Wind Turbine Current Controller Harmonic Injection
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Solution Overview
Problem
Wind turbines, particularly those with direct drive generators, face challenges in reducing acoustic noise and vibration due to air-gap torque ripple and radial force pressure ripple, as existing solutions either require complex control methods or limited design modifications that compromise performance.
Innovation Solution
A current controller within the generator-side converter controller of a wind turbine's frequency converter injects harmonic currents to minimize torque and radial force pressure ripples, using a harmonic current reference calculation unit and controller to generate converter control signals that reduce noise and vibration, with the harmonic current error minimized in a stationary alpha-beta frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If harmonic current injection control method is used to reduce acoustic noise and vibration, then acoustic noise and vibration are reduced, but control complexity increases due to need for fundamental current commands and separate regulation of positive and negative sequence components
Solution Approach 1:
The patent extracts only the necessary harmonic current regulation functionality from the conventional control system. Instead of implementing full fundamental current commands and separate positive/negative sequence regulations, the invention selectively applies harmonic current injection only where needed to cancel torque ripple and radial force pressure ripple, thereby reducing acoustic noise and vibration while minimizing control complexity
Solution Approach 2:
The patent inverts the conventional control approach by not starting from fundamental current commands and deriving harmonic components, but rather directly calculating the required harmonic current references based on detected torque ripple and radial force pressure ripple characteristics. This reverse engineering approach simplifies the control structure by eliminating unnecessary intermediate steps
2Object-affected harmful factors
If multiple input signals including fundamental current commands are used for harmonic current control, then noise and vibration reduction is achieved, but the number of required signals and processing steps increases
Solution Approach 1:
The patent extracts only the essential input signals needed for harmonic current control, eliminating the requirement for fundamental current commands and separate positive/negative sequence components. The control system uses only the necessary signals to calculate harmonic current references and implement noise reduction, thereby reducing the number of processing steps
Data Source
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AI summary
The invention relates to a wind turbine which comprises an electric generator (11), a frequency converter (12) and a generator-side converter controller (20). The generator-side converter controller (20) comprises a current controller (30) which is configured such that a harmonic current error (Ialphanerr, Ibetanerr), which is defined by the difference between feedback generator current signals (Ialpha, Ibeta) and a harmonic current reference (Ialphanref, Ibetanref), is minimized. Thus, acoustic noise and vibration of the electric generator (11) may be reduced. Advantageously, the harmonic current error (Ialphanerr, Ibetanerr) is determined in a stationary frame, in particular a stationary alpha-beta frame.