Power Converter Overload Management via Periodic Cooling
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Solution Overview
Problem
Power converters are limited by their nominal power rating, which restricts their ability to handle short-term power surges beyond the nominal power without risking overheating and damage to semiconductor devices.
Innovation Solution
A method that allows power converters to operate at overload power for a specific period followed by a resting period at or below nominal power, using a control scheme to limit power and prevent overheating, with the power reduction occurring according to a predetermined time characteristic to avoid sudden changes and maintain safe operating temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the power converter operates at overload power beyond nominal power, then the power output capability is improved, but the temperature of semiconductor devices increases risking overheating and damage
Solution Approach 1:
The patent implements periodic action by alternating between overload operation periods and cooling periods. The converter operates at overload power for a defined time period to meet high power demands, then switches to a cooling period where power is reduced or stopped to allow semiconductor devices to cool down. This periodic cycling enables the system to deliver peak power when needed while preventing continuous overheating, thus resolving the contradiction between power output capability and temperature control.
Solution Approach 2:
The patent applies dynamics by making the power converter's operation dynamic rather than static. The control system continuously monitors temperature and dynamically adjusts the power output level based on real-time thermal conditions. The converter can switch between different operating states (overload, nominal, cooling) depending on the current temperature and thermal history, enabling adaptive power management that resolves the contradiction between maintaining high power capability and preventing overheating.
2Temperature
If the power is reduced suddenly from overload to nominal power, then the temperature control is improved, but the load experiences abrupt power changes causing operational issues
Solution Approach 1:
The patent applies preliminary action by preparing for power reduction in advance. Before abruptly reducing power from overload to nominal level, the control system activates a ramp-down function that gradually reduces power over a predefined time period. This preliminary gradual reduction prevents sudden power changes that could destabilize the load, while still achieving the ultimate goal of temperature control by reducing power from overload levels.
Solution Approach 2:
The patent implements parameter changes by smoothly transitioning the power parameter from overload level to nominal level through a controlled ramp-down process. Instead of making an abrupt step change in power output, the system varies the power parameter continuously over time according to a predefined ramp-down characteristic, thereby maintaining power stability for the load while achieving temperature control.
3Productivity
If the converter allows unlimited overload operation, then the productivity is improved, but the reliability of semiconductor devices deteriorates due to repeated thermal stress
Solution Approach 1:
The patent implements feedback by continuously monitoring the temperature of semiconductor devices and using this information to control the duration and frequency of overload operation periods. The control system adjusts the overload operation schedule based on thermal feedback, ensuring that overload periods are followed by sufficient cooling periods. This feedback mechanism allows the system to maintain high productivity through overload capability while preserving reliability by preventing excessive thermal stress accumulation.
Solution Approach 2:
The patent applies beforehand cushioning by built-in thermal management that cushions against thermal stress damage before it can occur. The system proactively schedules cooling periods and limits continuous overload duration based on predicted thermal accumulation, cushioning the semiconductor devices against the harmful effects of repeated thermal stress. This preventive approach allows the system to utilize overload capability for productivity while protecting reliability through advance thermal protection.
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 the operation of electrical appliances with power consumption exceeding nominal power by allowing stepwise power reduction from overload to nominal levels, effectively extending the operational range of power converters while ensuring semiconductor device safety through controlled temperature management.
Implementation Method 1
the nominal power of a semiconductor device is usually defined as a power which, when supplied, causes the temperature within the semiconductor device to not exceed the temperature limit
Data Source
AI summary
Method for operating a converter (3) to supply electricalpower to a load (2), comprising the steps of: -controlling the converter (3) for a provided overload time, so that overload power is applied to the load (2); and -controlling the converter (3) for a provided resting time, so that resting power is applied to the load (2); wherein the overload power is higher than a nominal power which corresponds to a steady-state operation limit of the converter (3), wherein the resting power is lower than the nominal power.