Single-Conductor IPT Track Layout for Low Mutual Inductance

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Solution Overview

Problem

Current Inductive Power Transfer (IPT) systems for Roadway Powered Electric Vehicles (RPEVs) face challenges in achieving large horizontal tolerance and efficient power transfer due to high mutual inductance between track phases, leading to uneven power profiles and increased system complexity and cost.

Innovation Solution

The proposed IPT track arrangement features a single conductor forming overlapping loops with adjacent loops having the same polarity, reducing mutual inductance and allowing for a more compact design with parallel inverters to share the load, enhancing lateral range and power profile smoothness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional IPT track phases are used, then power transfer is achieved, but mutual inductance between phases causes uneven power profiles and increased system complexity

Engineering Contradiction:

Improvepower transfer efficiencyVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent inverts the conventional approach by using same polarity in adjacent loop portions instead of alternating polarity. This inversion reduces mutual inductance between phases from high to low levels, thereby improving power transfer efficiency while reducing system complexity and cost.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the polarity parameter of adjacent loop portions from alternating to same polarity. This parameter change fundamentally alters the magnetic field distribution and mutual inductance characteristics, enabling improved power transfer efficiency without the complications of high mutual inductance.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If track spacing is reduced for compact design, then system cost decreases, but mutual inductance between phases increases

Engineering Contradiction:

Improvesystem costVSAvoidpower transfer efficiency

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies polarity inversion to adjacent loop portions, which counteracts the increasing mutual inductance effect that would normally occur with reduced track spacing. This allows compact design with reduced spacing while maintaining low mutual inductance and high power transfer efficiency.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent converts the potentially harmful effect of reduced track spacing (increased mutual inductance) into a benefit by using same polarity configuration. The reduced spacing brings cost advantages while the same polarity arrangement ensures mutual inductance remains low, turning what would be a disadvantage into an advantage.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Adaptability or versatility

If horizontal tolerance is increased for RPEV applications, then adaptability improves, but system complexity and cost increase

Engineering Contradiction:

Improvehorizontal toleranceVSAvoidsystem complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent changes the polarity parameter to be the same in adjacent loop portions, which fundamentally improves the magnetic field distribution. This parameter change enables increased horizontal tolerance for RPEV applications while avoiding the system complexity and cost increases that would normally accompany such adaptability improvements.

Inventive Principle:

Principle #35Parameter changes

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 configuration improves the horizontal tolerance and power transfer efficiency by minimizing mutual inductance and reducing the complexity and cost of the system, while maintaining a smooth power profile across the track width.

Implementation Method 1

IPT uses a varying magnetic field to couple power across an air gap, to a load, without physical contact

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The parallel compensation capacitor C1 allows the track current, I1, to resonate, increasing the magnetic field strength in the vicinity of the track

Methodology Applied

Scientific EffectResonance: Resonance

Implementation Method 3

The IPT PU inductance, L2, is tuned for resonance with C2. This compensates for the relatively large PU leakage inductance

Methodology Applied

Scientific EffectResonance: Resonance

Data Source

PatentUS11869707B2Double conductor single phase inductive power transfer tracks

Publication Date: 2024.01.09 AUCKLAND UNISERVICES LTD

AI summary

An IPT track arrangement including a power supply and conductor electrically connected to the power supply, the conductor includes a plurality of loops located substantially adjacent one another, wherein the polarity in adjacent portions of the loops is the same, and wherein the power supply includes a one or more inverters which share the track load.