Static Transfer Switch Flux Control for Inrush Current

Solution Overview

Problem

Conventional static transfer switches face issues such as high inrush current, prolonged transfer times, and limited compatibility with different transformer types, which can damage equipment and disrupt power supplies.

Innovation Solution

A static transfer switch system utilizing three digital signal processor circuits to detect power quality events and compute real-time flux balancing, allowing seamless switching between preferred and alternate power sources, minimizing inrush current and transfer time while ensuring compatibility with various transformer types.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional static transfer switches are used to toggle between power sources, then power source switching can be achieved, but high inrush current is produced that can damage electrical equipment

Engineering Contradiction:

Improveequipment protectionVSAvoidinrush current

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The system performs preliminary flux balancing computation before the transfer operation. The third digital signal processor circuit computes the required flux adjustment and pre-synchronizes the switching timing to occur at the optimal point in the AC cycle, thereby preventing high inrush current from occurring during the transfer.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors the actual flux conditions during the transfer process using digital signal processors. Based on real-time feedback from the measured voltages and computed flux values, the system dynamically adjusts the switching timing to maintain flux balance and minimize inrush current throughout the transfer operation.

Inventive Principle:

Principle #23Feedback

2Reliability

If conventional static transfer switches are used for power source toggling, then transfer function is provided, but transfer time exceeds the tolerance of critical loads

Engineering Contradiction:

Improvepower supply continuityVSAvoidtransfer time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary flux balancing computation before the transfer operation. The third digital signal processor circuit computes the required flux adjustment and pre-synchronizes the switching timing to occur at the optimal point in the AC cycle, thereby preventing high inrush current from occurring during the transfer.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors the actual flux conditions during the transfer process using digital signal processors. Based on real-time feedback from the measured voltages and computed flux values, the system dynamically adjusts the switching timing to maintain flux balance and minimize inrush current throughout the transfer operation.

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If conventional static transfer switches are used, then basic transfer function is achieved, but performance degrades when used with transformer types other than the specific configured transformer

Engineering Contradiction:

Improvetransformer compatibilityVSAvoidtransfer performance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The system uses digital signal processors to dynamically compute flux balancing parameters based on real-time voltage measurements rather than relying on fixed hardware configurations. This software-based approach allows the same circuit to adapt to different transformer types (delta-wye, wye-delta, delta-delta, wye-wye) by computing the appropriate flux balance equations for each configuration.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system changes the computational parameters (flux balancing equations and switching timing) based on the detected transformer configuration. The digital signal processors adjust the flux computation algorithms and switching angles according to the specific transformer type being used, thereby maintaining optimal performance across different transformer configurations.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11050250B2Static transfer switch system with real time flux control

Publication Date: 2021.06.29 ABB (SCHWEIZ) AG

AI summary

A static transfer switch assembly includes a first digital signal processor circuit associated with a preferred power source to detect a power quality event at the preferred power source, and a second digital signal processor circuit associated with an alternate power source to detect a power quality event at the alternate power source. A third digital signal processor circuit is in communication with each of the first and second digital signal processors and with a transfer switch. The third digital signal processor circuit computes and balances flux in real time based on sample voltages received from each of the preferred and alternate power sources, and controls the transfer switch to transfer the load from one of the power sources to the other power source, based on one of the first or second digital signal processor circuits detecting a power quality event.