Backflow preventing means, power conversion apparatus, and freezing air conditioning apparatus
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Solution Overview
Problem
The challenge lies in reducing recovery electric current losses in power converting devices, particularly when using high current-carrying elements, which are costly and prone to crystal defects, making it difficult to achieve efficiency in handling high power levels, such as those required for air-conditioning compressor motors.
Innovation Solution
Incorporating a backflow preventing element connected between the power supply and load, along with commutating means that redirect electric current to a different path, thereby reducing recovery electric current through commutation operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high current-carrying capacity elements are used in backflow preventing means, then the permissible effective electric-current value increases, but the cost increases and crystal defects occur
Solution Approach 1:
The invention divides the current path into two segments: a first path through the backflow preventing element for normal operation, and a second path through the commutating means for recovery current diversion. This segmentation allows the backflow preventing element to operate at lower current levels, reducing the need for expensive high-current elements while maintaining system reliability.
Solution Approach 2:
The commutating means acts as an intermediary component that redirects recovery current away from the backflow preventing element. By introducing this intermediate current path, the system avoids subjecting the backflow preventing element to high recovery currents, thereby reducing manufacturing costs and crystal defect risks while maintaining adequate current-carrying capacity for normal operation.
2Loss of energy
If recovery electric current is reduced through commutation, then conduction loss decreases, but device complexity increases due to additional commutating means
Solution Approach 1:
The invention merges the commutating means with the existing backflow preventing element structure, where the commutating means includes a commutation element connected in parallel with the backflow preventing element. This merging approach allows the system to reduce conduction losses through current commutation while minimizing the increase in device complexity by integrating the commutation function into the existing circuit topology.
3Reliability
If commutating means is added to redirect current, then recovery electric current is reduced, but device complexity increases
Solution Approach 1:
The commutating means introduces dynamic current path switching capability to the system. The commutation element can dynamically redirect recovery current based on operating conditions, enabling the system to adaptively optimize efficiency by bypassing the backflow preventing element during recovery events while maintaining a relatively simple overall circuit structure through controlled dynamic operation.
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3~4
AI summary
For example, backflow preventing means is provided, which reduces a recovery electric current occurring in the event of backflow of an electric current so as to ensure high efficiency, high reliability, etc. The backflow preventing means includes a backflow preventing element, such as a rectifying element 3a, which is connected between an alternating-current power supply 1 and a load 6 and prevents the electric current from flowing backward from the load 6 toward the alternating-current power supply 1; and commutating means 7 for performing a commutation operation for causing the electric current to flow toward a different path that is connected in parallel with the backflow preventing element, whereby a conduction loss and a loss caused by the electric current can be reduced.