Hybrid Vehicle Battery Charging Voltage Conversion Control

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Solution Overview

Problem

Hybrid vehicles face inefficiencies in charging from external sources due to heat generation and energy loss, which affects overall energy efficiency during home charging.

Innovation Solution

A vehicle configuration with first and second chargeable power storage devices, voltage conversion devices, and a control system that manages charging by rectifying operations and balancing state of charge between devices to minimize losses, using chopper circuits and a control device to optimize voltage conversion and charging efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single power storage device is charged from an external source, then the charging system is simple, but heat generation and energy loss increase, reducing charging efficiency

Engineering Contradiction:
Improvecharging system complexityVSAvoidcharging energy loss
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The power storage system is divided into multiple independent power storage devices (first power storage device and second power storage device), each with its own voltage conversion device. This segmentation allows the charging current to be distributed across multiple devices, reducing heat generation and energy loss in any single device while improving overall charging efficiency.

Inventive Principle:
Principle #1Segmentation

2Loss of energy

If multiple power storage devices are charged simultaneously, then charging efficiency improves, but the voltage balance between devices becomes difficult to maintain

Engineering Contradiction:
Improvecharging energy lossVSAvoidvoltage balance between devices
Core Design Contradiction:
Loss of energyVSStability of the object's composition

Solution Approach 1:

The control device continuously monitors the voltage levels of both power storage devices and dynamically adjusts the operation of the voltage conversion devices. Based on feedback regarding the state of charge and voltage levels, the control device optimizes charging parameters to maintain voltage balance between devices while maximizing charging efficiency.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The voltage conversion devices operate in a dynamic manner, with their conversion ratios and power distribution continuously adjusted based on real-time conditions. This dynamic operation allows the system to adapt to changing voltage levels and maintain balance between devices throughout the charging process.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If voltage conversion is performed during charging, then compatibility with external power sources improves, but additional energy loss occurs in the conversion process

Engineering Contradiction:
Improvecompatibility with external power sourcesVSAvoidvoltage conversion loss
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The voltage conversion function is merged with the power management function in an integrated control system. The voltage conversion devices are coordinated with the charging control to perform conversion only when necessary, and the system optimizes the conversion process by leveraging the existing voltage levels of power storage devices, thereby reducing redundant conversion operations and associated energy losses.

Inventive Principle:
Principle #5Merging (Combining)

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 solution enables efficient charging with reduced energy loss, maintaining balanced state of charge between power storage devices and optimizing power usage for hybrid vehicles.

Implementation Method 1

the control device causes the first voltage conversion device to perform a rectifying operation for supplying an electric current from the charging line to the electric power line

Methodology Applied
Scientific EffectRectifying operation: Diode

Implementation Method 2

the first and second voltage conversion devices each include a chopper circuit having an upper arm where a switching element and a rectifying element are connected in parallel

Methodology Applied
Scientific EffectChopper circuit switching: Electromagnetic Induction

Data Source

PatentEP2169801B1vehicle
Publication Date: 2018.08.22 TOYOTA JIDOSHA KK
  • EP2169801B1 patent drawingFigure 1
  • EP2169801B1 patent drawingFigure 2
  • EP2169801B1 patent drawingFigure 3~4

AI summary

A vehicle (1) includes a plurality of chargeable and dischargeable batteries (B1, B2), a load device, a bus for supplying electric power to the load device, a plurality of voltage step-up converters (12-1, 12-2) provided in association with a plurality of batteries (B1, B2) respectively, a charging line (PCL) for supplying electric power provided from outside the vehicle to a connection point of the first battery (B1) and the first voltage step-up converter (12-1), and a control device (30). When charging from an external source is started, the control device (30) causes the first voltage step-up converter (12-1) to perform a rectifying operation for supplying electric current from the charging line to the bus in a case where a voltage of the bus is lower than a voltage of the charging line, and causes the first voltage step-up converter (12-2) to connect the bus and the second battery (B2).