Feed-forward control of aircraft bus dc boost converter

• US 5,982,156 A
• Filed: 04/15/1997
• Issued: 11/09/1999
• Est. Priority Date: 04/15/1997
• Status: Expired due to Fees

• Current Assignee: United States Air Force (Government of the United States of America)
• Original Assignee: United States Of America As Represented By The Secretary Of The Air Force
• Inventors: Massarini, Antonio, Cravens, Robert C. II, Weimer, Joseph A., Kazimierczuk, Marian K.
• Primary Examiner(s): STERRETT, JEFFREY L
• Application Number:
  US08/843,428
• Time in Patent Office: 938 Days
• Field of Search: 307/9.1, 307/11, 307/12, 307/18, 307/24, 323/222, 323/282, 323/288, 323/299, 323/351
• US Class Current: 323/222
• CPC Class Codes: H02M 1/0022 the disturbance parameters being input voltage fluctuations
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators

Abstract

An open loop control arrangement for an electrical energy flow-controlling circuit coupling the varying terminal voltage of an energy storing capacitor to a fixed voltage direct current aircraft energy supply bus in order to supplement bus voltage transients. The open loop control arrangement allows energy flow from the varying terminal voltage of the capacitor to the fixed bus voltage by providing a time varying pulse modulation cycle in an energy conveying and voltage changing inductive element located in the energy coupling path. The open loop control arrangement senses input voltage rather than output voltage of the coupling circuit in what is termed a "feed forward " output regulation algorithm. A transistorized and integrated circuit inclusive preferred embodiment of the invention is disclosed in which a disconnect of the inductance from the aircraft supply bus is accomplished during shunt path inductance energy charging portions of an operating cycle.

Claims

1. Direct current aircraft electrical energy distribution apparatus comprising the combination of:

a source of direct current electrical energy located in a central portion of said aircraft;

an electrical bus having an array of electrical bus conductors, including an electrically insulated conductor, connected with said source of direct current electrical energy, extending throughout said aircraft including less central portions of said aircraft, and connected in energizing relationship with a plurality of aircraft electrical load devices disposed throughout said aircraft;

a plurality of electrical energy storage devices located at selected distributed locations disposed throughout said aircraft and connected locally to said array of electrical bus conductors at each said selected distributed location, said electrical energy storage devices including a super capacitor element and an energy coupling voltage boost electronic circuit communicating a transient flow of electrical energy from said super capacitor to said electrical bus conductors;

said energy coupling electronic circuit comprising an electrical inductance element connected with said super capacitor and in series with said flow of electrical energy from said super capacitor to said electrical bus conductors, an electrical switching element connected with said electrical inductance element and generating electrical current undulations in said inductance element, and an electrical voltage regulator controller of pulse width time parameters in said electrical inductance element electrical current undulations;

said electrical voltage regulator controller including a combination pulse width modulation and regulator output voltage level reference signal waveform source and being complemented pulse width modulation time parameter-responsive to super capacitor stored-energy voltage levels appearing at an input port terminal of said electrical inductance element.

2. The direct current aircraft electrical energy distribution apparatus of claim 1 wherein said electrical voltage regulator controller is an open loop regulator circuit generating a boosted controlled output voltage from a varying input voltage.

3. The direct current aircraft electrical energy distribution apparatus of claim 1 wherein said electrical voltage regulator controller includes a periodic waveform generating electrical circuit and electrical circuitry modulating pulse width time parameters of a periodic waveform generated by said periodic waveform generating electrical circuit.

4. The direct current aircraft electrical energy distribution apparatus of claim 1 wherein said super capacitor element has an electrical size in excess of one farad.

5. The direct current aircraft electrical energy distribution apparatus of claim 1 wherein said aircraft electrical load devices include both rotating electrical machine and electronic circuit loads.

6. The direct current aircraft electrical energy distribution apparatus of claim 1 wherein said electrical voltage regulator controller further includes a series-connected second electrical switching element also connected with said output node of said electrical inductance element and a shunt-connected energy storage element connected with an output node of said second electrical switching element.

7. The direct current aircraft electrical energy distribution apparatus of claim 6 wherein said second electrical switching element comprises an electrical diode element.

