimisation design method of key control parameters to reform the distribution of system eigenvalues and improve the stability of GCBPVS. Finally, case simulation and result analysis show that the accuracy of the above small-signal model is very high and the related stabilisation control method is very effective. In addition, hardware-in-the-loop (HIL) experiments demonstrate that the proposed control method has strong engineering practicability and is better suitable for application.