Bidirectional DC/DC Converter Layout for Multi-Output Battery Charging

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Solution Overview

Problem

Conventional isolated AC/DC converters require a large installation space for switches with increased power loss due to switch operation when charging multiple loads.

Innovation Solution

A power conversion device with a bidirectional DC/DC converter connected between two DC outputs of multiple converter units, allowing power transmission based on required power and controlling output power using an average value calculation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a switch matrix is used to distribute power to multiple outputs, then power distribution flexibility is improved, but installation space and power loss increase

Engineering Contradiction:

Improvepower distribution flexibilityVSAvoidinstallation space

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

Multiple converter units are merged into a single integrated system with a common DC bus, eliminating the need for separate switch matrices for each output. The bidirectional DC/DC converter consolidates power distribution control, reducing the overall footprint while maintaining the ability to serve multiple outputs simultaneously.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The bidirectional DC/DC converter serves multiple functions: it acts as a power distribution controller, a load balancer, and a voltage regulator simultaneously. This multi-functional approach replaces what would traditionally require multiple separate components including switch matrices, reducing installation space while maintaining adaptability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If a switch matrix is used to distribute power to multiple outputs, then power distribution flexibility is improved, but power loss increases

Engineering Contradiction:

Improvepower distribution flexibilityVSAvoidpower loss

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The control unit continuously monitors the power requirements of each output and dynamically adjusts the bidirectional DC/DC converter operation accordingly. This feedback mechanism ensures power is distributed efficiently to match actual demand, minimizing losses while maintaining the flexibility to adapt to different loading conditions.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system transitions from a static switch matrix configuration to a dynamic power distribution approach where the bidirectional DC/DC converter continuously adapts its operation based on real-time power demands. This dynamic control optimizes power flow paths and reduces resistive losses compared to fixed switch matrix arrangements.

Inventive Principle:

Principle #15Dynamics

3Adaptability or versatility

If multiple converter units are used to meet varying power demands, then adaptability to different power requirements is improved, but device complexity increases

Engineering Contradiction:

Improveadaptability to power demandsVSAvoiddevice complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system is segmented into multiple independent converter units, each capable of operating autonomously. This modular segmentation allows the system to scale adaptively by activating only the necessary number of units based on power demand, managing complexity through standardized modular components rather than a single complex system.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The bidirectional DC/DC converter acts as an intermediary between multiple converter units and the final outputs. This mediator component simplifies the overall system architecture by providing a single point of control and power distribution, reducing the complexity that would otherwise arise from direct interconnections between multiple converter units and multiple outputs.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Enables charging multiple storage devices efficiently without switches, reducing power loss and accommodating different charging speeds for multiple loads.

Implementation Method 1

a bidirectional DC/DC converter connected between two DC outputs of a plurality of DC outputs of the plurality of converter units. The bidirectional DC/DC converter transmits at least a part of output power of the converter unit at one DC output from the one DC output to the other DC output

Methodology Applied

Scientific EffectElectrical energy transmission: Conduction (electrical)

Data Source

PatentUS12620913B2Power conversion device including a plurality of converter units and a bidirectional DC/DC converter connected between two dc outputs of a plurality of dc outputs of the plurality of converter units

Publication Date: 2026.05.05 HITACHI LTD

AI summary

A power conversion device charges a plurality of storage devices and includes a plurality of converter units that receives AC power and outputs DC power, and a bidirectional DC/DC converter connected between two DC outputs of a plurality of DC outputs of the plurality of converter units. The bidirectional DC/DC converter transmits at least a part of output power of the converter unit at one DC output from the one DC output to the other DC output of the two DC outputs according to required power of the plurality of storage devices.