Two-level protection for uninterrupted power supply
First Claim
Patent Images
1. A method for responding to electrical power source irregularities in an uninterruptible power supply system utilizing a rechargeable DC power supply as back up power, comprising:
- providing an uninterruptible power supply system comprising a three phase AC source converter connectable to a three phase AC power source and a three phase AC load converter connectable to a three phase load, wherein the converters are interconnected by a DC bus;
monitoring DC bus voltage on the DC bus;
establishing a first DC bus voltage threshold indicative of a first power source irregularity and a second DC bus voltage threshold indicative of a second and distinct power source irregularity, wherein the first threshold is greater than the second threshold;
comparing the DC bus voltage to the first and second thresholds;
commuting electrical power from both the power source and from the DC power supply to the DC bus when the DC bus voltage is intermediate the first and second thresholds; and
, conversely commuting electrical power only from the DC power supply to the DC bus when the DC bus voltage is less than the second threshold, and disabling the source converter.
3 Assignments
0 Petitions
Accused Products
Abstract
Method and apparatus for determining transient power source defects versus nontransient, grid failures result in power being selectively applied to a DC bus for application to a load by either the power source, a rechargeable DC power supply, or both. The severity of the power interruption determines the degree to which the power will be supplied to a load through a power converter assembly by either an AC source or a rechargeable DC power supply.
70 Citations
25 Claims
-
1. A method for responding to electrical power source irregularities in an uninterruptible power supply system utilizing a rechargeable DC power supply as back up power, comprising:
-
providing an uninterruptible power supply system comprising a three phase AC source converter connectable to a three phase AC power source and a three phase AC load converter connectable to a three phase load, wherein the converters are interconnected by a DC bus;
monitoring DC bus voltage on the DC bus;
establishing a first DC bus voltage threshold indicative of a first power source irregularity and a second DC bus voltage threshold indicative of a second and distinct power source irregularity, wherein the first threshold is greater than the second threshold;
comparing the DC bus voltage to the first and second thresholds;
commuting electrical power from both the power source and from the DC power supply to the DC bus when the DC bus voltage is intermediate the first and second thresholds; and
,conversely commuting electrical power only from the DC power supply to the DC bus when the DC bus voltage is less than the second threshold, and disabling the source converter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. An apparatus for responding to electrical power source irregularities in an uninterruptible power supply system comprising a rechargeable DC power supply interconnected to a DC bus, comprising:
-
an uninterruptible power supply system comprising a three phase AC source converter connectable to a three phase AC power source and a three phase AC load converter connectable to a three phase load, wherein the converters are interconnected by a DC bus;
means for monitoring DC bus voltage on the DC bus;
establishing means for establishing a first DC bus voltage threshold indicative of a first power source irregularity and a second DC bus voltage threshold indicative of a second and distinct power source irregularity, wherein the first threshold is greater than the second threshold;
comparing means for comparing the DC bus voltage to the first and second thresholds; and
commuting means for commuting electrical power from both the power source and from the DC power supply to the DC bus when the DC bus voltage is intermediate the first and second thresholds, and for conversely commuting electrical power only from the DC power supply to the DC bus when the DC bus voltage is less than the second threshold and for disabling the source converter. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
-
-
19. A method for responding to electrical power source irregularities in an uninterruptible power supply system, comprising:
-
providing an uninterruptible power supply system comprising an AC source converter connectable to an AC power source and an AC load converter connectable to a load, wherein the converters are interconnected by a DC bus;
interconnecting a rechargeable DC power supply to the DC bus;
monitoring DC bus voltage on the DC bus;
establishing a first DC bus voltage threshold indicative of a first power source irregularity and a second DC bus voltage threshold indicative of a second and distinct power source irregularity, wherein the first threshold is greater than the second threshold;
comparing the DC bus voltage to the first and second thresholds;
commuting electrical power from both the power source and from the DC power supply to the DC bus when the DC bus voltage is intermediate the first and second thresholds; and
,conversely commuting electrical power only from the DC power supply to the DC bus when the DC bus voltage is less than the second threshold, and disabling the source converter. - View Dependent Claims (20)
-
-
21. An apparatus for responding to electrical power source irregularities in an uninterruptible power supply system comprising a rechargeable DC power supply interconnected to a DC bus, comprising:
-
an uninterruptible power supply system comprising a three phase AC source converter connectable to a three phase AC power source and a three phase AC load converter connectable to a three phase load, wherein the converters are interconnected by a DC bus;
a number of voltage sensors coupled to sense DC bus voltage on the DC bus;
a controller configured to compare the DC bus voltage to a first DC bus voltage threshold indicative of a first power source irregularity and a second DC bus voltage threshold indicative of a second and distinct power source irregularity, wherein the first threshold is greater than the second threshold; and
further configured to provide control signals to at least one of the three phase AC source converter and the three phase AC load converter to commutate electrical power from both the power source and from the DC power supply to the DC bus when the DC bus voltage is intermediate the first and second thresholds, and for conversely commuting electrical power only from the DC power supply to the DC bus when the DC bus voltage is less than the second threshold and for disabling the source converter. - View Dependent Claims (22, 23, 24, 25)
-
Specification