Backflow preventing device, power conversion apparatus, and refrigerating and air-conditioning apparatus
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Solution Overview
Problem
The practical application of high-efficiency power conversion apparatuses using elements with large electric-current capacity is hindered by high costs and crystal defects, making it difficult to achieve increased efficiency, especially in systems like air-conditioning compressors.
Innovation Solution
A backflow preventing device is designed with a backflow preventing element and a commutating device configured as a module, which includes a commutation rectifying element with low current-carrying capacity, reducing size, heat-dissipation complexity, and costs by using elements like fast recovery diodes or wide-band gap semiconductors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If elements with large electric-current capacity are used in power conversion apparatus, then efficiency is improved, but cost increases and crystal defects occur
Solution Approach 1:
The power conversion apparatus is segmented into multiple functional modules: a backflow preventing element (first element) and a commutating device (second element) with commutation rectifying elements. This segmentation allows each element to be optimized for its specific function, enabling the use of low-current-capacity, high-reliability elements instead of requiring all elements to handle large currents.
Solution Approach 2:
The commutating device acts as an intermediary between the power supply and the load, providing an alternative current path during commutation. This intermediary structure allows the backflow preventing element to operate at lower current levels while maintaining system efficiency, thereby avoiding crystal defects associated with high-current elements.
2Loss of energy
If elements with large electric-current capacity are used, then efficiency is improved, but device size increases
Solution Approach 1:
By segmenting the power conversion apparatus into specialized modules with low-current-capacity elements, the overall device size is reduced compared to using single high-current elements throughout the system.
3Loss of energy
If elements with large electric-current capacity are used, then efficiency is improved, but heat-dissipation complexity increases
Solution Approach 1:
Segmenting the apparatus into modules with low-current elements reduces the heat generation at each component, simplifying the overall heat-dissipation design and reducing thermal management complexity.
4Loss of energy
If elements with large electric-current capacity are used, then efficiency is improved, but recovery electric current increases
Solution Approach 1:
The commutating device serves as an intermediary that provides a controlled current path during switching transitions. This intermediary structure enables precise control of recovery electric current, reducing harmful reverse recovery effects while maintaining efficient power conversion.
5Loss of energy
If elements with large electric-current capacity are used, then efficiency is improved, but noise increases
Solution Approach 1:
By segmenting the power conversion apparatus into specialized modules with low-current-capacity elements optimized for their specific functions, the patent reduces switching losses and electromagnetic interference, thereby decreasing noise while maintaining high efficiency.
Data Source
AI summary
A backflow preventing device includes a backflow preventing element that is connected between a power supply and a load and that prevents electric current from flowing backward from the load side toward the power supply side, and a commutating device that performs a commutation operation for causing the electric current to flow to a commutation path connected in parallel with the backflow preventing element. A plurality of elements including at least one or more of elements constituting the commutating device are configured as a module, so that, for example, the device can be reduced in size. Moreover, a simplified heat-dissipation design and a simplified air-duct design can be achieved.