Procedure and apparatus for uninterruptible power supply
First Claim
1. A procedure for an operation of uninteruptible power supply supplying power over an uninterruptible bus to an a.c. load, said a.c. load being connectable to an a.c. power supply network by means of an inductive arrangement having a variable effective impedance and a switch in series with said inductive arrangement, the procedure comprising the steps of:
- varying the effective impedance to a low value, closing said switch, and maintaining an energy storage unit at a fully charged level by a static converter arrangement connected to said storage unit, when said network status is changed to normal, andvarying the effective impedance to a high value, opening said switch, and supplying power to said a.c. load from said storage unit by means of said static converter arrangement when said network status is changed to malfunctioning.
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Accused Products
Abstract
To supply various loads connected to a uninterruptible bus, a power supply system N is connected (when functioning normally) by means of a mechanical switch, keeping an energy storage unit charged by means of a static converter which also functions preferrably as a phase shifter to stabilize the supply voltage. In the event of a power system malfunction, the storage unit is discharged by means of the static converter arrangement, and the mechanical switch is opened. The opening of this switch is not critical since between the switch and uninterruptible bus there is an inductance arrangement and an auxiliary switch. In case of a power system malfunction (auxiliary switch open), a large inductance and its large corresponding impedance of the inductive impedance arrangement becomes effective which during proper operation of the power system is shunted. Thus, during proper operation of the system only low inductive impedances (11, 12) and their correspondingly low impedances are effective via which a high current can flow from power supply system N, which suffices to trigger the load unit fuses in the event of a load unit short-circuit thus allowing such loads to self disconnect and not interrupt the bus by dragging it down with a heavy current malfunction.
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Citations
11 Claims
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1. A procedure for an operation of uninteruptible power supply supplying power over an uninterruptible bus to an a.c. load, said a.c. load being connectable to an a.c. power supply network by means of an inductive arrangement having a variable effective impedance and a switch in series with said inductive arrangement, the procedure comprising the steps of:
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varying the effective impedance to a low value, closing said switch, and maintaining an energy storage unit at a fully charged level by a static converter arrangement connected to said storage unit, when said network status is changed to normal, and varying the effective impedance to a high value, opening said switch, and supplying power to said a.c. load from said storage unit by means of said static converter arrangement when said network status is changed to malfunctioning. - View Dependent Claims (2, 3)
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4. An apparatus for an uninterruptible power supply of load units comprising:
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a switch connected between an a.c. power supply network and an uninterruptible bus connected to at least one load unit; a monitoring device monitoring an a.c. power supply network status, either normal or malfunctioning, of said a.c. power supply network and an energy storage unit status, either of a completely charged or not completely charged status of an energy storage unit; said energy storage unit is connected by means of said static converter to said uninterruptible bus; said monitoring device keeps said switch closed as long as said power network status is normal and controls said static converter in such a fashion that said energy storage unit is held at a nearly constant charge level, and said monitoring device opens said switch in said event said power system status changes to malfunctioning and regulates said static converter to provide an adequate supply voltage at said uninterruptible bus; said monitoring device reverses a controllable switching mechanism when said power network status changes to malfunctioning; and an inductive impedance arrangement is provided between said switch and said uninterruptible bus having an inductive impedance level effective on a current flowing between said power supply network and said uninterruptible bus, which is varied by said switching mechanism. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11)
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Specification