Aircraft Power Supply Switching Aid Cell for Loss Reduction

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Solution Overview

Problem

Existing power supply systems for aircraft experience significant electrical energy losses due to complex switch control mechanisms, intrinsic diode conduction losses, and parasitic capacitor discharge, which are not adequately addressed by current control methods.

Innovation Solution

A power supply system with a main switching cell and a switching aid cell connected in cascade, utilizing switching capacitors in parallel with main and secondary switches, and advanced control means to minimize switching and conduction losses by controlling switches to operate at low or zero voltage and current during switching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If switches are controlled on opening and closing to regulate electrical power, then power regulation is achieved, but dynamic switching losses increase

Engineering Contradiction:
Improveelectrical power regulationVSAvoiddynamic switching losses
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The patent introduces a switching aid cell with auxiliary switches and capacitors as intermediary elements. These auxiliaries create resonant circuits that enable the main switches to turn on and off at zero voltage or zero current, thereby eliminating dynamic switching losses while maintaining power regulation capability through the main switches.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the operating parameters of the switches by using resonant oscillations to achieve zero-voltage switching (ZVS) or zero-current switching (ZCS). The switching aid cell modifies the voltage and current waveforms so that switching occurs at optimal points in the oscillation cycle, transforming hard switching into soft switching.

Inventive Principle:
Principle #35Parameter changes

2Power

If intrinsic diodes are used to conduct load current for voltage resonance, then voltage resonance is achieved, but conduction losses in diodes and switches increase

Engineering Contradiction:
Improvevoltage resonanceVSAvoidconduction losses
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The patent extracts the diode conduction function from the intrinsic diodes of the main switches and transfers it to dedicated auxiliary switches in the switching aid cell. These auxiliary switches are specifically designed to handle the resonant current, allowing the main switches to operate with lower conduction losses while still achieving the necessary voltage resonance.

Inventive Principle:
Principle #2Taking out (Extraction)

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 reduces electrical energy losses by minimizing switching and conduction losses, simplifying switch control, and eliminating the need for low-recovery diodes, thereby enhancing efficiency and reducing the number of system components.

Implementation Method 1

the connecting branch comprising a switching coil

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

switching capacitors in parallel with main and secondary switches

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP2747266B1Switching power supply system and aircraft including such a system
Publication Date: 2018.08.22 THALES SA
  • EP2747266B1 patent drawingFigure 1
  • EP2747266B1 patent drawingFigure 2
  • EP2747266B1 patent drawingFigure 3

AI summary

The system (4) has a main switching cell (6) including two main branches (14, 16) having respective main switches (T1, T2). A switching aid cell (10) includes two secondary branches (20, 22) having respective secondary switches (T3, T4). A connecting branch (24) connects the switching aid cell to the main switching cell, where the connecting branch includes a switching coil (L1). The switching aid cell includes a switching capacitor (C1) placed in parallel to one of the secondary switches, and another switching capacitor (C2) arranged in parallel to one of the main switches.