3-phase high-power UPS

• US 8,344,551 B2
• Filed: 07/28/2011
• Issued: 01/01/2013
• Est. Priority Date: 02/21/2007
• Status: Active Grant

• Current Assignee: American Power Conversion Corporation (Schneider Electric SE)
• Original Assignee: American Power Conversion Corporation (Schneider Electric SE)
• Inventors: Nielsen, Henning Roar
• Primary Examiner(s): CAVALLARI, DANIEL J
• Application Number:
  US13/192,869
• Publication Number:
  US 20110280055A1
• Time in Patent Office: 523 Days
• Field of Search: 307/82, 363/40, 363/41, 363/50, 363/56.01, 363/71, 363/131, 363/132
• US Class Current: 307/82
• CPC Class Codes: H02J 1/102 being switching converters H02J1/108, H02J1/12 take precedence
• CPC Class Codes: H02J 7/0014 Circuits for equalisation of charge between batteries
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices
• CPC Class Codes: H02J 9/062 for AC powered loads
• CPC Class Codes: H02M 5/40 with intermediate conversion into dc
• CPC Class Codes: H02M 7/487 Neutral point clamped inverters

Abstract

A 3-phase uninterruptible power supply (UPS) including first, second, and third AC/DC converters, a DC/DC converter, and at least one DC/AC converter coupled to multiple electrical buses. The first, second, and third AC/DC converters each being configured to receive AC power and to provide multiple DC signals to the multiple electrical buses. The DC/DC converter being configured to convert DC voltages present on the multiple electrical buses to a DC voltage that can be used to charge a battery. The DC/AC converter being configured to receive DC power from the multiple electrical buses and to provide an AC output. The 3-phase UPS being configured such that when suitable AC power is provided to the AC/DC converters, the DC/DC converter is configured to charge a battery, and when suitable AC power is not provided to the AC/DC converters, the DC/DC converter is configured to provide DC power to the multiple electrical buses using power provided by the battery.

Claims

1. A DC/AC converter configured to convey an AC power signal having a positive peak voltage and a negative peak voltage, the DC/AC converter comprising:

an output configured to convey the AC power signal;

first, second, third, and fourth inputs, each being configured to receive a respective input voltage;

a filter coupled to the output;

first and second switches coupled in series between the filter and the first input, the first switch being coupled to the filter;

a third switch coupled to a junction of the first and second switches and the second input;

fourth and fifth switches coupled in series between the filter and the fourth input, the fourth switch being coupled to the filter;

a sixth switch coupled to a junction of the fourth and fifth switches and the third input;

a first diode coupled in parallel with the first switch;

a second diode coupled in parallel with the second switch;

a third diode coupled in parallel with the third switch;

a fourth diode coupled in parallel with the fourth switch;

a fifth diode coupled in parallel with the fifth switch; and

a sixth diode coupled in parallel with the sixth switch.

2. The DC/AC converter of claim 1 further comprising a controller coupled to the first, second, third, fourth, fifth, and sixth switches.

3. The DC/AC converter of claim 2 wherein the controller is configured to toggle the first, second, third, fourth, fifth, and sixth switches such that the AC power signal is induced at the output.

4. The DC/AC converter of claim 3 wherein the controller is configured to toggle the first, second, third, fourth, fifth, and sixth switches such that:

the positive peak voltage of the output AC power signal is less than the DC voltage conveyed to the first input multiplied by

5. The DC/AC converter of claim 4 wherein the controller is configured to:

cause, when the AC power signal is between the DC voltages conveyed on the first and second inputs, the DC/AC converter to operate in a first state where;

the first switch is toggled on;

the second switch is repeatedly toggled on and off;

the third switch is repeatedly toggled on and off;

the fourth switch is toggled off;

the fifth switch is toggled off;

the sixth switch is toggled on;

cause, when the AC power signal is between the DC voltages conveyed on the second and third inputs, the DC/AC converter to operate in a second state where;

the first switch is repeatedly toggled on and off;

the second switch toggled off;

the third switch is toggled on;

the fourth switch is repeatedly toggled on and off;

the fifth switch is toggled off;

the sixth switch is toggled on;

cause, when the AC power signal is between the DC voltages conveyed on the third and fourth inputs, the DC/AC converter to operate in a third state where;

the first switch is toggled off;

the second switch toggled off;

the third switch is toggled on;

the fourth switch is toggled on;

the fifth switch is repeatedly toggled on and off; and

the sixth switch is repeatedly toggled on and off.

6. The DC/AC converter of claim 1 wherein the filter comprises:

an inductor coupled between the output and the junction of first and fourth switches; and

a capacitor coupled between the output and a neutral.

7. The DC/AC converter of claim 1 wherein the first, second, third, fourth, fifth, and sixth switches are configured to be controlled by a pulse width modulation (PWM) controller.

8. The DC/AC converter of claim 7 wherein the PWM controller coupled to the output and configured to control the actuation of the first, second, third, fourth, fifth, and sixth switches in accordance with a voltage level of the output.

9. The AC/DC converter of claim 1 further comprising:

a first capacitor coupled between the first and second inputs;

a second capacitor coupled between the second input and a neutral;

a third capacitor coupled between the neutral and the third input; and

a fourth capacitor coupled between the third and fourth inputs.