Abstract: In order to improve the inertia support ability of grid-connected converter of new energy based on

DC capacitor energy virtual inertia control to the power system，an adaptive virtual inertia control method based on

linear quadratic regulator（LQR）was proposed. On the basis of analyzing the dynamic characteristics of the virtual

synchronous generator（VSG），the mathematical relationship between the inertia parameters and the system

frequency response characteristics was obtained，and an adaptive inertia control model based on LQR was

established. The optimal feedback matrix was found by LQR cost function to make the state variables approach

zero quickly and meet the control requirements with the least input energy. The simulation results show that the

method can make the new energy grid-connected converter optimize the allocation of limited DC capacitance

energy according to the system frequency fluctuation，quickly damp the frequency change，improve the system

frequency response characteristics，enhance the inertia support ability of the new energy grid-connected converter

to the power system，and ensure the stability of the power system.

      Key words: new energy；grid-connected converter；linear quadratic regulator（LQR）；virtual inertia