Motor Vehicle Circuit Voltage Control via Inversion

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Solution Overview

Problem

Existing vehicle circuit control methods face challenges in efficiently managing voltage drops across multiple consumers, particularly in preventing control oscillations and ensuring safety-critical components receive adequate voltage while non-safety-critical consumers reduce current consumption within a short timeframe without requiring costly components.

Innovation Solution

A method and control device for an open-loop system that determines when the vehicle circuit voltage drops below a threshold, rapidly lowers the voltage at non-safety-critical consumers, and then raises it at a controlled rate to prevent voltage drops, using a voltage controller and scanning units to manage current flow and maintain system stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the voltage at non-safety-critical consumers is gradually lowered to reduce current consumption, then the current draw is reduced, but control oscillations may occur and the response time may exceed the predefined timeframe

Engineering Contradiction:

Improvecurrent consumptionVSAvoidcontrol stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

Instead of gradually lowering the voltage to reduce current consumption, the patent inverts the approach by abruptly lowering the voltage to a minimum value (near zero) and then continuously raising it at a predetermined rate. This reversal of the control direction prevents control oscillations while achieving the same current reduction goal within the predefined timeframe.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent implements dynamic voltage control by continuously adjusting the voltage at the consumer based on the vehicle circuit voltage status. The voltage is raised at a predetermined rate of change rather than being statically set, allowing the system to adapt to changing conditions and prevent oscillations while maintaining reliable current management.

Inventive Principle:

Principle #15Dynamics

2Speed

If the voltage at the consumer is rapidly lowered to relieve the vehicle circuit, then the current is reduced quickly, but the consumer functionality may be adversely affected

Engineering Contradiction:

Improveresponse timeVSAvoidconsumer operation

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent implements periodic voltage adjustment: the voltage is abruptly lowered to a minimum value, then continuously raised at a predetermined rate, and this cycle repeats based on vehicle circuit voltage conditions. This periodic action pattern ensures rapid response when needed while allowing the consumer to recover functionality when the vehicle circuit voltage is sufficient.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent applies preliminary action by detecting the vehicle circuit voltage status in advance and proactively adjusting the consumer voltage before critical undervoltage conditions occur. The control device continuously monitors and preemptively lowers voltage when thresholds are approached, preventing both oscillations and consumer damage.

Inventive Principle:

Principle #10Preliminary action

3Use of energy by moving object

If multiple consumers are controlled by an open-loop system to reduce current, then the overall current consumption is reduced, but control oscillations can occur that load the vehicle circuit voltage

Engineering Contradiction:

Improvecurrent consumptionVSAvoidcontrol oscillations

Core Design Contradiction:

Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent inverts the conventional control approach by continuously raising voltage from a minimum value rather than continuously lowering it. This reversal of the control direction eliminates the feedback loop that causes oscillations in traditional gradual reduction methods, while still achieving current consumption reduction within the required timeframe.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent employs a simple, cost-effective open-loop control mechanism that sacrifices continuous consumer functionality temporarily (short-living operation at reduced voltage) to eliminate complex feedback control systems. The consumer is briefly operated at minimum voltage to relieve the circuit, then gradually restored, avoiding the need for expensive oscillation-prevention hardware.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Data Source

PatentUS11377052B2Control of an electric circuit in a motor vehicle

Publication Date: 2022.07.05 ZF FRIEDRICHSHAFEN AG

AI summary

A method (200) for operating an electrical vehicle circuit (115) of a motor vehicle (105) includes determining that a voltage of the vehicle circuit (115) drops below a predetermined threshold value while electric current from the vehicle circuit (115) flows through a consumer (130) on board the motor vehicle (105), lowering a voltage present at the consumer (130) in order to reduce the current flowing through the consumer (130), and successively raising the voltage present at the consumer (130).