Modular uninterruptible power supply battery management

• US 6,700,351 B2
• Filed: 02/20/2001
• Issued: 03/02/2004
• Est. Priority Date: 02/18/2000
• Status: Expired due to Term

• Current Assignee: Vertiv Corporation (Vertiv Holdings Co.)
• Original Assignee: Liebert Corporation (Vertiv Holdings Co.)
• Inventors: Crawford, Christopher, Weber, Dennis, Reinbolt, Brad, Gabel, Mark, Blair, Charles F., Birchmeier, John R.
• Primary Examiner(s): Tso, Edward H.
• Application Number:
  US09/789,099
• Publication Number:
  US 20010033502A1
• Time in Patent Office: 1,106 Days
• Field of Search: 320/106, 320/110, 320/112, 320/116, 320/125, 320/128, 320/132, 320/134, 320/135, 320/136
• US Class Current: 320/125
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0029 with safety or protection devices or circuits
• CPC Class Codes: H02J 7/00304 Overcurrent protection
• CPC Class Codes: H02J 7/00309 Overheat or overtemperature protection
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/0049 Detection of fully charged condition
• CPC Class Codes: H02J 7/005 Detection of state of health [SOH]
• CPC Class Codes: H02J 9/062 for AC powered loads

Abstract

A modular uninterruptible power supply is disclosed, which provides complete redundancy for all components required for UPS operation. Novel aspects of the invention include design of the modules and their interconnection and interoperability, as well as improved operation techniques applicable to UPS systems generally.

Claims

1. An intelligent battery module comprising at least one battery string, a fuse, and a relay, all connected in series, the battery module further comprising a microprocessor based controller for monitoring and controlling the battery module components.

2. The intelligent battery module of claim 1 wherein the microprocessor monitors the charge status of the battery strings.

3. The intelligent battery module of claim 1 wherein the microprocessor controls the relay to disconnect the battery strings from a UPS bus when a failure of the battery strings is detected.

4. A method of battery module status monitoring comprising:

setting an empirical energy rating to an initial value corresponding to a manufacturer'"'"'s rating of the battery module;

setting a present energy value equal to 0.9 times the initial empirical energy rating;

determining the deliverable energy of the battery by multiplying the initial present energy by a temperature derating factor and a load derating factor;

updating the present energy value to account for charging or discharging of the battery;

updating the deliverable energy to account for temperature or load changes;

updating the empirical energy rating at the end of a substantially full discharge cycle to equal the sum of the total energy delivered by the battery during the discharge cycle and the present energy value at the end of the discharge cycle.

5. A method of determining the battery run time of a UPS comprising a plurality of battery modules comprising the steps of:

determining the present energy stored in each battery module;

determining the deliverable energy stored in each battery module by multiplying the present energy of each battery module by a temperature derating factor and a load derating factor;

determining the run time of the UPS by adding the deliverable energy of each battery module and dividing by the total load on the UPS.

6. A method of determining the state of charge of a plurality of battery modules in a UPS comprising the steps of:

determining an empirical energy rating for each battery module;

determining the present energy stored in each battery module;

determining the state of charge of the battery modules by adding the present energy of each battery module and dividing by the sum of the empirical energy rating for each battery module.

7. A method of adjusting the state of charge of a battery module in a UPS, the method comprising:

periodically receiving time and date stamps from a control module;

storing the time and date stamps in a battery module controller memory when the battery module is removed from the UPS;

computing a time the battery module has been removed from the UPS when the battery module is re-inserted; and

adjusting the battery'"'"'s capacity information to account for charge capacity lost during the time the battery module was removed from the UPS.

8. A method of adjusting the state of charge of a battery module in a UPS, the method comprising:

periodically receiving time and date stamps from a control module;

storing the time and date stamps in a battery module controller memory when the UPS is turned off;

computing a time the UPS has been turned off when the UPS is turned back on; and

adjusting the battery'"'"'s capacity information to account for charge capacity lost during the time the battery module was removed from the UPS.