Maximized battery run-time in a parallel UPS system
First Claim
1. A method of controlling a plurality of battery voltages in a plurality of uninterruptible power supply (UPS) modules, each of the UPS modules having an inverter for providing power to a load, each of the inverters receiving power from a battery, the method comprising:
- determining an average voltage of the batteries from at least two of the UPS modules;
comparing the battery voltage from the at least two UPS modules to the average battery voltage; and
generating a control signal responsive to the comparison that causes the inverters to adjust the amount of power delivered by the batteries to the load, the control signal intentionally causing an imbalance by intentionally increasing the amount of power delivered from at least one of the batteries who'"'"'s voltage is greater than the average battery voltage and intentionally decreasing the amount of power delivered from at least one of the batteries who'"'"'s voltage is less than the average battery voltage, wherein intentionally causing an imbalance comprises intentionally placing one or more of the inverters in an overload condition.
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Abstract
An uninterruptible power supply (UPS) includes a plurality of UPS modules. Each of the UPS modules has a battery that provides power to a protected load in the event of a utility power failure. A plurality of controllers control how much power each of the batteries deliver to the protected load, and a communication bus allows the controllers to exchange information about the battery voltages. One of the controllers calculates the average battery voltage of the plurality of batteries and adjusts the amount of energy provided by an individual battery such that the battery voltage is about equal to the average battery voltage.
41 Citations
13 Claims
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1. A method of controlling a plurality of battery voltages in a plurality of uninterruptible power supply (UPS) modules, each of the UPS modules having an inverter for providing power to a load, each of the inverters receiving power from a battery, the method comprising:
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determining an average voltage of the batteries from at least two of the UPS modules; comparing the battery voltage from the at least two UPS modules to the average battery voltage; and generating a control signal responsive to the comparison that causes the inverters to adjust the amount of power delivered by the batteries to the load, the control signal intentionally causing an imbalance by intentionally increasing the amount of power delivered from at least one of the batteries who'"'"'s voltage is greater than the average battery voltage and intentionally decreasing the amount of power delivered from at least one of the batteries who'"'"'s voltage is less than the average battery voltage, wherein intentionally causing an imbalance comprises intentionally placing one or more of the inverters in an overload condition. - View Dependent Claims (5, 6, 7, 8, 9)
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2. An uninterruptible power supply (UPS) system comprising:
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a plurality of UPS modules, each of the UPS modules including a battery that provides power to a protected load during a utility power failure; a plurality of controllers that control how much power each of the batteries deliver to the protected load; a communication bus that allows the controllers to exchange information about the battery voltages; wherein at least one of the controllers calculates an average battery voltage of the plurality of batteries and adjusts the amount of energy provided by at least one of the batteries, and wherein the at least one controller outputs a control signal intentionally causing an imbalance by intentionally increasing the amount of power delivered from at least one of the batteries who'"'"'s voltage is greater than the average battery voltage and intentionally decreasing the amount of power delivered from at least one of the batteries who'"'"'s voltage is less than the average battery voltage, wherein intentionally causing an imbalance comprises intentionally placing one or more of the inverters in an overload condition. - View Dependent Claims (3, 4)
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10. A method of controlling a plurality of battery voltages in a plurality of uninterruptible power supply (UPS) modules, each of the UPS modules having an inverter for providing power to a load, each of the inverters receiving power from a battery, the method comprising:
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generating a control signal that intentionally reduces an amount of energy supplied through one or more of the inverters to zero, wherein the control signal also intentionally places one or more of the inverters in an overload condition; estimating a runtime of at least one of the batteries; and balancing the estimated battery runtime against an overload runtime of the inverter intentionally place in the overload condition. - View Dependent Claims (11, 12)
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13. A method of controlling a plurality of battery voltages in a plurality of uninterruptible power supply (UPS) modules, each of the UPS modules having an inverter for providing power to a load, each of the inverters receiving power from a battery, the method comprising:
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generating a control signal that intentionally places one or more of the inverters in an overload condition; estimating a runtime of at least one of the batteries; and balancing the estimated battery runtime against an overload runtime of the inverter intentionally place in the overload condition.
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Specification