US 5,686,768 AGranted

Emergency power system

AssigneeSilicon Power Electronics A/S

InventorsOve Lyck Thomsen, Henning Roar Nielsen, S.o slashed.ren Henrik Nielsen Rathmann

Life of this patent

Estimating the term…

Loading patent…

Abstract

An emergency power system is connected between an AC voltage source and a load. The emergency power system ensures a stable voltage on the output, even if the AC voltage received from the AC voltage source is irregular or is interrupted briefly. The emergency power system includes an AC/DC converter coupled between the load terminals and an AC regulator positioned between the AC voltage source and the load. The AC/DC converter is coupled to a chargeable battery and serves as a charging rectifier for the battery in normal operation and as an inverter in emergency operation, the battery voltage being converted to AC voltage on the output of the emergency power system. The AC regulator is built as a controllable current generator supplying on its output an AC current which is in phase with the AC voltage received from the AC voltage source. Irrespective of the energy direction through it, the AC/DC converter maintains the predetermined AC voltage (V.sub.OUT) across the output terminals of the emergency power system. The system includes a comparator which senses and compares the battery state to a predetermined reference and supplies a signal in response to this. The intensity of the current supplied by the AC regulator is controlled in response to the signal generated by the comparator so that in terms of energy the system is in power balance.

Claims8

Dependent claims

An emergency power system for connection between a pair of input terminals for an AC voltage source and a pair of output terminals for a load, said emergency power system ensuring a stable voltage across the pair of output terminals even if the AC voltage received from the AC voltage source is irregular or is briefly interrupted, said emergency power system comprising:

an AC regulator coupled between said input terminals and said output terminals, said AC regulator including a controllable current generator for supplying on its output an AC current which is in-phase with the voltage received from the AC voltage source;
a chargeable battery;
an AC/DC converter coupled to the output of the controllable current generator, to the pair of output terminals, and to the chargeable battery, for serving as a charging rectifier for the battery in normal operation and as an inverter for converting the battery voltage to an AC voltage when said AC source is irregular or interrupted,
a control circuit coupled to said pair of output terminals and to said AC/DC converter, for controlling said AC/DC converter to maintain a predetermined AC voltage across said pair of output terminals;
and
a comparator coupled to said battery and to said AC regulator, for sensing the battery voltage and comparing it with a reference voltage, and for providing a control signal for controlling the intensity of the current supplied by said controllable current generator.

3 more elements

Dependencies are inferred from the claim text.