MULTIVOLTAGE, REGULATED POWER SUPPLY WITH FAULT PROTECTION

• US 3,824,441 A
• Filed: 01/02/1973
• Issued: 07/16/1974
• Est. Priority Date: 01/02/1973
• Status: Expired due to Term

• Current Assignee: Albert M. Heyman, Edward H. Friedman
• Original Assignee: Albert M. Heyman, Edward H. Friedman
• Inventors: Heyman, Albert M., Friedman, Edward H.
• Primary Examiner(s): Shoop, Jr., William M.
• Application Number:
  US05/320,047
• Time in Patent Office: 560 Days
• Field of Search: 321/2,11,18,19,45C
• US Class Current: 363/37
• CPC Class Codes: H02M 3/3155 with automatic control of the output voltage or current
• CPC Class Codes: H02M 7/525 with automatic control of output waveform or frequency H02M7/517 - H02M7/523 take precedence

Abstract

A power supply for providing a plurality of regulated voltage levels while protecting the power supply from damage due to fault conditions. The power supply provides apparatus for rectifying AC input power and, by means of a DC to DC converter, supplies a DC voltages to the output terminals. A selected DC output voltage is monitored by feedback circuits. The feedback circuits control the operation of switching elements of the DC to DC converter, and therefore determine the monitored output voltage level, by increasing or decreasing the rate of operation of the switching elements. Various fault conditions, such as over and under-voltage conditions, etc., are monitored by the fault detection apparatus at the selected output voltage terminals. The detection of a fault condition causes the power supply to suspend operation. Operation of over-current condition detection apparatus is continually verified. The apparatus supplying the selected output voltage terminals simultaneously supplies the terminals providing the remainder of the plurality of output voltages. Because of the coupling of the source apparatus for the output voltage terminals, regulation of one voltage level provides regulation for each voltage level. Similarly, fault conditions at any of the voltage terminals are detected by the fault detection apparatus.

Claims

1. An electronic power supply comprising:

means for storing electronic charge, said stored charge providing a DC intermediate signal;

input means for transferring charge from an input power source and applying said charge to said storage means;

an inverter circuit comprising switching elements coupled to said storage means, said inverter circuit producing an AC signal from said DC intermediate signal;

at least one output means for producing a DC output signal from said AC signal, each of said output means coupled to said inverter circuit; and

control apparatus coupled to said output means and said inverter circuit, wherein a frequency of said AC signal is determined by a one of said DC output voltages;

wherein a first power train includes said storage means, said input means, said inverter means, and said output means, said power supply further including a second power train substantially identical to said first power train, wherein said control apparatus is also coupled to said second power train, wherein each of said output means of said first power train is coupled to a substantially equivalent output means of said second train, wherein said input means of said power train and an input means of said second power train is coupled in a series combination.

2. An electronic power supply comprising:

means for storing electronic charge, said stored charge providing a DC intermediate signal;

input means for transferring charge from an input power source and applying said charge to said storage means;

an inverter circuit comprising switching elements coupled to said storage means, said inverter circuit producing an AC signal from said DC intermediate signal;

at least one output means for producing a DC output signal from said AC signal, each of said output means coupled to said inverter circuit; and

control apparatus coupled to said output means and said inverter circuit, wherein a frequency of said AC signal is determined by a one of said DC output voltages;

said control apparatus comprising;

means for regulating voltage, said voltage regulating means determining said AC signal frequency from a comparison of said DC output voltage and a reference voltage, said voltage regulating means including;

means for producing an intermediate signal;

means for changing a frequency of said intermediate signal, a change of said frequency determined by a difference between said one DC output voltage and said reference voltage; and

means for coupling said intermediate signal to said switching elements of said inverter circuit wherein said switching elements are semiconductor-controlled rectifiers and wherein said means for coupling said intermediate signal to said switching elements further comprises;

a monostable multivibrator for producing bias pulse for each cycle of said frequency of said intermediate signal;

a counter circuit for producing a sequence of activation pulses determined by said frequencing of said intermediate signal; and

a first and a second logic AND gate for combining said bias pulses and a selected series of said activation pulses, said combination producing bias signals for placing said semiconductor-controlled rectifiers in a conducting state; and

fault detection apparatus coupled to said regulating circuit, said fault detection apparatus applying a disabling signal to said regulating circuit in response to a one of predetermined conditions in said power supply, said disabling signal suspending operation of said power supply.

3. The power supply of claim 2 wherein said input terminals of first and second logic AND gates are coupled to said fault detection apparatus, said disabling signal being a logic signal disabling said first and said logic AND gates.

