Parallel DC Converter Cooling Diagnosis for Sensor Fault Detection
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Solution Overview
Problem
In motor vehicle DC/DC converters with parallel converter strands, existing methods fail to reliably diagnose temperature sensor functionality due to differing power losses and temperatures across strands, leading to potential overheating and safety risks.
Innovation Solution
A method that captures input voltage, output voltage, and operating current for each strand, determines instantaneous temperatures, calculates coolant temperatures using a temperature model, and compares these to diagnose sensor functionality, switching to emergency operation if a fault is detected, with a control unit managing the cooling device to ensure safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If temperature sensors are assigned to each converter strand for monitoring, then overheating protection is improved, but reliable diagnosis of sensor functionality deteriorates due to different power losses and temperatures in individual strands
Solution Approach 1:
The patent introduces coolant temperature as an intermediary reference value to diagnose temperature sensor functionality. Instead of directly comparing temperatures from different converter strands (which have different power losses), the system uses the coolant temperature measured by a separate coolant temperature sensor as a common reference point. This intermediary allows indirect verification of temperature sensor accuracy without being affected by the different operating conditions of individual strands.
Solution Approach 2:
The system uses the coolant cooling system and its temperature sensor to serve the dual purpose of both cooling the converter strands and providing a reference for diagnosing the temperature sensors. The coolant temperature sensor, which is part of the cooling system, becomes a self-service component that simultaneously performs cooling monitoring and temperature sensor diagnostics.
2Adaptability or versatility
If converter strands are operated with different powers to meet varying power requirements, then system versatility is improved, but temperature uniformity between strands deteriorates
Solution Approach 1:
The patent applies local quality by assigning individual temperature sensors to each converter strand, allowing each strand to be monitored independently according to its specific thermal conditions. This enables the system to accommodate different power levels in each strand while maintaining appropriate temperature monitoring and protection for each local region.
3Device complexity
If a single cooling device serves both converter strands, then device complexity is reduced, but temperature monitoring precision deteriorates
Solution Approach 1:
The coolant serves multiple functions: it cools both converter strands and acts as a thermal medium for diagnosing temperature sensor functionality. The single cooling device is designed to be universal, serving both converter strands while the coolant temperature measurement provides diagnostic information for both strands indirectly.
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
Enables reliable temperature sensor diagnosis and prevents overheating by identifying malfunctions, ensuring safe operation of the voltage converter and maintaining driving safety by deactivating the affected strand in emergency mode.
Implementation Method 1
Heat loss is produced during operation of the voltage converter and results in heating of the electrical components of the converter strands themselves... a cooling device which carries a coolant and is assigned to the converter strands, wherein a coolant which is used to remove the heat loss produced
Implementation Method 2
at least one temperature sensor for capturing a converter temperature in each case is assigned to each of the converter strands
Implementation Method 3
a coolant temperature is determined for each converter strand on the basis of the values captured in steps a) and b)... the coolant temperature can be calculated in a simple manner on the basis of the values mentioned by using a temperature model
Data Source
AI summary
The invention relates to a device for operating a voltage converter (1), in particular a DC converter, of a motor vehicle, which voltage converter has at least two parallel-connected converter strands (4, 5) which are connected between a high-voltage side (2) and a low voltage side (3) of the voltage converter (1) for converting the voltage, having at least one cooling device (8) carrying a coolant (9) and assigned to the converter strands (4, 5), wherein each of the converter strands (4, 5) is assigned at least one temperature sensor (6, 7), comprising the following steps: a) detecting an input voltage, an output voltage and an operating current of each converter strand (4, 5), b) detecting a current converter strand temperature by means of the respective temperature sensor (6, 7), c) determining a respective coolant temperature as a function of the values detected in steps a) and b), d) comparing the two determined coolant temperatures (T_1, T_2) with each other and e) determining the serviceability of the temperature sensors (6, 7) on the basis of the result of the comparison.