Multiport Converter Topology for Isolated Auxiliary Battery Supply

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Solution Overview

Problem

Conventional auxiliary power supply architectures for heavy-duty electric vehicles (HD EVs) are costly, heavy, and voluminous due to the use of independent isolated and non-isolated DC-DC converter modules, which are not integrated effectively with the main powertrain.

Innovation Solution

A multiport converter (MPC) system that integrates interleaved DC-DC converter circuitry with isolation transformers, sharing components with the main powertrain to provide power to 12 V and 24 V battery buses through interleaved auxiliary power-supply circuitry, reducing the number of components and maintaining isolation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If independent isolated DC-DC converter modules are used for auxiliary power supply, then reliability of power supply to auxiliary batteries is improved, but weight and volume of the powertrain increase

Engineering Contradiction:

Improvereliability of power supply to auxiliary batteriesVSAvoidweight of powertrain

Core Design Contradiction:

ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent combines the auxiliary power supply function with the existing DC-DC converter in the main powertrain, creating an integrated multiport converter that serves both the main powertrain and auxiliary battery systems. This merging eliminates the need for separate independent DC-DC converter modules, thereby reducing weight while maintaining the isolation and reliability required for auxiliary power supply.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If independent isolated DC-DC converter modules are used for auxiliary power supply, then reliability of power supply to auxiliary batteries is improved, but volume of the powertrain increases

Engineering Contradiction:

Improvereliability of power supply to auxiliary batteriesVSAvoidvolume of powertrain

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The auxiliary power supply circuitry is integrated into the existing DC-DC converter structure, sharing magnetic components and semiconductor devices. This consolidation significantly reduces the volume occupied by separate converter modules while preserving the isolation requirements for reliable auxiliary battery charging.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The DC-DC converter is designed with multi-functionality to serve both the main powertrain and auxiliary battery systems simultaneously. By making the converter universal, the patent eliminates the need for dedicated separate modules, thereby reducing overall powertrain volume while maintaining reliability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If independent isolated DC-DC converter modules are used for auxiliary power supply, then isolation between main powertrain and auxiliary batteries is maintained, but cost of the powertrain increases

Engineering Contradiction:

Improveisolation between main powertrain and auxiliary batteriesVSAvoidcost of powertrain

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the isolation function into a single integrated multiport converter design rather than requiring separate isolated converter modules. This approach reduces the total number of isolation components needed while maintaining the required electrical isolation between the main powertrain and auxiliary battery systems, thereby lowering overall cost.

Inventive Principle:

Principle #5Merging (Combining)

4Reliability

If multiple independent converter modules are used, then power supply to multiple auxiliary batteries is reliable, but device complexity increases

Engineering Contradiction:

Improvepower supply to auxiliary batteriesVSAvoidcomplexity of converter system

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple converter functions into a single integrated multiport converter with unified control circuitry. This consolidation reduces device complexity by eliminating the need for multiple independent control systems while maintaining reliable power supply to both 12V and 24V auxiliary battery systems through shared magnetic and semiconductor components.

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 MPC system reduces weight, volume, and cost while ensuring reliable power supply to auxiliary batteries, preserving the performance of the overall powertrain by sharing power electronic components with the main powertrain.

Implementation Method 1

first auxiliary power-supply circuitry including a first isolation transformer and fifth and sixth phase legs, where the fifth and sixth phase legs may be electrically coupled to respective mid-points of the first and third phase legs through the first isolation transformer

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS20250368058A1Multiport converter for auxiliary power supply

Publication Date: 2025.12.04 UT BATTELLE LLC

AI summary

Auxiliary converters may be integrated with a main DC-DC converter through a multiport converter (MPC) so that electronic components of the main DC-DC converter can be shared with the auxiliary converters, enabling reduction in volume, weight, and cost.