Uninterruptible power supply with energy conversion and enhancement

• US 4,719,550 A
• Filed: 09/11/1986
• Issued: 01/12/1988
• Est. Priority Date: 09/11/1986
• Status: Expired due to Term

• Current Assignee: Liebert Corporation (Vertiv Holdings Co.)
• Original Assignee: Liebert Corporation (Vertiv Holdings Co.)
• Inventors: Powell, Jeffrey M., Gephart, Don A.
• Primary Examiner(s): Salce, Patrick R.
• Assistant Examiner(s): STERRETT, JEFFREY L
• Application Number:
  US06/906,176
• Time in Patent Office: 488 Days
• Field of Search: 307/46, 307/48, 307/66, 363/37
• US Class Current: 363/37
• CPC Class Codes: H02J 9/062 for AC powered loads
• CPC Class Codes: H02M 5/44 using discharge tubes or semiconductor devices to convert the intermediate dc into ac

Abstract

A power supply control is disclosed which performs in conjunction with an a.c. source as may be provided by a utility line input. This line input is directed through a converter which reflects or mirrors an a.c. signal into the line input mimicing it in all aspects except that of amplitude. The opposite side of the bi-directional device is coupled to a node connection which further is coupled to an energy reservoir present as a rechargeable storage battery. An output converter device serves to develop a desired a.c. output employing the energy at the node connection. Energy transfer into the node is provided by controlling the amplitude of the input converter such that it is slightly less than that of the input utility. The apparatus is modular in design such that it may assume a variety of configurations employing either a.c. or d.c. node connections.

Claims

1. Power supply control apparatus employable with an a.c. source input of given phase, frequency and amplitude to provide a regulated output to a load, comprising:

rechargeable storage battery means having a given energy level and a capacity for providing energy in the form of direct current;

d.c.-to-a.c. converter means for providing a d.c. side coupled with said storage battery means and an a.c. side;

node means in energy transfer communication with said d.c. side of said d.c.-to-a.c. converter means for deriving an a.c. node connection exhibiting a predetermined a.c. energy level;

an input a.c.-to-a.c. converter including a first side connectable with said a.c. source input and a second side associated in energy transfer relationship with said a.c. node connection and controllable to provide at said first side a control a.c. signal in select phase relationship with said given phase and of select amplitude;

an output a.c.-to-a.c. converter having an input side coupled with said a.c. node connection and an output side connectable with said load for employing said energy at said node to derive said output to said load; and

control means responsive to said a.c. source given amplitude, to said node means a.c. energy level, and to said rechargeable storage battery means given energy level for controlling said input a.c.-to-a.c. converter to derive a said control a.c. signal select amplitude of value below said a.c. source given amplitude to effect maintenance of said a.c. node means predetermined a.c. energy level and maintenance of said rechargeable battery means given energy storage capacity.

2. The apparatus of claim 1 in which said control means is responsive in the absence of said a.c. source input to provide an effective maintenance of said a.c. node means predetermined a.c. energy level from said rechargeable storage battery means.

3. The apparatus of claim 1 in which:

said a.c. node connection comprises transformer means having an input winding, a center winding, and an output winding mutually associated in energy transfer relationship;

said input a.c.-to-a.c. converter means comprises;

an a.c.-to-d.c. input converter having an a.c. side connectable with said a.c. source input and a d.c. side, and

a d.c.-to-a.c. input converter having a d.c. side coupled with said a.c.-to-d.c. input converter d.c. side and having an a.c. side deriving an a.c. signal of first predetermined frequency coupled with said input winding;

said output a.c.-to-a.c. converter means comprises;

an a.c.-to-d.c. output converter having an a.c. side coupled with said a.c. node connection and a d.c. side providing a d.c. output, and

d.c.-to-a.c. output converter means having a d.c. side coupled with said a.c.-to-d.c. output converter means d.c. output and an a.c. side for providing an a.c. output connectable with said load.

4. The apparatus of claim 1 in which said a.c. node connection comprises transformer means having an input winding coupled with said input a.c.-to-a.c. converter second side, a center winding coupled with said d.c.-to-a.c. converter means a.c. side, and an output winding coupled with said output a.c.-to-a.c. converter input side.

5. Power supply control apparatus employable with an a.c. source input of given frequency and amplitude for providing a regulated output to a load, comprising:

battery means of given storage level and capacity for providing a rechargeable storage reservoir;

node means for establishing a d.c. node connection having a predetermined energy level;

input converter means coupled with a select impedance between said node connection and said a.c. source and controllable to provide at said input a control a.c. signal in select phase relationship with said given phase and of select amplitude;

bi-directional output converter means coupled between said node connection and said load for employing said energy at said node to derive said output to said load;

bi-directional reservoir inverter means having a d.c. side coupled with said battery means, including inverter switching means actuable at a select frequency to provide a time varying output of given phase;

bi-directional a.c.-to-d.c. converter means having an a.c. side responsive to said time varying output, a d.c. side coupled in energy transfer relationship with said node connection and including converter switching means controllable to derive a select phase relationship of said a.c. side with respect to said time varying output given phase; and

control means for controlling said converter switching means to supply energy to said node connection to maintain said energy level by effecting a selectively lagging said phase relationship of said converter means a.c. side with respect to said time varying output given phase.

