Method and device in frequency converter
View Patent ↗A method in connection with a frequency converter for correcting the power factor of the frequency converter, and a power factor correction unit. The method includes connecting the power factor correction unit between a rectifier bridge of the frequency converter and the supplying AC voltage network, generating with the power factor correction unit DC voltage from the AC voltage of the supply network and feeding the generated DC voltage to the frequency converter via the rectifier bridge of the frequency converter.
1. A method in connection with a frequency converter for correcting the power factor of the frequency converter the method comprising:
connecting a power factor correction unit between a rectifier bridge of the frequency converter and the supplying AC voltage network,
generating DC voltage with the power factor correction unit from the AC voltage of the supplying network,
feeding the generated DC voltage to the frequency converter via the rectifier bridge of the frequency converter.
2. The method of claim 1 , wherein generation of DC voltage by the power factor correction unit also comprises a step of raising the magnitude of DC voltage with respect to the magnitude of the rectified network voltage.
3. The method of claim 1 , wherein generation of DC voltage by the power factor correction unit comprises steps of
performing measurements of one or more voltages or currents in the power factor correction unit and
controlling one or more controllable switch components of the power factor correction circuit included in the power factor correction unit on the basis of the measurements performed in the power factor correction unit.
4. A power factor correction unit for a frequency converter, comprising input connectors for connecting to AC voltage supply,
one or more current and/or voltage measurements, which are arranged to measure internal quantities of the power factor correction unit,
output connectors for connecting the power factor correction unit to the rectifier bridge of the frequency converter,
a power factor correction circuit, which is arranged to perform a power factor correction on the basis of the internal measurements of the power factor correction unit and to generate for its output connectors a DC voltage that is arranged for supply to the rectifier bridge of the frequency converter.
5. The method of claim 2 , wherein generation of DC voltage by the power factor correction unit comprises steps of
performing measurements of one or more voltages or currents in the power factor correction unit and
controlling one or more controllable switch components of the power factor correction circuit included in the power factor correction unit on the basis of the measurements performed in the power factor correction unit.