8. The direct current aircraft electrical energy distribution apparatus of claim 1 wherein said source of direct current electrical energy includes one of an electrical battery, a rotating electrical machine having direct current electrical output and a chemical reaction-inclusive energy source.

9. The direct current aircraft electrical energy distribution apparatus of claim 1 wherein said electrical bus comprises a single electrically insulated conductor and an aircraft frame-inclusive common return conductor.

10. The method of energizing a combination of electrical transient-generating and transient intolerant direct current electrical loads located at electrical inductance and electrical resistance-isolated points along an aircraft energy supply bus with electrical energy of attenuated electrical transient voltage variation, said method comprising the steps of:

supplementing electrical energy supplied via said aircraft energy supply bus to said electrical inductance and electrical resistance isolated electrical loads with additional electrical energy previously removed from said bus at a slow and controlled low current removal rate and held in storage adjacent one of said electrical transient-generating load and said transient intolerant electrical loads;

storing said previously removed electrical energy in an electrical super capacitance storage element located adjacent one of said electrical transient-generating load and said electrical transient intolerant electrical loads;

operating said electrical capacitance storage element over a super capacitance change of voltage range capable of exchanging at least one half the energy stored in said electrical super capacitance storage element, a range exceeding electrical voltage transient amplitudes acceptable at said electrical transient intolerant electrical load;

coupling energy from said electrical super capacitance storage element to said energy supply bus with an electronic switching circuit-modulated electrical inductive element of controllable coupling characteristics, an element also located adjacent one of said electrical transient-generating load and said transient intolerant electrical load;

controlling said electrical capacitance storage element to aircraft energy supply bus controllable coupling characteristics according to an aircraft energy supply bus transient-attenuating open loop control algorithm, an algorithm having complemented duty cycle to output voltage characteristics and determinative of pulse width time parameters of said electrical inductive element modulation in response to electrical charge remaining in said super capacitance element;

said open loop control algorithm generating longer, inductive element energy-increasing, closure times of a shunt connected transistor switch in response to decreases in electrical charge remaining in said super capacitance element;

disconnecting said inductive element from said aircraft energy supply bus during said inductive element energy-increasing closure times of said shunt connected transistor switch in an operating cycle of said electronic switching circuit modulation.

11. The method of supplying direct current electrical energy of limited transient voltage content to electrical loads located at physically distal points along an aircraft energy supply bus, said method comprising the steps of:

supplementing electrical energy supplied via said aircraft energy supply bus to electrical transient-generating and electrical transient-sensitive electrical loads with electrical energy previously removed from said bus at a controlled removal rate and held in storage adjacent said electrical loads;

storing said previously removed electrical energy in an electrical capacitance storage element located adjacent said electrical loads;

operating said electrical capacitance storage element over a change of voltage range characteristic of removing and replacing at least one half the energy stored therein, a range exceeding electrical voltage transient amplitudes acceptable on said aircraft energy supply bus;

coupling energy from said electrical capacitance storage element to said energy supply bus of lesser voltage transient range via an electronic switching circuit-modulated electrical inductive element of variable coupling ratio, an element also located adjacent said electrical loads;

controlling said electrical capacitance storage element to aircraft energy supply bus variable coupling ratio according to an aircraft electrical energy supply bus transients-attenuating open loop control algorithm which includes a pulsating reference signal of selected constant amplitude waveform portion and complemented duty cycle to output voltage relationship included therein.

12. The method of supplying direct current electrical energy of claim 11 wherein said aircraft energy supply bus transients-attenuating open loop control algorithm is controlled in response to sampling an input voltage level received from said electrical capacitance storage element.

13. The method of supplying direct current electrical energy of claim 11 wherein said electronic switching circuit-modulated electrical inductive element of variable coupling ratio is a pulse width modulation-controlled variable coupling ratio.

14. The method of supplying direct current electrical energy of claim 13 wherein said step of coupling energy from said electrical capacitance storage element to said energy supply bus of lesser voltage transient range via an electronic switching circuit-modulated electrical inductive element of variable coupling ratio further includes the step of disconnecting said inductive element from said aircraft energy supply bus during operating cycle portions of said electronic switching circuit modulation.