6. The power supply control apparatus of claim 5 in which said control means is responsive in the presence of said a.c. source input to maintain said battery means given storage level by effecting an altering of said selective lagging phase relationship.

7. The power supply control apparatus of claim 6 in which said control means is responsive to maintain said node means energy level in the presence of said a.c. source input by selectively adjusting said select phase relationship and said select amplitude of said input converter means control a.c. signal.

8. The power supply control apparatus of claim 5 in which:

said bi-directional a.c.-to-d.c. converter means includes;

first capacitor means for selectively storing energy from said source;

second capacitor means for selectively storing energy from said source;

said inverter switching means includes first switching means for connection with said source in a given polar sense and actuable into a conductive state, and second switching means for connection with said source in a polar sense opposite said given polar sense and actuable into a conductive state;

first inductive winding means coupled with said first switching means and first and second capacitor means;

second inductive winding means coupled with said second switching means and said first and second capacitor means; and

said control means includes means for actuating said first switching means to effect current conduction from said first capacitor means through said first inductive winding means and, simultaneously, to effect current conduction from said second capacitor means through said second inductive winding means, and for alternately actuating said second switching means to effect current conduction from said first capacitor means through said second inductive winding means and, simultaneously, to effect current conduction from said second capacitor means through said first inductive winding means.

9. Power supply control apparatus employable with an input a.c. source of given frequency and amplitude for providing a regulated output to a load, comprising:

positive and negative rail means for establishing a d.c. node connection having a predetermined effective energy level;

capacitor means coupled with said rail means for providing energy storage at said node connection;

an input converter including first switching means coupled with said rail means and connectable with said input a.c. source and controllable for applying an a.c. signal of select amplitude to said source at said given frequency and in select phase relationship therewith;

an output converter including second switching means coupled with said rail means, energizable therefrom, connectable with said load and controllable for applying an a.c. output thereto;

battery means of given storge level and capacity for providing a rechargeable energy reservoir;

voltage level adjustment means having primary and secondary sides for selectively boosting voltages asserted at said primary side;

bi-directional reservoir inverter means having a d.c. side coupled with said battery means and an a.c. side coupled with said voltage level adjustment means primary side for applying an a.c. output of given phase and frequency thereto;

bi-directional a.c.-to-d.c. rectifier means having controllable third switching means coupled with said voltage level adjustment means secondary side and said rail means for association in energy transfer relationship with said d.c. node connection; and

control means responsive to said a.c. source given amplitude and frequency and to said rail means effective energy level when below said predetermined energy level to apply a select phase lag with respect to said bidirectional a.c.-to-d.c. rectifier means controllable third switch means and said bidirectional reservoir inverter means to derive an effective said predetermined energy level at said node connection.

10. Power supply control apparatus employable with an input a.c. source of given frequency and amplitude for providing a regulated output to a load, comprising:

positive and negative rail means for establishing a d.c. node connection having an effective predetermined energy level;

capacitor means coupled with said rail means for providing energy storage at said node connection;

an input converter including first switching means coupled with said rail means and connectable with said input a.c. source and controllable for applying an a.c. signal of select amplitude to said source at said given frequency and in select phase relationship therewith;

an output converter including second switching means coupled with said rail means, energizable therefrom, connectable with said load and controllable for applying an a.c. output thereto;

battery means of given storage level and capacity for providing a rechargeable energy reservoir;

voltage level adjustment means having primary and secondary sides for selectively boosting voltages asserted at said primary side;

bi-directional reservoir inverter means having a d.c. side coupled with said battery means and an a.c. side coupled with said voltage level adjustment means primary side for applying an a.c. output of given phase and frequency thereto;

bi-directional a.c.-to-d.c. rectifier means having controllable third switching means coupled with said voltage level adjustment means secondary side and said rail means for association in energy transfer relationship with said d.c. node connection; and

control means responsive to said a.c. source given amplitude and frequency and to said rail means energy level for controlling said first switching means to derive a said a.c. signal of amplitude value below that of said input a.c source selected to effect the passage of energy to said node connection to effectively maintain said predetermined energy level, and to control said bidirectional rectifier third switching means as a synchronous rectifier in phase coincidence with said a.c. output given phase in the presence of adequate said passage of energy from said input a.c. source.

11. The power supply control apparatus of claim 10 in which said control means is responsive in the presence of a said node connection energy level below said predetermined energy level to apply a select phase lag control of said bidirectional a.c.-to-d.c. rectifier means controllable third switching means to effect return of said node connection to said predetermined energy level.

