EV Charging Control Apparatus Relay Failure Detection

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Solution Overview

Problem

Charging stations adapted to both mode 1 and modes 2, 3 may erroneously determine a failure in the charging station, leading to incorrect charging prohibitions due to timing issues and variations in discharging resistors among different manufacturers, making it difficult to set a uniform waiting time for determining the presence or absence of a relay failure.

Innovation Solution

A charging control apparatus with a voltage detection unit and an abnormality determination unit that estimates voltage variation over a predetermined period, determining a failure if the separation between detected and estimated voltage values exceeds a threshold, using a discharging resistor to assess relay functionality and prevent erroneous charging prohibitions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a charging station is adapted to both mode 1 and modes 2, 3, then the charging station can serve more vehicle types and charging scenarios, but it may erroneously determine a failure in the charging station due to timing issues and variations in discharging resistors

Engineering Contradiction:

Improvecharging station compatibilityVSAvoidfailure determination accuracy

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The system performs preliminary voltage detection during a predetermined period after connector connection, before final failure determination. This preliminary action captures the voltage variation characteristics that occur during the discharging phase, allowing the system to distinguish between normal discharging behavior and actual relay failures, thereby preventing erroneous failure determinations while maintaining multi-mode compatibility

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system changes the detection parameter from a simple presence/absence check to a time-varying voltage variation analysis. By monitoring how voltage changes over the predetermined period and comparing it against expected variation patterns, the system can accurately determine relay status despite timing variations and resistor differences across different manufacturers

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the charging station sets the relay to OFF state when connector is connected, then the vehicle can determine relay welding status, but it takes time before charging starts due to waiting period

Engineering Contradiction:

Improverelay failure detectionVSAvoidcharging start delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs voltage detection for a predetermined period that is sufficient to capture the essential discharging characteristics but not excessively long. This partial detection approach provides enough information to reliably determine relay status while minimizing the waiting time before charging can start, balancing reliability with time efficiency

Inventive Principle:

Principle #16Partial or excessive action

3Ease of manufacture

If different manufacturers use different discharging resistors, then each manufacturer can optimize their charging system, but it is difficult to set a uniform waiting time for determining relay failure

Engineering Contradiction:

Improvemanufacturer flexibilityVSAvoidwaiting time calibration

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The system uses a dynamic detection approach that monitors voltage variation over time rather than relying on a fixed waiting time. By detecting the actual voltage variation characteristics during the discharging period and comparing them against expected patterns, the system can adapt to different discharging resistor values from different manufacturers without requiring manufacturer-specific calibration or complex waiting time settings

Inventive Principle:

Principle #15Dynamics

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

Correctly determines the presence or absence of a charging station failure, reducing incorrect charging prohibitions and ensuring reliable charging operations by accurately assessing relay status through voltage analysis.

Implementation Method 1

a voltage detection unit for detecting a voltage applied to the charging connector

Methodology Applied

Scientific EffectVoltage detection: Electric Field

Implementation Method 2

using a discharging resistor to assess relay functionality

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS8779719B2Charging control apparatus

Publication Date: 2014.07.15 TOYOTA JIDOSHA KK

AI summary

A charging control apparatus mounted on a vehicle connected to an external charging device through a charging connector, for performing control related to charging, includes a voltage sensor for detecting a voltage applied to the charging connector, and a control device for estimating, based on variation in voltage detected by the voltage sensor during a predetermined period of time after the charging connector is connected to the vehicle, variation in voltage applied to the charging connector after a lapse of the predetermined period of time, and determining that a failure has occurred in the external charging device if a degree of separation between the variation in voltage detected by the voltage sensor after the lapse of the predetermined period of time and the estimated variation in voltage is larger than a predetermined value.