15. Direct current aircraft electrical energy distribution apparatus comprising the combination of:

a source of direct current electrical energy located in said aircraft;

an electrical bus having an array of electrical bus conductors, including an electrically insulated bus conductor, connected with said source of direct current electrical energy, extending throughout said aircraft including distal portions of said aircraft, and connected in energizing relationship with a plurality-of aircraft electrical load devices disposed throughout said aircraft;

a plurality of electrical energy storage devices located at selected distributed locations disposed throughout said aircraft and connected locally to said array of electrical bus conductors at each said selected distributed location, said electrical energy storage devices including a super capacitor element and an energy coupling electronic circuit communicating a transient flow of electrical energy from said super capacitor to said electrical bus conductors;

said energy coupling electronic circuit including a voltage boosting power handling portion comprising an electrical inductance element connected between a first output terminal of said super capacitor element and an internal circuit node, a shunt disposed semiconductor switching device having switched terminals connected between said internal circuit node and a ground-connected second output terminal of said super capacitor element, a series disposed electrical diode element connected between said internal circuit node and a load connected portion of said electrically insulated bus conductor of said aircraft electrical bus;

said energy coupling electronic circuit also including a feed-forward regulator portion comprising an operational amplifier voltage comparator circuit having a voltage-sensing first input terminal connected with said super capacitor first output terminal by a resistive voltage divider network, a second input terminal connected with a source of sawtooth waveformed selectable pulse width switching signals which include a reference signal waveform portion and an output port coupled to a control terminal of said power handling portion shunt disposed semiconductor switching device and including a control algorithm having complemented duty cycle to output voltage characteristics;

said resistive voltage divider network of said feed-forward regulator portion having a voltage divider transfer function of complementing quantitative relationship with a transfer function relating super capacitor voltage and aircraft bus voltage.

16. The direct current aircraft electrical energy distribution apparatus of claim 15 wherein said energy coupling electronic circuit includes an output voltage to input voltage transfer function inclusive of a (1-D) mathematical relationship;

D being an on-duty cycle fraction of said field-effect switching transistor.

17. The direct current aircraft electrical energy distribution apparatus of claim 15 wherein:

said feed-forward regulator portion operational amplifier voltage comparator first input terminal is an inverting input terminal of said operational amplifier;

said feed-forward regulator portion operational amplifier voltage comparator second input terminal is a non-inverting input terminal of said operational amplifier;

said feed-forward regulator portion operational amplifier voltage comparator output port is coupled directly to said control terminal of said power handling portion shunt disposed semiconductor switching device.

18. The direct current aircraft electrical energy distribution apparatus of claim 15 wherein:

said feed-forward regulator portion operational amplifier voltage comparator first input terminal is a non-inverting input terminal of said operational amplifier;

said feed-forward regulator portion operational amplifier voltage comparator second input terminal is an inverting input terminal of said operational amplifier;

said feed-forward regulator portion operational amplifier voltage comparator output port is coupled to said control terminal of said power handling portion shunt-disposed semiconductor switching device through a signal polarity-inverting second operational amplifier circuit.

19. Pulse width-modulated open loop direct current to direct current converter apparatus comprising the combination of:

an energy coupling voltage boosting electronic circuit communicating a flow of undulating electrical energy between a varying energy input source and a converter output load;

an electrical inductance element, within said energy coupling electronic circuit, connected intermediate said input source and said output load in communication of said undulating flow of electrical energy;

an electrical switching element connected with said electrical inductance element and generating a regulation portion of said electrical current undulations in said inductance element;

an electrical voltage regulator controller of pulse width time parameters of said electrical inductance element regulation electrical current undulations, said voltage regulator controller including a control algorithm having a complemented duty cycle to output voltage ratio characteristic;

an electronic comparator circuit connected with a signal proportional to said varying energy input source and with a selected waveform reference signal source determinative of said regulation undulations said selected waveform reference signal including waveform segments of selected waveform amplitude disposed therein.

20. The pulse width-modulated open loop direct current to direct current converter apparatus of claim 19 wherein said electrical voltage regulator controller of pulse width time parameters includes a control algorithm wherein a complement of switch ON-duty cycle (1-D) is proportional to said varying energy input source voltage level.

21. The pulse width-modulated open loop direct current to direct current converter apparatus of claim 19 wherein said selected waveform reference signal segments of selected waveform amplitude comprise waveform undulations of a sawtooth waveshape and wherein said reference signal segments further comprise peak portions of said sawtooth waveform undulations.