In order to improve the output power quality of the inverter

a kind of two-degree-of-freedom control strategy based on a resonant tracking controller and an improved uncertainty and disturbance estimator is designed.The tracking control and disturbance suppression control in the new controller are decoupled and relatively independent of each other.A time-delay action is introduced into the disturbance observer to minimize the amplitude of the output impedance at odd harmonics.With proper disturbance suppression

the tracking resonant controller can achieve that the output of the nominal system follows a sinusoidal benchmark reference with near-zero amplitude and phase error.The three-phase inverter experimental platform is used to perform tests with linear and nonlinear loads.The experimental results verify that the proposed control strategy can effectively improve the output power quality of the inverter.