In order to reduce the switching frequencies of power semiconductors, synchronous optimal pulse width modulation provides an appropriate solution. The switching angles result from complex offline calculations, assuming steady-state operation. Medium voltage drives when applied to the retrofit of existing fixed speed induction motors often include an output LC-filter which introduces a resonant circuit. Therefore, only in steady-state operations the combination of a high-power drive with a LC-filter and optimized pulse width modulation delivers satisfactory behavior. Changes in operating conditions cause weakly damped electrical oscillations, which can be described as dynamic modulation errors. In this paper, a novel energy-based control method is proposed, in order to damp the LC-filter excitation without increasing the switching frequency. The introduced control technique has been verified by simulations of a 2.4 kV induction motor drive.