Pulsed Primary Conductor for Contactless Energy Transmission

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Solution Overview

Problem

Existing contactless energy transmission systems face high costs and ohmic losses due to the need for large cross-sectional primary conductors to handle high currents, and they often result in permanent arcing and safety hazards when faults occur.

Innovation Solution

The system regulates the pulse width and amplitude of the alternating current in the primary conductor, allowing for pulsed operation that minimizes ohmic losses, reduces arcing, and enhances safety by briefly interrupting current flow during faults, while also enabling efficient energy transmission and information transfer through inductive coupling with movable and rotatable secondary coils.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If high currents are used in the primary conductor to supply mobile devices, then energy transmission capability is improved, but ohmic losses increase and costs increase due to large cross-section requirements

Engineering Contradiction:
Improveenergy transmission capabilityVSAvoidohmic losses
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The patent applies pulsed current operation where the primary conductor is supplied with periodic current pulses instead of continuous current. The pulse width modulation controls the duty cycle to match the energy buffer charging requirements, reducing average current and ohmic losses while maintaining sufficient energy transmission capability. The pulse frequency and width are adjusted based on the energy buffer state and consumer power requirements.

Inventive Principle:
Principle #19Periodic action

2Reliability

If continuous current is supplied to the primary conductor, then stable energy transmission is achieved, but arcing occurs during faults and safety is compromised

Engineering Contradiction:
Improvestable energy transmissionVSAvoidarcing during faults
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system uses periodic current pulses with controllable duty cycles. During normal operation, the pulse width provides stable energy transmission by maintaining sufficient average current. During faults, the periodic nature with zero-crossing intervals naturally extinguishes arcs, and the pulse width can be reduced or the frequency increased to minimize current presence during fault conditions, enhancing safety.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system dynamically adjusts the pulse width and pulse frequency based on real-time conditions including energy buffer charge level, consumer power requirements, and fault detection. This dynamic control allows the system to optimize between stable energy transmission and arc suppression by adapting the current waveform characteristics to operational needs.

Inventive Principle:
Principle #15Dynamics

3Power

If large cross-section primary conductors are used to handle high currents, then current carrying capacity is improved, but system costs increase

Engineering Contradiction:
Improvecurrent carrying capacityVSAvoidsystem costs
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

By using pulsed current operation with duty cycle control, the average current in the primary conductor is significantly reduced compared to continuous current operation. This allows the use of smaller cross-section conductors that are less expensive while still achieving the required energy transmission capability through increased peak currents during pulse periods. The energy buffer compensates for the intermittent power delivery.

Inventive Principle:
Principle #19Periodic action

4Loss of energy

If pulsed operation is implemented to reduce ohmic losses, then energy efficiency is improved, but current control complexity increases

Engineering Contradiction:
Improveohmic lossesVSAvoidcurrent control complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The system incorporates feedback control where the pulse width and pulse frequency are dynamically adjusted based on monitoring of the energy buffer charge level and consumer power requirements. This feedback mechanism simplifies the control complexity by using straightforward sensing and adjustment logic rather than complex control algorithms, while still achieving optimal pulse parameters for minimizing ohmic losses.

Inventive Principle:
Principle #23Feedback

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

This approach reduces ohmic losses, lowers costs, and improves safety by minimizing permanent current flow, allowing for efficient contactless energy supply to movable loads and reducing the risk of arcing during faults, while maintaining high efficiency and adaptability to varying power requirements.

Implementation Method 1

a feed-in (1) that impresses a medium-frequency alternating current into an elongated primary conductor (2), to which at least one secondary coil (3) for supplying a consumer is inductively coupled

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP1905142B1Contactless energy transmission system and method for the operation of such a system
Publication Date: 2019.02.27 SEW EURODRIVE GMBH & CO KG
  • EP1905142B1 patent drawingFigure 1a~1b
  • EP1905142B1 patent drawingFigure 1c
  • EP1905142B1 patent drawingFigure 2

AI summary

Disclosed is a contactless energy transmission system comprising a supply that injects a medium-frequency alternating current into an elongate primary conductor to which at least one secondary coil is inductively coupled in order to feed power to a consumer. Said supply is configured such that the alternating current can be pulse width modulated and/or amplitude modulated.