DFIG Wind Turbine Phase Angle Feedforward for Drivetrain Load Mitigation
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Solution Overview
Problem
Existing GFM DFIG-based wind turbine generators face challenges in optimizing mechanical stability due to insufficient drivetrain damping, leading to torque fluctuations and delayed active power response, which affects system safety and reliability, especially under weak grid conditions, and existing control methods fail to simultaneously enhance both active power response speed and GFM capability.
Innovation Solution
A method and system for drivetrain load mitigation using phase angle feedforward control, which involves acquiring active power, calculating differences, integrating with a virtual synchronous coordinate system, and controlling the converter's switching state to adjust the rotor excitation current, thereby transferring fault energy and mitigating drivetrain load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If virtual damping control is applied to enhance drivetrain damping, then drivetrain stability is improved, but active power response speed is significantly delayed
Solution Approach 1:
The patent applies preliminary action by predicting future drivetrain torque fluctuations using a observer before they occur, and preemptively adjusting the active power reference. This allows the system to counteract disturbances before they cause damage, eliminating the need for delayed virtual damping control while maintaining drivetrain stability and preserving fast response characteristics.
Solution Approach 2:
The patent implements feedback through a drivetrain torque observer that continuously monitors and predicts torque fluctuations, feeding this information back to the active power reference adjustment mechanism. This closed-loop feedback enables real-time compensation for drivetrain disturbances, achieving both stability enhancement and fast response by acting on predicted rather than delayed measurements.
2Reliability
If existing GFM control technologies are used to improve grid connection characteristics, then grid support capability is enhanced, but drivetrain mechanical stability is neglected
Solution Approach 1:
The patent merges grid-forming control with drivetrain load mitigation by integrating the torque observer and active power reference adjustment mechanism into the existing GFM control architecture. This combination allows the system to simultaneously provide grid support functions and protect drivetrain mechanical stability through coordinated control actions on the active power reference.
Solution Approach 2:
The patent achieves multi-functionality by designing a control mechanism that simultaneously performs grid-forming operations and drivetrain protection. The active power reference adjustment based on observer predictions serves dual purposes: maintaining GFM capability for grid support while concurrently mitigating drivetrain torque fluctuations, eliminating the need for separate control systems.
3Productivity
If active power output is increased to improve power generation efficiency, then energy conversion is enhanced, but drivetrain torque fluctuations increase
Solution Approach 1:
The patent extracts the harmful torque fluctuation component from the active power output by using the torque observer to identify and separate drivetrain-induced fluctuations from legitimate power generation variations. The control system then selectively adjusts only the fluctuation portion of the active power reference, preserving beneficial high power generation while eliminating harmful torque variations transmitted to the drivetrain.
Data Source
AI summary
A method for drivetrain load mitigation of grid-forming (GFM) doubly-fed induction generator (DFIG)-based wind turbine generator (WTG) based on phase angle feedforward, wherein: acquiring active power of a GFM DFIG-based WTG; calculating difference value between acquired active power of GFM DFIG-based WTG and active power reference value; inputting difference value into GFM control to obtain output signal; adding output signal and reference frequency value of virtual synchronous coordinate system to obtain frequency of virtual synchronous coordinate system; integrating the frequency to obtain output value; multiplying additional damping active power reference value of GFM DFIG-based WTG by control gain of phase angle feedforward control to obtain product result; adding product result and output value to obtain angle of virtual synchronous coordinate system, and based on the angle, obtaining control quantity for generator output voltage phase; based on control quantity, adjusting phase of actual output voltage of GFM DFIG-based WTG by controlling rotor excitation current.