A method for operating an inverter which is connected to an energy supply grid via a transformer for feeding in electrical energy into the energy supply grid, includes measuring output currents and output voltages of the inverter, and actuating power switches of the inverter using actuation signals that are generated as a function of the measured output currents and the measured output voltages at a fundamental frequency of the energy supply grid. The actuation signals are further generated as a function of a harmonic component of the measured output voltages of the inverter at a multiple of the fundamental frequency using a control loop with positive feedback.