Vehicle Controller Resolver Diagnostic Switching for Wireless Charging

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Solution Overview

Problem

In wireless charging systems, the magnetic field of the weakly excited supplying coil can induce diagnostic errors in the rotational position sensor of the traction motor, leading to the vehicle being put into an undriveable state, and existing solutions like shielding with steel plates increase vehicle weight and cost.

Innovation Solution

The vehicle controller switches the resolver diagnostic and servo control of the traction motors based on the gear shift position to minimize exposure to the magnetic field during positioning, avoiding resolver errors without the need for heavy shielding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If shielding with steel plates is used to protect the rotational position sensor from the magnetic field, then the sensor reliability is improved, but the vehicle weight and manufacturing cost increase

Engineering Contradiction:

Improvesensor reliabilityVSAvoidvehicle weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent extracts the rotational position sensor from the magnetic field environment by disabling its diagnostic function during wireless charging positioning. Instead of physically shielding the sensor with steel plates, the system removes the sensor's diagnostic monitoring during the positioning phase when the supplying coil's magnetic field is present, thereby eliminating the need for heavy shielding structures while maintaining system reliability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies preliminary action by switching off the resolver diagnostic function before the vehicle enters the magnetic field environment during positioning. This proactive measure prevents diagnostic errors from occurring in the first place, rather than trying to protect against them after the fact with physical shielding.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If shielding with steel plates is used to protect the rotational position sensor from the magnetic field, then the sensor reliability is improved, but the manufacturing cost increases

Engineering Contradiction:

Improvesensor reliabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses a software-based solution (switching off diagnostic function) instead of expensive physical shielding. This temporary, software-controlled approach is much cheaper than manufacturing and installing steel plate shields, while achieving the same protective effect during the positioning operation.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Measurement precision

If the resolver diagnostic is continuously monitored, then the diagnostic precision is improved, but the vehicle becomes undriveable during positioning due to false errors

Engineering Contradiction:

Improvediagnostic precisionVSAvoidvehicle drivability

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent applies dynamics by making the resolver diagnostic function dynamic rather than static. The diagnostic monitoring is automatically switched off during positioning operations and switched on during normal driving. This dynamic adjustment allows the system to maintain high diagnostic precision when needed while ensuring vehicle drivability during positioning by temporarily suspending diagnostic checks that would otherwise cause false errors.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent implements periodic action by alternately enabling and disabling the resolver diagnostic function based on the vehicle's operational state. The diagnostic is active during normal driving periods and inactive during positioning periods, creating a periodic pattern that balances diagnostic precision with operational ease.

Inventive Principle:

Principle #19Periodic 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

This approach prevents the vehicle from becoming undriveable due to resolver errors during wireless charging, reduces the risk of diagnostic failures, and avoids the weight and cost increase associated with shielding, enabling efficient and safe wireless charging.

Implementation Method 1

a receiving coil that receives power wirelessly from a supplying coil in ground equipment through electromagnetic induction

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the magnetic field of the weakly excited supplying coil can induce diagnostic errors in the rotational position sensor of the traction motor

Methodology Applied

Scientific EffectMagnetic field induction: Electromagnetic Induction

Data Source

PatentUS10836260B2Wireless power supply systems for a vehicle

Publication Date: 2020.11.17 SUBARU CORP

AI summary

A vehicle includes: a traction motor; a diagnostic module; a receiving coil; and a controller. The diagnostic module executes a diagnostic test of a rotational position sensor of the traction motor. The receiving coil receives a power wirelessly. The controller switches the diagnostic module to a state that is less likely to determine an error than normal when the receiving coil is positioned with respect to a supplying coil in a ground equipment.