Method for controlling a converter having controllable power semiconductors, in which - state current values x̂ ( k) and state intermediate circuit energy values are combined in a state vector describing the state of the converter, current setpoint values and intermediate circuit energy setpoint values are combined in a setpoint vector, the state vector and the setpoint vector are compared to obtain control difference values, - the control difference values are fed to a control unit (14, 16), which generates such actuating voltage values u ( k) at its output that the control difference values become as small as possible, - control electronics provide control signals depending on the actuating voltage values u ( k) and transmit them to the power semiconductors (S1, S2) of the converter, wherein - the state current values x̂ ( k) are calculated from measured current values by an observation unit proceeding from the actuating voltage values u ( k), wherein the observation unit models the converter and takes delay effects into account so that the state current values x̂ ( k) correspond to the instantaneous measured current values freed of delay effects, and wherein - the 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)) by 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 - in addition to the state current values x̂ ( k), the state intermediate circuit energy values ( ŵ ( k)) are fed to the control unit (14, 16). - state current values x̂ ( k) and state intermediate circuit energy values are combined in a state vector describing the state of the converter, current setpoint values and intermediate circuit energy setpoint values are combined in a setpoint vector, the state vector and the setpoint vector are compared to obtain control difference values, - the control difference values are fed to a control unit (14, 16), which generates such actuating voltage values u ( k) at its output that the control difference values become as small as possible, - control electronics provide control signals depending on the actuating voltage values u ( k) and transmit them to the power semiconductors (S1, S2) of the converter, wherein - the state current values x̂ ( k) are calculated from measured current values by an observation unit proceeding from the actuating voltage values u ( k), wherein the observation unit models the converter and takes delay effects into account so that the state current values x̂ ( k) correspond to the instantaneous measured current values freed of delay effects, and wherein - the 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)) by 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 - in addition to the state current values x̂ ( k), the state intermediate circuit energy values ( ŵ ( k)) are fed to the control unit (14, 16). - the state current values x̂ ( k) are calculated from measured current values by an observation unit proceeding from the actuating voltage values u ( k), wherein the observation unit models the converter and takes delay effects into account so that the state current values x̂ ( k) correspond to the instantaneous measured current values freed of delay effects, and wherein - the 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)) by 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 - in addition to the state current values x̂ ( k), the state intermediate circuit energy values ( ŵ ( k)) are fed to the control unit (14, 16).