Vehicle Backup Power Switching to Prevent Inrush Voltage Drop

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Solution Overview

Problem

Inrush currents from multiple loads in a vehicle's backup power supply can overlap, causing a momentary voltage drop due to parasitic resistance, which hinders the operation of the backup power supply.

Innovation Solution

A power supply control device that switches between two modes to ensure only one load receives power from the backup source at a time, preventing overlapping inrush currents by controlling the power supply to the door unlock and brake systems based on vehicle states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If backup power supply is provided to multiple loads simultaneously, then the backup power supply can support more functions, but inrush currents overlap causing momentary voltage drop that hinders operation

Engineering Contradiction:

Improvebackup power supply capabilityVSAvoidoperation reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The backup power supply is segmented into multiple independent power supply units, each dedicated to a specific load. The switching unit selectively connects only the required power supply unit to the main line based on which load needs power, preventing simultaneous operation of multiple loads and avoiding inrush current overlap.

Inventive Principle:

Principle #1Segmentation

2Reliability

If capacitor capacity is increased to prevent voltage drop, then voltage stability improves, but device complexity and cost increase

Engineering Contradiction:

Improvevoltage stabilityVSAvoidcapacitor capacity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system dynamically switches between different power supply units based on real-time load requirements. The switching unit responds to power failure conditions by selectively activating only the necessary power supply unit, adapting the system's power supply configuration to match actual needs rather than providing static over-capacity support.

Inventive Principle:

Principle #15Dynamics

3Reliability

If switching unit is added to control power supply modes, then inrush current overlap is prevented, but device complexity increases

Engineering Contradiction:

Improveinrush current controlVSAvoidswitching unit structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The switching unit acts as an intermediary component that mediates between the multiple power supply units and the main power line. It selectively connects or disconnects power supply units based on operational requirements, providing intelligent control without requiring complex capacitor configurations or system redesign.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12187208B2Power supply control device, control method, and storage medium

Publication Date: 2025.01.07 TOYOTA JIDOSHA KK

AI summary

Provided is a power supply control device for a vehicle. The power supply control device is a device that controls power supply to a plurality of loads from a second power supply source provided for backup of a first power supply source. The power supply control device includes: a switching unit that switches between a first mode in which power of the second power supply source is supplied to a first load and not supplied to a second load, and a second mode in which the power of the second power supply source is supplied to the second load and not supplied to the first load; and a control unit that controls mode switching of the switching unit based on a state of the vehicle.