Multi-input power converter and uninterruptible power supply having the same

• US 7,888,819 B2
• Filed: 04/23/2008
• Issued: 02/15/2011
• Est. Priority Date: 04/23/2008
• Status: Active Grant

• Current Assignee: Eaton Phoenixtec MMPL Co. Ltd. (Eaton Corporation PLC.)
• Original Assignee: Eaton Phoenixtec MMPL Co. Ltd. (Eaton Corporation PLC.)
• Inventors: Lee, Cheng-Tan
• Primary Examiner(s): Fureman; Jared J
• Assistant Examiner(s): Fauth; Justen
• Application Number:
  US12/148,847
• Publication Number:
  US 20090267417A1
• Time in Patent Office: 1,028 Days
• Field of Search: 307/65, 307/72, 307/73, 307/75, 363/67, 363/68
• US Class Current: 307/65
• CPC Class Codes: H02J 9/062 for AC powered loads
• CPC Class Codes: H02M 1/10 Arrangements incorporating converting means for enabling loads to be operated at will from different kinds of power supplies, e.g. from ac or dc

Abstract

An uninterruptible power supply has first and second input terminals, first and second inductors, first and second AC switch units, first and second storing devices and a control unit. The first and the second inductors are electrically connected to the first and the second input terminals. The first and the second AC switch units are electrically connected to the first and the second inductors for conducting input currents. The control unit is electrically connected to the first and the second AC switch units which may be turned on and off thereby to control the first and the second inductors which charge the input currents and discharge the input currents to the first and the second storing devices.

Claims

1. A multi-input power converter, comprising:

input connection means having a first input terminal, a second input terminal and a reference ground terminal for electrically connecting to and receiving input currents from an input power system;

inductor means having a first inductor and a second inductor electrically connected to the first and second input terminals of the input connection means for charging and discharging the input currents;

switch means having a first AC switch unit and a second AC switch unit electrically connected to the inductor means for conducting the input currents;

rectifier means having

a first rectifier comprising

a ninth diode having a cathode and an anode, and the anode connected to the first inductor and the first AC switch unit; and

a tenth diode having a cathode connected to the anode of the ninth diode and having an anode; and

a second rectifier comprising

an eleventh diode having a cathode connected to the cathode of the ninth diode and having an anode; and

a twelfth diode having a cathode connected to the anode of the eleventh diode, the second inductor and the second AC switch unit and having an anode connected to the anode of the tenth diode;

output storing means having a first storing device and a second storing device electrically connected to the rectifier means for receiving the rectified inductor currents and charging voltages when the inductor means is discharged, wherein

the first storing device is connected between the cathode of the ninth diode and the reference ground; and

the second storing device is connected between the reference ground and the anode of the tenth diode; and

switch control means having a control unit electrically connected to the first and the second AC switch units of the switch means to control the inductor means charging the input currents and discharging input currents to the output storing means by controlling the first and the second AC switch units turning on and turning off.

2. The multi-input power converter as claimed in claim 1, wherein:

the input power system comprises two independent DC power supplies; and

the control unit further has a DC to DC converting process comprising steps of;

a) controlling the AC switch units turning on independently to charge the input currents to one of the first inductor and the second inductor that is electrically connected to the turned on AC switch unit; and

b) controlling the AC switch units turning off independently to discharge the input currents stored in the first and the second inductors to at least one of the first and the second storing devices.

3. The multi-input power converter as claimed in claim 1, wherein:

the input power system comprises a DC power supply,

the first and the second input terminals are electrically connected to the DC power supply; and

the control unit further has a DC to DC converting process comprising steps of;

a) controlling the AC switch units turning on together to charge the input currents into the first and the second inductors; and

b) controlling the AC switch units turning off independently to discharge the input currents stored in the first and the second inductors to the storing device that is electrically connected to the turned on AC switch unit.

