Inductive Rail Charging Frequency Control for Variable Air Gaps

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Solution Overview

Problem

Existing inductive energy transmission systems for rail vehicles face challenges in efficiently transmitting energy across variable distances without mechanical adjustment of the air gap, particularly in rail transport with changing loading states and limited installation space.

Innovation Solution

An inductive energy transmission arrangement that automatically adjusts the resonance point by controlling the AC voltage frequency, using a control device to maintain efficient energy transfer regardless of the air gap geometry, and includes features for overcurrent protection and bidirectional energy transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the air gap between energy transmission device and energy absorption device is adjusted mechanically to maintain predetermined distance, then energy transmission efficiency is improved, but device complexity and ease of operation deteriorate due to mechanical adjustment mechanisms

Engineering Contradiction:
Improveenergy transmission efficiencyVSAvoidmechanical adjustment mechanism
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical air gap adjustment system with an electrical control system that adapts the AC voltage frequency to maintain resonance conditions. Instead of mechanically moving components to adjust distance, the system electronically adjusts frequency parameters to compensate for variable air gaps, thereby eliminating complex mechanical mechanisms while maintaining high energy transmission efficiency.

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

Solution Approach 2:

The patent changes the operating parameter from fixed air gap distance to variable AC voltage frequency. By allowing the frequency to be dynamically adjusted based on the actual air gap conditions, the system maintains resonance and optimal energy transmission without requiring mechanical adjustment of the physical distance between components.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If data transmission between vehicle and roadside control device is made fast and reliable to react to changing distance, then energy transmission reliability is improved, but device complexity and loss of time worsen due to continuous communication requirements

Engineering Contradiction:
Improveenergy transmission reliabilityVSAvoiddata transmission system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control device autonomously determines the optimal AC voltage frequency based on measured power output values without requiring continuous bidirectional communication with the vehicle. The system performs self-adjustment by monitoring its own operating parameters and automatically tuning the frequency to maintain resonance, thereby reducing communication infrastructure complexity while ensuring reliable energy transmission.

Inventive Principle:
Principle #25Self-service

3Loss of energy

If resonance point is readjusted quickly to compensate for changing distance, then energy transmission efficiency is improved, but loss of time worsens during the adjustment process

Engineering Contradiction:
Improveenergy transmission efficiencyVSAvoidresonance adjustment time
Core Design Contradiction:
Loss of energyVSLoss of time

Solution Approach 1:

The patent implements continuous frequency adjustment during the energy transmission process rather than discrete stepwise changes. The control device continuously monitors power output and smoothly adjusts the AC voltage frequency to maintain resonance conditions, ensuring uninterrupted and efficient energy transmission while minimizing any temporal disruption during parameter adaptation.

Inventive Principle:
Principle #20Continuity of useful action

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

Enables quick, reliable, and efficient energy transmission with a simple mechanical design, maintaining optimal power transfer across varying distances and protecting against overcurrents, while allowing energy feedback and efficient operation in both directions.

Implementation Method 1

a first induction element, which serves as a transmitter of electrical energy, and a second induction element, wherein the electrical energy can be transmitted via a variable air gap from the first induction element to the second induction element

Methodology Applied
Scientific EffectMagnetic induction: Electromagnetic Induction

Implementation Method 2

the parameters of the energy transmission, in particular for forming a resonance, must be adjusted depending on the distance. This can be done, for example, by adapting the AC voltage frequency during the energy transmission

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP3126159B1Arrangement, system, and method for inductively transmitting energy for charging at least one energy store of a rail vehicle
Publication Date: 2023.07.05 SIEMENS MOBILITY GMBH
  • EP3126159B1 patent drawingFigure 1~2
  • EP3126159B1 patent drawingFigure 3
  • EP3126159B1 patent drawingFigure 4

AI summary

The invention relates to an arrangement (190) for inductively transmitting energy for charging an energy store of a rail vehicle, comprising at least one first induction element (92, 94, L01, L02) which is suitable for wirelessly transmitting energy to at least one second induction element (93, 95, L03, L04), and an inverter (121, 195), the AC voltage frequency of which can be controlled. The inverter (121, 195) is suitable for providing an AC voltage with the AC voltage frequency to the at least one first induction element (92, 94, L01, L02). The arrangement also comprises a controller which is suitable for controlling the AC voltage frequency of the inverter (121, 195) and a measuring device (120) which is suitable for ascertaining a measurement value when wirelessly transmitting energy from the at least one first (92, 94, L01, L02) to the at least one second induction element (93, 95, L03, L04) and transmitting said measurement value to the controller. The invention is characterized in that the measuring device (120) is suitable for measuring a power output value as the measurement value, the controller is suitable for adjusting down the AC voltage frequency of the inverter (121, 195) from an upper threshold until a previously specified power output value is set while energy is being transmitted, and the first induction element is paired with a track for the rail traffic. The invention further relates to a system and a method for inductively transmitting energy for charging an energy store of a rail vehicle.