DC-Link Capacitor Temperature Estimation via Microprocessor Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing temperature estimation methods for components in power electronics of electric vehicles are computationally complex and lack sufficient accuracy without direct temperature sensors on critical components like the DC link capacitor.
Innovation Solution
A simplified temperature estimation model using an internal temperature sensor on a microprocessor within the inverter, combined with an electro-thermal model, allows for accurate estimation of the DC link capacitor temperature by integrating measurements from the microprocessor and operational parameters, reducing the need for additional direct sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing temperature estimation methods are used, then temperature estimation is achieved, but computational complexity is high
Solution Approach 1:
The patent uses the microprocessor temperature sensor as an intermediary measurement point to indirectly estimate the DC link capacitor temperature. Instead of directly measuring the capacitor temperature (which would require additional sensors and computation), the method uses the microprocessor temperature as a proxy that correlates with capacitor temperature through a simplified thermal model, reducing computational burden while maintaining estimation accuracy.
Solution Approach 2:
The patent creates a simplified thermal model that copies the essential thermal behavior of the power electronics system without requiring complete physical characterization. The model uses the microprocessor temperature reading to represent the thermal state of the entire system, allowing temperature estimation without complex direct measurements of all components.
2Measurement precision
If direct temperature sensors are added to critical components, then measurement accuracy improves, but device complexity and cost increase
Solution Approach 1:
The patent makes the existing microprocessor temperature sensor serve multiple functions: it not only monitors the microprocessor's own temperature for processor protection but also serves as the primary measurement input for estimating the temperature of other critical components like the DC link capacitor. This multi-functional use eliminates the need for additional dedicated temperature sensors on those components.
Solution Approach 2:
The microprocessor's internal temperature sensor, designed for self-monitoring purposes, is leveraged to also monitor the thermal state of other system components. The system uses its own existing sensor resource to serve additional measurement needs without requiring external assistance or additional hardware investments.
3Productivity
If simplified models are used, then computational burden is reduced, but estimation accuracy may deteriorate
Solution Approach 1:
The patent applies a partial thermal model that captures only the essential thermal relationships needed for accurate estimation, rather than implementing a complete physics-based thermal model of all system components. This partial modeling approach focuses computational resources on the most critical thermal pathways (microprocessor to DC link capacitor) while ignoring less significant thermal effects, achieving sufficient accuracy with reduced computation.
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
The method provides accurate temperature estimation with reduced computational burden, enabling effective thermal management and preventing component failure by using a simplified model that maintains high precision.
Implementation Method 1
The microprocessor has a temperature sensor mounted directly thereto; the temperature sensor being configured to sense a temperature of the microprocessor
Implementation Method 2
A simplified temperature estimation model using an internal temperature sensor on a microprocessor within the inverter, combined with an electro-thermal model
Data Source
AI summary
Temperature of a DC link capacitor coupled to power electronics of an electric vehicle is estimated without a temperature sensor being mounted directly to the DC link capacitor. The power electronics include a microprocessor with a temperature sensor, such as internal to the microprocessor. The power electronics and DC link capacitor are modeled as a simplified electro-thermal model in which all the power electronics, other than the microprocessor are modeled as a single element. State space equations derived from the electro-thermal model are evaluated to obtain an estimated temperature of the DC link capacitor for a given time step.