The microgrid inverter system is characterized by nonlinearity

strong coupling

violent disturbance and flexible switching mode. It is not easy to meet requirements through conventional dual loop control. As for the active disturbance rejection control(ADRC)

all uncertainties of the system are regarded as total disturbances

which will be estimated and compensated dynamically. As a result

the complex system can be corrected to integral series type to achieve expected control performance. With the adoption of linear active disturbance rejection control(LADRC)technology with more engineering application value

this paper designs a second-order LADRC controller which takes the output voltage and its differential as state variables. Considering that the extended state observer(ESO)is the core of LADRC

the output voltage error derivative term is introduced to improve the observation capability of ESO. Further

a first-order inertial link is embedded into the total perturbation channel to avoid increasing observation noise. Frequency response characteristics of LADRC and typical dual loop control system show that the improved LADRC has a better disturbance rejection performance than the other two. Simulation and experimental results further prove the effectiveness of the proposed strategy.