Series Battery-Capacitor Drive Circuit for Multi-Voltage Vehicles

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Solution Overview

Problem

Existing vehicle control circuits require additional power storage devices with higher voltages to supply higher voltage power, leading to increased vehicle weight and cost.

Innovation Solution

A vehicle drive system that connects a battery and a capacitor in series, with a control circuit managing electrical switches and coils to charge and discharge energy between them, allowing for multiple power supply voltages with a simple configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If another power storage device with higher voltage is adopted to supply higher voltage power, then the power supply capability is improved, but the vehicle weight increases

Engineering Contradiction:
Improvepower supply voltageVSAvoidvehicle weight
Core Design Contradiction:
PowerVSWeight of moving object

Solution Approach 1:

The patent combines a capacitor and battery in series to create a hybrid power supply system. The capacitor provides high voltage during peak power demands while the battery supplies sustained power, achieving higher voltage output without adding separate high-voltage power storage devices that would increase weight.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The series connection configuration allows the same capacitor-battery assembly to provide multiple voltage levels (capacitor voltage, battery voltage, and combined voltage) to different electrical loads. This multi-functionality eliminates the need for separate power storage devices for different voltage requirements, reducing overall system weight.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Power

If another power storage device with higher voltage is adopted to supply higher voltage power, then the power supply capability is improved, but the cost increases

Engineering Contradiction:
Improvepower supply voltageVSAvoidmanufacturing cost
Core Design Contradiction:
PowerVSEase of manufacture

Solution Approach 1:

The patent merges a capacitor and battery into a single hybrid power supply unit that delivers higher voltage. This approach is more cost-effective than purchasing and installing separate high-voltage power storage devices, as it utilizes existing lower-voltage components in a creative configuration.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The series-connected capacitor-battery system serves multiple voltage supply functions simultaneously, replacing what would otherwise require multiple separate power storage devices. This consolidation reduces component count, simplifies manufacturing, and lowers overall system cost.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Device complexity

If a series connection of capacitor and battery is used, then the configuration simplicity is improved, but the control complexity increases

Engineering Contradiction:
Improvepower supply configurationVSAvoidcharging control automation
Core Design Contradiction:
Device complexityVSExtent of automation

Solution Approach 1:

The charging circuit automatically detects the charging state of the capacitor and battery, and autonomously controls the switching between charging modes. The system self-regulates the charging process without requiring manual intervention, managing the increased control complexity through automated feedback mechanisms.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The control circuit continuously monitors the voltages and charging states of both the capacitor and battery, using this feedback information to dynamically adjust switching operations. This feedback mechanism enables the system to manage the complex charging control requirements while maintaining operational simplicity.

Inventive Principle:
Principle #23Feedback

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 configuration provides a lightweight and cost-effective means to supply multiple power supply voltages, enabling efficient charging and discharging of the battery and capacitor, while maintaining input voltage above a lower limit, thus supporting vehicle travel with reduced weight and cost.

Implementation Method 1

a capacitor (22) having a rated voltage higher than a rated voltage of the battery (18)

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

a battery (18) and a capacitor (22) connected in series

Methodology Applied
Scientific EffectBattery (electricity): Battery (electricity)

Implementation Method 3

a first coil (19a) and a second coil (19b) magnetically coupled to each other

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3748807B1Vehicle drive system comprising a series connection of capacitor and battery and a vehicle
Publication Date: 2024.01.17 MAZDA MOTOR CORP
  • EP3748807B1 patent drawingFigure 1
  • EP3748807B1 patent drawingFigure 2
  • EP3748807B1 patent drawingFigure 3

AI summary

A vehicle drive system 10 includes: a power supply 3 in which a battery 18 and a capacitor 22 are connected in series; a primary drive motor 16 to which a voltage of the battery 18 is provided; secondary drive motors 20 to each of which a total voltage (Vin) of the battery 18 and the power supply capacitor 22 is provided; a charging circuit 19; and a control circuit 24 that controls charging/discharging of the power supply 3. The control circuit 24 operates switches SW1, SW2 of the charging circuit 19 so as to control charging/discharging of the battery 18 and the capacitor 22.