A controller (700, 800) for a grid-tied power converter, the converter comprising a switching rectifier connected to an inductor-capacitor-inductor, LCL, filter comprising, for each phase of the converter, a converter inductor connected to the switching rectifier, a capacitor, and a grid inductor connected to a voltage source through a source conductor with an unknown inductance, the controller comprising: an adaptive estimator, the adaptive estimator comprising a voltage input and a current input, the current input being from at least one converter inductor of a phase of the converter, the adaptive estimator comprising an ideal LCL filter model and a disturbance compensator, the ideal LCL filter model configured to generate, using a simple filter, a desired dynamic behavior of the converter and LCL filter, the adaptive estimator generating an output current; and an LCL steady-state, SS, compensation configured to model a steady-state effect of the LCL filter and source conductor; a selector switch for selecting one of an output current of the converter and the output current of the adaptive estimator as input to a feedback loop of the converter; a scalar link configured to adjust one or more compensation values of the disturbance compensator, wherein the one or more compensation values are related to compensation terms in the feedback loop of the converter; and a second LCL SS comp block configured to output a current to the feedback loop of the converter, wherein a reference current signal is fed into the second LCL SS comp block, wherein a disturbance output voltage of the adaptive estimator is subtracted from an output of the feedback loop of the converter to form a preliminary voltage control signal, wherein the preliminary voltage control signal is summed with an output of the LCL SS compensation to form a voltage control signal configured to control switching of the switching rectifier, and wherein the preliminary voltage control signal is the voltage input to the adaptive estimator. an adaptive estimator, the adaptive estimator comprising a voltage input and a current input, the current input being from at least one converter inductor of a phase of the converter, the adaptive estimator comprising an ideal LCL filter model and a disturbance compensator, the ideal LCL filter model configured to generate, using a simple filter, a desired dynamic behavior of the converter and LCL filter, the adaptive estimator generating an output current; and an LCL steady-state, SS, compensation configured to model a steady-state effect of the LCL filter and source conductor; a selector switch for selecting one of an output current of the converter and the output current of the adaptive estimator as input to a feedback loop of the converter; a scalar link configured to adjust one or more compensation values of the disturbance compensator, wherein the one or more compensation values are related to compensation terms in the feedback loop of the converter; and a second LCL SS comp block configured to output a current to the feedback loop of the converter, wherein a reference current signal is fed into the second LCL SS comp block, wherein a disturbance output voltage of the adaptive estimator is subtracted from an output of the feedback loop of the converter to form a preliminary voltage control signal, wherein the preliminary voltage control signal is summed with an output of the LCL SS compensation to form a voltage control signal configured to control switching of the switching rectifier, and wherein the preliminary voltage control signal is the voltage input to the adaptive estimator.