Power factor corrected UPS maintaining neutral integrity and methods of operation thereof

• US 6,262,899 B1
• Filed: 05/02/2000
• Issued: 07/17/2001
• Est. Priority Date: 03/29/1993
• Status: Expired due to Fees

• Current Assignee: Eaton Power Quality Corporation (Eaton Corporation PLC.)
• Original Assignee: Powerware Corporation (Eaton Corporation PLC.)
• Inventors: Johnson, Robert W. Jr., Raddi, William J., Paulakonis, Joseph C.
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): Vu, Bao Q.
• Application Number:
  US09/563,462
• Time in Patent Office: 441 Days
• Field of Search: 363/17, 363/40, 363/41, 363/37, 363/47, 363/48, 363/95, 363/98, 363/131, 363/132, 307/64, 307/66
• US Class Current: 363/37
• CPC Class Codes: H02J 9/062 for AC powered loads
• 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 1/4208 Arrangements for improving power factor of AC input
• CPC Class Codes: H02M 5/458 using semiconductor devices only
• 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

An uninterrupted power supply (UPS) device with uninterrupted neutral from input to output utilizes the same converter for converting rectified AC power and battery power to positive and negative high voltage (HV) rails. A simple circuit is utilized for connecting the battery to the conversion components of the PFC circuit without adverse affect on the performance of the PFC circuit, and while holding the battery substantially connected to neutral. In a first embodiment, the circuit comprises a simple combination of four diodes and a pair of high pass capacitors arranged so that in both power line and battery supply modes the battery is balanced around neutral. In a second, preferred embodiment, one terminal of the battery is connected directly to neutral.

Claims

1. A power conversion apparatus, comprising:

an AC input port;

first and second voltage rails;

a battery input port;

an output port;

a power factor correcting converter circuit having an input and an output that is connected to the first and second voltage rails, wherein the power factor correcting converter circuit generates a DC voltage across the first and second voltage rails from a voltage at the input of the power factor correcting converter circuit responsive to a first input;

a connection circuit, coupled to the AC input port, to the battery input port and to the input of the power factor correcting converter circuit, that selectively couples the AC input port and the battery input port to the input of the power factor correcting converter circuit responsive to a second input; and

a control circuit, responsive to an AC input voltage at the AC input port, that generates the first and second inputs.

2. An apparatus according to claim 1, further comprising an output circuit, coupled to the first and second DC voltage rails, that produces an AC output voltage at an AC output port from respective first and second DC voltages at he first and second voltage rails, wherein the power factor correcting converter circuit and the output circuit maintain neutral integrity between the AC input port and the AC output port.

3. An apparatus according to claim 1, wherein the connection circuit selectively couples the AC input port and the battery input port to the input of the power factor correcting converter circuit responsive to an AC input voltage at the AC input port.

4. An apparatus according to claim 1, wherein the control circuit generates the first and second inputs such that the power factor correcting converter circuit produces respective DC voltages at the first and second voltage rails from an AC input voltage at the AC input port when the AC input voltage is in a first state, and such that the power factor correcting converter circuit produces respective DC voltages at the first and second voltage rails from a DC input voltage at the battery input port when the AC input voltage is in a second state.

5. An apparatus according to claim 4:

wherein the AC input port comprises first and second AC input nodes;

wherein the power factor correcting converter circuit comprises;

a first inductor having a first node coupled to the first voltage rail; and

a second inductor having a first node coupled to the second voltage rail; and

wherein the control circuit, when the AC input voltage is in the first state, causes the connection circuit to couple a second node of the first inductor to the first AC input node and a second node of the second inductor to the first AC input node, applies a first control signal to the power factor correcting converter circuit that causes the power factor correcting converter circuit to couple and decouple the first node of the first inductor to and from the second AC input node, and applies a second control signal to the power factor correcting converter circuit that causes the power factor correcting converter circuit to couple and decouple the first node of the second inductor to and from the second AC input node.

6. An apparatus according to claim 5:

wherein the battery input port comprises first and second battery input nodes; and

wherein the control circuit, when the AC input voltage is in the second state, causes the connecting circuit to couple the second node of the first inductor to the first battery input node and the second node of the second inductor to the second battery input node, applies a first control signal to the power factor correcting converter circuit to cause the power factor correcting converter circuit to couple and decouple the first node of the first inductor to and from the second battery input node, and applies a second control signal to the power factor correcting converter circuit to cause the power factor correcting converter circuit to couple and decouple the second node of the second inductor to and from the first battery input node.

7. An apparatus according to claim 1, further comprising an output circuit, coupled to the first and second DC voltage rails, that produces an AC output voltage from respective first and second DC voltages at the first and second voltage rails.

8. An apparatus according to claim 1, further comprising a battery coupled to the battery input port.