A controller 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 (SW) 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 (SW) 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. <EOS>