Vehicle Charging Apparatus Dynamic Current Control

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Solution Overview

Problem

Existing vehicle charging systems are unable to continue charging when there are fluctuations in external electric power supply voltage or frequency, leading to potential interruptions in vehicle travel distance and auxiliary load functionality.

Innovation Solution

A charging apparatus with an AC-DC converter, capacitor, DC-DC conversion unit, and electronic control unit that smoothes and adjusts output current based on detected voltage and frequency fluctuations, ensuring continuous charging by reducing output current when power quality deteriorates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the charger uses a capacitor to smooth DC electric power converted from AC, then the charging system works stably under normal conditions, but charging stops when external power supply voltage drops or frequency decreases

Engineering Contradiction:
Improvecharging continuityVSAvoidadaptability to external power fluctuations
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The charging system dynamically adjusts the charging current based on the quality of external power supply. The control unit monitors voltage and frequency, and modifies the charging current accordingly - reducing it when power quality deteriorates and maintaining normal levels when power supply is stable, thus adapting to varying external conditions while ensuring continuous charging

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the charging current parameter in response to changes in external power supply parameters (voltage and frequency). When voltage drops below a threshold or frequency decreases, the control unit reduces the charging current to prevent capacitor voltage collapse, allowing charging to continue under degraded power conditions

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the charger stops charging when capacitor voltage drops, then charging stability is maintained, but the vehicle cannot travel scheduled distance and emergency power supply is compromised

Engineering Contradiction:
Improvecharging stabilityVSAvoidvehicle travel distance
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

Instead of stopping charging when power quality deteriorates, the system dynamically adjusts the charging current to match the degraded power supply conditions. This dynamic response allows charging to continue at reduced rates, accumulating energy over time and ensuring the vehicle has sufficient range for scheduled travel and emergency power supply needs

Inventive Principle:
Principle #15Dynamics

3Reliability

If the charging current is reduced when external power state deteriorates, then charging can continue under unstable power, but the charging rate decreases

Engineering Contradiction:
Improvecharging continuityVSAvoidcharging speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system accepts partial charging action (reduced charging current) when external power supply quality deteriorates. Rather than maintaining full charging speed and risking complete charging failure, it operates at a reduced rate that ensures continuous energy accumulation, prioritizing charging continuity over charging speed

Inventive Principle:
Principle #16Partial or excessive 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

The system maintains continuous charging and power supply to the vehicle's electric power storage device and auxiliary load even with unstable external power, preventing unexpected travel distance reductions and auxiliary load failures.

Implementation Method 1

an AC-DC converter configured to convert AC electric power received from the charging port into DC electric power

Methodology Applied
Scientific EffectAC-DC conversion: Electromagnetic Induction

Implementation Method 2

a capacitor configured to smooth the DC electric power converted by the AC-DC converter

Methodology Applied
Scientific EffectCapacitance smoothing: Capacitance

Implementation Method 3

a DC-DC conversion unit configured to convert a voltage of the capacitor and supply the voltage to at least one of an electric power storage device or an auxiliary load

Methodology Applied
Scientific EffectDC-DC conversion: Electromagnetic Induction

Data Source

PatentUS10005370B2Charging apparatus for vehicle
Publication Date: 2018.06.26 TOYOTA JIDOSHA KK

AI summary

A charging apparatus is for a vehicle and the charging apparatus includes a charging port, an AC-DC converter, a capacitor, a DC-DC conversion unit and an electronic control unit. The electronic control unit is configured to reduce an output current from the DC-DC conversion unit to at least one of the electric power storage device or the auxiliary load in response to a deterioration from a predetermined state of a state of the electric power supplied from the outside of the vehicle to the charging port.