3-phase power factor corrected AC to DC filtered switching power supply

• US 8,159,802 B2
• Filed: 11/17/2008
• Issued: 04/17/2012
• Est. Priority Date: 11/17/2008
• Status: Expired due to Fees

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Tinsley, Carl T. III, Pepa, Elton
• Primary Examiner(s): Barnie, Rexford
• Assistant Examiner(s): Hoang, Ann
• Application Number:
  US12/272,263
• Publication Number:
  US 20100124083A1
• Time in Patent Office: 1,247 Days
• Field of Search: 361/93.8
• US Class Current: 361/93.8
• CPC Class Codes: H02M 1/007 Plural converter units in cascade push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826
• CPC Class Codes: H02M 1/4216 operating from a three-phase input voltage H02M1/4233 takes precedence
• CPC Class Codes: H02M 1/4258 using a single converter stage both for correction of AC input power factor and generation of a regulated and galvanically isolated DC output voltage H02M1/4241 takes precedence
• CPC Class Codes: H02M 1/44 Circuits or arrangements for compensating for electromagnetic interference in converters or inverters
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

This invention relates to a power supply apparatus and method for converting three-phase delta AC power to DC power using EMI filters and PFC circuits to maintain balanced AC current loading and reduce radiated and conducted emissions. Overcurrent and temperature protection are also provided in conjunction with a novel optocoupler latch circuit for improving maintenance of the power supply.

Claims

1. A power supply that converts three-phase AC power to DC power, comprising:

a first, second and third converter assembly, each said converter assembly responsive to one of a first, second and third single-phase AC inputs and supplying a DC power supply output;

each converter assembly comprising;

(a) an EMI filter adapted to receive one of said first, second and third single-phase AC inputs;

(b) an AC-to-DC power factor correction circuit coupled to an output of said EMI filter;

(c) a DC-to-DC isolated converter coupled to an output of said AC-to-DC power factor correction circuit;

(d) a first and second converter output line;

wherein each of said first converter output lines are electrically coupled to one another and wherein each of said second converter output lines are electrically coupled to one another as well as to a ground connection for forming the DC power supply output;

at least one temperature sensor;

at least one current sensor;

a plurality of optocouplers arranged in a latch configuration and responsive to the at least one temperature sensor and current sensor for shutting off at least one of the DC-to-DC converters upon detection of an overcurrent or temperature condition by entering a state that causes the at least one of the DC-to-DC converters to be disabled until power is recycled.

2. The power supply of claim 1, wherein each of said single-phase AC inputs is derived from a three-phase delta AC power source.

3. The power supply of claim 1, wherein said plurality of optocouplers arranged in a latch configuration comprises a first set of three optocouplers electrically connected in a latch configuration and coupled to a corresponding one of said DC-to-DC converters.

4. A power supply for converting three-phase AC power to DC power comprising:

three single-phase AC inputs, wherein each single-phase AC input is derived from a three-phase AC power source;

three single-phase EMI filters each having an input port and an output port wherein the input port of each EMI filter is electrically coupled to one of said single-phase AC inputs;

three power factor correction AC-to-DC circuits each having an input port and an output port wherein each input port is electrically coupled to one of said EMI filter output ports;

three DC-to-DC isolated converters each having an input port and an output port wherein each output port comprises a first output line and a second output line wherein each input port is electrically coupled to one of said power factor correction AC-to-DC circuit output ports;

a first power supply output line wherein said first power supply output line is electrically coupled to each of the DC-to-DC isolated converter first output lines;

a second power supply output line wherein said second power supply output line is electrically coupled to each of the DC-to-DC isolated converter second output lines and to a ground connection;

wherein the EMI filters, power factor correction AC-to-DC circuits and DC-to-DC converters are adapted to convert 3-phase AC power to DC power;

one or more temperature-sensing circuits;

one or more current-sensing circuits;

three sets of optocouplers, each set of optocouplers electrically coupled in a latch configuration and responsive to the one or more temperature-sensing circuits and one or more current-sensing circuits for shutting off a corresponding one of the DC-to-DC isolated converters when an overcurrent or temperature condition is detected, said corresponding DC-to-DC isolated converters being disabled until power is recycled.

5. The power supply of claim 4, wherein each of said single-phase AC inputs is derived from a three-phase delta AC power source.

6. The power supply of claim 4, further comprising:

a first enclosure containing said EMI filters, said AC-DC circuits, one of said temperature-sensing circuits;

a second enclosure containing said DC-DC circuits, another of said temperature-sensing circuits, said one or more current-sensing circuits, said three sets of optocouplers; and

a cable electrically connecting said first enclosure.

7. A method of converting three-phase AC power to DC power comprising the steps of:

receiving as inputs to a power supply module three single-phase AC signals;

applying an EMI filter to each of said single-phase AC signals;

performing power factor correction on each of said single-phase signals;

converting each of said single-phase AC signals to corresponding first DC signals;

converting, in a corresponding DC-to-DC isolated converter, each corresponding first DC signal to a second DC signal;

combining each of said second DC signals to form a single DC output signal;

receiving a signal indicating detection of an overcurrent or temperature protection condition in an optocoupler latch circuit, and

disabling by the optocoupler latch circuit, each corresponding DC-to-DC isolated converter in response to receiving said signal.

8. The method of claim 7 further comprising the steps of:

reinitializing the power supply after said disabling by recycling power to said power supply.

9. The method of claim 7, wherein the receiving step further comprises receiving each of said single-phase AC signals from a three-phase delta power source.

10. A power supply temperature and overcurrent protection circuit, comprising:

a power supply module having a control line for disabling said power supply module when a predetermined condition has been met;

one or more temperature-sensing circuits;

one or more current-sensing circuits;

one or more sets of optocouplers, each set of optocouplers electrically coupled to the one or more temperature sensing circuits and the one or more current-sensing circuits and to the power supply control line;

wherein the one or more sets of optocouplers are adapted in a latch configuration such that after detection of an overcurrent or temperature condition the optocouplers will enter a state that cannot be exited without recycling power and will cause a signal to be sent over the power module control line that meets said predetermined condition for disabling the power supply.

11. The power supply of claim 10, wherein the predetermined condition comprises exceeding a predetermined current or voltage threshold.