Vehicle Power Supply Isolation During Battery Voltage Drops

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Solution Overview

Problem

Vehicle batteries experience voltage drops during operation, causing capacitive reserves to discharge quickly, which can lead to errors or damage to the vehicle's calculation and control system, particularly during memory write operations.

Innovation Solution

A control device that isolates specific vehicle circuits from the energy storage element, using a transistor and detection means to manage power supply, preventing the discharge of the capacitive reserve and protecting transistors from operating in linear mode during voltage drops.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the capacitive reserve is used to compensate for battery voltage drops, then the vehicle circuits can continue to be powered, but the capacitive reserve discharges very quickly and may not have enough time to complete memory write operations

Engineering Contradiction:
Improvepower supply continuityVSAvoidmemory write operation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The invention segments the vehicle circuits into two groups: a first group of circuits that are isolated from the energy storage element during voltage drops, and a second group of circuits that remain connected. This segmentation allows the capacitive reserve to be dedicated exclusively to critical circuits (such as the computer processing unit) that require uninterrupted power for completing memory write operations, preventing the rapid discharge problem while ensuring reliability for time-critical operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention applies local quality by providing different power supply configurations to different circuits based on their specific requirements. Critical circuits that need to complete memory write operations are connected directly to the energy storage element with guaranteed power supply, while other circuits are isolated. This localized approach ensures that the capacitive reserve is concentrated on circuits where time is critical, rather than being diluted across all vehicle circuits.

Inventive Principle:
Principle #3Local quality

2Reliability

If the battery voltage drops, then the capacitive reserve discharges quickly, but this can force transistors to operate in linear mode which could damage them

Engineering Contradiction:
Improvetransistor protectionVSAvoidpower supply stability
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The invention extracts the first circuit (containing transistors vulnerable to damage) from the connection with the energy storage element during voltage drops. By using a switching element to open the connection between the energy storage element and the first circuit, the transistors are protected from operating in linear mode under voltage drop conditions. This extraction eliminates the harmful interaction while maintaining power supply stability for protected circuits through alternative power paths.

Inventive Principle:
Principle #2Taking out (Extraction)

3Adaptability or versatility

If the energy storage element is connected to all vehicle circuits, then all circuits can be powered during voltage drops, but this causes rapid discharge and insufficient time for critical operations

Engineering Contradiction:
Improvepower supply coverageVSAvoidmemory write operation completion
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The invention segments the circuit connections to the energy storage element, creating a selective power distribution system. A switching element controlled by voltage detection means segments the connection for the first circuit during voltage drops, while maintaining connections for other circuits. This segmentation achieves adaptability by providing power coverage where needed (isolating non-critical circuits) while preserving productivity for critical operations (ensuring dedicated power for memory write operations).

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention implements preliminary action through voltage detection means that detect voltage drops before they cause damage or operational failure. Upon detection, the control means activates switching elements to reconfigure the circuit connections in advance, isolating vulnerable circuits and dedicating the capacitive reserve to critical operations. This preliminary reconfiguration prevents the harmful effects of rapid discharge and ensures sufficient time for memory write operations to complete.

Inventive Principle:
Principle #10Preliminary action

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

Ensures sufficient power supply to critical circuits, such as the computer processing unit, allowing it to complete memory write operations without errors and reducing the risk of transistor damage by isolating them from the capacitive reserve during voltage drops.

Implementation Method 1

said control means are configured to, in the event of detection of a drop in the battery voltage below said threshold value, control the blocked state of the first transistor

Methodology Applied
Scientific EffectTransistor blocking:

Implementation Method 2

the vehicle includes a capacitive reserve, i.e., a reserve of electrical energy stored by one or more capacitive elements such as a capacitor or a supercapacitor

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3271993B1Device for controlling the electrical power supply of a circuit for a vehicle, comprising a battery and corresponding assembly
Publication Date: 2025.01.22 VALEO SYST THERMIQUES SAS
  • EP3271993B1 patent drawingFigure 1

AI summary

The invention relates to a device for controlling the electrical power supply of a circuit for a vehicle, said vehicle comprising: an electrical battery (2); an electrical energy storage element (C1), one terminal of which is connected to the first terminal (VBAT) of the battery and the other terminal of which is connected to an electrical earth; a first circuit (5), capable of consuming electricity coming from the electrical battery (2), and having first and second terminals respectively connected to the first and second terminals (-VBAT, VBAT) of the battery (2); and electrical supply management means (Q1) configured to allow or prevent the passage of electrical current between said electrical energy storage element (C1) and said first circuit (5). Said control device comprises detection means (41) configured to detect a drop in voltage of the battery (2) below a threshold value, and command means (42) configured, in the event of detection of a drop in voltage of the battery below said threshold value, to command said electrical supply management means (Q1) in order to prevent the passage of electrical current between the electrical energy storage element (C1) and said first circuit (5).