Adaptive sliding-mode voltage control for inverter operating in islanded mode in microgrid

• A sliding-mode voltage controller is applied to islanded parallel inverters.
• An adaptive algorithm to observe the value of filter parameters can guarantee the robustness of control system of inverter.
• An adaptive algorithm of switching gain can eliminate reaching phase and reduce chattering of output voltage of inverter.
• The proposed ASMC can guarantee global robustness and enhance the performance of perturbation rejection.

Harmonic current caused by nonlinear loads and parametric variations of output filter of inverters make popular proportional–integral–derivative (PID) voltage controller far beyond excellent performance in case of microgrid operating in islanded mode. Motivated by this limitation, this paper proposes an adaptive sliding-mode controller (ASMC) to enhance disturbance-rejection performance of control system of islanded parallel inverters. And adaptive algorithms are designed to observe external disturbances and internal perturbation so as to guarantee the globe robustness of control system of inverter. The switching gain of control input is designed to be a time-varying value which effectively reduces undesirable chattering of control input signal. Simulating and experimental results are presented that the total harmonic distortion, chattering, and steady-state error of output voltage of islanded parallel inverters are effectively reduced and the dynamic performances and the capability of perturbation rejection of control system of inverter are effectively enhanced.