12. The power supply control apparatus of claim 10 in which said control means includes a first triangle waveform generator for deriving a first triangle waveform signal having an amplitude proportional to the voltage level at said node connection, oscillator means responsive to said input a.c. source for deriving a first control a.c. signal of frequency corresponding to said given frequency, first comparator means responsive to said first control a.c. signal and said first triangular waveform signal for deriving an output pulse width modulation signal, and first driver means responsive to said output pulse width modulation signal for controlling said output inverter second switching means.

13. The power supply control apparatus of claim 10 in which said control means includes a triangle waveform generator for deriving a triangle waveform signal having an amplitude proportional to the difference extant between the instantaneous energy level at said node connection and said predetermined energy level, means deriving a control a.c. signal proportional with said input a.c. source, comparator means responsive to said control a.c. signal and said triangular waveform signal for deriving an input pulse width modulation signal, and driver means responsive to said input pulse modulation signal for controlling said input inverter first switching means.

14. The power supply control apparatus of claim 10 in which said control means includes:

a first triangle waveform generator for deriving a first triangle waveform signal having an amplitude proportional to the voltage level at said node connection, oscillator means responsive to said input a.c. source for deriving a first control a.c. signal of frequency corresponding to said given frequency, first comparator means responsive to said first control a.c. signal and said first triangular waveform signal for deriving an output pulse width modulation signal, and first driver means responsive to said output pulse width modulation signal for controlling said output inverter second switching means; and

a second triangle waveform generator for deriving a second triangle waveform signal having an amplitude proportional to the difference extant between the instantaneous energy level at said node connection and said predetermined energy level, means deriving a second control a.c. signal proportional with said input a.c. source, second comparator means responsive to said second control a.c. signal and said second triangular waveform signal for deriving an input pulse width modulation signal, and second driver means responsive to said input pulse width modulation signal for controlling said input inverter first switching means.

15. The power supply control apparatus of claim 14 in which said control means is responsive in the presence of a said node connection energy level below said predetermined energy level to apply a select phase lag control of said bidirectional rectifier third switching means to effect return of said node connection to said predetermined energy level.

16. The power supply control apparatus of claim 10 in which:

each said first and second switching means includes a solid-state switch having gate, source, and drain terminals and actuable in response to an applied switching logic signal of select modulation frequency; and

said control means includes a driver circuit coupled in actuating relationship with each said solid-state switch comprising;

input circuit means responsive to said applied switching logic signal for deriving a first on logic condition;

memory capacitor means chargeable for deriving a second on logic condition;

charge switching means responsive to said first on logic condition for effecting a rapid charge of said memory capacitor means;

logic gate means responsive to the simultaneous presence of said first and second logic conditions for deriving an on switching condition;

drive switch means coupled with said gate and source terminals and responsive to said on switching condition for applying a gating voltage thereacross to effect said actuation of said solid-state switch;

threshold responsive network means having an input responsive to voltage levels at said drain terminal for providing a disable output when said levels exceed a predetermined value; and

shunt means coupled with said memory capacitor means for effecting the rapid discharge thereof in response to said disable output.

17. The power supply control apparatus of claim 16 including impedance means coupled in charging relationship with said memory capacitor means for effecting the charge thereof over an interval representing a modulation frequency less than said select modulation frequency.

18. The power supply control apparatus of claim 16 including delay network means coupled with said threshold responsive network means input for selectively delaying the assertion of said voltage levels of said drain terminal thereto.

19. Power supply control apparatus employable with an a.c. source input of given phase frequency and amplitude to provide a regulated output to a load, comprising:

an input a.c.-to-d.c. converter having an a.c. side coupled with said a.c. source input and a d.c. side and controllabe to provide at said a.c. side a control a.c. signal in select phase relationship with said given phase and of select amplitude;

rechargeable storage battery means having a given energy level and a capacity for providing energy in the form of direct current;

node means in energy transfer communication with said d.c. side of said input a.c.-to-d.c. converter and with said rechargeable storage battery means for deriving a node connection exhibiting a predetermined energy level;

an output d.c.-to-a.c. converter having a d.c. side coupled with said node connection and an a.c. side deriving a first output a.c. signal of predetermined frequency selected having a value greater than said given frequency;

isolation transformer means having a primary winding coupled to receive said first output a.c. signal and having a secondary winding;

a.c.-to-d.c. converter means having an a.c. side coupled with said isolation transformer means secondary winding and a d.c. side for providing a d.c. output;

d.c.-to-a.c. converter means having a d.c. side coupled in energy receiving relationship with said d.c. output and an a.c. side deriving a second a.c. output connectable with said load; and

control means responsive to said a.c. source given amplitude, to said node means energy level, and to said rechargeable storage battery means given energy level for controlling said input d.c.-to-a.c. converter to derive a said control a.c. signal select amplitude of value below said a.c. source given amplitude to effect maintenance of said node means predetermined energy level and maintenance of said rechargeable storage battery means given energy capacity.