energy that is not needed initially is stored in the energy storage device 9 so as to be available to the inverter 4 during peak loads in this manner peak loads are absorbed by the energy management system 7 rather than imposed on the direct current voltage link circuit 12 the energy storage device 9 is constructed in accordance with the following aspects starting at the acceptable input voltage region u pwr of the inverter 4 the energy storage device 9 must be charged to the maximum acceptable voltage by the energy management system 7 at the beginning of the operation of the motor 2 the energy storage device 9 must be dimensioned in such a way that once periodic peak powers have ended the voltage at the energy storage device 9 does not fall below the lower voltage limit of the inverter 4 during periods of low loads or recovery for example during braking of the electric motor 2 the energy management system 7 causes the energy storage device 9 to be charged with a constant power this recharge current is ideally optimized in terms of the periodic peak loads of the drive motor 2 so that when the maximum charged voltage is attained in the energy storage device 9 the next acceleration of the electric motor 2 occurs fig3 a shows an electronic control unit 8 in connection with an energy storage device 9 which are constructed to even out motor operation peak loads of an electric motor 2 however the circuit as shown in fig3 a does not allow energy recovery so that it can only be used to compensate for motor operation peak loads in this case an inverter 4 allowing only motor operation is connected to the energy storage device 9.