4. The multi-input power converter as claimed in claim 1, wherein:

the input power system comprises a first and a second AC power supplies;

the first and the second input terminals are electrically connected respectively to line wires of the first and the second AC power supplies;

the reference ground terminal is electrically connected to a common neutral wire of the first and the second AC power supplies; and

the control unit further has a power factor correction and AC to DC converting process comprising steps of;

a) controlling the first AC switch unit turning on and off based on input voltages of the first AC power supply to charge the input currents into the first inductor, to discharge the input currents stored in the first inductor to the first storing device and to shape the input currents waveform similar to the input voltages waveform of the first AC power supply, and

b) controlling the second AC switch unit turning on and off based on input voltages of the second AC power supply to charge the input currents into the second inductor, to discharge the input currents stored in the second inductor to the second storing device and to shape the input currents waveform similar to the input voltages waveform of the second AC power supply.

5. The multi-input power converter as claimed in claim 4, wherein the first and the second AC power supplies are chosen respectively from a three-phase AC power supply.

6. An uninterruptible power supply (UPS) having a multi-input power converter as claimed in claim 1 comprising:

two batteries electrically connected together at the reference ground terminal and electrically connected respectively to the first and the second input terminals;

two DC switches electrically connected respectively between the two batteries and the first and the second input terminals to selectively provide DC electric power to the multi-input power converter;

a DC to AC converter electrically connected to the first and the second storing devices to convert the electric power stored in the first and the second storing devices into an AC output power; and

an output filtering device electrically connected to the DC to AC converter to filter the AC output power.

7. The UPS as claimed in claim 6, wherein the control unit in the multi-input power converter further has a DC to DC converting process executed when at least one of the DC switches are turned on and comprising steps of:

a) controlling the AC switch unit corresponding to the turned on DC switch turning on to store input currents into the inductor corresponding to the turned on DC switch; and

b) controlling the AC switch unit corresponding to the turned on DC switch turning off to discharge the input currents stored in the inductor corresponding to the turned on DC switch to at least one of the first and the second storing devices.

8. The UPS as claimed in claim 7, wherein:

the input power system comprises a first and a second AC power supplies;

the first and the second input terminals are electrically connected respectively to line wires of a first and a second AC power supplies;

the reference ground terminal is electrically connected to a common neutral wire of the first and the second AC power supplies; and

the control unit further has a power factor correction and AC to DC converting process executed when the DC switches are turned off and comprising steps of;

a) controlling the first AC switch unit turning on and off based on input voltages of the first AC power supply to charge the input currents into the first inductor, to discharge the input currents stored in the first inductor to the first storing device and to shape the input currents waveform similar to the input voltages waveform of the first AC power supply, and

b) controlling the second AC switch unit turning on and off based on input voltages of the second AC power supply to charge the input currents into the second inductor, to discharge the input currents stored in the second inductor to the second storing device and to shape the input currents waveform similar to the input voltages waveform of the second AC power supply.

9. An UPS having a multi-input power converter as claimed in claim 1 comprising:

a battery and a DC switch electrically connected in series and electrically connected respectively to the second and the first input terminals;

a DC to AC converter electrically connected to the first and the second storing devices to convert the electric power stored in the first and second string devices into an AC output power; and

an output filtering device connected to the DC to AC converter to filter the AC output power.

10. The UPS as claimed in claim 9, wherein the control unit further has a DC to DC converting process executed when the DC switch is turned on and comprising steps of:

a) controlling the AC switch units turning on together to charge the input currents into the first and the second inductors; and

b) controlling the AC switch units turning off independently to discharge the input currents stored in the first and the second inductors to the storing device that is electrically connected to the turned on AC switch unit.

11. The UPS as claimed in claim 9, wherein:

the input power system comprises a first and a second AC power supplies;

the first and the second input terminals are electrically connected respectively to line wires of a first and a second AC power supplies;

the reference ground terminal is electrically connected to a common neutral wire of the first and the second AC power supplies; and

the control unit further has a power factor correction and AC to DC converting process executed when the DC switch is turned off and comprising steps of;

a) controlling the first AC switch unit turning on and off based on input voltages of the first AC power supply to charge the input currents into the first inductor, to discharge the input currents stored in the first inductor to the first storing device and to shape the input currents waveform similar to the input voltages waveform of the first AC power supply, and

b) controlling the second AC switch unit turning on and off based on input voltages of the second AC power supply to charge the input currents into the second inductor, to discharge the input currents stored in the second inductor to the second storing device and to shape the input currents waveform similar to the input voltages waveform of the second AC power supply.