UPS Bypass Snubber Layout for Back-Feed Voltage Suppression
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Solution Overview
Problem
During power failures, back-feed voltage can be generated in uninterruptible power supply apparatuses, which can cause surges and require snubber circuits to reduce these surges.
Innovation Solution
The proposed solution involves an uninterruptible power supply apparatus with a feed compensation circuit and a bypass circuit that includes first to third switches and corresponding snubber circuits, which are connected in a specific configuration to reduce back-feed voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a snubber circuit is added to reduce surges during switch operation, then surge reduction is improved, but back-feed voltage is generated during power failure
Solution Approach 1:
The snubber circuit is divided into two separate circuits: a first snubber circuit connected between the switch and the load, and a second snubber circuit connected between the first snubber circuit and the power supply. This segmentation isolates the back-feed voltage generation point from the surge protection function, allowing the second snubber circuit to suppress back-feed voltage while the first snubber circuit continues to reduce surges during switch operation.
Solution Approach 2:
The first snubber circuit acts as an intermediary element between the switch and the second snubber circuit. It provides a controlled path for voltage during switch operation, allowing the second snubber circuit to effectively suppress back-feed voltage without compromising the surge reduction capability of the overall snubber system.
2Reliability
If the bypass circuit is connected in parallel with the inverter circuit, then power supply reliability is improved, but back-feed voltage is generated during power failure
Solution Approach 1:
The snubber protection is segmented into two circuits: the first snubber circuit maintains the bypass circuit's ability to provide reliable power supply during failures, while the second snubber circuit specifically addresses back-feed voltage suppression. This segmentation allows the bypass circuit to maintain its reliability function without generating harmful back-feed voltage.
Data Source
AI summary
An uninterruptible power supply apparatus includes a feed compensation circuit and a bypass circuit. The bypass circuit is provided in electrically parallel with the feed compensation circuit. The bypass circuit includes first to third switches and first to third circuits. The first to third switches are connected respectively to the first to third phases of a three-phase AC load. The first to third circuits are provided in electrically parallel with the first to third switches, respectively. The first circuit includes a first snubber circuit, a second snubber circuit, and a power line. The second circuit includes a first snubber circuit, a second snubber circuit, and a power line. The third circuit includes a first snubber circuit, a second snubber circuit, and a power line. Respective power lines of the first to third circuits are electrically connected to each other.