Switching systems and methods for use in uninterruptible power supplies

• US 10,355,521 B2
• Filed: 11/06/2017
• Issued: 07/16/2019
• Est. Priority Date: 01/23/2011
• Status: Active Grant

• Current Assignee: Alpha Technologies Services, Inc. (EnerSys)
• Original Assignee: Alpha Technologies Services, Inc. (EnerSys)
• Inventors: Richardson, James Patrick, Le, Thanh Quoc
• Primary Examiner(s): Barnie, Rexford N
• Assistant Examiner(s): Parries, Dru
• Application Number:
  US15/804,977
• Publication Number:
  US 20180062427A1
• Time in Patent Office: 617 Days
• Field of Search: 307 64
• CPC Class Codes: H02J 9/06 with automatic change-over , e.g. UPS systems
• CPC Class Codes: H02J 9/062 for AC powered loads
• CPC Class Codes: H02J 9/067 using multi-primary transformers, e.g. transformer having one primary for each AC energy source and a secondary for the loads
• CPC Class Codes: H02M 1/0035 using burst mode control
• 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
• 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
• CPC Class Codes: Y02B 70/30 Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
• CPC Class Codes: Y04S 20/20 End-user application control systems

Abstract

An uninterruptible power supply for providing an output power signal to a load comprises a ferroresonant transformer, a resonant capacitor, and an inverter. The resonant capacitor is operatively connected to the ferroresonant transformer. The inverter is operatively connected to the ferroresonant transformer. The inverter is configured to generate the output power signal based on at least one inverter control signal such that the output power signal is a quasi square wave having at least one change of phase and an upper limit. The at least one inverter control signal is held in an OFF state during at least a portion of the at least one change of phase, pulse-width modulated during at least a portion of the at least one change of phase, and held in an ON state when the output power signal is at the upper limit.

Claims

1. An uninterruptible power supply for providing an output power signal to a load comprising:

a ferroresonant transformer;

a resonant capacitor operatively connected to the ferroresonant transformer; and

an inverter operatively connected to the ferroresonant transformer, wherein;

the inverter is configured to generate the output power signal based on at least one inverter control signal such that the output power signal is a quasi square wave having at least one change of phase and an upper limit; and

the at least one inverter control signal is

held in an OFF state during at least a portion of the at least one change of phase,

pulse-width modulated during at least a portion of the at least one change of phase, and

held in an ON state when the output power signal is at the upper limit.

2. An uninterruptible power supply as recited in claim 1, in which:

the output power signal defines a plurality of changes of phase;

the at least one inverter control signal is pulse-width modulated during at least a portion of each of the plurality of changes of phase, and

held in an OFF state during at least a portion of each of the plurality of changes of phase.

3. An uninterruptible power supply as recited in claim 1, in which a duration of the ON state is varied to regulate the upper limit of the output power signal.

4. An uninterruptible power supply as recited in claim 1, in which a duty cycle of the at least one inverter control signal is varied to control a slope of the output power signal.

5. An uninterruptible power supply as recited in claim 1, in which:

the quasi square wave of the output power signal further has a lower limit;

the inverter section generates the standby power signal based on first and second inverter control signals;

the first inverter control signal is held in an ON state when the output power signal is at the upper limit; and

the second inverter control signal is held in an ON state when the output power signal is at the lower limit.

6. A method of providing an output power signal to a load comprising the steps of:

operatively connecting a resonant capacitor to a ferroresonant transformer;

operatively connecting an inverter to the ferroresonant transformer;

configuring the inverter to generate the output power signal based on at least one inverter control signal such that the output power signal is a quasi square wave having at least one change of phase and an upper limit;

holding the at least one inverter control signal in an OFF state during at least a portion of the at least one change of phase;

pulse-width modulating the at least one inverter control signal during at least a portion of the at least one change of phase; and

holding the at least one inverter control signal in an ON state when the output power signal is at the upper limit.

7. A method as recited in claim 6, further comprising the steps of:

configuring the inverter such that the output power signal defines a plurality of changes of phase;

pulse-width modulating the at least one inverter control signal during at least a portion of each of the plurality of changes of phase; and

holding the at least one inverter control signal in an OFF state during at least a portion of each of the plurality of changes of phase.

8. A method as recited in claim 6, further comprising the step of varying a duration of the ON state to regulate the upper limit of the output power signal.

9. A method as recited in claim 6, further comprising the step of varying a duty cycle of the at least one inverter control signal to control a slope of the output power signal.

10. A method as recited in claim 6, further comprising the steps of:

configuring the inverter such that the quasi square wave of the output power signal further has a lower limit;

generating the standby power signal based on a first inverter control signal that is held in an ON state when the output power signal is at the upper limit; and

generating the standby power signal based on a second inverter control signal that is held in an ON state when the output power signal is at the lower limit.

11. A method as recited in claim 6, further comprising the step of generating the standby power signal based on first and second inverter control signals such that the first and second inverter control signals are in an OFF state during at least a portion of each of the plurality of changes of phase.