Low-Voltage On-Board Electrical System Load Control
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Solution Overview
Problem
Conventional on-board electrical systems of motor vehicles face voltage fluctuations due to dynamic consumers, leading to excessive load on the low-voltage system, which can result in system failure, especially during high-demand situations like engine starting or battery discharge.
Innovation Solution
A method for controlling a low-voltage on-board electrical system that identifies when a high-current consumer is connected and reduces the current consumption of another consumer by an equivalent amount, using pulse width modulation to adjust the power consumption of consumers like cooling fans, thereby alleviating load peaks and preventing system overloading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple complex components (DC/DC converters, adjustable diodes) are used to prevent voltage fluctuations, then voltage stability is improved, but device complexity increases
Solution Approach 1:
The patent extracts and removes complex voltage regulation components (DC/DC converters, adjustable diodes) from the system. Instead of using multiple complex components to prevent voltage fluctuations, the invention isolates the problematic dynamic consumers and excludes them from the low-voltage network during critical operations, thereby simplifying the system while maintaining voltage stability.
Solution Approach 2:
The patent segments the consumer group into dynamic consumers and static consumers, and further divides operation modes into critical operations and non-critical operations. By controlling which segment operates during which mode, the system achieves voltage stability without requiring complex voltage regulation components.
2Power
If DC/DC voltage converter performance limits are exceeded during high load, then power is drawn from the low-voltage battery, but this leads to higher load due to increased cyclization and potential system failure
Solution Approach 1:
The patent performs preliminary action by detecting the start of a critical operation (engine starting, battery charging) before the high load occurs. Upon detection, the control device proactively isolates dynamic consumers from the low-voltage network, preventing the load peak from occurring in the first place. This avoids exceeding DC/DC converter limits and prevents battery over-discharge.
Solution Approach 2:
The patent applies preliminary anti-action by preemptively counteracting the harmful effect of high load through consumer isolation. Before the high load from dynamic consumers can stress the DC/DC converter and battery, the system anticipates the critical operation and removes the dynamic consumers from the circuit, thereby preventing the harmful load condition.
3Reliability
If dynamic consumers are isolated during critical operations, then voltage fluctuations are prevented, but consumer availability decreases
Solution Approach 1:
The patent implements dynamic control where the availability of dynamic consumers is adjusted based on system conditions. During critical operations, dynamic consumers are isolated to ensure voltage stability. During non-critical operations, they are reconnected to provide full functionality. This dynamic adaptation resolves the contradiction between reliability and ease of operation.
Solution Approach 2:
The patent changes the operational parameter of consumer availability based on the detected operation mode. The control device transitions dynamic consumers between connected and isolated states depending on whether the system is in a critical or non-critical operation mode, thereby optimizing both voltage stability and consumer availability.
Data Source
AI summary
A method for controlling consumers of a low-voltage on-board electrical system of a motor vehicle reduces, when it is identified that a high-current consumer is connected, the current consumption of another consumer by an amount that corresponds to the current consumption of the high-current consumer. A control apparatus for controlling consumers of a low-voltage on-board electrical system of a motor vehicle is also provided.