Patent ID: 8310794
Filing Date: 2012-11-13
Classification: H02J,H02M

Abstract:
1. An electric power supply apparatus of an electric motor of a ship, the apparatus comprising an AC/DC converter and a DC/AC converter, the DC sides of the converters being interconnected and the alternating current side of the DC/AC converter being controllable for forming a desired alternating current, wherein the apparatus comprises a monitoring apparatus for monitoring the frequency of the alternating current side of the AC/DC converter, comparison means for comparing the frequency monitored by the monitoring apparatus with a reference frequency, compensation means for forming a compensation control signal as a response to the comparison of the comparison means and control signal means for forming a control signal for the alternating current side of the DC/AC converter from an external setting signal and the compensation control signal, the formed control signal being to change input of electric energy to the electric motor and thereby being to change energy demand of an electric network, in such a way that subtraction of the compensation control signal from the external setting signal the input of electric energy to the electric motor is reduced, and addition of the compensation control signal to the external setting signal the input of electric energy to the electric motor is increased.