Gearless Wind Turbine Generator Torque Ripple Control
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Solution Overview
Problem
Gearless wind turbines generate noise due to torque ripple and vibrations, which limits their placement near settlements and increases installation challenges due to noise perception on the ground despite being at high altitudes.
Innovation Solution
A method for controlling the synchronous generator of a gearless wind turbine using a six-phase system with a controlled rectifier, which reduces torque ripple by shaping the stator current to be sinusoidal and compensating for harmonics, employing a state observer to accurately control the rotor flux and magnetic field, and utilizing a Kalman filter to account for stochastic disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a synchronous generator with high pole count is used in a gearless wind turbine, then the generator can directly drive the aerodynamic rotor at low speed (5-15 rpm), but the generator produces significant noise and vibrations due to torque ripple
Solution Approach 1:
The patent applies parameter changes by modifying the current waveform parameters through active control. The rectifier actively shapes the stator current to be sinusoidal and controls its magnitude and phase, thereby changing the operational parameters to minimize torque ripple and reduce noise vibrations while maintaining the low-speed direct-drive configuration
Solution Approach 2:
The patent implements feedback control through a state observer that estimates rotor flux and stator current in real-time. The controller uses this feedback information to continuously adjust the rectifier switching signals, ensuring optimal current waveforms that minimize torque ripple and associated noise vibrations during generator operation
2Object-generated harmful factors
If the stator current is controlled to be sinusoidal with harmonic compensation, then torque ripple is reduced and noise is minimized, but the device complexity increases due to the need for state observer and Kalman filter
Solution Approach 1:
The patent introduces a state observer as an intermediary component that indirectly estimates rotor flux and stator current without requiring direct measurement of these quantities. This intermediary estimation mechanism simplifies the overall control architecture while achieving the goal of sinusoidal current control and torque ripple reduction
Solution Approach 2:
The patent replaces direct mechanical measurement systems with computational estimation using the Kalman filter algorithm. Instead of using complex physical sensors and measurement systems, the controller uses mathematical models and available electrical measurements to estimate the required parameters, reducing hardware complexity while maintaining control performance
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
The solution effectively reduces noise and vibrations, allowing wind turbines to operate more quietly and be placed closer to settlements without disturbing the environment.
Implementation Method 1
a synchronous generator that generates an alternating current powered by the wind
Implementation Method 2
This alternating current is rectified and fed into an electrical supply network via an inverter
Data Source
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AI summary
The invention relates to a method for controlling a synchronous generator of a gearless wind energy turbine. Said synchronous generator comprises an electrodynamic rotor and a stator, for generating electrical power by rotating the rotor with respect to the stator. Said method comprising the following steps: generating a multi-phase output current on the stator, feeding the output current to a rectifier, controlling the output current by means of the rectifier such that torque ripple of the generator is reduced.