4. An electronic power supply comprising:

means for storing electronic charge, said stored charge providing a DC intermediate signal;

input means for transferring charge from an input power source and applying said charge to said storage means;

an inverter circuit comprising switching elements coupled to said storage means, said inverter circuit producing an AC signal from said DC intermediate signal;

at least one output means for producing a DC output signal from said AC signal, each of said output means coupled to said inverter circuit; and

control apparatus coupled to said output means and said inverter circuit, wherein a frequency of said AC signal is determined by a one of said DC output voltages, said control apparatus comprising;

means for regulating voltage, said voltage regulating means determining said AC signal frequency from a comparison of said DC output voltage and a reference voltage, said voltage regulating means including;

means for producing an intermediate signal;

means for changing a frequency of said intermediate signal, a change of said frequency determined by a difference between said one DC output voltage and said reference voltage; and

means for coupling said intermediate signal to said switching elements of said inverter circuit;

means for activating said intermediate signal;

means for preventing application of said disabling signal to said voltage regulating means during a start-up of said power supply; and

means for resetting said voltage regulating means after said voltage regulating means has received said disabling signal, said power supply thereafter operating normally in the absence of any one of predetermined conditions; and

fault detection apparatus coupled to said regulating circuit, said fault detection apparatus applying a disabling signal to said regulating circuit in response to a one of predetermined conditions in said power supply, said disabling signal suspending operation of said power supply.

5. An electronic power supply comprising:

means for storing electronic charge, said stored charge providing a DC intermediate signal;

input means for transferring charge from an input power source and applying said charge to said storage means;

an inverter circuit comprising switching elements coupled to said storage means, said inverter circuit producing an AC signal from said DC intermediate signal, said inverter circuit including a first and a second high-Q resonant network, reactive elements in said first and said second resonant network coupled to a first and second silicon-controlled rectifier, wherein said AC signal is essentially a sine wave under normal operating conditions;

at least one output means for producing a DC output signal from said AC signal, each of said output means coupled to said inverter circuit; and

control apparatus coupled to said output means and said inverter circuit, wherein a frequency of said AC signal is determined by a one of said DC output voltages, said control apparatus comprising;

means for regulating voltage, said voltage regulating means determining said AC signal frequency from a comparison of said DC output voltage and a reference voltage; and

fault detection apparatus coupled to said regulating circuit, said fault detection apparatus applying a disabling signal to said regulating circuit in response to a one of predetermined conditions in said power supply, said disabling signal suspending operation of said power supply.

6. The power supply of claim 5 wherein said AC signal is coupled to said means for producing a DC output signal by at least one transformer, said transformers operating in a region of non-saturation, whereby regulation of said one DC output signals provides regulation for the remainder of said DC output signals.

7. An improved electronic power supply of the type comprising switching elements arranged in an inverter circuit, said inverter circuit producing an AC signal from a DC signal, and means for detecting the presence of a fault condition in said power suppLy, wherein the improvement comprises:

a voltage regulating circuit coupled to an output signal of said power supply coupled to said fault detection means, and coupled to said inverter circuit, said voltage regulating circuit controlling the operation of said inverter circuit, said voltage regulating circuit suspending operation of said inverter circuit in response to faults conditions detected by said fault detection means, said voltage regulating circuit comprising;

means for comparing said output signal of said power supply with a reference voltage;

means for controlling a frequency of an intermediate signal, said frequency control means coupled to said comparison means, said frequency control means varying said frequency in response to a signal determined by a difference between said reference voltage and said output signal;

means for activating said switching elements of said inverter circuit at a rate determined by said frequency at said intermediate signal; and

means for disabling said fault detection means during initiation of operation of said inverter circuits, said fault detection disabling means operating for a period of time sufficient to allow said power supply to achieve normal operating conditions.

8. The power supply of claim 7 further including means for resetting said fault detection means and said voltage regulating circuit upon removal of a fault condition;

activation of said resetting means permitting normal operation of said fault detection means and said voltage regulation circuit in the absence of a fault condition.

9. An electronic power supply comprising:

a storage capacitor for storing electronic charges;

a first circuit including;

a first silicon controlled rectifier (SCR), a first inductor coupled to said SCR, and a first capacitor coupled to said first SCR and said first inductor;

a second circuit including;

a second SCR, a second inductor coupled to said second SCR, and a second capacitor coupled to said second SCR and at least one of said inductors, wherein said first circuit is coupled to said storage capacitor, and wherein said second circuit is coupled to said first circuit and to said storage capacitor;

at least one rectifier/filter circuit coupled to said first and said second inductor, each of said rectifier/filter circuits supplying at least one output voltage for said power supply; and

control apparatus coupled to any one of said rectifier/filter circuits and coupled to said first and said second SCR'"'"''"'"'s, said control apparatus producing bias signals causing said first and said second SCR to become conducting sequentially, an interval between conducting states of said first and said second SCR established by said output voltage, wherein said control apparatus is disabled from producing said bias signals upon detection of preselected conditions in said power supply;

wherein said rectifier/filter circuits are coupled to at least one transformer, said transformers coupled in series between said first inductor and said storage capacitor;

wherein said reactive elements of said first and said second circuits form a high Q resonant circuit, said high Q resonant circuit supplying a substantially sinusoidal voltage across said series connected transformers.

10. The power supply of claim 9 wherein said control apparatus bias signals switch said first and said second SCR at a frequency substantially equal to a resonant frequency of said high Q circuits.

11. The power supply of claim 10 wherein said control apparatus further includes:

means for varying said switching frequency, a change in said switching frequency determined by a difference between said one output voltage and a reference voltage.

12. The power supply of claim 10 wherein said control apparatus includes means for prevention of disablement of said control apparatus upon said detection of preselected conditions during a startup period of said power sUpply.