Rotor Winding Torque Control for Turbomachinery Oscillation Damping
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Solution Overview
Problem
Turbomachinery systems experience sub-synchronous torsional interactions (SSTIs) due to complex interactions between electrical machine harmonic oscillations and torsional dynamics, leading to increased maintenance costs, reduced operational efficiency, and equipment service life, with existing mitigation methods being complex, expensive, and difficult to integrate into existing systems without shutting down operations.
Innovation Solution
The implementation of an electrical machine with a rotor winding that alternately energizes and de-energizes to apply and remove corrective torque, detected by sensors, to dampen harmonic and torsional oscillations, reducing SSTIs and torque imbalances, and allowing for easier integration and maintenance without system shutdowns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If known SSTI and torque mitigation devices and systems are implemented, then torque imbalances and oscillations are reduced, but device complexity and system modification requirements increase
Solution Approach 1:
The patent extracts the mitigation function from complex external devices and implements it within the electrical machine's existing rotor winding structure. By utilizing the rotor winding as the corrective element, the system eliminates the need for separate mitigation devices and reduces overall system complexity while maintaining torque balance improvement.
Solution Approach 2:
The rotor winding serves multiple functions: it performs the primary electrical function of the motor/generator while simultaneously acting as the SSTI mitigation device. This multi-functionality eliminates the need for dedicated mitigation hardware, reducing device complexity while maintaining reliability improvements.
2Reliability
If elaborate control systems are used for SSTI mitigation, then oscillation damping improves, but ease of operation and integration difficulty worsen
Solution Approach 1:
The control function is merged with the existing electrical machine control system. The rotor winding control is integrated into the standard motor control architecture, eliminating the need for separate elaborate control systems. This integration maintains effective oscillation damping while significantly improving ease of operation and reducing integration complexity.
3Ease of manufacture
If complete plant shutdown is required for installation and maintenance, then system modification can be performed, but loss of time and productivity decrease
Solution Approach 1:
The mitigation system utilizes the existing rotor winding infrastructure that is already part of the electrical machine. Since the corrective elements are integrated into the existing motor/generator structure, installation and maintenance can be performed during normal operations without requiring complete plant shutdown, thereby maintaining productivity while enabling system modification.
4Reliability
If substantial modification of existing systems is performed, then SSTI mitigation effectiveness improves, but ease of manufacture and cost increase
Solution Approach 1:
The patent extracts the mitigation function from external system modifications and implements it within the existing rotor winding. This approach achieves effective SSTI mitigation without requiring substantial modification of the electrical machine or associated systems, thereby improving ease of manufacture and reducing implementation costs while maintaining mitigation effectiveness.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively reduces SSTIs, aberrant torques, and torque imbalances, lowering maintenance and operating costs while enhancing operational efficiency and simplifying the integration of SSTI mitigation systems into existing turbomachinery systems without requiring complete shutdowns.
Implementation Method 1
The at least one rotor winding is configured to alternately energize and de-energize to alternately apply and remove, respectively, a corrective torque to the electrical machine to dampen harmonic oscillations
Data Source
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AI summary
A turbomachinery system includes a turbomachine, a shaft, a rotor power converter, and an electrical machine. The electrical machine is coupled to the turbomachine by the shaft extending therebetween. The electrical machine includes a stator defining a cavity therein, and a rotor coupled to the shaft, where the rotor and the shaft are positioned at least partially within the cavity. The rotor includes at least one rotor winding coupled to the rotor power converter. The at least one rotor winding is configured to alternately energize and de-energize to alternately apply and remove, respectively, a corrective torque to the electrical machine to dampen harmonic oscillations of the turbomachinery system.