Source Inverter Overlap-Free Power Transfer Timing
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Solution Overview
Problem
Existing methods for transferring electric power supply from a faulty source to a backup source in industrial settings, such as those involving high-power motors, often result in significant disruptions due to phase and frequency deviations, and previous solutions either cause overintensities or are costly and inefficient.
Innovation Solution
A method and device that utilize two switches to transfer the power supply without overlapping, where delay times are computed to ensure a predetermined transfer duration of between 10 ms and 50 ms, minimizing disruptions by synchronizing the disconnection of the faulty source with the connection of the backup source, using average operation durations of the switches to optimize the timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If fast switches are used to transfer sources in minimum time, then transfer speed is improved, but switch cost increases significantly and overintensities may occur due to not accounting for opening and closing times
Solution Approach 1:
The patent applies preliminary action by computing delay times before commanding the switches to operate. The source inverter calculates the exact timing for opening the first switch and closing the second switch based on predetermined transfer duration, ensuring the switches are commanded at the optimal moment to avoid overintensities while using standard switches rather than expensive fast switches.
2Reliability
If the transfer duration is extended to allow transient phenomena to subside, then motor disruptions are reduced, but the transfer time increases and motors may slow down too much
Solution Approach 1:
The patent applies parameter changes by optimizing the transfer duration to a specific range of 10-50 milliseconds. This predetermined duration is calculated to be sufficient for transient phenomena to subside while being short enough to prevent excessive motor slowdown, thus balancing reliability and time loss through precise parameter selection.
3Adaptability or versatility
If phase deviation up to 90° is allowed during transfer, then transfer flexibility is improved, but significant disruptions occur in high-power motor operation
Solution Approach 1:
The patent applies feedback by using a source inverter to actively synchronize the phase and frequency of the backup source with the main source before transfer. The source inverter monitors and adjusts the backup source parameters in real-time, ensuring phase alignment within acceptable limits during the transfer process, thus preventing motor disruptions while maintaining transfer capability.
Data Source
AI summary
The invention relates to a method for transferring, during a predetermined transfer duration, the electric power supply of an electric distribution line (7) from a first source (1) to a second source (2), without overlapping of the two sources.The invention also relates to a source inverter implementing such a method.