Generator Converter Harmonic Torque Control for Ripple Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for harmonic control in wind turbine generators, such as those using permanent magnet synchronous machines, are inadequate in reducing undesired harmonics and torque ripple, relying on complex models that are difficult to measure and estimate, leading to unsatisfactory harmonic reduction.
Innovation Solution
A method for generating a converter control signal that derives harmonic torque and flux references based on feedback signals and demands, which are then used to calculate torque and flux errors, ultimately determining the switching state of the generator side converter portion to reduce harmonics and improve control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional methods apply simplifications and neglect parameters for implementation, then device complexity is reduced, but manufacturing precision (harmonic reduction) deteriorates
Solution Approach 1:
The invention changes the control parameters from conventional current-based control to torque and flux references derived from voltage and torque feedback signals. This parameter transformation enables direct harmonic control without requiring complex machine models, resolving the contradiction between control simplicity and harmonic reduction precision
Solution Approach 2:
The invention implements feedback mechanisms using torque feedback signals from accelerometers or strain gauges and voltage feedback signals from stator voltage measurements. These feedback loops continuously adjust harmonic torque and flux references to maintain precise harmonic control while keeping the control structure relatively simple
2Measurement precision
If high-fidelity models with many parameters are used for torque estimation, then measurement precision (torque estimation accuracy) is improved, but device complexity increases
Solution Approach 1:
The invention introduces torque feedback signals from external sensors (accelerometers, strain gauges, microphones) as intermediaries to obtain accurate torque information without requiring complex internal machine models. These external sensors directly measure torque or vibration related to torque ripple, providing accurate measurement without increasing control system complexity
Solution Approach 2:
The invention replaces complex electromagnetic modeling and torque estimation algorithms with direct mechanical measurement using accelerometers or strain gauges mounted on the generator bearing. This substitution provides accurate torque information while significantly simplifying the control system
3Ease of operation
If conventional FOC based on Id and Iq currents is used, then ease of operation is maintained, but manufacturing precision (harmonic reduction) deteriorates
Solution Approach 1:
The invention segments the control into distinct harmonic torque control and harmonic flux control components, each handled by separate controllers. This segmentation allows independent optimization of each control function while maintaining overall system simplicity, achieving both ease of operation and precise harmonic reduction
Solution Approach 2:
The invention transitions from conventional two-dimensional current control (Id-Iq plane) to a multi-dimensional control approach that includes torque references, flux references, and their respective feedback signals. This dimensional expansion enables precise harmonic control while maintaining operational simplicity through modular controller architecture
Data Source
AI summary
Provided is a method of generating a converter control signal for a generator side converter portion, in particular of a wind turbine, being coupled to a generator, in particular a permanent magnet synchronous machine, the method including: deriving at least one harmonic torque reference, in particular based on a harmonic torque demand and/or a torque indicating feedback signal; deriving at least one harmonic flux reference, in particular based on a harmonic stator voltage demand and/or a stator voltage indicating feedback signal; adding all of the at least one harmonic torque reference to a fundamental torque reference and subtracting an estimated generator torque to derive a torque error; adding all of the at least one harmonic flux reference to a fundamental flux reference and subtracting an estimated generator flux to derive a flux error; and deriving the converter control signal based on the torque error and the flux error.