| 摘要 |
A circuit for converting an input voltage of variable frequency into an output voltage having a predetermined, lower frequency by means of a controlled static frequency converter which is operated as a direct link inverter. The output voltage of the frequency converter is multiplied in a first multiplier circuit by a sine voltage and in a parallel connected second multiplier circuit by a cosine voltage. The respective a-c components in each parallel circuit are filtered out in succeeding smoothing members. The remaining d-c voltage components are then each added in a summing point to preset reference values. The sum voltages are each fed to a voltage regulator, which is followed by a third and fourth multiplier, respectively. In the third and fourth multiplier the output of the voltage regulator is multiplied by the identical sine and cosine voltages. The last-mentioned multipliers are then connected to a common summing point which feeds a control voltage to the control unit of the frequency converter. |
