Method for controlling a converter having controllable power semiconductors, in which - actual state values x̂ ( k) describing the state of the converter are compared with desired state values x Soll ( k), with control difference values being obtained, - the control difference values are supplied to a control unit (14, 16) which generates actuating voltage values u ( k) at its output, and - control electronics provide control signals depending on the actuating voltage values u ( k) and transmit said control signals to the power semiconductors (S1, S2) of the converter, wherein the control unit (14, 16) generates actuating voltage values u ( k) such that the control difference values become as small as possible, wherein the actual state values x̂ ( k) are calculated by an observation unit proceeding from the actuating voltage values u ( k) and taking account of measured current values x ( k), wherein the observation unit takes account of disturbance effects, with the result that the actual state values x̂ ( k) correspond to undisturbed current measurement values which have been freed of disturbance effects, characterized in that - state intermediate circuit energy values ŵ ( k) are determined from measured intermediate circuit energy values by means of an estimator unit that has recourse to a signal model of the intermediate circuit energy values, wherein the estimator unit calculates the parameters of the signal model of the intermediate circuit energy values w ( k) whilst determining in each case a DC variable representing state intermediate circuit energy values ŵ ( k) of the positive-side and the negative-side three-phase voltage source of the converter, and - the state intermediate circuit energy values ŵ ( k) are supplied to the control unit in addition to the state current values x̂ ( k). - actual state values x̂ ( k) describing the state of the converter are compared with desired state values x Soll ( k), with control difference values being obtained, - the control difference values are supplied to a control unit (14, 16) which generates actuating voltage values u ( k) at its output, and - control electronics provide control signals depending on the actuating voltage values u ( k) and transmit said control signals to the power semiconductors (S1, S2) of the converter, wherein the control unit (14, 16) generates actuating voltage values u ( k) such that the control difference values become as small as possible, wherein the actual state values x̂ ( k) are calculated by an observation unit proceeding from the actuating voltage values u ( k) and taking account of measured current values x ( k), wherein the observation unit takes account of disturbance effects, with the result that the actual state values x̂ ( k) correspond to undisturbed current measurement values which have been freed of disturbance effects, - state intermediate circuit energy values ŵ ( k) are determined from measured intermediate circuit energy values by means of an estimator unit that has recourse to a signal model of the intermediate circuit energy values, wherein the estimator unit calculates the parameters of the signal model of the intermediate circuit energy values w ( k) whilst determining in each case a DC variable representing state intermediate circuit energy values ŵ ( k) of the positive-side and the negative-side three-phase voltage source of the converter, and - the state intermediate circuit energy values ŵ ( k) are supplied to the control unit in addition to the state current values x̂ ( k).