Vehicle Charging System Dynamic Power Path Selection

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Solution Overview

Problem

Existing vehicle charging systems face inefficiencies when selecting between DC and AC power sources for charging, leading to suboptimal charging times and energy usage due to voltage variations and power supply limitations.

Innovation Solution

A vehicle system equipped with first and second power conversion devices and a control device that can utilize both DC and AC power sources for charging, selecting the most efficient power path based on the state of charge and capacity of the power storage device and the power supply, allowing for simultaneous or sequential use of both power sources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If charging is performed using AC power supply with high power generation efficiency, then energy loss is reduced, but charging time becomes excessively long

Engineering Contradiction:
Improveenergy lossVSAvoidcharging time
Core Design Contradiction:
Loss of energyVSLoss of time

Solution Approach 1:

The system dynamically switches between AC and DC power supply modes based on real-time conditions. The control device monitors the state of charge and automatically selects the optimal charging path, transitioning from static charging mode selection to dynamic adaptive switching, thereby resolving the contradiction between energy efficiency and charging speed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the operating parameters by introducing dual power supply paths with different characteristics. AC power supply operates at high efficiency for bulk charging, while DC power supply provides high speed charging capability. The control device adjusts charging parameters based on state of charge thresholds, optimizing the balance between energy loss and charging time.

Inventive Principle:
Principle #35Parameter changes

2Loss of time

If DC power supply with high speed charging capability is used, then charging time is reduced, but energy loss increases

Engineering Contradiction:
Improvecharging timeVSAvoidenergy loss
Core Design Contradiction:
Loss of timeVSLoss of energy

Solution Approach 1:

The system employs dynamic mode switching where the control device monitors state of charge and automatically transitions between DC and AC charging modes. This dynamic control ensures DC high-speed charging is used only when necessary (low state of charge), minimizing energy loss while achieving fast charging when time is critical.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention applies partial use of DC power supply capability - not continuously, but selectively based on state of charge thresholds. AC power supply handles the majority of charging (excessive action for efficiency), while DC provides supplemental high-speed charging when needed, optimizing the overall energy-time tradeoff.

Inventive Principle:
Principle #16Partial or excessive action

3Ease of operation

If the charging mode is selected at the beginning based on estimated charging time, then charging path is determined, but charging efficiency is not optimized due to voltage variation

Engineering Contradiction:
Improvecharging control simplicityVSAvoidcharging efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The control device implements feedback control by continuously monitoring the state of charge and charging conditions. Based on this feedback, the system automatically adjusts the charging path selection, switching between AC and DC modes as needed. This closed-loop control optimizes charging efficiency while maintaining operational simplicity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The charging system performs self-optimization through automatic mode switching based on real-time state of charge monitoring. The control device independently determines the optimal charging path without requiring manual intervention, adapting to voltage variations and power supply conditions autonomously, thereby maintaining ease of operation while maximizing charging efficiency.

Inventive Principle:
Principle #25Self-service

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 enables efficient charging by optimizing the use of both DC and AC power sources, reducing charging time and improving energy utilization, even when the power supply's capacity exceeds the rating of the DC charger.

Implementation Method 1

The first power conversion device converts the electric power from the DC power supply into charging electric power for the power storage device

Methodology Applied
Scientific EffectPower conversion:

Implementation Method 2

The second power conversion device converts electric power from the AC power supply into charging electric power for the power storage device

Methodology Applied
Scientific EffectPower conversion:

Data Source

PatentEP2716490B1vehicle
Publication Date: 2019.12.11 TOYOTA JIDOSHA KK
  • EP2716490B1 patent drawingFigure 1
  • EP2716490B1 patent drawingFigure 2
  • EP2716490B1 patent drawingFigure 3

AI summary

A vehicle (100) is capable of charging a power storage device (110) mounted thereon using electric power from two power paths of an external DC power supply (520) and AC power supply (510). The vehicle includes a DC charger (210) for converting electric power from the DC power supply (520) into charging electric power for the power storage device (110), and an AC charger (200) for converting electric power from the AC power supply (510) into charging electric power for the power storage device (110). A vehicle ECU (300) selects an electric power path to be used for charging based on the state of the power storage device (110) and efficiency of the DC charger (210) and the AC charger (200).