Active Rectification Control for Aircraft Power Systems

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Solution Overview

Problem

In aircraft power systems, achieving a power factor close to 1 while minimizing input current harmonics is crucial due to weight restrictions, but existing active rectification systems struggle to optimize both efficiency and weight effectively.

Innovation Solution

An active rectification system incorporating a pulse width modulation (PWM) control portion and a closed-loop vector control mechanism that detects phase angle and frequency to transform input currents into d-q components, determining duty cycles for PWM signals to align three-phase input currents with input pole voltages, thereby regulating DC voltage and improving power factor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If active rectification is used to improve power factor and reduce harmonics, then power quality improves, but system complexity increases

Engineering Contradiction:
Improveinput current harmonicsVSAvoidcontrol system complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent implements a closed-loop control system that continuously monitors the DC-link voltage and adjusts the PWM switching signals accordingly. The control portion receives feedback about the actual DC voltage level and modifies the rectifier operation to maintain the voltage within desired limits, thereby achieving both power quality improvement and stable voltage regulation without excessive complexity

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces traditional mechanical or simple electronic voltage regulation methods with a microprocessor-based control system. The control portion uses digital signal processing to generate PWM signals and implement closed-loop control, substituting complex discrete circuitry with programmable logic that achieves the same functions with reduced hardware complexity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Stability of the object's composition

If DC voltage is regulated through active control, then voltage stability improves, but control complexity increases

Engineering Contradiction:
ImproveDC voltage stabilityVSAvoidcontrol mechanism complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The control portion continuously monitors the DC-link voltage and compares it with reference values. Based on the voltage deviation, the control algorithm adjusts the PWM duty cycles to regulate the DC voltage, implementing automatic feedback control that maintains voltage stability without requiring complex manual intervention or oversized passive components

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent implements dynamic voltage regulation that adapts to changing load conditions and input voltage variations. The control system adjusts its operation in real-time based on instantaneous system state, transitioning between different control modes as needed to maintain optimal DC voltage levels under varying operating conditions

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2461469B1Active rectification control
Publication Date: 2019.01.02 HAMILTON SUNDSTRAND CORP
  • EP2461469B1 patent drawingFigure 1
  • EP2461469B1 patent drawingFigure 2
  • EP2461469B1 patent drawingFigure 3

AI summary

An active rectification system (100) includes an active rectifier (102), a pulse width modulation (PWM) control (101), and a closed loop vector control (400). The PWM control portion (101) is configured to control switching of the active rectifier and the closed loop vector control is configured to generate the required duty cycles for the PWM signals that regulate the DC voltage output and force a three-phase current input of the active rectifier to align with a three-phase pole voltage input of the active rectifier.