Wind Turbine Active Rectifier Control for Generator Vibration Reduction
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Solution Overview
Problem
Wind turbines experience vibrations and noise due to uneven air gaps between the stator and rotor, leading to oscillations in induced magnet wheel voltage and increased noise emissions.
Innovation Solution
A method involving the specification of rotor-fixed d and q coordinates for the generator's stator current, with an alternating component determined based on detected amplitude and phase position of electrical power oscillations, which is then added to the constant component to control the active rectifier using field-oriented control, effectively reducing mechanical frequency oscillations and associated vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an uneven air gap in the generator is present due to component tolerances, then manufacturing precision is improved (easier to manufacture), but vibrations and noise emissions increase
Solution Approach 1:
The invention changes the control parameters of the active rectifier by superimposing an alternating component on the d- and q-coordinates. This parameter change compensates for the uneven air gap effects by adjusting the current control signals to counteract the mechanical irregularities, thereby reducing vibrations and noise without requiring stricter manufacturing tolerances
Solution Approach 2:
The invention uses feedback from detected power oscillations at the generator to dynamically adjust the alternating component in the d- and q-coordinates. The control unit continuously monitors the power oscillations and modifies the rectifier control signals accordingly, creating a closed-loop system that actively compensates for air gap irregularities
2Device complexity
If conventional control methods are used without compensation for air gap irregularities, then device complexity is reduced (simpler control system), but vibrations and tower vibrations increase
Solution Approach 1:
The invention introduces an intermediary control mechanism that processes the relationship between generator power oscillations and rectifier control signals. The control unit acts as an intermediary by detecting power oscillations and translating them into compensating alternating components for the d- and q-coordinates, which then reduce tower vibrations without requiring direct mechanical modifications
3Object-generated harmful factors
If the active rectifier is controlled with alternating components in d- and q-coordinates, then electrical power oscillations are reduced, but control system complexity increases
Solution Approach 1:
The invention applies preliminary action by pre-calculating and superimposing the alternating component onto the d- and q-coordinates before they are applied to the active rectifier. This proactive compensation approach prevents power oscillations from developing in the first place, rather than reacting to them after they occur, thereby reducing control complexity
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 method significantly reduces electrical power oscillations and resulting vibrations and noise, allowing for precise control that minimizes tower vibrations and acoustic effects caused by irregular air gaps.
Implementation Method 1
The active rectifier is controlled at least as a function of this changed d and/or q coordinate, in particular using abc coordinates. This is preferably achieved by repeatedly transforming the changed d and/or q coordinates into abc coordinates. The rectifier is preferably controlled by a field-oriented control system.
Implementation Method 2
Due to an uneven air gap in the generator, caused for example by component tolerances, the amplitude of the induced rotor voltage at the stator windings can oscillate at the mechanical frequency of the rotor.
Data Source
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AI summary
The invention relates to a method for controlling, by means of field-oriented control, an active rectifier electrically connected to a stator of a wind turbine, wherein the generator comprises a stator having an axis of rotation about which the rotor is mounted, said method comprising the steps: predefining rotor-fixed d and q coordinates for at least one 3-phase stator current of the generator; determining at least one alternating component for the rotor-fixed d and/or q coordinate in accordance with a detected amplitude and a detected phase position of an electrical power oscillation at the generator, the determination of the alternating component for the rotor-fixed d and/or q coordinate taking into account a rotor position which represents a mechanical position of the rotor in relation to the stator; adding the alternating component for the rotor-fixed d and/or q coordinate to the rotor-fixed d and/or q coordinate to form a modified d and/or q coordinate; and controlling the active rectifier at least in accordance with the modified d and/or q coordinate.