Universal Aircraft Power Supply with Power Factor Correction

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Solution Overview

Problem

Existing aircraft power supplies do not effectively correct power factor and reduce harmonic distortion of rectified AC current, limiting their efficiency and performance when operating on either 115 V AC or 28 VDC power buses.

Innovation Solution

A power supply system that includes an AC/DC switchover subcircuit, power factor correction subcircuit, and DC-DC step-down converter, capable of connecting to either aircraft AC or DC power buses, filters incoming power, converts AC to DC, and corrects power factor while reducing harmonic distortion, ensuring stable voltage output for aircraft-mounted devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If power factor correction circuitry is added to AC/DC aircraft power supplies, then power factor and harmonic distortion are improved, but device complexity increases

Engineering Contradiction:
Improvepower factor correctionVSAvoidcircuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a universal power supply system that can operate from both AC and DC aircraft power buses using a single integrated architecture. The power factor correction circuitry is designed to work seamlessly with both AC and DC inputs, eliminating the need for separate AC-only and DC-only power supply systems. This multi-functionality approach resolves the contradiction by consolidating multiple functions into one system, improving reliability without proportionally increasing complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the AC power conversion path and DC power conversion path into a single integrated power supply system. The power factor correction circuitry is combined with the existing AC-DC conversion and DC regulation circuits, creating a unified architecture that handles both AC and DC inputs. This merging approach improves power factor correction capability while avoiding the complexity of maintaining completely separate AC and DC power supply systems.

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If a single power supply system supports both AC and DC power buses, then adaptability is improved, but circuit complexity increases

Engineering Contradiction:
ImproveAC/DC power bus compatibilityVSAvoidpower supply circuit complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent designs a universal power supply system with a single integrated architecture that accepts both AC and DC aircraft power bus inputs. The system uses common components such as the power factor correction circuitry, DC-DC converter, and control logic for both AC and DC operating modes. This multi-functionality enables the power supply to adapt to different power sources without requiring completely separate circuit paths, thereby improving adaptability while controlling complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent implements dynamic switching capability that allows the power supply to automatically detect and adapt between AC and DC power bus inputs. The system dynamically reconfigures its operating mode based on the detected input type, optimizing performance for each power source. This dynamic adaptability resolves the contradiction by enabling a single system to handle multiple power sources through intelligent switching rather than requiring fixed, complex dual-path architecture.

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system provides efficient power conversion and correction, ensuring stable operation of aircraft devices by filtering and converting power from both AC and DC sources, thereby improving power factor and reducing harmonic distortion, enhancing overall system efficiency and reliability.

Implementation Method 1

a first subcircuit having an input and an output, the first subcircuit configured to accept an AC power signal, convert the AC power signal to a lower voltage which is approximately equal in magnitude to a voltage supplied by the aircraft's DC power bus, and output a lower voltage rectified AC power signal

Methodology Applied
Scientific EffectRectification:

Implementation Method 2

a power factor correction subcircuit having an input connected to the switchover output, and further having an output, the power factor correction subcircuit configured to correct a power factor of a lower voltage rectified AC power signal

Methodology Applied
Scientific EffectPower factor correction:

Implementation Method 3

a DC-DC step-down converter having an input connected to the output of the power factor correction subcircuit, and further having a system voltage output, the DC-DC step-down converter configured to reduce the first voltage to a second voltage lower than said first voltage

Methodology Applied
Scientific EffectVoltage conversion:

Data Source

PatentEP2013964B1Universal ac or DC aircraft device power supply having power factor correction
Publication Date: 2015.04.08 ROSEMOUNT AEROSPACE INC
  • EP2013964B1 patent drawingFigure 1
  • EP2013964B1 patent drawingFigure 2
  • EP2013964B1 patent drawingFigure 3

AI summary

An aircraft device power supply is capable of connecting to either an AC or a DC power bus provided on an aircraft. When connected to an aircraft's AC power bus, an AC power signal is EMI-filtered, stepped down in voltage to the same voltage as that of the DC power bus, and then rectified. When connected to an aircraft's DC power bus, a DC power signal is EMI-filtered before it is merged with the rectified AC power signal via an AC/DC switchover subcircuit. The output of the AC/DC switchover subcircuit is input to a power factor correction subcircuit which outputs a boosted DC voltage, regardless of which of the AC or DC aircraft power buses is connected to the power supply. A step down converter reduces the boosted DC voltage to a lower, system voltage which may then be further reduced or modified, as appropriate for device to be powered.