Semiconductor Switching Element Thermal Stress Management
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Solution Overview
Problem
Semiconductor switching elements in high-power AC power generation devices for industrial processes, such as induction heating and plasma systems, face premature failure due to thermal expansion stresses and temperature gradients, leading to mechanical stress and reduced reliability, especially when operated in pulsed power modes.
Innovation Solution
A method that alternates power output and pulse pause periods to manage power losses in semiconductor switching elements, increasing power loss during pulse pauses to minimize temperature differences and reduce mechanical stress, thereby extending the service life of these elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If semiconductor switching elements are operated in pulsed power mode with high power output, then productivity and power generation capability are improved, but thermal expansion stresses and temperature gradients cause mechanical stress leading to premature failure
Solution Approach 1:
The patent applies periodic action by introducing a pause period between power output periods. During these pause periods, the semiconductor switching elements are not subjected to high power stress, allowing thermal equilibrium to be achieved. This periodic on-off operation pattern prevents continuous thermal cycling that causes mechanical stress and failure, thereby extending the service life while maintaining productivity during the power output periods.
Solution Approach 2:
The patent implements preliminary action by allowing the semiconductor switching elements to cool down during pause periods before the next power output period begins. This preliminary cooling action prevents the accumulation of thermal stress and avoids exceeding maximum temperature thresholds, ensuring reliable operation when high power is needed again.
2Temperature
If cooling is applied to semiconductor switching elements during operation, then temperature control is improved, but temperature gradients create additional mechanical stresses
Solution Approach 1:
The patent extracts the cooling action from continuous operation and applies it only during pause periods when no power is being output. By removing the cooling load during high-power operation, the patent avoids creating temperature gradients and mechanical stresses that would result from active cooling during operation, while still maintaining adequate temperature control during the pause periods.
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 reduces the failure rate of semiconductor switching elements by managing power losses and temperature fluctuations, enhancing reliability and cost-effectiveness, while allowing for continued reduction of power loss, thus improving the operational stability of high-power AC power generation devices.
Implementation Method 1
a first power loss PV1 during the power output period ΔT1 and a second power loss PV2 during the pulse pause period ΔT2 are generated in the at least one semiconductor switching element, and the generated power losses PV1, PV2 are converted into heat
Implementation Method 2
the different thermal expansion coefficients of the materials used in the semiconductor switching elements (e.g.: substrate, semiconductor layer, bonding wires). Even if all parts of the semiconductor switching element were to heat up to the same temperature at the same time, the different thermal expansion of the materials causes internal mechanical stresses
Implementation Method 3
When generating power of more than 100W using semiconductor switching elements, it is usually essential to force-cool the semiconductor switching elements, e.g. using heat sinks with forced air flow or liquid cooling
Data Source
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AI summary
The invention relates to a method for operating a plasma system, an induction heating system, or a laser excitation system in a pulsed power output mode, wherein a first power POUT1,1 is generated in a power output time period ?T1, and is output at a power output of a power generator for providing power to a plasma process, of an induction heating process, or of a laser excitation process, and no power Pout2,1 suitable for igniting or operating a plasma process, an induction process, or a laser excitation process is output at the power output of the power generator in a pulse pause time period ?T2, in that at least one semiconductor circuit element (9) of the power generator is actuated, wherein a first loss power PV1 is generated in the at least one semiconductor circuit element (9) at the same time as the generation of the first power Pout1,1 during the power output time period ?T1, and a second loss power PV2 is generated in the at least one semiconductor element (9) during the pulse pause time period ?T2, and the generated loss powers PV1, Pv2 are converted into heat, wherein a drop in temperature of the semiconductor circuit element (9) by greater than a predefined value is prevented by suitably actuating the semiconductor circuit element, and the power output mode and pulse pause mode alternate continuously.