Semiconductor Chip Temperature Estimation via Voltage Drop
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Solution Overview
Problem
Existing methods for estimating the temperature of semiconductor chips in power semiconductor devices are limited, particularly during operation, and often rely on current measurements, which do not effectively account for wear and thermal stress, leading to inaccurate temperature assessment and potential device degradation.
Innovation Solution
A method that determines the voltage drop over the semiconductor chip during operation using a measuring circuit and evaluates this voltage drop in relation to the applied load current based on a temperature model established when the device is not in operation, allowing for accurate temperature estimation and compensation for wear over the device's lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current measurements are used to estimate temperature, then the measurement process is simple, but the temperature assessment accuracy deteriorates due to not accounting for wear and thermal stress
Solution Approach 1:
The patent applies preliminary action by establishing the temperature model and determining model parameters during the manufacturing process or initial calibration phase, before the device enters operation. This includes performing voltage drop measurements at known temperatures to establish the relationship between voltage drop, current, and temperature. By doing this preparation work in advance, the system achieves accurate temperature assessment during operation without requiring complex real-time calculations or additional sensors.
Solution Approach 2:
The patent uses voltage drop as an intermediary parameter to indirectly measure temperature. Instead of directly measuring temperature or using current alone, the system measures voltage drop across the semiconductor chip, which serves as a mediator that reflects both current and temperature effects. This intermediary measurement approach enables accurate temperature assessment while keeping the measurement process relatively simple.
2Reliability
If temperature estimation is performed during operation, then real-time temperature monitoring is achieved, but the ability to establish accurate model parameters deteriorates due to unknown thermal conditions
Solution Approach 1:
The patent resolves this contradiction by performing the parameter establishment action preliminarily, during manufacturing or initial calibration when the device is not yet in operation. This preliminary parameter establishment ensures accurate model parameters are obtained under controlled conditions, while the model itself can then be used for reliable real-time temperature monitoring during operation.
Solution Approach 2:
The system uses feedback by continuously monitoring voltage drop and current during operation, then using these measurements with the pre-established temperature model to estimate temperature in real-time. The feedback loop allows the system to maintain reliable temperature monitoring throughout the device's operational life, utilizing the accurately established model parameters.
3Productivity
If current limit is used to protect the power device, then the protection method is simple, but the chip area utilization deteriorates due to conservative limiting
Solution Approach 1:
The patent replaces the mechanical/current-based protection system with a temperature-based protection system. Instead of using fixed current limits that conservatively protect the device, the system uses temperature estimation based on voltage drop measurements to dynamically determine safe operating conditions. This substitution allows for better chip area utilization while maintaining reliable protection, as temperature is the actual limiting factor for semiconductor devices.
Solution Approach 2:
The patent changes the protection parameter from current to temperature. By monitoring temperature through voltage drop measurements and using the temperature model, the system can adjust operating parameters based on actual thermal conditions rather than fixed current limits. This parameter change enables more efficient utilization of chip capacity while ensuring protection against thermal degradation.
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
This approach enables precise temperature estimation and monitoring of semiconductor chips, enabling better utilization, extended lifespan, and improved reliability by using temperature as a limiting factor instead of current, and allowing for more efficient operation and overload detection.
Implementation Method 1
determining a voltage drop over the semiconductor chip for a value of applied load current
Implementation Method 2
When exerting a power device to a current, the chip will heat due to the internal losses in the chip
Data Source
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Figure 5(a)~6(b)
AI summary
The invention regards a method for estimating the temperature of a semiconductor chip accommodated in a power semiconductor device in operation, such as an IGBT power module, the method comprising the steps of; while the power semiconductor device is in operation determining a voltage drop over the power semiconductor device for a value of applied load current and; estimating the temperature of the semiconductor chip by evaluating the relationship between the determined voltage drop and the value of applied load current on the basis of a semiconductor chip temperature model. The invention also regards the corresponding apparatus for estimating the temperature of a semiconductor chip, as well as a wind turbine comprising such an apparatus.