UNINTERRUPTABLE POWER SUPPLY WITH BALANCING BUCK/BOOST CONVERTER

摘要

A uninterruptable power supply system for supplying an electrical DC load with electric energy from an electrical network comprises an active rectifier connectable to the electrical network for rectifying an AC voltage into a DC voltage, a split DC link to be supplied from the active rectifier, the split DC link comprising two capacitors interconnected in series between a positive output and a negative output of the uninterruptable power supply system, wherein a DC link neutral point is provided between the two capacitors, and a balancing buck/boost converter connected in parallel to the split DC link between the positive output and the negative output and connected via an inductor to the DC link neutral point, such that the buck/boost converter is adapted to balance the two capacitors of the DC link, wherein an unbalance between the two capacitors is generated by one or more electrical DC loads connected between the positive output and the negative output, between the positive output and the DC link neutral point and/or between the negative output and the DC link neutral point.

主权项

1. An uninterruptable power supply system for supplying an electrical DC load with electric energy from an electrical network, the electrical network having an accessible network neutral point and at least one phase conductor, the uninterruptable power supply system comprising:
an active rectifier connectable to the electrical network via a line inductor for rectifying an AC voltage into a regulated DC voltage; a split DC link to be supplied from the active rectifier, the split DC link comprising two capacitors interconnected in series between a positive output and a negative output of the uninterruptable power supply system, wherein a DC link neutral point is provided between the two capacitors and the DC link neutral point as well as at least one of the positive output or negative output are accessible in order to be connected to the DC load, were the DC link neutral point is connected to the network neutral point during operation; a balancing buck/boost converter connected in parallel to the split DC link between the positive output and the negative output and connected via an inductor of the balancing buck/boost converter to the DC link neutral point, such that the buck/boost converter is adapted to balance the two capacitors is generated by one or more electrical DC loads connected between the DC link neutral point and at least one of the positive or negative output; and an electric energy storage to be charged by the DC link and for supplying the DC link with electric energy, when the electrical network has a power failure.