EV Power Bus Diode Layout for Balanced Auxiliary Loads

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Solution Overview

Problem

Existing power-supply systems for electric and hybrid vehicles face challenges in balancing the charge states of multiple storage units, leading to inefficiencies and potential breakdowns due to unbalanced power demands among electric motors and auxiliary loads.

Innovation Solution

A power-supply system with three separate storage units connected by diodes that allow direct current flow from the motor units to auxiliary loads while inhibiting reverse current flow, ensuring automatic charge balancing and redundancy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single DC-link is used to handle power for both auxiliary loads and electric motors, then the system structure is simplified, but the charge states of storage units become unbalanced leading to inefficiencies and potential breakdowns

Engineering Contradiction:
Improvesystem structureVSAvoidcharge state balance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent divides the single DC-link system into multiple separate DC-links, with each storage unit connected to its own dedicated DC-link. This segmentation allows independent power management for each storage unit while maintaining overall system functionality, thereby preventing charge state imbalance without significantly increasing system complexity.

Inventive Principle:
Principle #1Segmentation

2Reliability

If separate DC-links are used for each storage unit to balance charge states, then charge state balance is improved, but the system complexity and wiring increase

Engineering Contradiction:
Improvecharge state balanceVSAvoidwiring structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple DC-links into a modular architecture where each DC-link serves a specific storage unit but can interact with others through controlled power flow. This merging approach maintains the benefits of separate power management while reducing overall wiring complexity through standardized connection interfaces and power electronic converters that enable flexible power routing.

Inventive Principle:
Principle #5Merging (Combining)

3Object-affected harmful factors

If diodes are used to allow direct current flow from motor units to auxiliary loads while inhibiting reverse current flow, then short-circuit risks are reduced, but the device complexity increases

Engineering Contradiction:
Improveshort-circuit risksVSAvoidcomponent count
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent introduces diodes as intermediary components in the power flow paths between storage units, DC-links, and loads. These diodes act as one-way valves that permit current flow in the desired direction (from motor units to auxiliary loads) while blocking reverse current flow, thereby preventing short-circuits and protecting system components without requiring complex active switching devices.

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

The system optimizes wiring, reduces short-circuit risks, ensures continuous operation of auxiliary loads, and facilitates easy design with improved safety and redundancy by automatically balancing charge states among storage units.

Implementation Method 1

a third storage unit (28) connected to a third power supply line or bus (36) through a third set of fuses (46) and to the first and second power supply lines (32, 34) through diodes (40, 42)

Methodology Applied
Scientific EffectDiode rectification effect: Diode

Data Source

PatentEP4244089B1Power-supply system of electric motors and auxiliary electric loads for an electric vehicle, and electric vehicle
Publication Date: 2026.03.18 ALTRA SPA
  • EP4244089B1 patent drawingFigure 1~2
  • EP4244089B1 patent drawingFigure 3~4

AI summary

A power supply system (20, 50) for an electric or hybrid vehicle, comprising: a first storage unit (24) coupled to a first electric motor (22) via a first power-supply bus (32); a second storage unit (27) coupled to a second electric motor (25) via a second power-supply bus (34); a third storage unit (28) coupled to at least one auxiliary electrical load (30) via a third power-supply bus (36). The first power-supply bus (32) is connected to the third power-supply bus (36) through a first diode (40) designed to permit the sole current flow from the first power-supply bus (32) to the third power-supply bus (36), and the second power-supply bus (34) is connected to the third power-supply bus (36) through a second diode (42) designed to permit the sole current flow from the second power-supply bus (34) to the third power-supply bus (36).