METHOD OF CONTROLLING AN UNINTERRUPTIBLE POWER SUPPLY APPARATUS

• US 20080012426A1
• Filed: 07/06/2007
• Published: 01/17/2008
• Est. Priority Date: 07/12/2006
• Status: Abandoned Application

• Current Assignee: Delta Electronics Incorporated
• Original Assignee: Delta Electronics Incorporated
• Inventors: Ying, Jian-Ping, Tan, Jing-Tao, Lu, Yan-Song, Yang, Jian-Ping
• Application Number:
  US11/774,277
• Publication Number:
  US 20080012426A1
• Time in Patent Office: Days
• US Class Current: 307/65
• CPC Class Codes: H02J 9/062 for AC powered loads

Abstract

A method of controlling an uninterruptible power supply apparatus (UPS) is provided. The UPS apparatus includes at least an AC input voltage, a DC input voltage and a single-phase AC/AC converter. The single-phase AC/AC converter includes an AC inductor, a bus capacitor, a boost arm, a common arm and a buck arm. The method includes steps of: controlling the bus voltage to have a DC component and full-wave rectifying component, and setting a bus voltage parameter K so that the bus voltage approaches to a full-wave rectifying voltage when K approaches to 1, wherein 0≦K≦1.

Claims

1. A method of controlling an uninterruptible power supply apparatus having a bus voltage, an AC input voltage, a DC input voltage and a single-phase AC/AC converter, the single-phase AC/AC converter including an AC inductor, a bus capacitor, a boost arm, a common arm and a buck arm, the method comprising steps of:

(a) controlling the bus voltage to have a DC voltage and a full-wave rectifying voltage; and

(b) setting a bus voltage parameter K where 0≦

K≦

1, so that the bus voltage approaches to the DC voltage when K approaches to 0 and the bus voltage approaches to the full-wave rectifying voltage when K approaches to 1;

wherein when the AC input voltage is normal, the bus voltage is rectified via the single-phase AC/AC converter to output, and when the AC input voltage is abnormal, the DC input voltage is inverted via the single-phase AC/AC converter to output.

2. The method according to claim 1, wherein the uninterruptible power supply apparatus further comprises a switch set, an AC filter and a load.

3. The method according to claim 2, wherein in step (b) when the load is light-load, the bus voltage parameter K is increased to approach to 1, and when the load is heavy-load, the bus voltage parameter K is decreased to approach to 0.

4. The method according to claim 1, further comprising a step of (c) setting a duty cycle d3 of the buck arm, a duty cycle d1 of the boost arm and a voltage gain M of the single-phase AC/AC converter to meet an equation of d3=M(1−

d1).

5. The method according to claim 4, further comprising a step of (d) defining a wave function F of the bus voltage to meet the following conditions;

when |sin(wt)|<

K, F=|sin(wt)|; and

when |sin(wt)|≧

K, F=K, wherein w is an angular velocity, and t is a passing time.

6. The method according to claim 5, wherein the duty cycle d1 of the boost arm, the voltage gain M of the single-phase AC/AC converter, the bus voltage parameter K and the wave function of the bus voltage F meet an equation d1=(2−

M)KF.

7. The method according to claim 6, further comprising a step of (d) of controlling one of boost arm and the buck arm to operate under a pulse-width-modulation mode when sin(wt)>

1/K, and controlling both of the boost arm and the buck arm to operate under pulse-width-modulation mode when sin(wt)<

1/K.

8. A method of controlling an uninterruptible power supply apparatus having a bus voltage, an AC input voltage, a DC input voltage and a single-phase AC/AC converter comprising an AC inductor, a bus capacitor, a boost arm, a common arm and a buck arm, the method comprising steps of:

(a) controlling the bus voltage and making the bus voltage have a waveform including a low slope segment and a full-wave rectifying segment;

(b) setting a bus voltage parameter K representing an amount of an output power, wherein 0≦

K≦

1; and

(c) regulating a proportion of the low slope segment and the full-wave rectifying segment within a full cycle based on a variation of the bus voltage parameter K, the waveform of the bus voltage during the low slope segment having a slope lower than a further slope of the waveform of the bus voltage during the full-wave rectifying segment;

wherein, when the AC input voltage is normal, the bus voltage is rectified via the single-phase AC/AC converter to output, and when the AC input voltage is abnormal, the DC input voltage is inverted via the single-phase AC/AC converter to output.

9. The method according to claim 8, wherein an average voltage value during the full-wave rectifying segment is larger than that during the low slope segment.

10. The method according to claim 8, further comprising a step of (d) of increasing a duration of the low slope segment and decreasing a duration of the full-wave rectifying segment when the output power decreases.

11. The method according to claim 8, wherein the waveform of the bus voltage is obtained by regulating duty cycles of the boost arm and the buck arm.

12. A method of controlling an uninterruptible power supply apparatus having a bus voltage, an AC input voltage, a DC voltage and an AC/AC converter, comprising steps of:

(a) controlling the bus voltage to have a DC voltage and a full-wave rectifying voltage; and

(b) setting a bus voltage parameter K, where 0≦

K≦

1, so that the bus voltage approaches to the DC voltage when K approaches to 0 and the bus voltage approaches to the full-wave rectifying voltage when K approaches to 1.