Spare bus power plant

• US 6,630,750 B2
• Filed: 12/15/2000
• Issued: 10/07/2003
• Est. Priority Date: 12/16/1999
• Status: Expired due to Fees

• Current Assignee: Jomahip, LLC
• Original Assignee: Jomahip, LLC
• Inventors: McAndrews, Joseph M.
• Primary Examiner(s): Sircus, Brian
• Assistant Examiner(s): RIOS CUEVAS, ROBERTO JOSE
• Application Number:
  US09/738,008
• Publication Number:
  US 20010024065A1
• Time in Patent Office: 1,026 Days
• Field of Search: 307/64, 307/66, 307/65, 363/44, 363/67, 363/69, 363/72
• US Class Current: 307/64
• CPC Class Codes: H02J 1/10 Parallel operation of dc sources
• CPC Class Codes: H02J 9/061 for DC powered loads

Abstract

A DC power plant system is provided utilizing battery back up for emergency power for use with telephone switching equipment or other loads, whereby the system provides for a more efficient use of the DC rectifiers and allows a standby emergency power source to be sized to fit only the actual load rectifiers which will reduce the cost of the emergency standby power system.

Claims

1. A system for supplying uninterrupted DC power to a load to which DC power normally is derived from an AC power source or from an emergency AC power source and a plurality of DC batteries are provided to deliver the DC power to the load when AC power fails to be available, comprising:

a load bus;

a bank of load rectifiers connected to said load bus, responsive to AC power from said AC power sources to respectively produce DC power for delivery along said load bus to the load;

a spare bus;

a bank of spare rectifiers connected to said spare bus, responsive to said AC power sources to respectively produce DC power for delivery along said spare bus;

a blocking circuit coupling said spare bus to said load bus so as to enable current to flow from a said spare rectifier through said blocking circuit when the magnitude of the DC voltage on the load bus drops a predetermined amount below that on the spare bus; and

a controller coupled to sense the voltage on the load bus and from said AC power sources to produce a control signal to enable a spare rectifier upon a failure of a said load rectifier.

2. The system of claim 1 where said blocking circuit comprises:

a diode, wherein;

the anode is connected to the load bus and the cathode connected to the spare bus so that the diode will not conduct until the differential voltage developed on the load bus and spare bus rises above the forward bias voltage of said diode;

a relay, wherein;

the normally closed contacts of said relay are connected in parallel with said diode, and

the coil of said relay is connected to said controller to receive a control signal so that upon conduction of the diode, said controller sends a control signal to energize the relay in said blocking circuit which will directly connect the load bus to the spare bus.

3. The system of claim 2 wherein the voltage of the spare bus is offset a fraction of a volt from the load bus voltage so that upon a failure of the relay in said blocking circuit, the controller alerts the user to a relay failure.

4. The system of claim 1 wherein said controller is connected to each spare rectifier wherein a control signal is utilized to adjust the output voltage of each spare rectifier upon a load rectifier failure.

5. The system of claim 4 wherein the controller sequentially adjusts the voltage of a spare rectifier to the desired load bus voltage level in response to a load rectifier failure.

6. The system of claim 1 wherein the controller stores information in memory regarding a rectifier failure.

7. The system of claim 1 wherein the controller stores information in memory regarding the total number of rectifier failures.

8. A system for supplying uninterrupted DC power to a load to which DC power normally is derived from an AC power source or from an emergency AC power source and a plurality of DC batteries are provided to deliver the DC power to the load when AC power fails to be available, comprising:

a load bus;

a bank of load rectifiers connected to said load bus, responsive to AC power from said AC power sources to respectively produce DC power for delivery along said load bus to the load;

a bank of spare rectifiers connected to said load bus, responsive to said AC power sources to respectively produce DC power for delivery along said spare bus;

a reference voltage control circuit coupling said load bus to a reference voltage input of a spare rectifier so as to connect said load bus to said reference voltage input when the magnitude of the DC voltage on the load bus drops a predetermined level; and

a controller coupled to sense the voltage on the load bus and from said AC power sources to produce a control signal to enable a spare rectifier upon a failure of a said load rectifier.

9. The system of claim 8 where said reference voltage control circuit comprises:

a diode, a resistor and a first relay and a second relay for each spare rectifier wherein;

the anode of said diode is connected to the reference voltage input of said spare rectifier and the cathode is connected to the resistor so that the diode will not conduct until the voltage developed across the diode rises above the forward bias voltage of said diode;

the normally closed contacts of the first relay are connected in parallel with said diode and the normally closed contacts of the second relay are connected in parallel with said resistor;

the resistor is connected to the cathode of said diode and to the load bus.

10. The system of claim 9 wherein said controller is connected to each the first and the second relay wherein a control signal is utilized to adjust the output voltage of each spare rectifier upon a load rectifier failure.

11. The system of claim 8 wherein the controller sequentially adjusts the voltage of the spare rectifiers to the desired load bus voltage level in response to a load rectifier failure.

12. The system of claim 8 wherein the controller stores information in memory regarding a rectifier failure.

13. The system of claim 8 wherein the controller stores information in memory regarding the total number of rectifier failures.

14. A method for supplying uninterrupted DC power to a load along a load bus to which DC power normally is derived from an AC power source or from an emergency AC power source and a plurality of DC batteries are provided to deliver the DC power to the load when AC power fails to be available comprising the steps of:

providing a bank of rectifiers and segregating the rectifiers into load and spare rectifiers with the load rectifiers connected to the load bus to provide DC power thereto at a desired DC output voltage;

providing a spare bus to which the spare rectifiers are connected and with the spare bus selectively connected to the load bus to provide spare DC power thereto from the spare rectifiers;

adjusting the output voltages of the spare rectifiers so that selected ones are effectively taken off line and at least one of said spare rectifiers has an output voltage that is at a predetermined minimum voltage level for the load bus;

monitoring the load bus so as to detect when a load rectifier has failed;

adjusting the voltage level of the spare rectifiers in accordance with failed load rectifiers to enable a spare rectifier to provide DC power to the load and effectively become a load rectifier.

15. The method of claim 14 further comprising the steps of:

coupling the spare bus to the load bus through a diode and adjusting the voltages on the spare rectifiers so as to assure that the diode is normally reverse biased and becomes forwardly biased when a load rectifier has failed.

16. The method of claim 14 further comprising the steps of:

connecting a controller to each spare rectifier; and

sending a control signal from said controller to adjust the output voltages of each spare rectifier in response to a load rectifier failure.

17. The method of claim 16 further comprising the step of sequentially adjusting output voltages of each spare rectifier in response to a load rectifier failure.