UPS Synchronization via Common Reference Angle
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Solution Overview
Problem
In power systems with multiple uninterruptible power supplies (UPSs), synchronization issues can lead to oscillations and interference, causing instability and impacting load sharing when one UPS becomes disconnected from the utility, as the common reference angle may drift, affecting the stability and efficiency of power delivery.
Innovation Solution
A controller determines a common reference angle and calculates phase angles for each UPS relative to this angle, ensuring synchronized operation and stable power sharing among UPSs, even when the utility is disconnected from one or more of them, using a processor and memory device to execute instructions for load sharing algorithms and droop control techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple separate UPSs are used to provide redundant power supply, then power reliability is improved, but synchronization stability deteriorates due to reference angle drift and interference between power sources
Solution Approach 1:
The patent merges multiple separate UPS power sources into a coordinated system by implementing a common reference angle mechanism. All UPS units synchronize their output phases to this common reference, preventing interference and oscillations while maintaining redundant power supply capability. This combining approach allows multiple independent power sources to work together as a unified system.
Solution Approach 2:
The system implements feedback control by continuously monitoring the reference angle and adjusting each UPS output phase accordingly. When utility disconnection occurs, the common reference angle is maintained through feedback from synchronized UPS units, preventing reference angle drift and ensuring stable load sharing among all UPS units in the system.
2Adaptability or versatility
If separate UPSs operate independently with their own reference angles, then operational independence is improved, but load sharing performance deteriorates due to phase angle drift and oscillations
Solution Approach 1:
The common reference angle mechanism serves multiple functions simultaneously: it provides a universal synchronization standard for all UPS units, enables automatic load sharing coordination, and maintains system stability during utility disconnections. This universal reference allows each UPS to operate independently while contributing to collective system performance.
3Stability of the object's composition
If UPSs are synchronized to a common reference angle, then load sharing stability is improved, but system complexity increases due to coordination requirements
Solution Approach 1:
The common reference angle acts as an intermediary that simplifies the coordination between multiple UPS units. Instead of requiring complex direct communication and synchronization protocols between each pair of UPS units, the system uses this intermediate reference angle as a common coordination point, reducing control complexity while maintaining stability.
Data Source
AI summary
A system is provided. The system includes a utility, a plurality of uninterruptible power supplies (UPSs), a ring bus, at least one load electrically coupled to the plurality of UPSs and the ring bus, and a controller communicatively coupled to the plurality of UPSs, the controller configured to determine a common reference angle while the utility is disconnected from at least one UPS of the plurality of UPSs, calculate a phase angle for each UPS of the plurality of UPSs, wherein the phase angle for each UPS is calculated relative to the common reference angle, and control operation of each UPS based on the respective calculated phase angles.