Switching Element Temperature Control in Electrical Power Converters
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Solution Overview
Problem
Existing electrical power converters face challenges in reducing switching loss when operating with only one of multiple electricity storage apparatuses, as the controlling methods disclosed in prior literature may not effectively cancel switching losses between storage apparatuses.
Innovation Solution
An electrical source control apparatus that selects and controls switching elements to minimize switching state changes, particularly by keeping one switching element in an ON state while changing the state of another, and adjusts based on temperature differences to prevent excessive heating, thereby reducing switching loss without current cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the electrical power converter operates with only one electricity storage apparatus, then the system can perform power conversion with a single storage apparatus, but the switching loss cannot be reduced through current cancellation between multiple storage apparatuses
Solution Approach 1:
The patent changes the switching pattern parameters by selectively keeping one switching element in ON state while changing others, and adjusting carrier wave phases dynamically based on operating conditions. This parameter adaptation allows the system to reduce switching loss in single-storage-apparatus mode by optimizing the switching timing and patterns, effectively resolving the contradiction between operational flexibility and energy loss.
2Productivity
If switching elements are frequently changed to perform power conversion, then the power conversion capability is improved, but the temperature difference between switching elements increases causing excessive heating
Solution Approach 1:
The patent implements periodic switching actions using carrier waves with specific phases. By controlling the switching elements in periodic cycles and maintaining at least one element in ON state, the system distributes the switching stress over time rather than concentrating it, thereby reducing temperature differences between elements while maintaining power conversion capability.
Solution Approach 2:
The patent proactively manages temperature by keeping at least one switching element in ON state as a cushioning measure. This element acts as a thermal buffer, preventing excessive temperature rise in other switching elements that undergo frequent switching. The temperature monitoring and adaptive control provide beforehand cushioning against thermal stress.
3Productivity
If the switching state of multiple switching elements is changed simultaneously, then the power conversion efficiency is improved, but the complexity of control increases
Solution Approach 1:
The patent segments the control of switching elements by treating them in groups - at least one element is controlled differently (kept in ON state) from the others. This segmentation simplifies the control logic by creating distinct control strategies for different elements, reducing overall control complexity while maintaining efficient power conversion through coordinated switching of the segmented groups.
Data Source
AI summary
An electrical source control apparatus has a selecting device for selecting one switching element from at least two switching elements each of which constitutes predetermined arm element whose switching state should be changed to perform the electrical power conversion, when the electrical power converter performs the electrical power conversion with either one of the first and the second electricity storage apparatuses; and a controlling device for controlling the electrical power converter to change a switching state of the selected one switching element while keeping a switching state of another one switching element in an ON state, the selecting device newly selects the one switching element to reduce a difference between temperatures of the at least two switching elements each of which constitutes predetermined arm element.