Virtual synchronous control based on DC-link dynamics for PV inverter in weak gird

The high penetration of grid-connected photovoltaic (PV) inverter into power grid results in difficulties to guaranty the generator-load power balancing. That is due to the intermittence of solar energy and non-dispatchability nature of PV generators. Therefore, to enhance generator-load power balancing, this paper proposes a control method allowing the single-stage PV inverters to autonomously dispatch the generated power for the frequency change compensation. To achieve that, a single inverter in the system estimates the available power by generating the reference DC-link voltage corresponding to the maximum power; whereas other inverters in the system dispatch the available power by drooping DC-link voltage with respect to the change in system frequency. The simulations are performed by means of PLECS simulation software. The results confirm the effectiveness of the proposed power dispatching control method, where the power dispatching by single-stage PV inverter is achieved under several operating conditions of grid frequency change.